Description of two new species and a new genus of bopyrid isopod parasites (Bopyridae: Pseudioninae) of hermit crabs from China

This is the first record from China of the bopyrid isopod genus Asymmetrione, of which the new species Asymmetrione globifera, a parasite of the hermit crab Dardanus hessii (Miers) in Beibu Gulf and South China Sea, is described. The female A. globifera differs from Asymmetrione nossibensis Bourdon in the shape of its barbula and ornamentation of the first oostegite. A tabulation of the occurrence of all currently known species of Asymmetrione is included. New genus Parasymmetrione is described. The type species, Parasymmetrione tuberculineata, sp. nov., a parasite of Clibanarius corallinus (H. Milne-Edwards) Xisha, is similar in appearance to Asymmetrione spp. but differs, in the female, in not having the propodi of its pereopods produced into sockets and having uniramous uropoda; the male of P. tuberculineata sp. nov. differs from species of Asymmetrione in having the dactyli of only its first pair of pereopods markedly longer than those of the following pereopods.     

Description of a new species of Asymmetrione (Isopoda: Bopyridae: Pseudioninae) infesting the hermit crab Paguristes tomentosus (Anomura: Diogenidae) from Peru,with a key to species and a review of southeastern Pacific bopyrids

A new species of bopyrid isopod is described from a host hermit crab Paguristes tomentosus collected from Pisco, Peru and assigned to the pseudionine isopod genus Asymmetrione Codreanu, Codreanu and Pike, 1965. This is the second species in the genus with less than 20° asymmetry in females, but agrees with all other species in the genus in having the characteristic “socket” on the propodus of the female's pereopods, and in all characters of the males. A key is provided to the 10 species now in Asymmetrione. New records of an Anathelges sp. from Pagurus villosus collected in central Chile are given but additional material is required to determine whether these specimens represent the eastern Pacific A. thompsoni or the western Atlantic A. hyptius. A review of all the bopyrid species known from the western South American coast, with remarks on their taxonomy and biology, is provided.     

X.—New Hymenoptera of the family Bethylidæ

What seems likely to be the first published record of a foraminiferan protozoan (Cibicides lobatulus) epizoic on an isopod (Astacilla longicornis) is reported from material collected by divers off the Berwickshire coast (Scotland). Notes are also provided on other epibionts and a comparison is made with Astacilla from the Clyde Sea area which proved to have a much lower incidence of fouling. There, fouling was due largely to the entroproct Barentsia sp. and the hydroid Clytia hemisphaerica, not to Cibicides.     

Epibiontic communities on the freshwater shrimp Caridina ensifera (Crustacea,Decapoda, Atyidae) from Lake Poso (Sulawesi,Indonesia)

The epibiont communities of the freshwater shrimp Caridina ensifera, endemic to Lake Poso (Sulawesi, Indonesia), were analysed for the first time based on their morphological and biometrical characteristics and taxonomic position. Seven ciliated protozoans and a rotifer were examined: three suctorian ciliate protozoan species (Acineta sulawesiensis, Podophrya maupasi, and Spelaeophrya polypoides), three peritrichs (Zoothamnium intermedium, Vorticella globosa, and Cothurnia compressa), a haptorid (Amphileptus fusidens), and the rotifer species Embata laticeps. A mean number of 314.6 epibionts was found per shrimp specimen. The distribution of the epibiont species on the surface of the basibiont was recorded, to allow calculation of the density on the different colonized individuals of C. ensifera and on each anatomical unit of the shrimp. The most abundant species, Zoothamnium intermedium and Acineta sulawesiensis, were also the ones most widely distributed. The statistical analysis showed that Zoothamnium, Acineta, Podophrya, and Embata were the epibiont genera most widely distributed on the basibiont, and the pairs of epibiont genera Zoothamnium–Embata, Podophrya–Acineta, Spelaeophrya–Amphileptus, and Cothurnia–Vorticella followed a similar pattern of distribution. There was a significant difference between the distribution patterns of the different epibiont species on the shrimp. The analysis of the densities of the epibionts throughout the longitudinal axis of the shrimp showed a gradient from the anterior to the posterior end of the body, and a significantly different distribution of each epibiont species. Their colonization follows a certain pattern of behaviour, the species occupying the available substratum, with particular requirements of each functional group, but with a trend resulting in equilibrium among species and groups, compensating for diversity and density. The possible adaptations of the epibionts, as well as the colonization patterns are discussed.     

The larval development of Argulus coregoni Thorell (Crustacea: Branchiura)

Summary

The larval development of Argulus coregoni from the first to the ninth stage was studied, with special reference to the morphological changes of the appendages and some other parts of the body.

