Dental and craneomandibular variability in Lestodelphys halli (marsupialia: Didelphimorphia) in northwestern Chubut Province (Argentina) and a new locality for Dromiciops gliroides (Microbiotheria).

MARTIN, G. M.

Mendoza

Jornada; XVI Jornadas Argentinas de Mastozoología; 2001

SAREM

The distribution and abundance of Patagonian marsupials is poorly known due to the lack of studies made in the area.  At least four species belonging to three different orders are said to inhabit this vast part of southern South America, and how these animals are adapted to live in this extreme environment is still a matter of debate.  Species like Lestodelphys halli are known from very few complete skeletons of trapped animals and several fragments recovered from owl pellets.By locating cliffs where Strigiform pellets and bone remains associated were found, I here present five new localities for this species including the westernmost site registered to date, located in the ecotone zone close to the Nothofagus forest near the city of Esquel. This is the biggest collection of Lestodelphys halli(almost 200remains) and it was used to establish the species’ dental and cranial measurements. A previous analysis of the intra-specific variation is discussed.  Measurements were compared with other living and extinct specimens cited in literature and some others that remained unmeasured.I also present the southernmost Argentine locality for Dromiciops gliroides and its external measurements, belonging to a male found in Río Azul, some 100 km. south of Bariloche city, where the only previous known specimens were located.