Tiny pterosaurs and pac-man frogs from hell

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It was Beelzebufo that finally made up my mind. Long-time readers will have noticed that I generally fail to discuss the exciting stuff that's being announced in the news, even when it's very much relevant to the Tet Zoo remit. Indeed some of you have even commented upon this fact. What's my excuse for this? Well there are a few actually...

-- For starters, once I've decided to blog about something - say, initial bipedalism or European pumas or liolaemine lizards - I need to stick with it and get it out of the way. Because I have a long list of subjects that I plan to blog about, I am not looking around for things in the news to write about, as seems to be the case for so many bloggers (no disrespect intended). In other words, I'd rather do my own thing thank you very much (incidentally, this explains why I can't be bothered with memes anymore*).

-- Furthermore, let's face it, most of the scientific stuff that's announced in the news isn't really news in the substantive sense: a lot of it amounts to 'we found a new one'. Cases in point are the mummified hadrosaur named 'Dakota' - splashed all over the news and yet to make a debut in the technical literature - and the giant pliosaur from Jurassic sediments of Spitsbergen, informally dubbed 'the monster'. I'm not saying that these announcements don't have merit, just that there is bugger all to say should you wish to try and write about them.

-- Finally, there's also the point that high-profile stuff announced in the media is already going to be discussed by scores of other people, and if you do chose to write about such stuff you're just one in the crowd, nothing special. And, come on, we all know that you come to Tet Zoo because you read stuff that you don't get elsewhere (hmm, that sounds very arrogant. But still true).

* Though I am still sincerely grateful when people think of me when meme-spreading.

So now you know. Sure, there often are new discoveries or announcements that get me excited, and excited enough that I end up covering them here. And in an effort to redress the general lack of newsy-type coverage at Tet Zoo, I made an effort in February to write an article on 'new stuff in the world of Tet Zoo'. Sengis, deinotheres, abelisaurs, lambeosaurs, uakaris, giant frogs. Alas, it then got shelved and hence is no longer new, plus (see above) it's all been splashed around the internet already. But what the hell. Here are assorted thoughts on a few recent discoveries: I also wrote about dinosaurs and fossil and living mammals, but have held those parts back for other articles. We begin with Beelzebufo ampinga, the large Cretaceous anuran described last month by Susan Evans and colleagues.

Beelzebufo: giant Cretaceous pac-man frog from hell

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Given that all Tet Zoo readers are now experts on the phylogenetic diversity and classification of anurans (except perhaps for natatanurans, the one group I have yet to finish writing about), it will have been widely realised that Beelzebufo is a ceratophryid hyloid neobatrachian (go here and here). Its identification as such is based on its thickened, rugose skull roof bones, the projecting shelf on the parietal at the rear margin of the skull, and on other characters of the jaws and teeth (Evans et al. 2008). While it resembles the living Ceratophrys and Chacophrys in its interlocking premaxillary-maxillary articulation, it differs from all other ceratophryids (or ceratophryines) in its over-developed pit-and-ridge cranial sculpturing, in the persistence of cranial sutures, and in its much larger size [adjacent reconstruction shows Beelzebufo to scale with... a pencil.. and Madagascar's largest extant frog, the mantellid Mantidactylus guttulatus].

On size, large individuals of Beelzebufo are estimated at having been about 20 cm wide across the back of the skull, and with an SVL (snout to vent length) of about 42 cm. This is immense, but note that most specimens are smaller (a mere 8-12 cm across the skull, SVL estimated at 16-27 cm). Evans et al. (2008) noted that, in extant ceratophryids, juveniles and males are commoner and smaller than the really big females, and what we know of Beelzebufo suggests a similar population structure. Beelzebufo was huge, but was it the biggest anuran? That's difficult to answer. An SVL of c. 35 cm has been reported for Calyptocephalella parodii from the Miocene of Argentina (a close relative of the Helmeted water toad [shown below] I wrote about here), 36.8 cm has been published for the Goliath frog Conraua goliath, and 38 cm for the Cane toad Rhinella marina. While cane toads are short-legged and might therefore be similar in weight to a giant Beelzebufo, the proportionally longer legs of Calyptocephalella parodii and Conraua goliath might mean that giant specimens of these species would be heavier than a giant Beelzebufo. Maybe all of these species max out at about the same size: the record-holding Goliath frog (captured in 1989 on the Sanaga River in Cameroon) weighed 3.66 kg (with legs extended it was 87.6 cm long). Of course it would be possible to scale up the weight of an extant pac-man frog to Beelzebufo size to get an estimate, but I'm not exactly the best person to do that so will leave it to someone else.

