Sunday, July 9, 2023

New data on African abelisaurs

Hi everyone.  I'm a coauthor on a paper published this week reviewing the record of African abelisauroids (de Souza-Júnior et al., 2023).  I want to thank André Luis de Souza-Júnior for adding me, as he used The Theropod Database as a resource.  That's how you do it!  We incorporated my corrections and suggestions back in 2020 before it was submitted, but as is typical of these projects there have been new discoveries since.  Here are some additional records-

unnamed Abelisauroidea (Lasseron, 2020)
Early Bathonian, Middle Jurassic
GEA 6, Guelb el Ahmar, Anoual Formation, Morocco
- (MNHN GEA6-5) lateral tooth (2.58x1.86x1.39 mm)
Early Bathonian, Middle Jurassic
GEA 7, Guelb el Ahmar, Anoual Formation, Morocco
(MNHN GEA7-14) lateral tooth (3.75x2.51x1.59 mm)
(MNHN GEA7-17) lateral tooth (2.60x2.06x1.09 mm)
Comments- Discovered in 2015 and/or 2018, Lasseron (2020) concluded "The convexity of the two carinae is a remarkable feature. It recalls the Abelisauridae (Smith, 2007; Hendrickx & Mateus, 2014), but also the Noasauridae (Carrano et al., 2002), an identification which would be consistent with the small size of these teeth. We therefore attribute these teeth to an Abelisauroidea gen. and sp. indet." (translated).
Reference- Lasseron, 2020. Paleobiodiversite, evolution et paleobiogeographie des vertebres mesozoiques africans et gondwaniens : apport des gisements du Maroc oriental. Doctoral thesis, Museum National D'Histoire Naturelle. 493 pp.

unnamed abelisauroid (Lasseron, 2020)
Berriasian, Early Cretaceous
Ksar Metlili, Ksar Metlili Formation, Morocco
- (FSAC-KM-A1-12) lateral tooth (3.41x2.26x1.47 mm)
Comments- Collected in 2010, 2015 or 2018, Lasseron (2020) concluded "The convexity of the two carinae is a remarkable feature. It recalls the Abelisauridae (Smith, 2007; Hendrickx & Mateus, 2014), but also the Noasauridae (Carrano et al., 2002), an identification which would be consistent with the small size of these teeth. We therefore attribute these teeth to an Abelisauroidea gen. and sp. indet." (translated).
Lasseron, 2020. Paleobiodiversite, evolution et paleobiogeographie des vertebres mesozoiques africans et gondwaniens : apport des gisements du Maroc oriental. Doctoral thesis, Museum National D'Histoire Naturelle. 493 pp.

undescribed possible abelisauroid (Smith, Lamanna, Dodson, Attia and Lacovara, 2001)
Cenomanian, Late Cretaceous
Bahariya Oasis, Baharija Formation, Egypt

Material- teeth (FABL 7.5 mm)
Comments- These "recently recovered" teeth are stated to have significantly more serrations per mm than similarly sized Deinonychus or Dromaeosaurus and have "denticle morphologies and the average crown base width (CBW) and CBL9crown base length] relationships ... more reminiscant of abelisaurids than dromaeosaurids."
Reference- Smith, Lamanna, Dodson, Attia and Lacovara, 2001. Evidence of a new theropod from the Late Cretaceous of Egypt. Journal of Vertebrate Paleontology. 21(3), 102A.

Kem Kem noasaurid cervical FSAC-KK-5016 in (A) right lateral, (B) left lateral, (C) anterior, (D) dorsal, (E) ventral and (F) posterior views (after Smyth et al., 2020). Scale = 10 mm.

unnamed Noasauridae (Russell, 1996)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco

Material- (CMN 41873; bone taxon H) distal humerus (48 mm wide) (Russell, 1996)
(FSAC-KK-5016) (~1.5 m) incomplete ~fourth cervical vertebra (21 mm) (Smyth, Ibrahim, Kao and Martill, 2020)
Comments- The humerus is very similar to Masiakasaurus.
References- Russell, 1996. Isolated dinosaur bones from the Middle Cretaceous of the Tafilalt, Morocco. Bulletin du Museum national d'Histoire naturelle. 18, 349-402.
Smyth, Ibrahim, Kao and Martill, 2020 (online 2019). Abelisauroid cervical vertebrae from the Cretaceous Kem Kem beds of southern Morocco and a review of Kem Kem abelisauroids. Cretaceous Research. 108, 104330.

Kem Kem abelisaurid axis FSAC-KK-5015 in (A) right lateral, (B) left lateral, (C) anterior, (D) dorsal, (E) ventral and (F) posterior views (after Smyth et al., 2020). Pink area is filler. Scale = 20 mm.

unnamed Abelisauridae (Fanti, Cau, Martinelli and Contessi, 2014)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco
- (CMN 50446) tooth (~24x~11x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 912) tooth (~17x~10x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 913) tooth (~22x~12x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 914) partial tooth (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
?(FSAC-KK 915) tooth (~18x~8x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
(FSAC-KK-5015) (~2.7 m) axis (38 mm) (Smyth, Ibrahim, Kao and Martill, 2020)
?(FSAC-KK unnumbered) tooth (~16x~11x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
(MNHN MRS 348) tooth (48x17x13 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 783) tooth (28x14x6 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 1266) tooth (34x14x7 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MNHN MRS 1838) tooth (36x19x9 mm) (Fanti, Cau, Martinelli and Contessi, 2014)
(MSNM V6053) tooth (~23x~10x? mm) (Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020)
Comments- Fanti et al. (2014) list measurements of four "Abelisauridae indet." teeth housed in the MNHN which have MRS numbers corresponding to the Gara Sbaa locality (e.g. Rebbachisaurus type) of the Kem Kem beds.  Smyth et al. suggested the axis FSAC-KK-5015 represents an abelisaurid outside Majungasaurinae+Brachyrostra, perhaps a juvenile Rugops.  Ibrahim et al. (2020) figure CMN 50446 and MSNM V6053 as "?Abelisaurid tooth", and several others as "Indeterminate theropod teeth" which seem to be abelisaurid based on the low distal curvature in each, and marginal undulations in FSAC-KK 912 and 915.
References- Fanti, Cau, Martinelli and Contessi, 2014. Integrating palaeoecology and morphology in theropod diversity estimation: A case from the Aptian-Albian of Tunisia. Palaeogeography, Palaeoclimatology, Palaeoecology. 410, 39-57.
Ibrahim, Sereno, Varricchio, Martill, Dutheil, Unwin, Baidder, Larsson, Zouhri and Kaoukaya, 2020. Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys. 928, 1-216.
Smyth, Ibrahim, Kao and Martill, 2020 (online 2019). Abelisauroid cervical vertebrae from the Cretaceous Kem Kem beds of southern Morocco and a review of Kem Kem abelisauroids. Cretaceous Research. 108, 104330.

Quseir abelisaurid left fibula in (F) lateral, (G, H) medial and (I, J) proximal views (after Salem et al., 2021). Scale = 20 mm.

unnamed probable abelisaurid (Sallam, O'Connor, Kora, Sertich, Seiffert, Faris, Ouda, El-Dawoudi, Saber and El-Sayed, 2016)
Middle Campanian, Late Cretaceous
Baris, El Hindaw Member, Quseir Formation, Kharga Oasis, Egypt
Material- (MUVP 187) proximal fibula (25x5 mm prox)
Comments- Discovered in 2008 or 2010, Sallam et al. (2016) initially reported "A proximal left fibula of a theropod dinosaur was also collected from the Baris area" and listed it as Theropoda indet..  Salem et al. (2021) noted the prominent m. iliofibularis tubercle is like abelisaurids and it has a "wide, slightly deep [proximomedial] fossa that closely resembles the condition in the abelisaurid Majungasaurus."  They say it "exhibits some affinities with abelisaurids" and refer to it as "Cf. Abelisaurid" in theit table 3. 
References- Sallam, O'Connor, Kora, Sertich, Seiffert, Faris, Ouda, El-Dawoudi, Saber and El-Sayed, 2016. Vertebrate paleontological exploration of the Upper Cretaceous succession in the Dakhla and Kharga Oases, Western Desert, Egypt. Journal of African Earth Sciences. 117, 223-234.
Salem, O'Connor, Gorscak, El-Sayed, Sertich, Seiffert and Sallam, 2021. Dinosaur remains from the Upper Cretaceous (Campanian) of the Western Desert, Egypt. Cretaceous Research. 123, 104783.

Elrhaz abelisaurid carina MNHN F.GDF-M30 in (E) labiolingual and (F) mesiodistal views (after Pochat-Cottilloux et al., 2022). Scale = 1 mm.

unnamed Abelisauridae (Pochat-Cottilloux, Allain and Lasseron, 2022)
Aptian, Early Cretaceous
GAD 5, Gadoufaoua, Elrhaz Formation, Niger
Material- (MNHN F.GDF-M30) two tooth fragments
(MNHN F.GDF-M37) two partial teeth
Comments- Collected in 1970, Pochat-Cottilloux et al. (2022) noted "some of this material was stored at the MNHN in a separate box" and had a "lighter color and a better quality of fossil preservation than other seen in other samples" which "suggested a different depositional environment to that of other samples so, as a result, this sample was separated from the rest" ... "as "site GADb"."  This is true for MNHN F.GDF-M30.  The authors state there are 3 serrations per mm on MNHN F.GDF-M30 and 4 per mm on MNHN F.GDF-M37, in the latter the carinae "extend along the entire length of both sides of the base" and in all specimens "the shape of the denticles and their number are typical of theropod teeth and could be assignable to Abelisauridae."
Reference- Pochat-Cottilloux, Allain and Lasseron, 2022. Microvertebrate fauna from Gadoufaoua (Niger, Aptian, Early Cretaceous). Comptes Rendus Palevol. 21(41), 901-926.

Galula abelisaurid tooth TNM 02088 in labial view (after O'Connor et al., 2006). Scale = 5 mm.

unnamed Abelisauridae (O'Connor, Gottfried, Stevens, Roberts, Ngasala, Kapilima and Chami, 2006)
Albian, Early Cretaceous
TZ-07, Namba Member of the Galula Formation, Tanzania

Material- (TNM 02088) lateral tooth (~19x~11.5x? mm)
(TNM coll.) eight lateral teeth, two anterior teeth
Comments- Discovered between 2002 and 2005, this material was described as theropod by O'Connor et al. (2006) and referred to the Unit I of the Red Sandstone Group at the time.  Roberts et al. (2010) subsequently revised the stratigraphic nomenclature, naming Unit I the Galula Formation.  Salem et al. (2021) refers the isolated teeth to Abelisauridae without comment, which seems likely given their stratigraphy, locality, size and morphology (particularly the nearly straight distal edge).  Several of the teeth were associated with the holotype of the titanosaur Shingopana, "suggesting a possible scavenging event."  Note the theropod caudals from the same locality described by O'Connor et al. differ from abelisaurids in their strong infradiapophyseal laminae and are here tentatively referred to Megaraptora.
Teeth have ~13-16 serrations per 5 mm mesially and distally.  O'Connor et al. further indicate "Two teeth are D-shaped in cross-section, indicating a position in the rostralmost portion of either the dentary or premaxilla."
References- O'Connor, Gottfried, Stevens, Roberts, Ngasala, Kapilima and Chami, 2006. A new vertebrate fauna from the Cretaceous Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania. Journal of African Earth Sciences. 44, 277-288.
Roberts, O'Connor, Stevens, Gottfried, Jinnah, Ngasala, Choh and Armstrong, 2010 (online 2009). Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa. Journal of African Earth Sciences. 57, 179-212.
Salem, O'Connor, Gorscak, El-Sayed, Sertich, Seiffert and Sallam, 2021. Dinosaur remains from the Upper Cretaceous (Campanian) of the Western Desert, Egypt. Cretaceous Research. 123, 104783.

