A tribo Marginellini Fleming, 1828 na costa brasileira (Mollusca, Gastropoda, Marginellidae)

Abstract

The generic and specific taxonomy of the tribe Marginellini Fleming, 1828 is examined. This study was based on fossil and Recent material deposited in Brazilian and foreign collections, public and private. The tribe is represented in the Brazilian coast by two genera: Eratoidea Weinkauff, 1879 and Marginella Lamarck, 1799. The species of Eratoidea were referred to Dentimargo Cossmann, 1899, that has been confused with Stazzania Sacco, 1890. Yet, it was verified that Dentimargo is a fossil genus restricted to the Parisian Eocene, characterized by the high degree of bifurcation on the columelar plicactions a the presence of a fifth columelar plication, while Stazzania, also a fossil genus, is restricted to the Italian Miocene and characterized by a slight bifurcation on the columelar plications and the absence of the fifth columelar plication. Eratoidea can be traced, through its fossil record, since the North American middle Eocene, and is still have living representatives. The high morpho-conchological variability of its species has led other reviewers that the group could be split in two genera, corresponding to the extremes of this variation. But since there are many intermediate species between the extremes and there are no distinctive characters to separate the groups, Eratoidea is considered as the valid genus for the group. ln Brazil it is represented by five species: E. scalaris (Jousseaume, 1875), Eratoidea sp. 1, Eratoidea sp. 2, Eratoidea sp. 3 and E. lasallei (Talavera & Princz, 1985). Marginella was used to encompass almost all the Marginellidae family. This has hindered its precise definition, but recently after many revisions, its is possible to properly identify its species. ln Brazilian waters it is represented by Marginella cloveri Rios & Matthews, 1972, that is also the only known species in the west Atlantic.