OVERVIEW OF THE HISTORY OF DISCOVERY, TAXONOMY, PHYLOGENY, AND BIOGEOGRAPHY OF MAJUNGASAURUS CRENATISSIMUS (THEROPODA: ABELISAURIDAE) FROM THE LATE CRETACEOUS OF MADAGASCAR

Abstract

ABSTRACT We review the historical sequence of discoveries of Majungasaurus crenatissimus, an abelisaurid theropod from the Upper Cretaceous (Maastrichtian) Maevarano Formation, Mahajanga Basin, northwestern Madagascar. For almost a century, beginning in 1895, periodic expeditions conducted by French, Japanese, and Malagasy teams yielded fragmentary and isolated remains of a medium-sized theropod dinosaur from the Maevarano Formation. These materials were first assigned to Megalosaurus crenatissimus but later to Dryptosaurus crenatissimus, then Majungasaurus crenatissimus, and, most recently, Majungatholus atopus. The taxon was variously considered to pertain to Tyrannosauridae, “Megalosauridae,” and Abelisauridae. Recent excavations undertaken by the Mahajanga Basin Project (1993 to present) have resulted in abundant and spectacular remains of this theropod. The new material allows us to establish Majungasaurus crenatissimus as the valid name for this theropod and to conclusively place it within Abelisauridae. M. crenatissimus is currently known from multiple specimens of various size (and presumably age) classes, which cumulatively represent the great majority of the skull and skeleton. Together, these finds establish Majungasaurus as among the best known of Gondwanan theropods. M. crenatissimus is one of several vertebrate taxa recovered from the Maevarano Formation that indicate close biogeographic ties linking Madagascar with the Indian subcontinent and South America. These data support the hypothesis of a high degree of cosmopolitanism among these landmasses, the result of a persistent subaerial connection between Indo-Madagascar to the east and South America to the west (possibly through Antarctica) until sometime late in the Late Cretaceous.