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

Abstract

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.