Andrade, A.

Monjeau, A.

Nabte, M. J.

Saba, S. L.

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Check List 5(2): 320–324, 2009. ISSN: 1809-127X  NOTES ON GEOGRAPHIC DISTRIBUTION     320Mammalia, Rodentia, Sigmodontinae, Akodon molinae Contreras, 1968:  New locality records and filling gaps  Marcela Janina Nabte 1 Analía Andrade 1, 2 Sergio Leonardo Saba 1, 2 Adrián Monjeau 3  1 Centro Nacional Patagónico (CENPAT-CONICET). Boulevard Almirante Brown 2915, (9120). Puerto Madryn, Chubut, Argentina.  E-mail: nabte@cenpat.edu.ar  2 Facultad de Ciencias Naturales, Universidad Nacional de la Patagonia San Juan Bosco, Sede Puerto Madryn. Boulevard Almirante Brown 3700, (9120) Puerto Madryn, Chubut, Argentina.  3 Instituto de Análisis de Recursos Naturales, Universidad Atlántida Argentina Sede Mar del Plata. Arenales 2740, (7600) Mar del Plata, Buenos Aires, Argentina.    Akodon molinae Contreras, 1968 is a large (holotype: 42.5 g), diurnal species with long   and hispid fur, the dorsum is dark grey and the belly is whitish. The tail is shorter (holotype:   78 mm) than head and body (holotype: 108 mm), black dorsally and white in its centrally proximal third. The skull is large and strong, the zygomatic plate is wide and its edge is slightly convex   and directed obliquely backwards and down   (type description, Contreras 1968). The mandible has a short and robust coronoid process and   an anteromedian flexus/flexid on the first   upper and lower molars respectively, like other species in the genus Akodon. Cranial and   dental remains of A. molinae are shown in Figure 1.   The holotype was collected in vivero del Ministerio de Asuntos Agrarios, Laguna Chasicó, Buenos Aires province, Argentina, in grasslands near water bodies (Contreras 1968). Near the Atlantic coast, it lives in shrub steppes and halophilic plant communities (Daciuk 1974). Its distribution in northern Patagonia was associated with the Monte Phytogeographical Province (Pardiñas et al. 2003).   However, the distribution of these southern populations is still fragmented and poorly explored. Some authors have raised doubts about the taxonomic status of A. molinae (for the discussion on taxonomic aspects, see Wittouck et al. 1995, Pardiñas et al. 2003, 2006).    Figure 1. Akodon molinae collected in the Área Natural Protegida Península Valdés, province of Chubut (MN 37). 1: dorsal view 2: ventral view 3: lower right molars 4: right mandible in lateral view. Scale= 10 mm. Check List 5(2): 320–324, 2009. ISSN: 1809-127X  NOTES ON GEOGRAPHIC DISTRIBUTION     321 Braun et al. (2008) have suggested that the species A. molinae and A. dolores Thomas, 1916 are synonymous (with different chromosomal races, 2n=42-44 for A. molinae and 2n=34 for A. dolores) and A. dolores is the valid name for priority. In this work, we refer the studied specimens to the species A. molinae until this synonymy is broadly accepted.    In this paper, we present 23 new locality records for A. molinae in the provinces of Río Negro and Chubut and we discuss its distribution in northeastern Patagonia. The specimens were collected on two protected areas from the arid and semiarid extra-andean Patagonia in Argentina: Meseta de Somuncurá (Río Negro) and Área Natural Protegida Península Valdés (Chubut), and in some surrounding localities. Field work was conducted between 2004 and 2007.  Somuncurá is a 25,000 km2 volcanic plain located in the middle of the North extra-andean Patagonian steppes, lying in the provinces of Río Negro and Chubut. The vegetation is associated with the altitudinal gradient (between 600 - 1,600 m a.s.l. Beeskow et al. 1982). While the Monte Phytogeographical Province dominates the lower levels, the Patagonian Phytogeographical Province prevails above. These units gradually interchange species in an ecotone area (Ecotono Rionegrino, sensu León et al. 1998). Área Natural Protegida Península Valdés with its 4,000 km2 is located in northeastern Chubut, within the Monte Phytogeographical Province and Península Valdés Ecotone (Ecotono de la Península de Valdés, sensu León et al. 1998).   