Description of the world's smallest clawed lobster, a new species of Nephropsis Wood-Mason, 1872 (Decapoda: Astacidea: Nephropidae)

Abstract

Several small specimens of a clawed lobster recently collected off the island of Guadeloupe in the West Indies and originally reported as Nephropsis aculeata Smith, 1881 are found to represent a species new to science. The new species, N. perexigua sp. nov., can be readily separated from N. aculeata by the absence of a dorsal median carina in the abdomen. Nephropsis perexigua sp. nov. actually closely resembles N. pygmaea Chang, Chan & Kumar, 2020 from the West Pacific, but differs in the abdomen being smooth. The shape of the posteromesial plate on the coxa of the pereiopod III is also distinctly different among males of N. perexigua sp. nov., N. aculeata, and N. pygmaea. The large sequence divergence in the barcoding gene COI supports the distinct specific status of the new species. With the carapace length of the largest specimen being 12.1 mm and the smallest ovigerous female only 10.0 mm, N. perexigua sp. nov. is the world's smallest clawed lobster so far known. An updated key to the species of Nephropsis Wood-Mason, 1872 is provided.