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Note that, in contrast to so many fossil anurans, Beelzebufo is actually pretty well represented: it's not based on a single ilium or a few skull fragments, but in fact on over 60 bones collected from 26 different localities (all within a 1.8 km radius). I wonder if this means that it was relatively common in its environment (Beelzebufo is from the Maastrichtian Maevareno Formation: the Madagascan unit that, among others, has yielded the amazing crocodyliform Simosuchus, the sauropod Rapetosaurus, and the theropods Majungasaurus, Rahonavis and Vorona).

Living ceratophryids (like the Ceratophrys shown below) are lurking ambush predators that bury themselves in the substrate and sit there, awaiting prey. They lunge at passing animals, subduing them with strong, heavily ossified jaws and sharp teeth, and their immense mouths (which have earned them the popular name 'pac-man frogs') allow them to cram reasonably big vertebrates down their throats. It's reasonable to think that Beelzebufo behaved in the same way, and its large size would have made it a formidable predator of small vertebrates. If it was reasonably common, were parts of the Maastrichtian Madagascan forest floor veritable mine-fields of giant pac-man frogs?

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Finally, the presence of Beelzebufo in Maaschtian Madagascar opens up questions about anuran biogeography, given that the presence of a ceratophryid there is totally unexpected. To cut a very long story short, ceratophryids on Madagascar provide support for models where a connection between Madagascar and southern Gondwana persisted until the Late Cretaceous: this suggests that ceratophryids were widespread across southern Gondwana during the Cretaceous, and that their restriction today to South America results from extinction elsewhere in the southern continents. Next time you're on Antarctica, try and find a fossil ceratophryid. Incidentally, Beelzebufo - in its original incarnation as the 'hyperossified megafrog' - was first mentioned on Tet Zoo ver 1 back in January 2006 (here). So as usual, you should be able to say that you heard it here first.

Nemicolopterus: alleged ptiny pterosaur

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Moving now to something entirely different, the last several weeks have been particularly exciting if you're interested in pterosaurs although, what with a couple of projects that Mark Witton and I are currently working on, I do admit to having pterosaurs on the brain at the moment. Anyway, firstly we have little Nemicolopterus crypticus, a small pterosaur from the Jiufotang Formation of Liaoning Province, China (Wang et al. 2008). Represented by a near-complete skeleton [shown above] that has an estimated wingspan of about 25 cm, Nemicolopterus is toothless, with a subtriangular pointed rostrum and elongate, curved penultimate pedal phalanges. The latter feature strongly suggests arboreal habits for this little animal (Wang et al. cite a study on the toe bones of sloth lemurs here, which is fair enough as I might have done the same).

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However, I do admit to being sceptical of many of the claims made by Wang et al., and indeed thoughts similar to mine have been mentioned already by other people in the pterosaur research community. Its small size, proportionally big skull and large rounded orbit suggest that it might be a juvenile of something else, and given that multiple specimens from the same deposit appear to represent growth stages of a rather similar pterosaur (the tapejarid Sinopterus), it is likely that Nemicolopterus is a baby Sinopterus. Wang et al. note that N. crypticus is juvenile-like in displaying unfused cranial bones, and only go as far as saying that it was 'not a hatchling that had just left the egg' (p. 1986). Well, we already know from other taxa that pterosaurs were precocial as youngsters, and that juveniles acted as separate 'eco-species' from their parents (Unwin 2006), so given all of this it seems reasonable to assume that N. crypticus was not a specialised mini-pterosaur as has been inferred, but a juvenile with a lot of growing to do [adjacent image is John Conway's skeletal reconstruction, go here for bigger version].

