A new genus of the 'Pitar' group (Bivalvia: Veneridae) from the Western Atlantic Ocean revealed by geometric morphometric analysis.

Understanding shell morphology is central to taxonomic and evolutionary studies of bivalves. When traditional systematic studies find limitations in the recognition and classification of taxa, geometric morphometrics methods become a tool to tackle these uncertainties. Taxonomic difficulties are frequently found in systematics studies of the generally homoplastic Pitarinae (Venereidae).

Allometric shell growth in infaunal burrowing bivalves: examples of the archiheterodonts (Ihering, 1903) and Ihering, 1899.

We present two cases of study of ontogenetic allometry in outlines of bivalves using longitudinal data, a rarity among fossils, based on the preserved post-larval record of shells. The examples are two infaunal burrowing bivalves of the southern South America, (Archiheterodonta: Carditidae) (early Paleocene) and (Archiheterodonta: Crassatellidae) (late Oligocene-late Miocene). Outline analyses were conducted using a geometric morphometric approach (Elliptic Fourier Analysis), obtaining successive outlines from shells' growth lines, which were used to reconstruct ontogenetic trajectories.

Systematics of the family Carditidae (Bivalvia: Archiheterodonta) in the Cenozoic of Argentina.

The systematics of the Family Carditidae is currently poorly elucidated. This paper reviews the Eocene to Pleistocene carditids from Patagonia and Entre Ríos Province (Argentina). Twelve species are described and illustrated and the presence of the genera Cyclocardia Conrad, Pleuromeris Conrad, Scalaricardita Sacco, Fasciculicardia Maxwell and Purpurocardia Maxwell in southern South America is discussed.