Notes on the External Morphology, Ecology, and Origin of Megalomys Desmarestii (Sigmodontinae, Cricetidae, Rodentia), the Extinct Giant Rat of Martinique Island, Lesser Antilles/Markmed Martinique'i Saare (Vaikesed Antillid) Valjasurnud Hiidroti Megalomys Desmarestii (Sigmodontinae, Cricetidae, Rode

The giant rat of Martinique Island, Megalomys desmarestii (Fischer, 1829) became extinct at the end of the 19th or the very beginning of the 20th century. Little is known about its habits. The goal of this research was to reconstruct its ecology using the external and craniodental morphological characters of available museum specimens. On the basis of ecomorphological analysis some suggestions are made about the locomotor abilities, ecological strategies, adaptive evolution, and origin of this rodent. It is proposed that M. desmarestii foraged mostly on the ground and sheltered in burrows. Its main food was seeds and fruits, including nuts. It was crepuscular rather than strictly nocturnal or diurnal. The general trends of its adaptive evolution were: (1) increasing body size, (2) transition from an arboreal to a terrestrial/subterranean way of life, and (3) adaptation to eating hard-covered fruits. Thus, the ancestor of M. desmarestii was probably smaller and had arboreal or semiarboreal habits. The granulated structure of the soles of M. desmarestii's feet supports a close relationship with Nectomys.