Spermatophore morphology and spermatozoal ultrastructure of the recently described hermit crab, Strigopagurus boreonotus Forest, 1995 (Decapoda, Anomura, Diogenidae)

Volume: 18Start Page: 547End Page: 55

17. Ultrastructure and phylogeny of the spermatozoa of the infraorders Thalassinidea and Anomura (Decapoda, Crustacea)

Volume: 166Start Page: 251End Page: 26

Morphologie du spermatophore et ultrastructure du spermatozoïde du bernard-l'hermite récemment décrit, <i>Strigopagurus boreonotus</i> Forest, 1995 (Decapoda, Anomura, Diogenidae)

La morphologie du spermatophore et l&#39;ultrastructure du spermatozoïde du bernard-l&#39;hermite Diogenidae, Strigopagurus boreonotus, sont décrites et comparées avec celles des autres genres de Diogenidae précédemment étudiés. Le spermatophore montre des similarités avec ceux décrits dans les genres Calcinus et Dardanus. Le spermatozoïde a une morphologie générale qui rappelle les espèces du genre Clibanarius et surtout du genre Calcinus, tout en montrant un ensemble original de caractères spermatologiques trouvés jusqu&#39;ici seulement chez Strigopagurus.The spermatophore morphology and spermatozoal ultrastructure of the diogenid hermit crab, Strigopagurus boreonotus, is described and compared with that of previously investigated diogenid genera. The spermatophores show similarities with those described for the genera Calcinus and Dardanus. The spermatozoa have an overall morphology which is reminiscent of representatives in the genus Clibanarius, above all, the genus Calcinus; while still retaining a particular suite of spermatozoal characters so far unique to Strigopagurus.</p

Carcinization in the Anomura – fact or fiction? II. Evidence from larval, megalopal and early juvenile morphology

In this second of a two-part series, carcinization in the Anomura has been reviewed from early juvenile, megalopal, and larval perspectives. Data from megalopal and early juvenile development in ten genera of the Lithodidae have provided unequivocal evidence that earlier hypotheses regarding evolution of the king crab pleon were erroneous. A pattern of sundering, and decalcification has been traced from the megalopal stage through several early crabs stages in species of Lithodes and Paralomis, with supplemental evidence from species in eight other genera. Of major significance has been the attention directed to the marginal plates of the second pleomere, which when separated in lithodids are not homologous with the adult so-called “marginal plates” of the following three tergites. Auxiliary megalopal and early juvenile lithodid data, as well as equivalent data from other paguroids, support the evolutionary direction indicated by lithodid pleonal plate development. Therefore, while carcinization, or development of a crab-like body form, has occurred in the Lithodidae, it has not proceeded from a hermit crab ancestor. Rather the data suggest the reverse, thus effectively refuting the “hermit to king” myth. Brief reviews of data available from the Lomisidae and Porcellanidae support the Proposition of independent anomuran carcinization events in these taxa as well. Results of cladistic analysis of megalopal and juvenile data, although somewhat unconventional, do not support the claim of a sister-group relation of the lithodid genera Lithodes and Paralithodes with the pagurid genus Pagurus. Attempts to subject larval phase data to similar analysis were thwarted by the tendency in paguroids, including lithodids, for lecithotrophic development. Additionally, presumed initial and terminal stage deletions disallow the ontogenetic stage homologies required for meaningful phylogenetic results

Spermatozoal ultrastructure in the spiny lobster Jasus novaehollandiae Holthuis, 1963 (Palinuridae, Palinura, Decapoda)

