Further records of four frog crabs (Brachyura: Raninoidea) of the south-southwest Gulf of Mexico with comments on biogeographical affinities

Frog crabs are marine brachyurans predominantly tropical-subtropical adapted for inhabiting soft sandy bottoms across a wide bathymetric range. In the Gulf of Mexico, seven species of the superfamily Raninoidea have been reported. This study documents further records of 495 frog crabs collected in the south-southwest Gulf of Mexico, belonging to Raninoides louisianensis Rathbun, 1933 (88.1%), Raninoides lamarcki A. Milne-Edwards and Bouvier, 1923 (10.3%), Lysirude nitidus (A. Milne-Edwards, 1880) (1.2%), and Raninoides laevis (Latreille, 1825) (0.4%). The updated records of Raninoidea species from the Gulf of Mexico (based on literature review and results from the present study) extend the geographical distribution of R. louisianensis to the entire Gulf of Mexico. These records indicate that the south-southwest and east-southeast geographic sectors (both in the tropical portion of the Gulf of Mexico) have the highest number of species (6); further, the lower bathymetric limit for R. louisianensis and R. lamarcki is extended. A cluster analysis based on presence/absence data using the Jaccard similarity coefficient provided additional support indicating that the eight geographic sectors of the Gulf of Mexico were closely related (≥0.6) in terms of species composition.