Gokwe abelisaurid (left, right) and averostran (center) teeth (University of Zimbabwe coll.) (after Bond and Bromley, 1970).

undescribed Abelisauridae (Bond and Bromley, 1970)
Early Cretaceous
Gokwe Formation, Zimbabwe
- (University of Zimbabwe coll.) at least two teeth (~48x~31x?, ~49x~34x? mm)
Comments- Bond and Bromley (1970) were the first to figure three theropod teeth, discovered between 1962 and 1970, as their Plate 1A "Reptilian teeth of two types from the Gokwe Formation." Listed as being " in collection of Geology Department, University College of Rhodesia", the latter has since been renamed the University of Zimbabwe.  The first and third are clearly abelisaurid, with broad bases, straight to convex distal edges and fine serrations both mesially and distally (~6 per 5 mm on both carinae).  The second is narrower and more recurved, so referred to Averostra indet. here.
Reference- Bond and Bromley, 1970. Sediments with the remains of dinosaurs near Gokwe, Rhodesia. Palaeogeography, Palaeoclimatology, Palaeoecology. 8(4), 313-327.

Baharija abelisaurid tenth cervical vertebra MUVP 477 in (a) anterior, (b) posterior, (c) left lateral, (d) right lateral), (e) ventral and (f) dorsal views (after Salem et al., 2021).

unnamed possible brachyrostran (Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2021)
Early Cenomanian, Late Cretaceous
Gebel el Dist, Baharija Formation, Egypt
- (MUVP 477) (~5.8 m) tenth cervical vertebra (67.00 mm)
Comments- Discovered in 2016, Salem et al. (2021) added this to Tortosa et al.'s ceratosaur matrix and recovered it as an abelisaurid based on "(1) long axis of diapophysis forms angle of 65° to midsagittal plane; (2) dorsal surface of neural arch clearly delimited from lateral surface of diapophysis; (3) deep spinoprezygapophyseal and spinopostzygapophyseal fossae; and (4) well-developed epipophyses, comparable to those observed in the tenth cervicals of Majungasaurus and MPM 99 (but smaller than those of Carnotaurus and Ekrixinatosaurus novasi)."  The resulting Salem et al. (2022) publication officially describing the specimen did not use character 1.  While it was a brachyrostran (in a polytomy with Ekrixinatosaurus, Ilokelesia and the derived clade) in majority rule trees, a posteriori pruning of taxa was not done to determine if this is real signal or merely an artifact.  Examination of the 2022 supplementary data should resolve this.
References- Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2021. First definitive record of Abelisauridae from the Bahariya Formation, Bahariya Oasis, Western Desert of Egypt increases diversity of large-bodied theropods in the MIddle Cretaceous of northeastern Africa. The Society of Vertebrate Paleontology Virtual Meeting Conference Program, 81st Annual Meeting. 225-226.
Salem, Lamanna, O'Connor, El-Qot, Shaker, Thabet, El-Sayed and Sallam, 2022. First definitive record of Abelisauridae (Theropoda: Ceratosauria) from the Cretaceous Bahariya Formation, Bahariya Oasis, Western Desert of Egypt. Royal Society Open Science. 9: 220106.

Additionally, a review paper isn't really the place for new information or unpublished sources, so here are some extensive updates to poorly documented finds-

"Sidormimus" Molina-Perez and Larramendi, 2019
= "Dogosaurus" Anonymous, 2000 online
Aptian-Albian, Early Cretaceous
Gadoufaoua, Elrhaz Formation, Niger

Material- (MNN GAD coll.) (~1 m) partial skeleton including maxilla, cervical ribs, dorsal vertebrae, dorsal ribs, uncinate processes, sacral vertebrae, scapula, coracoid, sternal plates, sternal ribs, humerus, radius, ulna, carpus, manus including manual digit II, phalanges, manual unguals and manual claw sheath, pelvis including pubis and hindlimb including femur, tibia, fibula, calcaneum, metatarsus, pedal digit II, pedal digit III, pedal digit IV and pedal unguals
Comments- This specimen was discovered on September 13 2000 and announced by Lyon (2000 online) as "a brand new, dog-sized theropod, which the team has affectionately (but unofficially) named "Sidormimus."" and a "new, dog-sized carnivore - perhaps one of the smallest dinosaurs ever", with a photo of the specimen in situ.  The same photo was labeled Dogosaurus on a dispatch from Project Exploration on the National Geographic website, which also stated it was "no more than three feet long. Its slender neck and ribcage were preserved poking out of the rock. Its long, clawed hind leg was uncovered as we dug around the exposed bones." Sereno et al. (2004) first announced the specimen in print, as "a small (1 m) articulated skeleton showing many abelisauroid and noasaurid synapomorphies, including pneumatized presacral and sacral neural arches, proportionately long presacral centra, and others" and "preserves a maxilla and pelvic girdle, the former of which bears the distinctive abelisaurid pit-and-groove texturing of the skull bones."  They include it in their cladogram as "Gadoufaoua noasaurid", but it is not an OTU in the matrix.  It is also listed in Sereno and Brusatte (2008) as "undescribed noasaurid" in a faunal list, and is noted to have a pubic boot more with limited expansion than the "Kryptops" postcrania MNN GAD1-2. Sidor (pers. comm. 2005) confirms the "Sidormimus" specimen is the Elrhaz noasaurid. Sereno (2010) devoted an SVP abstract to it, noting the specimen has- long and robust posterior cervical ribs, dorsal centra more than twice as long as tall, five uncinate processes (unique among non-maniraptoran theropods), posteriorly directed glenoid, enlarged coracoid, ossified sternal plates and ribs, forelimb 18% of hindlimb length, robust deltopectoral crest and olecranon process, manual digit II longer than III, straight manual unguals, tibia longer than femur, pedal digits II and IV much shorter than III, and short flat pedal unguals.  Sereno (2017) provided further information- straight tibia, weak iliofibularis tubercle on fibula, fibula distally fused with calcaneum, no dorsal vascular groove on pedal unguals.  The co-occuring Afromimus shared fibular-calcaneum fusion but differs in the other characters, in addition to having a more robust proximal fibula and distal fibula which is expanded transversely.  Molina-Perez and Larramendi (2019) first used the name in print, specified to be a nomen nudum.
References- Lyon, online 2000.
Anonymous, online 2000.
Sereno, Wilson and Conrad, 2004. New dinosaurs link southern landmasses in the Mid-Cretaceous. Proceedings of the Royal Society, Series B. 271, 1325-1330.
Sereno and Brusatte, 2008. Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger. Acta Palaeontologica Polonica. 53(1), 15-46.
Keillor, Sereno and Masek, 2010. Range of movement in a noasaurid forelimb: In situ data and joint reconstruction. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 114A.
Sereno, 2010. Noasaurid (Theropoda: Abelisauroidea) skeleton from Africa shows derived skeletal proportions and function. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 162A.
Sereno, 2017. Early Cretaceous ornithomimosaurs (Dinosauria: Coelurosauria) from Africa. Ameghiniana. 54, 576-616.
Molina-Perez and Larramendi, 2019. Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes. Princeton University Press. 288 pp.

"Titanovenator" Boyd, 2020 online
"T. kenyaensis" Boyd, 2020 online
Maastrichtian, Late Cretaceous
Lapurr sandstone (= Turkana Grits), Turkana, Kenya
- (KNM-WT coll.) (~11-12 m) multiple specimens including cranial material (including a partial skull - premaxilla, postorbital and braincase), axial material and appendicular material (including astragalocalcaneum)
Comments- Discovered in 2004, this is based on unassociated material referred to one taxon "based on morphological consistency and on the recovery of specimens from a narrow stratigraphic and geographic area."  Abelisaurid characters listed by Sertich et al. (2013) include- "a tall, rugose premaxilla, an anteroventrally inclined posterior border of the postorbital," ... "a prominent dorsal projection of the parietals and supraoccipital" and an "ascending process [that] is low and subrectangular, separated from the anterior surface of the astragalus by a distinct fossa."  They further note the "skull is strongly coossified, with a thickened but weakly sculptured skull roof", "no prominent cranial ornamentation is evident" and "the astragalocalcaneum is completely coossified and displays a prominent transverse sulcus on the anteroventral surface."  The museum collection is based on an azhdarchid vertebra found by the same team from the same locality (O'Connor et al., 2011).
Boyd (2020) included the name Titanovenator kenyaensis in the pdf visual portion of her "Ask a Geologist" presentation for RUGM.  It accompanies a photo of the MCN Carnotaurus cast that is also labeled Abelisauridae gen. et sp. nov., and based on the name refers to Sertich et al.'s (2013) giant Kenyan abelisaurid taxon.  It is a nomen nudum as the pdf was not "issued for the purpose of providing a public and permanent scientific record" (ICZN Article 8.1.1) and doesn't "state the date of publication in the work itself" (Article 8.5.2), while the name itself was not "registered in the Official Register of Zoological Nomenclature (ZooBank)" (Article 8.5.3) or "accompanied by a description or definition that states in words characters that are purported to differentiate the taxon" (Article 13.1.1).  The name (as "Titanovenator kenyanis") actually predates Boyd's presentation, originating on a Jurassic Park message board from 2013 in a post under the pseudonym Rex Fan 684, but this is not considered a source for catalogued nomina nuda here.
References- Sertich, Manthi, Sampson, Loewen and Getty, 2006. Rift Valley dinosaurs: A new Late Cretaceous vertebrate fauna from Kenya. Journal of Vertebrate Paleontology. 26(3), 124A.
O'Connor, Sertich and Manthi, 2011. A pterodactyloid pterosaur from the Upper Cretaceous Lapurr sandstone, west Turkana, Kenya. Anais da Academia Brasileira de Ciências. 83(1), 309-315.
McCoy, 2013 online.
Sertich, Seiffert and Manthi, 2013. A giant abelisaurid theropod from the Latest Cretaceous of northern Turkana, Kenya. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 211.
Boyd, 2020 online. Ask a Geologist: Geology & Paleontology of Kenya. Rutgers Geology Museum. 25 pp.

Duwi abelisaurid teeth (MGUP coll.; lost) in (left) labiolingual and (right) basal view (after Gemmellaro, 1921).

unnamed Abelisauridae (Di Stefano, 1919)
Late Campanian, Late Cretaceous
Duwi Formation, Al Sharauna, Egypt

Material- (MGUP MEGA002; lost?) tooth (16.63x13.01x6.69 mm) (described by Smith and Lamanna, 2006)
Late Campanian, Late Cretaceous
Duwi Formation, Al Sharauna, Gebel Duwi and/or Gebel Nakheil, Egypt

