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Coelophysoid theropods 101

The views expressed are those of the author and are not necessarily those of Scientific American.


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Due to the usual frustrating inability of being unable to finish any of the in-prep Tet Zoo articles (and… I’ve been away), I give you the following short article.

Life restoration of Coelophysis bauri (by Darren Naish), with detailed image of head at right (by John Conway). The larger scale bar goes for the whole animal; the smaller one for the head alone. CC BY.

Coelophysoids are best known for Coelophysis from the Upper Triassic of the USA; extremely similar (perhaps congeneric) forms are known from the Lower Jurassic of Zimbabwe, South Africa, China and Europe. These are gracile theropods, approximately 3 m long and less, with shallow, slender skulls where a subnarial gap is present between the posterior-most premaxillary teeth and first maxillary tooth.

Larger coelophysoids from the Late Triassic (including Gojirasaurus and Liliensternus) are 5-6 m long. Dilophosaurus from the Lower Jurassic of the USA and China (though read on) is also large at 7 m and is famous for its paired, semicircular cranial crests. These crests are extremely fragile and presumably served an exclusive role in visual display. The Chinese DilophosaurusD. sinensis (named in 1993) – was recently argued to be synonymous with the previously obscure Sinosaurus triassicus (named in 1948) (Xing et al. 2013) [image below by Ghedoghedo].

Reconstructed skeleton of Sinosaurus triassicus (= Dilophosaurus sinensis, apparently). Photo by Ghedoghedo, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

Inclusion of Dilophosaurus and related taxa – informally referred to as dilophosaurids – within Coelophysoidea has been questioned by some researchers since these animals are similar to tetanurans in a few details of cranial anatomy (Yates 2005). However, a coelophysoid clade that includes the dilophosaurids has been recovered in several studies. Coelophysoid monophyly is supported by the elongate, shallow proportions of the skull, subnarial gap, a deepened tip to the dentary, a proportionally large antorbital fenesta and other characters (Holtz 2000, Ezcurra & Novas 2006). Members of the group persisted to the end of the Early Jurassic.

Thorax of one of the famous AMNH Coelophysis specimens that has a crocodylomorph (NOT a juvenile Coelophysis) preserved within. Neck at top of image, left forelimb projecting to left. Image by smokeybjb, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

Skull and jaw anatomy, as well as body size, suggests that coelophysoids were mostly predators of small vertebrates. Stomach contents known for Coelophysis [adjacent image by Smokeybjb] were long thought to demonstrate cannibalism in this taxon but the fossils concerned are actually the remains of a small crocodylomorph (Nesbitt et al. 2006).

An especially intriguing aspect of the coelophysoid fossil record concerns the enormous aggregation of Coelophysis specimens known from Ghost Ranch, New Mexico. Why so many of these dinosaurs gathered in the same place, and then died together, is unknown: perhaps they were exploiting a super-abundant resource and died due to poisoning of some sort. Specimens of the bipedal rauisuchian Effigia and early theropod Daemonosaurus was also discovered within the Coelophysis mass death assemblage.

For previous Tet Zoo articles on Dilophosaurus and various other archaic theropods, see…

Refs – -

Ezcurra, M. D. & Novas, F. E. 2006. Phylogenetic relationships of the Triassic theropod Zupaysaurus rougieri from NW Argentina. Historical Biology 19, 35-72.

Holtz, T. R. 2000. A new phylogeny of the carnivorous dinosaurs. Gaia 15, 5-61.

Nesbitt, S. J., Turner, A. H., Erickson, G. M. & Norell, M. A. 2006. Prey choice and cannibalistic behaviour in the theropod Coelophysis. Biology Letters 2, 611-614.

Xing, L., Bell, P. R., Rothschild, B. M., Ran, H., Zhang, J., Dong, Z., Zhang, W. & Currie, P. J. 2013. Tooth loss and alveolar remodeling in Sinosaurus triassicus (Dinosauria: Theropoda) from the Lower Jurassic strata of the Lufeng Basin, China. Chinese Science Bulletin 58, 1931-1935.

Yates, A. M. 2005. A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods. Palaeontologica Africana 41, 105-122.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. THoltz 8:39 am 11/5/2013

    I actually provided a definition for Dilophosauridae Charig et Milner 1990 in the Complete Dinos 2.0: “Dilophosaurus wetherilli and all taxa sharing a more recent ancestor with it than with Coelophysis bauri, Ceratosaurus nasicornis, and Allosaurus fragilis” (p. 352).

