Characterization of deposits of Pomacea canaliculata (Gastropoda: Ampullariidae) accumulated by snail kites: paleobiological implications

CLAUDIO G. DE FRANCESCO, LAURA M. BIONDI, KARINA B. SANCHEZ; BIONDI, LAURA MARINA; KARINA SANCHEZ

IBERUS (MADRID)

Sociedad Española de Malacología

Lugar: Madrid; Año: 2006 vol. 24 p. 39 - 46

0212-3010

We studied the main taphonomic attributes (breakage, orientation and size-frequency distribution)of modern shell piles of Pomacea canaliculata (Lamarck) accumulated by snailkites, in order to establish distinctive characteristics that allow the recognition of similardeposits in the fossil record. The study was conducted around three shallow lakes situatedin southeastern Buenos Aires Province, Argentina: Los Padres (37° 56’ S; 57° 44’ W),Nahuel Rucá (37° 37’ S; 57° 25’ W) and Hinojales (37° 34’ S; 57° 27 ’W). Shells werecollected from three different types of piles: (1) on the surface in the littoral zone (2) underneathwire fences and (3) underneath trees. 63 % of predated shells had light damage onthe outer lip, 17 % were intact. Dispersion of shells in each pile appeared to be related tothe surface available to the snail kite for perching rather than to its relative height. Consumedshells varied from 23 to 66 mm indicating selection of sexually mature individualsby snail kites. In conclusion, the outer lip damage and size range of predated P. canaliculatashells are distinctive attributes that allow the recognition of similar deposits in the fossilrecord.