Anteophthalmosuchus

Anteophthalmosuchus (meaning "forward-pointing eye crocodile") is an extinct genus of goniopholidid mesoeucrocodylian from the Early Cretaceous of southern England, eastern Spain,[1][2][3] and western Belgium.[4]

Anteophthalmosuchus Temporal range: Early Cretaceous, Barremian–Aptian PreꞒ Ꞓ O S D C P T J K Pg N
A. epikrator ("Dollo’s goniopholidid", specimen IRSNB R47), Musee d'Histoire Naturelle, Brussels
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Family:	†Goniopholididae
Genus:	†Anteophthalmosuchus Salisbury & Naish, 2011
Type species
†Anteophthalmosuchus hooleyi Salisbury & Naish, 2011
Other species
†A. escuchae Buscalioni et al., 2013 †A. epikrator Ristevski et al., 2017
Synonyms
Leiokarinosuchus brookensis Salisbury & Naish, 2011

Discovery

Fossils from the Wessex Formation along a skull replica

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.[5][4]

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 (openings) 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.[5]

A. epikrator skull

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 (one missing the skull) 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.[4] 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.[6]

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.[3]

Description

At an estimated 4 metres (13 ft) in length, A. hooleyi would have been the largest crocodyliform in the Wealden faunal assemblage, larger than the contemporaneous species Hylaeochampsa vectiana, Leiokarinosuchus brookensis, and Vectisuchus leptognathus.[5]

Phylogeny

Illustration of "Dollo’s goniopholidid", 1882

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:[7]

Neosuchia

Atoposauridae   Theriosuchus pusillus     Theriosuchus guimarotae           Rugosuchus       Bernissartia     Eusuchia           Stolokrosuchus         Tethysuchia     Thalattosuchia     Goniopholididae   Calsoyasuchus valliceps         "Goniopholis" phuwiangensis       Eutretauranosuchus delfi     "Sunosuchus" junggarensis         Sunosuchus miaoi     Sunosuchus thailandicus           Siamosuchus phuphokensis       Amphicotylus lucasii       Denazinosuchus kirtlandicus     Nannosuchus gracilidens         Hulkepholis (Hulke's goniopholidid)       Anteophthalmosuchus (Hooley’s goniopholidid)     Anteophthalmosuchus (Dollo’s goniopholidid)       Goniopholis   Goniopholis baryglyphaeus       Goniopholis kiplingi     Goniopholis simus

References

1. Steven W. Salisbury; Darren Naish (2011). "Crocodilians". In Batten, D. J. (ed.). English Wealden Fossils. The Palaeontological Association (London). pp. 305–369.
2. Naish, Darren (2 December 2011). "The Wealden Bible: English Wealden Fossils, 2011". Tetrapod Zoology. Scientific American Blogs. Retrieved 5 December 2011.
3. Buscalioni, A.D.; Alcalá, L.; Espílez, E.; Mampel, L. (2013). "European Goniopholididae from the Early Albian Escucha Formation in Ariño (Teruel, Aragón, España)". Spanish Journal of Palaeontology. 28 (1): 103–122.
4. Martin, J.E.; Delfino, M.; Smith, T. (2016). "Osteology and affinities of Dollo's goniopholidid (Mesoeucrocodylia) from the Early Cretaceous of Bernissart, Belgium". Journal of Vertebrate Paleontology. 36 (6): e1222534. doi:10.1080/02724634.2016.1222534.
5. Naish, Darren (24 September 2012). "In pursuit of Early Cretaceous crocodyliforms in southern England: ode to Goniopholididae". Tetrapod Zoology. Scientific American Blogs. Retrieved 24 September 2012.
6. Ristevski, J.; Young, M.T.; de Andrade, M.B.; Hastings, A.K. (2017). "A new species of Anteophthalmosuchus (Crocodylomorpha, Goniopholididae) from the Lower Cretaceous of the Isle of Wight, United Kingdom, and a review of the genus". Cretaceous Research. 84: 340–383. doi:10.1016/j.cretres.2017.11.008.
7. De Andrade, M. B.; Edmonds, R.; Benton, M. J.; Schouten, R. (2011). "A new Berriasian species of Goniopholis (Mesoeucrocodylia, Neosuchia) from England, and a review of the genus". Zoological Journal of the Linnean Society. 163: S66–S108. doi:10.1111/j.1096-3642.2011.00709.x.