Theropoda is a term entrenched in the literature for carnivorous dinosaurs, but it's had competition over the years. Today we'll reflect on these alternative names for the group.
Cope (1866) named Goniopoda for Dryptosaurus (his Laelaps) and Streptospondylus (his Megalosaurus) based on his misinterpretation of their astragalus as the fibula, as a fibula which wraps distally around the tibia would be unique. The taxon was almost exclusively used by Cope through the 1880's, who eventually gave it a scope and diagnosis similar to Marsh's Theropoda (e.g. Cope, 1883). After Cope's death, Theropoda became the term exclusively used for carnivorous dinosaurs.
Harpagosauria was seen as a paraphyletic order of dinosaurs by Haeckel (1866), containing Megalosaurus, Plateosaurus and Pelorosaurus (but not Iguanodon). Haeckel refers to these as the carnivorous dinosaurs, which led Cope to synonymize the taxon with his Goniopoda (starting in 1870, and consistantly misspelled Harpagmosauria). However, Haeckel's original usage suggests it is instead the equivalent to Saurischia. Baur (1887) uses Harpagosauria as a dinosaurian group containing only Goniopoda, with Sauropoda separate. Haeckel (1895) later used Harpagosauria as a junior synonym for his new dinosaurian taxon Dysdracones including both Arctopoda (containing basal sauropodomorphs) and Theropoda, with sauropods now placed in his Eudracones that contained all herbivorous dinosaurs. Harpagosauria was said by Haeckel to contain the carnivorous dinosaurs with sharp teeth and claws. It has not been used since.
Proposed as part of a cladistic reclassification of ornithischians, Carnosauriformes was named by Cooper (1985) as a cohort of dinosaurs "retaining the primitive condition of recurved thecodontian dentition with finely serrated cutting edges." No justification for using this name over Theropoda was given, and it is today rightfully considered a junior synonym.
References- Cope, 1866. [On the anomalous relations existing between the tibia and fibula in certain of the Dinosauria]. Proceedings of the Academy of Natural Sciences of Philadelphia. 18, 316-317.
Haeckel, 1866. Generelle Morphologie der Organismen. Allgemeine Grundzuge der organischen Formen Wissenschaft, mechanisch begrundet durch die von Charles Darwin reformiete Deszendenz-Theorie. II. Allgemeine Entwicklungsgeschichte der Organismen. Kritische Grundzuge der mechanischen Wissenschaft von dan entstehenden Formen der Organismen, begrundet durch die Deszendenz-Theorie. Georg Reimer, Berlin. 462 pp.
Cope, 1870. Synopsis of the extinct Batrachia and Reptilia of North America. Transactions of the American Philosophical Society. 14, 1-252.
Cope, 1883. On the characters of the skull in the Hadrosauridae. Proceedings of the Philadelphia Academy of Natural Sciences. 35, 97-107.
Baur, 1887. On the phylogenetic arrangement of the Sauropsida. Journal of Morphology. 1, 93-104.
Haeckel, 1895. Systematische Phylogenie: Entwurf eines Natürlichen Systems der Organismen auf Grund ihrer Stammesgeschichte. Dritter Theil: Systematische Phylogenie der Wirbelthiere (Vertebrata). Georg Reimer, Berlin. 660 pp.
Cooper, 1985. A revision of the ornithischian dinosaur Kangnasaurus coetzeei Haughton, with a classification of the Ornithischia. Annals of the South African Museum. 95(8), 281-317.
Thursday, October 14, 2010
"The Princeton Field Guide to Dinosaurs" - The Ornithischians
Finishing up the review series is this post on ornithischians. As with sauropodomorphs, these aren't my speciality, so I don't have educated opinions on most of the issues nor do I always know exactly what the latest consensus is. Honestly, the same kinds of problems are present in this section as the previous one. I think I've figured out Paul's splitter/lumper methodology though. If a taxon is similar to another, but from a different horizon, it's a different species! Doesn't matter if anyone's actually tried to name a distinct taxon from there yet, or if there are actually any differences reported in the literature. If a taxon is from the same horizon as another similar one, they're synonymous! Ignore priority and use the name of the most complete specimen for the taxon. If a species forms a clade with another, they're congeneric! With these three easy steps, you too can lump and split the GSP way. ;)
As with the other sections, there are many excellent reconstructions. My favorites are Scutellosaurus, Gigantspinosaurus, Saichania, Pinacosaurus, Ankylosaurus, Edmontonia, Archaeoceratops, Prenoceratops, Montanaceratops, Talenkauen, Gasparinisaura, Muttaburrasaurus, Probactrosaurus, Tethyshadros, and the many derived hadrosaurs. It's nice to see the ankylosaurs and hadrosaurs reconstructed, since usually people only bother with their skulls.
Like theropods, thyreophorans unjustly suffer from the statement "absence from Antarctica probably reflects lack of sufficient sampling." Despite the fact Antarctopelta is known AND included in the book. Chungkingosaurus and Chialingosaurus are said to probably be juvenile Tuojiangosaurus, but the former is a diagnostic huayangosaurid (Maidment and Wei, 2006) and the latter has priority over Tuojiangosaurus. Upper Tendaguru Kentrosaurus remains "probably belong to a different taxon" while Stegosaurus longispinus "probably is a more basal stegosaurid." These may be true, I don't know. Amusingly, Wuerhosaurus "is not a species of Stegosaurus as has been suggested." I'm not sure why Paul's lumpometer fails here. For "Hesperosaurus (or Stegosaurus) mjosi", "Lack of limbs hinders assessing whether this is a Stegosaurus as some reseachers have concluded." Because Stegosaurus is apomorphy-defined using limb characters?
Dracopelta, Shamosaurus, Gobisaurus, Stegopelta, Niobrarasaurus and Antarctopelta are listed as "polacanthians." Good ol' nonexistent Polacanthia... I'm unaware of these taxa even being referred to Polacanthidae. Pinacosaurus mephistocephalus is listed as a synonym of P. grangeri and Struthiosaurus languedocensis "may be the adult" of S. austriacus. Again, are these plausible? I don't know. But claiming Pawpawsaurus "probably includes Texasetes pleurohalio" is certainly incorrect, as Texasetes has priority. "Euoplocephalus tutus" is placed in quote marks, said to have an inadequate holotype and said to possibly consists of multiple taxa. Horseshoe Canyon specimens are assigned to ""Euoplocephalus" unnamed species?" though, presumably because they're from a different formation.
Butler will be surprised to hear Heterodontosaurus "probably includes the smaller, tuskless Abrictosaurus consors as well as Lycorhinus angustidens."
Homalocephalids are said to probably be immature pachycephalosaurids or females, which leads to "Goyocephale (or Stegoceras) lattimorei" and "Prenocephale (or Stegoceras) prenes" with Homalocephale "probably an immature P. prenes." There's also "Tylocephale (or Stegoceras) gilmorei." Even if he's right about homalocephalids, none of the Asian taxa are especially close to Stegoceras. Of course Paul's Stegoceras is a huge para/polyphyletic mass including every non-Pachycephalosaurus North American taxon at least, since Stegoceras? brevis "may include Colepiocephale lambei", and Stegoceras validum "may include Hansuessia sternbergi." Dracorex and Stygimoloch are probably juvenile Pachycephalosaurus "in which case the spikes are a sexual characteristic, or there may be two species, the other being P. spinifer." But what about the spikes being resorbed?
