Stalked crinoids from Tasmanian seamounts. Part 1: Hyocrinidae

Faunal investigations conducted in 1997 on southern Tasmania seamounts, produced 10 specimens of stalked crinoids belonging to the family Hyocrinidae. These are the first hyocrinids to be recorded from this area. Three new species are described: Feracrinus koslowi sp. nov., Ptilocrinus tasmaniaensis sp. nov. and Ptilocrinus australis sp. nov. New data show that three previously described species should be referred to a single species Feracrinus aculeatus Mironov and Sorokina, 1998 and the genus Camaecrinus Mironov and Sorokina, 1998 becomes a junior synonym of Feracrinus. Although they have close affinities, the two species belonging to the genus Feracrinus live in different areas of the western Pacific. Ptilocrinus tasmaniaensis sp. nov. and P. australis sp nov. are the shallowest known species in the genus Ptilocrinus (sensu stricto). There is no evidence of endemism in hyocrinids living on south Tasmania seamounts.     

The juvenile stages of Parastacus brasiliensis (von Martens, 1869) (Crustacea,Decapoda, Parastacidae)

The family Parastacidae consists of the freshwater crustaceans popularly known as crayfishes or crawfishes. Only the genus Parastacus occurs in Brazil, with P. brasiliensis (von Martens, 1869) endemic to the state of Rio Grande do Sul in southern Brazil. Parastacids have direct development, ecloding as juveniles. In laboratory‐reared specimens, juvenile I stage is similar in morphology to the adult, with no setae on most appendages, absence of uropods and presence of a hook on the dactyl of pereiopods 4 and 5. The juvenile II retains juvenile I characteristics but has more setae, which are more varied in morphology. The juvenile III possesses setae as the adults, fully formed uropods and the hooks on pereiopods 4 and 5 are substituted by an apical rectilinear dactylus.     

Studies on the provenzanoi and other pagurid groups: VI. Larval and early juvenile stages of Pagurus ochotensis Brandt (Decapoda; Anomura; Paguridae) from a northeastern Pacific population,reared under laboratory conditions

Zoeal, megalopal, and early juvenile stages of Pagurus ochotensis (Brandt, 1851) from a northeastern Pacific population are described from laboratory-reared individuals. Zoeal and megalopal development in this population is compared with that described for a population of this species from Hokkaido, Japan. First and second juvenile crab stages of this species are described for the first time. The nearly identical developmental morphology of the two populations supports the earlier synonymy of the northeastern Pacific species, Pagurus alaskensis (Benedict) with P. ochotensis.     

Comparative morphology of the otolith of the triplefins (family: Tripterygiidae)

Otolith morphology may provide useful information about the triplefin fish family Tripterygiidae. A comparative study of the otolith of 40 tripterygiid species was conducted to identify the most appropriate taxonomical characters that can separate the species and genera of the family Tripterygiidae. Among other otolith characters, it is possible to distinguish characters that clearly define a taxonomic group (genus or species), and other characters that are shared by several genera, but may be only useful to define certain species within a genus. Ontogenetic changes in the otolith of the triplefin fishes studied are evident. The otolith of the juvenile Ucla xenogrammus was the most similar to the adult otolith, while otolith of the juvenile Blennodon dorsale was the least similar to the adult otolith.     

An ontogenetically stable sexual character in a montane agamid,Salea horsfieldii Gray, 1845 (Reptilia: Agamidae) from Nilgiris,India

Many agamid lizards are known to show sexual dimorphism in body shape, colour and ornamentation or a combination of these traits. Adult males of Salea horsfieldii have a discontinuous dorsal crest at the nuchal region, which is a sexually dimorphic character. However, there is no information about the age or size at which this dimorphic ornamentation develops and if the species exhibits sexual shape dimorphism (SShD). The authors studied the morphology of S. horsfieldii and found that its ornamentation is an ontogenetically stable character present in all males, including juveniles. Seven morphological characters were measured to determine if they exhibited SShD at adult and juvenile stages. Analysis of covariance was used to identify differences in morphology between sexes. The results show that only adults exhibited SShD, but not juveniles. Adult males had larger head and foot lengths in comparison to females of the same size. Larger head length in adult males is a sexual fitness trait, which increases bite-force during intra-sexual combats. Although the presence of sexually dimorphic ornamentation right from the juvenile stage is rare in agamids, S. horsfieldii is an exception . The role of sexually dimorphic ornamentation at juvenile stages remains unknown and requires further investigation.     

