"Allosaurus/Chilantaisaurus" sibiricus is probably a megaraptoran

So the Database is still up for some reason, but I've come through with my promise to examine what Riabinin named Allosaurus sibiricus and which has been going by Molnar et al.'s reassignment as Chilantaisaurus sibiricus.  The description's in Russian (translations are welcome), but the holotype is figured clearly in all views, allowing us to make comparisons to other taxa (thanks to Molnar for sending it to me).  I can send the pdf to any who ask.

"Allosaurus" sibiricus Riabinin, 1915
= Antrodemus sibiricus (Riabinin, 1915) Huene, 1932
= Chilantaisaurus? sibiricus (Riabinin, 1915) Molnar, Kurzanov and Dong, 1990
Berraisian-Hauterivian, Early Cretaceous
Tignin Formation or Turgin Formation or Zugmar Formation, Chitinskaya Oblast, Russia
Holotype- (PIN coll.) distal metatarsal II (~300-400 mm)
Late Barremian-Mid Aptian, Early Cretaceous
Mogoito Member of Murtoi Formation, Buryatia, Russia
Referred- ? bone (Ivanov, 1940)
Diagnosis- (suggested) (combination of) metatarsal II lateral condyle with ventral surface width ~46% of condylar depth; metatarsal II medial condyle dorsal surface ~73% as wide as surface of lateral condyle and angled 35 degrees from lateral edge of lateral condyle.

Holotype of "Allosaurus" sibiricus, distal left metatarsal II in (top left to right) medial, dorsal, lateral, ventral, (bottom left to right) distal and proximal views (after Riabinin, 1915).  The distal end is 68 mm wide.

Comments- Note the description was actually published in 1915, though the volume was intended for 1914. The holotype was discovered in 1912 and deposited in what was then the Geological Museum of the Russian Academy of Sciences in Petrograd (Tolmachoff, 1924) (now St. Petersburg), which has since moved to Moscow. Riabinin (1915; partially translated in Chure, 2000) named it Allosaurus (?) sibiricus based on what he identified as a distal metatarsal IV. Huene (1932) said only that it did not permit exact characterization and probably belonged to an allosaurid (he renamed it Antrodemus? sibiricus as he thought that was a senior synonym of Allosaurus). Molnar et al. (1981) felt sibiricus resembled Ceratosaurus so closely that they "hesitate to accept it as an allosaurid". Molnar et al. (1990) on the other hand stated it was "almost identical with that of C. tashuikouensis in form and proportions of the distal condyle", so questionably referred it to Chilantaisaurus. Nessov (1995) agreed the species were similar and that sibiricus may belong in Chilantaisaurus. He noted stratigraphic data gave three possible formations the specimen was discovered in. Chure (2000) incorrectly said Riabinin did not illustrate the material, as he apparently had only a small portion of the original document. This error was repeated by Benson and Xu (2008). Chure excluded it from Allosauridae because he believed the distal outline was rectangular, but it is actually trapezoidal in both Allosaurus and sibiricus. Both Benson and Xu and Carrano et al. (2012) incorrectly credited Holtz et al. (2004) as being responsible for assigning it to Chilantaisaurus, though Carrano et al. correctly identified it as a second metatarsal. They believed it "too fragmentary to be assigned to a known taxon or identified as a distinct form" and noted similarity to Allosaurus, Neovenator, Torvosaurus and Afrovenator (though no metatarsal II has been reported for the latter).

Ivanov (1940) reported a bone referred to Allosaurus sibiricus from the Mortoi Formation, though without more data this referral is uncertain.

The holotype is ~70% the size of Chilantaisaurus tashuikouensis in distal width and depth, which would make it ~286 mm if similarly stout. If from an elongate metatarsus like Australovenator's though, it would be ~398 mm long. It differs from Allosaurus in having a more medially oriented dorsal curve to the lateral condyle, having a larger and more medially flaring medial condyle, having a lateral condyle which is recessed ventrally, and lacking the lateral flare on the ventral edge of Allosaurus' lateral condyle. Chilantaisaurus' medial condyle flares slightly more than Allosaurus' and it has a ventrally recessed lateral condyle, but it has the small medial condyle and a lateral flare like Allosaurus and has the dorsal curve oriented even further laterally. Of course, Riabinin and Molnar et al. were comparing sibiricus with the fourth metatarsals of Ceratosaurus, Allosaurus and Chilantaisaurus, not the second metatarsals (all three fourth metatarsals differ from sibiricus in having a ventrally pointed medial condyle and lacking a ventrally inset medial condyle, while Ceratosaurus' and  Allosaurus' element is much narrower, and Chilantaisaurus' has a larger dorsolateral bulge; Molnar et al. were correct that Chilantaisaurus' is more similar, but it is not almost identical). Taxa with similarly medially flaring medial condyles are Ceratosaurus, Torvosaurus, Sinraptor, Acrocanthosaurus, Fukuiraptor, Australovenator, Megaraptor and Harpymimus, though only Australovenator's and Acrocanthosaurus' are close in size. Taxa with a ventrally inset lateral margin are Rajasaurus, Megalosaurus, Chilantaisaurus, Fukuiraptor, Australovenator, Megaraptor, Appalachiosaurus and Alxasaurus.

Comparison of metatarsals in distal view (some reversed; scaled to equal depth). Top row, left to right- right metatarsal IV (medial to right) of Chilantaisaurus tashuikouensis (after Hu, 1964),  Allosaurus fragilis (after Madsen, 1976) and Ceratosaurus (after Gilmore, 1920).  Middle row, left to right- left metatarsal II (medial to left) of Chilantaisaurus tashiukouensis (after Benson and Xu, 2008), Allosaurus fragilis (after Madsen, 1976), Megaraptor (after Lamanna, 2004), "Allosaurus" sibiricus (after Riabinin, 1915), Australovenator (after Hocknull et al., 2009), Neovenator (after Brusatte et al., 2008), Torvosaurus (after Britt, 1991) and Alxasaurus (after Russell and Dong, 1994).  Bottom row, left to right- left metatarsal II (medial to left) of Ceratosaurus (after Gilmore, 1920), Rajasaurus (after Wilson et al., 2003), Megalosaurus (after Benson et al., 2010), Sinraptor (after Churrie and Zhao, 1994), Acrocanthosaurus (after Harris, 1998), Fukuiraptor (after Azuma and Currie, 2000), Appalachiosaurus (after Carr et al., 2005) and Harpymimus (after Kobayashi, 2004).

