Wednesday, November 28, 2012

"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
- (PIN coll.) distal metatarsal II (~300-400 mm)
Late Barremian-Mid Aptian, Early Cretaceous
Mogoito Member of Murtoi Formation, Buryatia, Russia
- ? 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.

Saturday, November 24, 2012

"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 ( M. woodwardi has not been used as a valid name after 1899 (false, as Lydekker used it in 1909) and ( 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.

Friday, November 16, 2012

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 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.

Sunday, November 4, 2012

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.