Hypersymbioses in the pinnotherid crabs (Decapoda: Brachyura: Pinnotheridae): a review

Members of the brachyuran family Pinnotheridae are nearly all symbionts of other invertebrates; some crabs are parasitic and others are commensal. Most live inside bivalve molluscs or in the tubes or burrows of polychaetes and other marine organisms. Animals living on or in pinnotherid crabs are considered to be hypersymbiotic and are reviewed here. Hypersymbionts are poorly represented within only 26 members (～8.6%) of the Pinnotheridae (20 species in the subfamily Pinnotherinae and six species in the Pinnothereliinae). Parasitic hypersymbionts are as follows: three species of fungi; one cestode larva (undescribed procercoid of Trypanorhynchida); one trematode metacercaria (undescribed Microphallidae); nematode cysts (undescribed); three species of Nemertea (Carcinonemertidae, two undescribed); two species of rhizocephalan Cirripedia (Sacculinidae; plus five or more undescribed potential sacculinid species); epicaridean Isopoda [13 species of Bopyridae (one undescribed) and four species of entoniscids (Entoniscidae, three undescribed)]. Preliminary biological information on undescribed entoniscids is presented. Several mainly incidental hypersymbioses involving ectosymbionts are known primarily from Pinnixa chaetopterana, a symbiont of polychaete burrows. The ctenostome bryozoan Triticella elongata is the only known obligate ectosymbiont in P. chaetopterana, but it also infests five other species of pinnotherids. Some of the other ectosymbionts (all incidental) on P. chaetopterana are stalked ciliates, hydroids, juvenile polychaetes, bivalve molluscs, balanomorph barnacles, harpacticoid copepods and urochordates. Species of ectosymbionts including an ectoproct bryozoan have been reported from other pinnotherid species. Factors influencing our meagre knowledge of hypersymbioses in the Pinnotheridae are discussed, among them the inaccessibility of crab hosts and research emphasis on taxonomy within the family.     

Carapace ontogeny of the bromeliad dwelling ostracod Elpidium bromeliarum Müller, 1880 (Crustacea: Ostracoda)

Ostracods have discontinuous development, marked by ecdyses, and determinate growth. Ontogenetic studies have suggested a pattern of nine postembryonic stages (eight juvenile phases and the adult) for the main freshwater ostracod superfamilies Cypridoidea, Cytheroidea and Darwinuloidea. However, cases of a supposed extra moult in the adult stage have been proposed for some ostracod species, which would amount to 10 postembryonic growth stages. One such example is Elpidium bromeliarum Müller, 1880, a cytheroidean that inhabits tank-bromeliads. The present study is aimed at investigating the ontogenetic development of E. bromeliarum using width and length measurements, as well as carapace and appendage morphology in order to test the existing hypothesis of an additional growth stage in adults of this species. Our results revealed nine postembryonic growth stages (eight juvenile and the adult), with sexual dimorphism beginning its expression in the last juvenile stage. Thus, the ontogenetic development of E. bromeliarum agrees with the overall pattern observed for podocopid ostracods and the hypothesis of 10 postembryonic growth stages was not corroborated. We argue that the inability to differentiate juveniles from adults, or different species from one another, may have misled to the assumption of an additional moult in E. bromeliarum.     

External morphology of Coptophylla caroliniani and Aceria mississippiensis spermatophores (Prostigmata: Eriophyidae)

The spermatophores of Coptophylla caroliniani and Aceria mississippiensis consist of a base which is glued to the substrate by an adhesive substance, a stalk, and an expanded head with a sperm packet resting on a central projection. The C. caroliniani spermatophore has a twisted stalk whereas the A. mississippiensis spermatophore has a straight stalk that is twisted near the junction of the head and stalk. A fan-shaped head is characteristic of a C. caroliniani spermatophore whereas A. mississippiensis has a shield-shaped head. The central projection which attaches the sperm packet to the head is oblong in C. caroliniani and cylindrical in A. mississippiensis.     

