Varying colour pattern, yet genetically similar: Pebble crab Seulocia vittata (Stimpson, 1858) (Brachyura: Leucosiidae) from the southeastern coast of India

Abstract

Five adult specimens of leucosiid crab Seulocia vittata (Stimpson, 1858) were recently collected off the coast of Palk Bay, southern India. Typical morphological examination revealed the presence of two colour patterns: grey and red. Interestingly, molecular analysis based on the barcoding gene cytochrome oxidase sub unit I (COI) revealed that both grey and red colour patterns in S. vittata showed 0% sequence divergence between the specimens. This indicates a situation of reverse cryptic behavior in this crab. Surprisingly, the evolutionary and ecological processes leading to the absence of genetic divergence and variation in morphology (colour pattern) in S. vittata complex remain to be addressed.