Evidence of durophagy in the Holocene gastropod Buccinanops defprmis (King, 1831) at Bahía Blanca, Argentina

GOMEZ ESPINOSA C.; FARINATI E.; ALIOTTA S.

Mexico DF

Congreso; Mollusca 2014; 2014

Univ. Nacional Autónoma de Mexico - American Malacological Society

The genus Buccinanops (d'Orbigny, 1841) (Caenogastropoda, Nassarriidae) is endemic to the SW Atlantic Ocean, from Rio de Janeiro, Brazil to San Matías Gulf, Argentina. This genus has a geological record extending from the Upper Miocene to the present day. Samples come from the Holocene sand shell ridges at the inner part of the Bahia Blanca estuary, Buenos Aires Province, Argentina. The aim of this study is to identify evidence of durophagous predation on the holocene gastropod Buccinanops deformis (King, 1831) and evaluate quantitatively frequency of predation, scars repaired and the prey effectiveness. The predatory-prey interactions are difficult to study in the fossil record because most predators leave no trace or destroy the hard parts of their prey. The fossil record of predation in gastropod has focus most of the times in the drilling predation and less attention has been paid to the shell breakage induced by durophagy. The presence of lethal (breakage) and sublethal predation (repaired scars) were examined for each shell under a dissecting stereo-microscope. The shells of B. deformis studied exhibit predatory damage including signal of lethal and sublethal attacks. Some of the Buccinanops shell breakage, lethal and repaired scars show injuries of the kind of large embayed fracture of the body whorl; this kind of damage has been observed as product of predation by crabs. A low repair scar frequency (6%) and low prey effectiveness (37%) in B. deformis at the Holocene sand shell ridges in Bahía Blanca can be interpreted as the result of low but effective predatory activity.