A newly hatched larva is a copepodid-form measuring 0·6–0·7 mm long and approaches the shape of the adult after moulting into the second stage (0·7–0·9 mm). Throughout the larval stages, the first maxilla shows the most remarkable modification. The larvae of the first to the fifth stage are equipped with two strong, curved claws, which act as a clasping organ, at the terminal segment of the first maxilla. The basal segment expands considerably at the third stage (0·9–1·1 mm) prior to forming a sucker at the sixth stage (1·7–2·2 mm). The claws start to degenerate at the fifth stage (1·4–1·8 mm), but are still recognizable as a rudiment after the seventh stage (2·2–2·6 mm). The other distinct morphological changes that occurred are: (1) bifurcation of the anterior part of the dorsal ridges on the carapace, (2) development of the male accessory copulatory organ at the basal segments of the second to the fourth legs, (3) number of posteriorly directed minute spines on the ventral surface of the carapace, (4) number of elements in the supporting ribs of the suckers, (5) number of spines found at the first segment of the second maxilla, and (6) number of setae on the four pairs of thoracic legs.

The larval forms of A. coregoni younger than the fourth stage (1·1–1·4 mm) are indistinguishable from those of A. japonicus and A. foliaceus.     

New genera and species of the Synchelidium group (Amphipoda: Oedicerotidae) from Asia-North Pacific

Four new species and two new genera belonging to the family Oedicerotidae are reported from Korea and Vietnam. Two new genera, Orthomanus and Imbachoculodes are described, with three new species, namely Orthomanus koreanus gen. et sp. nov., Imbachoculodes namhaensis gen. et sp. nov. and Imbachoculodes vietnamensis gen. et sp. nov. The monotypic genus Orthomanus is characterized by the very short carpi and transverse palms of gnathopods 1 and 2, the reduced dactyli on pereopods 3–6, and the greatly enlarged distolateral spine-tooth on the outer plate of maxilla 1. Imbachoculodes has slender gnathopods 1 and 2 with elongated carpi, pereopods 3 and 4 with elongated dactyli, and a narrow basis of pereopod 7. The fourth new species, Sinoediceros hwanghaensis sp. nov. has a greatly reduced flagellum on antenna 2, a broadened meri on pereopods 3 and 4, and an elongated maxilliped outer plate. Keys are provided to 1) the North Pacific genera of the Synchelidium group, 2) species of Imbachoculodes, and 3) species of Sinoediceros.     

New genera of Bogidiellidae (Amphipoda: Gammaridea) from SW Pacific and Mediterranean marine caves

Two new genera and species of the stygobiont gammaridean amphipod family Bogidiellidae are described from anchialine or fully marine subterranean habitats in Mediterranean and SW Pacific Islands. Fidelidiella pectinata, from a littoral cave in Lifou (Loyalty Islands), differs from any other bogidiellid known thus far by the presence on the left mandible of a modified lacinia which is hypertrophied and expanded laterally, and by the possession of a transverse row of strong rounded processes on the anterior side of the distomedial corner of the fourth segment of the maxillipedal palp. This is the most easterly record of bogidiellid amphipods in the SW Pacific. Racovella uniramea, discovered in a Mallorcan anchialine cave, is remarkable among the Bogidiellidae in exhibiting a combination of only six distal spines on the basal endite of the maxillule, and presence of coxal gills on pereopods 3–6. We place particular emphasis on the determination of segmental homologies of all limbs and on the resolution of fine‐scale integumentary details, in order to provide a sound basis for future comparison with other family members.     

First record of the genus Atlantistylis Reyss, 1975 (Crustacea: Cumacea) from the North Atlantic,with the description of a new species

A new species of the genus Atlantistylis Reyss, (Diastylidae) is described from the Atlantic Frontier Margin (North‐East Atlantic). This is the first record of the genus Atlantistylis from the North Atlantic. The new species Atlantistylis borealis can be recognized by the presence of spines on the frontal and lateral lobes of the carapace combined with their absence on the pereon and pleon; the first pereopods are very long. The small telson with two small apical acuminate setae and the absence of pleopods in the male are characteristic of the genus.     