The only new non-theropod taxonomic name proposed in the book is Paxceratopsia for psittacosaurs and neoceratopsians, but not chaoyangosaurs. Psittacosaurus meileyingensis "probably includes P. ordosensis", Udanoceratops "may include Bainoceratops efremovi" and Gobiceratops "may be a juvenile" Bagaceratops. Again, I'm not sure if these are plausible. I was disappointed to see all non-ceratopsid neoceratopsians called protoceratopsids. Cerasinops is listed twice in the book, with identical entries at least. For ceratopsids, Paul has the odd division between centrosaurines, chasmosaurines AND ceratopsines. Err.... Paul includes only Triceratops and Avaceratops in Ceratopsinae and says "The existence of this group is not certain." Well, since it's never been recovered in an analysis and there's no reason Ceratops itself is close to either genus, I suppose that's true. Paul's ceratopsids are lumped like there's no tomorrow. There's "Albertoceratops (=Diabloceratops) eatoni". All other centrosaurines are Centrosaurus, so we get Centrosaurus (=Styracosaurus) albertensis, C. (=Styracosaurus) ovatus, C. (=Einosaurus[sic]) procurvicornis, C. (=Achelousaurus) horneri, C. (=Pachyrhinosaurus) lakustai, and C. (=Pachyrhinosaurus) canadensis. But Centrosaurus nasicornis and C. apertus are separate, no doubt because they're from different levels of the Dinosaur Park. Not only is such lumping pointless, IF it were true, Monoclonius would be the proper genus since crassus is definitely somewhere in that clade. For chasmosaurines, we get Chasmosaurus (Pentaceratops = Agujaceratops) mariscalensis and Chasmosaurus (Pentaceratops) sternbergi. Which makes both Chasmosaurus and the supposed subgenus Pentaceratops para/polyphyletic. And of course Triceratops is lumped, with Triceratops (=Eotriceratops) xerinsularis, and Nedoceratops (incorrectly listed as Diceratops) a synonym of T. horridus.
Moving on to ornithopods, Hexinlusaurus "is probably immature example of" Agilisaurus louderbacki. Even though the former is closer to ornithopods in Butler's tree. Then we have "Agilisaurus? unnamed species" which was "named Yandusaurus hongheensis based on inadequate remains." Not only is Yandusaurus closer to ornithopods than Agilisaurus, but Yandusaurus has priority over Agilisaurus AND how can you have an unnamed species that used to be a named species?! More predictably bad taxonomy- Othnielosaurus consors was "once Othnielia rex." More like Othnielia isn't necessarily Othnielosaurus. Anabisetia, Gasparinisaura, Talenkauen, Thescelosaurus and Parksosaurus are all listed as hypsilophodonts, but are iguanodonts. Iguanodonts also get the old "absence from Antarctica probably reflects lack of sufficient sampling" treatment, but there's a hadrosaur from there (Case et al., 2000). The Tenontosaurus dossi cranial reconstruction doesn't have premaxillary teeth. For rhabdodont lumping, Rhabdodon (=Zalmoxes) robustus "probably includes Z. shqiperorum." But then for horizon-based splitting, "Dryosaurus unnamed species" (for Utah Middle Morrison remains) is "usually placed in D. altus but probably is a different species than the latter dryosaur, and differing genera cannot be ruled out." The placement of taxa in Paul's iguanodont grades seems problematic, with e.g. Planicoxa being a dryosaur. I was amused that Paul's own taxon Dollodon bampingi is misspelled "bambingi" every time.
Finally, there's the lumptastic hadosaurs. It honestly looks like Paul just used a twenty-year old classification and applied his three lumping/splitting steps. Bactrosaurus "probably includes Gilmoreosaurus mongoliensis." We get Saurolophus (=Lophorthothon[sic]) atopus, Saurolophus (=Prosaurolophus) blackfeetensis, and Saurolophus (=Prosaurolophus) maximus. Lophorhothon isn't even a hadrosaurid, while blackfeetensis is a synonym of maximus, but silly me it's from a different formation. Maisaura (or Brachylophosaurus) peeblesorum "may be a subgenus of Brachylophosaurus", which is just meaningless. There's Kritosaurus (or Gryposaurus) latidens, notabilis, incurvimanus, and monumentensis and Kritosaurus (or Anasazisaurus) horneri. Last I heard, horneri was a synonym of navajovius, incurvimanus was a synonym of notabilis, and you'd need to put Secernosaurus in Kritosaurus if you put Gryposaurus there. Most sadly, we have Aralosaurus (or Kritosaurus) tubiferus, despite the fact Aralosaurus is a lambeosaurine. Pararhabdodon "probably includes Koutalisaurus", which agrees with Prieto-Marquez. Parasaurolophus walkeri and "P. tubicen are not distinctive from one another, and short crested New Mexican P. cyrtocristatus may be a female or subadult of this species." I'm not sure about the evidence for that. Olorotitan "may be the same genus or species as Amurosaurus riabinini", which is untrue as they're not closely related within Lambeosaurinae. We get both Nipponosaurus (or Hypacrosaurus) sachaliensis and Barsboldia (or Hypacrosaurus) sicinskii, though the latter is a saurolophine. In fact, all the helmet-crested lambeosaurines get placed in one genus. There's Hypacrosaurus (=Velafrons) coahuilensis, Hypacrosaurus (=Corythosaurus) casuarius and intermedius, Hypacrosaurus (=Lambeosaurus) clavintialis, lambei and mangicristatus, and Hypacrosaurus? laticaudus. Again, I didn't think clavintialis was valid, while you'd need to put Amurosaurus and Sahaliyania in Hypacrosaurus too if you're lumping like that.
And that's it. Be sure to check out Jaime Headden's review and future commentary too.
As with the other sections, there are many excellent reconstructions. My favorites are Scutellosaurus, Gigantspinosaurus, Saichania, Pinacosaurus, Ankylosaurus, Edmontonia, Archaeoceratops, Prenoceratops, Montanaceratops, Talenkauen, Gasparinisaura, Muttaburrasaurus, Probactrosaurus, Tethyshadros, and the many derived hadrosaurs. It's nice to see the ankylosaurs and hadrosaurs reconstructed, since usually people only bother with their skulls.
Like theropods, thyreophorans unjustly suffer from the statement "absence from Antarctica probably reflects lack of sufficient sampling." Despite the fact Antarctopelta is known AND included in the book. Chungkingosaurus and Chialingosaurus are said to probably be juvenile Tuojiangosaurus, but the former is a diagnostic huayangosaurid (Maidment and Wei, 2006) and the latter has priority over Tuojiangosaurus. Upper Tendaguru Kentrosaurus remains "probably belong to a different taxon" while Stegosaurus longispinus "probably is a more basal stegosaurid." These may be true, I don't know. Amusingly, Wuerhosaurus "is not a species of Stegosaurus as has been suggested." I'm not sure why Paul's lumpometer fails here. For "Hesperosaurus (or Stegosaurus) mjosi", "Lack of limbs hinders assessing whether this is a Stegosaurus as some reseachers have concluded." Because Stegosaurus is apomorphy-defined using limb characters?
Dracopelta, Shamosaurus, Gobisaurus, Stegopelta, Niobrarasaurus and Antarctopelta are listed as "polacanthians." Good ol' nonexistent Polacanthia... I'm unaware of these taxa even being referred to Polacanthidae. Pinacosaurus mephistocephalus is listed as a synonym of P. grangeri and Struthiosaurus languedocensis "may be the adult" of S. austriacus. Again, are these plausible? I don't know. But claiming Pawpawsaurus "probably includes Texasetes pleurohalio" is certainly incorrect, as Texasetes has priority. "Euoplocephalus tutus" is placed in quote marks, said to have an inadequate holotype and said to possibly consists of multiple taxa. Horseshoe Canyon specimens are assigned to ""Euoplocephalus" unnamed species?" though, presumably because they're from a different formation.
Butler will be surprised to hear Heterodontosaurus "probably includes the smaller, tuskless Abrictosaurus consors as well as Lycorhinus angustidens."
Homalocephalids are said to probably be immature pachycephalosaurids or females, which leads to "Goyocephale (or Stegoceras) lattimorei" and "Prenocephale (or Stegoceras) prenes" with Homalocephale "probably an immature P. prenes." There's also "Tylocephale (or Stegoceras) gilmorei." Even if he's right about homalocephalids, none of the Asian taxa are especially close to Stegoceras. Of course Paul's Stegoceras is a huge para/polyphyletic mass including every non-Pachycephalosaurus North American taxon at least, since Stegoceras? brevis "may include Colepiocephale lambei", and Stegoceras validum "may include Hansuessia sternbergi." Dracorex and Stygimoloch are probably juvenile Pachycephalosaurus "in which case the spikes are a sexual characteristic, or there may be two species, the other being P. spinifer." But what about the spikes being resorbed?
