A New Varunid Subfamily (Decapoda, Brachyura, Grapsoidea, Varunidae) for Crabs From European and West African Waters, With the Description of Two New Genera and Two New Species.

The subfamily Asthenognathinae is currently composed of a single genus, Stimpson, 1858, with three species, Stimpson, 1858, Rathbun, 1909 (both from the Indo-West Pacific), and Monod, 1933 (European and West Tropical African waters). All species are difficult to collect due to their small size and symbiotic lifestyle with fossorial organisms. The examination of specimens of from European and West African waters deposited in scientific collections shows significant morphological and molecular differences with the Indo-West Pacific species, which makes the creation of a new subfamily (Schubartinae n. subf.) and two new genera necessary. The identity of the only species found along the East Atlantic and Mediterranean waters, is clarified, and a new genus, n. gen., is established for this species, (Monod, 1933) n. gen., n. comb. This study also describes another new genus, n. gen., based on morphological differences and genetic data. These two new genera can be distinguished from by the carapace proportions and differences in the structures of the male pleonal somites, pereiopods and endostome. In addition, two new species distributed in Guinea-Bissau and Mauritania, n. gen., sp. nov., and n. gen., n. sp., are described. A key for species of the subfamilies Asthenognathinae and Schubartinae n.subf. is provided.