Occurrence of two sympatric species of Palaemonidae and Hippolytidae (Decapoda, Caridea) in a coastal ecosystem in western Mexico.

One species of Hippolytidae, Hippolyte californiensis Holmes, 1895, and one species of Palaemonidae, Periclimenes infraspinis (Rathbun, 1902), were collected in a single sample among sea grass in the northern Gulf of California, Mexico. Hippolyte californiensis is partly illustrated and compared to the descriptions available in the literature, noting minor differences with material from California where it was originally described. Diagnostic characters of P. infraspinis are also illustrated. Sex proportion and size distribution indicate a higher incidence of females (male : female ratio, 1 : 2.59), smaller size in males, a strong incidence of ovigerous females (31%), and a brood clutch of 82-200 embryos in P. infraspinis. In H. californiensis, males were more abundant (1.41 : 1), the incidence of ovigerous females was low (15%), and females carried 51-115 embryos. In both species, males, females, and ovigerous females were significantly different in size. These two species have not been reported as sympatric. [ABSTRACT FROM AUTHOR]