Small mammals of the atlantic continental sector of central Patagonia: taxonomy and geographic distribution

UDRIZAR SAUTHIER, D. E.; SANCHEZ, J.P; UDRIZAR SAUTHIER, W.O.

Mendoza

Congreso; 10 th International Mammalogical Congress; 2009

In extraandean Patagonia diverse environments are found, from shrubby formation of the northeastern to the arid steppes of the south. The knowledge about the small mammal assemblages in vast areas of this region is still very poor. The aim of this contribution is to improve the knowledge of small mammal assemblages that occur throughout the Atlantic sector (ca. 30 km from the coast line) of Chubut province (42º-46ºS). The field work was carried out in 7 localities: Puerto Lobos (42º00'02"S, 65º04'10"W), Bahía Cracker (42º57'02"S, 64º28'45"W), Bajo de los Huesos (43º11'42"S, 64º51'52"W), Isla Escondida (43º 41'46"S, 65º20'36"W), Cabo Raso (44º20'22"S, 65º14'59"W), Puerto Piojo (44º53'00"S, 65º40'19"W) and Pico Salamanca (45º24'32"S, 67º24'58"W). In these localities 200 traps (Sherman) were used, remaining in the field between 2-5 nights in each locality. We captured 324 specimens, totalized at least 13 species of small mammals: 2 of marsupials, 9 of sigmodontine rodents and 2 of caviomorph rodents. The taxonomic structure reflects a change between northern and southern assemblages, coherent with the two major floristic units (FU) present in the area: Monte Phytogeographic province (Pp) and Patagonica Pp. Monte Pp (until 44ºS) is represented by an exclusive species: Akodon molinae (5,98% [percentage of capture in each FU]), another species captured in this FU were Eligmodontia sp. (42,66%), Akodon iniscatus (25,78%), Graomys griseoflavus (19,65%), Thylamys pallidior (4,23%), Reithrodon auritus (1,70%), Calomys musculinus (0.85%) and Ctenomys sp. (0.85%). In the Patagonica Pp were exclusively captured Abrothrix olivaceus (17,07%), Phyllotis xanthopygus (11,21) and Lestodelphys halli (1,46%), together with Eligmodontia sp. (29,30), G. griseoflavus (14,63%), R. auritus (9,26%), A. iniscatus (9,26%), C. musculinus (3,41%), Microcavia australis (1,95%), Ctenomys sp. (1,95%) and T. pallidior (0,48%). The changes between the small mammal assemblages of these two Pp seem to be tie with latitudinal and altitudinal gradients that influenced the geographic distribution of taxa.