    In the latest studies, this is simply a stem-group for with only Dilophosaurus is known.

    Link to this
  2. 2. AlHazen 1:29 pm 11/5/2013

    W.r.t. the specific name of Coelophysis bauri… who was Baur? Was he the same Baur that the therapsid Bauria is named for?

    (Even more tangentially… A literary scholar specializing in studies of the classics is called a “classicist”: are palaeontologists studying Triassic forms called “Triassicists,” or is specialization by period unlikely enough that the community has no need of a term for Triassic specialists?)

    Link to this
  3. 3. BrianL 1:38 pm 11/5/2013

    Is there any explanation why definite averostrans, the sister-group to coelophysoids, are so far unknown from the Triassic or lower Jurassic? Should we consider them simply not found yet, living in some non-fossiliferous localities during this timeframe or that coelophysoids are a paraphyletic grade from which averostrans evolved?

    Link to this
  4. 4. naishd 1:53 pm 11/5/2013

    Comment # 1: yeah, the idea of a dilophosaurid clade looked pretty likely at one point. However, future topologies may ‘regain’ the association at some point.

    Comment # 2: who was Baur? German-born comparative osteologist and dinosaur ankle expert George Hermann Carl Ludwig Baur. He worked as Marsh’s assistant for a while and this explains the patronym. Comparatively little known is that he worked during his later years on the evolution of the modern, island-endemic plants and animals of Fiji, the Solomon Islands and so on.

    Darren

    Link to this
  5. 5. naishd 1:56 pm 11/5/2013

    AlHazen (comment # 2): oh – and, yes, Bauria (and hence Bauriamorpha and so on) were also named for the same Baur.

    Darren

    Link to this
  6. 6. JoseD 2:36 pm 11/5/2013

    Naishd: “Stomach contents known for Coelophysis [adjacent image by Smokeybjb] were long thought to demonstrate cannibalism in this taxon but the fossils concerned are actually the remains of a small crocodylomorph (Nesbitt et al. 2006).”

    To be fair, there’s still evidence of Coelophysis cannibalism, including “intestinal contents” ( http://nmstatefossil.org/item/13 ).

    Link to this
  7. 7. David Marjanović 3:55 pm 11/5/2013

    German-born comparative osteologist and dinosaur ankle expert George Hermann Carl Ludwig Baur.

    Georg, then (pronounced roughly GAY-org).

    there’s still evidence of Coelophysis cannibalism, including “intestinal contents”

    I do wonder if these bones can be referred to anything smaller than Archosauria.

    Link to this
  8. 8. Halbred 5:46 pm 11/5/2013

    Isn’t Cryolophosaurus now among the coelophysoids?

    Link to this
  9. 9. Andreas Johansson 1:04 am 11/6/2013

    If D. sinensis = Sinosaurus triassicus, it would seem to follow that either this has to be considered allogeneric to wetherilli, or Dilophosaurus has to be sunk into Sinosaurus, right?

    Link to this
  10. 10. naishd 4:00 am 11/6/2013

    Halbred (comment # 8): Cryolophosaurus was considered a dilophosaurid for a while. Recent phylogenies, however, have found it to be closer to megalosauroids, allosauroids and coelurosaurs (the clade Orionides) than to Dilophosaurus (e.g., Carrano et al. 2012). This makes it an early member of the branch-based clade Tetanurae. Same goes for Sinosaurus.

    Darren

    Ref – -

    Carrano, M. T., Benson, R. B. J. & Sampson, S. D. 2012. The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10, 211–300.

    Link to this
  11. 11. BrianL 9:09 am 11/6/2013

    Okay, in that case ignore what I said about there being no known early Jurassic averostrans. But if we actually have tetanuraeans then, this only makes my question more pertinent: Where are the Triassic and lower Jurassic tetanuraeans and ceratosaurs?

    Link to this
  12. 12. naishd 9:48 am 11/6/2013

    BrianL: with ‘ceratosaurs’ in the Gauthieresque sense now forming a grade (a series of outgroups to Orionides), things aren’t that bad at all, since Sinosaurus and Cryolophosaurus are Lower Jurassic tetanurans. Berberosaurus, also from the Lower Jurassic, is a probable early member of Ceratosauria in the strict sense (the ceratosaurid + abelisauroid clade). However, given the origin of coelophysoids in the Triassic, there certainly should be ceratosaurians (s.s.) going back that far – they do, therefore, still have a Triassic ghost lineage.