Furthermore, while Wang et al. (2008) found N. crypticus to be the sister-taxon to a pterodactyloid clade that included ornithocheiroids, dsungaripterids and azhdarchoids, several of its characters (e.g., its proportionally short distal-most wing phalanx, ventrally extending 'pear-shaped' orbit and ventrally deflected rostrum) seem to better support its inclusion among azhdarchoids, and within tapejarids. One claim made by Wang et al. about N. crypticus is downright odd: they state that big ornithocheiroids and so on 'originated from crestless and toothless small insectivorous arboreal forms', like N. crypticus. The re-evolution of teeth would be interesting (do you recall previous comments on this stemming from Michael Fastnacht's talk at the Munich pterosaur meeting?). However, Wang et al.'s cladogram offers no support for this possibility: based on their findings, it is far more likely that N. crypticus is a specialised oddball, as it's off on its own in their cladogram, surrounded by big taxa, some of which (the nyctosaurids, ornithocheirids and pteranodontids) were oceanic.

Whatever, it's still an awesome specimen and I'm happy to see it in the literature [image at top of article was produced by Mike Skrepnick].

Finally on pterosaurs, Andres & Ji (2008) have just published yet another new Liaoning Province taxon: Elanodactylus prolatus (though, unlike Nemicolopterus, it's from the Yixian Formation). Particularly long wing phalanges indicate that Elanodactylus had long, slim wings, and this explains the generic name (Elanus is the black-shouldered kite genus). The big deal about the paper is that it includes yet another new cladistic analysis of pterodactyloids, and it includes some surprises to say the least: among these are the inclusion of lonchodectids among ornithocheiroids and dsungaripterids within the azhdarchoids. Andres and Ji say lots of other interesting things in their paper; not least is their discussion of alleged Jurassic members of Azhdarchidae and what these specimens imply for the azhdarchid ghost-lineage. We'll come back to all of this in the future.

And I have to stop there. I was going to talk about new dinosaurs, but it'll have to wait. I have become horribly ill. Gave a talk last night on fossil elephants, but that wasn't to blame.

Refs - -

Andres, B. & Ji, Q. 2008. A new pterosaur from the Liaoning Province of China, the phylogeny of the Pterodactyloidea, and convergence in their cervical vertebrae. Palaeontology 51, 453-469.

Evans, S. E., Jones, M. E. H. & Krause, D. W. 2008. A giant frog with South American affinities from the Late Cretaceous of Madagascar. Proceedings of the National Academy of Sciences 105, 2951-2956.

Unwin, D. 2006. The Pterosaurs from Deep Time. Pi Press, New York.

Wang, X., Kellner, A. W. A., Zhou, Z. & Campos, D. de A. 2008. Discovery of a rare arboreal forest-dwelling flying reptile (Pterosauria, Pterodactyloidea) from China. Proceedings of the National Academy of Sciences 105, 1983-1987.

More like this

Wonderful post! Note how gracefully I take the well deserved slap for being one of those low-brow pedestrian types that want to hear an experts take on the latest (to me )dinosaur news.

And yes there ARE dozens of people cutting and pasting about these topics, but their views are generally worthless. I would rather pester the people who really know what's going on.

By thylacine (not verified) on 19 Mar 2008 #permalink

As always, a great post to read. Hope you feel better soon, sir.

By Adam Pritchard (not verified) on 19 Mar 2008 #permalink

The more I look at Nemicolopterus, the less convinced I become that it isn't a juvenile Sinopterus. Looking at the--admittedly not very good--photos I have of Sinopterus, it even seems to have curved distal phalanges.

Which is all a shame, really, because I like Nemicolopterus.

I prefer fresh posts. News is already regurgitated again and again.

BTW, isnt one of special features of Nemicolopterus unique turning hindlimbs? If so, did Sinopterus have them? Lost in ontogeny?

BTW2 - anything about feeding mode of pterosaurs? Some at least might be kingfisher-like (for Australians: kookabura-like) pounce feeders.

