Long needed redescription of the type material of the phytosaur Parasuchus hislopi from India and a revision of the non-mystriosuchin parasuchid phytosaurs. It will take me awhile to abandon the name Pseudopalatinae.
Kammerer, C. F., Butler, R. J., Bandyopadhyay, S., and M. R. Stocker. 2015. Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885. Papers in Paleontology (early online).
Abstract: The neotype skull of the Indian phytosaur
Parasuchus hislopi Lydekker, 1885 (ISI R42) is re-evaluated and compared with the type material of other basal phytosaurs.
Parasuchus hislopi is extremely similar to species previously placed in
Paleorhinus (
P. bransoni and
P. angustifrons), sharing with them such characters as a series of nodes on the lateral surface of the jugal, paired ridges on the squamosal and a frontal depression.
Parasuchus hislopi represents a valid species: it can be distinguished from
P. bransoni by a relatively low narial eminence and
P. angustifrons by the absence of paired nasal depressions. Inclusion of
Parasuchus hislopi in a phylogenetic analysis of phytosaurs recovers it in a well-supported clade with
P. bransoni and
P. angustifrons.
Parasuchus is considered the senior synonym of
Paleorhinus and
Arganarhinus.
Parasuchus (here considered to include
P. hislopi,
P. angustifrons,
P. bransoni and
P. magnoculus) has a broad circum-Pangaean distribution, with species occurring in the south-western United States, Morocco, central Europe and India. Phytosaur higher-level taxonomy is also revised: Parasuchidae is redefined to include ‘
Paleorhinus-grade’ phytosaurs and the later-diverging Mystriosuchinae (the group formerly known as Phytosauridae), and Pseudopalatinae is renamed Mystriosuchini for reason of priority.
The authors make a flawed argument to keep Parasuchidae Lydekker, 1885 over Phytosauridae Jaeger, 1828 however. They argue because Phytosaurus is too fragmentary to refer to the restricted definitions of Phytosauridae by Doyle and Sues (1995) or Stocker (2010), that we can't use Phytosauridae and should instead use Parasuchidae. They then provide a more inclusive definition for the latter family.
ReplyDeleteBut wait! The use of Phytosauridae isn't tied to the definitions that have been proposed so far. Phylocode isn't even implemented yet, and neither definition would be valid under it because they don't include the eponymous Phytosaurus cylindricodon. If we rejected clade names because their first definitions were trash, we'd lose a lot of names (e.g. Ornithomimidae as "Ornithomimus velox <- Erlikosaurus andrewsi" or Tyrannosauridae as "Tyrannosaurus rex <- Alectrosaurus olseni, Aublysodon mirandus, Nanotyrannus lancensis", both from Sereno 1998).
Phytosaurus falls within the known content of Kemmerer et al.'s Parasuchidae, which they admit themselves. According to the ICZN, any family containing both Parasuchus and Phytosaurus must be called Phytosauridae, as it was named earlier. Thus Phytosauridae should be used if we're treating known parasuchians as one family, and Kammerer et al. should have provided a new definition for it instead (e.g. "Phytosaurus cylindricodon + Parasuchus hislopi + Wannia scurriensis + Mystriosuchus planirostris").
Also note their definition of Phytosauria, which is from Nesbitt's 2011 study, is invalid because it doesn't use the eponymous Phytosaurus cylindricodon as an internal specifier, using Rutiodon carolinensis instead. In this case, the ICZN doesn't have jurisdiction, but why not use Parasuchia instead which was proposed twenty years before Phytosauria AND is based on a diagnostic taxon? Just define it as "Parasuchus hislopi <- Aetosaurus ferratus, Crocodylus niloticus", and there ya go.
Why do people have such a hard time following the rules of the ICZN and Phylocode?