Collected material is mostly constituted by craniodental remains recovered from Barn Owl (Tyto alba; Aves, Ttytonidae), Magellanic Horned Owl (Bubo magellanicus; Aves, Strigidae) and Burrowing Owl (Athene cunicularia; Aves, Strigidae) pellets.  Osteological remains were picked apart from pellets and A. molinae was identified by comparison with the reference collection of the “Unidad de Arqueología y Antropología” and “Unidad de Ecología Terrestre”,  Centro Nacional Patagónico (CENPAT-CONICET), Puerto Madryn, Argentina. Additionally, some specimens were collected through live traps and pitfall traps. Animals were processed according to standard preparations (Díaz et al. 1998).  The material referred in this contribution is housed at Colección de Zooarqueología y Zoología, Unidad de Arqueología y Antropología, CENPAT-CONICET and is currently being processed, so catalog numbers are not yet available. Below we provided collector's field numbers to owl pellets (as lots, AA-E and MN-E) and to specimens collected in traps (AA and MN). New collecting localities (Figure 2) are listed below, from west to east, followed by specimen numbers:   1- Chipauquil, Río Negro (40°58' S, 66°39' W): AA 38, 39.  2- Estancia Liempi, Río Negro (41°39' S, 66°41' W): AA 217.  3- Estancia Los Manantiales, Río Negro (41°42' S, 66°37' W): AA 105, 120, 148.  4- Estancia El Luján, Río Negro (41°45'35" S, 66°32'03"W): AA-E 8.  5- Estancia El Luján, Río Negro (41°45'44" S, 66°32'21" W): AA-E 26.  6- Estancia Campana Mahuida, Río Negro (41°36' S, 66°26' W): AA-E 1.  7- Estancia El Porvenir, Río Negro (41°39' S, 66°24' W): AA 126, 128.  8- Quintas del Mirador, Puerto Madryn, Chubut (42°07' S, 65°02' W): MN-E 80.  9- Estancia La Juanita, Chubut (42°09' S, 65°03' W): MN-E 56.  10- Estancia La Esperanza, Chubut (42°08' S, 64° 57' W): MN-E 100.  11- Estancia La Esperanza, Chubut (42°11' S, 64°54' W): MN-E 116.  12- Estancia El Desempeño, Chubut (42°30' S, 64°44' W): MN-E 8, 121.  13- Estancia La Entrada, Chubut (42°24' S, 64°42' W): MN-E 87, 90, MN 462.  14- Estancia Las Charas, Chubut (42°29' S, 64°40' W): MN-E 15, 134.  15- Estancia El Pampero, Chubut (42°25' S, 64°36' W): MN-E 10, 131.  16- Estancia La Isla, Chubut (42°26' S, 64°33' W): MN-E 105.  17- Estancia La Anita, Campamento 39, Chubut (42°22' S, 64°03'W): MN 26.  18- Estancia Los Dos Hermanos (Puesto La Estrella), Chubut (42°46' S, 63°57' W): MN 280.  Check List 5(2): 320–324, 2009. ISSN: 1809-127X  NOTES ON GEOGRAPHIC DISTRIBUTION     32219- Estancia San Lorenzo, Chubut (42°07' S, 63°53' W): MN-E 3.  20- Estancia San Lorenzo, Chubut (42º05' S, 63º54' W): MN 37, 51, 57.  21- Estancia La Paloma, Chubut (42°39' S, 63°52' W): MN 120, 187, 204, 205, 396, 430, 432, 467. 22- Estancia Salina Chica, Chubut (42°39' S, 63°51' W): MN-E 7.  23- Estancia La Irma, Chubut (42°16' S, 63°41' W): MN 131, 375.   Localities 1-7 belong to Somuncurá Plateau; 9-23 to Península Valdés and 8 is located outside these Protected Areas.    The overall distribution of A. molinae in the study area is associated with the Monte Phyto-geographical Province. However, 11 of the 23 localities reported here are located within the ecotone area between the Monte and the Patagonian Phytogeographical Provinces (sensu León et al. 1998): the Rionegrino Ecotone (1, 2, 7) and the Península Valdés Ecotone (16 to 23).   