(MGUP MEGA001) partial lateral tooth (?x~22.7x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP MEGA002 B) lateral tooth (~35.2x~25x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP MEGA003) partial lateral tooth (?x~30x? mm) (Di Patti, pers. comm. 6-2023)
(MGUP coll.; lost) more than two lateral teeth
Comments- Gemmellaro (1921) referred several remains to Megalosaurus crenatissimus, from three localities in eastern Egypt.  The phosphate layers of Gebel Duwi are the Late Campanian Duwi Formation (e.g. Salama et al., 2021).  Similarly, "Phosphate mines at Kosseir-el-Khadim, Gebel Nakheil, near Kosseir [now Quseer], on the Red Sea" are also the Duwi Formation (Valentine, 1985).  The third locality has been mistaken in every subsequent reference as "Sciarauna-el-Ghibli, presse Sibaiya (Valle del Nilo)", but the 'c' is actually a poorly photocopied 'e', as indicated by Di Stefano's (1919) original publication of the expedition which states "The richest and most extensive deposit is the one found on the hill of Seiarauna, on which are the two villages called Seiarauna-el-Bahri, i.e. Seiarauna at the river, and Seiarauna-el-Ghibli, i.e. upstream" (translated). The latter is now known as Ash Sharawinah al Qibliyah, El-Sharâwna el-Qiblîya or simply Al Sharauna among other variants, and is indeed directly across the Nile from Sebaiya (also called As Sibaiyyah and Al Sebaaia West City).  Smith and Lamanna (2005) stated the particular tooth they described was from "near Idfu in the Nile Valley of Egypt (Fig. 1, exact locality data are unknown; research in Palermo did not reveal a more accurate location)", but Idfu (also called Edfu) is 30 km to the southeast.  Gemmellaro states "the majority of the specimens came from [Seiarauna-el-Ghibli]. But a careful research recently conducted by myself on the abundant material donated by Cortese has allowed me to find all the types studied also in the locations of Gebel Nakheil (Kosseir-el-Khadim and Uadi-el-Anz mines) and of Gebel Duwi" (translated), suggesting no other localities were involved and perhaps 30 km was considered "near" by whoevever wrote that record.
Di Stefano (1919) first reported theropod material from Al Sharauna, collected by him in 1912 and also donated to the MGUP by Cortese between then and his publication- "In contact between the phosphates and the alternating marls, bones and quite a few dinosaurian teeth (Mosasaurus, Platecarpus, Megalosaurus, etc.) are found, which will be the subject of a special study."  That study was Gemmellaro (1921), who as noted above also discovered theropod material in the Gebel Duwi and Gebel Nakheil collections.  Unfortunately, Gemmellaro never specifies which of the three localities any of his discussed specimens is from, nor does he state how many teeth were in the MGUP collections.  Three teeth are figured, with those in figures 12 and 13 typically abelisaurid with low crowns serrated to the base both mesially and distally.  Curvature and crown height ratios are most similar to posterior dentary teeth of Majungasaurus.  Gemmellaro compares the teeth favorably to Majungasaurus syntypes FSL 92.306a and b and a Maevarano tooth figured by Thevenin 1906 (MNHN coll.).  A smaller, third tooth is illustrated as figure 14, said to be among "some which, although sharing some common features, differ in the shape of the crown which is not backward curved but is almost isosceles with the sides having a profile slightly convex or straight."  While Gemmellaro believed "such differences in shape and in dimensions between teeth has to be attributed to the diverse locations they occupied in the jaws, and also to the different age of the individuals whom the teeth belonged to", the mesiodistally narrower crown suggests another taxon such as a noasaurid, and that tooth is listed as Averostra indet. here.  Gemmellaro described two unguals and figured one.  While he compares them favorably to crenatissimus syntype FSL 92.290, the preserved section of the figured specimen is less tapered in side view with no obvious vascular groove, and this holds true as well for other Majungasaurus pedal unguals (e.g. FMNH PR 2434, MSNM V6418, V6419) as well as Masiakasaurus (e.g. FMNH PR 2135) and indeed most theropods.  Photos provided by Di Patti (pers. comm. 6-2023) show the figured element (MGUP MEGA004) is a sauropod pedal ungual while the other (MGUP MEGA005) compares well to an ankylopollexian manual ungual I.  They are referred to Titanosauria indet. and Hadrosauroidea indet. here based on age.
Smith and Lamanna (2006) described one of Gemmellaro's teeth in detail (MGUP MEGA002), although it is not one previously figured.  They identified it as abelisaurid based on "the distal curvature profile exhibits almost no curvature and is tilted slightly toward the apex in lateral view" (but this is not true of Gemmellaro's Figure 12), and as closer to Majungasaurus and Lameta AMNH 1753/1955 than Rugops, Rugops? sp. UCPC 10 or Bajo Barreal UNPSJB-PV 247 based on "mesial curvature profile begins at a strong curve at about 1/3 the crown height basal to the apex (but this is not true of Gemmellaro's Figure 12) and "the ... interdenticular sulci complex forms an intermediate condition between being absent and well developed" (unknown in Gemmellaro's figured specimens).  They find "The discriminant analysis (DA) correctly identified 96.6% of the teeth in the sample and classified MGUP MEGA002 as Majungasaurus" but note "the assignment of the Egyptian tooth to the genus Majungasaurus in particular is unlikely given that Africa and Madagascar were separated by the Mozambique Channel throughout the Cretaceous", and indeed the relatively low sample of abelisaurid teeth tested makes this questionable.  In fact he combination of stout shape plus concave basal distal edge with a convex apical distal edge is unlike figured Majungasaurus teeth.
Interestingly, the MGUP only has three teeth in their collection now (Di Patti, pers. comm. 6-2023), none of which are MGUP MEGA002 or match the three illustrated by Gemmellaro.  One (MGUP MEGA002 B) is abelisaurid based on the slightly convex distoapical edge, although the mesial edge is similar to Gemmellaro's Figure 12 instead of curving abruptly at a third of its height.  Marginal undulations are present as in some other abelisaurids (Abelisaurus, Chenanisaurus, Majungasaurus, Skorpiovenator).  There are ~10 mesial serrations per 5 mm and ~11 distal serrations.  The other two teeth (MGUP MEGA001 and MGUP MEGA003) are more partially preserved but of similar size and serration density (~10 distal serrations per 5 mm in MEGA001; ~10.5 mesial serrations per 5 mm in  MEGA003), and each shows marginal undulations as well, so they are tentatively placed as Abelisauridae here.  There are no precise locality data for any of them past Maastrichtian of Egypt.
References- Di Stefano, 1919. Osservazioni sul Cretaceo e sull'Eocene del Deserto Arabico di el-Sibaiya, nella valle del Nilo. Bollettino del R. Comitato Geologico d'Italia. Serie V(47), 1-39.
Gemmellaro, 1921. Rettili maëstrichtiani di Egitto. Giornale di Scienze Naturali ed Economiche. 32, 339-351.
Valentine, 1985. Structure and tectonics of the southern Gebel Duwi area, Eastern Desert of Egypt. Department of Geology and Geography, University of Massachusetts. Contribution No. 53, 141 pp.
Smith and Lamanna, 2006. An abelisaurid from the Late Cretaceous of Egypt: Implications for theropod biogeography. Naturwissenschaften. 93(5), 242-245.
Salama, Altoom, a Allam, Ajarem and Abd-Elhameed, 2021. Late Cretaceous anacoracid sharks (Squalicorax) from Duwi Formation, Gebel Duwi, central Eastern Desert, Egypt: Qualitative and quantitative analyses. Historical Biology. 33(11), 3056-3064.

Reference- de Souza-Júnior, Candeiro, da Silva Vidal, Brusatte and Mortimer, 2023. Abelisauroidea (Theropoda, Dinosauria) from Africa: A review of the fossil record. Papéis Avulsos de Zoologia. 63, e202363019.

Sunday, May 21, 2023

Raven et al. 2023 on ankylosaur phylogeny missed the shortest trees and should not have dropped Nodosauridae

A new paper came out analyzing thyreophoran phylogenetics - Raven et al. (2023).  The abstract states "This dataset was analysed using equal- and implied-weights parsimony and Bayesian inference, and further explored using constraint trees and partitioned datasets. Stratigraphical congruence was used to identify a 'preferred tree' and these analyses reveal a novel hypothesis for thyreophoran relationships. The traditional ankylosaurian dichotomy is not supported: instead, four distinct ankylosaur clades are identified, with the long-standing 'traditional' clade Nodosauridae rendered paraphyletic. Ankylosauridae, Panoplosauridae, Polacanthidae and Struthiosauridae have distinct morphotypes..."

Four distinct ankylosaur clades with distinct morphotypes?

It sounds intriguing, but then Polacanthidae as a separate clade or grade has been a viable hypothesis since 1998, so I guess it's the paraphyly of Panoplosaurus and Struthiosaurus versus Ankylosaurus that is new?  Looking back, that was ambiguous in Vickaryous et al. (2001),  Osi (2005) and Parsons and Parsons (2009) but rejected by Osi and Makadi (2009), Thompson et al. (2012) and Arbour et al. (2016), thus it would be surprising to someone like myself who doesn't specialize in ornithischians so is not all that familiar with character support and such.

So let's see what Raven et al. found.  They did five basic analyses (A-D with [edited thanks to David Marjanovic's comment] progressively more different assumed weighting- unweighted, then k = 3, 8 and 12; E as a Bayesian attempt) then some constraint analyses and ones using only certain parts of the skeleton.  I'm going to ignore the latter as I don't think anyone considers "cranial only", "postcranial only" or "armor only" to give better results in Mesozoic dinosaur phylogenetics.  In any case, the first analysis (Analysis A) was equal weights, which is the standard for Mesozoic dinosaur analyses and how basically every prior ankylosaur analysis was run.  As an aside, statements like "The strict consensus tree (Supplementary material, Fig. S75) shows a lack of resolution in Stegosauria" .... "and Ankylosauria is found in an unresolved polytomy with most stegosaur taxa" just means you haven't pruned enough taxa a posteriori to see the underlying structure.  It's annoying the authors never look into what that structure is and leave the tree looking artificially uncertain.  But the main result in Ankylosauria is... "There are two clades within Ankylosauria (Ankylosauridae + Nodosauridae)"!  So the expected usual result.  Hmm.  But what about their novel hypothesis of three nodosaur clades at least? 

They state "Within Nodosauridae, there are three groupings of taxa: 'polacanthid' ankylosaurs, but excluding Polacanthus; a 'panoplosaurid' group typified by Edmontonia and Panoplosaurus; and a 'struthiosaurid' group typified by Struthiosaurus and Hungarosaurus."  But are there?  Just look at the cladogram above (which is only in the supp info). 'Polacanthidae excluding Polacanthus' is Texasetes, the then-unnamed Patagopelta, Sauropelta, Hylaeosaurus, Hoplitosaurus, Tatankacephalus, an undescribed Wessex specimen, Zhejiangosaurus, Antarctopelta and Dongyangopelta.  Besides Hoplitosaurus and Hylaeosaurus (which I don't know has ever been recovered as a polacanthid, just guessed to be there), I don't think any of these have been associated with Polacanthidae/inae before.  The 'core' polacanthids besides Polacanthus itself are Gastonia, Mymoorapelta and maybe Gargoyleosaurus, so I wouldn't say this clade is reflective of Polacanthidae in any sense.  But okay you say, maybe it's not Polacanthidae, but surely the analyses (PLURAL as in the abstract) revealed a 'distinct morphotype' for this Sauropelta-Hylaeosaurus clade of nodosaurs?  Looking at their "preferred tree" (Analysis B, k=3) only Patagopelta, Texasetes, Hoplitosaurus and Hylaeosaurus are shared between 'polacanthid' clades, with five new taxa in there compared to Analysis A.  And in Analysis C (k=8) only Hoplitosaurus and Texasetes are shared (with seven new taxa), while by Analysis D (k=12) all these taxa are scattered to the wind and there's no equivalent at all.  And Analysis E (Bayesian) is one huge polytomy for ankylosaurs.  So I would suggest their published results do not support any clade like this that is robust when analyzed under different criteria.

But what about Panoplosauridae and Struthiosauridae?  First of all, just as there are nine 'nodosaurs' that fall outside the Nodosauridae+ Ankylosauridae split, there are one to five nodosaurids that don't fall into either the panoplosaur or struthiosaur clades.  We can't tell how many because Raven et al. do not prune a posteriori to try to resolve any polytomies.  But the panoplosaur group is Dracopelta, Aletopelta, both Edmontonia species, Denversaurus and of course Panoplosaurus.  The latter three have always been grouped together, but the first two would be interesting if they actually were panoplosaurs.  The 'preferred tree' (k=3) takes away Aletopelta and adds Nodosaurus, Anoplosaurus and Tianchisaurus; Analysis C (k=8) has the core three genera plus Dracopelta and Anoplosaurus, while Analysis D (k=12) has everything in A plus Anoplosaurus and Nodosaurus.  So Dracopelta is always a panoplosaur and Anoplosaurus is with any unequal weighting, which are the first surprising, new and widely supported nodosaur placements in this study.  Yet neither is touted in the text or written up with character support, and honestly the idea of Albian-Cenomanian English Anoplosaurus and especially Jurassic European Dracopelta breaking up not just Campanian-Maastrichtian North American Panoplosaurus+Edmontonia, but the genus Edmontonia itself(!) just seems unlikely.  And indeed, a fairly complete Dracopelta specimen (Russo and Mateus, 2023) was recently discovered, and the authors found "D. zbyszewskii [was] consistently recovered as sister taxa of G[argoyleosaurus] parkpinorum, from the Upper Jurassic of Morrison Formation, USA, in a basal ankylosaur group that also includes the other Morrison Formation ankylosaur, M[ymoorapelta] maysi," which matches temporally so much better.