You are mistaken in your interpretations here. Phytosaurus cylindricodon can NOT be demonstrated to fall within our Parasuchidae, and we absolutely do not state that it does. The type series for this species is incredibly poor. If you were to take one of the isolated teeth, and put it into the phylogeny, yes, you could say it is a phytosaur, that is, closer to known phytosaurs than other archosauriforms. But you can't say that it falls within the node-based clade Parasuchidae (Wannia+Parasuchus+Mystriosuchus), it could easily fall outside of it! They are not identifiable as "derived" phytosaur teeth, the same morphology is seen in the posterior teeth of Parasuchus, for instance. The jaw fragment with filled-in alveoli (source of the name Phytosaurus cylindricodon) is even worse. Yes, since it is Late Triassic it is almost certainly a phytosaur...but on a strict apomorphy basis one cannot say with certainty that it is not a crocodilian or even a platyoposaurine temnospondyl--it's that bad. Certainly not that it falls within (and this is important, because we want a robustly established node in which to place future phytosaur discoveries in Parasuchidae) the clade Wannia+Parasuchus+Mystriosuchus. We considered these issues carefully, and we included several paragraphs of discussion specifically to cut off complaints just like this, but it seems they fell on deaf ears. This is not a Titanosauridae situation, where even if the genus is dubious the type specimen clearly falls within the clade as defined. Our whole point is that by using Phytosaurus cylindricodon as specifier you get a clade of highly unstable content--although our Parasuchidae and Phytosauria are CURRENTLY compositionally identical, they are defined such that this will not be the case forever (and indeed, this distinction should be put into play soon...) Taxonomy must serve science, not the other way around--we should not compromise the utility of a clade name to preserve a historical nomen.
ReplyDeleteAlso, I am not a big fan of the Phylocode, but I take the ICZN very seriously. Phytosauria is not a family-level taxon, and as such it is not tied to a typological concept like type genus. Even though many 19th century names like Phytosauria were established as "families", as soon as Phytosauria and Phytosauridae were made separate taxa the link between Phytosauria and the typological system was broken. That's like ICZN 101. Now, I strongly prefer to define taxa based on their originally-included content, but that does not make Nesbitt's definition "invalid." Also, although I think anything based on the name "Phytosaurus" is a terrible, inaccurate name (and why I did not want to bend over backwards to save Phytosauridae), the fact of the matter is Phytosauria is entrenched and here to stay--many have tried to replace it with Parasuchia in the past and it just didn't stick, so we've got to deal with it.
-Christian Kammerer
Thanks for the quick reply. Your arguments here are different from that in your paper though, where you state "The argument could be made that regardless of the status of Phytosaurus as a nomen dubium, if it exhibits the diagnostic features of the larger clade currently called Phytosauridae, then the latter taxon could be retained. However, the type material of Phytosaurus cylindricodon does not exhibit any synapomorphies of Phytosauridae sensu Stocker (2010): it can be identified at best as Phytosauria indet. (based on age and general morphology; these specimens do not actually preserve any of the synapomorphies of Phytosauria recognized by Nesbitt (2011)). As such, the name Phytosauridae cannot be utilized to refer to this clade and must be considered dubious in and of itself." But here you're saying that because Phytosaurus doesn't have a stable position within Phytosauria, and that a purely anatomy-based analysis couldn't resolve it as a member of that clade, it shouldn't be used for _any_ definition, not just Stocker's definition.
ReplyDeleteRegarding its unstable position, note I said Phytosaurus falls within the _known_ content of your Parasuchidae, which you agree with here too. If it happens to fall just outside (Wannia+Parasuchus+Mystriosuchus), then the family's content would expand. So it's like Hadrosaurus, which could be outside the lambeosaurine+saurolophine clade (Prieto-Marquez, 2011) or inside 'Saurolophinae' (making that subfamily Hadrosaurinae; Xing et al., 2014). Yet Prieto-Marquez still uses a Hadrosauridae defined as including Hadrosaurus. I can understand why you'd prefer compositional stability over historical stability, but it's still just a preference. I figure if you want compositionally stable clades in Phytosauria, you can just phylogenetically define unranked clades too and thus have it both ways.
As for Phytosaurus not being phytosaurian, my first reply would be that if that turned out to be the case, you wouldn't want to keep calling the clade Phytosauria anyway. You do say here you don't like the name but that it's "here to stay", yet I think people would abandon Phytosauria if it was discovered Phytosaurus was a crocodilian or something. But if we're comfortable enough to call the stem-based clade Phytosauria, knowing we'll have to rename it if Phytosaurus turns out to be something else, it follows we should be comfortable enough to call the family Phytosauridae.
continued...
