How not to redefine Ornithuromorpha

The answer is "any possible way."  As in, DON'T redefine Ornithuromorpha Chiappe et al. 1999, which has until now only been given two definitions, both node-based.  There's Chiappe's (2001) original "Patagopteryx + Vorona + Ornithurae" and his later (2002) more refined "Patagopteryx + Ornithurae", both based on the same topology, with a trichotomy between Patagopteryx, Vorona and Ornithurae.  Ornithurae in this case is Chiappe's version which was Hesperornis plus modern birds.

Yet in the description of their new bird Dingornis [edit] Dingavis longimaxilla (first mentioned in Wang et al., 2015), O'Connor et al. (2016) redefine Ornithuromorpha to be stem-based.  Their Ornithuromorpha is "The first ancestor of Neornithes that is not also an ancestor of the Enantiornithes, and all of its descendants."

Holotype of Dingavis longimaxilla IVPP V20284 (scale = 20 mm; after O'Connor et al., 2016).

First of all, will everyone PLEASE start paying attention to Phylocode Article 11.1- "All specifiers used in node-based and branch-based definitions of clade names, and one of the specifiers used in apomorphy-based definitions of clade names, are species or specimens."  Chiappe had the excuse that he was working over a decade ago.  But in 2016 that doesn't cut it.  And it's SO easy!  Just say "Passer domesticus < - Enantiornis leali".  Done!

Second, O'Connor et al.'s excuse is that "Although the proposed definition does not strictly equate with the published node-based definition, it does provide a formal definition for the current widespread usage of this term in most recent literature (Bell et al. 2010; O’Connor et al. 2010; S. Zhou et al. 2013a; M. Wang et al. 2015)."  Let's review those...
- Bell et al. (2010) in their description of Hollanda have Patagopteryx as the most basal taxon closer to modern birds than enantiornithines, so have no need for a different definition than Chiappe's and don't explicitly use one either.
- O'Connor et al. (2010) in their description of Longicrusavis have the same situation.
- Zhou et al. (2013) in their description of new Archaeorhynchus specimens don't even show a topology or mention Patagopteryx.  Notably, Zhou and Zhang (2006) in the original description of Archaeorhynchus just deleted Patagopteryx from the matrix they used without justification.  Why do you hate Patagopteryx so much, Zhou?
- Wang et al. (2015) in their description of new Gansus material do indeed place Ornithuromorpha in the wrong position, as they have Archaeorhynchus and Jianchangornis further from modern birds than Patagopteryx or Vorona, yet include them among Ornithuromorpha.  Note O'Connor was second author here.
So only one paper listed actually uses Ornithuromorpha as if it were a stem, and that shared a coauthor.  Hardly a convincing case that the usage is "widespread."  Sure there are other papers that use it this way, but almost all have O'Connor as a coauthor.  You don't get to use a name incorrectly tens of times and then say "looks like all the papers are using it this way, we better change it."

Third, by redefining names you're countering the entire point of phylogenetic nomenclature.  The beauty of the system is that regardless of your topology, you can apply clade names because their definitions stay constant.  Just find Passer and Ornithomimus in your tree and you'll always know where Maniraptora goes.  But if you pull a Sereno and declare Maniraptora to be "Oviraptor + Passer" instead, then your concept is no longer the same.  Ditto for Ornithuromorpha.

"Passer domesticus < - Enantiornis leali" is certainly a clade that deserves a name, but it's not the more exclusive Ornithuromorpha.  We didn't call the clade Ornithurae just because the BANDits got it wrong so often in the 90s, and we should aim to be better this time as well.



As an aside,  O'Connor et al. state "Although we do not consider [Gansus zheni] to be referable to Gansus, previously only known from the Xiagou Formation (You et al. 2006), we also recognize minor differences that suggest they are not referable to Iteravis huchzermeyeri."  After my in depth study, I'm skeptical.  Notably, O'Connor et al. did not add zheni to their matrix, although Iteravis emerged in a polytomy with Gansus. 
Is Dingavis from the same locality another synonym of Iteravis?  While it does seem to share the ventrally concave ischium with small mid dorsal process (also in Piscivoravis, Yanornis and Gansus), pedal digit IV is shorter (89% of III excluding unguals; compared to 99-110% in Iteravis), the ectethmoid (lacrimal of O'Connor et al.) is more acute, the carpometacarpus more elongated, and phalanx III-1 lacks the lateral process.  So offhand, I'd agree they're distinct.

References- Chiappe, 2001. Phylogenetic relationships among basal birds. In Gauthier and Gall (eds). New perspectives on the origin and early evolution of birds: Proceedings of the international symposium in honor of John H. Ostrom. Peabody Museum of Natural History. 125-139.

Chiappe, 2002. Basal bird phylogeny: Problems and solutions. In Chiappe and Witmer (eds). Mesozoic birds: Above the heads of dinosaurs. University of California Press. 448-472.

Zhou and Zhang, 2006. A beaked basal ornithurine bird (Aves, Ornithurae) from the Lower Cretaceous of China. Zoologica Scripta. 35, 363-373.

Bell, Chiappe, Erickson, Suzuki, Watabe, Barsbold and Tsogtbaatar, 2010. Description and ecologic analysis of Hollanda luceria, a Late Cretaceous bird from the Gobi Desert (Mongolia). Cretaceous Research. 31(1), 16-26.

