Taxonomy of the archosaur Ornithosuchus: reassessing Ornithosuchus woodwardi Newton 1894 and Dasygnathoides longidens (Huxley 1877)

BACZKO, M. B.; EZCURRA, M. D.

EARTH AND ENVIRONMENTAL SCIENCE TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH

ROYAL SOC EDINBURGH

Lugar: Edinburgo; Año: 2016

1755-6910

The pseudosuchian archosaur Ornithosuchus, from the Lossiemouth Sandstones Formation (LateTriassic), Scotland, was the first ornithosuchid to be discovered and the onlyone recorded in the northern hemisphere. The fossil record of ?Ornithosuchus longidens? is mainly basedon natural moulds and in a few cases by three-dimensional bony elements, thuscomplicating the interpretation of its anatomy. The taxonomy of this species sufferedseveral changes since the late 1800´s and in this contribution we revist itscurrent status. The synonymy of ?Dasygnathoideslongidens? and Ornithosuchuswoodwardi proposed by Walker (1964) is rejected based on the new interpretationof the hypodigm of ?Dasygnathoideslongidens?. This last species is here considered as a nomen dubium because of the lack of diagnostic features and cannotbe identified beyond Pseudosuchia. As a result we resurrect Ornithosuchus woodwardi as avalid species and we emendthe diagnosis of the species. The body size rangeof Ornithosuchus woodwardi is reducedto about its half because EM 1, which was previously considered the largestspecimen of the genus, is no longer regarded as cogeneric with Ornithosuchus. ?Dasygnathoides longidens? cannot be assigned to any of the known archosauriformsfrom the Lossiemouth Sandstones Formation, but nonetheless represents thelargest predator currently known from this unit.