The complete larval development of the Mangrove Ocypodid crab Macrophthalmus depressus Ruppell, 1830 (Brachyura: Macrophthalminae) reared in the laboratory

Macrophthalmus depressus larvae were reared in the laboratory using filtered estuarine water of salinity 25±1 ppt and temperature 29–31°C. M. depressus reaches the first crab stage after passing through five zoeal and a megalopa stage requiring 22–23 days. Each stage is described in detail and compared with other known species of the genus.     

Laboratory rearing of the larval stages of Carcinus maenas (L.) [Crustacea: Decapoda]

Summary

Larvae of Carcinus have been reared to the crab stage for the first time in the laboratory. Artemia nauplii were successful as food from Stage II zoeae onwards and Stage I zoeae fed and moulted successfully on the dinoflagellate Prorocentrum. Animal foods smaller than Artemia were not tried, but the larvae or eggs of molluscs, echinoderms or polychaetes would probably be suitable. Entirely algal diets were unsatisfactory for complete development.

On diets of Prorocentrum and Artemia, the overall survival rates to first crab stage were about 30% and the average total development time was 57·7 days. Average duration of each larval stage, in days, was 14·8 (zoea I), 7·9 (zoea II), 9·6 (zoea III), 10·0 (zoea IV) and 15·4 (megalopa).     

Larval and early juvenile development in Paralomis granulosa (Jacquinot) (Decapoda: Anomura: Paguroidea: Lithodidae), with emphasis on abdominal changes in megalopal and crab stages

Morphological variations in the two zoeal stages and megalopa of a lecithotrophic population of Paralomis granulosa (Jacquinot) reared under laboratory conditions are reviewed. Attention is also directed to certain aspects of their development not previously considered. More importantly, the first three juvenile stages are described and illustrated for the first time. Specific consideration is given to the structural changes in the abdominal tergites during the transformation from megalopa to third crab, and ancillary information on abdominal plate development in juvenile stages four and five is provided. Total pleopod loss in both sexes and subsequent reappearance in females is discussed.     

The complete larval development of the crab Pilumnus spinifer (Brachyura: Xanthoidea: Pilumnidae) reared in the laboratory

The complete larval development of the crab Pilumnus spinifer from the western Mediterranean was obtained in the laboratory. All four zoeal stages and the megalopa are described and illustrated. The morphological characters of the larvae of Pilumnus spinifer are compared with those of other known larvae of the genus. The zoeae of P. spinifer show the rostral spine longer than the antennule (excluding aesthetascs); short lateral spines present on the carapace, and the mediolateral processes are present only in abdominal somites 2 and 3. The megalopa is similar to that of other Pilumnidae species. The morphology of the larval stages shows very similar characteristics to that of those of P. hirtellus and P. dasypodus, among the described stages of the family.     

The larval and post-larval development of Gibbs's spider crab,Pisa armata (Latreille) [family Majidae: subfamily Pisinae], reared in the laboratory

Summary

The larvae and first crab stage of the spider crab Pisa armata are described from laboratory reared material. The larval stages are compared with previous accounts and with those of Pisa tetraodon. Larval affinities with other genera of Pisinae are discussed.     

Larval development in Phimochirus roseus (Benedict) (Decapoda: Anomura: Paguridae) reared in the laboratory

The zoeal and megalopal stages of Phimochirus roseus (Benedict, 1892) are described and illustrated from material reared under laboratory conditions. Although the vast majority of zoeae of this species pass through only four larval stages before the moult to megalopa, an occasional fifth stage has been observed. Phimochirus roseus differs in a number of morphological attributes from the only other species of Phimochirus whose larvae have been described. However, their shared features are sufficiently characteristic to confirm the distinctiveness of the genus and its general developmental homogeneity.     

The larval development of the mud shrimp Upogebia yokoyai Makarov, 1938 (Decapoda: Gebiidea: Upogebiidae) reared under laboratory conditions

Larval development of the mud shrimp Upogebia yokoyai Makarov, 1938 Makarov, VV. 1938. Crustacea Anomura. Fauna USSR. 10;3, Moscow, Leningrad: AN SSSR.  [Google Scholar] (Decapoda: Gebiidea: Upogebiidae) is described and illustrated for the first time from material reared in the laboratory. The development includes four zoeal stages and a megalopa. At 20–22°C the megalopa was attained 16 days after hatching. The zoeae of U. yokoyai are distinguishable from those of the sympatric species Upogebia major and Upogebia issaeffi, inhabiting Russian waters of the Sea of Japan, by the presence of two pairs of spines (posterolateral and posterodorsal), each on the fourth and fifth pleonal somites. The megalopa of U. yokoyai differs in the length of the rostral spine, shape of telson and number of antennular aesthetascs.     