As for Struthiosauridae, the unweighted tree would have this include Borealopelta, Minmi, Niobrarasaurus, Polacanthus, Europelta, Liaoningosaurus, Stegopelta, the Paw Paw Formation juvenile (* see below), Hungarosaurus and all three Struthiosaurus species (not monophyletic, at least Tianchisaurus is closer to S. transylvanicus than to S. austriacus or S. languedocensis).  The 'preferred tree' (k=3) keeps only Struthiosaurus, Hungarosaurus, the Paw Paw juvenile and Europelta, and adds Silvisaurus and Taohelong.  Analysis C (k=8) drops the latter two but adds Tianchisaurus back, and Analysis D (k=12) keeps the two and everything from the unweighted tree plus adds Invictarx and Hoplitosaurus.  So far from dividing the 'distinct morphotypes' of Polacanthidae and Struthiosauridae, two of five trees have Polacanthus as a struthiosaur.  Here the results are besides the Santonian-Maastrichtian Central European Struthiosaurus/Hungarosaurus, the struthiosaur clade includes Europelta (as guessed by its describers), the Early Cretaceous American Paw Paw juvenile and usually the Jurassic Chinese Tianchisaurus.  Yet the authors never mention the Paw Paw juvenile ever falling out here, and have Tianchisaurus as a panoplosaurid because Analysis B is the one time it wasn't the sister to Struthiosaurus transylvanicus.  In fact, the authors falsely* state the Paw Paw juvenile is usually a basal ankylosaur and Figure 2 incorrectly* shows it being one in a supposed "Agreement subtree of the three implied weighing analyses (analyses B–D)."  How did this happen?! ...

(*) I figured it out- the trees in the supp info switched Pawpawsaurus and the Paw Paw juvenile, while figures 1-3 in the paper are correct.  So actually their trees have Pawpawsaurus as the struthiosaur sister to Hungarosaurus, which has the same chronostratigraphic issues as the juvenile from the same formation.

If we go back to the big picture in Ankylosauria, the unweighted Analysis A gave us a large Nodosauridae with some mostly Jurassic taxa basal to the Nodo-Ankylo split, and a few 'nodosaurs' (Kunbarrasaurus, Peloroplites, Liaoningosaurus) as basal ankylosaurids.  'Preferred' Analysis B (k=3) has polacanthids basal to the split, then panoplosaurs and struthiosaurs sister to each other, so again is pretty standard.  Analysis C (k=8) has struthiosaurs, panoplosaurs and polacanthids successively closer to ankylosaurids, so at least that has the paraphyletic nodosaurs the article touts.  Finally, Analysis D (k=12) has struthiosaurs further from ankylosaurids than panoplosaurs while polacanthids cease to really exist (their internal specifier Gastonia [see below] is an ankylosaurid but Polacanthus and Hoplitosaurus are struthiosaurs).

So I guess if I had a takeaway from their published results (**, see below), it would be that Dracopelta (probably incorrectly) and usually Anoplosaurus are panoplosaurs; Europelta, Pawpawsaurus and usually Tianchisaurus (not even supported by the authors) are struthiosaurs; polacanthids are not strongly supported in any form; and nodosaurs become increasingly paraphyletic with more weighting greater values of k (corrected again thanks to David Marjanovic's comment), although you need to get to k=8 for anything really novel.  And it's the weighting that is one of my major issues with this paper, because why is k=3 the preferred tree?  Because "The stratigraphically most congruent topology, as identified by the four stratigraphical congruence metrics (SCI, RCI, MSM and GER), was Analysis B, and so this was selected as the 'preferred tree'."  But if you look at their Table 2 (below), the Bayesian analysis destroys the others at SCI (0.929 vs. 0.438-0.500), but we never get to know what those results are since the authors just leave it as a huge polytomy without further analysis.  And in the other three, Analysis B is 16.954, .023 and .005 better respectively, which seems increasingly less important.  I have no idea how any of these measures work, but it seems incredibly arbitrary to say whichever k value is best in a majority of four methods wins, ignoring anything quantitative.

(**) Raven et al. didn't find the shortest trees

But now we get to the part where I reveal nothing I said above matters, because Raven et al. didn't get the shortest trees.  EDIT BELOW Not even close.  Instead of producing "eight MPTs with lengths of 1508 steps", their unweighted matrix Analysis A results in >99999 MPTs of 1464 steps.  Here's the real strict consensus with 13 taxa pruned a posteriori for resolution-

As you can see, it's not the same as Raven et al.'s Figure S75.  For one, stegosaurs resolve, although weirdly with Toujiangosaurus+Paranthodon as ankylosaurs.  For two it's WAY less resolved in Ankylosauria.  All those taxa from Zhejiangosaurus through Ahshishlepelta never form a consistent clade with each other or the four ankylosaur clades, and if you prune all nine genera, struthiosaurs, ankylosaurids and 'panoplosaurs'+polacanthids are still a trichotomy.  So their matrix doesn't actually show how these taxa relate (besides polacanthids being sister to 'panoplosaurs').  Isn't it ironic though that we do get Raven et al.'s three nodosaur clades including a classic Polacanthinae that includes Gastonia, Gargoyleosaurus and Mymoorapelta in addition to Jurassic Sarcolestes (and basally some parankylosaurs, but the paper was too late to include Stegouros)?  Struthiosauridae is only Struthiosaurus spp. plus Hungarosaurus and Tianchisaurus, which again is funny because the latter was not included in the clade by the authors due only to their Analysis B.  'Panoplosauridae' includes a lot more taxa, and yes those basal ones don't clade with each other or successively to the core group no matter how many are pruned, so that's another real polytomy.  As for the pruned taxa-

Mongolostegus can at least be sister to Chungkingosaurus or a struthiosaurine.
Adratiklit is part of the Dacentrurus+Stegosaurus clade.
Anodontosaurus and Scolosaurus are part of the Euoplocephalus+Pinacosaurus clade.
Tarchia kielanae is part of the Ankylosaurus+Euoplocephalus clade.
Acantholipan can be a 'panoplosaur', a struthiosaurine or outside (by which I mean a taxon closer to Ankylosaurus than Toujiangosaurus but not part of the struthiosaur, ankylosaurid or polacanthid+'panoplosaur' clades shown, though it could be e.g. sister to any of these clades and thus fall under their definitions).
Borealopelta can be a struthiosaurine, a 'panoplosaur' or outside(?).
Europelta can be a struthiosaurine or outside.
Invictarx can be a struthiosaurine, a 'panoplosaur' or outside.
Nodosaurus is always closer to Panoplosaurus than Silvisaurus.
Patagopelta can be a basal 'panoplosaur' or outside.
Pawpawsaurus can be a struthiosaurine or 'panoplosaur'.
Stegopelta can be a struthiosaurine or outside.

EDIT ADDED 5-21: Thanks to Andrea Cau in the comments for pointing out Raven et al. didn't include their character ordering settings in their txt file.  I wrongly assumed it would have a ccode line or a ctype line below the matrix but never scrolled all the way down.  I should have been suspicious when I had to manually choose the outgroup instead of them just making Lesothosaurus the first taxon in the matrix.  On the one hand, my bad.  On the other hand, it's surely best practice to not force your readers to modify the settings of the file you provided to the journal.

In any case, it still doesn't matter because Raven et al. STILL didn't find the shortest trees.  Instead of producing "eight MPTs with lengths of 1508 steps", their unweighted matrix Analysis A results in >99999 MPTs of 1506 steps.  Here's the real REAL strict consensus with 13 taxa pruned a posteriori for resolution-

Two steps doesn't sound like much, but it's enough to make 'polacanthids' a grade of basal ankylosaurids, make struthiosaurines nodosaurids as in traditional phylogenies and kick Dracopelta and Anoplosaurus out of panoplosaurs.  And yes, Nodosaurus is still closer to Panoplosaurus than Silvisaurus or Struthiosaurus.  The toplogy still has Tuojiangosaurus+Paranthodon as ankylosaurs and a struthiosaur Tianchisaurus too.

What are these clades named?

Raven et al. propose new definitions for their three nodosaur families-

All ankylosaurs more closely related to Panoplosaurus than to Ankylosaurus, Struthiosaurus austriacus or Gastonia burgei

All ankylosaurs more closely related to Gastonia burgei than to Ankylosaurus, Panoplosaurus or Struthiosaurus austriacus

All ankylosaurs more closely related to Struthiosaurus austriacus than to Ankylosaurus, Panoplosaurus or Gastonia burgei"

Tim Williams has already rightfully complained on the DML that their Polacanthidae definition needs to use Polacanthus foxii.  Why is this so hard in 2023?!  Do Arbour and the "three anonymous referees" not know the basics of phylogenetic nomenclature?  PhyloCode Article 11.10 states "when a clade name is converted from a preexisting name that is typified under a rank-based code or is a new or converted name derived from the stem of a typified name, the definition of the clade name must use the type species of that preexisting typified name or of the genus name from which it is derived (or the type specimen of that species) as an internal specifier."  We've been complaining about it since Sereno 24 years ago, surely every dinosaur worker knows by now.

Another obvious issue is that Nodosauridae has priority over Panoplosauridae, Struthiosauridae and Polacanthidae, so where's Nodosauridae?  Raven et al. explain "Nodosaurus is recovered outside of
Panoplosauridae in Analyses A and C, further suggesting that application of the name Nodosauridae would add confusion."  But as noted above, Nodosaurus is actually always a 'panoplosaur' when Analysis A is run correctly, and the fact it's supposedly an ankylosaurid sister to Dyoplosaurus when k=8 (fig. S77) should be close to worthless in my view.  Unless one of the authors wants to claim whatever character is being weighed eight times more than others could realistically mean this Cenomanian taxon is really within a Campanian species complex that are so similar they were all placed under Euoplocephalus tutus until recently?  Also, Polacanthus doesn't fall in their definition of Polacanthidae in two of their four trees, so why is that still allowed as a family name?

In any case, the clades have already been officially defined with PhyloCode registrations, by Madzia et al. (2021).  Raven et al. was "Received 7 February 2022", so I don't know why Arbour (a coauthor on Madzia et al.!) or the reviewers would let that stay in the paper.  Reading through, Raven et al. actually cite Madzia et al. and state "the underlying philosophy of the latter study is based on the PhyloCode (de Queiroz & Cantino, 2020) and offers an alternative hypothesis to our study, which is framed by the traditional principles of the International Commission on Zoological Nomenclature (1999), and so is not discussed further." Hahahaha  I hate to tell you guys, but defining clades based on phylogenetic relationships has nothing to do with the ICZN.  And if you were following the "traditional principles" of the 1999 ICZN, you couldn't just throw Nodosauridae away while stating "In the 'preferred' tree Panoplosauridae consists of ... Nodosaurus" and "A clade of generally Late Cretaceous North American taxa is also recovered here and named Panoplosauridae. As well as Denversaurus, Edmontonia spp., Nodosaurus and Panoplosaurus..."  Instead you would follow ICZN Article 65.2.3 - "by the discovery that the type genus was, when established, based on a type species then misidentified, the author may fix as the type species a nominal species as prescribed in Article 70.3. If the threat cannot be overcome by the fixation of a type species under the provisions of Article 70.3 the case is to be referred to the Commission for a ruling."  But that's not happening because I bet they think it's unlikely Nodosaurus is outside Nodosauridae.  "... is not discussed further" is short here for "... we know it makes no sense but we don't want to address it."