The spermatozoal ultrastructure of the spiny lobster Jasus novaehollandiae is most similar to that in other investigated palinurans and, in particular, to the spermatozoa of Panulirus species. Shared characters include the globular nucleus penetrated by the bases of three or more microtubular arms; an anteriorly situated cytoplasmic zone with mitochondria and conspicuous lamellar bodies; a complex, four-zoned acrosomal vesicle (however, lacking the crystalline region present in Panulirus) with a homogeneous region; a scroll region; a flocculent region; and a region of periacrosomal material that forms finger-like involutions into the flocculent region. The related scyllarid slipper lobsters (Scyllarus and Thenus) possess spermatozoa with acrosome morphology similar to that of Jasus, but the sperm is generally more flattened, numerous radiating acrosome fins are present, and the microtubular arms (in Scyllarus) are cytoplasmic in origin and not nuclear. Sperm morphology provides preliminary evidence in support of the hypothesis of two independent lines of evolution in the Palinuridae but investigation into additional taxa within this group is required. J. Morphol. 236:117-126, 1998. © 1998 Wiley-Liss, Inc

Ultrastructure of the mature spermatozoon of the king crab Lithodes maja (Lithodidae, anomura, decapoda): Further confirmation of a lithodid-pagurid relationship

Ultrastructure of the spermatophore and spermatozoon of the king crab Lithodes maja is described and illustrated. The spermatophore is a pedunculate structure of which the major components are the sperm-filled ampulla, stalk, pedestal, and a smaller accessory ampulla at the base of the main ampulla. Each spermatozoon features a subspherical, concentrically zoned acrosomal vesicle, capped by a centrally perforate operculum and posteriorly embedded in the cytoplasm, and a large globular nucleus. Three microtubular arms emerge from the cytoplasm below the acrosomal vesicle. The spermatophores and spermatozoa share many features with those of their nearest postulated relatives - members of the Paguridae (the genus Pagurus in particular). Spermatophore characters that link L. maja with pagurids are the presence of the accessory ampulla (synapomorphy, also with the parapagurids) and the homogeneous granular nature of the spermatophore wall. Sperm characters include the simple concentric zonation of the acrosomal vesicle, the shape and differentiation of the operculum (synapomorphic with Paguridae), the electron-dense plume in the base of the acrosomal chamber (synapomorphy with Pagurus), and absence of microvillar projections in this chamber. Several features in which L. maja differs from species in the genus Pagurus include the central perforation in the operculum, the absence of reticulated acrosome zones, and indications of an irregular flange in some planes of the acrosomal vesicle (possible autapomorphy)

Comparative ultrastructure of the spermatozoa of the Majoidea (Crustacea, Decapoda, Brachyura) with new data on six species in five genera

Comparative ultrastructure of majoid spermatozoa belonging to 23 species, in 19 genera and five families, is considered, with new data on Schizophrys aspera; S. rufescens (Majidae, Majinae); Camposcia retusa (Inachidae); Pyromaia tuberculata (Inachoididae); and Huenia heraldica and Menaethius monoceros (Epialtidae, Epialtinae). The oregoniid Chionoecetes opilio, and inachids Cyrtomaia furici, Platymaia rebierei, Macropodia longirostris and Inachus phalangium, possibly with Camposcia retusa, but not Podochela riisei, appear to form a group. Within the inachids, Macropodia and Inachus are especially close. A domed central acrosome zone, seen in most inachid sperm, in majines (both Schizophrys species), in pisines (Oxypleurodon orbiculatus and O. stuckiae) and epialtines (Huenia heraldica and Menaethius monoceros), appears to be an autapomorphy of these majoids. A peripheral acrosome zone is seen in the inachid Grypacheus hyalinus, two inachoidids (P. tuberculata and Stenorhynchus seticornis) and the majid Maja squinado. Pyromaia tuberculata differs from other inachoidids in having a slightly dome-shaped operculum. The mithracine Macrocoeloma trispinosum (Majidae) sperm more closely resembles Inachoididae, than Inachidae. Spermatologically, the family Majidae and the subfamily Majinae are not homogeneous. Spermatozoal ultrastructure does not support a majoid-hymenosomatid relationship and is equivocal with regard to the placement of Cryptochiridae in either the Thoracotremata or Heterotremata, the prominent operculum strongly differentiates cryptochirids from Majoidea. Acta Zoologic