O’Connor, Gao and Chiappe, 2010. A new ornithuromorph (Aves: Ornithothoraces) bird from the Jehol Group indicative of higher-level diversity. Journal of Vertebrate Paleontology. 30(2), 311-321.

Zhou, Zhou and O'Connor, 2013. Anatomy of the basal ornithuromorph bird Archaeorhynchus spathula from the Early Cretaceous of Liaoning, China. Journal of Vertebrate Paleontology. 33(1), 141-152.

Wang, Clarke and Huang, 2015. Ornithurine bird from the Early Cretaceous of China provide new evidence for the timing and pattern of the evolution of avian skull. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 233.


Wang, O'Connor, Li and You, 2015. New information on postcranial skeleton of the Early Cretaceous Gansus yumenensis (Aves: Ornithuromorpha), Historical Biology. DOI: 10.1080/08912963.2015.1006217

O'Connor, Wang and Hu, 2016. A new ornithuromorph (Aves) with an elongate rostrum from the Jehol Biota, and the early evolution of rostralization in birds. Journal of Systematic Palaeontology. DOI: 10.1080/14772019.2015.1129518

Chiappeavis is just another Pengornis

The last Mesozoic dinosaur named in 2015 is Chiappeavis magnapremaxillo (O'Connor et al., 2015b), electronically published on December 31st.  First of all, what a stupid species name.  Second, examination of the supposed diagnostic characters shows that like Parapengornis and IVPP V18632, it's just another example of Pengornis houi.  Which is a shame because Luis Chiappe really deserves a bird named after him.  So before anyone names a 'Chiappeornis', let's make sure it's a really distinctive specimen, okay?  It's also disappointing because O'Connor has an entire section of her thesis lamenting the fact so many enantiornithines are named without adequate diagnoses.  But here she's doing that herself (and yes, the contributions credit her with writing the manuscript).  I'll also note the paper lacks a measurement table and that Pengornithidae can be paraphyletic in their analysis depending on their assumptions (fig. S1E).  Anyway, let's look at the evidence...

Holotype of Chiappeavis magnapremaxillo STM 29-11 (after O'Connor et al., 2015).

Several characters were listed as supposedly diagnostic. The premaxilla was said to have a larger body and convex ventral margin, but the convex element has far too long of a ventral margin to be a premaxilla, so is more likely an incomplete maxilla with the base of the ascending process. The actual right premaxilla is then just the small anterodorsal portion right below the partially preserved left premaxilla, and has no visible ventral margin.

Left (top to bottom)- skull of Chiappeavis magnapremaxillo as seemingly interpreted by O'Connor et al. (2015b) (top), without interpretation (middle), and as interpreted by me (bottom) (after O'Connor et al., 2015b).  Right (top to bottom)- skulls of Parapengornis eurycaudatus holotype IVPP V18687 (top; after Hu et al., 2015), IVPP V18632 (middle; after Hu et al., 2014), and Pengornis houi holotype IVPP V15336 (after O'Connor and Chiappe, 2011).  Premaxilla colored red, maxilla colored blue, and nasal colored green.

The posterodorsal premaxillary process was claimed to be longer than other pengornithids, almost reaching the frontals. Yet this bone is highly abraded just posterior to figure 2A's 'l pm' label, so that this posterior portion could easily belong to the right nasal instead. This is bolstered by the fact it's the same width as the left nasal and that the right nasal is otherwise missing. These cranial reinterpretations also make far more sense as they match the morphology and preservation of other pengornithids, which would be expected as the postcrania are nearly identical.

The synsacrum has eight vertebrae (as in IVPP V18632; Parapengornis' is only partly preserved), while the authors claim Pengornis' holotype has seven. Yet the description of the latter says only that seven are visible, but that the anterior end is covered, and indeed there could easily be another one beneath the ilium. STM 29-15 (a Jiufotang pengornithid briefly described by O'Connor et al., 2015a) only has seven but is obviously younger based on its unfused sterna.

The "median trabeculae" of Chiappeavis are said to have concave lateral margins, but no such structure exists, so the authors clearly meant the posterolateral processes. Their slight lateral concavity is also seen in Parapengornis' holotype though not in STM 29-15 and perhaps IVPP V18632 (difficult to determine from the low resolution figure of the latter), while Pengornis' holotype doesn't preserve the sternum. [Edit] O'Connor cordially informed me she meant the posteromedian process, so incorrectly pluralized the term instead of my assumption that she used the wrong positional adjective ("median trabeculae is totally a valid term MORON - they fuse into xiphial region. check Baumel bitch" as per O'Connor pers. comm., 1-16-2016).  However, concave lateral edges on the posteromedian process are also present in IVPP V18632, absent in STM 29-15, and unknown in both Pengornis and Parapengornis. So this doesn't support Chiappeavis' validity either.

Sternum of Parapengornis eurycaudatus holotype IVPP V18687 showing concave lateral edge of posterolateral process (right edge of teal line) and [see discussion above] low posteromedian angle (purple lines) (after Hu et al., 2015).

The posteromedian angle of the sternum is said to be narrow, but while its 53 degree angle is a bit less than IVPP V18632's (at 68) or STM 29-15's (at 66), Parapengornis' holotype could have an identical angle if complete, and again Pengornis' holotype doesn't preserve the element.