 Overall, it is most similar to Australovenator, differing in being 9% broader compared to depth, a broader lateral condyle ventrally, and having a more medially oriented dorsal surface of the lateral condyle. Next most similar is Megaraptor, which it differs from in having a broader lateral condyle ventrally with ventral surface angled more laterally, and a less rounded dorsal surface of the lateral condyle. The amount of ventral inset of the lateral condyle and dorsal exposure of the medial condyle is in between these two taxa. This suggests sibiricus may be a megaraptoran, which is congruent with its age, size and location. As it is intermediate in two variables, more similar to Megaraptor in depth, more similar to Australovenator in the orientation of the lateral condyle's ventral surface, and differs from both in the lateral condyle's ventral width, placing it in any named genus is not possible. As it does differ from all known theropod metatarsals, it is not a nomen dubium, contra Rauhut (2003), Holtz et al. and Carrano et al..

References- Riabinin, 1915. Zamtka o dinozavry ise Zabaykalya [A note on a dinosaur from the trans-Baikal region]. Trudy Geologichyeskago Muszeyah Imeni Petra Velikago Imperatorskoy Academiy Nauk. 8(5), 133-140.

Tolmachoff, 1924. On dinosaurs in northern Asia. American Journal of Science. 5(7), 489-490.

Huene, 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie. 4(1), viii + 361 pp.

Ivanov, 1940. [On the age of the coal-bearing deposits of Transbaikalia]. Sovietskaya Geologiya. 11, 45-54.

Molnar, Flannery and Rich, 1981. An allosaurid theropod dinosaur from the early Cretaceous of Victoria, Australia. Alcheringa. 5, 141-146.

Molnar, Kurzanov and Dong, 1990. Carnosauria. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria. Berkeley: University of California Press. 169-209.

Nessov, 1995. Dinozavri severnoi Yevrazii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii [Dinosaurs of northern Eurasia: new data about assemblages, ecology, and paleobiogeography]. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 156 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. Ph.D. thesis. Columbia University. 964 pp.

Rauhut, 2003. The interrelationships and evolution of basal theropod dinosaurs. Special Papers in Palaeontology. 69, 213 pp.

Holtz, Molnar and Currie, 2004. Basal Tetanurae. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria Second Edition. University of California Press. 71-110.

Benson and Xu, 2008. The anatomy and systematic position of the theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the Early Cretaceous of Alanshan, People’s Republic of China. Geological Magazine. 145(6), 778-789.

Carrano, Benson and Sampson, 2012. The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology. 10(2), 211-300.

"New" name for Megalosaurus? lydekkeri

When checking if Walgettosuchus woodwardi had in fact been reassigned to Megalosaurus as listed by Olshevsky (1991), I found a theropod name no one has noticed since its announcement.

Megalosaurus lydekkeri is a tooth first mentioned by Dawkins (in Huxley, 1869) as Megalosaurus, then called Zanclodon(?) sp. b. by Lydekker (1888), named Megalosaurus (gen. ?) lydekkeri by Huene (1926) and reassigned as Magnosaurus (?) lydekkeri by Huene (1932).  It's Early Jurassic, so probably not Megalosaurus or Magnosaurus, and has since been relegated to Theropoda indet. status and never compared in detail to anything.

Holotype tooth and maxillary or dentary fragment of Megalosaurus? woodwardi (BMNH 41352) (after Lydekker, 1888).

However, no one has noticed that in 1909, Lydekker designated the tooth as the type of a new species, Megalosaurus woodwardi (along with the tibia that would later be named Sarcosaurus andrewsi).  While he included no description or definition, he did provide an indication in the form of referencing Woodward (1908) who distinguished the tibia from M. bucklandii, Ceratosaurus and Allosaurus in its slenderness and "trochlear" shape of the astragalar facet, and from Triassic taxa in its tall astragalar ascending process.

Because Megalosaurus woodwardi has priority over Megalosaurus lydekkeri, but has not been used since it was named, ICZN Article 23.9.1 should be consulted to check if the former is a nomen oblitum. Usage of Megalosaurus lydekkeri must be maintained if (23.9.1.1) M. woodwardi has not been used as a valid name after 1899 (false, as Lydekker used it in 1909) and (23.9.1.2) M. lydekkeri has been used as a valid name "in at least 25 works, published by at least 10 authors in the immediately preceding 50 years and encompassing a span of not less than 10 years" (false as far as I can tell, as an extensive search located only 13-15 works since 1962*). Thus Megalosaurus woodwardi is the valid name, unless a worker were to petition the ICZN to suppress it.

* Neaverson (1962), Steel (1970), Kuhn (1972)?, Waldman (1974), Chure and McIntosh (1989), Molnar et al. (1990), Olshevsky (1991), Glut (1997), Carrano and Sampson (2004), Holtz et al. (2004), Naish and Martill (2007), Benson and Barrett (2009), Fastovsky and Weishampel (2009)?, Benson (2010), Carrano et al. (2012).

The ironic thing here is that the tibia has also been called Megalosaurus woodwardi, though for completely different reasons.  The specimen was accidentally made the type of two species simultaneously by Huene (1932) (Sarcosaurus andrewsi and Magnosaurus woodwardi). In that paper, Huene also lists Megalosaurus woodwardi in the section on Magnosaurus nethercombensis, stating both should be Megalosaurus subgenus Magnosaurus. As Magnosaurus is explicitly named as a new genus on that same page, this was probably an earlier opinion that was mistakenly retained. Note Huene uses "n. sp." and does not reference Lydekker's 1909 paper, suggesting he was not merely using Lydekker's name.  Though even if he did it wouldn't matter since Lydekker made the tooth the type, not the tibia.  The tibia is now called Sarcosaurus andrewsi because Huene was first revisor in 1956.

And in case you're wondering, I think Olshevsky was mistaken in thinking Walgettosuchus had been explicitly assigned to Megalosaurus as Megalosaurus woodwardi.

References- Huxley, 1869. On the upper jaw of Megalosaurus. Quarterly Journal of the Geological Society of London. 25, 311-314.

Lydekker, 1888. Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamta, Rhynchocephalia, and Proterosauria: British Museum of Natural History, London. 309 pp.

