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Noteworthy records of mammals from the Orinoco River drainage of Venezuela.

The most thorough documentation of mammals found in Venezuela resulted from the Smithsonian Venezuelan project with field work occurring between 1965 and 1968 (Handley 1976). One area that was sparsely sampled, however, was the transition region from savanna to rainforest south of the Orinoco River (Ochoa et al. 1988; 1993). This paper presents noteworthy records of small mammals from a collecting trip to the Llanos region in central Venezuela and includes range extensions for six taxa (Pteronotus gymnonotus, Lonchorhina orinocensis, Lonchophylla thomasi, Mus musculus, Rhipidomys leucodactylus and Sylvilagus floridanus).

Mammals reported in this paper were collected in July and August 1997 from five localities within the Orinoco River drainage basin. The habitat of locality 1 was a mix of riparian forest along the Orinoco River with granite outcrops and forested hills within savanna (Amazonas; Pozon, 50 km NE of Puerto Ayacucho, 6[degrees] 3'N, 67[degrees] 25'W). In addition, because it was the rainy season, much of the savanna and all of the riparian forests were flooded. Locality 2 was a cattle ranch on the Llanos (Bolivar; Hato La Florida, 35 km ESE of Caicara, 7[degrees] 34'N, 65[degrees] 52'W). The habitat was savanna with many small creeks and swamps. There were also granite outcrops and isolated mountains that were forested. Locality 3 was gallery forest in savanna near a river about 50 m across and bordering a ranch (Bolivar; 20 km S of Guaniamo, 6[degrees] 26'N 66[degrees] 7'W). Locality 4 was the only collecting site north of the Orinoco River (Guarico; Rio Orituco 10 km W of Chaguaramas, 9[degrees] 24'N, 68[degrees] 28'W). This site consisted of extensive (mixed-grain crop) cultivated fields with a secondary growth riparian forest, in conjunction with a major highway and bridge. Locality 5 was an old secondary growth forest near the Caura River (Bolivar; 3 km E of Puerto Cabello del Caura, 7[degrees] 10'N, 64[degrees] 50'W). Some trees in this locality were large with buttressed roots and there were epiphytes in the canopy. There were, however, cultivated fields in the vicinity with many roads and trails in the area. Voucher specimens were deposited in the Abilene Christian University Natural History Collection (ACUNHC) and the Royal Ontario Museum (ROM).

Pteronotus gymnonotus Natterer. -- Handley (1976) reported this species from localities north of the coastal mountains in northwestern Venezuela, with most captures in dry areas. One lactating female (ROM 107925) was caught (at locality 2) over a pond in riparian forest south of the Orinoco River.

Lonchorhina orinocensis Linares & Ojasti. -- Records of this species are documented from near the border with Colombia in southwestern Venezuela (Handley 1976). This study provides documentation of specimens from south central Venezuela (locality 2) about 200 km. east of the most proximate recorded locality. Five specimens (ROM 107911, ROM 107912, ACUNHC 302, ACUNHC 375 and ACUNHC 376) were collected from an isolated igneous rock outcrop within savanna. Four were pregnant with embryo crown-rump (CR) measurements ranging from 7 to 11mm and the fifth female was lactating. The outcrop contained several large crevices in which L. orinocensis roosted with Micronycteris megalotis, Saccopteryx bilineata and Peropteryx macrotis. An additional 15 specimens of L. orinocensis were collected at locality 1 in savanna mixed with patches of forest and rock outcrops. Of the 11 females, all were pregnant, with embryo CR ranging from 6 to 20mm.

Lonchophylla thomasi Allen. -- One male (ROM 107906) was caught (locality 3) about 150 km north of the most proximal documented locality in Venezuela (Handley 1976). Eisenberg (1989) reported a disjunct distribution for this species, south of the Orinoco River and west of the Andes in Colombia and Panama. The animal was caught in riparian habitat along a river that was about 50 m across. A second male (ACUNHC 395) was collected from locality 5 in an agriculturally disturbed rainforest. This species is usually associated with evergreen forests (Handley 1976).

Rhipidomys leucodactylus Tshudi. -- A non-pregnant female (ROM 107873) was collected at locality 1, 300 km NNW of the next most proximal record in southern Venezuela (Handley 1976). The animal was trapped in a small (7 m tall) tree that was growing over an igneous rock outcrop. There was a stream on one side of the rock outcrop and flooded llanos on the other side. This is the first documentation of R. leucodactylus from riparian habitat in the Llanos. Previous records are from primarily moist, evergreen forests (Handley 1976).

Mus musculus Linnaeus. -- All the recorded localities for this species are in association with the large cities and towns long the Caribbean coast of Venezuela or in the adjacent mountains (Handley 1976; Eisenberg 1989). A pregnant female (ACUNHC 272) with four embryos (CR = 13) was collected about 70 km south of the coastal mountains in the Llanos (locality 4). It was caught in a farm house which was next to the Orituco River.

Sylvilagus floridanus Allen. -- The previously reported range for this species in Venezuela was north of the Orinoco River (Eisenberg 1989). This study documents the existence of the species southeast of the Orinoco River (locality 1). One male (ROM 107864) was shot on a dry grassy hill in the Llanos by a local hunter. An additional specimen (ACUNHC 266) was found as a roadkill north of the Orinoco River (Guarico; 10 km NE of Las Mercedes, 9[degrees] 11'N 66[degrees] 20'W). There were also several sightings along Highway 12 between Las Mercedes and Puerto Ayacucho in the savanna.

ACKNOWLEDGMENTS

We thank the Biology Department at Abilene Christian University and the Abilene Christian University Math/Science research grant to T. E. Lee for supporting the project. Daniel Lew, Silvia Armitano and the Armitano family provide much needed logistical support in Venezuela.

LITERATURE CITED

Eisenberg, J. F. 1989. Mammals of the Neotropics, the northern Neotropics, volume 1. Panama, Colombia, Venezuela, Guyana, Suriname, French Guiana. The University of Chicago Press, Chicago, 449 pp.

Handley, C. O., Jr. 1976. Mammals of the Smithsonian Venezuela project. Brigham Young University Science Bulletin, Biological Series, 20(5):1-91.

Ochoa G. J., J. Sanchez H., M. Bevilaqua & R. Rivero. 1988. Inventario y estudio comunitario de los mamiferos de la Reserva Forestal de Ticoporo y la Serrania de los Pijiguaos, Venezuela. Acta Cientifica Venezolana, 39:269-280.

Ochoa G. J., C. Molina & S. Giner. 1993. Inventario y estudio comunitario de los mamiferos del Parque Nacional Canaima, con una lista de las especies registradas para la Guayana Venezolana. Acta Cientifica Venezolana, 44:245-262.

Thomas E. Lee, Jr., Burton K. Lim* and John D. Hanson

Department of Biology, Box 27868

Abilene Christian University, Abilene, Texas 79699

*Center for Biodiversity & Conservation Biology

Royal Ontario Museum, 100 Queen's Park

Toronto, Ontario, Canada M5S 2C6

TEL at: lee@biology.acu.edu
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Title Annotation:GENERAL NOTES
Author:Lee, Thomas E., Jr.; Lim, Burton K.; Hanson, John D.
Publication:The Texas Journal of Science
Geographic Code:3VENE
Date:Aug 1, 2000
Words:1112
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