Finally, the authors claim the proximal articular surface of the tibia is laterodistally inclined, but this is only true of the left tibia, with the right tibia having a right angle between the surface and the long axis of the bone. Furthermore, Pengornis' holotype and IVPP V18632 both have inclined surfaces, though Parapengornis' holotype lacks them. Given the variation in Chiappeavis' holotype, the variation is likely due to perspective or taphonomy.

Tibiotarsi of (left to right; flipped if necessary so that lateral is to the left) both of Pengornis houi holotype IVPP V15336 (after Zhou et al., 2008), right of IVPP V18632 (after Hu et al., 2014; left is in medial view), both of Parapengornis eurycaudatus holotype IVPP V18687 (after Hu et al., 2015), left of STM 29-15 (after O'Connor et al., 2015a; right is fragmented); and Chiappeavis magnapremaxillo holotype STM 29-11 (aftter O'Connor et al., 2015b).  Angle of proximal edge indicated in green; note that Chiappeavis' angles differ and that Pengornis' are both ventrolaterally angled.

Besides the characters listed in the diagnosis, O'Connor et al. note the short anterior cervicals are like the Parapengornis holotype but unlike Pengornis' holotype. As the latter is larger than the others, this may support ontogenetic cervical elongation.

They also correctly note the long pygostyle is like Pengornis' holotype, but unlike IVPP V18632 or Parapengornis' holotype.

Finally, the short metatarsal I is said to be like Pengornis' holotype, and is additionally like IVPP V18632 but unlike Parapengornis' holotype or STM 29-15. 

Thus the only real difference from Pengornis' holotype is the shorter anterior cervicals, and while there are a few differences from other pengornithid specimens (laterally concave posterolateral posteromedian sternal processes unlike STM 29-15 and (?)IVPP V18632; narrower posterior sternal angle than STM 29-15 and IVPP V18632; long pygostyle unlike STM 29-15, IVPP V18632 and Parapengornis' type; short metatarsal I unlike STM 29-15 and Parapengornis' type), there's no pattern of character distribution that would suggest separate pengornithid species (e.g. Parapengornis shares the cervical length, posterolateral process concavity and probably sternal angle, while IVPP V18632 is different in cervical length but shares metatarsal I length).  This is illustrated in the following table, showing the distribution of all real differences proposed to diagnose Jiufotang pengornithid taxa (known in more than two specimens) that aren't obviously ontogenetic- 

B- femoral length (mm) to indicate possible age.

C- robust base of maxillary ascending process.
D- low interclavicular angle.
E- metatarsal I short.
F- long anterior cervical vertebrae.
G- long pygostyle.
H- long posterodorsal lacrimal process.
I- laterally concave posterolateral posteromedian sternal process.
J- narrow posteromedian sternal angle.

Note the lack of a pattern unrelated to size.  Indeed, all but E, F and I correlate with size, and two of those conflict with each the other.  It's true that size is not fully correlated with osteological development in this series (e.g. STM 29-15 has unfused sternals unlike the slightly smaller IVPP V18632), but that's true of other taxa as well (e.g. Anchiornis, Archaeopteryx, Shenzhouraptor, Sapeornis, Archaeorhynchus).  So it's just like with Archaeopteryx and Microraptor- all specimens show uncorrelated differences, thus either every specimen is its own species or as far as we can tell they're a single species that shows variation.  Based on this I conclude all Jiufotang pengornithids should still be still retained in Pengornis houi.

References-  Zhou, Clarke and Zhang, 2008. Insight into diversity, body size and morphological evolution from the largest Early Cretaceous enantiornithine bird. Journal of Anatomy. 212, 565-577.
O'Connor and Chiappe, 2011. A revision of enantiornithine (Aves: Ornithothoraces) skull morphology. Journal of Systematic Palaeontology. 9(1), 135-157.
Hu, Zhou and O'Connor, 2014. A subadult specimen of Pengornis and character evolution in Enantiornithes. Vertebrata PalAsiatica. 52(1), 77-97.
Hu, O'Connor and Zhou, 2015a. A new species of Pengornithidae (Aves: Enantiornithes) from the Lower Cretaceous of China suggests a specialized scansorial habitat previously unknown in early birds. PLoS ONE. 10(6), e0126791.
O'Connor, Wang, Zheng, Hu, Zhang and Zhou, 2015b. An enantiornithine with a fan-shaped tail, and the evolution of the rectricial complex in early birds. Current Biology. http://dx.doi.org/10.1016/j.cub.2015.11.036
O'Connor, Zheng, Sullivan, Chuong, Wang, Li, Wang, Zhang and Zhou, 2015a. Evolution and functional significance of derived sternal ossification patterns in ornithothoracine birds. Journal of Evolutionary Biology. 28(8), 1550-1567.

Have a Stremmeia New Year!

To finish off the year, here's a taxon of ex-theropod not on anyone's dinosaur lists and which only gets 17 distinct Google results.  Perhaps you've heard of the 'Tendaguru Archaeopteryx', a supposed bird carpometacarpus from the Late Jurassic of Tanzania?  Well, as Molnar informed me over email, this was actually given a name by Nopcsa in 1930- Stremmeia scabra.  Its story follows...

Stremmeia Nopcsa, 1930
S. scabra Nopcsa, 1930
Tithonian, Late Jurassic
Upper Dinosaur Member of the Tendaguru Formation, Tanzania
Holotype- (HMN [edit- oh yeah, they changed the abbreviations] MB coll.) ?tibiale (24.5 mm) fused to ?fibulare (27.3)

Holotype of Stremmeia scabra (HMN coll.) in various views (after Stremme, 1919).

