Friday, November 25, 2011

Scarfe's snout

This is a shameless re-post from the Musings, but really rather an appropriate one. Not only is it about a brand new pterosaur from the UK, but the post (and indeed new pterosaur) come courtesy of Dave Martill. Dave supervised the PhD research of Lorna steel, Darren Naish and Mark Witton, so in one way he has quite a claim to Take it away Dave:

Cuspicephalus scarfi from the Late Jurassic Kimmeridge Clay Formation of Dorset is one of those irritating fossils. It was clearly a beautiful animal, with long, slender jaws and fine teeth that would have made it look impressive. It is without doubt a cracking fossil, displaying a near perfect right lateral outline, with only a little bit of the dorsal rest missing. OK, it is sad that the lower jaw and rest of skeleton is missing, but in the UK, this specimen is the best thing since the second specimen of Dimorphodon was discovered in the Lower Jurassic in the mid 1800s. But despite its near completeness for a British pterosaur skull, it is not entirely clear where it belongs in the grand scheme (or schemes), of pterosaur phylogeny. It appears to be a pterodactyloid similar to Germanodactylus on the basis of its single NAOF and straight dorsal border, but when compared with Darwinopterus, its affinities become less clear cut. Sure, it isn’t Darwinopterus, but it isn’t Germanodactylus in the strictest sense either. Dave Unwin thinks it might lie close to the base of Dsungaripteroidea, and I am inclined to agree, but caution that this is based mainly on the nature of its crest… not a good criterion given the distribution of elongate fibrous-looking crests in Pterosauria.

[caption id="attachment_6550" align="aligncenter" width="500" caption="Cuspicephalus skull. From Martill & Etches, in press"][/caption]

Cuspicephalus was discovered by Steve Etches. Known to most UK vertebrate palaeontologists, Steve collects fossils exclusively from the Kimmeridge Clay of Dorset and has built up a renowned collection housed in the Museum of Jurassic Marine Life (MJML) in Kimmeridge, Dorset. Steve discovered Cuspi on the wave cut platform in Kimmerdge Bay and reckons that one more tide would have destroyed it. Steve has found several other pterosaurs in the Kimmeridge Clay, some of which are represented by associated remains attributable to an animal close to Rhamphorhynhcus, and currently being examined by PhD student Michael O’Sullivan. A few specimens in Steve’s MJML have been identified as representing a germanodactylid by DMU, and it is possible that these elements are from the same animal as Cuspicephalus: clearly Steve needs to get out and find the complete skeleton.
The name Cuspicephalus is derived from the sharp pointed nature of the skull in lateral view, and I suspect in dorsal view too, but Kimmeridge Clay fossils are rather 2D to tell. The specific epithet honours Gerald Scarfe CBE. Scarfe is known to most UK citizens as the artist who provided the caricatures for the intro to the extremely popular satirical TV series Yes Minister and follow up Yes Prime Minister. Both were excellent lampoons of the UKs higher civil servants and mainly incompetent elected politicians. Globally Scarfe is known to several generations of Pink Floyd fans as the artist behind The Wall (album, film and more).

[caption id="attachment_6549" align="alignright" width="226" caption="Margret Thatcher as drawn by Gerald Scarfe. Courtesy Dave Martill"][/caption]

To readers of certain newspapers and periodicals Scarfe is loved or laothed for hard hitting political caricatures, and in particular those of British Prime Ministers and other notorious world leaders. Many were reproducible in daily newspapers, but others remained within the underground literature for reasons of decency (check out Rupert bear ****ing Mary Whitehosue with the Pope watching on). One cartoon of Scarfe’s that stands out is a caricature of Margaret Thatcher, an ex British Prime Minister who Scarfe Portrayed as a Tory blue, saggy-breasted pterodactyle, and therefore it seemed only fair that he should be honoured. Scarfe’s cartoon might have the number of fingers wrong, and he might have followed the Frey and Riess model for the orientation of the pteroid, but we all know he got the colour right.

Pip pip

Monday, November 21, 2011

Water Launching Pterosaurs

This post is a cross-post from H2VP (again), but should be of interest to readers.

I gave two presentations at SVP this year, and the second (in the form of a poster) was on pterosaur water launch. Specifically, I presented a model that Jim Cunningham and I have worked out for a plausible water launch strategy in Anhanguera. If you want to see what this might have looked like, turn your cursors here to Mark Witton's website. The relevant illustration is on the far right.

I will not give too much detail on this presentation at the moment, as it is shortly bound for PLoS ONE. However, here are some of the highlights:

- A bipedal water launch model appears to fail for Anhanguera (and other pterosaurs), just as the bipedal model fails for their terrestrial launch.

- A quadrupedal water launch model, in which the wings are the primary mechanism used to free the animal from the surface and to push along the surface to reach launch velocity, seems to check out for all of the parameters we can currently estimate with any confidence.

- Anhanguerids probably took multiple hops across the water surface to launch, but our calculations suggest that most of the actual energy expenditure was spent escaping the surface tension.

- Our model makes testable predictions about comparative anatomy of pterosaurs, which is important when building these kinds of models from fluid theory. Our model predicts that water launching pterosaurs should have features such as: warped deltopectoral crests or dp crests with flared distal ends, enlarged scapulae, extreme disparity between forelimb and hindlimb lengths, and reinforced scapulo-notarial joints. We have a more extensive list of features that can be shared a later date, but the primary note here is that these predicted features do indeed seem to show up mostly in marine pterosaurs, and less so in terrestrial taxa, so there is a least a loose, pattern-matching form of validation that can be applied to our hypothesis.

We hope to have animations and a full paper out on the topic of pterosaur water launch in the near future (next few months) so stay tuned!

Wednesday, November 2, 2011

Aurorazhdarcho - a Jurassic azhdarchoid

Just a short post on this little fellow. I don't generally like blogging on new taxa as a lot of other people cover them and there's generally not much that can be said from an outside perspective that's not in the paper. I don't have much to add in that respect here either, but this is a nice thing for me to see out as I've seen the specimen knocking around in Dino Frey's office on a number of occasions over the last few years while being assured it would be described 'soon'. Well, now it is out and Aurorazhdarcho is born.

The specimen is obviously in superb condition (photos above and below lifted from Frey et al., 2011) though the head and neck are gone. Still, an impression remains on the sediment to show where they originally lay and given an idea of their original size and shape which is rather nice.

The most interesting thing though is the identification of this as member of the azhdarchoids. This most derived of pterosaur clades are otherwise known only from the Cretaceous, though a Jurassic origin is to be expected if (and for some, this is a big if) you accept that Germanodactylus is a dsungariptid and that this clade is the sister-taxon to the azhdarchoids. Certainly it has a few features that are unique to the group (that huge hindlimb for starters) and this identification looks good to me (though I have to confess I have yet to read the paper in full detail), though as ever with a specimen like this, the lack of a head is a real shame.

Frey, E., Meyer, C.A. & Tischlinger, H. 2011. The oldest azhdarchoid pterosaur from the Late Jurassic Solnhofen Limestone (Early Tithonian) of Southern Germany. Swiss Journal of Geosciences in press.