Two new species of heavily calcified cyclostome bryozoans from the intertidal of Akkeshi Bay,Hokkaido, Japan

Cyclostome bryozoans are relatively uncommon in intertidal habitats, where they are subordinate to cheilostomes and ctenostomes. Those that do occur tend to have small colonies that are relatively weakly calcified. Here we describe two new species of intertidal cyclostomes from Akkeshi Bay in northern Japan that are unusual in having large, heavily calcified colonies. One of these – Favosipora ainui sp. nov. – is the first species of this genus recorded from Japan. The second species – Disporella ezoensis sp. nov. – although belonging to a genus well known from Japan and elsewhere globally, is unusual for Disporella in possessing colonies that are vivid red in colour.

http://zoobank.org/urn:lsid:zoobank.org:pub:995903E6-9C07-436A-B788-29BDE2FD5A88     

Along‐ and across‐shore components of the spatial distribution of the clam Tivela mactroides (Born, 1778) (Bivalvia,Veneridae)

Beach clam fisheries often provide an alternate income for traditional fishermen, but this activity is highly vulnerable to urbanization of coastal areas. Tivela mactroides is a beach clam commonly harvested in the Caribbean (Venezuela) and on the south‐eastern Brazilian coast. Only localized records on its spatial structure in size and abundance are available to support management of this clam. The present study showed that the spatial distribution in abundance and size of T. mactroides in Caraguatatuba Bay, state of São Paulo, Brazil, has both along‐ and across‐shore (intertidal and subtidal) components. The nature of this distribution should be taken into account in the design of further population or monitoring studies concerning this species. Clam density varied along‐shore, with a tendency towards higher numbers of individuals in the stations near the northern side of river mouths of this bay. Lower densities were related to the occurrence of sea‐stars and sand‐dollars. The intertidal and subtidal across‐shore distribution of clam abundance and size varied between and within areas (southern and northern). The individuals from the southern area were concentrated at intermediate tidal levels (0.2–0.6 m in relation to mean low water), whereas in the northern area the clams were more homogeneously distributed. The uppermost limit of their distribution was 0.8 m (southern) and 0.4 m (northern), and an upwards tendency towards increased size was more evident in the northern area. In the subtidal, abundance and individual size tended to increase from the deepest (4.5 m) to the shallowest (0.5 m) levels only in the southern area. Individual clams in the northern area tended to be smaller and more abundant than in the southern area. The species had an ontogenic distribution: small‐sized individuals were recorded only in the subtidal. Possible causes for these patterns and for the differences between areas (human exploitation, organic pollution, beach morphodynamics, differential recruitment, and adult–larvae interactions) are discussed, and specific studies are suggested to evaluate formally the proposed hypotheses.     

The distribution and habitat preferences of the Afro-European species of Dynamene (Crustacea: Isopoda)

Summary

The geographical distribution of the genus Dynamene is described in the light of the recent discovery of three new species. D. bidentata appears to have a Boreal distribution whilst that of D. edwardsi and D. magnitorata is Atlanto-Mediterranean. D. torelliae, D. bifida, and D. tubicauda have a Mediterranean distribution but the first species may extend into the Black Sea. Only one species, D. ramuscula, has been recorded outside the Afro-European region, in S.E. Australia. The ranges and habitat preferences of those species outside the Mediterranean overlap as do some of those within the Mediterranean, particularly in the Naples Bay region. Juveniles of D. bidentata inhabit and feed on intertidal algae while adults shelter in crevices and empty tests of Balanus perforatus, mainly below MTL. Settlement of males into barnacle tests appears to be random, but females show some degree of aggregation, perhaps to other females. Other species show the same change of habitat at sexual maturity and all inhabit intertidal or inshore localities.     