    Darren

    Link to this
  13. 13. BrianL 11:44 am 11/6/2013

    Okay, seems like changes in theropod phylogeny have once again gone faster than my keeping up with them…or that my memory is losing ever more snippets of knowledge.

    I just looked up Orionides and have to say things haven’t changed as much as I feared. Still, I can’t help but wonder how many more Sibbick-produced plates a modern version of Norman’s ‘The Illustrated Encyclopedia of Dinosaurs’ would have to include to cover non-avian dinosaur diversity adequately. Oh, the days when you could simply include sections called ‘Carnosaurs’ and ‘Coelurosaurs’ and be up to date and thorough! :)

    Link to this
  14. 14. John Harshman 8:43 pm 11/6/2013

    What a tragedy for science that the name “Gojirasaurus has been attached to a fairly small (by tyrannosaurid or carcharodontosaurid standards) theropod, and a nomen dubium at that. What were they thinking? What’s worse, there seems no evidence for atomic fire breath.

    Link to this
  15. 15. Therizinosaurus 10:24 pm 11/6/2013

    Regarding the dilophosaur grade, this is another case where just taking the newest study’s result as the best idea is misleading.

    So when Holtz says “In the latest studies, [Dilophosauridae] is simply a stem-group for with only Dilophosaurus is known”, if he means Carrano et al.’s (2012) tetanurine analysis, this isn’t great evidence. The same goes for Naish’s comment #10 on Cryolophosaurus and triassicus in this analysis. Carrano et al. concentrated on tetanurine characters and taxa, so were not a good test of dilophosaur relationships or monophyly. Any useful test would at least want-
    1. Zupaysaurus and Liliensternus for coelophysoid diversity intermediate between dilophosaurs and coelophysids, and Dracovenator as another dilophosaur;
    2. more/complete basal ceratosaurs like Limusaurus and Eoabelisaurus to better determine the ancestral neotheropod condition; and
    3. non-avepods more relevant than Herrerasaurus and Eoraptor (e.g. Tawa, Eodromaeus, Daemonosaurus) to show which coelophysoid characters are primitive. Also,
    4. characters from coelophysoid-centric analyses like Tykoski (2005) and Ezcurra and Novas (2007).

    In addition to this issue of data sampling, the strength of Carrano et al.’s placements for these taxa are low. It only takes one more step to get Cryolophosaurus outside Ceratosauria+Tetanurae and 3 more steps to get triassicus there. So yes, these are most recently tetanurines, but only weakly supported as such, which could easily change if the characters and taxa mentioned above were added to the mix.

    As for Early Jurassic ‘averostrans’, there is also the tetanurine “Saltriosaurus”. Surely Naish misspoke at #12 about there needing to be Triassic ceratosaurians sensu stricto. Ceratosaurs and tetanurines both go back to the Early Jurassic and could have split then.

    Link to this
  16. 16. naishd 8:34 am 11/7/2013

    Mickey (comment # 15): remember that you (inadvertently) sound aggressive when referring to people you know by their surnames alone. Anyway…

    Yes, point taken that Carrano et al. (2012) was not a test of dilophosaurid monophyly, and that further study is still needed. I certainly did make the mistake of looking at recent published studies as if they represent current thoughts on this issue – which is fair enough, because they kind of do (err, publish or die and all that). Remember that Nesbitt et al. (2009), Sues et al.(2011), and Ezcurra & Brusatte (2011) included at least some of the respective taxa and also didn’t recover a dilophosaurid clade. I don’t think there’s an inclusive Dilophosauridae in the Cau megamatrix at the moment, either.

    As for what I said about there needing to be Triassic ceratosaurians (sensu stricto), yes, I was thinking of stem-averostrans: if dilophosaurids are coelophysoids, then the coelophysoid and averostran lineages should have split during the Late Triassic. Within Averostra, Ceratosauria (s.s.) and Orionides must have split by the Sinemurian… in which case the actual split may really have happened somewhat earlier, like in the Late Triassic.

