Three new species of the genus Perinereis (Annelida, Nereididae) from Egyptian coasts.

Abstract

Despite being one of the most common groups of polychaetes on intertidal shores, the genus Perinereis (Nereididae) is comparatively poorly known taxonomically, with confusion still existing due to the lack of comprehensive systematic studies. The systematics of Perinereis species from the intertidal Egyptian coasts of the Red Sea, Gulf of Suez and Suez Canal have been investigated using morphology and the mitochondrial barcoding marker cytochrome oxidase subunit I (COI). New sequence data was obtained for 102 Perinereis specimens and analysis included all publicly available COI data from other Perinereis species. The COI data indicate that monophyly of the P.nuntia species group is doubtful, as specimens identified in this species group from south-eastern Asia and Australia form a monophyletic group exclusive of the three new species described in this study from the Red Sea region. A morphometric character set (26 characters) was used to identify and characterize each specimen in the study. Three distinct morphospecies belonging to the P.nuntia species group were found, each differentiated by the number and type of paragnaths on pharyngeal areas V and VI, relative sizes of parapodial lobes, type of notochaetae and neurochaetae, and form of the neurochaetal falciger blades. The three morphospecies were well supported by COI data: two of the three new species, Perinereissuezensis sp. nov. and Perinereisfayedensis sp. nov., are closely similar to P.nuntia sensu stricto, while the other, Perinereisdamietta sp. nov., is similar to P.heterodonta. The new species are described and illustrated, and bring the number of species in Perinereis to 97. The new species are compared and contrasted to the closely similar P.heterodonta, P.nuntia and other congeners from the region.