Reproductive biology of Limnoria chilensis: another boring peracarid species with extended parental care

Several boring peracarid species engage in extended parental care with parents tolerating small juveniles in their burrows, but only anecdotal observations have been reported from boring isopods of the genus Limnoria. The isopod Limnoria chilensis Menzies is frequently found in holdfasts of the macroalgae Macrocystis pyrifera (L.) C. Agardh and Durvillea antarctica (Chamisso) Hariot. In the present study, holdfasts of D. antarctica that harboured L. chilensis were carefully dissected in order to examine the association pattern of reproductive females and small juveniles. In most infested holdfasts, L. chilensis reached very high densities of 43.7 ± 3.9 (mean ± SE) individuals cm^?2 (range: 0–90 individuals cm^?2). The overall sex ratio (females:males) was close to unity (1.2). Male size varied between 1.5 and 2.6 mm body length (BL) and female size between 1.5 and 3.6mm BL. The percentage of reproductive females was low (19.7% of all females), and only the largest females (>2.6 mm BL) were reproductive. Embryo numbers ranged between six and 19 per female and a significant correlation between female BL and the number of embryos was found. Several females were found with small juveniles (0.8–1.2 mm BL) in the terminal end of their burrows. On several occasions, aggregations of similar-sized juveniles (1.0–1.5 mm BL) in their own burrows were found near a female burrow, indicating that these juveniles initiated their first individual burrows from within the maternal burrows. Some females with small juveniles in the terminal end of their burrows were either accompanied by males or they were ovigerous, indicating that they may have been in the process of producing a second brood. The fact that juveniles build their first burrows in the protection of female burrows suggests that such small juveniles have not yet developed full boring capacity. Extended parental care in this (and other boring) peracarid species represents a mechanism facilitating high juvenile survival rates. Given the highly local recruitment, it is suggested that the reproductive biology of this isopod has strong implications for Its population biology.     

Meteorus acerbiavorus sp. nov. (Hymenoptera,Braconidae), a gregarious parasitoid of Acerbia alpina (Quensel) (Lepidoptera,Arctiidae) in North Finland

The new gregarious parasitoid Meteorus acerbiavorus sp. nov. (Hymenoptera, Braconidae) was reared from the cocoons of Acerbia alpina (Quensel) (Lepidoptera, Arctiidae) in north-western Finnish Lapland. This species belongs to Meteorus rubens (Nees) species group and differs from the most related M. rubens in the following features: the eyes densely setose; the median lobe of the mesoscutum, scutellum, mesopleuron, and the hind coxa entirely or at least partly rugulose-granulate or rugose-areolate and sometimes with granulation; the ovipositor subapically with distinct dorsal node; the ventral borders of the first metasomal tergum weakly separated by narrow space in its basal half; the colour of the body and legs mostly or entirely dark; the fore wing more or less darkened. Phylogenetic relationships among several Meteorus species close to M. rubens including new M. acerbiavorus were investigated based on DNA sequence fragments of the mitochondrial COI and the nuclear 28S rDNA genes. The discussions on the species groups of Meteorus, on distribution of Acerbia alpina in the Holarctic and on its known parasitoids are presented.     

Desmosomatidae and Nannoniscidae (Crustacea,Isopoda, Asellota) from bathyal and abyssal depths off North Carolina and their evolution

The deep-sea asellote isopod (Crustacea) species, belonging to the families Desmosomatidae and Nannoniscidae, were studied from R/V Eastward collections of Duke University from three study sites off North Carolina. The Desmosomatid isopod Eugerda svavarssonni n. sp. is described from Site Alpha at 620m. Eugerda latipes Hansen, previously known from boreal North Atlantic, is also reported from this upper slope site. Two new desmosomatid isopods, Mirabilicoxa hessleri n. sp. and M. alberti n. sp., and a new nannoniscid isopod Exiliniscus chandravoli n. sp. are also described from site Beta from 2700 to 3700 m. A nannoniscid isopod Leutziniscus jebamoni gen n., n. sp., and a desmosomatid isopod, Prochelator sarsi n. sp., are described from the deepest study site Omega in the Hatteras Abyssal Plain. A new genus, Nannoniscella is erected to accommodate Nannoniscoides bicustatus Siebenaller and Hessler, 1977. This paper also includes discussions on comparative morphology and sexual dimorphism in species of Mirabilicoxa, zoogeography of species of the genus Eugerda and phylogeny with emphasis on the genus Prochelator.     