    Darren

    Refs – -

    Ezcurra, M. D. & Brusatte, S. L. 2011. Taxonomic and phylogenetic reassessment of the early neotheropod dinosaur Camposaurus arizonensis from the Late Triassic of North America. Palaeontology 54, 763-772.

    Nesbitt, S. J., Smith, N.D., Irmis, R. B., Turner, A. H., Downs, A. & Norell, M. A. 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs. Science 326, 1530-1533.

    Sues, H.-D., Nesbitt, S.J., Berman, D. S. & Henrici, A. C. 2011. A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society B 278, 3459-3464.

    Link to this
  17. 17. ectodysplasin 8:55 am 11/7/2013

    @JohnHarshman;

    What a tragedy for science that the name “Gojirasaurus has been attached to a fairly small (by tyrannosaurid or carcharodontosaurid standards) theropod, and a nomen dubium at that. What were they thinking?

    Ken Carpenter, who named that specimen, is a huge, huge, huge Godzilla fan. There’s plenty of things you can criticize Ken on, but having respect for those films is not one of them.

    Link to this
  18. 18. THoltz 8:57 am 11/7/2013

    Yes, there are very few recent studies that recover a clade (in Coelophysoidea or closer to Averostra) comprised of a Dilophosauridae in my definition that aren’t just Dilophosaurus. However, there are studies underway by Ezcurra and by some other authors presented in recent SVP meetings that may find these.

    Also, there is presently no published information of the “saltriosaur” yet, and given that the primary evidence provided originally to say it was a tetanurine (e.g., the furcula) is now known to be in ceratosaurs and coelophysoids, I wouldn’t bet on it definitely being within Tetanurae.

    Link to this
  19. 19. Therizinosaurus 6:53 pm 11/7/2013

    Darren wrote- “remember that you (inadvertently) sound aggressive when referring to people you know by their surnames alone.”

    You know, I was thinking about that issue when writing the comment. I can see how it sounds aggressive, but I figured it’s also professional. Technical papers never refer to authors’ first names in the text, and the issues tackled here are often more technical than popular. But I can certainly start using first names here, as it is your blog.

    Nesbitt et al. (2009), Sues et al. (2011) and Ezcurra and Brusatte (2011) are all the same analysis. Sues et al. added Daemonosaurus and 4 characters to Nesbitt et al.’s, while Ezcurra et al. added Megapnosaurus, Camposaurus and 24 characters. Combined, the data are better at solving the dilophosaur problem than Carrano et al.’s in some ways and worse in others. It has Liliensternus, kayentakatae and Zupaysaurus, and plenty of non-avepods. But it’s far worse in the bird-ward direction, with Ceratosaurus the only ceratosaur, Piatnitzkysaurus, Allosaurus and Velociraptor the only tetanurines, and no sinensis. The characters also skew baseward, though are better for coelophysoids. Interestingly, Cryolophosaurus is further from ‘averostrans’ than Dilophosaurus is in Nesbitt et al. and Sues et al.. So while not a dilophosaurid, it’s not a tetanurine either. In Ezcurra and Brusatte’s tree, Dilophosaurus and Cryolophosaurus are in a polytomy (so could both be dilophosaurids), possibly because they didn’t keep Nesbitt et al.’s ordered characters ordered.

    If we make this analysis its best by adding Daemonosaurus to Ezcurra and Brusatte, code it for their 24 new characters, add Sues et al.’s 4 new characters and code them for Megapnosaurus and Camposaurus, and keep Nesbitt et al.’s ordered characters ordered (and make Ezcurra and Brusatte’s new multistate characters ordered when they should be), we get…

    Dilophosaurus and Cryolophosaurus in a polytomy with ‘Averostra’, so a dilophosaurid Cryolophosaurus is possible. Zupaysaurus is next most basal, and Liliensternus is in a polytomy with this clade and Coelophysoidea. Forcing Dilophosaurus and/or Cryolophosaurus to be a coelophysoids is only 3 steps longer. If Cryolophosaurus is one, it becomes a dilophosaurid with Zupaysaurus too. So I’d say this dataset is ambiguous for Dilophosauridae sensu lato, and only very weakly rejects coelophysoid dilophosaurs.

    Tom wrote- “Also, there is presently no published information of the “saltriosaur” yet, and given that the primary evidence provided originally to say it was a tetanurine (e.g., the furcula) is now known to be in ceratosaurs and coelophysoids, I wouldn’t bet on it definitely being within Tetanurae.”