The only new non-theropod taxonomic name proposed in the book is Paxceratopsia for psittacosaurs and neoceratopsians, but not chaoyangosaurs. Psittacosaurus meileyingensis "probably includes P. ordosensis", Udanoceratops "may include Bainoceratops efremovi" and Gobiceratops "may be a juvenile" Bagaceratops. Again, I'm not sure if these are plausible. I was disappointed to see all non-ceratopsid neoceratopsians called protoceratopsids. Cerasinops is listed twice in the book, with identical entries at least. For ceratopsids, Paul has the odd division between centrosaurines, chasmosaurines AND ceratopsines. Err.... Paul includes only Triceratops and Avaceratops in Ceratopsinae and says "The existence of this group is not certain." Well, since it's never been recovered in an analysis and there's no reason Ceratops itself is close to either genus, I suppose that's true. Paul's ceratopsids are lumped like there's no tomorrow. There's "Albertoceratops (=Diabloceratops) eatoni". All other centrosaurines are Centrosaurus, so we get Centrosaurus (=Styracosaurus) albertensis, C. (=Styracosaurus) ovatus, C. (=Einosaurus[sic]) procurvicornis, C. (=Achelousaurus) horneri, C. (=Pachyrhinosaurus) lakustai, and C. (=Pachyrhinosaurus) canadensis. But Centrosaurus nasicornis and C. apertus are separate, no doubt because they're from different levels of the Dinosaur Park. Not only is such lumping pointless, IF it were true, Monoclonius would be the proper genus since crassus is definitely somewhere in that clade. For chasmosaurines, we get Chasmosaurus (Pentaceratops = Agujaceratops) mariscalensis and Chasmosaurus (Pentaceratops) sternbergi. Which makes both Chasmosaurus and the supposed subgenus Pentaceratops para/polyphyletic. And of course Triceratops is lumped, with Triceratops (=Eotriceratops) xerinsularis, and Nedoceratops (incorrectly listed as Diceratops) a synonym of T. horridus.
Moving on to ornithopods, Hexinlusaurus "is probably immature example of" Agilisaurus louderbacki. Even though the former is closer to ornithopods in Butler's tree. Then we have "Agilisaurus? unnamed species" which was "named Yandusaurus hongheensis based on inadequate remains." Not only is Yandusaurus closer to ornithopods than Agilisaurus, but Yandusaurus has priority over Agilisaurus AND how can you have an unnamed species that used to be a named species?! More predictably bad taxonomy- Othnielosaurus consors was "once Othnielia rex." More like Othnielia isn't necessarily Othnielosaurus. Anabisetia, Gasparinisaura, Talenkauen, Thescelosaurus and Parksosaurus are all listed as hypsilophodonts, but are iguanodonts. Iguanodonts also get the old "absence from Antarctica probably reflects lack of sufficient sampling" treatment, but there's a hadrosaur from there (Case et al., 2000). The Tenontosaurus dossi cranial reconstruction doesn't have premaxillary teeth. For rhabdodont lumping, Rhabdodon (=Zalmoxes) robustus "probably includes Z. shqiperorum." But then for horizon-based splitting, "Dryosaurus unnamed species" (for Utah Middle Morrison remains) is "usually placed in D. altus but probably is a different species than the latter dryosaur, and differing genera cannot be ruled out." The placement of taxa in Paul's iguanodont grades seems problematic, with e.g. Planicoxa being a dryosaur. I was amused that Paul's own taxon Dollodon bampingi is misspelled "bambingi" every time.
Finally, there's the lumptastic hadosaurs. It honestly looks like Paul just used a twenty-year old classification and applied his three lumping/splitting steps. Bactrosaurus "probably includes Gilmoreosaurus mongoliensis." We get Saurolophus (=Lophorthothon[sic]) atopus, Saurolophus (=Prosaurolophus) blackfeetensis, and Saurolophus (=Prosaurolophus) maximus. Lophorhothon isn't even a hadrosaurid, while blackfeetensis is a synonym of maximus, but silly me it's from a different formation. Maisaura (or Brachylophosaurus) peeblesorum "may be a subgenus of Brachylophosaurus", which is just meaningless. There's Kritosaurus (or Gryposaurus) latidens, notabilis, incurvimanus, and monumentensis and Kritosaurus (or Anasazisaurus) horneri. Last I heard, horneri was a synonym of navajovius, incurvimanus was a synonym of notabilis, and you'd need to put Secernosaurus in Kritosaurus if you put Gryposaurus there. Most sadly, we have Aralosaurus (or Kritosaurus) tubiferus, despite the fact Aralosaurus is a lambeosaurine. Pararhabdodon "probably includes Koutalisaurus", which agrees with Prieto-Marquez. Parasaurolophus walkeri and "P. tubicen are not distinctive from one another, and short crested New Mexican P. cyrtocristatus may be a female or subadult of this species." I'm not sure about the evidence for that. Olorotitan "may be the same genus or species as Amurosaurus riabinini", which is untrue as they're not closely related within Lambeosaurinae. We get both Nipponosaurus (or Hypacrosaurus) sachaliensis and Barsboldia (or Hypacrosaurus) sicinskii, though the latter is a saurolophine. In fact, all the helmet-crested lambeosaurines get placed in one genus. There's Hypacrosaurus (=Velafrons) coahuilensis, Hypacrosaurus (=Corythosaurus) casuarius and intermedius, Hypacrosaurus (=Lambeosaurus) clavintialis, lambei and mangicristatus, and Hypacrosaurus? laticaudus. Again, I didn't think clavintialis was valid, while you'd need to put Amurosaurus and Sahaliyania in Hypacrosaurus too if you're lumping like that.
And that's it. Be sure to check out Jaime Headden's review and future commentary too.
Friday, October 8, 2010
"The Princeton Field Guide to Dinosaurs" - The Sauropodomorphs
Part 3 of the review series, I should preface this by saying that sauropodomorphs aren't my speciality. I don't follow the literature closely, so I don't know if some of Paul's nonstandard ideas have been proposed before, or how likely they are to be correct.
As with the theropods, the reconstructions are plentiful. My favorites include Massospondylus, Lufengosaurus, Yunnanosarus, Jingshanosaurus, Riojasaurus, Gongxianosaurus, Datousaurus, Cetiosaurus and Atlasaurus.
Among non-sauropods, Paul doesn't follow the consensus in a few areas. Ammosaurus is listed separately from Anchisaurus, Ruehleia is said to be an adult Plateosaurus longiceps, Efraasia is back to being a juvenile Plateosaurus gracilis and P. longiceps is kept separate from P. engelhardti. He only does a little lumping, with "Massospondylus (or Plateosaurus = Lufengosaurus) huenei" and "Massospondylus (or Plateosaurus) carinatus". Plateosaurus is usually not in an exclusive clade with Lufengosaurus and Massospondylus, so this seems like an improper synonymy. Even synonymizing Lufengosaurus with Massospondylus seems wrong if Adeopapposaurus and Coloradisaurus are retained in their own genera. In the first of a few examples to be noted here, Paul says Plateosauravus cullingworthi "was Euskelosaurus browni, which is based on inadequate remains." Argh. Euskelosaurus can't become Plateosauravus since the former has priority. According to Yates (2004), Euskelosaurus really is indeterminate and could belong to Plateosauravus or an undescribed prosauropod from the Clocolan District.
Among sauropods, Klamelisaurus is treated as adult Bellusaurus, which I know was suggested, but has anyone actually examined this issue? The mamenchisaurids suffer quite the deconstruction. I agree with Paul that the alpha taxonomy on these things needs to be examined, but since Paul's rationale is never explained and even his intent is sometimes ambiguous, I can't say he sheds much light on the issue. tianfuensis is said not to be Omeisaurus (it is "too different"), while maoianus is placed in the genus with a question mark. hochuanensis and youngi are both said to be in the same genus and perhaps just different sexes of the same species. They're also excluded from Mamenchisaurus based in part on M. constructus having a shorter neck, though I was under the impression M. constructus' cervicals were simply incomplete so restored as being short. Paul also lists (quotation marks his) "Mamenchisaurus" anyuensis, "Mamenchisaurus sinocanadorum" and "Mamenchisaurus jingyanensis." The latter is said to probably belong to one of the other Shangshaximiao species. While the quotation marks would seem to indicate Paul doesn't think anyuensis belongs in Mamenchisaurus, I'm not sure what they imply for sinocanadorum and jingyanensis (both were properly described, so are not nomina nuda).
