Anteophthalmosuchus


Anteophthalmosuchus is an extinct genus of goniopholidid neosuchian from the Early Cretaceous of southern England, eastern Spain, and western Belgium. It measured around in length, and had a skull length of about.

Discovery

The holotype specimen of Anteophthalmosuchus, from the Wealden Group of the Isle of Wight, includes a well-preserved skull and partial skeleton. This specimen has been known since 1904 and was identified as the "Tie Pits specimen" or the "Hooley specimen" after Reginald Walter Hooley, an amateur paleontologist who had described it in 1905. Hooley had originally attributed the specimen to the previously named species Goniopholis crassidens. Additional referred specimens include a partial disarticulated skeleton and a partial skull that may represent a juvenile specimen.
In 2011, Hooley's specimen was redescribed as a distinct genus and species of goniopholidid called Anteophthalmosuchus hooleyi. The genus name means "forward-pointing eye crocodile" because the specimen's eye sockets are positioned high on the skull and angle forward rather than to the side as in most other flat-skulled crocodyliforms, and the species name honors Hooley. Features that distinguish A. hooleyi from Goniopholis crassidens include the lack of a hole in the lower jaw called the mandibular fenestra, very wide supratemporal fenestrae on the skull table, and a bone above the eye socket called the palpebral that is small and does not extend over the socket as in some other goniopholidids.

Two specimens from Bernissart, Belgium, collectively referred to as "Dollo's goniopholidid", was referred to A. hooleyi in a 2016 redescription. The specimens, which consist of complete skeletons from the Sainte-Barbe Clays Formation, were originally referred to Goniopholis simus by Dollo. In 2016, they were recognized as specimens of A. hooleyi due to their distinctive eye sockets, among other defining characteristics of the species. While the Dollo specimens do not possess frontal bones that are pointed at the rostral end, a trait in 2011 to establish A. hooleyi as a distinct species, and also differs in the relative proportions of the occipital condyle and foramen magnum, the authors considered these traits invalid diagnostic characteristics, as they could be a consequence of age differences or preservational artifacts. However, in 2017, Dollo's goniopholidid was moved to a new species, Anteophthalmosuchus epikrator, based on comparisons with newly-discovered specimens from the Isle of Wight.
A second species, Anteophthalmosuchus escuchae, was first described and named by A.D. Buscalioni, L. Alcalá, E. Espílez and L. Mampel in 2013. It is known solely from the holotype AR-1-1097 which consists of a partial skull. It was collected from the early Albian-aged Escucha Formation, at Santa Maria Mine located in the municipality of Ariño, Teruel Province, of Aragon, along with the closely related Hulkepholis plotos.

Description

Estimated at in length, Anteophthalmosuchus would have been the largest crocodyliform in the Wealden faunal assemblage, larger than the contemporaneous species Hylaeochampsa vectiana, Leiokarinosuchus brookensis, and Vectisuchus leptognathus.

Skull

Anteophthalmosuchus' skull, when complete, would have measured around in length. The majority of the skull, including the maxillary portion of the snout and most of the infratemporal part of the skull, was covered in regularly spaced, circular pits, as in Goniopholis. The palpebral bone was very small and did not project laterally over the orbit, unlike in other goniopholidids. The supratemporal fenestra was subcircular, and at its widest was almost twice the diameter of the orbits. The occipital condyle was roughly ten percent of the maximum width of the dorsal portion of the skull. Unlike Goniopholis crassidens, but like G. baryglyphaeus, A. hooleyi lacked an external mandibular fenestra.

Phylogeny

Anteophthalmosuchus hooleyi was included in a phylogenetic analysis of goniopholidids that was published soon before the specimen was redescribed. The Hooley and Dollo specimens were found to be the closest relatives of a specimen called "Hulke's goniopholidid", now named Hulkepholis willetti. Below is a cladogram from that analysis: