CASADIO Silvio Alberto
CANNIBALISM IN NATICIDAE FROM THE LA MESETA FORMATION (EOCENE, ANTARCTICA)
BREZINA, S.S.; CECH, N.; MARTIN SERRALTA, D.; CASADIO, SILVIO
CAMBRIDGE UNIV PRESS
Lugar: Cambridge; Año: 2016
Polinices marambioensis Stilwell & Zinsmeister, is a naticid gastropod which is the most common constituent in fossil accumulations in the upper section of the Cucullaea I Allomember (Middle Eocene), of the La Meseta Formation, in the James Ross Basin of the Antarctic Peninsula. This species was an important predator of infaunal bivalves and gastropods, including other naticids. The aim of this work is to assess the pattern of predation and cannibalistic behavior of P. marambioensis. A total of 2,648 specimens of P. marambioensis were examined for drill holes, which were assigned to Oichnus paraboloides Bromley. Drilling frequency data were measured as a proxy for predation intensity and statistical analyses were performed. Also site of each drill hole was established according to the morphological features of the shell on each specimen to assess possible preference of predators for the site of perforation. Results suggest that P. marambioensis is an efficient cannibalistic predator for a specific size range of prey (8-22 mm), and drill holes are distributed preferentially in two specific sectors of their shells. This selective cannibalistic prey behavior in P. marambioensis affected not only the dynamics of their populations but the ecological structure of the community in which they lived.