Hovasaurus boulei, an aquatic eosuchian from the Upper Permian of Madagascar
Date
1981
Authors
Currie, P. J.
Journal Title
Journal ISSN
Volume Title
Publisher
Bernard Price Institute for Palaeontological Research
Abstract
Hovasaurus is the most specialized of four known genera of tangasaurid eosuchians, and is
the most common vertebrate recovered from the Lower Sakamena Formation (Upper Permian,
Dzulfian Standard Stage) of Madagascar. The tail is more than double the snout-vent
length, and would have been used as a powerful swimming appendage. Ribs are pachyostotic
in large animals. The pectoral girdle is low, but massively developed ventrally. The front limb
would have been used for swimming and for direction control when swimming. Copious
amounts of pebbles were swallowed for ballast. The hind limbs would have been efficient for
terrestrial locomotion at maturity. The presence of long growth series for Hovasaurus and the
more terrestrial tangasaurid Thadeosaurus presents a unique opportunity to study differences in
growth strategies in two closely related Permian genera. At birth , the limbs were relatively
much shorter in Hovasaurus, but because of differences in growth rates, the limbs of Thadeosaurus
are relatively shorter at maturity. It is suggested that immature specimens of Hovasaurus
spent most of their time in the water, whereas adults spent more time on land for mating, laying
eggs and/or range dispersal. Specilizations in the vertebrae and carpus indicate close relationship
between Youngina and the tangasaurids, but eliminate tangasaurids from consideration
as ancestors of other aquatic eosuchians, archosaurs or sauropterygians.
Description
Main article
Keywords
eosuchian; Permian; Madagascar;
Citation
None