Phylogenetic analysis of the genusRetrotapesdel Río, 1997 (Bivalvia, Veneridae) and systematic analysis of its taxa from Chile

Abstract

AbstractSince the genusRetrotapeswas erected, some authors have favored or opposed its validity, or argued about the assignment of the extant speciesR.exalbidusandR.lenticularistoRetrotapes. Some authors synonymizedRetrotapeswith the Miocene genusFrigichione, and others with the extant genusEurhomaleato which most of the species that belong toRetrotapeswere previously assigned. In the present contribution, a phylogenetic analysis of the genus is performed to test these controversies. In addition, a systematic revision of the Chilean species of the genus is performed to complete the analysis ofRetrotapestaxa from Patagonia and Antarctica started by previous authors. This study demonstrates thatRetrotapesis a monophyletic genus, which is not closely related toFrigichioneorEurhomalea. Instead,Retrotapesis closely related to some Austral taxa from Kerguelen Island (Paleomarcia), New Zealand (Atamarcia), and Australia (Katelysia), a relationship previously unknown. Besides, the extant speciesR.lenticularisandR.exalbidusbelong toRetrotapesand were recovered as part of a clade closely related to the type species of the genus,R.ninfasiensis(Miocene, Patagonia).Retrotapesis reported in Chile beginning in the late Eocene, where it was represented byR.difficilisn. comb., which is a taxon that resembles some Eocene species of the same genus from Antarctica. In the late Oligocene–early Miocene, it was represented byR.navidadisand later in the Pliocene by three species: the fossilR.fuenzalidaeand the two extant ones.