Ctenomys mendocinus

MARIA ROSI; MÓNICA I. CONA; VIRGILIO ROIG; MASSARINI A.

MAMMALIAN SPECIES

Oxford University Press

Año: 2005

0076-3519

Ctenomys mendocinus shares the following characters withcongeners: broad rostrum, prominently ridged parietals without sag-ittal crest, well-developed lambdoid crest, jugals with prominentdorsally projected processes, enlarged infraorbital foramina with nocanal for nerve transmission, and large bullae with flat paraoccipitalprocesses joined to them. Mandibles have moderately developedcoronoid processes and wide angular processes that flare outwardly.Cheekteeth are kidney-shaped; 3rd molars are vestigial. Upper in-cisors are nearly orthodont and roots extend to start of cheekteeth(Ellerman 1940). Enamel of incisors is dark orange (Stein 2000).C. mendocinus occurs in northern andcentral Mendoza Province of Argentina (Fig. 3) from ca. 31 Њ S to34 Њ S and from Andean Precordillera eastward across arid sub-An-dean regions (Rosi et al. 2002). Records in adjoining provinces ofSan Luis and San Juan are scarce, and thus northern and easternlimits of distribution are not well delineated. Elevation at locationsof known occurrence ranges from 460 to 3,400 m (Rosi et al. 2002).A wider geographic range (Cabrera 1961; Honacki et al. 1982;Redford and Eisenberg 1992; Woods 1993) included taxa that noware recognized as distinct species.In Mendoza Province, populations occur in open scrublandsin the Andean Piedmont, where Atriplex lampa, Larrea cuneifolia,and L. divaricata are dominant (Pearson and Lagiglia 1992; Puiget al. 1999; Rosi et al. 1992b).Burrow systems of C. mendocinus from 2 habitats of MendozaProvince have a linear configuration, with a main axis from whichlateral tunnels and branches fork off.Herbivory by C. mendocinus on shrubs, estimated by per-centages of cut-off stems, affects 39% of total plants in Villavicen-cio and 9% in Divisadero Largo Reserve (Mendoza Province). Themost highly damaged species are Larrea divaricata (65%), Lyciumchilensis (41%), Junellia seriphioides (38%), and Menodora de-cemfida (33%) in Villavicencio.Ctenomys mendocinus is a solitary fossorialrodent with strongly territorial behavior as evidenced by capture ofonly 1 specimen per burrow system, even during the reproductiveseason (Puig et al. 1992), and absence of linking tunnels betweenneighboring systems (Rosi et al. 1996a, 2000). Individuals are ac-tive throughout the year, but winter snowfall and ground freezingin high mountain habitats reduce burrowing activities. At the be-ginning of spring when snow has melted, number of active burrowholes is 4.25 times lower than in the fall (Puig et al. 1992).Feeding behavior of captive C. mendocinus is characterizedby an opportunistic harvest pattern and selective consumption pat-tern. Animals harvest a wide variety of plants but prefer to eataboveground parts of grasses and generally avoid shrubs and roots(Camı ́n and Madoery 1994). Signs of aboveground foraging, suchas cut-off stems of shrubs, grasses, and cacti, occur near or aroundburrow openings (Camı ́n et al. 1995; Puig et al. 1992). These signsand the large proportion of aerial plant material in the diet of C.mendocinus indicate that foraging on the surface is common (Rosiet al. 2003)