Woodward, 1908. Note on a megalosaurian tibia from the Lower Lias of Wilmcote, Warwickshire. Annals and Magazine of Natural History. 8(1), 257-259.

Lydekker, 1909. Vertebrate paleontology in 1908. Science Progress in the Twentieth Century: A Quarterly Journal of Scientific Work & Thought. 3(11), 450-471.

Huene, 1926 The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista Museo de La Plata, 29, 35-167.

Huene, 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte [The fossil reptile order Saurischia, their development and history]. Monographien zur Geologie und Palaeontologie, serie 1. 4(1-2), 1-361.

Huene, 1956. Paleontologie und Phylogenie der niederen Tetrapoden. Fischer-Verlag, Jena.

Olshevsky, 1991. A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings. 2, 196 pp.

Wang et al. 2012 - for once I'm against a paper synonymizing Jehol birds?!

Wang et al. have a new paper in press synonymizing Jixiangornis with Shenzhouraptor (their Jeholornis).

EDIT: I've been in communication with Dyke (who has been an exemplary scientist in his response) since posting this and it seems the paper was not supposed to be online yet and was taken down since Creisler's DML post http://dml.cmnh.org/2012Nov/msg00074.html so that more work could be done.  Gotta love the consequences of publishing submitted manuscripts early, and how things like this and Brontomerus' early surprise publication happened. ;)  Actually, the consequences here might be very good indeed....

Before I get into the meat of the paper, I'd like to express my continuing disappointment with how Yandangornis is handled by everyone, when it's mentioned at all.  Wang et al. claim Zhou and Zhang (2006) "reviewed Yandangornis longicaudus and concluded that it 'lacks the diagnostic characters of birds' and thus may also be a non-avian dinosaur".  In actuality, Zhou and Zhang merely said "Unfortunately, this fossil was only preliminarily described, showing no diagnosis of birds.  As a result, it remains a mystery whether it is a bird or bird-like dinosaur."  That counts as a review?!  Especially when Yandangornis was described as having numerous characters of basal ornithurine (sensu Gauthier) birds including the toothless upper jaw (with pointed symphysis), reduced number of caudal vertebrae (with rod-like distal caudals), fused sternum with median bulge, trochanteric crest, completely fused tibiotarsus, fibula not contacting tarsus and fused metatarsus.  I fear Yandangornis is becoming the Longisquama of birds- being curtly dismissed as an unknown factor without even trying to evaluate it.

On to the main topic.  Wang et al. present a new specimen of basal ornuthurine from the Yixian Formation, YFGP-yb2.  They claim this specimen combines characters of Shenzhouraptor and Jixiangornis, showing both to be synonymous.

First they say it has no maxillary teeth, unlike 'Jeholornis palmapenis' but like 'J. prima' and Jixiangornis (wouldn't this be itself a reason to separate the former species, if it were true and thus notable enough to comment on?).  Yet jeholornithid teeth are often unpreserved due to their small size and low number, as seen by palmapenis' lack of dentary teeth (considered preservational by O'Connor et al., 2010) and LPM 0193's (the Shenzhouraptor holotype) lack of any recognizable teeth. Even palmapenis only preserves one of the at least two maxillary teeth it had on that side. Thus the absence of maxillary teeth in other specimens may easily be preservational, so that Wang et al. simply accept reportedly absent teeth as such seems naive.

The scapula is said to narrow distally as in Shenzhouraptor, but this is true of almost all ornithurines including Jixiangornis, so means little.  The scapula was known to be curved in Jixiangornis previously (Nesbitt et al., 2009; and in Sapeornis), so that means little too.  The coracoid is correctly stated to be more elongate than Shenzhouraptor or Jixiangornis, which is interesting.  It's stated to be strut-like as in Jixiangornis (and by implication unlike Shenzhouraptor), but Jixiangornis has the less strut-like coracoid as can be seen in figure 82 of Turner et al. (2012).  Though Wang et al. claim the new specimen shares a well developed lateral coracoid process with Jixiangornis and not Shenzhouraptor, the latter has a better developed process than either (ironically making Wang et al.'s pairing right, but for the wrong reason).  [Edit: actually some individuals of both species have large processes, and some small ones] They claim the new specimen has the distal half of the medial coracoid margin convex as in Jixiangornis and unlike Shenzhouraptor, but in fact it differs from all prior specimens in having a completely concave medial margin distally.  The supposed furcula is said to be V-shaped and slender, so more like Shenzhouraptor, but what's identified is extremely slender like enantiornithines' and Jixiangornis' furcula is actually more V-shaped than Shenzhouraptor's (though nothing near this specimen's supposed anatomy).  Both would differ from the new specimen in lacking a large hypocleidium.  In fact, I'm nearly certain what Wang et al. think is a furcula is a dorsal rib and parts of dorsal vertebrae [Edit: I've since found the actual furcula under the coracoids].

Supposed furcula of basal ornithurine YFGP-yb2 (top) as photographed by Wang et al. (2012- figure 2A), (middle) as illustrated by Wang et al. (2012- figure 2B), (bottom) from an unpublished photo.

Wang et al. claim the new specimen is closer in radioulnar width ratio (claimed 50%) to Shenzhouraptor, citing a 50% ratio in 'Jeholornis prima', but Zhou and Zhang's (2002) figures show it closer to 65% in the latter.  Shenzhouraptor's holotype is ~71% and the new specimen's is ~64% based on an unpublished photo.  What's sad is that they cite Jixiangornis' ratio as "less than 0.7", basing this on a matrix coding by O'Connor et al., when Ji et al. (2002) explicitly listed widths in their forelimb measurement table (4.5 / 6.8 mm = 66%).  Did they not even read its original description?  Wang et al. claim the new specimen is more similar to Shenzhouraptor than Jixiangornis in lacking an intermetacarpal scar, saying it was "coded as potentially present in Jixiangornis by O’Connor et al.".  Potentially present?  Yuan (2005) and Turner et al. (2012) both code it as absent in Jixiangornis.  The new specimen (106%) supposedly resembles 'Jeholornis prima' (105-108%) more than Jixiangornis (104%) in its short manuohumeral ratio, but this isn't true.  And it's only a single percent difference anyway.  How is that important to note?  Annoyingly, this ratio isn't listed in the measurement comparisons table, nor is manual length, so you have to multiply the listed ulnohumeral and manuoulnar ratios to get it.  Shenzhouraptor's type has a ratio of 117% btw.  The ratio between manual unguals I and II is said to be more similar to Jixiangornis, with the new specimen having a larger ungual I, but the schematic drawing of Jixiangornis by Ji et al. (2002) would suggest it had a larger ungual II.  Shenzhouraptor has a larger ungual I, so is actually the taxon closest to the new specimen, but the schematic nature of Ji et al.'s drawing, small amount of difference in all specimens and difficult to separate claw sheaths makes any comparison unimportant.  The length of manual digit II is said to be more similar to Shenzhouraptor, but the ratio is identical to Jixiangornis (98% for II-1+II-2 / mcII). 

