Revision of Sulcusuchus erraini (Sauropterygia, Polycotylidae) from the Upper Cretaceous of Patagonia, Argentina

O'GORMAN, J.P; GASPARINI, Z

ALCHERINGA

TAYLOR & FRANCIS LTD

Año: 2012

0311-5518

Sulcusuchus erraini, from the upper Campanian?lower Maastrichtian of Patagonia, Argentina, is the only polycotylid from the Southern Hemisphere for which the skull and mandible are known. The diagnosis of the species and genus is emended based on new observations. The genus Sulcusuchus characterized by the following autapomorphies: (1) deep and broad rostral and mandibular grooves and (2) a wide notch on the posterior margin of the pterygoids that are combined with a part of the body of the basioccipital, forming a wide plate. Several hypotheses about the identity of the structures which could have been housed in the rostral and mandibular grooves are evaluated. Onli two of several hypothesis were not discarted. The fist one is that the grooves may have been related to oral glands (supralabial and sublabial) but the biological role of these glands could not be inferred. The second hypothesis is the presence of special sensitive structures, of an electrosensitive and/or a mechanosensitive type, which can allow the detection of infaunal or semi-infaunal food in soft bottoms, as it is seen in modern analogues, such as dolphins.