Morphology of the first zoeal stages of eleven Sesarmidae (Crustacea,Brachyura, Thoracotremata) from the Indo-West Pacific,with a summary of familial larval characters

Summary

The first zoeal stages of eleven species of Sesarmidae from the Indo-West Pacific were obtained from ovigerous females. Those of Labuanium scandens, L. rotundatum, L. trapezoideum, L. politum, Metasesarma aubryi, Pseudosesarma crassimanum, Stelgistra stormi, and Sesarmops impressum, are described for the first time, while the first zoeal stages of Clistocoeloma merguiense, Metasesarma obesum and Sesarmops intermedium are re-described. Larval characters of all these species are compared with previously described ones for the family and morphological features are re-evaluated. Minute spines on the telson of the zoeae are described as a new larval character in Sesarmidae and their presence or absence in other grapsoid groups is discussed. The results demonstrate that a recurrent combination of reliable larval characters distinguishes zoeae and megalopae of the examined sesarmids from the rest of the Grapsoidea. This appears to be consistent with recent studies that redefine the Sesarmidae.     

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.     

Metamorphosis season from megalopa to the first crab stage in snow crab Chionoecetes opilio and red snow crab C. japonicus (Crustacea,Decapoda, Majoidea) in the Sea of Japan,estimated from captive culture

ABSTRACT

Metamorphosis season of megalopae to the first crab stage in snow crab Chionoecetes opilio and red snow crab C. japonicus was inferred by culturing wild-born megalopae collected from the Sea of Japan. Metamorphosis occurred from late June to late July (mainly in July) in snow crab, and from early July to early October (mainly from August to September) in red snow crab. The number of days required from the time of collection to metamorphosis was less than the intermoult period previously reported for snow crab megalopae. However, the developmental period of the megalopae was estimated as substantially longer in red snow crab than in snow crab. Previous studies have shown that the hatching season and the period of the zoeal stage in both two species are similar. These results suggest that a different metamorphosis season between the two species would be due to a difference in their megalopal intermoult period.     

The zoeal stages and megalopa of Portunus rubromarginatus (Lanchester) (Decapoda: Portnnidae), reared in the laboratory

The present state of knowledge concerning Portunus larvae isreviewed, and the three zoeal and the megalopa stages of P.rubromarginatus are described and figured. Details of appendagesetation are tabulated. This species is unusual amongst knownPortunus spp. in having only three zoeal stages and, like otherPortunus spp. but in contrast with other Portuninae, it has4 + 4, or 4 + 1 + 4, setae on the posterior telson border. When compared with larvae of the five other Indo-West PacificPortunus species whose larvae are known P. rubromarginatus zoeaeare readily distinguished from all, except P. hastatoides, usingthe key features given by Kurata (1975). Comparison was madebetween first zoeae of these two species, and also of P. pelagicusand P. sanguinolentus, using larvae reared by the authors. Itwas found telson characters alone allow distinction betweenlarvae of these four species. These characters are tabulated. P. rubromarginatus megalopae differ from those known for congenitorsin having a large spine on the uchium of the first pereiopod,but not on the carpus, and in having relatively very small sternalcornuae. Several of these features disagree with those previously thoughtto characterise larval Portuninae or Portunus species.     

Larval descriptions of the family Porcellanidae: A worldwide annotated compilation of the literature (Crustacea,Decapoda)

For most of the family Porcellanidae, which comprises 283 species, larval development remains to be described. Full development has been only described for 52 species, while part of the larval cycle has been described for 45 species. The importance of knowing the complete larval development of a species goes beyond allowing the identification of larval specimens collected in the plankton. Morphological larval data also constitute a support to cladistic techniques used in the establishment of the phylogenetic status (see Hiller et al. 2006, Marco-Herrero et al. 2013). Nevertheless, the literature on the larval development of this family is old and widely dispersed and in many cases it is difficult to collect the available information on a particular taxon. Towards the aim of facilitating future research, all information available on the larval development of porcellanids has been compiled. Following the taxonomic checklist of Porcellanidae proposed by Osawa and McLaughlin (2010), a checklist has been prepared that reflects the current knowledge about larval development of the group including larval stages and the method used to obtain the larvae, together with references. Those species for which the recognised names have been changed according to Osawa and McLaughlin (2010) are indicated.     

Larval development of Hexapanopeus caribbaeus (Stimpson, 1871) (Crustacea, Decapoda, Xanthoidea, Panopeidae) reared under laboratory conditions

The genus Hexapanopeus Rathbun, 1898 contains eight species,of which three are found in the Brazilian coast. The larvaldevelopment of two of these species has already been studiedin the laboratory. This article describes in detail the morphologyof the complete larval stages of Hexapanopeus caribbaeus rearedunder laboratory conditions, and the morphology is comparedwith that of the larvae of the other species of the same genus.     

The larvae of the spider crab Pisoides bidentatus (A. Milne-Edwards, 1873) (Decapoda: Majoidea: Pisidae) reared under laboratory conditions

Larval development of the spider crab, Pisoides bidentatus (A.Milne-Edwards, 1873) (Decapoda: Majoidea: Pisidae), inhabitingthe Russian waters of the Sea of Japan is described and illustratedfor the first time from larvae reared in the laboratory. Thedevelopment included two zoea and one megalopa, thus followingthe typical pattern in the Majoidea. At a temperature of 20–22°Clarval development of P. bidentatus took from 9 to 13 days.The comparative analysis revealed that the larvae of two Pisoidesspecies differ in numerous characters whereas zoea of P. bidentatusand Pugettia quadridens belonging to different families arenearly identical. According the larval characters, P. bidentatusand P. quadridens should be assigned to one genus. The larvaldata lend the support to revision the taxonomic position ofP. bidentatus.     

