Iharkutosuchus is very cool (and unusual). Three papers have been published on it, but it's a complete no-blip on the blogosphere radar. So I thought I'd take the time to post some information and images of this awesome eusuchian.




Figure 1 from Osi (2008)- Iharkutosuchus paratype, A-B skull in dorsal view; C-D skull in ventral view

Iharkutosuchus has a low, short, and moderately broad skull. Osi et al. (2007) ran a modified version of the matrix from Buscalioni et al (2001- Allodaposuchus). Their results show that Iharkutosuchus is a hylaeochampsid (Osi et al. 2007) based on the presence of a straight suture between the frontal and parietal, the prefrontal is longer than lacrimal, the pterygoid flanges are relatively small, and there is a vertical ridge on the occipital surface of the paroccipital process just lateral to the distal end. Osi et al. also ran a constraint based on molecular-morphological topologies from Gatesy et al. 2003, which resulted in Allodaposuchus being a hylaeochampsid. These taxa are close in other published trees (e.g. Pol et al. 2009). Only time (i.e. better fossils, better datasets) will tell.

Iharkutosuchus shows heterodonty (e.g. from anterior to posterior, the teeth transition from incisiviform to premolariform to molariform) and multicusped teeth, as well as tooth wear that seems to indicate that the mandible may have had some mediolateral movement while biting. Many other heterodont crocodyliforms do not have incisiviform anterior teeth, instead they are mostly conical (except being Simosuchus with its weird pseudo-ankylosaur teeth). Osi et al. regarded Iharkutosuchus as herbivorous, feeding on tough fibrous plants. Osi and Weishampel (2009) took this even further, presenting a detailed description of the microwear and mandibular mechanics.



Figure 9 from Osi (2008) - Reconstruction of Iharkutosuchus skull in A- ventral, B- dorsal, C- left lateral views, mandibles D- left in lateral view, E- both in dorsal view

Incidentally, Iharkutosuchus comes from the same formation as Hungarosaurus (a nodosaurid ankylosaur). Osi (2004) noted the presence of rhabdodontid and theropod teeth here as well. Polyglyphanodontine teiids (e.g. Bicuspidon were also crawling around here too. Azhdarchid pterosaur fragments have also been recovered here. Hopefully, this is enough to get some paleoartists interested in some scenes ;)

References on Iharkutosuchus

• Osi, A. 2008. Cranial osteology of Iharkutosuchus makadii, a Late Cretaceous basal eusuchian crocodyliform from Hungary. N. Jb. Geol. Paläont. Abh., 248: 279-299.
• Osi, A., Clark, J. M., and Weishampel, D. B. 2007. First report of a new basal eusuchian crocodyliform with multicusped teeth from the Upper Cretaceous (Santonian) of Hungary. N. Jb. Geol. Paläont. Abh. 243: 169-177.
• Osi, A. and Weishampel, D. B. 2009. Jaw mechanism and dental function in the Late Cretaceous Basal Eusuchian Iharkutosuchus. J. Morph., online doi: 10.1002/jmor.10726

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