Carpospore release in a species of Polysiphonia

Intertidal algae from rockpools at different tidal heights, along with Laminaria holdfasts and samples of sublittoral algae were collected from both the sheltered and exposed side of Filey Brigg, North Yorkshire. Samples of sediments were also collected from MLWS on the sheltered shore. A total of 1091 individual ostracods, consisting of 32 species, from 20 genera and 12 families, were identified from 15 sites along the Brigg in July 1996. The current study lists the occurrence of thirteen species previously unrecorded for the Yorkshire coast, and confirms presence of three species that were thought to have a general distribution around the British Isles. The seven Paradoxostoma species showed distinct zonation patterns on both the sheltered and exposed shore. Paradoxostoma ensiforme and P. variabile were only found intertidally, P. hibernicum decreased numerically down shore, and P. bradyi and P. abbreviatum were only found in low shore, Laminaria holdfast or sublittoral samples. This pattern was also seen in many other species, e.g. Xestoleberis aurantia, which only occurred in the intertidal phytal samples, whereas others were only found sublittorally, e.g. Sclerochilus truncatus. Cytherois fischeri, Paradoxostoma robinhoodi, Hemicytherura cellulosa, Leptocythere psammophila, Semicytherura sella and Sclerochilus gewermuelleri were found on the exposed shore only and Cuneocythere semipunctata only occurred on the sheltered shore. Apart from these differences in distribution, the other species occurred on both sides of the Brigg, with only minor differences in density. Some species were more numerous on the sheltered shore (e.g. Heterocythereis albomaculata), whereas others occurred in higher frequencies on the exposed shore (e.g. P. hibernicum). However, there was no marked difference in assemblage structure between the sheltered and exposed side of Filey Brigg. The intertidal phytal assemblages then showed a high degree of similarity. However the sublittoral assemblages were markedly dissimilar from the high-shore assemblages and there was little similarity between the intertidal phytal and sediment assemblages. Although some species occurred in both habitats, e.g. Cythere lutea, others were only found in either one or the other. The phytal assemblages had a higher species richness of ostracods and were more diverse than the sediment assemblages. However, there was no correlation between phytal ostracod species diversity and tidal height, or between diversity and sediment content of the algae. The Yorkshire coast ostracod fauna is compared and contrasted with that previously described by other workers from southern and western Britain.     

Structure of insect community in the fungus Inonotus radiatus in riparian boreal forests

Basidiomes of polypore fungi host many insects. Yet systematic information about insect assemblages from most fungal species is lacking. We studied the insect community associated with the wood-decaying fungus Inonotus radiatus (Sowerby: Fr.) P. Karst. (Hymenochaetales). More specifically, we studied the effect of successional stage and weight of basidiomes, as well as shore exposition (north or south), on species richness and composition, as well as occurrence and abundance of the most abundant fungivores. Basidiomes were collected from riparian forests at five lakes in Sweden. Insects were reared out from the basidiomes in the laboratory. A total of 5645 adult insect individuals of 117 taxa were obtained. Among these, 2782 specimens of 36 taxa use Inonotus radiatus basidiomes as breeding habitat. Eight species of parasitic wasps were new to Sweden. The most abundant fungivore was Ennearthron cornutum (Ciidae), which is a generalist breeding in many polypore species. Based on our material and literature, the melandryid beetles Abdera affinis and A. flexuosa seem to be specialists on the order Hymenochaetales. Other frequent fungivores were Dorcatoma dresdensis (Ptinidae), and the lepidopterans Archinemapogon yildizae, Nemapogon cloacellus and N. picarellus (Tineidae). The parasitoid community associated with the tineid moths was similar to the community associated with the other polypore species in the order Polyporales. In contrast, the parasitoids associated with Dorcatoma (and/or Abdera) were different from the other Polyporales species, suggesting that the fungal host species is more important for these parasitoid species than the beetle host species itself. The most abundant and frequent parasitoids were the braconids Diospilus dispar and Colastes fritzeni, which both parasitise Dorcatoma. Species richness was significantly smaller in fresh than in more decayed basidiomes, but species composition did not differ. There was no difference in species composition or richness between north and south shorelines.     