Previous records of this rodent species in the Área Natural Protegida Península Valdés were from coastal localities at Isla de los Pájaros (Daciuk 1974), Playa El Doradillo (Apfelbaum and Reig 1989), Riacho San José (Massoia et al. 1988 [here mentioned as A. varius neocenus]) and Puerto Lobos (Udrizar Sauthier and Pardiñas 2006). Nabte et al. (2008) referred this species for the Protected Area but they did not detail in which localities it was registered. These localities are presented in this paper (12, 14 and 15). In or near Somuncurá, the species was previously recorded in Sierra Pailemán (Trejo and Lambertucci 2007), Estancia Campana Mahuida and Sierra Grande (Andrade 2007) and El Rincón (Pardiñas et al. 2003).    Figure 2.  New locality records for Akodon molinae in the province of Río Negro and Chubut (Patagonia, Argentina). Check List 5(2): 320–324, 2009. ISSN: 1809-127X  NOTES ON GEOGRAPHIC DISTRIBUTION     323Considering known locality records, the distribution of the Argentinean endemic  A. molinae could be delimited approximately   from 31º S in the north (Córdoba province, Wittouck et al. 1995) to Laguna Blanca, 15 km south of Puerto Madryn, in the southeast (Chubut province, De Santis and Pagnoni 1989). Some   of those localities are within or near the limits   of the Espinal Phytogeographical Province (sensu Cabrera 1971). Even the type locality of   A. molinae is within those limits (a summary of the distribution in central Argentina was performed by Pardiñas et al. 2004).   The 23 new records reported in this paper contribute to fill in the information gaps of   the poorly known A. molinae and to broaden   its distribution towards the west within   northern Patagonia. This paper also reaffirms   its distribution in association with the   Monte Phytogeographical Province and extends   it into ecotone areas with the Patagonian Phytogeographical Province (Ecotono Rionegrino and Ecotono de la Península Valdés), in agreement with Pardiñas et al. (2003) who proposed the ingression of A. molinae into the Rionegrino Ecotone. It is important to notice that if the synonymy of A. molinae and A. dolores is accepted, the distribution of this species will be widely extended.   Meseta de Somuncurá and Península Valdés were declared as a Protected Area by the Provincial Government of Río Negro and Chubut respectively. As for most of Patagonia, both areas have been grazed since the beginning of the twentieth century. There is evidence that grazing by domestic herbivores has modified the vegetation and accelerated soil degradation processes (e.g. Beeskow et al. 1987; Rostagno and del Valle 1988; Bisigato and Bertiller 1997). It would be necessary to evaluate the possible influence of ovine and goats livestock on the   A. molinae populations, to protect the biodiversity of those reserves.   ————————————————  Acknowledgements We are grateful to Tana, Pablo Moro, Sebastián Zamora, María Florencia del Castillo Bernal, Daniel Udrizar Sauthier, Ulyses Pardiñas and all the rural settlers that helped us during field work. Mauricio Failla, “Director de Fauna del Ministerio de Producción”, Río Negro and the “Subsecretaría de Turismo y Áreas Protegidas”, Chubut, granted the animal capture permits. Guillermo D’Elia and Pablo E. Ortiz improved the manuscript with their suggestions. This work was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, Argentina), and partially supported by the “Administración del Área Natural Protegida Península Valdés” and the “Universidad Nacional de la Patagonia San Juan Bosco”.  ————————————————  Literature cited Andrade, A. 2007. 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Mammalia, Rodentia, Sigmodontinae, <i>Akodon molinae</i> Contreras, 1968: New locality records and filling gaps

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