PHYLOGENETIC RELATIONSHIPS OF CENOZOIC PITARINAE (BIVALVIA: VENERIDAE) FROM ARGENTINA

DEL RIO, CLAUDIA JULIA; ALVAREZ, MAXIMILIANO

Buenos Aires

Congreso; Hennig XXX5 XII Reunión Argentina de Cladística y Biogeografía; 2016

The confused systematic information prevailing during almost the last 100 years, has mixed up the history of the Pitarinae genera of Argentina with those of Amiantis, Macrocallista and Pitar, leading to misinterpretations about their origin, dispersion and phylogenetic relationships. To test the affinities ofthe Pitarinae of Argentina we performed a cladistic analysis based on 72 shell-characters of 28 species. The Oligocene?Recent genera Austrocallista, Eucallista, and ?Pitar? from Chile and southwestern Atlantic Ocean were considered as ingroup, along with the type species of Pitar (P. tumens [Recent; Senegal]), Amiantis (A. callosa [Late Miocene?Recent; California]), Lamelliconcha (L. concinna [Recent; Baja California to Peru]), and Macrocallista (M. nimbosa [Recent; North Carolina to Mexico]) and the species A. mathewsonii (Oligocene?Late Miocene; California), L. alternata (Recent; Panama to Peru),and L. circinata (Recent; Caribbean Sea to Brazil). Additionally, we considered 11 species of the Subfamily Pitarinae and one of the Dosiniinae as outgroup. We obtained a topology where Austrocallista and Eucallista are sisters groups being clustered with Amiantis through the presence of a sculptured nymph. Besides, the species of ?Pitar? from Argentina constitute a monophyletic clade more related to Lamelliconcha than with the species of ?Pitar? from Brazil, which in turn, are grouped with Pitar tumens. Our results allowed us to confirm that Austrocallista and Eucallista are valid genera, and lead us to erecta new genus for those fossil and Recent Argentine species ?P?. mutabile and ?P?. patagonica, respectively, previously included in Pitar s.str.