The high tibiofemoral ratio was suggested to be ontogenetic despite the smaller palmapenis type (which they cited earlier) having a larger ratio.  Wang et al. are wrong in claiming Jixiangornis has an incompletely fused tibiotarsus (Ji et al., 2002; Turner et al., 2012).  They claim the pedal unguals of 'Jeholornis prima' and the new specimen are more slender and less curved than Jixiangornis, but the opposite is true comparing Ji et al.'s illustration with figure 3 of Zhou and Zhang (2006), and the new specimen shows variation caused by keratin sheaths.

Wang et al. end with this paragraph, with my interjections bracketted- "To sum up, YFGP-yb2 shares the following features with Jeholornis prima that are absent in Jixiangornis: subequal manus and humerus lengths [untrue and a 1% difference]; similar ratio between the radius and ulna shaft widths [~1% difference]; and the absence of an intermetcarpal tubercle on metatarsal II [wow, the intermetAcarpal scar on metaCARPAL II, with the same mistake also in the abstract; in any case probably absent in Jixiangornis too]. YFGP-yb2 shares the following features with Jixiangornis that are absent in Jeholornis prima: large sized ungual [er, luckily we know this is manual ungual I from the discussion, but is probably untrue in Jixiangornis, difficult to evaluate in any specimen due to claw sheaths and is a small difference anyway] and coracoid with less convex medial margin [true, though the completely concave distal margin is unlike either of them] and less developed external process [true, though contradicting the earlier text Edit: false, as it varies in both species]."

Their discussion merely compares the new specimen, Jixiangornis and Shenzhouraptor with Zhou and Zhang's (2006) diagnosis for Jeholornis prima.  And yes, Zhou and Zhang used a lot of bad characters that are also found in Jixiangornis.  But what about Ji et al.'s diagnosis for Jixiangornis?  What about the differences noted by Yuan (2005), Turner (2008) and Nesbitt et al. (2009)?


This paper is flawed for so many reasons.  It presents incorrect data often.  Several times it contradicts itself, and has frequent grammatical and spelling errors.  The new specimen isn't even described, with only one photo and a schematic illustration.  Very odd features of the specimen aren't even noted- ~16 caudals [Edit: only the first twelve are preserved]; completely concave medial coracoid margin distally; only two non-ungual phalanges on manual digit III [Edit: it actually has three, which are interestingly twice the length of Shenzhouraptor's; the right digit III appears articulated but isn't]; subarctometatarsalian pes [Edit: not different from Shenzhouraptor or Jixiangornis] (the furcular morphology would be way too weird to pass by as well if it were real).  That whole furcular misidentification issue.  Many times facts are brought up that have no bearing on the synonymy issue, as when the new specimen resembles both taxa.  The main argument of the paper is because this specimen shows exclusive features of each taxon, those taxa are synonymous, yet these differences are often ~1% ratios and most proposed differences aren't even mentioned (dentary teeth; caudal count; fused sternum; stratigraphic level; just to take some mentioned by Ji et al., 2002).  There's no attempt to examine the literature for differences between each taxon, let alone the specimens.  The measurement table lacks both IVPP V13550 and palmapenis, not to mention the CAGS Jixiangornis specimen Turner (2008) and Nesbitt et al. (2009) used, and lacks one of the basic measurements mentioned in the text.  Perhaps most sad is they didn't even seem to read the original description of the taxon they're sinking, not citing its diagnosis and citing a matrix coding by someone else instead of a measurement explicitly listed in the description's Table 1.

Luckily, "This file will be reviewed by the authors and editors before the paper is published in its final form. Please note that during the production process errors may be discovered which could affect the content."  I'm sending this critique to the authors in hope that this paper is fixed before publication, though honestly fixing it destroys its entire point.  Are Shenzhouraptor and Jixiangornis synonyms?  This would require evaluation of over 50 supposed differences mentioned in the literature I noted above, but not by Wang et al..  In the meantime, I think YFGP-yb2 is certainly not Shenzhouraptor, and probably not Jixiangornis (may be a small adult?).  It makes for a more exciting paper in my opinion.

References- Ji, Ji, You, Zhang, Yuan, Ji, Li and Li, 2002. Discovery of an Avialae bird - Shenzhouraptor sinensis gen. et sp. nov. - from China. Geological Bulletin of China. 21(7), 363-369.
Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002. A new avialian bird - Jixiangornis orientalis gen. et sp. nov. - from the Lower Cretaceous of Western Liaoning, NE China. Journal of Nanjing University (Natural Sciences). 38(6), 723-736.
Zhou and Zhang, 2002. A long-tailed, seed-eating bird from the Early Cretaceous of China. Nature. 418, 405-409.
Zhou and Zhang, 2003. Jeholornis compared to Archaeopteryx, with a new understanding of the earliest avian evolution. Naturwissenschaften. 90, 220-225.
Yuan, 2005. Restudy on sapeornithids from the Lower Cretaceous of Yixian County, Liaoning. PhD Thesis. China University of Geosciences. 157 pp.
Zhou and Zhang, 2006. Mesozoic birds of China- A synoptic review. Vertebrata PalAsiatica. 44(1), 60-98.
Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis. Columbia University. 666 pp.
Nesbitt, Turner, Spaulding, Conrad and Norell, 2009. The theropod furcula. Journal of Morphology. 270, 856-879.
O'Connor, Sun, Xu, Wang and Zhou, 2012. A new species of Jeholornis with complete caudal integument. Historical Biology. 24(1), 29-41.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Wang, Dyke and Godefroit, in press. A new specimen of a Jeholornis-like long-tailed bird shows that Jixiangornis is a junior synonym of Jeholornis prima. Acta Palaeontologica Polonica. 14 pp. http://dx.doi.org/10.4202/app.2012.0051

The Theropod Database will be down for a while

Due to a recent move, my Comcast domain will be discontinued starting 11-4, so the Theropod Database will go offline then too.  Luckily, Nick Gardner has offered to host it, but I'll need to get my room and computer set up first, as all of the files are on there.  It should all be back up at a new address some time this week though.  The good news for all of you is that the newly uploaded version will be updated with many new taxa and studies from 2012, which were originally scheduled to go up in December.  The blog will not be affected, as it is hosted by Blogger.