Ectosymbionts of the non‐indigenous Asian shore crab,Hemigrapsus sanguineus (Decapoda: Varunidae), in the western north Atlantic,and a search for its parasites

Over 560 Asian shore crabs, Hemigrapsus sanguineus, collected mainly in the spring of 2005 and 2006 from rocky intertidal locations in southern New Jersey, were examined for epibionts. Small numbers of the sympatric green crab, Carcinus maenas, and the Atlantic mud crab, Panopeus herbstii, were examined for epifauna to compare with H. sanguineus. Blue mussel spat, Mytilus edulis, and the encrusting, cheilostome bryozoan, Conopeum tenuissimum, were the dominant ectosymbionts of the shore crab, with prevalences of 22.2 and 32.1%, respectively; ranges of intensity were 1–146 spat/crab and 1–31 colonies/crab. Both species are incidental symbionts. Larger crabs had higher prevalences and intensities of C. tenuissimum colonies, and these colonies displayed a distinct pattern of attachment to the carapace which seemed to be related to crab morphology and habitat. Much less common was the encrusting, ctenostome bryozoan Alcyonidium albescens, a facultative symbiont species with a prevalence of 3.4%. Other epibionts were the encrusting, cheilostome Membranipora tenuis, the tubicolous polychaetes Hydroides dianthus, Sabellaria vulgaris, and Spirorbis sp., the barnacles Balanus improvisus and Semibalanus balanoides, and unidentified thecate hydroids, all incidental symbionts with prevalences from 0.2 to 3.2%. The total number of known ectosymbionts of H. sanguineus, including additional species found previously in the USA and the western Pacific, is 13. Carcinus maenas and P. herbstii share some of the same symbionts. Rhizocephalan externae were not observed in any of the crab species used in this study, nor were gill parasites or internal parasites found among 248 specimens of H. sanguineus.     

Marine biodiversity on the Algerian Continental Shelf (Mediterranean Sea)

The Mediterranean Sea is known as a biodiversity hot spot, with 16,848 species reported. Biodiversity is higher in coastal areas and decreases with depth. However, knowledge about the southwestern sector remains scarce. For the last three decades, sampling of soft-bottom communities along the 1180 km of the shallow Algerian coast (0–136 m) has recorded 1642 macrobenthic species. There is a decreasing west–east species-richness gradient, especially for the total species richness and the amphipods. In addition, quantitative sampling in Bou Ismail Bay in summer 1988 (98 sampling sites for a total of 841 species) shows that diversity indices (i.e. species richness, >100 species for 0.2 m^?2; Shannon diversity, >6.0; and ES₅₀, >34) are among the highest for similar sand and muddy-fine sand communities in the Mediterranean Sea and the northeastern Atlantic Ocean. Bou Ismail Bay appears to have the highest species richness among Algerian bays, probably because of its variety of benthic habitats and the absence of significant pollution in this area. Monitoring must be undertaken to survey this high biodiversity, and a national strategy should be proposed to preserve high diversity zones.     

Soil oribatid mite (Acari: Oribatida) diversity and composition in semi-deciduous forest fragments in eastern Amazonia and comparison with the surrounding savanna matrix

We recorded species abundance and richness of oribatid mites along 16 plots established in semi-deciduous forest fragments in Amazonia. The results were compared with a published dataset consisting of an inventory carried out in 38 plots in the surrounding savanna. Totals of 143 and 91 species were recorded in the forest fragments and savanna, respectively. Sørensen similarity index between both environments was 0.44. Ordination of sites according to oribatid mite species composition showed a clear separation between forest fragments and savanna. Rostrozetes ovulum, Archegozetes longisetosus and Eohypochthonius (Eohypochthonius) becki were abundant and frequent in the forest fragments but exceedingly rare in the savanna. Neoppia (Neoppia) schauenbergi, Pseudoppia sp. C, Microppia sp. A and Cosmochthonius sp. A were limited to the savanna. This study also represents an early step toward knowing which groups of species are exclusive to one or another vegetation type or are sensitive to their inherent environmental conditions.     

Zoogeography and evolutionary ecology of the genus Platorchestia (Crustacea,Amphipoda, Talitridae)

