A redescription of Malvinasia Cooper & Preston, 1910 (Bivalvia: Galeommatoidea), with the description of a new species

Abstract

After its original description, the bivalve genus Malvinasia Cooper & Preston, 1910 was regarded as a junior synonym of Mysella or Rochefortia. However, due to the recent changes proposed in the classification and the concept of 'mysellids', the current status and concept of this genus remains unclear. In the present study, the relationships of the genus Malvinasia with Mysella, Rochefortia, Rochefortula and Altenaeum are reanalysed, based on the study of Malvinasia arthuri Cooper & Preston, 1910, the type species of the genus. This species has a resilifer markedly introverted below the umbones and a right valve with a single, peg-like tooth, located anterior to the ligament. This peculiar hinge morphology is consistent throughout ontogeny in the genus, being present in at least four other South American morphospecies. Based on this evidence Malvinasia is considered a full genus, which is redescribed. In addition, Malvinasia piccola, a new species from the Atlantic coast of southern Patagonia is described and Mysella (Rochefortia) molinae Ramorino, 1968 is reallocated to Malvinasia. Information on the gross anatomy of this genus is provided by first time.