Get well soon!

By Andreas Johansson (not verified) on 19 Mar 2008 #permalink

The idea of a Neo-Gondwanan province including South America, Antartica, Madagascar and India is even more stronger: frogs, abelisauroids, baurusuchids, gondwanatheres, turtles, titanosaurs.

I imagine the adult Sinopterus may have "grown out" of the curved pedal phalanges, although that's still a good question.

John, I just want to thank you for drawing that wonderful Nyctosaurus skeleton. It helped me enormously in restoring the beast for an upcoming art show.

Darren, if you have the Elanodactylus paper, could you send it my way? I'm always on the lookout for more pterosaurs.

"38 cm for the Cane toad Rhinella marina"

WHAT!!? i thought it was about half as big again to twice the size as our common toads - then again that explains where all the small marsupials are going in Queensland.

Ive been waiting to hear you thoughts on the small pterosaur (and marks too!)

Good posta nd get well soon :)

Would such a large anuran need unusual adaptations to be able to breathe, at some stage in its life?

By Nathan Myers (not verified) on 19 Mar 2008 #permalink

If Beelzebufo behaves anything like it's smaller modern relatives it would not be very active and I guess not have a very active metabolism - hence probably not very demanding from a respiratory point of view.
The Ceratophrys I used to keep was incredibly lethargic - it would go days with virtually no movement. The only turn of speed was the lunge it would make to engulf a cricket. Sometimes it even seemed as if it could barely be bothered to eat - sitting there with half a cricket sticking out of its mouth for a long while before deciding to finally eat it (often seeming to push the insect into its mouth with its front feet).
I'm told they are cannibalistic - the result of keeping 2 together often being the 'Ceratophrys moustache' (the back legs of one Ceratophrys hanging down either side of the mouth of the slightly larger specimen).

[from Darren: for some reason your message got delayed by the publishing platform, I only just noticed it]

By Mark Lees (not verified) on 19 Mar 2008 #permalink

The big deal about the paper is that it includes yet another new cladistic analysis of pterodactyloids, and it includes some surprises to say the least:

Well, sure. It's the first cladistic analysis of pterosaur phylogeny where neither Kellner nor Unwin are involved, isn't it?

What I'm surprised is that bigger cane toads than Goliath frogs appear to be documented. So the 40 cm I read for a Goliath frog were rounded up?

But in any case it's interesting that all those phylogenetically disparate XXL frogs seem to be within 5 cm of each other. Looks like there's something that limits their size. What could that be? I can't imagine it's breathing -- there are bigger lepo- and much bigger temnospondyls than that.

By David Marjanović (not verified) on 19 Mar 2008 #permalink

Another point of note, as I said on my brief post on the paper, is that their analysis is also notable for being larger proportionally (for the scope of its focus and number of characters) than those put out by Kellner or Unwin. :-)
It'd be interesting if someone would take the time to score _Nemicolopterus_ into Andres and Ji's matrix.

ceratophryid hyloid neobatrachian

Is the -id suffix no longer significant of a taxonomic family (-idae)? Do we loosen up on the sufiixes when using indented classifications?

I saw a talk recently by David Krause, one of the Beelzebufu guys, and he had lots of interesting Cretaceous tetrapod-fossil links between South America and Madagascar, including several mammals, crocs, and turtles.

that sure is a cute li'l pterofossil.

By Sven DiMilo (not verified) on 19 Mar 2008 #permalink

>Well, sure. It's the first cladistic analysis of pterosaur phylogeny where neither Kellner nor Unwin are involved, isn't it?">

Check out the list of characters in the Appendix. Nearly half of them are attributed to Kellner. Not surprising then that quite a lot of the underlying structure of the tree matches Kellner's 2003 effort and more recent manifestations such as, for example, in Wang et al. 2008.

Levering Lonchodectes into Ornithocheiridae is impressive, but pales somewhat when compared with the pairing of Dsungaripteridae with Tapejaridae+Tupuxuaridae to the exclusion of Azhdarchidae. Awesome!