    Fair enough, though Dal Sasso’s (2004) “Dinosaurs of Italy” does have technical photos and some information. If you use this and photographs of the material on display at the NHMM to add it to Carrano et al.’s matrix, it emerges as a tetanurine. Time will tell whether this holds once it’s officially described.

    Link to this
  20. 20. Halbred 7:05 pm 11/7/2013

    Hey, here’s a question:

    How many specimens of Dilophosaurus are there, and how many have preserved crests? A lot of these coelophysoid “grade” theropods have larger or smaller double-crests on the skull, and I wonder if it’s a sexually dimorphic trait.

    Link to this
  21. 21. Therizinosaurus 9:04 pm 11/7/2013

    Halbred- Considering only Kayenta Formation Dilophosaurus (D. wetherilli and specimens which might belong to related species, e.g. TMM 43646), there are five decent skeletons, and at least seven more individuals based on fragments. Of these, only two are complete enough to possibly preserve crests. The only one with well preserved crests is UCMP 77270, the intended holotype of D. “breedorum”, whose crests have only been described in Welles’/Pickering’s semi-published manuscript. The holotype UCMP 37302 also preserves bases of crests.

    The numbers, while low, seem against sexual dimorphism as 2 of 2 Dilophosaurus have crests, 1 of 1 Cryolophosaurus, and 4 of 4 sinensis. Zupaysaurus’ supposed crest is now known to be a displaced nasal (Ezcurra, 2007). The snout of juvenile Dracovenator lacks crests, though this may be ontogenetic. Among coelophysids, many Coelophysis and Megapnosaurus lack crests, and the one kayantakatae specimen well preserved enough has one.

    Link to this
  22. 22. naishd 7:04 am 11/8/2013

    In agreement with what Mickey just said, yes, sexual dimorphism is essentially absent in the cranial ornamentation of these theropods, so far as we can tell (and – remember – with respect to osteology alone). What does this mean? Some palaeontologists think that it demonstrate a non-sexual role for the structures: that they functioned as social signallers indicating membership of a given age class, social group (the ‘social selection’ hypothesis) or species (the ‘species recognition’ hypothesis). Others apparently hold out hope that strong sexual selection was present in life, it’s either that we’ve only discovered the members of just one sex (which isn’t impossible in some cases, given the sample sizes), or that we’ve made grave errors and have done stupid things like put males and females in different genera (Coelophysis is the male of Dilophosaurus, that sort of thing).

    Finally, others – including myself – have suggested that mutual sexual selection was at play: that males and females were similarly ornamented because members of both genders were displaying to conspecifics. This has been covered a fair bit at Tet Zoo before, see Dinosaurs and their ‘exaggerated structures’: species recognition aids, or sexual display devices? and Did dinosaurs and pterosaurs practise mutual sexual selection? I received some very, err, interesting communications about my work on mutual sexual selection at the recent SVP meeting…

    Darren

    Link to this
  23. 23. Yodelling Cyclist 8:45 am 11/8/2013

    *ahem* WHAT WERE THE CROCODILE SKULLS DARREN?

    Link to this
  24. 24. naishd 8:53 am 11/8/2013

    WOO-HOO, 23 comments!

    As for those crocodylian skulls… I DON’T YET KNOW WHAT THEY WERE, THAT’S WHY I HAVEN’T POSTED THE ANSWERS!! :)

    Darren

    Link to this
  25. 25. Yodelling Cyclist 8:56 am 11/8/2013

    Wa – seriously, you don’t know? Wow the Gods are mortal…

    Cheers anyway and congrats on the fish completion.

    Link to this
  26. 26. naishd 8:58 am 11/8/2013

    Well, actually, I >think< I know what they are – it's just that I've been trying to get it confirmed.

    Darren

    Link to this
  27. 27. Yodelling Cyclist 9:10 am 11/8/2013

    Has anyone heard anything out of Chatham island recently?

    Link to this
  28. 28. JoseD 11:59 am 11/8/2013

    David Marjanović: “I do wonder if these bones can be referred to anything smaller than Archosauria.”

    I don’t have access to the paper itself, but the abstract says, “Proximal metacarpals, an ulnare, and partial phalanges were prepared from the coprolite and are indistinguishable from those of C. bauri” ( http://nmstatefossil.org/item/43 ).