Morphological features of the larvae of spider crab <Emphasis Type="Italic">Pugettia quadridens</Emphasis> (Decapoda: Majidae) from the Northwestern Sea of Japan

The entire cycle of larval development of the spider crab Pugettia quadridens (de Haan, 1850) (Decapoda: Majidae), widespread in Peter the Great Bay (Sea of Japan) is studied under the laboratory conditions. The development cycle of this species comprises prezoea, zoea I, zoea II, and megalopa. At a temperature of 18–20° C larval development took from 11 to 15 days. Zoea II is described in detail for the first time. Many morphological characters are found distinguishing zoea and megalopa of P. Quadridens in Russian waters from the larvae of this species in Japanese and Korean waters. Some characters of larvae are similar in P. Quadridens and the related species of the genus Pugettia. The larvae of P. Quadridens occur in the plankton of Vostok Bay from late June to late October with a density up to 5 ind/m³ at a surface water temperature of 13–21°C. They are easily distinguished from the other brachyuran larvae of this region by the absence of lateral spines on the carapace.Original Russian Text Copyright © 2004 by Biologiya Morya, Kornienko, Korn.     

Larval stages of Brachynotus atlanticus Forest, 1957 (Crustacea: Decapoda: Grapsidae) reared under laboratory conditions

The complete larval development of the Eastern Atlantic grapsidcrab, Brachynotus atlanticus, was obtained in the laboratory.Five zoeal stages, the megalopa and the first crab stage aredescribed and illustrated. Under laboratory conditions at 23°Cthe first crab appeared on the 25th day. This is the first speciesof the genus for which the complete larval development is known.Larval features are compared with those of other members ofthe subfamily Varuninae.     

Comparative morphology of larvae of coastal crabs (Crustacea: Decapoda: Varunidae)

The larval development of three crabs of the Varunidae family, (Hemigrapsus sanguineus, H. penicillatus, and H. longitarsis), widely spread in Russian waters of the Sea of Japan, were studied under laboratory conditions. At a temperature of 20–22°C and a salinity of 32‰ about 30% of larvae a complete developmental cycle, including five zoeal stages and megalopa, took from 22 to 30 days. All larval stages are illustrated and described in detail. Zoea I and zoea II of the studied crabs are not distinguishable. Zoea III–V of these species differ in the number of dorsomedial setae on the abdominal somite I and in the number of setae on the posterodorsal arch. The megalopae of three Hemigrapsus species possess a different number of segments, aesthetascs and setae on the antennular exopod. In spite of the great similarity of larvae of genera Hemigrapsus and Eriocheir, the latter possesses a number of distinctive features in all developmental stages, supporting the separation of these genera.     

Xanthidae MacLeay, 1838 (Decapoda: Brachyura: Xanthoidea) systematics: A multi-gene approach with support from adult and zoeal morphology

Currently, 13 subfamilies are recognised in the brachyuran family Xanthidae: Actaeinae, Antrocarcininae, Chlorodiellinae, Cymoinae, Etisinae, Euxanthinae, Kraussiinae, Liomerinae, Polydectinae, Speocarcininae, Xanthinae, Zalasiinae and Zosiminae. This classification has been based on shared adult features like a transversely ovate carapace, well defined dorsal carapace regions, usually with lateral dentition, stout chelipeds and relatively short ambulatory legs. Such characters are now considered to be convergent. Consequently a number of higher xanthid taxa may be artifical and not monophyletic. A broad sample of 147 xanthid species representing 75 out of 124 genera from all 13 xanthid subfamilies were sampled in a multi-gene analysis. Four markers (three mitochondrial and one nuclear) were used and yielded a tree with ca. 30 xanthid clades. Monophyletic support was demonstrated for the Antrocarcininae (although substantially redefined), Cymoinae, and Polydectinae. Almost every other subfamily was para- or polyphyletic. Furthermore, the two other families of the Xanthoidea, Pseudorhombilidae and Panopeidae, were found nested within the Xanthidae. The molecular results were consistent with phylogenetic relationships implied by a suite of novel and/or neglected “ventral” adult characters including sternal characters, position of genital openings and morphology of the first zoea, instead of “dorsal” characters traditionally used to infer xanthid relationships.     

The larval development of Petrolisthes politus (Gray, 1831) (Crustacea: Decapoda: Porcellanidae) under laboratory conditions

The complete larval development of the shallow-water Caribbean porcellanid crab, Petrolisthes politus (Gray, 1831), is described and illustrated from specimens reared in the laboratory. Petrolisthes politus hatches as a prezoea, which persist for less than 90 minutes, and then molts through two subsequent zoeal stages, which are completed in 6 to 7 and 14 to 16 days, respectively, before the megalopal stage is reached. From a total of about 2000 zoeae that were cultured, only two reached the megalopal stage. The two megalopae survived for up to 5 days but did not molt to the first crab stage. The zoeae of P. politus are compared with those of Petrolisthes rufescens (Heller, 1861), Petrolisthes lamarckii (Leach, 1820), Petrolisthes carinipes (Heller, 1861), Petrolisthes coccineus (Owen 1839) and Petrolisthes pubescens (Stimpson, 1858), which were hitherto the only species having bifid lateral spines on the telson of the first zoeal stage.