Shell morphometric variation of Ameghinomya antiqua (Mollusca, Bivalvia) during the late quaternary reflects environmental changes in North Patagonia, Argentina

MORÁN, ARIANA GISELA; MARTÍNEZ, JUAN J.; BORETTO, GABRIELLA M.; GORDILLO, SANDRA; BOIDI, FLAVIA J.

QUATERNARY INTERNATIONAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2018

1040-6182

Mollusk shells have shown to be useful as biological proxies for palaeo environmental reconstructions. In thisstudy we perform an integral assessment of geometric morphometrics of Ameghinomya antiqua shells from SanMatías Gulf (SMG) (Patagonia, Argentina) with special attention on the protected natural area Caleta de LosLoros. In order to relate morphological variation with environmental changes, we analyzed size and shape variationfrom Holocene and modern shells (temporal variation) and from within the gulf (spatial variation) by carryingout landmark and semilandmark morphometrics studies. Results showed that Holocene shells were rounderand larger than modern ones, with posterior muscle scar, cardinal teeth and ligament more developed. Thesefeatures in Holocene shells from Caleta de Los Loros could be a response to a higher degree of mechanical stabilityin a high-energy habitat. Besides, morphometric differences in modern shells in SMG could be linked tovariations in wave action, tidal influences, sea surface temperature substrate and/or predation pressure, whichmodify the shape and size of this species. This study allows highlighting the phenotypic plasticity of A. antiquaas a possible response to different environmental conditions making this species a good proxy when evaluatingenvironmental changes.