A NEW FOSSIL RODENT FROM THE HOLOCENE OF BONAIRE, NETHERLANDS ANTILLES

During the late Quaternary, several lineages of muroid rodents entered the West Indies by over-water dispersal from Central and South America. Only one of these lineages persists to the present day, although several survived into the 19th and 20th centuries. In the Netherlands Antilles of Aruba, Curaçao and Bonaire, Aruba received only the vesper mouse, Calomys. Curaçao hosted the capybara, Hydrochaeris, a giant rice rat, Megalomys, a smaller endemic rice rat, Oryzomys, and Calomys. Until now, the only rodent known from Bonaire has been an undescribed Thomasomys sp. from indurated breccias of probable pre-Sanagmonian age. Recent excavations in unconsolidated cave sediments of Cueba Curado, Bonaire, have recovered remains of an undescribed, extinct, oryzomyine rodent. Based on fluorine relative dating results, AMS ¹⁴C dating is expected to yield a middle-to-late Holocene age for this deposit. The new Bonaire oryzomyine adds to the growing understanding of the late Quaternary biogeography of this vagile group.