Among diplodocids, Paul lists "Amphicoelias or Diplodocus altus" and says "Status not certain, may be a distinct genus or Diplodocus." Ack again. Diplodocus altus can never exist, as Amphicoelias has priority over it. There's an unnamed species of Diplodocus listed from Utah represented by "two skulls and majority of a few skeletons." It's illustrated with a complete skeleton and is listed separately from D. longus, D. carnegii, D. hayi and D. halli (wasn't this emmended to hallorum?). Anyone know if the literature supports this? Paul seems to place Apatosaurus parvus, A. excelsus and A. louisae in the subgenus Brontosaurus, which contradicts Upchurch et al.'s (2004) study that found parvus and excelsus to be closer to ajax than to louisae. His statement "Brontosaurus is the shorter, narrower necked version of Apatosaurus from the lower and middle Morrison" wouldn't be agreed on by sauropod experts as far as I know. It's these kinds of statements which make me cringe imagining kids reading the book, since they're just stated as true despite being found nowhere in the literature.
Paul excludes ruyangensis from Huanghetitan and giganteus from Antarctosaurus. Pitekunsaurus is said to be "probably a juvenile of one of the other Anacleto titanosaurs." I have no idea is these things are plausible. While I can never keep track of the metric crapload of titanosaurs being described these days, things like placing Isisaurus outside Lithostrotia but including Huabeisaurus don't seem to mesh with even the pitiful amount of consensus that has been reached regarding their phylogeny. I also don't think the evidence justifies synonymizing Opisthocoelicaudia skarzynskii with Nemegtosaurus mongoliensis or placing Quaesitosaurus in the same genus. It's not like formations with more than one sauropod are uncommon, and I'm doubtful Nemegtosaurus' sister genera have skulls preserved. Finally, Pleurocoelus is said to be "originally Astrodon johnstoni, which was based on inadequate remains." But just like with Euskelosaurus, Astrodon has priority over Pleurocoelus so can never become Pleurocoelus.
Next up, ornithischians *yawn* ;)
As with the theropods, the reconstructions are plentiful. My favorites include Massospondylus, Lufengosaurus, Yunnanosarus, Jingshanosaurus, Riojasaurus, Gongxianosaurus, Datousaurus, Cetiosaurus and Atlasaurus.
Among non-sauropods, Paul doesn't follow the consensus in a few areas. Ammosaurus is listed separately from Anchisaurus, Ruehleia is said to be an adult Plateosaurus longiceps, Efraasia is back to being a juvenile Plateosaurus gracilis and P. longiceps is kept separate from P. engelhardti. He only does a little lumping, with "Massospondylus (or Plateosaurus = Lufengosaurus) huenei" and "Massospondylus (or Plateosaurus) carinatus". Plateosaurus is usually not in an exclusive clade with Lufengosaurus and Massospondylus, so this seems like an improper synonymy. Even synonymizing Lufengosaurus with Massospondylus seems wrong if Adeopapposaurus and Coloradisaurus are retained in their own genera. In the first of a few examples to be noted here, Paul says Plateosauravus cullingworthi "was Euskelosaurus browni, which is based on inadequate remains." Argh. Euskelosaurus can't become Plateosauravus since the former has priority. According to Yates (2004), Euskelosaurus really is indeterminate and could belong to Plateosauravus or an undescribed prosauropod from the Clocolan District.
Among sauropods, Klamelisaurus is treated as adult Bellusaurus, which I know was suggested, but has anyone actually examined this issue? The mamenchisaurids suffer quite the deconstruction. I agree with Paul that the alpha taxonomy on these things needs to be examined, but since Paul's rationale is never explained and even his intent is sometimes ambiguous, I can't say he sheds much light on the issue. tianfuensis is said not to be Omeisaurus (it is "too different"), while maoianus is placed in the genus with a question mark. hochuanensis and youngi are both said to be in the same genus and perhaps just different sexes of the same species. They're also excluded from Mamenchisaurus based in part on M. constructus having a shorter neck, though I was under the impression M. constructus' cervicals were simply incomplete so restored as being short. Paul also lists (quotation marks his) "Mamenchisaurus" anyuensis, "Mamenchisaurus sinocanadorum" and "Mamenchisaurus jingyanensis." The latter is said to probably belong to one of the other Shangshaximiao species. While the quotation marks would seem to indicate Paul doesn't think anyuensis belongs in Mamenchisaurus, I'm not sure what they imply for sinocanadorum and jingyanensis (both were properly described, so are not nomina nuda).
Among diplodocids, Paul lists "Amphicoelias or Diplodocus altus" and says "Status not certain, may be a distinct genus or Diplodocus." Ack again. Diplodocus altus can never exist, as Amphicoelias has priority over it. There's an unnamed species of Diplodocus listed from Utah represented by "two skulls and majority of a few skeletons." It's illustrated with a complete skeleton and is listed separately from D. longus, D. carnegii, D. hayi and D. halli (wasn't this emmended to hallorum?). Anyone know if the literature supports this? Paul seems to place Apatosaurus parvus, A. excelsus and A. louisae in the subgenus Brontosaurus, which contradicts Upchurch et al.'s (2004) study that found parvus and excelsus to be closer to ajax than to louisae. His statement "Brontosaurus is the shorter, narrower necked version of Apatosaurus from the lower and middle Morrison" wouldn't be agreed on by sauropod experts as far as I know. It's these kinds of statements which make me cringe imagining kids reading the book, since they're just stated as true despite being found nowhere in the literature.
Paul excludes ruyangensis from Huanghetitan and giganteus from Antarctosaurus. Pitekunsaurus is said to be "probably a juvenile of one of the other Anacleto titanosaurs." I have no idea is these things are plausible. While I can never keep track of the metric crapload of titanosaurs being described these days, things like placing Isisaurus outside Lithostrotia but including Huabeisaurus don't seem to mesh with even the pitiful amount of consensus that has been reached regarding their phylogeny. I also don't think the evidence justifies synonymizing Opisthocoelicaudia skarzynskii with Nemegtosaurus mongoliensis or placing Quaesitosaurus in the same genus. It's not like formations with more than one sauropod are uncommon, and I'm doubtful Nemegtosaurus' sister genera have skulls preserved. Finally, Pleurocoelus is said to be "originally Astrodon johnstoni, which was based on inadequate remains." But just like with Euskelosaurus, Astrodon has priority over Pleurocoelus so can never become Pleurocoelus.
Next up, ornithischians *yawn* ;)
Thursday, October 7, 2010
"The Princeton Field Guide to Dinosaurs - The Theropods
Having reviewed Paul's new book in the last post, this one will examine the good, bad and just plain interesting things it has to say about theropods. It's organized in the order Paul discusses the taxa.
The seemingly rigorous Staurikosaurus skeletal includes anterior cervicals, chevrons, the whole pectoral girdle, a humerus and pes.
The coelophysoids have meager descriptions as with most taxa, but most every skulless one (Procompsognathus, Podokesaurus, Gojirasaurus, Liliensternus, Segisaurus, but not Lophostropheus) contains the phrase "not known whether head crests were present." This is repetitive (it would be simpler to say only Megapnosaurus and Coelophysis are known to LACK crests) and you would think there's more useful information the space could be spent on, like Gojirasaurus being a chimaera, Procompsognathus being perhaps nondinosaurian and with a controversial skull, Segisaurus being thought to have solid bones and unfused clavicles until recently, etc..
Among abelisaurs, the Rahiolisaurus skeleton is labeled Indosuchus and seems to just be reposed from Chatterjee and Rudra's schematic drawing (which is now known to be wrong in various ways thanks to the description). A complete skull is illustrated and listed for Rajasaurus, but while there is a cast that's often photographed, only a braincase is present according to the description. For those curious why Aucasaurus is sunk into Abelisaurus- "the only reason this does not appear to be a juvenile A. comahuensis is that fusion of skeletal elements suggests it is an adult." It should be noted Paul has an odd phylogeny where ceratosaurids and elaphrosaurs are closer to tetanurines than abelisauroids are. The seemingly rigorous Elaphrosaurus skeletal incorrectly has a complete vertebral column, all chevrons (only one is preserved) and complete pes, but doesn't include the scapulocoracoid or metacarpals.