Comments- This specimen was discovered in 1910 associated with a Dicraeosaurus skeleton [edit- Stremme wrote the nonexistent combination 'Dicraeosaurus brancai' but specified skeleton S, so meant Brachiosaurus brancai] Giraffatitan's holotype, initially noted by Janensch (1914) as a bird carpometacarpus probably related to Archaeopteryx, then illustrated and described by Stremme (1919). The latter author could not determine what kind of reptile was represented, or if it was a metacarpus or metatarsus. Lambrecht (1933) noted that Stremme only mentioned Archaeopteryx in the context of differences between its metacarpus and the Tendaguru specimen, so dismissed Parkinson (1930) who stated Stremme considered them relatives. His own opinion was that the carpometacarpus resembled Rhea, so might indicate ratite relationships. Nopcsa (1930) meanwhile had identified the specimen as "carpals" of a pelobatid anuran, citing similarity to the tibiofibulare of Macropelobates (as noted by Stipanicic and Reig, 1957), and named it Stremmeia scabra. Among more recent authors, Hecht (1963) merely said that his reexamination of Stremmeia "showed that these bones are not frog remains" and Estes and Reig (1973) followed his interpretation. There has seemingly been no modern reevaluation of Stremmeia, or discussion of what its identity is if it is not a frog tibiofibulare.

Regardless of Hecht's comment, Stremmeia is more similar to e.g. Macropelobates' tibiofibulare than a maniraptoran carpometacarpus in the distinct proximal articular surfaces which form a flat outline instead of a single convex surface, and wide separation of the distal articular surfaces. This latter character is also unlike theropod metatarsals. However, the distal ends are more expanded transversely in anurans, and the distal articular surfaces seem to be simple instead of ginglymoid as in Stremmeia. Further differences from a coelurosaur manus include the large and quadrangular proximal surface of the shorter element (mcIII in most theropods) and sigmoid shape in side view. Whatever Stremmeia turns out to be, it is not theropod. Does anyone have another idea?

From left to right- carpometacarpi of Confuciusornis sanctus (Bonn specimen; after Goernemann, 1999) and Anchiornis huxleyi (holotype IVPP V14378; after Xu et al., 2008); metacarpals II and III of Archaeopteryx lithographica (Eichstatt specimen JM SoS 2257; after Wellnhofer, 1974); Stremmeia scabra (holotype HMN coll.; after Stremme, 1919); and tibiofibulare of Macropelobates osborni (holotype AMNH 6252; after Noble 1924).

References- Janensch, 1914. Ubersicht uber die Wirbeltierfauna der Tendaguru-Schichten. Archiv fur Biontologie. 3, 81-110.
Stremme, 1919. Uber die durch Bandverknocherung hervorgerufene proximale Verschmelzung zweier Mittelhand - oder Mittelfussknochen eines Reptils. Wissenschaftliche Ergebnisse der Tendaguru-Expedition. Archiv fur Biontologie. 4, 143-144.
Noble, 1924. A new spadefoot toad from the Oligocene of Mongolia with a summary of the evolution of the Pelobatidae. American Museum Novitates. 132, 15 pp.
Nopcsa, 1930. Notes on Stegocephalia and Amphibia. Proceedings of the Zoological Society of London. 1930, 979-995.
Parkinson, 1930. The dinosaur in East Africa: An account of the giant reptile beds of Tendaguru, Tanganyika territory. H.F. & G. Witherby. 192 pp.
Lambrecht, 1933. Handbuch der Palaeornithologie. Gebruder Borntraeger. 1024 pp.
Stipanicic and Reig, 1957. El "Complejo Porfírico de la Patagonia extraandina" y su fauna de anuros. Acta Geologica Lilloana. 1, 185-297.
Hecht, 1963. A reevaluation of the early history of the frogs. Part II. Systematic Zoology. 12(1), 20-35.
Estes and Reig, 1973. The early fossil record of frogs: A review of the evidence. In Vial (ed.). Evolutionary biology of the anurans: Contemporary research on major problems. University of Missouri Press. 11-63.
Wellnhofer, 1974. Das fünfte Skelettexemplar von Archaeopteryx. Palaeontographica. 147, 169-216.
Goernemann, 1999. Osteologie eines Exemplars von Confuciusornis aus der unteren Kreide von West-Liaoning, China. Archaeopteryx. 17, 41-54.
Xu, Zhao, Norell, Sullivan, Hone, Erickson, Wang, Han and Guo, 2008. A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin. Chinese Science Bulletin. 54(3), 430-435.

SVP 2015 Day 4

The final day.  Let's see what happened...

In another ornithischian abstract, Borinder et al. redescribe the hadrosaur Tanius.  As the authors state, it's been 86 years since the genus was described.  The only known specimen is immature and has a flexor canal on the femur.  Unfortunately, it emerges in a big polytomy with other taxa just outside Hadrosauridae.  I do wonder if excluding some of these nine taxa a posteriori might show some resolution between the remaining ones and Tanius.

Cranial elements of Tanius sinensis holotype (after Wiman, 1929).