And Madzia et al. do a good job because they actually follow the rules.  Except in Raven et al.'s topology Stegosauridae ends up being the Chungkingosaurus+Eurypoda clade due to Huayangosaurus' weird position outside Eurypoda (which supposedly happens in the Bayesian analysis too), which could be saved by adding Ankylosaurus magniventris as an external specifier.  Similarly, Struthiosaurini might benefit from an Ankylosaurus magniventris external specifier due to the polytomy.  So here's the actual unweighted results with official clade names-

1. Ankylosauria; 2. Ankylosauridae; 3. Ankylosaurinae; 4. Ankylosaurini; 5. Eurypoda; 6. Huayangosauridae; 7. Nodosauridae; 8. Nodosaurinae; 9. Polacanthinae; 10. Shamosaurinae; 11. Stegosauria; 12. Struthiosaurini. Note due to Nodosaurus' possible positions, Panoplosaurini cannot be placed precisely in this tree.

For a couple final thoughts, Raven et al.'s definition for Shamosaurinae ("All ankylosaurid ankylosaurs more closely related to Shamosaurus than to Ankylosaurus") is better than the official definition ("max ∇ (Gobisaurus domoculus Vickaryous et al., 2001 & Shamosaurus scutatus Tumanova, 1983 ~ Ankylosaurus magniventris Brown, 1908") because Gobisaurus has no reason to be involved.  Also, Kirkland et al.'s (2013) definition of Struthiosaurinae is just horrible- "the most inclusive clade containing Europelta but not Cedarpelta, Peloroplites, Sauropelta or Edmontonia."  Doesn't separate it from ankylosaurids or polacanthines, includes Cedarpelta and Peloroplites which have no agreed upon positions or competing family-level names, AND doesn't use Struthiosaurus austriacus as the internal specifier.  Oof.  And why have "Bayesian analysis' as a keyword in Raven et al. (2023), run the Bayesian analysis for a week, mention it in the abstract, and despite having by far the best SCI score just leave it as a huge ankylosaur polytomy that has no effect on its conclusions?

So does nobody test run these analyses before they are accepted?

I began this post just planning to harp on peoples' seeming inability to learn Phylocode Article 11.10, but it ended up so much worse.  It's not like I searched and scoured to find a better cladogram in the data, TNT popped it out in (checking) under 30 seconds.  And then there's the Pawpawsaurus vs. Paw Paw juvenile switch that made the supp info wrong that I guess nobody noticed?  I'm just a person looking over the article on a random Saturday, not a journal editor or a professional whose job description woefully includes peer reviewing.  And sure mistakes are made, maybe the authors are anti-Phylocode despite proposing phylogenetic definitions (what organization is going to lend yours any validity?) and maybe nobody on the team knows how to use TNT, but I also just found the basic results quote from the top of my post to be misleading.  The published results did NOT show that nodosaurs fall into three "distinct morphotypes" past the standard Latest Cretaceous Central European struthiosaurines and North American panoplosaurins except for maybe 2-5 additional genera, NOR that they were more paraphyletic than normally thought and basically nothing was shown about polacanthines, with the statement "'polacanthid' ankylosaurs, but excluding Polacanthus" in Analysis A being plain wrong.  My best guess is that after getting pretty inconclusive results the team went with the "Nodosauridae isn't real" gimmick despite the hypocrisy in keeping Polacanthidae.  I think the real message of the analysis (assuming accurate scorings) is that ankylosaurs need a lot more characters analyzed to determine their basal relationships. the basic topology from twenty years ago is still most parsimonious.

References- Vickaryous, Russell, Currie and Zhao, 2001. A new ankylosaurid (Dinosauria:
Ankylosauria) from the Lower Cretaceous of China, with comments on ankylosaurian relationships. Canadian Journal of Earth Sciences. 38(2), 1767-1780.

Osi, 2005. Hungarosaurus tormai, a new ankylosaur (Dinosauria) from the Upper Cretaceous of Hungary. Journal of Vertebrate Paleontology. 25(2), 370-383.

Osi and Makadi, 2009. New remains of Hungarosaurus tormai (Ankylosauria, Dinosauria) from the Upper Cretaceous of Hungary: Skeletal reconstruction and body mass estimation. Palaontologische Zeitschrift. 83, 227-245.

Parsons and Parsons, 2009. A new ankylosaur (Dinosauria: Ankylosauria) from the Lower Cretaceous
Cloverly Formation of central Montana. Canadian Journal of Earth Sciences. 46(10), 721-738.

Thompson, Parish, Maidment and Barrett, 2012. Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora). Journal of Systematic Palaeontology. 10, 301-312.

Kirkland, Alcala, Loewen, Espılez, Mampel and Wiersma, 2013. The basal nodosaurid ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of northeastern Spain. PLoS ONE. 8, e0080405.

Arbour, Zanno and Gates, 2016. Ankylosaurian dinosaur palaeoenvironmental associations were influenced by extirpation, sea-level fluctuation, and geodispersal. Palaeogeography, Palaeoclimatology, Palaeoecology. 449, 289-299.

Madzia, Arbour, Boyd, Farke, Cruzado-Caballero and Evans, 2021. The phylogenetic nomenclature of ornithischian dinosaurs. PeerJ. 9, e12362.

Raven, Barrett, Joyce and Maidment, 2023. The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora). Journal of Systematic Palaeontology. 21(1), 2205433.

Russo and Mateus, 2023. Review of Dracopelta zbyszewskii, an ankylosaur from the Upper Jurassic of Portugal. 14th Symposium on Mesozoic Terrestrial Ecosystems and Biota. The Anatomical Record. 306(supp. 1), 221-223.

Friday, January 20, 2023

Are uncinate processes ancestral to Archosauria? A look at Wang et al 2023

A paper was published on January 17th (Wang et al., 2023) that I've been looking forward to since its SVP 2020 poster (Wang et al., 2020).  The basic idea is that uncinate processes leave attachment scars on ribs even if the processes themselves are unossified, and these scars show that uncinate processes were much more widespread than the record of ossified processes would suggest.  In theropods, ossified uncinate processes are only known in many pennaraptorans, Pelecanimimus and the noasaurid "Sidormimus" (Sereno, 2010; not mentioned by Wang et al., 2023) for instance, but Wang et al. found scars in Struthiomimus, Gorgosaurus and Allosaurus, all of which definitely lacked ossified processes.  Similarly, Wang et al. identified scars in Apatosaurus, when I don't think any sauropodomorph has been reported with ossified processes.

So my first question in 2020 was "do any archosaurs NOT show these scars?", and the SVP abstract and poster didn't say.  Even in the published paper, the most we get in the main section is "Using an alternate coding approach in which uncinate processes were coded as absent in taxa represented by five or more dorsal vertebral ribs that all lacked uncinate scars, nine archosaur taxa were coded as lacking uncinate processes."  Which nine taxa?  Who knows.  The Methods section at the end of the paper similarly says "Our alternative coding approach, which was used to test the stability of the results obtained under our preferred coding approach, differed in that uncinate processes were coded as absent in taxa for which at least five vertebral ribs were available, regardless of their state of preservation, and showed no sign of uncinate processes or uncinate scars. This resulted in coding uncinate processes as absent in nine taxa."  It does detail that their outgroup, the proterochampsian Chaneresuchus, lacks the scars so was assumed to lack any uncinate processes, but that's it.

Their only figure besides two showing the scars is Figure 3, an "informal consensus cladogram", whose caption reads "Major clades of Archosauria with evidence of cartilaginous uncinate processes are labelled and shaded blue; clades with evidence of ossified uncinate processes are labelled and shaded pinkish red; clade with evidence of both cartilaginous and ossified uncinate processes is labelled and shaded purple; and clades for which no evidence is available are labelled and shaded grey."  Clades shaded gray are Shartegosuchidae, Pachycephalosauria, Macronaria and Megalosauroidea, the latter being the most basal theropod clade shown.  I guess the nine mystery taxa belong to those clades?  Also note every branch in each blue clade is blue, every branch in every red clade is red, etc., implying homogeniety.  Here's the figure-


It turns out the identity of the Mystery Nine is in Table 2 of the Supplementary Information, under Alternate Coding.  In the preceding paragraph they again report "Under the alternate coding method, nine taxa were scored as lacking uncinate processes."  These taxa are- Lotosaurus, Protosuchus, Lagerpeton, Plateosaurus, Anchisaurus, Camarasaurus, Camptosaurus, Parasaurolophus, Edmontosaurus, Protoceratops and Chasmosaurus.  Wait, that's actually eleven taxa, not nine, despite the number nine being stated three times.  On the one hand, note none of these are shartegosuchids, pachycephalosaurs, or megalosauroids, so why are those clades even in the cladogram?!  On the other hand, note that Lotosaurus and Protosuchus would make two gray nodes basal to mesoeucrocodylians, Lagerpeton would be a gray node basal to dinosaurs, and Plateosaurus and Anchisaurus would be two extra gray nodes basal to sauropods.  Also all of the Ornithopoda and Ceratopsida [sic] branches are blue when they shouldn't be.  So the figure is putting in artificial discrepancy and leaving out most of the actual discrepancy.

The big methodological problem with the paper is that their Preferred Coding approach scored "the presence of uncinate processes as uncertain (?) if evidence of uncinate processes or scars was lacking."  So the Mystery "Nine" were actually all scored as unknown, even though Chaneresuchus was scored as absent (0) based on identical evidence.  So obviously if you score all the archosaurs as present or unknown and the sole non-archosaur as absent, you're going to get archosaurs ancestrally having uncinate processes.  And when they use the Alternate Coding of taxa without scars not having uncinate processes, they themselves report-

"Maximum likelihood and Bayesian inference recovered cartilaginous uncinate processes as the most likely condition at Archosauria (pml=0.61, pmb=0.55), but only when branch length estimates were incorporated. By contrast, maximum likelihood excluding branch length estimates recovered the absence of uncinate process as the most likely condition at Archosauria (pml=0.92). The ancestral condition at Dinosauria could not be recovered with confidence using either maximum likelihood or Bayesian inference (pml=0.57, pmb ≈ 0.33). Maximum likelihood recovered ossified uncinate processes as the most likely condition at Maniraptoriformes (pml=0.90) and Pennaraptora (pml=0.99), but only when branch length estimates were excluded from the analysis. Bayesian inference could not confidently recover the ancestral conditions at Maniraptoriformes (pmb=0.33) and Pennaraptora (pmb=0.33)."

So not strongly supporting "deep reptilian evolutionary roots of a major avian respiratory adaptation", and that's not even going into how the only non-avian paravians they scored were four dromaeosaurids (Microraptor, Saurornitholestes, Velociraptor and Deinonychus) with ossified processes, when at least Archaeopteryx, anchiornithines and omnivoropteryids lacked them, so anything about Pennaraptora's ancestral state is going to need more than "oviraptorosaurs, dromaeosaurids, Rhea, Gallus and Lithornis - yes, Chauna - no."

And yeah, the living bird Chauna has no uncinate processes and lacks any scars for them, so was rightfully scored 0.  Yet fossil taxa with the same morphology were scored unknown.  Which again points to the flaw in their Preferred Coding, but also suggests we might expect homoplasy in other parts of Archosauria as well.  So lambeosaurines and edmontosaurins could have lacked uncinates while kritosaurins had them, following the osteological evidence, for instance.

In conclusion, it's an excellent idea to look for osteological correlates to unossified uncinate processes, and we got some real data hidden in the supplementary information, but any use was marred by unforced errors like a misleading main figure and a nonsensical scoring methodology.  I wouldn't doubt uncinates were primitive to at least averostrans, given "Sidormimus" and Edmarka (check Figure 14A of Bakker et al., 1992; so Megalosauroidea should have ironically been blue), but the concept deserved better vetting than this.

