Holocene subfossil rodents from the Lavajaza Cave, Central Highlands of Madagascar

摘要

Subfossil rodents are relatively rare in the Holocene fossil record of Madagascar. Caves and different forms of rock shelters can contain considerable quantities of rodent remains, which for the most part are deposited by avian predators. The Lavajaza Cave discovered in the late XIXth?century is situated near Antsirabe in the Central Highlands of Madagascar and a detailed analysis of the rodent remains from the site have not been published. Based on morphology and morphometrics, we identified four rodent species from the remains, belonging to two endemic species (Nesomyidae) and two invasive species (Muridae). No radiocarbon dates are available from the rodent remains. The assemblage is dominated by the two murids Rattus rattus and Mus musculus, which are presumed to have been introduced to the island sometime after the 11th-century. The two native rodents are Brachyuromys betsileoensis and B.?ramirohitra, both known from montane forests and the former also from marsh habitat. These taxa collectively indicate the presence of forest habitat in the vicinity of Lavajaza until at least 1900 before intensive anthropogenic ecological modifications.