By Dave Unwin (not verified) on 19 Mar 2008 #permalink

"and their immense mouths (which have earned them the popular name 'pac-man frogs') allow them to cram reasonably big vertebrates down their throats."
I'm reminded of something I saw on Animal Planet, one of those frogs attempting to eat another member of its own kind almost as big as it was!

Check out the list of characters in the Appendix. Nearly half of them are attributed to Kellner.

Only? :-)

Is the -id suffix no longer significant of a taxonomic family (-idae)? Do we loosen up on the sufiixes when using indented classifications?

I don't see what you mean. We simply declare Ceratophryinae to be a family, whereupon it automatically becomes Ceratophryidae. As long as someone publishes this, it's valid. This is not a matter of right or wrong; because the term "family" is meaningless, anyone has the right to declare anything a family, and anyone has the right to disagree with any such declaration. Nomenclature is not science.

Or were you talking about Hyloidea?

By David Marjanović (not verified) on 19 Mar 2008 #permalink

I completely agree that Wang et al. (2008) provide very little evidence that their new pterosaur isn't a juvenile. I also was very disappointed with their arguments for arboreal adaptations. Not to say that it couldn't have been arboreal, but they really don't do any rigorous comparisons. The least they could have done is throw ungual measurements into the dataset published by Glen & Bennett (2007).

Glen, C.L., and M.B. Bennett. 2007. Foraging modes of Mesozoic birds and non-avian dinosaurs. Current Biology 17(21):R911-R912. [Link to the Paper]

The idea that Nemicolopterus outgrew its phalangeal curvature and large claw-per-finger proportions as it grew is meritous, but the evidence for it being at least somewhat suspensory (previously supposed for some pterosaurs historically, anyway) may be indicative of changes in habitus throughout lifestyle. A free-moving scapula is somewhat needed for suspensory behavior, at least in mammals, though the anatomy of the arm appears in pterosaurs to accomodate the movements required nicely without using a rotating scapula.

By Jaime A. Headden (not verified) on 19 Mar 2008 #permalink

Well, as I really love it to calculate weights for animals I tried to calculate the weight of Beelzebuffo. The main problem was to find something to compare. As horned frogs have not really standard proportions of frogs and especially bigger ones can be extremely wide and fat for their length. But I could actually find some dates for comparisons.
For a young Ceratophrys cranwelli I found a weight of 44g at a SVL of 6cm. With this proportions it would weigh around 13(!)kg at 40cm SVL, but as it is a juvenile, the proportions are different to those of adults.
But I found also a size-weight relation of another specimen (note that this dates are from actual specimens, and not from books with dates of different origins).
A one and a half year old Ceratophrys cranwelli named Kassandra has a SVL of 9cm (and is 8cm at the widest part of its body) at a weight of 220g. What comes out when I use this dates looks really monstrous, because a frog with this proportions would weigh more than 19kg at 40cm SVL. This seems very extreme and I really don´t know what I have to think about this. I have seen last year some monstrous specimens of horned frogs, aga toads and goliath frogs at the NHM of Vienna, and they were really impressive (pictures here: http://bestiarium.kryptozoologie.net/artikel/moderne-riesenamphibien/ ) but they were all still far away from having a SVL of 40 cm. A frog with a SVL of 20cm is already gigantic but 40cm nearly impossible to imagine. Given their unusual proportions I could well imagine that Beelzebuffo was really well over any other living of extinct known toad or frog, even if the scaled-up calculations are too high.

I made a bit further research and used other dates for comparisons. Horned frogs are actually extremely heavy for their length and can have more than 2 times the weight of other frogs with the same SVL. One comparison I used was a bullfrog with 19,5 SVL and a weight of 875g (before feeding, after eating it weighed more than 1kg). Even this one would weigh around 7,5kg at 40cm SVL, but a frog like "Kassandra" would surely weigh much more.

Wow - thanks for that Markus, amazing. If Evans et al. had put some of this into their paper, the inference that Beelzebufo is the biggest anuran ever would clearly be justified. 19 kg? I am staggered.