In additional good news, once I'm set up for research again, we can figure out what Chilantaisaurus/Allosaurus/Antrodemus sibiricus is, because contra Chure, Riabinin (1914) did illustrate it.  In all six cardinal positions no less. I can tell you right now that it's not Chilantaisaurus though.

Did Dromiceiomimus really have long vaned secondaries?

For what will possibly be my last post before the big move (the blog will keep the same address, but we'll see how the Database itself is affected), Zelenitsky et al. (2012) recently reported a somewhat surprising discovery- wings in ornithomimids.

First, note it's not actually Ornithomimus edmontonicus the paper is about.  The supposed secondary shaft marks are from RTMP 95.110.1, which is Dromiceiomimus* samueli.  The other two, being from the Hoseshoe Canyon Formation, are probably D. brevitertius.  For some reason, everybody seems to want to ignore that edmontonicus was named in 1933, while brevitertius was named in 1926 and samueli in 1928.  Zelenitsky et al. follow Makovicky et al.'s (2004) Dinosauria II chapter which synonymized all of these species, but the name would still be brevitertius, not edmontonicus, as both published references state.  Principle of priority people!

 * Russell only placed edmontonicus in Ornithomimus because of its long metacarpal I, and Makovicky et al. did not list any additional justification. Yet O. velox has never been included in a published cladistic analysis as a separate OTU, and when it is (unpublished data), it does not clade with brevitertius (= edmontonicus) or samueli. For instance, O. velox lacks appressed metacarpals II and III and seems to have a medial distal condyle on metacarpal I positioned higher than its lateral condyle, both less similar to Dromiceiomimus than Anserimimus is.

With that out of the way, vaned feathers in ornithomimids shouldn't really be that surprising.  As Martyniuk (online 2012) stated, Currie and Chen (2001) noted Sinosauropteryx's seemingly stage 1 feathers were probably vaned, and there have been a few references since that discovered modern vaned feathers become difficult to diagnose as such after crushing and decay.  So the supposedly simple body feathers we have in e.g. Beipiaosaurus or Scuirumimus may have originally been vaned.  Pelecanimimus does have large paired sterna with ossified ribs and possibly uncinates, so maybe basal ornithomimosaurs were more flight-y anyway.  Not only that, but the seemingly solid position of ornithomimosaurs outside Oviraptorosauria+Paraves isn't quite as definite as it seems.  It's just that basically all recent coelurosaur matrices inherit the character bias and miscodings of the TWG matrix.  So no surprise their topologies are all similar.

I was however surprised that Horseshoe Canyon and Dinosaur Park specimens could preserve feathers.  The two Horseshoe Canyon specimens both show what have been commonly identified as stage 1 or 2 feathers, but which may be degraded state 3 feathers as noted above.  Those on the forelimb are short, but who knows how complete they are.  The Dinosaur Park specimen has been known for a while and is the source of the supposedly adult winged morphology described in the new paper.  This is based on black marks on the radius and ulna which trend posterodistally to distally, and sometimes are U- or hook-shaped as if they had hollow centers.  Now maybe these are feather remains, though I don't know of any other theropod which has preserved feathers this way.  Yet as Mcfeeters noted on the DML, they only show the shaft, not any vane.  Couldn't these just be stage 1 feathers, quills, etc.?  They certainly don't indicate Zelenitsky et al.'s conclusion that adults had long wing feathers while juveniles didn't, as the length is unknown in both (>15 mm in a juvenile; >6.5 mm in an adult).  Sure they're three times wider than the filaments of the juveniles, but the adult is 2.4 times as large, bases of feathers are thicker than other parts, and secondary quills are plausible without vanes.

So while the new paper is interesting in showing Dromiceiomimus had feathers and possibly thick quills/shafts on the lower arm in D. samueli, I don't think it successfully shows the genus had long secondaries, vaned secondaries, or changed its plumage ontogenetically.  This makes their oft-copied figure 4A/B of the little unwinged individual and adult with ostrich-like wings possibly misleading. 

References- Currie and Chen, 2001. Anatomy of Sinosauropteryx prima from Liaoning, northeastern China. Canadian Journal of Earth Science. 38, 1705-1727.

Makovicky, Kobayashi and Currie, 2004. Ornithomimosauria. In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 861 pp.

Martyniuk, 2012 online. http://dinogoss.blogspot.com/2012/08/did-sinosauropteryx-have-protofeathers.html 

McFeeters, 2012 online. http://dml.cmnh.org/2012Oct/msg00106.html

Zelenitsky, Therrien, Erickson, DeBuhr, Kobayashi, Eberth and Hadfield, 2012. Feathered non-avian dinosaurs from North America provide insight into wing origins. Science. 338(6106), 510-514.

Microraptor hanqingi and Senter's (2011) split

Hi readers.  I've been away due to the fun of unemployment and moving (which might shut down the Database for a short while), but here's a little something I did while deciding whether to make Microraptor/Cryptovolans multiple OTUs.  Though many species and specimens have been described, Senter et al. (2004) synonymized them, which was followed by Turner et al. (2012).  However, Senter (2011) recently reversed his opinion and has M. zhaoianus, the CAGS specimens (20-7-004 and 20-8-001 described by Hwang et al., 2002), M. gui and Cryptovolans all separate.  In addition, Gong et al. (2012) described a new species M. hanqingi which has yet to receive taxonomic commentary.