Cuesta et al. argue that the ulnar bumps of Concavenator are homologous to the secondary remix attachment points of birds.  This was disputed separately by Naish and myself shortly after the genus was described.  I still don't see how the authors interpret the bumps as posterolateral instead of anterolateral.  I argued the structure was an intermuscular line between the flexor ulnaris and the extensor carpi radialis brevis (sensu Meers, 2003), or flexor digitorum profundus and extensor carpi ulnaris (sensu Gishlick, 2002).  Cuesta et al. state that (besides the triceps brachii which we both agree is back on the olecranon) they reconstructed the anconeus and abductor polices longus and that the bumps are not located between them.  The abductor polices longus (pronator quadratus in Meers) is a more proximodorsally located scar I agree has nothing to do with the bumps.  I think anconeus is another term for the extensor carpi ulnaris, based on Gishlick's figure of Corvus and Hudson and Lanzillotti's (1964) description.  So with the caveats that there seems to be no consensus for muscle names or homology between crocodylians and birds, I don't think Cuesta et al. had the same muscles in mind as I did.

Fortner reports "parts of an associated postcranial skeleton of a small theropod dinosaur recently collected from the uppermost Aguja Formation."  This is another frustrating example of the information-bereft abstract, with the first twelve lines devoted to introduction and background knowledge.  The only other bit of information is- "The specimen exhibits some unique features, but is compatible with identification as either Troodontidae or Dromaeosauridae."  This is very intriguing, as while both eudromaeosaur and troodontine teeth are known from the Aguja, we have Richardoestesia and Paronychodon from there too.  As I think these are microraptorine and basal troodontid respectively, this specimen could fit the bill.  Did anyone get more details?

The only published non-dental remains attributed to Paronychodon- a partial dentary IPFUB GUI D 1 in A. medial, B. dorsal, and C. lateral views (after Zinke and Rauhut, 1994).  It does differ from later Paronychodon in having distal and sometimes mesial serrations.

Harding et al. have the non-dinosaurian abstract I think could be most important to dinosaur studies.  They examined all "published characters for discriminating Sceloporus from the related iguanian lizards Uta and Urosaurus, and for discriminating among species of Sceloporus" for 14 species, "11 of [which] had more than ten individual skeletal specimens, and for four of them sample sizes exceeded 50 specimens."  Perhaps astonishingly "almost all characters published in the literature to identify fossil specimens have no power to discriminate reliably between Uta, Urosaurus, and Sceloporus, nor between species of Sceloporus we examined."  In our field where most species are only known from single specimens, and most known from multiple specimens don't have more than one or two described in detail, what does this mean for our autapomorphy lists?

Holtz et al. report more information on an Anzu specimen (anyone know the collection number?) they announced last year.  Interestingly, only distal tarsal IV is fused to the unfused metatarsus, and "a pair of pronounced cruciate ridges on the plantar surface of metatarsal III" are present as in Elmisaurus but don't extend as far proximally.  This would make it intermediate in pedal morphology between Chirostenotes and Elmisaurus. 

Maddin et al. present a hypothesis based on the development of skull roof bones in mice and chickens.  In mice (and axolotls) the suture between the frontal and parietal corresponds to the boundary between the neural crest and mesoderm in the embryo.  In chickens, the latter embryonic boundary is within the frontal itself.  Thus the authors suggest the avian 'frontal' is actually a fused frontal and parietal, while the avian 'parietal' is actually a postparietal.  They say that hypothesis "is also supported phylogenetically where data from the fossil record reveal separate frontal, parietal, and postparietal bones are present in all stem lineages of extant taxa, including that of birds (e.g., the stem archosaur Euparkeria)."  The problem I see is that the postparietal in basal archosauriforms is a tiny wedge between the parietals and supraoccipital, while the parietals have the same topological relationships and morphology in these basal archosauriforms that they do in basal dinosaurs.  It seems more likely to me that this is a case like manual homology where the developmental process itself evolves, so that somewhere on the sauropsid line, the neural crest-mesoderm boundary moved into the frontal.  Also interesting would be to know what the state in lepidosaurs and crocodylians is.

Comparison of skull roof in dorsal view of- left, Erythrosuchus africanus (after Gow, 2003); center, Ornithosuchus longidens (after Walker, 1964), and right, Herrerasaurus ischigualastensis (after Sereno and Novas, 1993).  Parietal is blue, postparietal is red.  Maddin et al. suggest the red at left is homologous to the blue at right.

Mannion et al. redescribe the famous 'French Bothriospondylus' (MNHN coll.), presumably based on Moine's (1999) thesis.  It's great that we're getting all of the historical Bothriospondylus material redescribed in the last decade.

McFeeters et al. do the important job of reevaluating Struthiomimus specimens.  Little known to most, the holotype is extremely fragmentary, with most information coming from Osborn's AMNH 5339, Nicholls and Russell's UCMZ 1980.1 and the new RTMP 90.26.1. The authors find "a relatively small partial skeleton from the lower Dinosaur Park Formation" (which based on listed elements must be ROM 1970) to belong to a new taxon of ornithomimid based on several autapomorphies.  This specimen forms the basis of the dorsal snout in Russel's (1972) and Paul's (1988) cranial reconstructions, making those composites.  Another specimen shares some pelvic characters with Qiupalong, perhaps relating to a Dinosaur Park astragalus reported by McFeeters et al. in last year's SVP abstract. 

Nesbitt et al. seem set to provide a detailed description of Asilisaurus, after the original tabloid announcement.  Interestingly, Agnosphitys is said to a basal silesaurid as well, which is the fourth proposed identification for the genus.  Add this to Agnolin's (2015) Jornadas Argentinas abstract proposing Pisanosaurus belongs to the clade, and its membership is expanding markedly.