In other news: wow, Jaime Headden lives. Where have you been Jaime?

I don't see what you mean

I was referring to the phrase "ceratophryid hyloid neobatrachian," which would seem to place it in both the family Ceratophryidae and the family Hyloidae.
As arbitrary as Linnean ranks are, they can't overlap. So is the -id suffix used for any old taxon, or does it still refer to a family, whatever that might mean?

By Sven DIMilo (not verified) on 21 Mar 2008 #permalink

It is probably also very dependent from their actual proportions. The giant horned frog I saw at Vienna was about 20-25cm in length, and I really did not know they could grow that large. But it was comparably narrow for a horned frog, not as obese as many smaller horned frogs I saw. Perhaps Beelzebufo was in fact more like the amazing african Pyxicephalus adspersus (which can also be extremely obese) than the south american horned frogs. I found maximum lengths of 24,5cm and a maximum weight of 1,4kg for Pyxicephalus adspersus, what is again problematic to interpret, as this proportions would lead to a much lesser weight. But I suppose that in this case as in many other similar cases the weights and lengths are not from the same specimens. Some size-weight-relations for alleged record-specimens of toads and frogs seems also highly doubtable. Up-scaling of animals with known weight and length does not work always if proportions differ. The 19kg figure seems really enormous, and it even does not count the possibility that this animals grew wider and fatter when they grew larger, as it can seen in many other horned frogs. Horned frogs are in comparison with other frogs and toads not very compressed, and this is probably one main reason why they can be much heavier than other frogs with the same length. BTW, here is a photo of "Kassandra": http://ceratophrys.pogona.ch/
I have seen already photos of much "wider" horned frogs and it would be really interesting to know how wide Beelzebufo was in life.

Sven wrote...

I was referring to the phrase "ceratophryid hyloid neobatrachian," which would seem to place it in both the family Ceratophryidae and the family Hyloidae

As should have been clear from the several Tet Zoo articles published on anurans last year (sorry if it wasn't, but having checked I think it was: go here or here), the two major neobatrachian clades are Hyloidea and Ranoidea, both traditionally imagined to be 'superfamilies'. So 'hyloid' refers to a 'superfamily', not a 'family'.

What Sordes calls "aga toad" is the cane toad, Rhinella marina, formerly Chaunus marinus, formerly Bufo marinus.

So is the -id suffix used for any old taxon, or does it still refer to a family, whatever that might mean?

There is no -id suffix in "hyloid". There's an -oid suffix. ;-Þ

By David Marjanović (not verified) on 21 Mar 2008 #permalink

Speaking of animal size, I should mention that Gerald Wood gives the maximum snout-vent length of the Cane toad as 238 mm, which makes 380 mm large to the point of being suspicious. That specimen weighed 1.3 kg and one 380 mm should weigh ~5.3 kg; Wikipedia gives the weight of the alleged specimen at 2.65 kg which could indicate somebody used linear scaling. Is this claim supported by any good evidence?

Wood did mention that the bullfrog record is normally 0.567 kg, but there was one outsized freak that allegedly weighed 3.289 kg. Apparently that weight is proportional to a ~90 cm total length, so either somebody got more clever than normal or amphibians can get freakishly outsized...

The 380 mm cane toad was Prinsen, a Swedish pet owned by Håkan Forsberg of Akers Styckebruk, apparently. But I took this information from Mark Carwardine's Guinness Book of Animal Records (the mass of 2.65 kg is given in there too), and as we saw in one of the caudate articles, not all of the facts therein are standing up. Incidentally, I asked Carwardine's agent about the poison-firing ability of the Painted ensatina, but have yet to hear back.

I have just spoken to Sue Evans about Beelzebufo and according to her team their estimate was a mass of 4-5 kg based on extant ceratophryid. I brought up the numbers from here of 10= kg and she said it was certainly possible but they felt unlikley.

By Dave Hone (not verified) on 25 Mar 2008 #permalink

Ah. Right. -Oid. OK.

By Sven DiMilo (not verified) on 30 Mar 2008 #permalink