Description of Alitta yarae sp. nov. (Annelida, Nereididae): a new oligo/mesohaline species from southern Brazil

A new species of annelid, Alitta yarae sp. nov., is described from material collected in southern Brazil. This species was collected mostly from fishing buoys but also in muddy substrates of the following estuaries: Parana Estuary Complex, Guaratuba, and Babitonga Bay. Alitta yarae sp. nov. belongs to a group of species with pennant-shaped posterior dorsal ligules. The most similar species of this group is A. succinea, which shares glandular structures from posterior dorsal ligules on lower edge only and having yellow-amber mandibles. However, the two species differ in the extension of the bare space between areas VI and VII-VIII, which is reduced in A. yarae sp. nov. and wider in A. succinea (respectively shorter than or equal to the palpophore), and the paragnath arrangement. Molecular analysis recovered similar to 20% genetic distance from the closest species A. succinea and no pattern of segregation among the estuaries studied. Finally, both the morphological and the molecular analyses strongly support the designation of a new species. http://zoobank.org/urn:lsid:zoobank.org:act:2575CF46-57C9-47AE-A4C1-235189F6C107