The phylogenetic position of Isalorhynchus genovefae, a Late Triassic rhynchosaur from Madagascar
Abstract
New specimens of the rhynchosaur Isalorhynchus genovefae Buffetaut, 1983, have been found in the Makay Formation (Late Triassic of the Morondava Basin), Malio River area, southwest Madagascar. The material includes several maxillae as well as the first known rhynchosaur dentaries from the region. The maxilla bears a single longitudinal groove, with fewer than three longitudinal tooth rows both medial and lateral to it. The dentary possesses a single blade, with an additional row of teeth on its lingual surface. A phylogenetic study, based on the morphological features possible to measure for Isalorhynchus, as well as on previous cladistic analysis of Rhynchosauria, showed that the Malagasian rhynchosaur is nested within the genus Hyperodapedon, and a new combination - H. genovefae - is proposed. The phylogenetic study also depicts clear trends in the tooth evolution of Late Triassic rhynchosaurs, with the reduction of the medial structures in relation to the lateral ones, in both maxilla and dentary.
- Publication:
-
Annales de paléontologie
- Pub Date:
- 2000
- DOI:
- 10.1016/S0753-3969(00)80002-6
- Bibcode:
- 2000AnPal..86..101L