Male reproductive apparatus and spermatophore morphology of the hermit crabs Pagurus brevidactylus and P. criniticornis (Anomura, Paguridae)

Abstract

Spermatozoa of most crustacean species are nonmotile and are packed into spermatophores. In Decapoda, spermatophores are highly variable in morphology and can be useful in the solving of taxonomic and systematic questions, especially among the Anomura. In this study, the morphology and morphometry of the spermatophores of the western Atlantic hermit crabs Pagurus brevidactylus and P. criniticornis are described. The abdomen of fresh male specimens was dissected to expose the reproductive system and to extract the spermatophores, which were analyzed by stereoscopic, light, and scanning electron microscopy. The vas deferens can be divided macroscopically in three regions, all of them containing spermatophores. Tripartite spermatophores are composed of an elongated cylindrical main ampulla, a triangular accessory ampulla, a narrow cylindrical peduncle, and a round pedestal. Dimensions of the spermatophore components are positively correlated to the size of the crab. Morphological patterns observed in this study resemble those of other pagurid hermit crabs investigated to date. The morphological character distribution confirms classifications based on adult morphology and molecular analysis.

Spermatophore and spermatozoal ultrastructure of the Mediterranean hermit crabPagurus excavatus(Paguridae: Anomura: Decapoda)

“…In Pagurus species described up to now, the male reproductive system shows the same patterns described for Decapoda and Paguroidea (McLaughlin, 1980, 1983; Krol et al , 1992; Fantucci & Mantelatto, 2011), but they present a great difference in the gross morphology of the vasa deferentia. These last are relatively shorter and straighter (Scelzo et al , 2010; Fantucci & Mantelatto, 2011) than in described Diogenidae, in which ducts are proportionally longer and mostly helicoidal (Scelzo et al , 2004; Tirelli et al , 2006, 2007, 2008; Amadio & Mantelatto, 2009; Mantelatto et al , 2009b). This difference in length may be a consequence of the lack in Paguridae of the two regions responsible for lengthening of spermatophore stalk (Matthews, 1957; Greenwood, 1972).…”

“…In particular, regarding the Paguridae, the ampulla wall and lateral ridge ultrastructure had been previously described only for Pagurus bernhardus (Linneus, 1758), Pagurus hirtimanus (White, 1847) and Pagurus prideaux (Leach, 1815) by Tudge (1999a, b). More recently it had been described in Pagurus exilis (Scelzo et al , 2010) and in Pagurus criniticornis and Pagurus brevidactylus (Fantucci & Mantelatto, 2011). Also the spermatozoa show a great structural and morphological diversity (Subramoniam, 1982; Felgenhauer & Abele, 1991; Tudge, 2009).…”

“…This difference in length may be a consequence of the lack in Paguridae of the two regions responsible for lengthening of spermatophore stalk (Matthews, 1957; Greenwood, 1972). The genital openings of the Pagurus species (Fantucci & Mantelatto, 2011) are simple gonopores, differing from hermit crabs species without sexual tubes in the large number of setae surrounding the gonopore itself. These setae have been supposed to have a sensory function during mating, to provide better adhesion to the female gonopore, and to act as sensors during the transfer of spermatophores to the partner (Manjón-Cabeza & García Raso, 2000; Tudge & Lemaitre, 2004).…”

Reproductive system of the male hermit crab ­Clibanarius sclopetarius: gonopore, spermatophore, and spermatozoal morphologies

“…We strongly suggest the establishment of a standard code of measurements in hermit crabs to facilitate comparisons. In addition, and considering that individual body size strongly influences spermatophore size, Fantucci & Mantelatto (2011) suggest that more attention be given to morphology than to size, to avoid possible errors in comparisons.…”

Reproductive apparatus of the male giant hermit crab Petrochirus diogenes (Anomura, Diogenidae): morphology and phylogenetic implications

“…Comparisons of reproductive morphology are a taxonomic tool, providing key characters for species delimitation, solving taxonomic problems and establishing phylogenetic relationships between groups of crustaceans (Mantelatto et al 2009a, Fantucci & Mantelatto 2011. Recently, studies based on electron microscopy have intensified interest in morphological analyses of the re productive structures of decapod crustaceans, especially in males (Manjón-Cabeza & García-Raso 2000, Amadio & Mantelatto 2009).…”