ABSTRACT

Species of the genus Platorchestia occur both in the northern hemisphere (18 species) and southern hemisphere (three species plus a synanthropically introduced species in South America and South Africa). The greater number of endemic Platorchestia species in the North Pacific Ocean suggests that it could be the epicentre of evolution for this genus. North-western Pacific Platorchestia includes 15 species which occupy five ecotopes: wrack (seven species), terrestrial leaf litter (five species), freshwater (one species), marsh (one species) and tentatively present in caves (one species). North-eastern Pacific Platorchestia includes only one putative driftwood specialist, with no other species found in North American coastal habitats. This compares with three good endemic Platorchestia species (plus two putative additional species) and only two ecotopes: wrack (three species) and freshwater (two species) from the North Atlantic Ocean, inclusive of the Gulf of Mexico and Mediterranean Sea. Insufficient data is available to consider Platorchestia zoogeography for the Arabian Sea and Bay of Bengal. Synanthropic dispersal involving Platorchestia in Polynesian outrigger canoes, or in solid ballast carried in the holds of wooden sailing ships has been identified as a potential complicating factor in the zoogeography of this genus. Platorchestia is proposed to have arisen on Laurasia and is therefore basically a northern hemisphere genus. Questions concerning Platorchestia zoogeography and evolutionary ecology are posed and two methods (more intensive field sampling and molecular genetics) are suggested to be the way to solve them.     

Composition of meiobenthonic Platyhelminthes from brackish environments of the Galician and Cantabrian coasts of Spain with the description of a new species of Djeziraia (Polycystididae,Kalyptorhynchia)

From 1997 to 1999, the fauna of free‐living Platyhelminthes of the rias ecosystem was studied along the Galician and Cantabrian coast in northern Spain. In total, 72 platyhelminth species are listed in this study. Forty‐two species represent new records for the Iberian Peninsula, three of which represent new genera records. A new species belonging to the genus Djeziraia (Polycystididae, Kalyptorhynchia), Djeziraia longistyla sp. nov., is described in this paper. In this broad‐scale study, a large data set (27 localities) of the estuaries of northern Spain allowed an analysis of the turbellarian species assemblages and the relation of species distributions to salinity, conductivity, oxygen, temperature, and sediment characteristics. Species assemblages (species diversity) of each habitat of the brackish water ecotone are shown. The present study contributes to knowledge on the ability of adaptation of free‐living Platyhelminthes to regimes of brackish water ecotones.     

In search of the true Tydeus (Acari,Tydeidae)

The early history of the genus Tydeus, the type genus of the family Tydeidae, is complex and convoluted and, subsequently, even the identity of the type species of the family remains unclear. First, the literature is thoroughly analysed and morphological characters of some species are reappraised. After studying Oudemans' types, two species inquirendae, Tydeus croceus and T. cruciatus, are redescribed and a third, T. spathulatus, removed from synonymy and reinstated as a valid species. A fourth species, confused with T. spathulatus, is described. A lectotype is designated for T. spathulatus and a neotype for T. croceus. After discussion, the genus Lorryia Oudemans, is re‐established in its pristine state. As the redescribed species were designated as type species by Oudemans, the following new generic synonymies are proposed: Raphitydeus Thor, and Lorryia Oudemans, sensu Ka?mierski (, ) are junior synonyms of Brachytydeus Thor, ; Homeotydeus André, (partim) and Pseudolorryia Ka?mierski, are junior synonyms of Calotydeus Oudemans, ; Brachytydeus Thor, (partim), Calotydeus Oudemans, (partim), Tydeus Koch, sensu Oudemans, (partim), Orthotydeus André, , and Tydeus Koch, sensu Ka?mierski, are junior synonyms of Tydeus Koch, . To stabilize the usage of the names, especially that of the genus type of the family Tydeidae, the International Commission of Zoological Nomenclature will be asked to set aside all previous type species designations for Tydeus and to designate Tydeus spathulatus as the type species, with Oudemans' specimens from Italy as primary type material.     

Parasite community of the golden cownose ray Rhinoptera steindachneri Evermann and Jenkins 1891 (Chondrichthyes: Myliobatidae), in Acapulco Bay,Guerrero, Mexico

The parasite community of the ray Rhinoptera steindachneri from Acapulco Bay was examined and quantified; analyses were based on the sex of the host and the date of sampling. A total of 171 specimens of R. steindachneri were examined during July–August of 2010, and May and July of 2012. Twenty-one species of parasites were found: three species of Monogenea; eight adult and one larval species of Cestoda; one larval species of Nematoda; five species of Copepoda; two species of Isopoda; and one species of Hirudinea. Cestodes had the greatest species richness (43% of the total species), followed by the copepods (24%). Two species of cestode, Glyphobothrium sp. and Rhinebothrium sp., were collected only from adult rays. At the component community level, species richness showed statistically significant variation between 13 and 16 species, which is similar to previous reports for other species of rays. The parasite component communities and infracommunities of R. steindachneri exhibited similar patterns: high species number and low numerical dominance by a particular species of parasite. The differences of body size of male vs. female rays, and a change in diet and feeding behaviour with the age of R. steindachneri, are likely important factors in the structuring of their parasite communities.     