References- Bakker, Kralis, Siegwarth and Filla, 1992. Edmarka rex, a new, gigantic theropod dinosaur from the Middle Morrison Formation, Late Jurassic of the Como Bluff outcrop, with comments on the evolution of the chest region and shoulder in theropods and birds and a discussion of the five cycles of originn and extinction among giant dinosaurian predators. Hunteria. 2(9), 1-24.

Sereno, 2010. Noasaurid (Theropoda: Abelisauroidea) skeleton from Africa shows derived skeletal proportions and function. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 162A.

Wang, Sullivan and LeBlanc, 2020. Anatomical and histological data indicate uncinate processes to be homologous across Archosauria. Journal of Vertebrate Paleontology. Program and Abstracts 2020, 334.

Wang, Claessens and Sullivan. 2023. Deep reptilian evolutionary roots of a major avian respiratory adaptation. Communications Biology. 6:3.

Monday, January 9, 2023

"Scrotum humanum" a torvosaur and Jurassic Chinese theropod updates - The Theropod Database January 2023

Happy New Years everyone!  Sorry about how long it took to post the update, but I was covering too many sections at once.

Darren Naish's post on Middle Jurassic British theropod femur OUMNH J29757 and "Scrotum humanum" led me to do something that's been on my list for a while- compare the one original figure of "Scrotum" to other theropods to see if is really Megalosaurus as has long been assumed.  Turns out it's closer to another closely related taxon...

"Scrotum" Brookes, 1763
"S. humanum" Brookes, 1763
Aalenian-Bajocian?, Middle Jurassic
unknown quarry, Inferior Oolite?, Cornwell, England

Material- (lost) distal femur (~235 mm trans)
Diagnosis- (proposed) ectocondylar tuber limited to medial half of ectocondyle; ectocondyle subequal in size and shape to endocondyle.
Comments- Originally described and illustrated by Plot (1677) as the distal femur of a giant human, this is famous as being the first Mesozoic dinosaur bone to be published. Brookes (1793) later summarized Plot's description and opinions but labeled the specimen Sctrotum Humanum in his plate. Rieppel (2022) notes that "At the top of page 317, Brookes (1763) noted that 'other stones have been found exactly representing the private parts of a man; and others in the shape of kidneys . . . ', and continued further down on the same page" described the femur.  As "the plates and the individual figures they contain are not numbered separately, but are identified by the pagination number of the page on which the respective specimens are mentioned or described. The conclusion seems to be that the illustrator took the femur fragment to be an example of those stones referred to on page 317 as 'exactly representing the private parts of a man', and erroneously labelled it accordingly."  Phillips (1871) believed it was from the Inferior Oolite (Aalenian-Bajocian) and stated "It may have been the femur of a large megalosaurus or a small ceteosaurus" without evidence.  As described by Delair and Sargeant (1975), Halstead (1970) "pointed out that because of its date of publication (post-Linnean, i.e. after 1758), this binomen can be considered a perfectly valid publication of the first generic and specific name ever applied to dinosaurian remains. It is perhaps fortunate that the name was not thereafter employed by any subsequent worker, and thus Scrotum humanum Brookes must be treated as a nomen oblitum and discarded."  They (and Halstead) considered it more probable to be Megalosaurus than Cetiosaurus without evidence and stated "The specimen unfortunately is lost."  Halstead and Sarjeant (1993; publication duplicated in 1995) noted that while Scrotum should be treated as a nomen oblitum under ICZN Article 23b (First Edition), "no application was made then, or has been made since, for the formal suppression of Brookes's binomen."  The Third Edition of the ICZN came out in 1985 and eliminated the nomen oblitum clause, so the authors petitioned the ICZN in 1992 "(I) to use its plenary powers to suppress the generic name Scrotum Brookes, 1763 and the specific name S. humanum Brookes, 1763; (2) to retain on the Official List of Generic Names in Zoology the name Megalosaurus Buckland in Parkinson, 1822, type species by subsequent designation M. bucklandi Meyer. 1832. (3) to retain on the Official List of Specific Names in Biology the name bucklandi as published in the binomen Megalosaurus bucklandi (specific name of the type species of Megalosaurus Buckland in Parkinson, 1822, by designation in Meyer, 1832); (4) To place on the Official List of Rejected and Invalid Generic Names in Zoology the name Scrotum Brookes, 1763; (5) to place on the Official List of Rejected and Invalid Specific Names in Zoology the name humanum Brookes, 1763, as published in the binomen Scrotum humanum, and as suppressed in (1) above." as listed in 1993.  As recalled by the authors, Tubbs (Executive Secretary to the ICZN) replied later that year that "The text on p. 301 of Brookes (1763) makes it quite clear that the two words "Scrotum humanum" on the plate were a description of a specimen, and that Brookes did not establish a genus Scrotum or a species humanum (any more than he did a species Kidney stone on the same plate!). The words just happened to be Latin."  Furthermore, since "[the name Scrotum humanum] has never been used as a scientific name", it "is therefore unavailable under Article 11d of the Code" (Third Edition- "Names to be treated as valid when proposed. - Except as in (i) below, a name must be treated as valid for a taxon when proposed unless it was first published as a junior synonym and subsequently made available under the provisions of Section e of this article.").  Finally, because "Plot's long-lost specimen was ... not certainly, a Megalosaurus bone", Tubbs wrote that "the Commission is willing to take action only when there is an appreciable and real, as opposed to hypothetical, threat to stability or nomenclature. This is not the case for Megalosaurus."  Note that Tubbs was incorrect that Brookes ever specified Scrotum Humanum was a description instead of a name, with page 301 being an unrelated section on plant fossils, so his use of Article 11d was unwarranted although recently supported by Rieppel's logic.  He was also wrong that it had never been used as a scientific name, as Molnar et al. (1990) listed Scrotum humanum as a carnosaur nomen dubium.  Under the current ICZN, "Scrotum humanum" would be a nomen nudum based on Article 11.5- "To be available, a name must be used as valid for a taxon when proposed."  Tubbs was right that the referral to Megalosaurus was merely hypothetical though, as it has never been supported by published evidence and seems unwarranted.
The femur is dissimilar from Cetiosaurus (both the lectotype OUMNH J13615 and the Rutland specimen LCM G468.1968) in being 45-86% larger, having a distally extended medial condyle, and a fibular groove placed at the lateral edge.  Note the estimated transverse diameter is based on Plot's statement the narrowest shaft circumference was 15 inches (= 381 mm) and scaled from the figure.  Compared to this, Megalosaurus femora are slightly smaller (shaft diameter 265-343 mm), and differ in having a more distomedially extended and pointed medial condyle, more laterally positioned ectocondylar tuber, and a straight lateral edge until the distal extent of the tuber.  These same differences are also usually present in e.g. Cruxicheiros, piatnitzkysaurids, Eustreptospondylus, Erectopus, Allosaurus, and Juratyrant among large Jurassic theropods whose distal femora are undistorted and figured in posterior view.  If "Scrotum" is from the Inferior Oolite it is also earlier than Megalosaurus, and differs from the contemporaneous Magnosaurus in the same ways when preserved (more laterally positioned ectocondylar tuber; straight lateral edge until the distal extent of the tuber), although it could derive from Duriavenator with which it cannot be compared.  Sinraptor dongi is slightly more similar to "Scrotum" in having a convex lateral edge alongside the ectocondylar tuber, but it is "Brontoraptor" which is most similar in having that character, an evenly rounded medial condyle and a more medially placed ectocondylar tuber.  Torvosaurus (ML 632) shows the last character at least but cannot be evaluated for the rest, so "Scrotum" might be best characterized as a torvosaur and may relate to "Megalosaurus" "phillipsi" from the Kimmeridgian of England that also has characters similar to "Brontoraptor" and Torvosaurus.  "Brontoraptor" also has a similar circumference (376 mm) and internal cavity size based on Siegwarth et al.'s Figure 8E.  Whether the remaining differences (ectocondylar tuber limited to medial half of ectocondyle; ectocondyle subequal in size and shape to endocondyle) are genuine or illustration error caused by Plot generalizing then unfamiliar megalosauroid anatomy is uncertain.  Note "Scrotum" can be excluded from Ceratosauria based on the absence of a tall anteromedial crest, and from Coeluridae, Proceratosauridae and Maniraptoromorpha based on the deep extensor groove described by Plot and large size (with occasional exceptions, e.g. Yutyrannus).
References- Plot, 1677. The Natural History of Oxford-shire, being an essay towards the Natural History of England. Oxford. 358 pp.
Brookes, 1763. The Natural History of Waters, Earths, Stones, Fossils and Minerals, with their Virtues, Properties and Medicinal Uses: To which is added, the methods in which Linnaeus has treated these subjects. Vol. 5. J. Newberry. 364 pp.
Robinet, 1768. Vue philosophique de la gradation naturelle des formes de l'être, ou les essais de la nature qui apprend a faire l'homme. Harrevelt. 260 pp.
Phillips, 1871. Geology of Oxford and the Valley of the Thames. Oxford at the Clarendon Press. 523 pp.
Halstead, 1970. Scrotum humanum Brookes 1763 - the first named dinosaur. Journal of Insignificant Research. 5(7), 14-15.
Delair and Sargeant, 1975. The earliest discoveries of dinosaurs. Isis. 66, 5-25.
Buffetaut, 1979. A propos du reste de dinosaurien le plus anciennement décrit: l'interprétation de J.-B. Robinet (1768). Histoire et Nature. 14, 79-84.
Molnar, Kurzanov and Dong, 1990. Carnosauria. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria. University of California Press. 169-209.
Halstead and Sarjeant, 1993. Scrotum humanum Brookes - the earliest name for a dinosaur? Modern Geology. 18, 221-224.
Halstead and Sarjeant, 1995. Scrotum humanum Brookes - the earliest name for a dinosaur? In Sarjeant (ed.), 1995. Vertebrate Fossils and the Evolution of Scientific Concepts; A tribute to L. Beverly Halstead. Gordon and Breach. 219-222.
Delair and Sargeant, 2002. The earliest discoveries of dinosaurs: The records re-examined. Proceedings of the Geologists' Association. 113, 185-197.
Rieppel, 2022 (online 2021). The first ever described dinosaur bone fragment in Robinet's philosophy of nature (1768). Historical Biology. 34(5), 940-946.

"Scrotum humanum" distal femur (lost; leftmost; after Plot, 1677), compared to (left to right) "Brontoraptor" (TATE 0012; after Siegwarth et al., unpublished), Megalosaurus bucklandii (NHMUK 31806; after Benson, 2010b), Magnosaurus nethercombensis (OUMNH J12143; after Benson, 2010a).

Also updated is Chienkosaurus, which thanks to the recent description of Sinraptor dongi teeth by Hendrickx et al. (2020), I feel can be placed in Metriacanthosauridae.  This and Szechuanosaurus were coincidentally recently reviewed by Curtice at his blog I've started following, Dr. BC's Hindsight at Fossil Crates, which I highly recommend.

