#goniopholidae

[arminreindl]

Ophiussasuchus: The Lourinhã Goniopholid

Not even a full three weeks into 2024 and we already have three new pseudosuchians, personally, I'm pretty satisfied with this developement.

The newest one is Ophiussasuchus  paimogonectes ("crocodile from Portugal that swims at Paimogo beach"), a goniopholid Neosuchian from the Late Jurassic Lourinhã Formation of Portugal.

Ophiussasuchus is known from a single specimen, but one thats quite complete, preserving almost the entirety of the skull in 3D and only missing a chunk of the right side of the end of the skull.

The skull of Ophiussasuchus is mesorostine and platyrostral. In simple terms, its of medium length and width and has a flattened skull. Platyrostry is pretty much the standard for goniopholids, but mesorostry is more noticable in that there are some other genera in the group with short snouts (like Nannosuchus) and long snouts (like Anteopthalmosuchus and Hulkepholis). Another more general feature of this animal is that it was a medium-sized member of its family, with estimates suggesting a length of somewhere between 2.5 to 3 meters.

As often the case, the devil lies in the detail. Ophiussasuchus is thought to have been most closely related to Hulkepholis and Anteophthalmosuchus, two goniopholids from the Early Cretaceous of Europe. However it displays several features that indicate an intermediate position. A nasopharyngeal duct is visible on the palate, but in its closest relatives the duct is enclosed and in the more basal American forms the duct is more open. Interestingly, the palate also features small palatal fenestrae, which are not seen in any other goniopholids aside from Siamosuchus. Interestingly, these two features are not just leftovers from its ancestry. Analysis suggest that the palate of the ancestor of Ophiussasuchus likely looked like that of the other European taxa, which in turn means that this anatomy was reversed in Ophiussasuchus. It's unclear if Ophiussasuchus simply lost that anatomy or if it actually converged with the more basal forms.

Anteophthalmosuchus and Hulkepholis, longirostrine relatives of Ophiussasuchus from the early Cretaceous. Figure from Arribas et al. 2019

Ophiussasuchus lived during the Late Jurassic (Kimmeridgian to Tithonian) in the Lourinhã Formation of Portugal. The Lourinha is perhaps most famous as "Europe's Morrison", sharing much fauna with its American counterpart. Just as an example both formations feature Allosaruus, Torvosaurus and some animals found in the Lourinhã Formation are at the very least related to American forms. Examples for the latter are Lusotitan and Brachiosaurus, Dinheirosaurus and Supersaurus as well as Miragaia and Alcovasaurus.

Goniopholids are also present in both formations, the Morrison featuring Amphicotylus, Eutretauranosuchus and Diplosaurus and Lourinhã being home to Ophiussasuchus.

Reconstruction below by Simão Mateus and Camilo Pineda

Obligatory wikipedia and paper links

Ophiussasuchus - Wikipedia

A new Portuguese goniopholidid (palaeo-electronica.org)