A New Genus and Species of Marine Symbiotic Shrimp (Crustacea: Decapoda: Palaemonidae) from New Caledonia

A single specimen of a new genus and species of marine palaemonid shrimp was collected from the outer slope of the barrier reef of Koumac, northwest New Caledonia. The new shrimp is remarkable due to its unique series of diagnostic characters, i.e., the presence of compressed supraorbital teeth, a well-developed orbital cavity, closely set antennal and hepatic teeth on the carapace, swollen eyestalks, fully reduced endites on the maxilla, an anteriorly produced lobe on the fourth thoracic sternite, relatively small second chelipeds, and strongly biunguiculate ambulatory dactyli. This specimen occupies an isolated phylogenetic position among the symbiotic palaemonid shrimp analyzed, only demonstrating a feeble morphological inclination towards the “gnathophyllid” section of these. However, neither the main diagnostic characters nor genetic data allow for further clarification of a closer relationship between this new shrimp and any currently known palaemonid genus as of yet. The new genus and species is described in this report, and its phylogenetic position is discussed based on molecular and morphological characters.