Chienkosaurus Young, 1942
C. ceratosauroides Young, 1942
Tithonian?, Late Jurassic
IVPP locality 47, upper Guangyuan Group, Sichuan, China

Lectotype- (IVPP V237A) (~8 m) posterior premaxillary tooth (44x16x12 mm)
Referred- ?(IVPP V193) ulna (164 mm) (Young, 1942)
Bathonian-Callovian?, Middle Jurassic
IVPP locality 49, middle Guangyuan Group, Sichuan, China

?(IVPP V190) (~5 m) ~ninth caudal centrum (66 mm) (Young, 1942)
Other diagnoses- Young (1942) originally diagnosed Chienkosaurus with- "Teeth thick and sharply pointed with fine palisade denticulations on both sides. The anterior which are finer than the posterior ones push lingually
towards the base and form a ridge topping at a distance before the base of the tooth."
Comments- The material was discovered in late Spring 1941, with the type consisting of four isolated teeth IVPP V237A-D.  Young's (1942) diagnosis was "Mainly based upon" the largest tooth (V237A), with the three smaller teeth considered immature and (possibly incorrectly) lacking their bases.  He stated "The general shape of the teeth resembles that of Labrosaurus stechowi" which was prescient as both are based on mesial dentition, and considered Chienkosaurus a ceratosaurid based on the questionably referred postcrania.  Ironically, "Labrosaurus" stechowi is now thought to be ceratosaurid, but as Young noted Chienkosaurus lacks its lingual fluting which has proven to be a ceratosaurid character.  Subsequently, Chienkosaurus was generally placed in Megalosauridae (e.g. Romer, 1956; Steel, 1970; Dong et al., 1978) when it was used as a waste basket for almost all large Jurassic theropods including Ceratosaurus and later Yangchuanosaurus.  Note Huene (1959) when citing Chienkosaurus as named in 1958 from the Late Cretaceous of Shantung meant to list Chingkankousaurus.  Dong et al. (1983) reported that "Rozhdestvensky (1964) proposed that the four teeth of Chienkosaurus could possibly belong to the Crocodilia" (translated), but which work this corresponds to was not listed in the bibliography and cannot be determined.  Dong et al. also stated "during the editing of "The Handbook of Chinese Fossil Vertebrates," Zhiming Dong conducted a review of these four specimens and formally confirmed that the best preserved tooth among the V237 collection was a premaxillary tooth of a carnosaurian dinosaur, but that the remaining three teeth were assignable to the crocodile Hsisosuchus."  The dentition of Hsisosuchus has not been described or figured in enough detail to distinguish it from theropods, but two of the teeth (IVPP V237B and V237D) are similar in being short and barely recurved with a high crown base ratio, characters shared with the tooth figured separately in Hsisosuchus' type description.  They are provisionally placed in Hsisosuchus sp. here.  The third supposed Hsisosuchus tooth (IVPP V237C) is different in having a distinctly D-shaped section with strong carinae somewhat like Guimarota tyrannosauroid premaxillary tooth IPFUB GUI D 89, so is provisionally placed in Tyrannosauroidea here.  Retaining only one of Chienkosaurus' syntype teeth in the genus would make it the lectotype, and as ICZN Article 74.5 states "In a lectotype designation made before 2000, either the term "lectotype", or an exact translation or equivalent expression (e.g. "the type"), must have been used or the author must have unambiguously selected a particular syntype to act as the unique name-bearing type of the taxon", and Dong et al. explicitly make Chienkosaurus a synonym of Szechuanosaurus, and of Chienkosaurus' syntypes only consider IVPP V237A to be theropodan, this is here considered a valid lectotype designation.  Rozhdestveksy (1977) earlier listed Szechuanosaurus campi and Chienkosaurus ceratosauroides as "synonyms?" in his Table 1 without comment, while Dong et al.'s synonymization was based on examining Yangchuanosaurus teeth from CV 00214 to correctly determine "the differences among carnosaur dentitions are due only to being in a different position in the dentition" and noting Chienkosaurus' and Szechuanosaurus' types are from the same locality.  While this indeed makes it possible they even derive from the same individual, none of the teeth have been shown to be diagnostic within metriacanthosaurids, and synonymization should be based on autapomorphies or unique combinations of characters instead of provenance.  This synonymization of part of the Chienkosaurus type with Szechuanosaurus was followed by Molnar et al. (1990) where they consider the taxon an allosaurid, which makes sense as Dong was a coauthor.  Most recently, Hendrickx et al. included Chienkosaurus in their cluster analyses, although the taxon is never mentioned in the text, matrices or table of examined taxa.  Classical/Hierarchical clustering resolves it with Genyodectes, Sinraptor dongi (the only metriacanthosaurid analyzed there) and Allosaurus, while neighbour joining clustering resolves it sister to a clade whose basal members are 'Indosuchus' AMNH jaws, Allosaurus and S. dongi
Young placed locality 47 at "the top part of the Kuangyuan Series and immediately below the Chentsianyen conglomerate", now known as the Guangyuan Group and the Chengqiangyan Group, with the former corresponding to the Xiashaximiao Formation through the Penglaizhen Formation.  As it was found "immediately below" the boundary (layer 8b in Young et al., 1943), Chienkosaurus may be from the Penglaizhen Formation or slightly lower Shuining Formation.  The age is listed as Tithonian on fossilworks and in Weishampel (1990), the latter cited as from "Dong (pers. comm.)". 
The tooth is similar to many large theropod teeth in general characters, but is from the premaxilla as evidenced by the twisted mesial carina and reduced extent of mesial serrations. The crown base ratio (.75) is between the third and fourth premaxillary teeth of Sinraptor dongi's holotype (pm3 .60; pm4 1.04), which also match in size (pm3 FABL 16.87 mm; pm4 BW 12.26 mm) and in lacking mesial serrations basally.  The cited mesial (15 per 5 mm) and distal (6.7-10 per 5 mm) serration densities are matched by teeth of S. dongi, and the strong mesial carina Young describes could easily be due to the "longitudinal groove adjacent to the mesial carina, on the lingual surface of the crown" "clearly present in lpm3 and lpm4" as described by Hendrickx et al. (2020) for S. dongi.  Thus Chienkosaurus is indistinguishable from Sinraptor dongi as far as can be determined from the description, and given its poorly constrained age could be contemporaneous or even synonymous.  Hendrickx et al.'s matrices show no differences between Yangchuanosaurus shangyouensis (including Y. magnus), Sinraptor dongi and S. hepingensis that can be evaluated for Chienkosaurus, so pending Hendrickx's in prep. study on metriacanthosaurid dental anatomy the genus is considered Metriacanthosauridae indet..
Referred material- Young (1942) figured and described an ulna from the type locality (IVPP V193), stating he "would prefer to refer this ulna to Chienkosaurus ceratosauroides above described."  The element is very different from Limusaurus in having marked transverse expansions proximally and distally as well as a triangular versus reniform proximal end, so that if Sinocoelurus is closely related to that genus the ulna is unlikely to belong to it.  Eoabelisaurus has a much longer olecranon.  The ulnae of megalosaurids and Kaijiangosaurus is far more robust with more proximally extended olecranons, while those of most coelurosaurs (e.g. Zuolong, Guanlong, Coelurus, Tanycolagreus, Fukuivenator) are much more slender with developed olecranons as well.  Fukuiraptor has a dissimilar ulna with a strong olecranon, prominent anteroproximal longitudinal ridge and unexpanded distal end.  This leaves several roughly comparable taxa whose ulnae have been figured in anteroposterior view- Ceratosaurus, Poekilopleuron, Yangchuanosaurus, Allosaurus and Haplocheirus.  Young compared it favorably to the former, writing "it fits rather well with the ulna of Ceratosaurus nasicornis (length of ulna, 17.7 cm.) which is only slightly longer than the present form", and indeed the main difference in profile is the more gradual proximal expansion laterally.  However, in proximal view IVPP V193 differs from Ceratosaurus and most other proximally figured ulnae in having a centrally placed olecranon (also seen in Coelurus, but not Tanycolagreus).  While only photographed in anterior view, the ulna of Yangchuanosaurus (CV 00214) would also seem to have a centrally placed olecranon, so IVPP V193 may be correctly referred to Chienkosaurus/Szechuanosaurus after all.
Young (1942) describes IVPP V190 as "A complete centrum of an anterior caudal vertebra (or posterior lumbar) with length 66 mm., breadth 41 mm., minimum breadth of the centrum 24 mm", noting it "fit in size with Chienkosaurus ceratosauroides" and calling it Theropoda indet. in the plate caption but also saying there it "probably belonging to Chienkosaurus ceratosauroides."  With a length/height ratio of 144% it is comparable to the ninth caudal of Sinraptor hepingensis and indistinguishable in lateral view.  It differs in being 85% wider than tall vs. 95%, but this is within the range of variation in hepingensis' caudals.  Notably, this is from a different locality than the type, said by Young to be in "the middle part of the" ... "Kuangyuan Series", layer 5a in Young et al. (1943), and thus possibly corresponding to the Shangshaximiao Formation.  Thus while lacking a plausible connection to Chienkosaurus, it is congruent with being metriacanthosaurid but may also be e.g. piatnitzkysaurid or megalosaurid.
References- Young, 1942. Fossil vertebrates from Kuangyuan, N. Szechuan, China. Bulletin of the Geological Society of China. 22(3-4), 293-309.
Young, Bien and Mi, 1943. Some geologic problems of the Tsinling. Bulletin of the Geological Society of China. 23(1-2), 15-34.
Romer, 1956. Osteology of the Reptiles. University of Chicago Press. 1-772.
Huene, 1959. Saurians in China and their relations. Vertebrata PalAsiatica. 3(3), 119-123.
Steel, 1970. Part 14. Saurischia. Encyclopedia of Paleoherpetology. Gustav Fischer Verlag. 1-87.
Rozhdestvensky, 1977. The study of dinosaurs in Asia. Journal of the Palaeontological Society of India. 20, 102-119.
Dong, Zhang, Li and Zhou, 1978. [A new carnosaur discovered in Yongchuan, Sichuan]. Chinese Science Bulletin. 23(5), 302-304.
Dong, Zhou and Zhang, 1983. Dinosaurs from the Jurassic of Sichuan. Palaeontologica Sinica. Whole Number 162, New Series C, 23, 136 pp.
Molnar, Kurzanov and Dong, 1990. Carnosauria. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria. University of California Press. 169-209.
Weishampel, 1990. Dinosaurian distribution. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria. University of California Press. 63-139.
Hendrickx, Stiegler, Currie, Han, Xu, Choiniere and Wu, 2020. Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China. Canadian Journal of Earth Sciences. 57(9), 1127-1147.

Lectotype tooth of Chienkosaurus ceratosauroides in mesial and basal views (after Young, 1942).

Also newly revealed to be metriacanthosaurid is "Yuanmouraptor"-

"Yuanmouraptor" Anonymous, 2014
Middle Jurassic
Yuanmou County, Yunnan, China
- (ZLJ 0115) partial skull, mandibles (one incomplete, one partial), postcrania
Comments- This specimen is on display at the ZLJ as a new carnosaur, but has yet to be described. There is a mounted skeleton, but how much is original is unreported.  Hendrickx et al. (2019) call this "an undescribed metriacanthosaurid (ZLJT 0115)", state it has mesial and lateral teeth with "four to six, possibly more" flutes, and list it as "Metriacanthosauridae indet." in their Appendix 1 indicating information was from photos provided by Stiegler.
References- Anonymous, 2014. Special Exhibition: Legends of the Giant Dinosaurs. Hong Kong Science Museum newsletter. 1-3-2014, 2-7.
Hendrickx, Mateus, Araújo and Choiniere, 2019. The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends. Palaeontologia Electronica. 22.3.74, 1-110.