We also get yet another description of Nothronychus' braincase.  Far be it for me to complain about having too many descriptions of a taxon, but this one specimen of one taxon was described in 2005, 2012 and 2013, and now we'll probably get a fourth portion next year or so.  At least this new abstract is about the previously unrecognized anterior portion, but I'd rather have that time and effort go towards... say "Zunityrannus" or describing the Bayan Shiree therizinosaur postcrania.  Smith et al. report that "there is a supraorbital evagination in this specimen that is currently interpreted as accommodating a well-developed nasal gland in the frontal.  This development has been observed in some other archosaurs, especially marine birds, where it is associated with salt excretion and is consistent with a beach or other evaporitic paleoenvironmental interpretation."  So let's all start our All Yesterdays style marine therizinosaur pics.

Finally for this year, Sullivan et al. report a 'sphenosuchian' specimen sister to Junggarsuchus.  This has the interesting mix of cursorial features with a webbed hand and distal tail sheathed with armor. 

References- Wiman, 1929. Die Kreide-Dinosaurier aus Shantung. Palaeontologia Sinica (series C). 6, 1-67.

Hudson and Lanzillotti, 1964. Muscles of the pectoral limb in galliform birds. The American Midland Naturalist. 71(1), 1-113.

Walker, 1964. Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs. Philosophical Transactions of the Royal Society of London, seies B. 248(744), 53-134.

Russell, 1972. Ostrich dinosaurs from the Late Cretaceous of western Canada. Canadian Journal of Earth Sciences. 9, 375-402.

Paul, 1988. Predatory Dinosaurs of the World. Simon & Schuster: New York. 464 pp. 

Sereno and Novas, 1993. The skull and neck of the basal theropod Herrerasaurus ischigualastensis. Journal of Vertebrate Paleontology. 13, 451-476.

Zinke and Rauhut, 1994. Small theropods (Dinosauria, Saurischia) from the Upper Jurassic and Lower Cretaceous of the Iberian Peninsula. Berliner Geowissenschaftliche Abhandlungen. E 13, 163-177.

Moine, 1999. Datation, condition de depot et position phylogenetique de 'Bothriospondylus madagascariensis' (Damparis,
Jura, France). MS thesis, Memoires de Maıtrise Magistere Sciences de la Terre ENS-Lyon.

Gishlick, 2002. The functional morphology of the forelimb of Deinonychus antirrhopus and its importance for the origin of avian flight. PhD thesis, Yale University. 142 pp.

Gower, 2003. Osteology of the early archosaurian reptile Erythrosuchus africanus Broom. Annals of the South African Museum. 110(1), 1-88.

Meers, 2003. Crocodylian forelimb musculature and its relevance to Archosauria. The Anatomical Record. Part A, 274A, 891-916.

Agnolin, 2015.  Nuevas observaciones sobre Pisanosaurus mertii Casamiquela, 1967 (Dinosauriformes) y sus implicancias taxonomicas. XXIX Jornadas Argentinas de Paleontologia de Vertebrados. Libros de Resumenes. 13-14.

SVP 2015 Day 3

Time for day three.  If I were in Dallas, I'd be waking up early for Technical Session X.

Carrano and Choiniere reexamine Ceratosaurus' forelimb based on the holotype.  The whole thing could use redescription since Gilmore's last one 95 years ago.  While they state "These new data are consistent with the placement of Ceratosaurus as close to (or within) Abelisauroidea", an abelisauroid Ceratosaurus is impossible as Ceratosauroidea predates Abelisauroidea, without even getting into phylogenetic nomenclature. 

Hey, we get more Dromiceiomimus feathers.  van der Reest et al. report on a new specimen preserving feathers on the proximal thigh and dorsal tail, but not ventral tail or distal hindlimb.  The feathers are also branched, moving this trait to the base of Maniraptoriformes.  As the feathers have rachis but lack barbules, it seems Prum's Stage IIIa was correct.

Segnosaurus galbinensis radius and ulna (paratype IGM 100/83), courtesy of Zanno.

Kobayashi et al. describe a new therizinosaur specimen from the Bayan Shiree Formation, where Segnosaurus, Erlikosaurus and Enigmosaurus come from.  While it's notable for having a reduced metacarpal III (and thus perhaps reduced third manual digit), none of the three named genera from that formation preserve enough manual material to evaluate their condition.  The new specimen is potentially comparable to Enigmosaurus and Segnosaurus in that all preserve the radius and ulna.

Funston and Currie report on their fairly complete Horseshoe Canyon caenagnathid.  Supposedly having cervicals "distinct from Epichirostenotes", an "articular ridge is intermediate in size and form between Caenagnathus collinsi" and sternbergi, and autapomorphic manual proportions, it should be useful for resolving caenagnathid taxonomy.  In addition to the expected anatomical details, ulnar "feather scars" are said to be present.

Lu et al. discuss the billionth new oviraptorid from the Nanxiong Formation.  This one's based on at least a skull and is similar to Khaan.  Some of these things have got to be synonymous

Saurornitholestes has been the ubiquitous but rarely described Late Cretaceous American dromaeosaurid.  We've had RTMP 88.121.39 and MOR 660 known since 1988 and 1990 respectively, but both are only mentioned in passing in papers.  Now we have a new almost complete specimen discovered in 2014 (did anyone who saw the talk catch the specimen number?) that includes a skull.  Is the Saurornitholestes osteology finally at hand?

