A new species of Tetragoniceps Brady, 1880 (Copepoda, Harpacticoida, Tetragonicipitidae) from an anchialine cave in Bermuda, with an updated key to the species of the genus

Tetragoniceps bermudensis sp. nov. (Copepoda, Harpacticoida, Tetragonicipitidae) is described based on an ovigerous female collected from Roadside Cave, a tidally influenced anchialine cavern in Bermuda. The new taxon represents the 16 th recorded species of Tetragoniceps Brady, 1880.

It can be distinguished from congeneric species by the length: width ratio of the caudal rami (approximately 10 times longer than wide), its cephalothorax with a smooth dorsal surface, and the diagnostic setal formula of its pereiopods 1–5. Tetragoniceps bermudensis sp. nov. is the first record of Tetragoniceps from Bermuda and the first known anchialine species in the genus globally. Based on our description of the new species, we provide a revised key to the species of Tetragoniceps.

In addition, we include an updated table of salient morphological characters for the females of the genus, providing grounds for a preliminary analysis of the phylogenetic relationships of its constituent species.