DeleteIn any case, assuming the partial mandibles shown in Plate VI, figure 3 of Jaeger (8128) are the type, Phytosaurus does have a phytosaurian apomorphy listed in Nesbitt (2011), contra your paper- "Dentary-splenial mandibular symphysis present along one-third of lower jaw (160-1)." And Nesbitt isn't the exclusive source of phytosaur apomorphies, as their monophyly is pretty obvious so wasn't being tested much by his matrix. You could throw in the extensive splenial participation in the symphysis, highly elongate dentary with over 28 teeth, and the lack of much labiolingual compression of the teeth as characters not seen in many basal archosauriforms too. AFAIK Platyoposaurines have a precoronoid involved in the symphysis as well as the splenial, so don't match Phytosaurus.
But perhaps my main point here should be that limiting yourself to using anatomical apomorphies to classify something is a restriction that's not necessary to follow. Stratigraphic placement is a clue often used by authors (e.g. why half of Chatterjee's Triassic taxa are automatically suspicious), as are other non-anatomical characters such as behavior, genetics, etc.. So you're basically arguing that if we ignore a subset of data, Phytosaurus may not be a phytosaur, which doesn't seem like a useful argument.
Finally, Nesbitt's definition _would_ be invalid under the PhyloCode for not following Article 11.7- "when a clade name is converted from a preexisting typified name or is a new or converted name derived from the stem of a typified name, the definition of the clade name must use the type species of that preexisting typified name or of the genus name from which it is derived (or the type specimen of that species) as an internal specifier." You say you're not a big fan of the PhyloCode, which is fine, but it will be what determines the validity of phylogenetic definitions as much as the ICZN determines the validity of family- to species-level ranks.
You are still misinterpreting things, and conflating Phytosauridae (of which I do not advocate usage) with our version of Parasuchidae (which I obviously do). I do not agree with the statement that Phytosaurus cylindricodon falls within the known content of my Parasuchidae. Parasuchidae is NOT defined as “all known phytosaurs” (although it currently includes all *valid* phytosaurian genera), it is defined as Wannia+Parasuchus+Mystriosuchus. If Phytosaurus falls outside of this clade, then Parasuchidae does not expand to include it. That is the entire point of not defining this clade based on Phytosaurus! I do not see what is so difficult to grasp there. You say, “If you are confident in Phytosauria, you should be confident in Phytosauridae”. Nonsense. If you are confident something is a crocodylomorph, does it follow that it is a crocodylid? For reductio ad absurdum, “If you are confident a specimen is in Eukaryota, you should be confident it is Homo sapiens.” Let us assume a future where additional work has established a robustly-supported position for the P. cylindricodon mandible outside of the clade Wannia+Parasuchus+Mystriosuchus. In that case, it is not a parasuchid, full stop. It of course remains a phytosaurid, but in that case the monotypic Phytosauridae and Parasuchidae would be sisters on the tree (well, not really, because parasuchids are node-based, but you get my meaning). And if future work robustly supports P. cylindricodon being nested within our Parasuchidae? Well, then we can talk about subsuming Parasuchidae as a junior synonym of Phytosauridae. Just as if Phytosaurus is not a phytosaur we could consider abandoning Phytosauria.* But these possibilities are unlikely, and at present we would like to deal with taxa that actually mean something.
ReplyDelete*(Aside: I agree entirely from the age that Phytosaurus is what we call a phytosaur. I am not ignoring that data. But you are being hypocritical here, as things like geographic location and stratigraphic position, while obviously data of import in making decisions as to specimen referrals, are not and cannot be the basis for taxonomic diagnoses under the Code [Art. 12.3], and, following from that, definitions based on typified taxa. Are you certain that there is not a precoronoid bone behind the broken-off part of that jaw, or that the poorly-preserved tooth row edge is not a splenial-dentary suture rather than a ridge on the dentary symphysis? Devil’s advocate here, I reiterate that I do not believe it is anything other than a phytosaur. But for this particular argument we must restrict ourselves to anatomy. The draft PhyloCode does not have provisions for stratocladistic definitions, I would note).
