Ultrastenos

Ultrastenos Temporal range: Late Oligocene, 28.1–23 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Clade:	†Mekosuchinae
Genus:	†Ultrastenos Stein et al., 2016
Type species
Ultrastenos willisi Stein et al., 2016 (Junior synonym)
Species
U. huberi (Willis, 1997)
Synonyms
Baru huberi Willis, 1997 Ultrastenos willisi

Ultrastenos is an extinct genus of Australian mekosuchine crocodilian that lived during the Late Oligocene in northwestern Queensland, Australia. Following its discovery, it was speculated that Ultrastenos was a slender-snouted animal similar to modern gharials or freshwater crocodiles due to the seemingly abruptly narrowing mandible. However, a later study found that this was a missinterpretation of the fossil specimen and that Ultrastenos instead had a more generalized lower jaw. The same publication also provided evidence that the fossils of Ultrastenos belonged to the same animal previously named "Baru" huberi, adding further evidence to the idea that the animal was short snouted, contrary to the initial hypothesis. Given that "Baru" huberi was named first, the type species of Ultrastenos changed from U. willisi to U. huberi in accordance with the rules of the ICZN. Ultrastenos was a small mekosuchine, measuring upwards of 1.5 m (4 ft 11 in) long.