Poekilopleuron bucklandii being the same genus and/or species as Megalosaurus bucklandii might have been a viable idea back in 1988, but not now that both have been redescribed. Another odd aspect to Paul's phylogeny is that Piatnitzkysaurus, Condorraptor, Magnosaurus, Eustreptospondylus (as Streptospondylus) and Afrovenator are avetheropods. The rationale for sinking Eustreptospondylus- "Eustreptospondylus oxoniensis is tentatively placed in Streptospondylus altdorfensis." Eustreptospondylus' skeletal is odd in lacking most of the skull besides the premaxilla, maxilla and quadrate, but a lot of what is shown is not preserved (ribs, most caudal vertebrae, chevrons, etc.).
Sinraptor hepingensis is synonymized with Yangchuanosaurus shangyouensis, but S. dongi (with a humerus and coracoid in its rigorous skeletal) is kept separate. Monolophosaurus and Guanlong are both sinraptorids, which has never been supported to my knowledge. Paul retains the old short snout vs. long snout Allosaurus dichotomy which Chure has showed is untrue. For Neovenator, he states "That researchers have disagreed whether this is a basal tyrannosauroid or an allosauroid suggests these groups may be more closely related than thought." But whoever proposed Neovenator is a tyrannosauroid?
For Coelurosauria, Paul states "The validity of the group is not certain." But who has ever had a theropod phylogeny without it? While I do applaud Paul's indicating when taxa are based on juvenile specimens, he's incorrect in calling the heavily fused Bagaraatan type a juvenile and the young Raptorex type an adult. On the other hand, I was happy to see him call both Alioramus species juveniles and probably synonymous. One new combination missing in my taxonomy post is "Appalachiosaurus (or Albertosaurus) montgomeriensis." Using Carr's data, that seems fine as long as Bistahieversor is Albertosaurus too.
Paul lumps all American ornithomimids into Struthiomimus, but says Struthiomimus? sedens "includes Ornithomimus velox, which is based on entirely inadequate remains." GAK!!! Impossible. Ornithomimus and the species velox have priority over Struthiomimus and sedens. If Ornithomimus' syntypes are entirely inadequate (and they're not), it couldn't be assigned to the same species as sedens.
The rigorous Ornitholestes skeletal lacks any forearm or manus material (even though the famous manus has been reassigned to Tanycolagreus, the holotype has manus material as well). Scansoriopteryx is used instead of Epidendrosaurus, which is nice. Yet the taxon is not placed with Epidexipteryx, as the latter is assigned to Oviraptorosauria instead. Wherever the taxa belong, their morphology is so similar that they may even be synonymous. If Paul would have used all the manual phalanges in Epidexipteryx, he would have found it impossible to restore with normal hands.
Shanag is sunk into Sinornithosaurus because "Too little is known to distinguish this from Sinornithosaurus." Tsaagan and Graciliraptor don't even get that much explanation. Deinonychus' skeletal is oddly incomplete (no scapula, humerus, ilium, pubis, femur, tibia or fibula), which I'm assuming is due to Paul's statement Lower Cloverly remains "are probably one or more different taxa."
The oviraptorosaurs are all given bifurcated tail fans, but Gatesy (2001) showed this was an illusion in Caudipteryx. Both Epidexipteryx and omnivoropterygids are placed in Oviraptorosauria, which has never been supported by an analysis, but I do like that Paul uses Omnivoropterygidae instead of Sapeornithidae. The caenagnathid taxonomy is highly confused. Using Paul's names, it consists of- Caenagnathus collinsi (only the type mandible), Caenagnathus? sp. (the two undescribed Triebold skeletons), Chirostenotes pergracilis (said to possibly include elegans), Chirostenotes? sp. (the specimen described in Sues, 1997), and Elmisaurus (or Chirostenotes) rarus. Where to begin? The Triebold skeletons combine Caenagnathus jaws with Chirostenotes postcrania, so there's no reason to keep the genera separate, let alone refer the Triebold material to one genus or the other. elegans is more similar to Elmisaurus despite the undefended assertions of some recent papers (Sues, 1997; Maryanska et al., 2002; Osmolska et al., 2004). The Horseshoe Canyon specimen described by Sues has never been suggested to belong to a distinct taxon in the literature, and was seemingly just separated based on stratigraphy. Shanyangosaurus is listed as a caenagnathid, which I find amusing since I suggested it was an oviraptorosaur back in 2000, that was also followed by Holtz et al. (2004). Ironically, I no longer think my analysis was sufficient to place it anywhere specific within Maniraptora.
Oviraptorids themselves were lumped a lot. For Citipati osmolskae, Paul says "It is probable that crestless Khaan mckennai is the juvenile form of this species." And for "Conchoraptor (or Citipati) gracilis", he says "It is probable that all specimens from this formation are juveniles and adults of one species whose taxonomy is complicated because the genus portion of the original name Ingenia yanshini turned out to be preoccupied by an invertebrate." But as I noted before, just because Ingenia is preoccupied doesn't mean yanshini wouldn't still be the species name. Nor can Conchoraptor gracilis ever be Citipati gracilis, since Conchoraptor has priority over Citipati. His illustration for this conglomerate of taxa is basically "Ingenia" but with that privately owned skull with the very tall pointed crest. I do like that Paul illustrates the internal nostrils on the side of the ventrally projected palate in oviraptorids.
The reconstruction of Beipiaosaurus uses the new anterior skeleton and features a silly-looking vaguely stegosaur-like skull with a pointy snout. Contra to Paul who thinks Nothronychus graffami (mistyped grafmani) might be synonymous with N. mckinleyi, I'm doubtful they're even congeneric.
Next up, sauropodomorphs...
The seemingly rigorous Staurikosaurus skeletal includes anterior cervicals, chevrons, the whole pectoral girdle, a humerus and pes.
The coelophysoids have meager descriptions as with most taxa, but most every skulless one (Procompsognathus, Podokesaurus, Gojirasaurus, Liliensternus, Segisaurus, but not Lophostropheus) contains the phrase "not known whether head crests were present." This is repetitive (it would be simpler to say only Megapnosaurus and Coelophysis are known to LACK crests) and you would think there's more useful information the space could be spent on, like Gojirasaurus being a chimaera, Procompsognathus being perhaps nondinosaurian and with a controversial skull, Segisaurus being thought to have solid bones and unfused clavicles until recently, etc..
Among abelisaurs, the Rahiolisaurus skeleton is labeled Indosuchus and seems to just be reposed from Chatterjee and Rudra's schematic drawing (which is now known to be wrong in various ways thanks to the description). A complete skull is illustrated and listed for Rajasaurus, but while there is a cast that's often photographed, only a braincase is present according to the description. For those curious why Aucasaurus is sunk into Abelisaurus- "the only reason this does not appear to be a juvenile A. comahuensis is that fusion of skeletal elements suggests it is an adult." It should be noted Paul has an odd phylogeny where ceratosaurids and elaphrosaurs are closer to tetanurines than abelisauroids are. The seemingly rigorous Elaphrosaurus skeletal incorrectly has a complete vertebral column, all chevrons (only one is preserved) and complete pes, but doesn't include the scapulocoracoid or metacarpals.
Poekilopleuron bucklandii being the same genus and/or species as Megalosaurus bucklandii might have been a viable idea back in 1988, but not now that both have been redescribed. Another odd aspect to Paul's phylogeny is that Piatnitzkysaurus, Condorraptor, Magnosaurus, Eustreptospondylus (as Streptospondylus) and Afrovenator are avetheropods. The rationale for sinking Eustreptospondylus- "Eustreptospondylus oxoniensis is tentatively placed in Streptospondylus altdorfensis." Eustreptospondylus' skeletal is odd in lacking most of the skull besides the premaxilla, maxilla and quadrate, but a lot of what is shown is not preserved (ribs, most caudal vertebrae, chevrons, etc.).
Sinraptor hepingensis is synonymized with Yangchuanosaurus shangyouensis, but S. dongi (with a humerus and coracoid in its rigorous skeletal) is kept separate. Monolophosaurus and Guanlong are both sinraptorids, which has never been supported to my knowledge. Paul retains the old short snout vs. long snout Allosaurus dichotomy which Chure has showed is untrue. For Neovenator, he states "That researchers have disagreed whether this is a basal tyrannosauroid or an allosauroid suggests these groups may be more closely related than thought." But whoever proposed Neovenator is a tyrannosauroid?
