Four species of the callichirid ghost shrimp genus Corallianassa Manning, 1987 are recognised in Hawaii based on evidence from morphology and the CO1 gene. Corallianassa borradailei (De Man, 1928) is ...a widespread Indo-West Pacific species now confirmed for Hawaii. Corallianassa lanceolata Edmondson, 1944 is an endemic species similar to C. assimilis (De Man, 1928) from Indonesia and Guam. Corallianassa martensi (Miers, 1884) is also a widespread Indo-West Pacific species. Callianassa (Callichirus) winslowi Edmondson, 1944 (Hawaii), Callianassa (Callichirus) nakasonei Sakai, 1967 (Japan) and Callianassa haswelli Poore & Griffin, 1979 (Australia) are treated as junior subjective synonyms of C. martensi. Callianassa (Callichirus) oahuensis Edmondson, 1944, long treated as a junior synonym of C. borradailei, is revived as a valid species of Corallianassa. The four species differ in the shape and dorsal setae of the telson, the extent of the carina along the upper margin of the major cheliped palm, the attitude of the rostrum, and the shape of the maxilliped 3.
The previously published ultrastructure of Aegla spermatozoa contributed to the phylogenetics of this unique taxon. The present study describes the spermatozoa of two additional aeglids, Aegla parana ...and A. quilombola. The spermatozoa consist of two hemispheres of the approximate same size and a bilayered acrosomal vesicle; both characteristics of the genus Aegla. The similarity of spermatozoa ultrastructure observed between A. parana and A. quilombola and the endemic Australian anomuran, Lomis hirta (Lomidae) reflects a sister group relationship, even though both are from different regions of the world and different environments today. Aeglid spermatozoa share the same organization with Lomis including the two equal size hemispheres separated by a membrane also two layers in the acrosomal vesicle with the external layer being surrounded by another membrane. The number of spermatozoa microtubular arms is unclear in Aegla, however, they are present in both the nucleus and cytoplasm. This observation does not agree with the presence of spermatozoa arms only in the nucleus, as an exclusive character for Aegla, as proposed previously. The presence of lipid-droplets and peroxisomes was observed only in the spermatozoa of A. quilombola. The greatly reduced number of spermatozoa observed in all specimens analyzed raises concerns about the conservation of several threatened species. In addition, the absence of any spermatophores seems to be a characteristic of the Aeglidae to date.
•Ultrastructure of spermatozoa is useful for Decapoda phylogeny.•Aegla sp. and Lomis hirta have similar spermatozoa within Anomura supporting the phylogeny position as a sister group.•Lipid droplets and peroxisomes were observed only in Aegla quilombola.•Small number of spermatozoa when compared to other freshwater decapod crustaceans.•Absence of spermatophore.
Recent studies based on morphological and molecular data provide a new perspective concerning taxonomic aspects of the brachyuran family Mithracidae. These studies proposed a series of nominal ...changes and indicated that the family is actually represented by a different number and representatives of genera than previously thought. Here, we provide a comparative description of the ultrastructure of spermatozoa and spermatophores of some species of Mithracidae in a phylogenetic context. The ultrastructure of the spermatozoa and spermatophore was observed by scanning and transmission electron microscopy. The most informative morphological characters analysed were thickness of the operculum, shape of the perforatorial chamber and shape and thickness of the inner acrosomal zone. As a framework, we used a topology based on a phylogenetic analysis using mitochondrial data obtained here and from previous studies. Our results indicate that closely related species share a series of morphological characteristics of the spermatozoa. A thick operculum, for example, is a feature observed in species of the genera Amphithrax, Teleophrys, and Omalacantha in contrast to the slender operculum observed in Mithraculus and Mithrax. Amphithrax and Teleophrys have a rhomboid perforatorial chamber, while Mithraculus, Mithrax, and Omalacantha show a wider, deltoid morphology. Furthermore, our results are in agreement with recently proposed taxonomic changes including the separation of the genera Mithrax (previously Damithrax), Amphithrax (previously Mithrax) and Mithraculus, and the synonymy of Mithrax caribbaeus with Mithrax hispidus. Overall, the spermiotaxonomy of these species of Mithracidae represent a novel set of data that corroborates the most recent taxonomic revision of the family and can be used in future taxonomic and phylogenetic studies within this family.
The key characters found to the spermatozoa ultrastructure are the operculum, perforatorial chamber, and inner acrosomal zone. All these structures allowed the separation of the species in different genera and corroborate the molecular phylogeny.
The ultrastructure of the spermatophores and spermatozoa of the Mediterranean hermit crab Pagurus excavatus are described, using transmission electron microscopy. The size of the different parts of ...the spermatophore and spermatozoa are given and their ultrastructure described and compared to similar data already present in the literature for other hermit crabs. The morphology and ultrastructure of the spermatophore and spermatozoa of P. excavatus are species-specific, clearly distinguishing the species from the others already described. The spermatophore and spermatozoa show some similarities with those produced by other representatives of the genus. In particular, the tripartite spermatophore is divided into two halves by the lateral ridge and, as with the spermatophores produced by other species belonging to the genus Pagurus, it is morphologically very different from any other Paguroidea. The spermatozoa are composed of an ovoidal acrosomal vesicle capped by the operculum; the acrosome has a length:width ratio of approximately 1.75, therefore larger than 1 as reported for all anomurans studied to date. At the base of the acrosomal vesicle, there is the thin cytoplasm, the large nucleus and three arms positioned to form a 120° angle between each other. The present description is an important additional step allowing for better understanding of the relationships among the different hermit crab taxa.
We investigated the morphology of spermatozoa, spermatophores and the anterior vas deferens (AVD) of the gecarcinucid freshwater crab Sundathelphusa philippina. The morphology of the acrosome ...(proportions, structure and arrangement of acrosomal layers) and the spermatophores complies with the known sperm and spermatophore morphology of the brachyuran family Gecarcinucidae. The sperm cells are packed within coenospermic spermatophores that are of a mucous type, lacking a complex spermatophore wall. Spermatophore formation takes place in the distal part of the AVD. The strongly proliferated inner epithelium of the vas deferens releases vesicles via apocrine secretion. These vesicles fuse with the incipient spermatophores that subsequently coalesce, thus forming the coenospermic aggregates that represent the mature spermatophores.
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.
The names Gebiidea and Axiidea, erected by de Saint Laurent (1979), have priority over others for the two infraorders of shrimps previously included in Thalassinidea. Importantly, Thalassinidea are ...not monophyletic and the name should be replaced. Gebiidea and Axiidea, besides having priority and describing two monophyletic taxa, are now in common use (130 citations) and are more stable than alternative schemes proposed by Sakai (2005 and later). The history of the names of higher taxa applied to these groups is reviewed, and all family-group taxa listed.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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 separeted 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.
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