Some new parasitic copepods (Siphonostomatoida: Nicothoidae) from deep-sea asellote isopods

Summary

The highly transformed siphonostomatoid Choniorhiza enaulis gen. et sp. nov. is described from an asellote isopod, Dendromunna sp., in the deep North Atlantic Ocean to the south west of the Azores. Male and female live inside a cyst on the dorsal side of the branchial chamber of the isopod. The new genus may be distinguished from all other genera of the Nicothoidae, except Rhizorhina, by the presence of oral processes replacing the cephalic appendages. It differs from Rhizorhina in the presence of a distinct urosome in the female. A key to all genera of the Nicothoidae is provided and Pseudonicothoe Avdeev & Avdeev is recognized as a junior synonym of Paranicothoe Carton. The male syntype of Paranicothoe cladocera Carton is designated as the lectotype because the female is an isopod. Sphaeronella bradfordae sp. nov. is described from an isopod of the genus Haploniscus caught on the Chatham Rise off New Zealand.     

Crustaceans associated with the deep-water gorgonian corals Paragorgia arborea (L., 1758) and Primnoa resedaeformis (Gunn., 1763)

To explore the crustacean fauna associated with deep-water gorgonian corals, suction samples were taken from colonies of Paragorgia arborea and Primnoa resedaeformis using a Remotely Operated Vehicle. Seven colonies of P. arborea and eight of P. resedaeformis were sampled from 330–500?m depth in the Northeast Channel off Nova Scotia. A total of 17 species were identified as being associated with the corals. The P. arborea fauna was richer than the P. resedaeformis fauna in both abundance and number of species, with 1303 versus 102 individuals and 16 versus seven species, respectively. However, 13 of the species associated with P. arborea were from hydroids attached to the coral. Amphipods dominated the fauna both in abundance and numbers of species and the most common species were Metopa bruzelii, Stenopleustes malmgreni, Proboloides calcarata and Aeginella spinosa. The isopod Munna boecki and the cirripede Ornatoscalpellum stroemii were also quite common. The most strongly associated crustaceans were two parasitic poecilostomatid copepods; these are common also on tropical gorgonians and are most likely obligate associates. The frequently occurring shrimp Pandalus propinquus probably avoids predation by seeking protection among the coral branches. Shrimp counts from video records showed that visual inspection without physically disturbing colonies will generally not reveal the crustaceans hidden in coral colonies. The galatheid Eumunida picta was observed on P. resedaeformis colonies. The fauna of the deep-water gorgonians corresponded to the fauna of tropical shallow-water gorgonians in the numerical dominance of amphipods and parasitic copepods; however, species richness is higher and decapods, which constitute a rich fauna on tropical gorgonians, were only represented by two species.     

Biology and life cycle of Tmetonyx similis (G. O. Sars, 1891) (Amphipoda,Lysianassidae), a scavenging amphipod from the continental slope of the Mediterranean

The present study focused on the biology and life cycle of Tmetonyx similis, a scavenging amphipod inhabiting the continental slope of the north‐western Mediterranean. All the categories of individuals were observed in the samples. The emergence of offspring occurs in successive cohorts. The lifespan of the females is longer than that of the males, but the sex ratio is strongly in favour of the males. The fecundity was found to be lower than that of the other female crustaceans present in these samples. The growth pattern was modelled. A strong correlation was observed between the length and the weight of the animals collected. Several hypotheses are proposed to explain a sex ratio in favour of males. This result may be explained by a migratory process of the females of T. similis. A comparison of the reproduction strategy is given for the three main scavenger crustacean species (amphipods and isopod) collected in this area.     

Two new Falcaustra Lane, 1915 species (Nematoda: Kathlaniidae) from African pipids (Anura)

Two new species of Falcaustra Lane, 1915 are the first to be reported in amphibians from mainland sub-Saharan Africa. Falcaustra puylaerti n. sp. occurs in hosts of the Xenopus (Silurana) tropicalis group in Sierra Leone, Togo and Nigeria. Falcaustra hinkeli n. sp. infects Xenopus (Xenopus) fraseri group hosts at localities in the Cameroon and the Democratic Republic of the Congo. Falcaustra hinkeli and F. puylaerti are probably sister species with respect to described congeners and can be differentiated from each other by the form of the cheilostomal structures, the morphometrics of the anterior body, and by a large difference in male spicule length. Both lack a precloacal pseudosucker and are separated from other Falcaustra spp. which share this characteristic by the pattern of male caudal papillae and by a cheilostomal ring with associated sclerotized elements and posteriorly directed projections. Evolutionary aspects of the host-parasite relationship are discussed. Although alternative hypotheses are possible, the distinctive cheilostomal morphology, the sister species relationship and the host specificity pattern of F. hinkeli and F. puylaerti are consistent with their having undergone an extended evolutionary association with the host genus.     

