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

Abstract

In the present study, the morphology and biometry of the spermatophores of the western Atlantic hermit crab Clibanarius sclopetarius (Herbst, 1796) are described, and the results are placed in the context of the Paguroidea, in particular the Diogenidae. Individuals of C. sclopetarius were sampled from a human-impacted mangrove area of southern Brazil. The male reproductive system was removed, measured and analyzed using stereoscopic, light, transmission-electron and scanning-electron microscopy. This system is composed of lobular testes connected to the vas deferens, and gonopores with membranous coverage. The mature spermatophore consists of a spherical pack that stores sperm. These cells consist of a spherical acrosomal vesicle, an amorphous cytoplasm and a distal nucleus. The results revealed that the gonopores, testis and vas deferens have the expected characteristics of the family Diogenidae, while the non-tripartite morphology of the spermatophores and the sperm follow the patterns found only in the genus Clibanarius, and the presence of the dense perforatorial ring is, to date, unique in the species of the genus, being a possible apomorphic characteristic.KEY WORDS: Diogenidae · Reproduction · Spermatophores · Sperm · Spermiotaxonomy Resale or republication not permitted without written consent of the publisherAquat Biol 12: [271][272][273][274][275][276][277][278][279][280] 2011 and a variable number of arms. Among the Anomura, the acrosomal vesicle can be oblong (Jamieson 1991) or spherical (Tudge 1992, Tudge & Scheltinga 2002 in shape and is covered by a spherical or conical operculum. Moreover, the anterior region of the cytoplasm or of the nucleus bears 3 arms that contain microtubules (Jamieson 1991).The association of the sperm characteristics with other reproductive components (testes, vasa deferentia, and spermatophores) is important to better understand the process of fertilization (Sastry 1983, Uma & Subramoniam 1984, Amadio & Mantelatto 2009). In addition, the great diversity found in the morphologies of the sperm and of the spermatophore, with characteristics that are particular to members of different groups, make these structures taxonomically specific (Tudge 1991, Subramoniam 1993; thus, together with other taxonomic criteria, they can also be used to elucidate taxonomic and phylogenetic questions (Scelzo et al. 2004, Mantelatto et al. 2009, Tudge 2009).In the superfamily Paguroidea, which contains the hermit crabs, the spermatophores are complex and tripartite structures, consisting of an ampulla, a stalk, and a pedestal (Tudge 1991, Krol et al. 1992, Subramoniam 1993, Scelzo et al. 2004, Tirelli et al. 2007, Mantelatto et al. 2009). Tripartite spermatophores with a small and spherical ampulla and a long and thin stalk have been de scribed only for diogenid members (Tudge 1991), but exceptions in this division have been observed in some species of the genus Clibanarius, where the stalk and the pedestal are absent (Uma & Subramoniam 1984, Hess & Bauer 2002.The family Diogenid...

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

“…We only know that in the superfamily Paguro idea, spermatophores are placed externally on the exo skeleton or in the surface of the gastropod shell inhabited by the female (Matthews 1953, Tudge 1991, Hess & Bauer 2002. The positive correlation between the SL measurements and gonopore diameter indicates that the size of the gonopores is directly proportional to the size of the hermit crab, as reported for other diogenid species (Amadio & Mantelatto 2009, Mantelatto et al 2009b, Santos & Mantelatto 2011). This pattern means that an intimate relationship during ontogeny occurs between hermit crab size and reproductive body dimensions.…”

“…However, the gonopores of P. diogenes differ significantly from those of other species with respect to the number of associated setae. Whereas the gonopores of P. diogenes are completely surrounded by setae, the gonopores of some species, such as Calcinus tibicen (Amadio & Mantelatto 2009) and Clibanarius sclopetarius Herbst, 1796 (Santos & Mantelatto 2011), exhibit few or no setae. Other species, such as I. sawayai (Mantelatto et al 2009b), L. loxochelis (Scelzo et al 2004), Clibanarius erythropus Latreille, 1818 (Tirelli et al 2007), and Diogenes pugilator (Manjón-Cabeza & García-Raso 2000), exhibit an intermediate number of gonopore setae, but these are still far fewer than in P. diogenes.…”

“…The genus Clibanarius, besides its proximity to P. diogenes, has species with 2 types of spermatophores. Species such as Clibana rius sclopetarius (Hess & Bauer 2002, Santos & Mantelatto 2011. Other species, such as C. erythropus and C. corallinus, show tripartite spermatophores with small, spherical ampullae and thin, long stalks (Tudge 1991), so the non-tripartite pattern can be considered as a secondary loss in this genus (Santos & Mantelatto 2011).…”

“…However, some continuous characters, such as spermatophore measurements, should not be used to infer relationships or, as proposed by Scelzo et al (2004), as a criterion to characterize and distinguish species, because the dimensions are strongly associated with the individual size and cannot be used alone in phylo genetic comparisons (Amadio & Mantelatto 2009, Santos & Mantelatto 2011. None theless, proportions between spermatophore regions can indicate shape (such as an ovoid or cylindrical am pulla or an ampulla much bigger than the stalk) and can be used to infer phylogenetic relationships.…”

“…Species such as Clibana rius sclopetarius (Hess & Bauer 2002, Santos & Mantelatto 2011. Other species, such as C. erythropus and C. corallinus, show tripartite spermatophores with small, spherical ampullae and thin, long stalks (Tudge 1991), so the non-tripartite pattern can be considered as a secondary loss in this genus (Santos & Mantelatto 2011). Species from the family Coenobitidae, represented by Coenobita compressus H. Milne Edwards, 1837, in the phylogenetic tree, also have different spermatophores, with large spherical ampullae and short thick stalks, showing a robust appearance (Tudge 1991).…”