For Coelurosauria, Paul states "The validity of the group is not certain." But who has ever had a theropod phylogeny without it? While I do applaud Paul's indicating when taxa are based on juvenile specimens, he's incorrect in calling the heavily fused Bagaraatan type a juvenile and the young Raptorex type an adult. On the other hand, I was happy to see him call both Alioramus species juveniles and probably synonymous. One new combination missing in my taxonomy post is "Appalachiosaurus (or Albertosaurus) montgomeriensis." Using Carr's data, that seems fine as long as Bistahieversor is Albertosaurus too.
Paul lumps all American ornithomimids into Struthiomimus, but says Struthiomimus? sedens "includes Ornithomimus velox, which is based on entirely inadequate remains." GAK!!! Impossible. Ornithomimus and the species velox have priority over Struthiomimus and sedens. If Ornithomimus' syntypes are entirely inadequate (and they're not), it couldn't be assigned to the same species as sedens.
The rigorous Ornitholestes skeletal lacks any forearm or manus material (even though the famous manus has been reassigned to Tanycolagreus, the holotype has manus material as well). Scansoriopteryx is used instead of Epidendrosaurus, which is nice. Yet the taxon is not placed with Epidexipteryx, as the latter is assigned to Oviraptorosauria instead. Wherever the taxa belong, their morphology is so similar that they may even be synonymous. If Paul would have used all the manual phalanges in Epidexipteryx, he would have found it impossible to restore with normal hands.
Shanag is sunk into Sinornithosaurus because "Too little is known to distinguish this from Sinornithosaurus." Tsaagan and Graciliraptor don't even get that much explanation. Deinonychus' skeletal is oddly incomplete (no scapula, humerus, ilium, pubis, femur, tibia or fibula), which I'm assuming is due to Paul's statement Lower Cloverly remains "are probably one or more different taxa."
The oviraptorosaurs are all given bifurcated tail fans, but Gatesy (2001) showed this was an illusion in Caudipteryx. Both Epidexipteryx and omnivoropterygids are placed in Oviraptorosauria, which has never been supported by an analysis, but I do like that Paul uses Omnivoropterygidae instead of Sapeornithidae. The caenagnathid taxonomy is highly confused. Using Paul's names, it consists of- Caenagnathus collinsi (only the type mandible), Caenagnathus? sp. (the two undescribed Triebold skeletons), Chirostenotes pergracilis (said to possibly include elegans), Chirostenotes? sp. (the specimen described in Sues, 1997), and Elmisaurus (or Chirostenotes) rarus. Where to begin? The Triebold skeletons combine Caenagnathus jaws with Chirostenotes postcrania, so there's no reason to keep the genera separate, let alone refer the Triebold material to one genus or the other. elegans is more similar to Elmisaurus despite the undefended assertions of some recent papers (Sues, 1997; Maryanska et al., 2002; Osmolska et al., 2004). The Horseshoe Canyon specimen described by Sues has never been suggested to belong to a distinct taxon in the literature, and was seemingly just separated based on stratigraphy. Shanyangosaurus is listed as a caenagnathid, which I find amusing since I suggested it was an oviraptorosaur back in 2000, that was also followed by Holtz et al. (2004). Ironically, I no longer think my analysis was sufficient to place it anywhere specific within Maniraptora.
Oviraptorids themselves were lumped a lot. For Citipati osmolskae, Paul says "It is probable that crestless Khaan mckennai is the juvenile form of this species." And for "Conchoraptor (or Citipati) gracilis", he says "It is probable that all specimens from this formation are juveniles and adults of one species whose taxonomy is complicated because the genus portion of the original name Ingenia yanshini turned out to be preoccupied by an invertebrate." But as I noted before, just because Ingenia is preoccupied doesn't mean yanshini wouldn't still be the species name. Nor can Conchoraptor gracilis ever be Citipati gracilis, since Conchoraptor has priority over Citipati. His illustration for this conglomerate of taxa is basically "Ingenia" but with that privately owned skull with the very tall pointed crest. I do like that Paul illustrates the internal nostrils on the side of the ventrally projected palate in oviraptorids.
The reconstruction of Beipiaosaurus uses the new anterior skeleton and features a silly-looking vaguely stegosaur-like skull with a pointy snout. Contra to Paul who thinks Nothronychus graffami (mistyped grafmani) might be synonymous with N. mckinleyi, I'm doubtful they're even congeneric.
Next up, sauropodomorphs...
Wednesday, October 6, 2010
"The Princeton Field Guide to Dinosaurs" - The Review
One of the perks to working at a bookstore is being able to borrow books, and today I checked out Gregory S. Paul's newest work. My comments before have been based only on the snippets available on Google Books, which isn't exactly fair. I'm only going to concentrate on the theropod section for examples, since that's what I'm most familiar with.
When people think 'Gregory S. Paul', they think excellent skeletals and restorations, and this book's overflowing with them. My theropod favorites include Limusaurus, Acrocanthosaurus, Sinornithomimus, NGMC 2124, Sinocalliopteryx, Buitreraptor, Jinfengopteryx, Mei, the Two Medicine Troodon, Sapeornis and Protarchaeopteryx. One thing I like is how many are rigorous in showing only the known material. The unfortunate counterpoint is that that leaves one thinking the reconstructions which are complete indicate complete skeletons are known, but this is often not the case. I also liked the PDW way of illustrating skulls better, with thinner lines and texturing. The life restorations are spectacular as always. I love the Dromiceiomimus scraping eggs and the Sinosauropteryx leaping for a Confuciusornis as two modern updates to classic themes.
The other thing people think of when they hear 'Gregory S. Paul' is taxonomic lumping. ;) As I described in this post, he lumps a LOT of taxa together. I think this will be confusing to most readers, who won't realize a lot of these new combinations aren't found in the literature. While sometimes Paul notes what he changes in the taxonomy, he almost never states when something is his unique idea, or followed by other researchers. Interestingly on page 42 he states "The phylogeny and taxonomy offered here are not a formal proposal." This would seem to qualify for ICZN Article 8.2- A work that contains a statement to the effect that it is not issued for public and permanent scientific record, or for purposes of zoological nomenclature, is not published within the meaning of the Code. So perhaps Paul's new combinations are all nomina nuda.
Interestingly, Paul may lump genera and many species, but he also features a wide range of unnamed species. These include Padian's (1986) Coelophysis, the supposed Morrison Elaphrosaurus, Portuguese Ceratosaurus, problematic long-snouted Allosaurus, Dinosaur Park and Two Medicine Daspletosaurus, Dinosaur Park Struthiomimus, NGMC 2124, and Triebold and Horseshoe Canyon caenagnathids. While some of these have been proposed in the literature, others haven't and seem to be largely stratigraphy-based. I think the space would have been better spent including additional named taxa, such as Halticosaurus, Genyodectes, Betasuchus, Velocisaurus, Chuandongocoelurus, Erectopus, Metriacanthosaurus, Becklespinax, Archaeornithoides, Variraptor, Borogovia, etc..
The first 63 pages consist of standard introductory material- anatomy, behavior, trackways, history, extinction, etc.. It's largely what one finds in many dinosaur books, but is more accurate than any others I can recall. One unique section is "Dinosaur Safari", which playfully imagines how human time travelers might deal with the Mesozoic. I do think the book could have benefited from an additional editor besides Kirkland, as there are occasional typos (the Landian stage of the Middle Triassic, Pycnoneosaurus, Ricardoesteria, protoarchaeopterygids, etc.). Also the accuracy of the temporal distribution of different groups on the timescale of pages 64-65 is subpar, with most maniraptoriform clades appearing too late for instance.
The main portion of the book is of course the taxonomic section. I stand by my previous complaint that this is not effective as a field guide, since nearly all the taxa lack any useful description or indication of diagnostic features. It's more like Sattler's 1983 "The Illustrated Dinosaur Dictionary" or Lambert's 1990 "The Dinosaur Data Book", with less information on each taxon than the former, but much more than the latter. It's also more technical than either in including species, stages, formations and more anatomical terms. Yet it's also less complete than either, and while obviously you can't reconstruct Ornithodesmus or Bradycneme, I don't think I'm alone among dinosaur enthusiasts in wanting my books to include every taxon.
