Description of Leptuca capillosa sp. nov., a new fiddler crab species (Crustacea, Decapoda, Ocypodidae) from the continental coast of Ecuador

A new species of fiddler crab, Leptuca capillosa sp. nov., is described based on two preserved specimens from the U.S. National Museum of Natural History (Smithsonian) as the holotype and paratype. In addition, specimens (N = 46) collected at eight locations along the Pacific cost of Ecuador were used for an anatomical description and a biometric study. Biometric relationships among major anatomical features are described by linear-regression algorithms with coefficients of correlation and determination. From a previously published DNA analysis of the new species, L. capillosa sp. nov. is related to other Leptuca species in the Gelasiminae subfamily of ocypodid crabs. The new species shares an evolutionary clade with Leptuca festae (Nobili, 1902), L. limicola (Crane, 1941) and L. oerstedi (Rathbun 1904). Currently, 14 species of fiddler crabs from the genus Leptuca inhabit various intertidal niches along the coast of Ecuador. A diagnostic morphological characteristic distinguishing L. capillosa sp. nov. from the others is the bilateral occurrence of oval patches of pile/pubescence on the anterior dorsolateral hepatic surface of the carapace. The new species inhabits sparsely vegetated, intertidal mud flats washed with brackish (4–9 ‰) estuary water. So far, L. capillosa sp. nov. has been collected only in Ecuador between the Rio Mataje and the Golfo de Guayaquil.