New information on the skull of Patagonykus puertai (Theropoda, Alvarezsauridae)

MESO, JORGE; BAIANO, MATTIA; CANALE, JUAN IGNACIO; CORIA, RODOLFO; SALGADO LEONARDO

Corrientes

Jornada; XXXII Jornadas Argentinas de Paleontología de Vertebrados; 2018

The small coelurosaur theropod Patagonykus puertai (PVPH-37), recovered in Portezuelo Formation (Turonian?Coniacian, Upper Cretaceous), from Neuquén province, Argentina, was originally published as represented by postcranial elements of a single individual. A recent review of the holotype specimen has revealed the presence of several cranial remains that include: both frontals articulated and attached to the right prefrontal, a possible fragment of the right nasal, a fragment of the left squamosal articulated with a distal fragment of the postorbital, and a fragment of the left dentary. Frontals are longer than wide, with a simple interfrontal suture, lacking the complex interdigitation observed in Shuvuuia. In the anterior end, the frontal shows a short and transversal contact with the nasal, similar to the condition present in Haplocheirus. Anterolaterally, the frontal has a long contact with the prefrontal, as observed in Shuvuuia. The squamosal is triangular, pre- sumably with the plane facing dorsolaterally and ventromedially as in Shuvuuia. The anterior projection is compressed anteromedially to dorsolaterally, and contacts the postorbital through a sigmoid suture. Anteroventrally, the quadratojugal process is short and robust resembling Shuvuuia, but dorsoventrally flat as in Haplocheirus. The dentary is dorsoventrally low and lateromedially wide, as in Haplocheirus. The new cranial information could improve the internal phylogenetic relationships of the clade, especially between the Patagonykinae and the other internal taxa of Alvarezsauridae.