The descriptions that do exist are often so vague as to be pointless. For instance, coelurosaurs are described as follows- "Highly variable. Tail long to very short. Arm from longer than leg to severely reduced. Leg extremely gracile to robust, toes four to three." Well... I guess some amphiumas and sloths are excluded at least. ;) That doesn't tell you anything about what distinguishes the group. The individual species descriptions suffer the same problem, when they mention any features at all. And a disturbingly large number of taxa are merely said to be standard for their group, including rather distinctive ones such as Herrerasaurus, Segisaurus, Noasaurus, Torvosaurus, Piatnitzkysaurus, Eustreptospondylus, Gasosaurus, Siamotyannus, sinraptorids, Carcharodontosaurus, Giganotosaurus, Mapusaurus, Mononykus, Mahakala, Sinornithoides, Nanshiungosaurus and Erliansaurus. Others are said to have insufficient information, but it's inconsistantly applied. While Duriavenator and Ilokelesia get a description, Elaphrosaurus, Elmisaurus and Neimongosaurus don't.
The theropod groups (Theropoda, Tetanurae, Coelurosauria, Maniraptora, etc.) are never implied to include pygostylians in the introductory sections, so reading that e.g. maniraptorans only lasted to "the end of the dinosaur era" is rather odd. All major theropod taxa have the following in their notes- "absence from Antarctica probably reflects lack of sufficient sampling." Not only is it repetitive, it's unecessary since we have both Molnar et al.'s (1996) basal tetanurine tibia and Case et al.'s (2007) supposed dromaeosaur from the continent. The habits section gets particularily speculative. For instance, herrerasaurs are said to be pursuit predators. Really? Of the included taxa, Alwalkeria and Chindesaurus are far too poorly known, Eoraptor seems omnivorous and Herrerasaurus is massively built with shorter tibiae than femora. I suppose Staurikosaurus may have been, but the topic has never been studied to my knowledge. One excellent practice is taxa known only from young specimens aren't given a size and are instead marked "Adult size not certain."
"The Princeton Field Guide to Dinosaurs" is thus extremely accurate in general and full of amazing artwork, but isn't very useful for learning about individual dinosaur species or groups. It also contains a lot of information which is not based on the literature and often contradicts the consensus, which most readers won't know. I'd recommend it for young readers who aren't ready for Glut's encyclopedias or The Dinosauria yet.
Next up, theropod criticism and commentary.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
When people think 'Gregory S. Paul', they think excellent skeletals and restorations, and this book's overflowing with them. My theropod favorites include Limusaurus, Acrocanthosaurus, Sinornithomimus, NGMC 2124, Sinocalliopteryx, Buitreraptor, Jinfengopteryx, Mei, the Two Medicine Troodon, Sapeornis and Protarchaeopteryx. One thing I like is how many are rigorous in showing only the known material. The unfortunate counterpoint is that that leaves one thinking the reconstructions which are complete indicate complete skeletons are known, but this is often not the case. I also liked the PDW way of illustrating skulls better, with thinner lines and texturing. The life restorations are spectacular as always. I love the Dromiceiomimus scraping eggs and the Sinosauropteryx leaping for a Confuciusornis as two modern updates to classic themes.
The other thing people think of when they hear 'Gregory S. Paul' is taxonomic lumping. ;) As I described in this post, he lumps a LOT of taxa together. I think this will be confusing to most readers, who won't realize a lot of these new combinations aren't found in the literature. While sometimes Paul notes what he changes in the taxonomy, he almost never states when something is his unique idea, or followed by other researchers. Interestingly on page 42 he states "The phylogeny and taxonomy offered here are not a formal proposal." This would seem to qualify for ICZN Article 8.2- A work that contains a statement to the effect that it is not issued for public and permanent scientific record, or for purposes of zoological nomenclature, is not published within the meaning of the Code. So perhaps Paul's new combinations are all nomina nuda.
Interestingly, Paul may lump genera and many species, but he also features a wide range of unnamed species. These include Padian's (1986) Coelophysis, the supposed Morrison Elaphrosaurus, Portuguese Ceratosaurus, problematic long-snouted Allosaurus, Dinosaur Park and Two Medicine Daspletosaurus, Dinosaur Park Struthiomimus, NGMC 2124, and Triebold and Horseshoe Canyon caenagnathids. While some of these have been proposed in the literature, others haven't and seem to be largely stratigraphy-based. I think the space would have been better spent including additional named taxa, such as Halticosaurus, Genyodectes, Betasuchus, Velocisaurus, Chuandongocoelurus, Erectopus, Metriacanthosaurus, Becklespinax, Archaeornithoides, Variraptor, Borogovia, etc..
The first 63 pages consist of standard introductory material- anatomy, behavior, trackways, history, extinction, etc.. It's largely what one finds in many dinosaur books, but is more accurate than any others I can recall. One unique section is "Dinosaur Safari", which playfully imagines how human time travelers might deal with the Mesozoic. I do think the book could have benefited from an additional editor besides Kirkland, as there are occasional typos (the Landian stage of the Middle Triassic, Pycnoneosaurus, Ricardoesteria, protoarchaeopterygids, etc.). Also the accuracy of the temporal distribution of different groups on the timescale of pages 64-65 is subpar, with most maniraptoriform clades appearing too late for instance.
The main portion of the book is of course the taxonomic section. I stand by my previous complaint that this is not effective as a field guide, since nearly all the taxa lack any useful description or indication of diagnostic features. It's more like Sattler's 1983 "The Illustrated Dinosaur Dictionary" or Lambert's 1990 "The Dinosaur Data Book", with less information on each taxon than the former, but much more than the latter. It's also more technical than either in including species, stages, formations and more anatomical terms. Yet it's also less complete than either, and while obviously you can't reconstruct Ornithodesmus or Bradycneme, I don't think I'm alone among dinosaur enthusiasts in wanting my books to include every taxon.
The descriptions that do exist are often so vague as to be pointless. For instance, coelurosaurs are described as follows- "Highly variable. Tail long to very short. Arm from longer than leg to severely reduced. Leg extremely gracile to robust, toes four to three." Well... I guess some amphiumas and sloths are excluded at least. ;) That doesn't tell you anything about what distinguishes the group. The individual species descriptions suffer the same problem, when they mention any features at all. And a disturbingly large number of taxa are merely said to be standard for their group, including rather distinctive ones such as Herrerasaurus, Segisaurus, Noasaurus, Torvosaurus, Piatnitzkysaurus, Eustreptospondylus, Gasosaurus, Siamotyannus, sinraptorids, Carcharodontosaurus, Giganotosaurus, Mapusaurus, Mononykus, Mahakala, Sinornithoides, Nanshiungosaurus and Erliansaurus. Others are said to have insufficient information, but it's inconsistantly applied. While Duriavenator and Ilokelesia get a description, Elaphrosaurus, Elmisaurus and Neimongosaurus don't.
The theropod groups (Theropoda, Tetanurae, Coelurosauria, Maniraptora, etc.) are never implied to include pygostylians in the introductory sections, so reading that e.g. maniraptorans only lasted to "the end of the dinosaur era" is rather odd. All major theropod taxa have the following in their notes- "absence from Antarctica probably reflects lack of sufficient sampling." Not only is it repetitive, it's unecessary since we have both Molnar et al.'s (1996) basal tetanurine tibia and Case et al.'s (2007) supposed dromaeosaur from the continent. The habits section gets particularily speculative. For instance, herrerasaurs are said to be pursuit predators. Really? Of the included taxa, Alwalkeria and Chindesaurus are far too poorly known, Eoraptor seems omnivorous and Herrerasaurus is massively built with shorter tibiae than femora. I suppose Staurikosaurus may have been, but the topic has never been studied to my knowledge. One excellent practice is taxa known only from young specimens aren't given a size and are instead marked "Adult size not certain."
"The Princeton Field Guide to Dinosaurs" is thus extremely accurate in general and full of amazing artwork, but isn't very useful for learning about individual dinosaur species or groups. It also contains a lot of information which is not based on the literature and often contradicts the consensus, which most readers won't know. I'd recommend it for young readers who aren't ready for Glut's encyclopedias or The Dinosauria yet.