Larval development of Clibanarius antillensis Stimpson, 1859 (Crustacea: Anomura: Diogenidae) reared under laboratory conditions: a comparison between Panamanian and Brazilian populations

The larval developmental sequences of Clibanarius antillensis Stimpson from first zoea through to megalopa are compared between laboratory-reared populations from Panama and Brazil. Only four zoeal stages are recorded for the Panamanian population, in contrast to four or five for the Brazilian larvae. Other differences in morphology are discussed and illustrated. Variations resulting from geographic differences and/or differing laboratory conditions raise the question of the validity of phylogenetic hypotheses based on single laboratory rearing events.     

The larval development of Petalomera japonica (Henderson) (Decapoda,Dromiidae) reared in the laboratory

The complete larval development of Petalomera japonica (Henderson) is described, based on laboratory rearing. The species has two zoeal stages and a megalopa. Detailed comparisons are made with other dromiid larvae, particularly those of Petalomera wilsoni.     

Zoeal development of Ethusa microphthalma smith, 1881 (Brachyura,Dorippidae) reared in the laboratory,with a comparison of other dorippid zoeae

The complete zoeal development of a dorippid crab in the subfamily Ethusinae is described for the first time from a known parental female. The ovigerous Ethusa microphthalma was collected in the northern Gulf of Mexico off Louisiana. Larvae passed through four zoeal stages, and the megalopa was reached in 59 days at 20°C and 35 ppt salinity. The larvae differ from those of the few other dorippids for which a zoea is known. Salient distinguishing features include long lateral carapace spines, the presence of six setae on the endopod of the maxillule and maxilla, and a spinose antennal exopod lacking projecting mid-length spines or setae. Zoeal characters are compared to those known for the allied subfamily Dorippinae, and all references to zoeae of the Dorippidae are tabulated.     

Larval development and emigration behaviour during sea-to-land transition of the land hermit crab Coenobita brevimanus Dana, 1852 (Crustacea: Decapoda: Anomura: Coenobitidae) under laboratory conditions

To determine the early life history of the land hermit crab Coenobita brevimanus Dana, 1852, larvae were cultured individually in the laboratory. The zoeal and the megalopal stages are described and illustrated. The larvae developed through four planktonic zoeal stages to the megalopal stage. The major differences in the zoeal characters between C. brevimanus and other described Coenobita species were found in the armature of the pleomeres, whereas the character of pleomeres of C. brevimanus zoeae is the same as that of the coconut crab Birgus latro, a different genus in the same family. Morphological similarity was also found in segmentations of antennules and antennae in megalopae between C. brevimanus and the coconut crab. Megalopae of C. brevimanus were cultured in containers holding seawater and a hard substrate. These crabs migrate from the sea to land after developing a habit of acquiring gastropod shells.     

A synopsis of Martarega White, 1879 (Insecta: Heteroptera: Notonectidae) occurring in the Brazilian Amazonia,with descriptions of three new species

The genus Martarega comprises 15 species and nine of these have been recorded in northern Brazil. Martarega pydanieli sp. nov. from Rondônia, while Martarega nieseri sp. nov. and M. barcelos sp. nov. from Amazonas are described here. Six known species are recorded in the Brazilian Amazonian Region (Amazonas, Pará, Rondônia and Roraima): M. brasiliensis, M. chinai, M. gonostyla, M. membranacea, M. oriximinaensis, and M. uruguayensis. At the outset of this survey the genus Martarega of the Brazilian Amazonian Region held 12 species, but no specimens of M. mcateei, M. hungerfordi, and M. williamsi were collected in the regions sampled. Martarega brasiliensis is newly recorded from Roraima, which comprises the first record of members of this genus in this State. Martarega uruguayensis is newly recorded from Pará and Rondônia, while M. gonostyla from Rondônia. Distinct keys to males and females of Martarega occurring in this region, including these new species, are provided.     