Trophobiosis between ants and Eurystethus microlobatus Ruckes 1966 (Hemiptera: Heteroptera: Pentatomidae) a cryptic,gregarious and subsocial stinkbug

In this study we describe trophobiosis between ants and Eurystethus microlobatus (Hemiptera: Pentatomidae) at a highland quartzite rocky outcrop in southern Espinhaço Range, southeastern Brazil. We found stinkbugs exclusively on the mistletoe Psittacanthus robustus (Loranthaceae). The stinkbug species is gregarious, forming dense clusters, with females guarding eggs and young nymphs. In addition, this species presents cryptic colouration and most individuals were located on roots and shoots, camouflaged within the bark. Eurystethus microlobatus produced honeydew by day and night, and four ant species attended aggregations: Camponotus rufipes, Camponotus crassus, Camponotus melanoticus and Cephalotes pusillus. Camponotus rufipes was the most frequent and aggressive, and the only species to attend the stinkbugs by day and night. This is the first documented case of trophobiosis between true bugs and ants in the New World.     

Biology of a tropical intertidal population of Cerithium atratum (Born, 1778) (Mollusca,Gastropoda)

The spatial distribution, population structure and secondary production of the gastropod Cerithium atratum were studied in the intertidal region of Engenho d'Água Beach in São Sebastião Channel on the northern coast of the state of São Paulo, Brazil, from May 1998 to April 1999. Twenty monthly samples were taken using a 0.25×0.25?m quadrat in each of two areas. Individuals showed a clustered dispersion pattern in both areas throughout the sampling period. Abundance and mean shell size were related to period of the year and to intertidal level, although no consistent pattern could be described when comparing the two sampling areas due to significant interaction between time and locality. Migratory events were evidenced by marked year-round variations in the frequency of individuals in the largest size classes. Thus, the size structure of this population could not be explained by recruitment and growth alone. Almost 90% of the intertidal population was represented by small individuals that recruited at the beginning of the sampling period (May to August 1998). The intertidal population was composed of annual cohorts formed by individuals recruited in different years. Each annual cohort could be divided into sub-cohorts with closely spaced recruitment periods in the same breeding season. The growth and annual P/B ¯ ratio (where P is the annual somatic production and B ¯ is the mean annual biomass) was estimated for the first year of life of recruits from 1998 occupying the intertidal region. Individuals may have an increment of up to 15?mm in shell length during the first year of life, but the growth was more pronounced in summer months. The high value of P/B ¯ (3.902) was a consequence of the dominance of small-sized individuals, which have a higher weight-specific increment than large-sized ones.     

Is the Caprellidea a monophyletic group?

Cladistic analysis of caprellidean genera has revealed major divergence near the outgroup producing two major lines of evolution: Pseudoprotomima-Perotripus, and Caprogammarus-Caprella. The most plesiomorphic genus of each line, Pseudoprotomima and Caprogammarus, respectively, shows different plesiomorphic characters to each other. Pseudoprotomima has pereopods III and IV with 6 articles, antenna II flagellum with > 2 articles and three pairs of gills, while Caprogammarus has an abdomen 5-segmented with three pairs of pleopods. Pseudoprotomima and related genera are distributed from the temperate regions of the northern hemisphere to the South Indian Ocean, while Caprogammarus and related genera are recorded primarily from the boreal region of the northern hemisphere. That pereopods III and IV in Pseudoprotomima and its relatives have 6 articles indicates the functional gap from the Podoceridae (Gammaridea)-Caprogammaridae-Caprellidae gradation, since in the Podoceridae to the Caprellidae these pereopods are not used for clinging to substrata and, even in the Podoceridae, are reduced in size. This shows the possibility that the Caprellidea is not a monophyletic group. A new phylogeny derived from the present study is proposed for future study.     

Four new species of the Diphascon nobilei group (Eutardigrada,Hypsibiidae)

The existence of a group of species similar to Diphascon (Diphascon) nobilei is shown. These species have some common characteristics: a well‐evident drop‐shaped thickening between the buccal tube and the pharyngeal tube, pharyngeal bulb, more or less elongate, with three rod‐shaped macroplacoids and microplacoid, claws of the hind legs different from those of the first three pairs of legs in having a very wide basal portion and indented basal margin, basal spurs also present on the external claws and, in some cases, also on the internal claws of the first three pairs of legs. Four new species of this group are described: Diphascon (D.) serratum, D. (D.) nelsonae, D. (D.) platyungue, and D. (D.) hydrophilum. They differ from one another in the dimensions and shape of the claws; in some cases the difference also affects the value of the ptd index relative to the insertion point of the stylet supports, the buccal and the pharyngeal tube length or the macroplacoid length.