Majoria - Ecology, Behavior, and Extinction

Ecology, Behavior, and Extinction

The forelimbs of Plesiorycteropus show specializations for scratch-digging, in which the forefeet are placed against the substrate, the claws are entered into the substrate, and the forefeet are then drawn back against the body. Other parts of the body also show such specializations, including large hindlimbs and a broad tail. Some aspects of the vertebral column and the pelvis suggest that the animal often assumed an erect, or sitting, posture. The animal may also have been capable of climbing, perhaps in a manner similar to gymnures and shrew tenrecs, which are small-eyed like Plesiorycteropus. It was probably myrmecophagous, eating insects such as ants and termites, but may also have eaten other soft food, and because of its small size probably did not forage in termite mounds, as the aardvark does.

MacPhee had material of Plesiorycteropus from twelve sites in central, western, and southern Madagascar. It and other recently extinct Madagascar mammals may have lived in and near wetlands. P. madagascariensis is known from sites throughout this range, but P. germainepetterae has only been definitely recorded from the center; small bones from southern sites may also belong to it. Thus, the two species apparently had widely overlapping ranges.

Little is known about the extinction of Plesiorycteropus, but MacPhee assumed it may have happened around 1000 years ago, when the extinction of the rest of the subfossil fauna of Madagascar is thought to have concluded. Nothing like it was reported by 17th-century European explorers of the island, and one bone has been radiocarbon dated to around 2150 Before Present (200 BCE). Its extinction is somewhat anomalous, as other recently extinct Madagascan animals—such as subfossil lemurs, Malagasy hippopotamuses, the giant fossa, and elephantbirds—were generally larger and not exclusively insectivorous; also, some species with likely more specialized diets, such as the falanouc (Eupleres goudoti) and aye-aye (Daubentonia madagascariensis), did survive. Early human colonists of Madagascar may have caused the extinction of Plesiorycteropus through the destruction of the forest and other disturbances.