As part of a review of Jurassic Chinese theropods, I went over the largest Jurassic theropod, previously referred to Szechuanosaurus campi.

unnamed averostran (Camp, 1935)
Middle Jurassic?
Jung-Hsein UCMP V1501, middle Chongqing Group, Sichuan, China

Material- (UCMP 32102) (~14.7 m) mesial dentary tooth (~69x~22x? mm), rib fragment, ischial fragment, femoral fragment (~1.33 m)
Comments- The specimen was collected on August 30 1915 by Louderback.  Note the UCMP locality number is V1501 (as determined in their online catalogue), not V151 as listed by Camp.  Jung-Hsien is now called Rongxian, a county in Zigong City.  Camp stated "The beds in which they occur have been called the Szechuan series", which was a term for the stratigraphic section from the Early Jurassic Qianfuyan (= Tsienfuyan) Formation and Ziliujing (= Tsuliuching, = Tzeliutsin) Formation to the Cretaceous Chengqiangyan (= Chengtsiangyen) Group and Jiading (= Chiating, = Tshiating) Group, depending on north versus south in the Sichuan Basin. Rongxian is located in the south, so UCMP V1501 would be part of the Ziliujing-Chongqing-Jiading sequence, and Young (1937; see also Young et al., 1943) placed it above the Ziliujing Formation but below the conglomerates of the Jiading Group, and thus within the Middle-Late Jurassic Chongqing Group.  Furthermore, Young (1937) stated "The fossiliferous horizon discovered by Louderback lies probably between our horizons 2 and 3, some 200 meters above horizon 2" which is the type locality of Omeisaurus junghsiensis.  As Omeisaurus is generally recovered in the Xiashaximiao Formation and horizon 3 is another 300 meters above where Young placed UCMP V1501 (so may be the Penglaizhen or Suining Formation), UCMP 32102 may derive from the Shangshaximiao Formation.  Dong et al. (1983) listed it as deriving from that formation, perhaps using the same logic although they did not describe any explanation.
Camp (1935) initially referred the specimen to Megalosauridae because histology "shows quite definitely that the relationship of the Chinese form is with Allosaurus" instead of Tyrannosaurus.  However, the plate shows this is because the sampled section of Tyrannosaurus femur (labeled AMNH 5886, but this is the Anatotitan paratype, and it is more probably Dynamosaurus holotype AMNH 5866 that is known to be histologically sampled) is composed of secondary osteons, while those of Allosaurus and UCMP 32102 are fibrolamellar bone.  Yet Allosaurus can develop secondary osteons where bone is redeveloped as well (e.g. MHNG GEPI V2567a), so this isn't a real difference between these taxa.  While Camp wrote "a projection of the borders would indicate an original total length of at least 90 mm" for the tooth, he also repeated Osborn's 1906 statement that Tyrannosaurus (CM 9380 and NHMUK R7994) teeth are up to 125 mm, which includes the root.  Combined with his statement the serrated distal carina "reaches the base of the enamel" and serrations are not illustrated on the most basal section, the actual crown length would have been about 69 mm.  Similarly, Camp wrote "At the base it is 17 mm. in longest diameter", but scaling the figured tooth to the stated preserved length of 60 mm results in a FABL of 22 mm instead.  Young (1942) later wrote "The general structure of [Szechuanosaurus campi syntype] V236 with the way of serrations fits so well with the Junghsien tooth, we feel that there is practically no doubt in regarding them as identical" "and prefer to consider the Junghsien tooth as belonging also to the new form" Szechuanosaurus.  This despite previously stating UCMP 32102 "is bigger and straighter than all" Szechuanosaurus syntype teeth.  Compared to Sinraptor dongi and Szechuanosaurus, UCMP 32102 is larger (~69 vs. up to 63 vs. ~32 and ~47 mm), with a much greater crown height/base ratio (~314% vs. up to 244% vs. ~224% and ~267%), making it less tapered.  The crown section is similar to Allosaurus' fourth dentary tooth and the mid crown ratio of 53% is similar to dentary teeth in S. dongi and between S. campi IVPP V238B and 238C.  As in mesial teeth of S. dongi, the crown is slightly lingually curved and the mesial carina does not reach the crown base.  The same serration densities (mesial 15 per 5 mm, distal 6.7-10 per 5 mm) can be found in S. dongi as well, but are lower than S. campi (distal ~12-19 per 5 mm).  Dong et al. (1983) wrote "Camp's description and the dentition size suggests it may be assignable to Yangchuanosaurus", but it is larger than even the magnus type (up to 75 mm), and more elongate than the largest maxillary teeth of the genotype (crown height/base ratio of 267%), but detailed dental statistics of the genus have yet to be published.  The femoral fragment is notably large, Camp stating the shaft has "an enormous hollow cavity about 125 mm. in the longest diameter of its ellipse. The greatest diameter of this segment at its narrowest point is 20 cm."  Based on the absence of a fourth trochanter or medial narrowing, the section is just distal to the former structure.  Here large theropod femoral shafts are wider than deep, so 200 mm would be the width and the figured depth is then ~143 mm.  Scaling from the largest metriacanthosaurid, Yangchuanosaurus magnus, results in a femoral length of ~1.33 meters, not far from Camp's "estimated total length of about 140 cm."  The ischium "consists of a moderately hollow shaft spreading into a broader, solid plate", which could describe most non-maniraptoran ischia, while the "tip of a large rib" is not described.  Notably, the ischium was found 37 meters from the other material, so its association is less certain.
Given the above information, UCMP 32102 is different from the Szechuanosaurus syntypes and anteriorly straighter than Sinraptor as well, and is perhaps the largest known Jurassic theropod.  As no characters are outside the range of ceratosaurids, it is considered Averostra incertae sedis here.
References- Camp, 1935. Dinosaur remains from the province of Szechuan. University of California Publications, Bulletin of the Department of Geological Sciences. 23(14), 467-471.
Louderback, 1935. The stratigraphic relations of the Jung Hsien fossil dinosaur in Szechuan red beds of China. University of California Publications. Bulletin of the Department of Geological Sciences. 23(14), 459-466.
Young, 1937. New Triassic and Cretaceous reptiles in China (With some remarks concerning the Cenozoic of China). Bulletin of the Geological Society of China. 17(1), 109-120.
Young, 1942. Fossil vertebrates from Kuangyuan, N. Szechuan, China. Bulletin of the Geological Society of China. 22(3-4), 293-309.
Young, Bien and Mi, 1943. Some geologic problems of the Tsinling. Bulletin of the Geological Society of China. 23(1-2), 15-34.
Dong, Zhou and Zhang, 1983. Dinosaurs from the Jurassic of Sichuan. Palaeontologica Sinica. Whole Number 162, New Series C, 23, 136 pp.

UCMP 32102 tooth (top) and femoral shaft (bottom) (after Camp, 1935).

Finally, I've been translating He (1984), so here's that publication's supposed Szechuanosaurus-

unnamed Tetanurae (He, 1984)
Bathonian-Callovian, Middle Jurassic
Hexi Commune, Shangshaximiao Formation, Sichuan, China
Material- (CUT coll; = CCG coll) (multiple individuals) many teeth (~63 mm), anterior cervical centrum (~68 mm; immature; Fig. 6-16, Pl. X Fig. 3), mid cervical vertebra (~69 mm; Fig. 6-17), tenth cervical centrum (immature; Fig. 6-19a), ~second dorsal centrum (~55 mm; immature?; Pl. X Fig. 4), incomplete ~fourth dorsal vertebra (Fig. 6-19b), mid dorsal centrum (immature; Fig. 6-19c), more than forty caudal vertebrae including proximal caudal vertebra (Fig. 6-19d) and distal caudal vertebra (~70 mm; Pl. X Fig. 5), incomplete coracoid (~98 mm proximodistally), humerus (265 mm), ischium (~356 mm), femur, tibia (~730 mm), fibula (~709 mm) and unguals
Comments- He (1984) states that in 1964, 1979 and 1980 in Chengdu the institute (= CUT) "conducted systematic collections in Hexi Commune (near Huomu Station) in the suburbs of Qingyuan City, including many carnosaur specimens, including many teeth, cervical vertebrae, dorsal vertebrae, more than forty caudal vertebrae, complete ischium, femur, tibia and fibula, as well as relatively complete humerus, coracoid and claws." (translated)  He referred these to Szechuanosaurus campi because the syntypes were also found in the suburbs of Guangyuan and believed to be from the Shangshaximiao Formation based on faunal similarities and fossil abundance, "there is no significant difference in shape and size" between S. campi and the Hexi teeth, and "there is no evidence of the existence of two or more carnosaurs" from that horizon.  However, the teeth of S. campihave not been shown to be diagnostic within e.g. Metriacanthosauridae, multiple taxa with megalosaur-grade teeth are now known from the Shangshaximiao (Leshansaurus, Yangchuanosaurus shangyouensis, Sinraptor hepingensis), and S. campi itself may be from the Penglaizhen Formation or slightly lower Shuining Formation instead.  Furthermore, He notes "that the tooth size in this batch of Szechuanosaurus campi material we collected is quite varied, which means that in addition to the differences in individual size, there may also be immature specimens, because some vertebral centra and neural arches are unfused. The largest individual is comparable to the type of Yanchuanosaurus shangyouensis [sic], and the smallest individual is estimated to be only 4-5 meters in length."  Thus multiple individuals and perhaps multiple taxa are involved, with only the tibia and fibula in Plate X Figures 8-10 being claimed to be from one individual.  Note while Chure (2000) mentioned a metatarsal as being in this material, He does not indicate as such and Chure might have mistaken Plate X Figure 6 which is a humerus.  Indeed, Chure seems not to have translated the text so understates the preserved vertebral number and misses the reference to unguals.  Yang et al. (2021) later describe the humeral histology, noting their Szechuanosaurus specimen is from Hexi and citing He's paper.  This paper confirms the material "contains several incomplete individuals with large differences in size" (translated), that "The specimen is currently preserved in the Museum of Chengdu University of Technology" and that it was recovered from the Shangshaximiao Formation at the same locality as Mamenchisaurus "guangyuanensis".  "One of the medium-sized individuals was recovered, mounted and exhibited", which is photographed in their Figure 2, although it cannot be determined what material is real and what is plaster.
This material was originally referred to Megalosauridae by He (1984) based on tetanurine plesiomorphies (large teeth, short presacral vertebrae, distally expanded ischium), while Chure (2000) placed it in non-avetheropod Tetanurae based on the supposed lack of a posterodistal coracoid process and subglenoid fossa, although Figure 6-18 of He clearly shows both.  Although Chure believes the information available in the literature "make(s) it impossible to refer this material to any family" and considered it indeterminate, the figures and plates suggest otherwise.  Among Late Jurassic theropods, the slightly opisthocoelous cervicals are only known in piatnitzkysaurids and coelurosaurs, with the long and low neural spines being unlike most contemporary non-coelurosaur theropods, meaning the mid cervical vertebra at least is not megalosauroid or carnosaurian.  Similarly, the large coracoid tubercle is unlike basal tetanurines and more similar to ceratosaurs or coelurosaurs, although lacking the hypertrophied size of the former.  As suggested by Chure, the ischium does resemble Megalosaurus in the ventral kink of the shaft and boot morphology, although it is much more robust, thus a referral to Leshansaurus is plausible.  The tibia on the other hand is more similar to Sinraptor in the anteroposteriorly short proximal end and anteroposterior compression distally, so may be metriacanthosaurid.  Based on this brief comparison, the material deserves restudy and probably represents multiple tetanurine taxa.
References- He, 1984. The Vertebrate Fossils of Sichuan. Sichuan Scientific and Technical Publishing House, Chengdu, Sichuan. 168 pp.
Chure, 2000. A new species of Allosaurus from the Morrison Formation of Dinosaur National Monument (Utah-Colorado) and a revision of the theropod family Allosauridae. PhD thesis. Columbia University. 964 pp.
Yang, Liu and Zhang, 2021. The humeral diapophyseal histology and its biometric significance of Jurassic Szechuanosaurus campi (Theropoda, Megalosauridae) in Guangyuan City, Sichuan Province. Acta Geologica Sinica. 95(8), 2318-2332.

Tetanurae elements from He (1984)- 1, 2 teeth; 3 anterior cervical centrum; 4 ~second dorsal centrum; 5 distal caudal vertebra; 6 humerus; 7 ischium; 8 tibia in anterior and distal views; 9 fibula in lateral and distal views; 10 tibia and fibula in proximal view (after He, 1984).

Additional references- Siegwarth, Lindbeck, Redman, Southwell, unpublished. Giant carnivorous dinosaurs of the family Megalosauridae from the Late Jurassic Morrison Formation of eastern Wyoming. Contributions from the Tate Museum Collections, Casper, Wyoming. 2, 40 pp.

Benson, 2010b. The osteology of Magnosaurus nethercombensis (Dinosauria, Theropoda) from the Bajocian (Middle Jurassic) of the United Kingdom and a re-examination of the oldest records of tetanurans. Journal of Systematic Palaeontology. 8(1), 131-146.

Benson, 2010b (online 2009). A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society. 158(4), 882-935.