Senter states "recent personal examination of the holotype of M. zhaoianus (IVPP V 12330), a specimen referred to M. gui (IVPP V 13320), and a cast of the holotype of M. gui (IVPP V 13352) has revealed that the previous assertion that these taxa were synonymous (Senter et al. 2004) is incorrect.  These four OTUs differ from each other in too many character states to be considered synonymous (Table S1)."  Table S1 shows eight characters-

1. Lateral groove on maxillary and dentary teeth. Supposedly present in Cryptovolans but absent in the others.  Yet not only is this polymorphic in most theropods (check Currie et al.'s 1990 illustrations of Saurornitholestes, Dromaeosaurus, Richardoestesia and Troodon for instance), it is present in some teeth of the M. zhaoianus holotype, unpreserved in the M. gui holotype and CAGS 20-8-001, and is indeterminable in photos of CAGS 20-7-004's ~15 preserved teeth.

2. Serrations on maxillary and dentary teeth.  Supposedly present in Cryptovolans and the CAGS specimens (only preserved in 20-7-004) but absent in M. zhaoianus and M. gui.  This is actually present in M. zhaoianus' holotype (Xu et al., 2000) and referred specimen IVPP V13475 (Xu, 2002).  It is unpreserved in the M. gui holotype, though absent in referred specimen IVPP V13320.

3. Fusion of sternal plates.  Present in M. gui's holotype and both Cryptovolans specimens but absent in CAGS 20-8-001.  Unknown in CAGS 20-7-004 and unreported in the referred M. gui.

4. Manual phalanx I-1 significantly longer than metacarpal II.  Supposedly present in the CAGS specimens but not M. gui or Cryptovolans.  However, Hwang et al. state in CAGS 20-7-004 "Phalanx I-1 is very long; it extends almost as far as the distal articulations of metacarpals II and III."  It can be seen in figure 23 to be shorter than the incomplete metacarpal II, while the condition in CAGS 20-8-001 is unpreserved.

5. Manual phalanges II-1 and II-2 together longer than metacarpal II + carpus.  Supposedly present in Cryptovolans but absent in M. gui and the CAGS specimens.  Yet ignoring the carpus, Cryptovolans' paratype has a ratio of 91% and M. gui's holotype a ratio of 102%.  CAGS 20-7-004 has an incomplete metacarpal II so can only be said to have at least 95% and CAGS 20-8-001's ratio is unpreserved. 

6. Arching of first manual ungual.  Supposedly present in M. gui and the CAGS specimens but absent in Cryptovolans.  Yet this is impossible to determine in the Cryptovolans paratype due to the proximal portion of ungual being broken (the holotype's hands are impossible to evaluate in Czerkas et al.'s photos).

7. Strong lip on first manual ungual.  Supposedly present in M. gui and the CAGS specimens but absent in Cryptovolans.  Not only is this variable in other taxa (e.g. Archaeopteryx, Sapeornis, Confuciusornis), it is an illusion in Cryptovolans' paratype caused by the aforementioned broken proximal portion of that ungual.

8. Tibia bowed.  Supposedly present in Cryptovolans but absent in the others. Yet M. gui was originally diagnosed partially on having tibiotarsal bowing, though it is more developed in IVPP V13320 than the holotype.  M. zhaoianus' holotype is also stated to have a bowed tibia by Turner et al., which is true.  That of CAGS 20-8-001 is also bowed (Hwang et al., 2002 figure 28A).  The truth is most Microraptor specimens have some degree of bowing, and Turner et al. proposed the differences are largely taphonomic.

Note a recurring issue is that certain characters are only determinable in one specimen of a species, and there have been no valid characters proposed to e.g. group IVPP V13320 with the M. gui holotype, or group the CAGS specimens together to the exclusion of M. zhaoianus.  The only valid differences noted above are that referred M. gui IVPP V13320 lacks tooth serrations and CAGS 20-8-001 lacks sternal fusion.


Moving on to Microraptor hanqingi, Alexander et al. (2010) used LVH 0026 for their biomechanical work, considering it "probably a different species of Microraptor but is morphologically closely similar to M. gui, including the presence of flight-adapted feathers on the tarsometatarsus" (though remember M. zhaoianus' holotype merely doesn't preserve metatarsal remiges, and may have had them in life). Gong et al. (2012) later described it as the new species Microraptor hanqingi. They diagnosed it based on several characters-

"Largest known species of Microraptor; sternals not fused; robust pubis with squared distal end (more pointed in M. gui) and not as bent backwards as in M. gui; pubic boot tapering posteriorly; ischia with posterior edge straight and ventral edge concave while in M. gui they are sinuous and flat; differs from M. zhaoianus and resembles M. gui in having a proportionally short manual digit I; metatarsals II and IV about the same length (mt II slightly shorter); differs from M. gui in having fewer caudal vertebrae (23)."

The larger size (11-14% larger than M. gui or Cryptovolans) could be ontogenetic or individual variation. Unfused sternals are also present in CAGS 20-80-001 and NGMC 00-12-A, and vary within other species like "Ingenia" yanshini. The pubis is not more robust than in M. gui's holotype, and it cannot be determined if the pubic boot is more squared since most of M. gui's is hidden behind the tibiotarsus. The pubis is indeed bent ~10 degrees less than in the M. gui holotype, but some other specimens lack much bending at all (e.g. IVPP V13475). Contra Gong et al., the ischia of M. hanqingi are posteriorly sinuous and those of M. gui are anteriorly concave, so do not differ in these respects. Additionally, the short manual digit I (83% of mcII) was said to be like M. gui (87%) but unlike M. zhaoianus, and this is true for a referred M. zhaoianus IVPP V13475 (98%) and the Cryptovolans paratype (110%), while NGMC 00-12-A (85%) is also like M. hanqingi and M. gui.  The supposedly longer metatarsal II compared to IV was also supposed to be more similar to M. gui than to M. zhaoianus, but the latter's holotype has a ratio of 98% compared to 91% in M. gui's holotype. Other Microraptor specimens fall between those two ratios, and 7% differences or more are known in other coelurosaur species (e.g. Archaeopteryx lithographica and Dromiceiomimus brevitertius). Finally, its 23 caudal vertebrae are less than M. gui's ~26, but M. zhaoianus' holotype has 24, CAGS 20-7-004 and 20-8-001 have 26 and Cryptovolans has 28-30.  Other maniraptoriform species (e.g. Gallimimus bullatus and Shenzhouraptor sinensis) are known to have individual variation in caudal count within 3-4 vertebrae.

So besides the possibly ontogenetic large size, sternal fusion, pubic curvature, manual digit I length, metatarsal II/IV ratio and caudal number all vary compared to some other specimens.  Variation from other specimens is never significant (e.g. 10 degrees of pubic angle; 2% manual digit I length; one caudal centrum), often falls within the range of other specimens, and most are known to vary within other coelurosaur species.


