Unravelling the convoluted nomenclature of Marphysa simplex (Annelida, Eunicidae) with the proposal of a new name and the re-description of species

Abstract

Marphysa simplex is a name that three species bear within the same genus, but each has a different authority and morphological characteristics. This homonymy condition leads to taxonomic confusion and the finite designation of name-bearing is imperative. The current study focuses on two species identified as M. simplex Crossland, 1903 and M. simplex Treadwell, 1922 and a third one, recently considered a secondary homonymy, M. simplex (Langerhans, 1884), is also assessed. The available type specimens were examined and re-described in detail using updated characters and the original descriptions. Marphysa simplex (Langerhans, 1884) is herein judged as an indeterminable species. Marphysa simplex Crossland, 1903 is confirmed as a junior synonym of M. teretiuscula (Schmarda, 1861a) because the differences are minimal. Moreover, M. teretiuscula has characteristics similar to Group B2 (Sanguinea-group; only compound spinigers), instead of the Teretiuscula-group (compound spinigers in the anterior region, subacicular limbate in all chaetigers). On the other hand, M. simplex Treadwell, 1922 is a junior primary homonym of Crossland’s species replaced by M. fijiensisnom. nov. with the chaetal arrangement similar to Group A (limbate chaetae only). In conclusion, the name M. simplex is now unacceptable. The hypothesis on species group only with limbate chaetae and the redescription on M. teretiuscula is also given.

Four new species of Marphysa (Annelida, Eunicida, Eunicidae) from the east coast of Peninsular Malaysia

“…According to Fauchald (1970) and Glasby and Hutchings (2010) , Marphysa can be divided into five informal groups (Groups A–E) depending on their type of chaetae. Group A (Mossambica) without compound chaetae, Group B (Sanguinea) with only compound spinigers present, Group C (Aenea) with only compound falcigers present, Group D (Belli) with both spinigers and falcigers present, and Group E (Teretiuscula; renamed Gravelyi by Molina-Acevedo and Idris 2021 ) with only compound spinigers and subacicular chaetae in anterior parapodia and limbate chaetae throughout.…”