Three new species of the brackish‐water copepod Halicyclops (Crustacea,Cyclopoida) from Ariake Bay,Japan

Three new species of the cyclopoid copepod Halicyclops are described from river estuaries of Ariake Bay, Japan. Halicyclops continentalis sp. nov. is most similar to H. laminifer, but differs by the shape of an angular protuberance on the genital double‐somite and a serrate hyaline frill of the fourth urosomite. Halicyclops sinensis described by Tai and Chen is widely distributed in China and is identifiable to H. continentalis, indicating that the population in Ariake Bay is probably a continental relict. Halicyclops uncus sp. nov., belonging to the thermophilus group, is distinguishable by the shape of the lateral process on the genital double‐somite, a frill of the fourth urosomite and caudal rami; it is probably endemic to Japan. Halicyclops ariakensis sp. nov. differs from the other congeners by a combination of the shape of the prosome, urosomal hyaline frills and caudal ramus length; it is considered endemic to Ariake Bay.     

Water mites of the genus Hygrobates Koch, 1837 (Acari: Parasitengona: Hygrobatidae) from Hokkaido,northern Japan

Nine species of Hygrobates (Acari: Parasitengona: Hygrobatidae) from Hokkaido, Japan are described or redescribed from newly collected material and historical specimens. Treated herein are eight species in the subgenus Hygrobates, including one new species, H. bibi sp. nov., as well as H. calliger Piersig, ; H. foreli (Lebert, ); H. japonicus Uchida, ; H. longipalpis (Hermann, ); H. longiporus Thor, ; H. nigromaculatus Lebert, ; and H. sokolowi Thor, . Also treated is H. ezoensis Uchida, in the subgenus Rivobates. A lectotype and paralectotype are designated for H. japonicus Uchida, . Hygrobates (s. str.) heteropalpis Imamura, is synonymized with H. calliger Piersig, . The name H. ezoensis Uchida, is resurrected from synonymy with H. diversiporus Sokolow, . Six species previously known from Hokkaido were collected in the study: H. foreli, H. japonicus, H. longipalpis, H. longiporus, H. diversiporus, and H. ezoensis. New records for both Hokkaido and Japan include H. nigromaculatus and H. sokolowi. A species previously recorded from Hokkaido, H. taniguchii Imamura, , was not found in this study. Three new characters are proposed as useful for the taxonomy of the genus Hygrobates: the ratio of the distance between the P‐4 ventral setae to P‐4 length, the ratio of the length of the longest terminal seta on IV‐L‐5 to the length of IV‐L‐5, and the nature of the outer border of the genital plates.     

Rhynchocoel vessel in Cephalotrichidae (Nemertea: Palaeonemertea)

The morphology of the rhynchocoel blood vessel was studied in 26 specimens representing 14 species of the family Cephalotrichidae. In eight specimens the vascular system could not be traced because of their small size, poor fixation, or contraction during fixation. In the other 18 specimens, a short mid-dorsal rhynchocoel vessel was found. In Cephalothrix adriatica, C. hongkongiensis, C. kefersteini, C. oestrymnica, C. orientalis, C. rufifrons, C. cf. fasciculus and C. cf. simula, the mid-dorsal rhynchocoel vessel penetrates the dorsal side of the proboscis insertion, and extends backward abutting the mid-dorsal rhynchocoel wall (Type A). In C. filiformis sensu Iwata (1954 Iwata, F. 1954. The fauna of Akkeshi Bay. XX. Nemertini in Hokkaido. J Fac Sci Hokkaido Univ Ser VI, Zool., 12: 1–39.  [Google Scholar]), the vessel is pendant in the rhynchocoel above the proboscis (Type B). In C. filiformis s.str., the vessel runs in the proboscis wall, after passing through the proboscis insertion (Type C). Morphology of the rhynchocoelic vessel might have taxonomic significance in cephalothrichids.