Another migid in the wall: natural history of the endemic and rare spider Calathotarsus simoni (Mygalomorphae: Migidae) from a hill slope in central Argentina

A population of Calathotarsus simoni Schiapelli and Gerschman (1975) was discovered on a hillside in the Ventania system, Argentina. Our objectives were to quantify burrow density, record burrow morphology and door characteristics and describe the micro-habitat. We counted 57 burrows and report a density of 0.01 burrows/m². Aggregation indices suggest that burrows are aggregated under some area plots but more evenly distributed on others. The trapdoor is thick and rigid with bevelled edges connected to the entrance rim by a narrow articulated hinge. Two egg sacs from females were obtained and data on eggs and spiderlings are presented. We registered six burrows of an undetermined species of Actinopus. While a few specimens of Actinopus sp. were found inhabiting this hillside, the highest proportion of burrows belonged to C. simoni. Spider diversity on the hillside shows the predominance of Linyphiidae, Nemesiidae and Gnaphosidae. One juvenile of C. simoni was captured using pitfall traps.     

A revision of Monocotyle Taschenberg, 1878 (Monogenea: Monocotylidae) with descriptions of three new species from Australia

Monocotyle is revised and three new species are proposed. Monocotyle corali sp. nov. is described from the gills of the cowtail ray, Pastinachus sephen (Forsskål) (Dasyatididae), and is distinguished from other members of Monocotyle by the large hamuli with a distinct tail on the guard and by the male copulatory organ with three loops and a wing-like accessory piece at the distal end. Monocotyle jordani sp. nov. from the gills of the southern eagle ray, Myliobatis australis Macleay (Myliobatididae), is differentiated by the male copulatory organ with a large, unique accessory piece. Monocotyle youngi sp. nov., from the gills of Himantura fai Jordan and Seale (Dasyatididae), has marginal haptoral papillae armed with 12 to 15 sclerites, a male copulatory organ with 20 loops and a unique accessory piece at the distal end. Monocotyle trygoni (Venkatanarsaiah and Kulkarni, 1980) Timofeeva, 1985 is synonymized with M. spirophallus Tripathi, 1959 and M. spirophallus is redescribed fully. There are now 16 valid species of Monocotyle and a key to species is presented. Additional data and illustrations of important taxonomic characters are provided. The developmental sequence of the male copulatory organ of M. spiremae Measures, Beverley-Burton and Williams, 1990 from juvenile to adult is described. The anterior glands and the type of secretion they contain are also documented for several species of Monocotyle.     

Marine protozoan epibionts on the copepod Lepeophtheirus salmonis,parasite of the Atlantic salmon

Two species of ciliate suctorian protozoa belonging to the genus Ephelota, E. gemmipara and E. gigantea, were found as epibionts on the marine copepod Lepeophtheirus salmonis (salmon louse), an ectoparasite of marine salmonid fish, including the Atlantic salmon, Salmo salar. Epibionts were distributed over the cephalothoracic shield, genital segment, abdomen and caudal branches of the copepods. Individuals from both species possessed two types of tentacles: long, prehensile, pointed tentacles and short, adhesive, capitate feeding tentacles. Both species contained a highly ramified and lobated macronucleus. E. gemmipara showed a rounded cellular body attached to a stalk possessing longitudinal and transversal striations but lacking a suprastylar extension. E. gigantea had an umbrella‐shaped cellular body significantly larger than in E. gemmipara, the stalk showing only longitudinal striations but possessing a conspicuous suprastylar extension. This is the first time that the presence of ciliate epibionts has been recorded at species level on the copepod Lepeophtheirus salmonis. Statistical data about the distribution of both species on the surface of the copepod are detailed and a new geographical distribution for E. gigantea is proposed.     