In conclusion, the problem with splitting the Microraptor-Cryptovolans clade into species is not the absence of variation, as most of the described specimens have some proportions or characters which differ from all or most other specimens (see The Theropod Database's Microraptor entry for more examples, though it's not yet updated with this post's details). Instead, the problem is that these differences don't vary in a systematic, congruent way. While we might argue the Cryptovolans specimens and M. gui holotype should be grouped together to the exclusion of M. hanqingi, CAGS 20-80-001 and NGMC 00-12-A based on their fused sterna, we could equally as well argue the Cryptovolans specimens, M. hanqingi and NGMC 00-12-A should be grouped together to the exclusion of the M. gui holotype and CAGS 20-7-004 based on their long manual phalanx III-1. Or that Cryptovolans, M. hanqingi and CAGS 20-7-004 should be grouped together to the exclusion of the M. gui holotype and NGMC 00-12-A based on their long manual phalanx I-1. There is no obvious answer. One possibility would be to diagnose a separate species for each specimen, and indeed the variation may be due to several different species living in the Jiufotang fauna.  The more conservative approach taken by Senter et al. and Turner et al. is followed here, where differences are ascribed to individual and ontogenetic variation.


References- Xu, Zhou and Wang, 2000. The smallest known non-avian theropod dinosaur. Nature, 408, 705-708.
Czerkas, Zhang, Li and Li, 2002. Flying dromaeosaurs. in Czerkas (ed.). Feathered Dinosaurs and the Origin of Flight. 97-126.
Hwang, Norell, Qiang and Keqin, 2002. New specimens of Microraptor zhaoianus (Theropoda: Dromaeosauridae) from northeastern China. American Museum Novitates. 3381, 1-44.
Xu, 2002. Deinonychosaurian fossils from the Jehol Group of Western Liaoning and the coelurosaurian evolution. PhD Thesis. Chinese Academy of Sciences. 325 pp.
Senter, Barsbold, Britt and Burnham, 2004. Systematics and evolution of Dromaeosauridae. Bulletin of Gunma Museum of Natural History 8: 1-20.
Alexander, Gong, Martin, Burnham and Falk, 2010. Model tests of gliding with different hindwing configurations in the four-winged dromaeosaurid Microraptor gui. Proceedings of the National Academy of Sciences. DOI 10.1073/pnas.0911852107
Senter, 2011. Using creation science to demonstrate evolution 2: Morphological continuity within Dinosauria. Journal of Evolutionary Biology. 24, 2197-2216.
Gong, Martin, Burnham, Falk and Hou, 2012. A new species of Microraptor from the Jehol Biota of northeastern China. Palaeoworld. 21(2), 81-91.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.

Bennett's new paper with non-archosaurian pterosaurs

So you all know the basic history of pterosaur affinities.  Viewed as avemetatarsalians since the 1980s, this result has been found in basically every analysis.  Yet Peters (2000) argued they were actually related to non-archosauriforms like Longisquama, Cosesaurus and Sharovipteryx.  Indeed, he now thinks all of these taxa are lepidosauromorphs based on his analysis with too few characters, correlated characters and his ever un-trusty digital segregation technique of determining anatomy.  Peters rightly points out that no analysis has included the above three genera, many use suprageneric taxa, and most only examine archosaurs, so pterosaurs nesting with dinosaurs is an artifact.  Thus so far we have flawed analysis versus flawed analysis, so Bennett's new paper finding pterosaurs to be basal archosauriforms between proterosuchids and erythrosuchids has a chance to help.

Unfortunately, I don't think it does.  The basic premise is that Bennett is checking his 1996 analysis to see if hindlimb characters are causing pterosaurs and dinosaurs to clade together, and reviewing the cursorial characters (the Revised Data Set), then adding more characters and taxa (the Updated Data Set).  One thing I enjoyed about the paper is the speaking style, where Bennett goes against convention and speaks in the first person.  I also like the amount of discussion about coding choice and miscoding, which makes things more transparent.  As an example of both-

"I recently determined that the data set used in the analyses described in that paper differed from that in the published data matrix in that Scleromochlus was coded as 0 for Char. 43, whereas it was coded as missing in the published data matrix. From my present perspective, 14 years later, I cannot determine whether this was a typographical error or an intentional change during revision that was incompletely propagated through the manuscript, but here the published coding (i.e. – for missing) is used."

To cut to the chase, Bennett found the 14 cursorial characters were incongruent with other body areas and responsible for pterosaurs being avemetatarsalians.  Thus, "9 of 14 characters are found to be non-independent of other characters, functioning as inappropriate additional weighting of the underlying characters, and so are subsumed into the remaining characters as they are reformulated."  Once this was done, pterosaurs ended up as basal archosauriforms, with or without the new taxa and characters.

On the surface, this sounds great.  I was just complaining about correlated characters earlier.  But closer examination shows reason to worry.  Let's look at an example, character 112 from the 1996 analysis- "Bird-like distal end of femur – prominent anterior and posterior intercondylar grooves with latter constricted by prominent external tibial condyle. States: 0 = absent; 1 = present".  Well, that's pretty terrible in itself.  If I were to try to code Herrerasaurus for instance, it has a prominent posterior groove, but no anterior groove, and the lateral condyle doesn't constrict the posterior groove.  So we have a composite character that should be split into three.  Let's see how Bennett handles it.  He says-

"Comparison of the knees of ornithodirans sensu Gauthier reveals that they fall into two discrete types. [snip] Because of the presence of two discrete types of double condyle knees, the character needs to be reformulated:
Double condyle knee. States:
0 = absent;
1 = distal femur suboval, somewhat less than twice as broad transversely as long anteroposteriorly, with medial, lateral, and fibular condyles, and the posterior intercondylar groove constricted by the prominent external tibial condyle, proximal tibia and fibula not fused, and proximal tibia subtriangular and its anteroposterior length exceeds its transverse breadth;
2 = distal femur roughly D-shaped, roughly twice as broad transversely as long anteroposteriorly, with only two condyles and medial condyle considerably larger than lateral, posterior intercondylar groove not constricted, and the proximal tibia and fibula fused to form a suboval to subrectangular articular surface roughly twice as broad transversely as long anteroposteriorly,
with the coding as before except that the Pterosauria are coded 2. Because there is no evidence that one state evolved from the other, the character should be unordered for analysis."