See, the thing is, at the end of the day taxonomic names are words, and the reason we have words is to convey information. If a word cannot convey information, it is worthless. I fear that some like yourself, in your desire to foster ideological purity in nomenclature based on personal opinions of how things “should be done”, lose sight of practical utility for these words. You might argue, “Oh but Phytosauridae does contain information, it contains information that these are things associated somehow with Phytosaurus”, but who does that benefit? Certainly not phytosaur workers, who have been laboring with a byzantine, confused taxonomy for decades that we are only now unraveling and making useful. Or other scientists, non-specialists on the group, who would like a clear and easily-defined taxon for the referral of material, museum organization, education, or taxonomic boundaries for meta-analysis. Perhaps you are just complaining for complaining’s sake, and have no interest in improving phytosaurian studies. I note no comments to the effect of, "Good to finally have Parasuchus hislopi sorted out" or even “Hey, that taxon Pseudopalatinae was really messed up from both an ICZN and PhyloCode perspective, good work fixing that”, solely the snide gnashing of electronic teeth into the internet aether.
As for the PhyloCode and Phytosauria, you throw around absolutes like “this name is invalid” when we are talking about hypothetical scenarios. Therein lies the problem for discussing “rules” of the PhyloCode: they don’t exist, because this code exists only as a proposed draft, not anything that can be referred to as definite legal text. The Article you cite did not exist in the original draft version of the PhyloCode, and we cannot be certain it will exist in the one that is eventually implemented (if, indeed, such a thing ever occurs. Based on its current rate of gestation, I am not optimistic). Indeed, I am uncertain whether it exists in the current version! (not that I doubt it does, just that the official website only hosts version 4, not the current version 5 that it claims will be posted “soon” despite having been completed in January 2014). Perhaps folks like myself, who are pro-phylogenetic nomenclature (I wrote an entire paper on its application to fossil synapsid groups, see Kammerer & Angielczyk, 2009. Zootaxa, 2018, 1-24) but anti-PhyloCode as it stands, will try for an active role in the ICPN rather than writing it off as foolishness, and seek to impose some of our preferences on future versions. Again, hypotheticals—in the absence of a formally established code we just can’t say.
ReplyDeleteBut let us address the Article in question as it exists in version 4. The requirement to use type species as specifiers for taxa directly converted from rank-based codes is obvious: type species becomes specifier, ideally approximating traditional usage. It is with the additional caveat “or derived from the stem of such a name” where we get into trouble, however. I think you will find this can become far more difficult and prone to interpretations than is desirable. Many widely-used historical names, established at the dawn of modern nomenclature, lack stated etymologies and their direct connections to specific genera can be vague. Take the established higher-level names for turtles. Is Testudinata based on the generic name Testudo and is Chelonii based on the generic name Chelonia? It may seem, on the face of it, to be an obvious “yes” based on their construction, but really it is very unclear. Testudinata Oppel, 1811 postdates Testudo Linnaeus, 1758, so one might think it would be based on that name. Chelonia and Chelonii, on the other hand, are part of a whole mess of taxa variously derived more or less simultaneously from the French informal (but intended as taxonomic and treated as such by the Code) Chéloniens. Keep in mind that testudo and chelone are also just the Classical words for tortoise and turtle, and were used outside of a modern taxonomic context for centuries in natural historical literature. You may say, “But Linnaeus put all turtles in Testudo, so as the only turtle genus originally recognized, Testudinata must be linked to it.” Not so fast! Oppel (1811) cited Testudinata as having been established by Klein (1751), meaning its origins are pre-Linnaean (in the sense of the Code; Linnaeus had of course established his first version of Systema Naturae—including the genus Testudo—in 1735). Notable here is the fact that Klein’s other divisions of herptiles, Nuda and Cataphracta, are not tied to specific genera, which suggests (but does not prove) the general Latin term was meant. [As an aside, I should note here that several of the architects of the PhyloCode (Joyce et al., 2004, “Developing a protocol for the conversion of rank-based taxon names to phylogenetically defined clade names, as exemplified by turtles”) grievously violated the rule we are discussing throughout that paper, defining both Testudines (whose origin was literally just a pluralization of the genus name Testudo, later misinterpreted as a higher-level taxon, so in this case the original intent is clear) and Testudinata using Chelonia mydas and Chelus fimbriatus as specifiers. At the time they were operating under an earlier version of the PhyloCode that did not contain this provision, yet their definitions have become quite entrenched in the literature, so I guess we will see if they alter them in their chapter for the “companion volume”.] Hopefully I have established that for the aforementioned taxa it is a confusing situation, and there are dozens if not hundreds of comparable examples from the chaotic early days of nomenclature. For this reason, I would argue that it is a bad idea to have a Rule (rather than a Recommendation, which I would support) requiring any taxon based on another taxon name to include the latter’s type as specifier. You could argue, “Okay, in that case let’s say that in cases of uncertainty we assume a name is not based on a specific genus by default”, but the nature of uncertainty is that it forms a slippery slope that is not ideal for a formal set of regulations.
