2001. Journal of Vertebrate Paleontology, Abstracts of Papers, 21(3):91.

RASMUSSON, Erin L., Michigan St. Univ. Mus., East Lansing, MI 48823; BUCKLEY, Gregory A., ETSUC, Roosevelt University, Chicago, IL 60605.

Trematochampsids are poorly known crocodyliforms found in the Cretaceous of Africa, South America, Madagascar, and possibly the Cretaceous and Tertiary of Europe. Material described to date primarily consists of fragmentary cranial and mandibular remains. Among the taxa included in this group is Trematochampsa oblita, originally described from the Late Cretaceous of Madagascar solely on the basis of a partial dentary. Recent fieldwork in the upper part of the Maevarano Formation (Late Cretaceous) of the Mahajanga Basin, NW Madagascar, has produced additional material of T. oblita that adds to our knowledge of this species. The new material includes a more complete dentary, along with a frontal, parietal, and other associated cranial elements. The new dentary has an intact anterior end, not present in the holotype, which shows the size of the first alveolus and the elongate nature of the mandibular symphysis. There are twelve alveoli present in the preserved portion of the dentary, with the first, fourth, and tenth being the largest. The seventh alveolus is much smaller to allow for an embayment to accommodate a large maxillary tooth. The fourth alveolus is elevated above the level of the others. The lateral surface of the dentary is heavily sculpted with prominent pits and grooves.

The trematochampsids are poorly known and their monophyly has been questioned. The new material of T. oblita allows for more meaningful systematic comparisons with other taxa assigned to this group. In addition, the new T. oblita material was recovered from a different horizon than the several other Maevarano Formation crocodilians, suggesting possible resource or habitat partitioning among these Late Cretaceous forms.