G. Lio1, R.
Juarez Valieri2, L. S. Filippi3 and F. L. Agnolín1,4
The clade Peirosauridae is mainly a Gondwanan
group composed by mid to large sized terrestrial crocodyliforms. The peirosaurid
here reported comes from the upper levels of the Portezuelo Formation (Turonian-Coniacian,
Upper Cretaceous) at Añelofossiliferous locality, Neuquén Province, Argentina.
This specimen consists on an incomplete skeleton composed by a left dentary and
splenial, right maxilla, right jugal, a dorsal vertebra, a dorsal osteoderm,
and right humerus. Its referral to Peirosaurideae is sustained by: posterior
maxillary teeth low and globular, with a clear neck and serrated carinae,
festooned maxillary and dentary ornamentation, and the presence of amphicoelous
vertebral centra with large hypapophyses. The new specimen is related to Gasparinisuchusin having mandibular
symphysis extending posteriorly to the level of eight tooth and with a large
participation of the splenials. Anyhow some differences may be observed: in the
new specimen the maxillary teeth are not separated in discrete alveoli, the
dentary symphysis is very elongate and compressed and surpasses the level of
the ninth tooth, the fourth dentary tooth is caniniform, very large, acute and
transversely compressed (much larger than other peirosaurids), and the anterior
dentary teeth exhibit less globular, and sharp serrated crowns. This suggests that
the specimen here reported had greater heterodont dentition when compared with
remaining taxa. With this addition, we elevate to four the number of Patagonian
peirosaurids, increasing the diversity for the clade in this landmass.
Moreover, it represents the only peirosaurid described for the Portezuelo
1Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, Buenos Aires, Argentina.
2 Secretaría de Cultura de la Provincia de Río Negro,8332 General Roca, Río Negro, Argentina.
3 Museo Municipal Argentino Urquiza. Jujuy y Chaco s/n, 8319, Rincón de los Sauces, Neuquén, Argentina.
4Fundación de Historia Natural “Félix de Azara”, Universidad Maimónides, Hidalgo 775, Buenos Aires, Argentina
Resumenes XXVIII Jornadas Argentinas de Paleontología de Vertebrados, Zapala-Chocón, Neuquén, Argentina. 21 al 23 de Mayo del 2014.