Shell morphology of a new Brazilian species of the family Kelliellidae, with a brief review of the genus Kelliella (Mollusca: Bivalvia)

The bivalves of the families Vesicomyidae and Kelliellidae are common bottom inhabitants of the deep-sea, with some taxonomic controversy concerning the smaller forms of the former, which are frequently confused as species of the latter. Based on specimens collected from shallow waters of the southeastern Brazilian coast, a new species of Kelliella is described, through a detailed description of its shell, which is compared with those from other species already referred for this genus. Its minute valves with rounded contour and a marked lunule are very similar to those of K. miliaris , the type-species of kelliellids, differing in only some details of the hinge dentition. Most species of the genus Kelliella are currently assigned to the genus Vesicomya , causing great difficulties as far as knowledge of the real diversity of the family Kelliellidae. This study represents part of a continuing work on new discoveries regarding the marine molluscs of the southwestern Atlantic. Here, a review of the genus Kelliella is provided, highlighting some shell features that will be important in future comparative studies between these bivalve families.