The salinity during larval development affects the dispersion in adults of the tree-climbing crab Aratus pisonii

Adults of the tree-climbing crab Aratus pisonii occur in estuarine regions with a range of salinity of 0–35. However, the larvae cannot complete the development in a wide range of salinities. A study about the effect of salinity on the larval development was conducted in order to infer about adult dispersion and occurrence in a wide range of salinity. Two experiments were conducted: (1) from zoae I to megalopae stage and (2) from megalopa to juvenile stage. Larvae from eight females from Paranaguá Bay, Paraná, Brazil were obtained. After eclosion, for the first experiment, 100 zoea larvae from five females were acclimated, individualized and transferred to small aquariums with five distinct salinity treatments (S0, S5, S15, S25 and S35). For the second experiment, 50 megalopae from three females were individualized in aquariums in the same salinity treatments. Both experiments were conducted in incubator BOD with a constant temperature of 25°C and photoperiod of 12 hours (light/dark). Larvae were fed daily with eggs and naupli newly hatched of Artemia sp. The salinity affected the survival rate during the development in both experiments. Higher survival from zoea I to megalopa stage occurred in salinities 25 and 35 PSU, while from megalopa to juvenile stage in salinities 15 and 25 PSU. In both experiments the larvae did not tolerate low salinities as adults, with total mortality in S0 and S5. Our results suggest that the species have a larval export strategy of zoae larvae to oceanic regions (higher salinities) and megalopae needed to return to estuarine areas with intermediate salinities to complete the development. The occurrence of adults in estuarine areas with low (< 5 PSU) or high (> 25 PSU) salinities most likely occur after the metamorphosis to the juvenile stage by terrestrial dispersion or at the stage of megalopa (marine dispersion) during favourable weather events.     

Comparative population biology of Uca rapax (Smith, 1870) (Brachyura,Ocypodidae) from two subtropical mangrove habitats on the Brazilian coast

The structure of two populations of the fiddler crab Uca rapax in two subtropical mangrove habitats near Ubatuba, State of São Paulo, Brazil were compared. The size–frequency distribution, sex ratio, and recruitment were evaluated. Sampling was performed monthly from April 2001 to March 2002 in the Itamambuca and Ubatumirim habitats. Crabs were caught manually for 15?min by two collectors during low tide. The carapace width of each crab was measured with a digital caliper, and the sex and ovigerous state were recorded. The median size of the carapace width of males was greater than that of females at both sites (P<0.05). The median size of the crabs from Itamambuca was larger than at Ubatumirim (P<0.05). Only 28 ovigerous females were obtained from both mangroves, which suggested that females might remain in their burrows during the incubation period. The highest recruitment pulse occurred in winter for both populations, probably as a consequence of high reproductive activity during summer. The sex ratio in the size classes showed an anomalous pattern, with a higher frequency of females in the intermediate size classes. This may be related to a greater energy requirement for reproduction in females, thus delaying growth. The variable environmental conditions to which Uca rapax populations are subject appear to act directly or indirectly on the population, causing variations in growth and reproductive processes in the different populations investigated here.     

Aspects of mangal ecology along the Red Sea coast of Saudi Arabia

Surveys of the mangal along the Red Sea coast of Saudi Arabia form the basis of this study. Both soft-bottomed mangals and the less well known hard-bottomed mangals are represented. The distribution of Avicennia marina, the dominant mangrove species, is discontinuous in the northern part of the Red Sea. Its development increases southwards, and mean height is inversely correlated both with latitude (P<0·05) and salinity (P<0·05). Another species, Rhizophora mucronata, was recorded in only five areas. Molluscs and crabs represent the principal faunal elements within the mangal. The density of Cerithidea cingulata, the dominant mollusc species, shows significant correlation (P<0·01) with the abundance of blue-green algae. Four species of fiddler crab (Uca) are included among the crab fauna of the mangal, one of which (U. urvillei) is here newly recorded for the Red Sea. Evidence is given for suggesting that the mangal biota in the region sampled may not be distinctive. Rather, it consists of many species found not only within the mangal but also in other habitats such as seagrass beds and even rock beaches. It is suggested that the mangal of the Red Sea represents a composite habitat, containing both hard and soft substrates and inhabited by species typical of each. This contrasts with the situation in most other mangals studied.