ReplyDeleteGiven the aforementioned issues, I do not think it is unreasonable to suggest that the same proviso be waived for well-known names based on dubious species. I can tell from this discussion that you are eager to die on the hill of “Ceratopsia must be defined as >Ceratops montanus but not Pachycephalosaurus wyomingensis”, but I have my doubts that the majority of dinosaurologists will follow you into that fight when Triceratops horridus is right there. Let me bring up another example, of a taxon near and dear to my heart: Dinocephalia Seeley, 1894. Seeley’s higher-level synapsid taxa are based on specific genera: Gorgonopsia on Gorgonops Owen, 1876, Kistecephalia on Cistecephalus (originally spelled Kistecephalus) Owen, 1876, etc. And yes, Dinocephalia was based on a genus Dinocephalus. However, for whatever reason, Seeley never got around to describing Dinocephalus (it appears only in list format, without reference to any specimens or illustrations thereof) and it is a nomen nudum. Dinocephalia is, without a doubt, based on a dubious name of uncertain attribution—must we then junk it? Because let me tell you, that’s not going to happen. You may say, “Ah, but if it is a nomen nudum then Dinocephalia is not based on the “stem of a typified name” and it is exempt from this rule”. But is that really how we want to run things as we move nomenclature forward, trusting in the provisos of legalese instead of fostering names based on usage? This statement may seem hypocritical coming from me, an ICZN hard-liner who has in past papers overturned an array of suprageneric names “in prevailing usage” on the basis of priority. Rules are important, and I share your dismay at many in paleontology regarding them so cavalierly. But there comes a point where you have to think hard about whether you are doing something because a rule says so, or because it is beneficial for fostering scientific advancement. And if the former actively hinders the latter, why you are so doggedly determined to uphold it. And ESPECIALLY if the rule in question doesn’t even exist yet, and can be changed or reconsidered because of situations just like these.
ReplyDeleteAnd I thought my reply was long. ;) I think there a few misunderstandings. Also, let me say that I do sometimes (often?) come across as overly critical, because I think critiques of papers are more useful to point out in most cases than compliments. But I did think your paper was overall well done, a needed step in sorting out the group, and I even followed your taxonomy for derived phytosaurs on my website. Since you're in Germany, it'd be really cool if you redescribed Phytosaurus fully, so we didn't have to depend on brief assertions or 187 year old descriptions. But as for our discussion...
ReplyDeleteI'm not conflating your version of Parasuchidae with my suggested version of Phytosauridae. I agree Phytosaurus may not belong to your Parasuchidae. That's why I suggested a definition for Phytosauridae that is potentially more inclusive, depending on where Phytosaurus goes.
You say you "do not agree with the statement that Phytosaurus cylindricodon falls within the known content of my Parasuchidae", but by "known content" I only meant that there are no described phytosaurians agreed to be more basal than Wannia, and that you agree Phytosaurus is probably phytosaurian. Poor wording on my part though, and I'm fine with dropping it.
By "If you are confident in Phytosauria, you should be confident in Phytosauridae", I only meant that if you are confident in using Phytosauria as a clade name, you should be confident using Phytosauridae as a clade name. Not a name for any particular clade, not for Stocker's definition, or your definition of Parasuchidae, just for a name somewhere within Phytosauria. It was meant as an argument against "we shouldn't use Phytosauridae because Phytosaurus may be a crocodilian or platyoposaurine instead."
(To your aside: I don't think the Article 12.3 is relevent here. Just because we can't erect a taxon based solely on its geological horizon does not mean we can't use its age to help assign it to a group, and then use the taxon in a definition of that group. Indeed, 12.3 states the geological horizon "in itself" cannot be used to erect a taxon, implying age could be used in concert with anatomical information to erect a taxon prior to 1930. But again, I don't think rules for erecting taxa matter here- after Phytosaurus and Phytosauridae were erected by following 12.3, we can now describe and diagnose them however we want as long as they contain P. cylindricodon. And yes, we can question the accuracy of any description or illustration [as we speak, I'm questioning Wang et al.'s interpretation of their new enantiornithine Pterygornis' surangular- I think its in medial view and upside down, so that the anterior slope would match other theropods and the supposed angular is the dorsal Meckelian fossa margin], but I think we both agree that unless we find reason to doubt a feature, just saying it could be wrong is unhelpful.)