That sound you just heard was the cladist in me choking and dying.  Bennett just made the character MORE composite.  In fact, I don't think I've ever seen such a composite character in my entire life.  I don't even know where to begin.  Herrerasaurus again, I suppose.  I guess the distal femur is kind of oval, but the front is flat.  Is that D-shaped as in 2, or does Bennett mean another side is flat in D-shaped femora?  It's 18% wider than deep, which is closer to "somewhat less than twice" than "roughly twice", but that state still doesn't sound right, nor are they quantified to help me if coding a femur e.g. 90% wider than deep.  It does have a fibular condyle, so that's like 1.  The posterior groove is unconstricted though, so that's like 2.  Also note state 1 doesn't define the comparative sizes of the medial and lateral condyles, though state 2 does.  The tibia and fibula are unfused, but what does that have to do with the femur?  It's quite the assumption that pterosaur tibiofibular fusion evolved at the same time as these other features.  The tibia is triangular because it has a cnemial crest.  It's longer than wide proximally, but state 2 compares that proportion in the tibia+fibula, so is not measuring the same thing.  It's not just that Herrerasaurus is some outlier either.  Heterodontosaurus lacks a posterior groove, but has a fibular condyle.  Scleromochlus lacks a cnemial crest, but also lacks tibiofibular fusion. Dromomeron romeri has a femur 71% wider than deep, but a tibia much longer than wide proximally.  This is why composite characters are terrible, and Bennett goes on to make equally horrible characters for the ankle and foot.  Note too that states 1 and 2 each contain plesiomorphic states that are shared with state 0, like the lack of tibiofibular fusion in state 1. 

But besides their terrible, terrible formation, what's really worrying about these characters is how they affect the analysis.  Bennett's basically taking characters that support avemetatarsalian pterosaurs (and in the case of ankle and foot characters, reducing their number), then combining them with perhaps functionally related but indepedent characters that differ between dinosaurs and pterosaurs, so that they can't group pterosaurs with avemetatarsalians.  You could do this with any character or set of characters.  Sure both caenagnathids and oviraptorids have a sliding mandible that lacks teeth and has a coronoid process, but oviraptorids have a mandible that's shorter, lacks symphyseal fusion, lacks the ASC complex, and has a surangular prong.  And I'm sure the sliding glenoid worked in conjunction with the coronoid process somehow and that it's related to their toothlessness.  Time to make that into two unordered states of a single character.  Ugh.  So Bennett eliminated most characters supporting avemetatarsalian pterosaurs and *gasp* didn't recover avemetatarsalian pterosaurs.

Just to round out my complaints, the characters were all ran unordered although many should be ordered (e.g. Parietal foramen. States: 0 = large; 1 = small; 2 = absent.).  Well, actually he states he ran the bistate characters as ordered, despite the fact ordering has no affect on bistate characters.  Also "most loss characters and a few gain characters (Char. 6, 14, 19, 20, 23–26, 28, 36, 41, 53–55, 68, 97, 118, 135, 136) were defined as irreversible".  I guess the humerus can never surround the median nerve and branchial artery again once the entepicondylar foramen is lost (24).  And hey, the antorbital fenestra can never be lost (41).  Who knew alligators were impossible?  In his Discussion, Bennett frankly admits his philosophical differences from most cladists-

"The general trend in phylogenetic analyses of diapsids has been towards analyses with more taxa and more
characters, as if more necessarily equated to better, and Nesbitt’s (2011) analysis is but the most recent. Unfortunately, the usual way to get more characters is to atomise the morphology of structures, coding for more and more insignificant features of structures, which leads to multiple unintentional weightings of the underlying character. Nesbitt’s analysis has 30 characters from the astragalus and calcaneum including, for example the shape of the anteromedial corner of the astragalus: acute or obtuse. It is absurd that the angle of the corner, a few degrees this way or that has the same weight in an analysis as the presence of an antorbital fenestra, a calcaneal tuber or a pteroid bone. I reject such atomisation of morphology, and point out again that most effort should go into formulation and testing of characters, rather than the analysis of the data and manipulation of trees and that one should use characters only if the ‘hypotheses of homology cannot be refuted’ (Gaffney et al. 1991)."

I wholeheartedly agree that we need to spend more time formulating and testing characters, but find the rest laughable.  First, there have been numerous papers showing adding taxa and characters usually results in a more accurate tree, though there are eventual limits to the payoff for both.  Bennett's 19 taxa and 144 characters is nowhere near those limits, needless to say.  What's truly absurd is that Bennett thinks he knows the angle of the anteromedial astragalar corner is less likely to change than the presence of an antorbital fenestra.  How would you even determine that?  Homoplasy?  Well, the corner character never converges or reverses in Nesbitt's matrix, so that can't be the reason.  The number of mutations it takes?  We have no clue about that, and given recent studies showing single genes can have huge phenotypic effects, I think it would be foolish to equate the apparent significance of a character with its phylogenetic worth.  The same issue surrounds his choice to make some characters irreversable.  How does he know which reversals are impossible genetically?  What Bennett is advocating is a return to the good ol' days of "key characters", or in this case key character complexes, which are even worse.

Oh, and Bennett doesn't include Longisquama, Cosesaurus or Sharovipteryx, instead adding two drepanosaurs and splitting Prolacertiformes into Prolacerta and Tanystropheus.  So he doesn't even really test Peters idea, since Peters has been saying since 2000 that those taxa are important for getting pterosaur affinities correct.  And of course he keeps Lepidosauromorpha as the outgroup, so Peters' new idea of lepidosauromorph pterosaurs isn't tested either.  Nor does it include important taxa like lagerpetids, silesaurids and Doswellia.  Bennett's analysis was fine in 1996, but doesn't cut it 16 years later.


So basically Bennett uses an outdated analysis, unfairly eliminates most characters supporting avemetatarsalian pterosaurs, doesn't include the best candidates for non-archosaurian pterosaurs, and espouses a horrible, subjective cladistic philosophy.  I'm still waiting for that good test of pterosaur relationships.



References- Peters, 2000. A reexamination of four prolacertiforms with implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia. 106(3), 293-336.

Bennett, 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined.  Historical Biology. iFirst article, 19 pp.