El placodonto Parahenodus atancensis en el XVI Annual Meeting de la EAVP

Ya estáis viendo estos días lo mucho que ha dado de sí para el GBE el último Encuentro de la EAVP, celebrado en Caparica (Portugal). Hoy le toca el turno al recientemente descrito placodonto Parahenodus atancensis, cuyo estudio fue presentado en formato póster en el congreso. 

Sin más dilación, aquí va el abstract:

Henodus chelyops, from the Carnian (Upper Triassic) of Tübingen (Germany), is a highly derived cyamodontoid placodont, showing an extremely modified skull compared with other representatives of Cyamodontoidea. Based on this, trophic adaptations very different from those of other placodonts have been proposed. Whereas the other taxa are durophagous animals, herbivory and filter feeding has been suggested for H. chelyops. The phylogenetic position of this taxon within Cyamodontoidea could not be, until now, well established.

We present a partial skull of a cyamodontoid recently found in El Atance fossil site (Upper Triassic, Guadalajara, Spain), MUPA-ATZ0104. MUPA-ATZ0104 corresponds to a new taxon. Its inclusion in a cladistic analysis shows it is the sister taxon of H. chelyops. Both taxa are identified as members of the clade Henodontidae, hitherto considered as monotypic. Several character states previously recognized as exclusive of H. chelyops are synapomorphies of Henodontidae, including: maxillae without teeth; a single palatine tooth; upper temporal fenestrae reduced to absent; broad parietals; palatines separated by pterygoids. Based on this information, the diagnosis of Henodontidae is emended. This clade is recognized as belonging to Cyamodontida.

In addition to the presence of several character states hitherto considered as autapomorphies of H. chelyops, MUPA-ATZ0104 shares other character states with some less derived cyamodontoid placodonts, including: skull narrowed anteriorly; upper temporal fossae opened; larger palatine teeth. The discovery of this new form provides important information on both the acquisition of the highly specialized cranial morphology of H. chelyops and the evolutionary history of the clade Henodontidae. 
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