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"Steneosaurus barettoni" (metriorhynchid crocodylomorph material) redescribed



From: Ben Creisler
bcreisler@gmail.com

A new online paper:


Andrea Cau (2013)
The affinities of ‘Steneosaurus barettoni’ (Crocodylomorpha,
Thalattosuchia), from the Jurassic of Northern Italy, and implications
for cranial evolution among geosaurine metriorhynchids.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2013.784906
http://www.tandfonline.com/doi/full/10.1080/08912963.2013.784906

In 1787, a fragmentary fossil skull of a crocodylian was discovered in
the Altopiano dei Sette Comuni (Veneto, Northern Italy). In 1883, the
specimen was referred to a new species of the teleosauroid
Steneosaurus, S. barettoni. In this study, the specimen is redescribed
and its taxonomic status reviewed. S. barettoni fails to conform to
Article 12 of the International Code of Zoological Nomenclature and is
considered as a nomen nudum. The specimen lacks synapomorphies of both
Teleosauroidea and Steneosaurus, whereas it is referred to
Metriorhynchidae based on the presence of an elongate median
depression between the dorsal surface of nasals, and a large
teardrop-shaped prefrontal that is expanded laterally. The combination
of cranial and dental features present in this specimen supports its
referral to Neptunidraco, an interpretation that adds new information
on the morphology of the Italian metriorhynchid. Although total
evidence analysis placed Neptunidraco as a basal divergence among
Geosaurinae, it independently evolved some craniomandibular features
previously considered exclusive of the macrophagous Geosaurini. This
specimen is historically relevant because it may represent the first
metriorhynchoid found worldwide.