Perhaps the most unusual theropod abstract is from Sorkin, describing a phylogeny for tetanurines.  I'm not sure if it's based on a quantitative analysis or just the noted 'key characters', but it's not similar to the current consensus.  From the abstract, his topology and taxonomy seems to be-

|--Ceratosauria
`--Tetanurae
   |--Spinosauridae
   |--Carcharodontosauridae
   `--+--Sinosaurus
      |--Piatnitzkysauridae
      |--Metriacanthosauridae
      |--Neovenator
      |--Megaraptora
      `--Avetheropoda
         |--Megalosauridae
         `--Euavetheropoda
            |--Monolophosaurus
            |--Acrocanthosauridae (incl. Eocarcharia)
            `--+--Allosauridae
               `--Coelurosauria

Brings you back to the early 90s, doesn't it?  Note the new clade name Euavetheropoda, said to be distinguished by a robust dorsal quadratojugal process.  In any case, the accepted phylogenetic definition for Avetheropoda would put it at the Allosauridae+Coelurosauria node, making Euavetheropoda unintuitively more inclusive. 

Wills describes sixteen teeth from the Bathonian Forest Marble Formation of England.  When analyzed, these plot with dromaeosaurids.  He states "This pushes back the origin of dromaeosaurids from the Kimmeridgian to the Bathonian", but Metcalf and Walker described teeth from the Bathonian Chipping Norton Formation of England as dromaseosaur-like back in 1994.  Maybe these new ones are more securely identified.

Dromaeosaurid-like tooth (GLRCM G.51422) from the Bathonian Chipping Norton Formation in lingual (A), labial (B) and basal (C) views (after Metcalf and Walker, 1994).

Just one more day to go, with quite a few interesting abstracts tomorrow.

Reference- Metcalf and Walker, 1994. A new Bathonian microvertebrate locality in the English Midlands. In Fraser and Sues (eds.). In the Shadow of the Dinosaurs- Mesozoic Small Tetrapods. Cambridge University Press. 322-332.

SVP 2015 Day 2

And we're on to day two.  Something I noticed about this year's and last year's abstracts is just how many of them are already published in official format by the time the meeting happens (yet another reason the embargo is silly).  I gather one of the big issues facing SVP is how many talks and papers there are, leading to greater expense, more parallel sessions, etc..  If the dinosaur abstracts are any indication, you could cut out a third of them by excluding those that will be published by September.

Pritchard created a new matrix to test the relationships of Sauria, but alas this is one of those abstracts that doesn't actually contain much information.  The most it says is that Protorosauria is para/polyphyletic, which everyone agrees with by now.  I would ask that if your SVP abstract is based on a phylogenetic analysis, please devote at least a couple sentences to describing the topology you found.  Otherwise it's just a tease and I learn nothing.

This was a great SVP for ornithischians.  We've had Arbour revise ankylosaurids, and now Burns is doing the same for Campanian-Maastrichtian North American nodosaurids. He finds Denversaurus is a valid taxon, sister to Panoplosaurus.  So that's another genus from your 1980s dino encyclopedias to dust off.

Denversaurus.  What?  That's not right?...

Continuing the ornithischian train, Barta and Norell report on new specimens of Haya.  The interesting thing here is that they performed two analyses- one with each specimen coded as a separate OTU, and the other with one Haya OTU that was coded as polymorphic when specimens differed.  In the first, Haya emerged as a basal thescelosaurid, but in the second it was a basal neornithischian.  This is presumably because PAUP/TNT finds it most parsimonious to choose a mix of states for the polymorphic characters that isn't found in any actual specimen.  It's concerning because being a lumper myself, I code e.g. Microraptor and Archaeopteryx as single OTUs.  Is that affecting their relationships in my analyses? 

Shelley et al.'s abstract is an example of two things I like.  First, figuring out where all of those extinct mammal groups go using a molecular scaffold for the topology.  Second, actually describing the results of the study- "Our phylogenetic analysis places "triisodontids" as a basal member of Euungulata within Laurasiatheria. "Triisodontidae" forms a paraphyletic stem of Mesonychia with Oxyclaenus most closely related to a monophyletic Mesonychia.  "Triisodontids" plus Mesonychia are closely related to a clade comprised of the arctocyonids Mimotricentes, Deuterogonodon and Chriacus."  Ahhh, actual information...

Besides the usual morass of Yixian and Jiufotang birds (including Parapengornis, which I think is just Pengornis), we get another specimen from the lower member of the Huajiying Formation.  This earlier horizon has otherwise only yielded Confuciusornis zhengi, Protopteryx, Eopengornis and Archaeornithura.  Hu et al.'s new enantiornithine is said to have a Liaoningornis-like sternum, which could cement the affinities of that genus. 

The Norman-Barrett team's on the basal ornithischian case again, this time with Baron et al.'s redescription of Lesothosaurus postcrania.  This is needed, as Sereno (1991) mostly described the skull and thus we've had to depend on Thulborn's work from 43 years ago.  They find Stormbergia to be based on older individuals of Lesothosaurus, which as a lumper, does not surprise me.  The genus emerges as a basal neornithischian.  This should be a good paper once it's published.

Holotype of "Morosaurus" agilis (USNM 5384) posterior skull and anterior cervicals in left lateral view (after Gilmore, 1907).

