TELMATOBIUS OXYCEPHALUS (NCN) PREDATION

BRUNETTI, A. E.

HERPETOLOGICAL REVIEW

Society for the Study of Amphibians and Reptiles

Lugar: Salt Lake City, USA; Año: 2008 vol. 39 p. 462 - 463

0018-084X

TELMATOBIUS OXYCEPHALUS (NCN) PREDATIONHerein I report two cases of predation on juveniles and adults Telmatobius oxycephalus.The observations were made during field work at two branches of a small stream tributaryof Huasamayo river 10 km from the city of Tilcara, province of Jujuy, northern Argentinaduring 15–17Aug, 18-21 Dec, 27-30Dec, 2006 and 29Jan-1Feb 2007.On 31 Jan 2007 at 2110h, a non adult wolf spider (Lycosa sp gr thorrelli (Lycosidae)) wasobserved hidden under a small rock at the margin of a small branch of the stream (maxwidth 1m) prying upon a juvenile T. oxycephalus. Only the hindlegs of the frog weredistinguishable because the spider covered with its body the rest of the specimen. At thetime of the finding the frog was already dead and presented a large area of necrotic tissue inthe dorsal area and a loose color in the whole body. The spider stayed still for ca. 10minutes and left the prey once was tried to collect it.On 12 Dec 2006 at 2000h, a rainbow trout (Oncorhynchus mykiss) was collected at a pondat 30cm from the stream. The pond is ca. 150 x 80cm, 50cm depth, and has clear water; itstemperature was 9ºC, and air temperature was 17ºC. As the pond did not have directconnection with the stream it is possible that the trout got there after a flood that occurredin the area a week before the observations. New searches were done under the stones at themargin and found a live T. oxycephalus female SVL=44.8 cm. Upon dissection of the trout,an adult T oxycephalus (SVL=45cm) in an intermediate state of preservation was found inthe stomach. The locals inhabitants in the area informed that annually, since at least threeyears ago, people have been releasing alevines of rainbow trout but summer floods causehigh mortality and drive the adults downstream where they probably die mainly because ofturbidity. Additional searches were conducted at the site but no other trouts were found.The observations reported here clearly indicate that introduced salmonids do predate onTelmatobius. Although always suspected (e.g. Merino-Viteri et. al., 2005 Monog. Herpetol.7:9-37), we are not aware of any single published report of actual predation, so this one ispossibly the first one, despite, there exist some examples of predation upon many anurans(e.g. Lips et. al., 2005. Biotropica 37 (2), 222–226, Fox et. al., 2005 Copeia, (4), pp. 921–929, Bradford et. al., 1993 Cons. Biol. 7 (4) 882-888. Katz et. al., 2003 Div. and Distrib.9:99-110). Whether this occurs at a scale that could drive local populations to extinction, asalready suggested for Telmatobius ceiorum (Barrionuevo y Ponnsa, 2007 in press) remainsto be studied.