    Naishd: “I received some very, err, interesting communications about my work on mutual sexual selection at the recent SVP meeting…”

    Interesting enough for a future blog post (wink wink)?

    Link to this
  29. 29. David Marjanović 7:53 pm 11/10/2013

    However, given the origin of coelophysoids in the Triassic, there certainly should be ceratosaurians (s.s.) going back that far – they do, therefore, still have a Triassic ghost lineage.

    …Not if Ceratosauria and Tetanurae are sister-groups, right? Both show up in the Early Jurassic.

    What a tragedy for science that the name “Gojirasaurus has been attached to a fairly small (by tyrannosaurid or carcharodontosaurid standards) theropod

    It’s huge by Triassic theropod standards, and rather large by Triassic dinosaur standards in general.

    You know, I was thinking about that issue when writing the comment. I can see how it sounds aggressive, but I figured it’s also professional. Technical papers never refer to authors’ first names in the text

    That seems to be because they hardly ever refer to people, only to papers. First names do show up in the acknowledgments. Talking about people who are present in the same thread by last name only has a very 19th-century feel to it, my dear Watson.

    I don’t have access to the paper itself, but the abstract says, “Proximal metacarpals, an ulnare, and partial phalanges were prepared from the coprolite and are indistinguishable from those of C. bauri”

    Sure. The question is what else they’re indistinguishable from.

    Link to this
  30. 30. Yodelling Cyclist 6:17 am 11/11/2013

    My Dear Marjanovic,

    Personally I’ve always enjoyed a spot of antiquated formality.

    Yours
    Cyclist

    ( ;-) )

    Link to this
  31. 31. Raptormimus456 10:52 am 11/15/2013

    “If D. sinensis = Sinosaurus triassicus, it would seem to follow that either this has to be considered allogeneric to wetherilli, or Dilophosaurus has to be sunk into Sinosaurus, right?”~(comment #9)

    Well, if we were to sink it, Dilophosaurus would indeed be sunk with Sinosaurus, but what name retains it’s priority is up for debate; though Dilophosaurus is more likely to become a nomen conservandum then Sinosaurus, since it’s become more recognizable, even if Sinosaurus was named first.

    It’s the same scenario with T.rex and Manospondylus, even if Manospondylus was named first, T.rex supresses all synonyms by virtue of it’s status as a nomen conservandum.

    But, of course, “D.sinensis” is already a synonym of Sinosaurus, so it’s more likely the two will remain distinct genera, especially seeing as nobody has challenged the classification of Sinosaurus as a distinct genus to Dilophosaurus since 1948 when it was named, AFAIK.

    Link to this
  32. 32. Raptormimus456 10:54 am 11/15/2013

    And Darren, I see a distinct lack of feathers on that Coelophysis. Heresay to the Nth degree!!!1!

    And also; was it really so skinny? I though Coelophysis was a little more robust then that (unless, of course, that’s an illustration of the gracile form).

    Link to this
  33. 33. naishd 10:57 am 11/15/2013

    Ha ha – look again, the Coelophysis at top (my drawing) does in fact have a thin covering of fuzz (difficult to appreciate due to low resolution of image though). And, yes, I, for one, do think that these animals were that skinny. They really are insanely gracile.

    Darren

    Link to this
  34. 34. MMartyniuk 1:29 pm 11/30/2013

    Raptormimus456:
    Sounds like you may be a little confused regarding the synonymy situation. The type species of Dilophosaurus is D. Weatherilli, not D. Sinensis, which is a referred species. No matter what happens to sinensis, the name Dilophosaurus must always stay with weatherili. If sinensis is synonymous with triassicus, the name sinensis is sunk, but it transfers to a new genus – Sinosaurus. The old genus, Dilophosaurus, remains with its type species only.

    As for Tyrannosaurus, it is not a nomen consevandum. To become such requires a ruling by the iczn, which has never been sought. If Manospondylus gigas is a synonym of Tyrannosaurus rex, and it almost certainly is, it is the valid senior synonym unless somebody publishes a paper proving its a nomen oblitum. Which should have been done years ago, but enough people are content just ignoring Manospondylus and not bothering with bookkeeping minutiae. As a lover if bookkeeping minutiae, I’m puttering around with a draft paper sinking Manospondylus myself ;)

    Link to this

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