Finally, Whitlock and Wilson redescribe the hitherto enigmatic "Morosaurus" agilis.  Based on a braincase and anterior cervicals, it turns out to be a diplodocid.  While apparently not Apatosaurus (in which the abstract seems to include Brontosaurus) or Galeamopus, the newly exploded Morrison Diplodocidae leaves open numerous possible identifications- Supersaurus, Amphicoelias, Kaatedocus, Barosaurus, Diplodocus...  I'm not sure I believe its affinities can't be narrowed down further.  For instance, Lovelace et al. (2007) stated small cervical pleurocoels were diagnostic for Supersaurus, and agilis has large pleurocoels.  Tschopp and Mateus (2013) proposed numerous characters to distinguish Kaatedocus from other diplodocids, including a postorbitally restricted squamosal that agilis seems to have, and a postparietal foramen agilis seems to lack.  Maybe published characters have issues that I'm not aware of as a theropod worker, or maybe Gilmore's description is misleading, but I find hard to believe that something as complex as a braincase and posterior skull can't be distinguished between Kaatedocus and Diplodocus (even if Amphicoelias and Barosaurus can't be compared).

Join me again tomorrow, when we open with those sweet, sweet theropod abstracts...


References- Gilmore, 1907. The type of the Jurassic reptile Morosaurus agilis redescribed, with a note on Camptosaurus. Proceedings of the United States National Museum. 32(1519), 151-165.

Sereno, 1991. Lesothosaurus, "fabrosaurids," and the early evolution of Ornithischia. Journal of Vertebrate Paleontology. 11(2), 168-197.

Lovelace, Hartman and Wahl, 2007. Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional Rio de Janeiro. 65, 527-544.

Tschopp and Mateus, 2013. The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs. Journal of Systematic Palaeontology. 11, 853-888.

SVP 2015 Day 1

While again too poor to attend SVP, I thought I would provide my thoughts on the abstracts that interest me like I did last year.  The abstracts book can be download free at this link.  When adding abstracts to the Database, I noticed an issue that's been constant throughout the years- the titles are in UPPERCASE.  This makes copying them useless, which means everyone citing abstracts has to rewrite them.  This can only lead to more typos and serves no obvious purpose since the titles are already bolded to distinguish them from the rest of the text.  Does anyone else agree they should have normal capitalization?

This year there are no less than three abstracts marked as WITHDRAWN.  One is by Egberts and concerns wearing gloves when handling specimens to prevent skin oils damaging the fossils.  Another is by Spindler, about a supposed Carboniferous therapsid specimen.  The third by Parsons and Parsons involves aerial forelimb motion in Bambiraptor and Deinonychus.  I wonder why these three abstracts didn't make it.

Wilson reports that of three histologically sampled Pteranodon specimens, the largest and smallest are rather mature, while the medium-sized one is immature.  While she interprets this to mean "there may be a large amount of adult body size variation in Pteranodon" or possibly that "the smallest specimen sampled is from a large Nyctosaurus specimen", Peters' idea of taxonomic instead of ontogenetic variation in Pteranodon seems viable too.  Is this a case of Peters being right?

Andres (and posthumously Langston) signal the beginning to the end of the deplorable situation pterosaur workers have been in where Quetzalcoatlus' holotype has been inaccessible due to the TMM embargoing it for decades.  All it took was the eventual death of the person monographing it.  :|  Now if we can just get Pelecanimimus out of the same rut, so that those who have the thesis describing it will distribute it and allow others to photograph the material described over two decades ago...

Frontals of Bellusaurus sui referred specimen IVPP V17768.7 (left; after Mo, 2013), Europasaurus holgeri referred specimen DFMMh/FV 162 (center; after Marpmann et al., 2015), and Camarasaurus lentus referred specimen CM 11338 (right; after Gilmore, 1925) showing two characters reported by Moore et al. as shared between the former two genera- elongate frontal and deep orbital concavity in frontal. 


Moore et al. report on new Bellusaurus cranial elements, juvenile like the previously known material.  Interestingly, these support a macronarian position, and close relationship with Europasaurus.  No update on the oft-hypothesized synonymy with Klamelisaurus, as that genus only preserves teeth and postcrania.

Finally, we have the abstract supposedly authored by Chinzorig, Kobayashi, Tsogtbaatar, Mahito, Rinchen and Shigeru...?  Someone messed up somewhere, because of course the actual authorship using surnames should be Tsogtbaatar, Kobayashi, Tsogtbaatar, Watabe, Barsbold and Suzuki.  This one's going to be tedious to find/cite in the future.  The find itself is a diagnostic ornithomimid tarsus and pes from the Djadokhta Formation of Mongolia, unfortunately not comparable to the previously described cranial and vertebral material (IGM 100/987 and 100/1245) from that formation.

Join me tomorrow for Day 2 talks and posters...

References- Gilmore, 1925. A nearly complete articulated skeleton of Camarasaurus, a saurischian dinosaur from the Dinosaur National Monument. Memoirs of the Carnegie Museum. 10, 347-384.

Mo, 2013. Bellusaurus sui. Topics in Chinese Dinosaur Paleontology. Henan Science and Technology Press. 155 pp.

Marpmann, Carballido, Sander and Knötschke, 2015. Cranial anatomy of the Late Jurassic dwarf sauropod Europasaurus holgeri (Dinosauria, Camarasauromorpha): Ontogenetic changes and size dimorphism. Journal of Systematic Palaeontology. 13(3), 221-263.