Ascidiacea (Tunicata) from deep waters of the continental shelf of Western Australia

Seventy‐eight species of Ascidiacea, including 21 new species from deeper waters (about 100 m and occasionally to about 500 m) off Western Australia appear to represent a diverse fauna not previously sampled. The relatively few solitary species taken include two possibly introduced (Styela plicata and S. clava). Large aplousobranch colonies dominate the collections. Aplousobranch species with numerous, small, deeply embedded zooids in massive three‐dimensional, vertical and often branched or stalked inflexible colonies supported by embedded sand (Polyclinindae) or calcareous spicules (Didemnidae) are common. Species with flexible stalks (enabling them to respond to prevailing currents) such as Clavelina meridionalis, Sigillina australis and S. cyanea were not taken often. Some known species (e.g. Synoicum chrysanthemum, and Atriolum tubiporum) previously considered rare were taken at these depths in significant numbers. Other unusual taxa (Pseudodiazona longigona and Condominium spp.) are recorded from new locations but do not appear to be common.     

Juvenile Sphaeroma quadridentatum invading female-offspring groups of Sphaeroma terebrans

Female isopods Sphaeroma terebrans Bate 1866 are known to host their offspring in family burrows in aerial roots of the red mangrove Rhizophora mangle. During a study on the reproductive biology of S. terebrans in the Indian River Lagoon, Florida, USA, juvenile S. quadridentatum were found in family burrows of S. terebrans. Between September 1997 and August 1998, each month at least one female S. terebrans was found with juvenile S. quadridentatum in its burrow. The percentage of S. terebrans family burrows that contained juvenile S. quadridentatum was high during fall 1997, decreased during the winter, and reached high values again in late spring/early summer 1998, corresponding with the percentage of parental female S. terebrans (i.e. hosting their own juveniles). Most juvenile S. quadridentatum were found with parental female S. terebrans, but a few were also found with reproductive females that were not hosting their own offspring. Non-reproductive S. terebrans (single males, subadults, non-reproductive females) were never found with S. quadridentatum in their burrows. The numbers of S. quadridentatum found in burrows of S. terebrans ranged between one and eight individuals per burrow. No significant correlation between the number of juvenile S. quadridentatum and the numbers of juvenile S. terebrans in a family burrow existed. However, burrows with high numbers of juvenile S. quadridentatum often contained relatively few juvenile S. terebrans. The majority of juvenile S. quadridentatum found in family burrows of S. terebrans were smaller than the juvenile S. terebrans that were cared for by their mothers. The results indicate that the presence of S. quadridentatum in S. terebrans family burrows may negatively affect the duration of extended parental care in S. terebrans. It is not known why parental female S. terebrans are not able to discriminate against juvenile S. quadridentatum. Possibly, the fact that the two species are closely related facilitates S. quadridentatum sneaking into S. terebrans family burrows.     

Hairworms found in Scottish agricultural land,with descriptions of two new species of Gordionus Muller (Nematomorpha: Gordiidae)

Three species of Nematomorpha were found in a survey of the ground beetles of Scottish agricultural land, Gordionus violaceus (Baird) and two undescribed new species, G. linourgos sp. nov. and G. diligens sp. nov. The morphology of all three species is studied with the aid of SEM, and the characteristics of the cuticle and the male terminal lobes described in detail. All species were found to be parasitic in ground beetles of the family Carabidae, in nine different species (Nebria brevicollis (Fabricius), Harpalus latus (Linnaeus), four species of Pterostichus, and three species of Calathus). Gordionus violaceus is also reported to be a parasite of the spider Arctosa alpigena (Lycosidae). Up to four specimens were found in the same host, typically one adult and several juvenile forms. Parasitized hosts had severe alterations of their reproductive, digestive and secretory systems. The three species of Gordionus were mostly found in grasslands and coniferous forest, most abundantly in June and July.     

Observations on variation in body coloration and patterning in Limax flavus L and Limax pseudoflavus Evans

Summary

L. flavus and L. pseudoflavus can be distinguished and separated by the differences in the patterning of the external body coloration. The light coloration was expressed as small speckles in L. flavus causing the animals to have a dusky appearance and in L. pseudoflavus of blotches causing a mottled appearance. The two species overlapped in the range of coloration although L. pseudoflavus from Ireland tended to be darker and greener than L. flavus. In L. flavus the juvenile keel stripe persisted longer than in L. pseudoflavus and could persist, in some animals, until they were a third to a half, grown. Coloration could be affected by keeping animals in the laboratory: L. pseudoflavus originating from material collected from Ireland became much darker than the original material, with a wider range of mottling. Despite the two species having much greater similarity in external appearance than originally reported, there was no overlap in the diagnostic characters of the distal genitalia.