More Beaks! – The Barber of Sevi–I Mean, Cuenca

Europejara olcadesorum, a new tapejarid pterosaur, has been described from the famous Las Hoyas lagerstät of Cuenca, Spain. This specimen is unique because, aside from the lagerstätten of Liaoning Province in China, tapejarids in the broad sense are known only from Gondwana.

Europejara alcadesorum

Skull and restoration of MCCM-LH 9413, holotype of Europejara olcadesorum (Vullo et al., 2012). Top, preserved cranial material from the slab, counterslab, and a combination with key. Bottom, restoration of the head, and the parts of the skull as from an intact skull (preserved material shown in red). Restoration by Oscar Sanisdro. Scale bars represent 50mm.

Tapejarids are weird. They have these enormously narrow yet high skulls, and tapejarines have shortened the whole affair while sporting tall premaxillary crests and deep dentary crests. In Europejara olcadesorum, the dentary crest is particularly deep, estimated at 4 times the depth of the median mandibular ramus depth; Tapejara wellnhoferi, the next closest pterosaur to this proportion, has a crest only 3 times the mandibular depth.

Found in the La Herguína Formation in the Las Hoyas lagerstätte in Cuenca, Spain, the holotype MCCM-LH 9413 represents the lower jaw and portions of the upper jaw, palate, and suspensorium (supporting the upper jaw articulation) of a relative small pterosaur, with a skull I’d estimate around 430mm long, or around 23inches. It is estimated to have a 2m wingspan. Despite the size of the head, this animal would not have been much larger than a house cat. Maybe a fat house cat. The jaw sports a deep sagittal crest on the ventral margin, as all tapejarine, tapejaroid (azhdarchoid, dsungaripteroid, what-have-you) pterosaurs have; the crest, however, is concave on its posterior margin, a feature unique to it. It is further autapomorphically characterized by having the dorsal margin of the mandible extend forward and, rather than rise into a crest as it does in Tupandactylus imperator, navigans or Tapejara wellnhoferi, curve downward towards the tip — a sigmoid rather than retroflexed curve (see above for comparisons).

This was enough to suggest to the authors, led by Dr. Romain Vullo of the Université de Rennes, and joined by pro-paleontologists Drs. Angela Buscalioni (Universidad Autónoma de Madrid) and Andrew Kellner (Universidade Federal do Rio de Janeiro and Museu de National), that they had something different. It only helped that this was the first time clear evidence of a tapejarid had been found in Europe, whereas other Lauriasian evidence had only come from north-eastern China. Even more so, the Las Hoyas lagerstätte is dated to Barremian of the Early Cretaceous, and thus predating or perhaps coinciding with the Jiufotang Formation of Liaoning Province, China, and the Santana Formation of Ceará State, Brasíl.

Thus, was born Europejara olcadesorum. “Europejara” is a portmanteau of “Europe” and “Tapejara,” while “olcadesorum” refers to the Olcades, an ethnic Iberian culture related to the Celtiberian group, whose capitol and range were largely located within Cuenca.

Partial phylogeny, mandibular morphology, and biostratigraphy of Europejara olcadesorum.

Partial phylogeny (I excluded non-azhdarchoid pterosaurs) with correlated mandibles of tapejarines, after Vullo et al. (2012). The geologic column to the right is mapped to the mandibles, with Europejara olcadesorum in orange, Sinopterus in light green (the fourth mandible represents Huaxiapterus jii, which was synonymized with Sinopterus as Sinopterux jii), and blue represents Tupandactylus imperator. Numbers in phylogeny represent (3) Azhdarchoidea and (4) Tapejarinae. Bars in the middle jaw illustrations represent scale bars of 50mm.

Tapejarines typically have relatively short skulls, given that they are nested within taxa having greatly elongated skulls. Rather, tapejarines are boxier, and their premaxilla rises from the rostral tip towards the vertical, resulting in a small crest anterior to the nasoantorbital fenestra. Depending in the phylogeny, tapejarines may be more basal to a group containing Azhdarchidae and Thalassodromeidae (and would be called Tapejaridae), and thus present the ancestral condition to the longer-skulled “azhdarchoid” morphology; or they are derived and the sister taxon to the Thalassodromeidae (now called Thalassodromeinae, within Tapejaridae — and if anything, a reason to just pick a name for each subset and stick to it, regardless of the arrangement of the particulars).

