Phylogenetic relationships of the family Carditidae (Bivalvia: Archiheterodonta): a multi-analysis approach

PEREZ, DAMIÁN EDUARDO

San Luis

Jornada; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2017

Asociación Paleontológica Argentina

Carditidae family is a large group of bivalves that probably appears in the Triassic and has a highly diversification during the Paleogene. A phylogenetic study of the whole family was performed, using 77 species-taxa (including fossil and recent ones) and 144 morphological characters. Multiple searches were conducted, including discrete and continuous characters and equal and implied weighting. A time-calibrated phylogeny, a morphological disparity analysis, a phylomorphospace, and a phylogenetic signal analysis were obtained and performed from the character matrix. From the combination of all results, a new systematic scheme is suggested, including the proposed subfamilies Palaeocarditinae, Carditinae (which is re-defined), Thecaliinae (included within Carditinae in some searches), Carditamerinae (with a reduced diversity) and Venericardiinae (with an extended diversity). A new subfamily is proposed for the clade that contains Scalaricardita+Coripia+Vimentum. A temporal and morphological gap between Palaeocarditinae and the remaining carditids are recognized. This morphological gap is accompanied by several characters that related Palaeocarditinae with other Archiheterodonta families, including slightly prosogyrate umbos, presence of escutcheon, large lunule and right anterior tooth limited to a laminae adjacent to lunular margin. Other morphological groups are observed from the disparity analysis. From these results, three new clades above subfamily-level are suggested in consequence: Eucarditidae (comprising all carditids excluding Palaeocarditinae), Carditida (including Thecaliinae, Carditinae and Carditamerinae), and Cyclocardida (including Miodomeridiinae, the broadly diverse genera Cyclocardia and Pleuromeris, and the new subfamily).