2006 Volume Special2006 Issue 6 Pages 121-131
Male gonopores on most hermit crabs (Paguroidea) occur as circular or oval apertures on the coxae of the fifth pereopods , are flush with the surrounding coxal segment, may be covered by a membrane or a calcified operculum, and are normally associated with numerous complex setae. In many male paguroids of the families Paguridae and Coenobitidae, elongate tubelike extensions called sexual tubes are found on the coxae. The sexual tubes of C. perlatus and C. clypeatus of the Coenobitidae are here investigated at the histological and SEM level for the first time. Coenobita clypeatus has two short, squarish, equal/subequal extensions of the coxae with the densely hirsute gonopore directed ventrally. In contrast, C. perlatus has large, unequal, tubular extensions of the coxae, directed posteriorly, and with the hirsute gonopores terminally on the tubes. The right sexual tube is the longest, and curves across the mid-line of the body. The left sexual tube is much shorter and extends posteriorly from the coxa. In both, the sexual tubes have various coarse setae of several different morphotypes. Histological sectioning reveals a vas deferens terminating at the gonopore, and that sexual tubes are as heavily calcified and muscular as the coxal segments they emanate from. This differs markedly from previously investigated sexual tubes in other paguroids.