Regarding the Phylocode, I accept that "would be invalid under the current draft if it was implemented" is a more accurate statement than "would be invalid." I also don't like all aspects of the PhyloCode, such as "the application of widely known names to crown clades and forming the names of the corresponding total clades by adding the prefix "Pan-" to the name of the crown." Similarly, I share your pessimism regarding PhyloCode's gestation period.
ReplyDeleteGiven all of that, I do feel this particular rule is a very good one though, and would want to replace Chelonia mydas with Testudo graeca in Testudines' definition, for instance. You're also right that I would die on the hill of that definition of Ceratopsia, and you predicted exactly what I was going to say in the case of Dinocephala (interesting to learn that history though). But I think you and I agree that while we should in general follow the "legalese", that if it's problematic to do so then that's what the ICZN and (eventually hopefully) CPN are for. The ICZN has decided over 2000 disputes and exceptions, and the CPN will probably be no different. They can then declare that "all variants of Cheloni- are to be considered eponymous with Chelonia Brongniart, 1800" or that "Rutiodon carolinensis Emmons, 1856 is to be considered the necessary internal specifier of Phytosauria Jaeger, 1828." It's the very fact that Dinocephalia works out with the legalese that makes adhering to it fine in that case. Similarly, it's the fact basing Phytosauria on Phytosaurus works out (because we all agree Phytosaurus is in stem-based Phytosauria) that I'm determined to uphold the albeit unimplemented rule in that case too. Maybe there will be a case in the future where a clade's usage is _so_ well established that even though we discover its eponymous genus doesn't belong in it, we still want to keep the clade name. In that situation, sign me up for ignoring the rule for that clade, pending a CPN petition, but Phytosauria and Ceratopsia aren't it.
In (?)conclusion, if your paper would have said... "Because Phytosaurus has an uncertain position within Phytosauria, we prefer the compositional stability of not using any definition for Phytosauridae over following the principle of priority and defining a less precise clade as Phytosauridae. Thus we use Parasuchidae for the family containing the known diversity of valid phytosaurs, recognizing Phytosaurus and Belodon may belong to that clade." ... I probably wouldn't have written my comment. And if you would have thrown in word of an ICZN petition to suppress Phytosauridae and Belodontidae for Parasuchidae, even better. Though then I'd probably be complaining about dismissing Phytosaurus before it has been redescribed in a modern context. ;)
It's not a matter of ignoring priority, though--it's a matter of the ICZN regulating nomenclature, but leaving scientists a broad degree of taxonomic freedom. This includes the freedom to determine the boundaries of ranked taxa such as families, with the possible effect being that some nominal family-level taxa become nomina dubia if your preferred circumscription of 'family' is narrow (just as some of Linnaeus' broad genera, like Medusa, became dubious when more restrictive generic concepts were applied and Linnaeus' vague species could not be assigned with certainty to the new morphogenera). I could have gone with even smaller 'families' (like recognizing Parasuchidae, Angistorhinidae, Rutiodontidae, Leptosuchidae, Mystriosuchidae, etc.) to ensure such an outcome, but preferred to go with a circumscription with more historical precedent (but which still leaves Phytosauridae and Belodontidae of dubious application at the present time). I'd be the first to admit this could change with more research, and I wouldn't dream of petitioning for suppression of Phytosauridae or Belodontidae right now, we just don't know enough. At the moment, I am confident that their type specimens are not diagnostic beyond Phytosauria based on macro-scale external morphology, and that Parasuchidae is the way to go to ensure stability of composition. This said, who knows what a CT-scan of the P. cylindricodon mandible, or SEMs of Belodon teeth (at least those that haven't been lost) might yield? Resurrection of ignored historical taxa is kind of my bag (see, e.g., Kammerer, 2014, 2015; Kammerer & Angielczyk, 2009; Kammerer et al., 2011, 2013, 2015), so I could see tackling this problem eventually. But I've got 108 gorgonopsian species to revise first...
ReplyDeleteFair enough re: gorgonopsians. Might I unselfishly suggest you next tackle Dinosaurus murchisoni, so that I can have a more authoritative comment on its status in the Theropod Database? ;)
ReplyDelete