In the case of the former, tapejarines would present the basal condition, and other azhdarchoids elongated the skull uniquely from other pterodactyloid pterosaurs (all of whom have elongated skulls). Alternatively, depending on which derived first (and this does differ from one analysis to the other), all taxa started off elongated and became progressively shorter, and only Tapejara wellnhoferi and the Tupandactylus complex of species became “boxy” and vertical crested.

In the case of the latter — as represented in the phylogeny shown above — the boxy skull appears to predate the elongated skull of a “sinopterine” radiation, so that regardless of Tapejara wellnhoferi‘s peculiarness, tapejarines underwent a “boxy” phase, then reverted to the basal thalassodromeid condition of azhdarchoids. Europejara olcadesorum represents a moderately elongated mandible, between Tupandactylus and Tapejara, but the ventral sagittal crest of the dentary is extremely developed, giving it the impression of high derivation from the Tapejara condition. Whichever pattern resolves, it seems that tapejarines (okay, tapejarids) were playing around with the shape of the jaw, which can be expected if they were exploiting new diets or in competition with different groups of carnivores. It should also be considered that the cranial variation, including the development of the mandibular sagittal crest, may represent aerodynamic maneuvering stabilizers (Kellner & Campos, 2002, Chatterjee & Templin, 2004; but see Humphries et al., 2007 and Witton & Naish, 2008 for contradictory evidence) or mutual sexual selection rather than dietary (see Hone et al., 2012 and Darren Naish’s discussion of that paper for more information).

Whatever the reasons, selection appears to have favored the elongated skull, and purported a shorter skull rarely, but more elaborate headgear more frequently. The function of the odd mandibular sagittal crest may be a topic I will return to later.

[n1] Okay, so the title is somewhat of a pune (or play on words). Here, it’s a reference to the word barbus “bearded” as a reference to the strapping chin on that new pterosaur, and of course playing with the title The Barber of Seville, which occurs in Spain. Well, so does Cuenca. I’m leaving this note to explain the title because I’m a little OCD on the matter: I don’t like obscure jokes only a few people will get.

Chatterjee, S. & Templin, R. J. 2004. Posture, locomotion, and paleoecology of pterosaurs. Geological Society of America, Special Paper 376:1-64.
Hone, D. W. E., Naish, D. & Cuthill, I. C. 2012. Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs? Lethaia 45(2):139-156.
Humphries, S., Bosner, R. H. C., Witton, M. P. & Martill, D. M. 2007. Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method. PLoS Biology 5(8):e204.
Kellner, A. W. A. & de Campos, D. A. 2002. The function of the cranial crest and jaw of a unique pterosaur from the Early Cretaceous of Brazil. Science 297:389-392.
Sanz, J. L., Fregenal-Martínez, M. A., Meléndez, N. & Ortega, F. 2001. Las Hoyas. pp.356-359 in Briggs, Crowther & Crowther (eds.) Palaeobiology II. Wiley-Blackwell.
Vullo, R., Marugán-Lobón, Kellner, A. W. A., Buscalioni, A. D., Gomez, B., de la Fuente, M. & Moratalla, J. J. 2012. A new crested pterosaur from the Early Cretaceous of Spain: The first European tapejarid (Pterodactyloidea: Azhdarchoidea). PLoS ONE 7(7):e38900.
Witton, M. D. & Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE 3(5):e2271.

About these ads
This entry was posted in Paleontology, Science Reporting and tagged . Bookmark the permalink.

3 Responses to More Beaks! – The Barber of Sevi–I Mean, Cuenca

  1. Nick G. says:

    Only 6 more steps to get neoazhdarchian thalassodromids in their tree. The next question is whether Vullo et al. sampled characters that Andres et al. used to support the alternative position for thalassodromids.

    • Nick G. says:

      *using their matrix, rather. Bad habit.

    • Well, I’m going to assume that neither of the two trees should be considered the “accurate” tree. Neither is as comprehensive as some of the dinosaur trees we’ve been seeing, and that’s a shame because there’s just as much variation going on with Pterosaurs, if not more (selective competition and all that).

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s