Yvridiosuchus

Yvridiosuchus (meaning "hybrid crocodile") is an extinct genus of machimosaurid crocodyliform from the Middle Jurassic (Bathonian) Cornbrash Formation of England and the Sommet de la Grande Oolithe, Calvados, France.

Yvridiosuchus Temporal range: Middle Jurassic Bathonian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Holotype of 'Y. boutilieri and referred specimen (holotype of "S." meretrix)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Suborder:	†Thalattosuchia
Family:	†Machimosauridae
Tribe:	†Machimosaurini
Genus:	†Yvridiosuchus Johnson et al., 2019
Species:	†Y. boutilieri
Binomial name
†Yvridiosuchus boutilieri (Eudes-Deslongchamps, 1868)
Synonyms
Steneosaurus boutilieri Eudes-Deslongchamps, 1868 Teleosaurus brevidens Philips, 1871 "Steneosaurus" meretrix Phizackerley, 1951

History

Four skulls assigned to Yvridiosuchus at the OUMNH; a skull assigned to Y. boutilieri (A), the holotype skull of "Steneosaurus" meretrix (B), a jaw assigned to Y. boutilieri (C) and the holotype skull of Y. boutilieri (D)

The type species was originally named in 1868 as the species Steneosaurus boutilieri. The genus Steneosaurus was used as a longtime wastebasket taxon for various teleosauroid specimens and had more than a dozen species. The type species, Steneosaurus rostromajor is undiagnostic, making the genus and species dubious and invalid. Additionally, many species of so called species of "Steneosaurus" were found to be quite different and unrelated to one another, thus needing new generic names.^[1]

In 2019, Michela Johnson and colleagues redescribed "Steneosaurus" boutillieri, creating the new genus and combination Yvridiosuchus boutilieri. It's name references its combination of traits seen in both more basal and more derived machimosaurids. They also found the species "Steneosaurus" meretrix

Classification

Yvridiosuchus is the oldest known member of Machimosaurini, a clade of large, predatory machimosaurids with powerful jaws and teeth. Yvridiosuchus was named on the basis that it has characteristics of both earlier machimosaurids and the derived machimosaurins, such as conical, blunt teeth.

The cladogram below is from an analysis by Johnson and colleagues in 2020. ^[1]

Machimosauridae	Macrospondylus bollensis Clovesuurdameredeor stephani Charitomenosuchus leedsi Seldsienean megistorhynchus Deslongchampsina larteti Machimosaurinae Proexochokefalos hebertii cf. Proexochokefalos bouchardi Neosteneosaurus edwardsi Andrianavoay baroni Machimosaurini Lemmysuchus obtusidens Yvridiosuchus boutilieri Machimosaurus buffetauti Machimosaurus mosae Machimosaurus rex Machimosaurus hugii

Ecology

Yvridiosuchus had large and powerful jaws, with very large muscle attachment sites. Additonally, this species possessed both conical and blunt dentition. All of this suggests that it was well adapted for feeding on large and armored prey items such as turtles and large fish.^[2]

It co-existed with the more generalist machimosaurid Deslongchampsina, showing how multpiple machimosaurids could coexist by focusing on different types of prey.^[3]