Next up, theropod criticism and commentary.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
Tuesday, October 5, 2010
But this C. longicollis syntype isn't Cloelophysis
Again, something I noticed while cataloging past Coelophysis diagnoses. Back in 1887, Cope noted that what would be named Coelophysis (Coelurus longicollis and bauri at the time) differs from Anchisaurus (his Megadactylus) and Megalosaurus in lacking an ectocondylar tuber on the femur. This is also mentioned as a diagnostic character in his 1889 note naming Coelophysis. This caught my eye since I had just dealt with ectocondylar tubers for Kayentavenator. So I checked Huene's (1906, 1915) papers describing and illustrating the original Coelophysis material, and indeed the complete syntype femur of C. longicollis (AMNH 2704) lacks an ectocondylar tuber. This is unlike theropods (or shuvosaurids, which C. bauri syntype femur AMNH 2725 was referred to by Nesbitt et al., 2007), but is similar to silesaurids like Silesaurus and Eucoelophysis. Also like silesaurids but unlike theropods, the femoral head is parallelogram-shaped instead of distinctly offset. Rather unsurprisingly, it seems to have autapomorphies of the contemporaneous Eucoelophysis (after Ezcurra, 2006)- no trochanteric shelf, reduced fourth trochanter.
This underscores the fact Cope's original Coelophysis material can't be assumed to be a single taxon. We now have Coelophysis bauri (cervical AMNH 2701), Eucoelophysis baldwini (femur AMNH 2704), Shuvosauridae (femur AMNH 2725), Dromomeron romeri (femur AMNH 2721- Nesbitt et al., 2009) and Parasuchia (teeth AMNH 2733- Padian, 1986). Yet it also shows that some of the material IS diagnostic, people just have to bother actually examining it.
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| Femora in lateral and anterior view of (left to right) Silesaurus (after Dzik, 2003), Eucoelophysis (after Ezcurra, 2006), Coelophysis longicollis syntype AMNH 2704 (after Huene, 1915), and Coelophysis bauri with proximal lateral view of kayentakatae (after Spielmann et al., 2007 and Rowe, 1989 respectively). |
This underscores the fact Cope's original Coelophysis material can't be assumed to be a single taxon. We now have Coelophysis bauri (cervical AMNH 2701), Eucoelophysis baldwini (femur AMNH 2704), Shuvosauridae (femur AMNH 2725), Dromomeron romeri (femur AMNH 2721- Nesbitt et al., 2009) and Parasuchia (teeth AMNH 2733- Padian, 1986). Yet it also shows that some of the material IS diagnostic, people just have to bother actually examining it.
That supposedly indeterminate Coelophysis type material
The Kayentavenator study encouraged me to clean up and flesh out the coelophysoid portion of my website. In doing so, I found something interesting.
By now, everyone knows the history of Coelophysis. Cope based the genus on a collection of disarticulated elements found in 1881, but in 1947 the famous Ghost Ranch* bonebed of hundreds of specimens was found, which Colbert referred to Coelophysis. Since then, the Ghost Ranch specimens have formed the basis for our understanding of Coelophysis bauri. Hunt and Lucas (1991) stated Cope's material is indeterminate and created the new taxon Rioarribasaurus colberti for the Ghost Ranch taxon. Colbert et al. (1992) petitioned the ICZN to make a Ghost Ranch specimen the neotype of Coelophysis, which was accepted by the ICZN in 1996.
* Why is this now being called the Whitaker quarry, by the way? It seems pointless to rename such a well known locality.
Now Cope's Coelophysis material was referred to three species, C. longicollis, C. bauri and C. willistoni. Hay (1930) designated bauri as the type species without comment. After a flawed attempt by Welles (1984), Colbert (1989 for C. bauri) and Hunt and Lucas (1991 for C. longicollis and C. willistoni) were the first to actually designate lectotype specimens from Cope's syntypes. C. longicollis' lectotype is the cervical vertebra AMNH 2701. Hunt and Lucas state-
"The lectotype of C. longicollis is not diagnostic beyond the level of a primitive theropod, and we consider the taxon a nomen dubium. In so concluding, we emphasize that whichever of COPE'S syntypes of C. longicollis is chosen, it a nomen dubium, because none of the syntypes are diagnostic."
Just as with most declared nomina dubia, a brief statement without any comparison is deemed sufficient to make a taxon indeterminate. Yet anyone who saw AMNH 2701 could note it's certainly not just a primitive theropod. If nothing else, its elongation is only seen in derived coelophysoids. Beyond that though, today I noticed it has anterior pedicular foramina. These are so far only known in Coelophysis bauri, and are absent in "Megapnosaurus" kayentakatae and the Shake-n-Bake coelophysid for instance. Tykoski (2005) considered them autapomorphic for C. bauri, though he noted the condition in Megapnosaurus is unknown due to the brief description.
Interestingly, C. longicollis was based on more specimens than C. bauri, which were more complete than those of the latter species, was larger, and was described first in Cope's paper. It could have easily ended up being the type species of Coelophysis if not for Hay's seemingly arbitrary decision. And in that case, the type of Coelophysis would have been diagnostic after all, making the neotype designation unecessary. As it is, Coelophysis and its type species bauri are both based on a complete Ghost Ranch skeleton now, so it doesn't even matter if the bauri lectotype (an incomplete sacrum and ilial fragment) are diagnostic. But longicollis can now be made a synonym of bauri at least with evidence besides the assumption all of Cope's material belonged to one taxon.
By now, everyone knows the history of Coelophysis. Cope based the genus on a collection of disarticulated elements found in 1881, but in 1947 the famous Ghost Ranch* bonebed of hundreds of specimens was found, which Colbert referred to Coelophysis. Since then, the Ghost Ranch specimens have formed the basis for our understanding of Coelophysis bauri. Hunt and Lucas (1991) stated Cope's material is indeterminate and created the new taxon Rioarribasaurus colberti for the Ghost Ranch taxon. Colbert et al. (1992) petitioned the ICZN to make a Ghost Ranch specimen the neotype of Coelophysis, which was accepted by the ICZN in 1996.
* Why is this now being called the Whitaker quarry, by the way? It seems pointless to rename such a well known locality.
Now Cope's Coelophysis material was referred to three species, C. longicollis, C. bauri and C. willistoni. Hay (1930) designated bauri as the type species without comment. After a flawed attempt by Welles (1984), Colbert (1989 for C. bauri) and Hunt and Lucas (1991 for C. longicollis and C. willistoni) were the first to actually designate lectotype specimens from Cope's syntypes. C. longicollis' lectotype is the cervical vertebra AMNH 2701. Hunt and Lucas state-
"The lectotype of C. longicollis is not diagnostic beyond the level of a primitive theropod, and we consider the taxon a nomen dubium. In so concluding, we emphasize that whichever of COPE'S syntypes of C. longicollis is chosen, it a nomen dubium, because none of the syntypes are diagnostic."
 |
| Lectotype of Coelophysis longicollis (AMNH 2701)- anterior cervical vertebra in lateral (a), ventral (b) and anterior (c) views (after Huene, 1915). Note anterior pedicular foramen to left of neural canal in c. |
Just as with most declared nomina dubia, a brief statement without any comparison is deemed sufficient to make a taxon indeterminate. Yet anyone who saw AMNH 2701 could note it's certainly not just a primitive theropod. If nothing else, its elongation is only seen in derived coelophysoids. Beyond that though, today I noticed it has anterior pedicular foramina. These are so far only known in Coelophysis bauri, and are absent in "Megapnosaurus" kayentakatae and the Shake-n-Bake coelophysid for instance. Tykoski (2005) considered them autapomorphic for C. bauri, though he noted the condition in Megapnosaurus is unknown due to the brief description.
Interestingly, C. longicollis was based on more specimens than C. bauri, which were more complete than those of the latter species, was larger, and was described first in Cope's paper. It could have easily ended up being the type species of Coelophysis if not for Hay's seemingly arbitrary decision. And in that case, the type of Coelophysis would have been diagnostic after all, making the neotype designation unecessary. As it is, Coelophysis and its type species bauri are both based on a complete Ghost Ranch skeleton now, so it doesn't even matter if the bauri lectotype (an incomplete sacrum and ilial fragment) are diagnostic. But longicollis can now be made a synonym of bauri at least with evidence besides the assumption all of Cope's material belonged to one taxon.
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