On Schistosoma curassoni,S. haematobium and S. bovis from Senegal: development in Mesocricetus auratus,compatibility with species of Bulinus and their enzymes

A comparative study on the development of Senegalese isolates of Schistosoma curassoni, S. haematobium and S. bovis in hamsters is reported, together with the compatibility of these parasites with Bulinus spp. and enzymes of adult worms.

The mean worm return from 35 hamsters exposed to 100 cercariae each of S. curassoni was 11·5%, and of these 54% were paired, the remainder were single males. The growth and maturation of the worms were recorded from 40 to 100 days. The cross-over point (when paired females are of the same length as paired males) was reached at 42 days post-infection when the worms averaged 13·7 mm in length. The majority of tissue eggs (84·5%) were recovered from the liver, compared with 11% in the colon, 2·5% in the caecum and 1·6% in the small intestine. Estimates of the fecundity of paired females averaged 167 eggs/day per female worm. Snail-infection experiments showed S. curassoni to be compatible with B. umbilicatus, marginally compatible with B. senegalensis and incompatible with B. forskalii, B. jousseaumei and B. guernei. S. curassoni is marginally compatible with B. bavayi, B. beccarii, B. camerunensis and B. cernicus, (members of the B. forskalii group) and B. obtusispira, a species placed in the B. africanus group. The mean worm return from 35 hamsters exposed to 100 cercariae each of S. haematobium was 9·1%, and of these 46·7% were paired, 42·1% were single male worms and the remaining 11·2% were single female worms. The growth of the worms was recorded from 40 to 100 days, the maturation from 60 to 100 days. The cross-over point was reached at about 62 days post-infection when the worms averaged 8·3 mm long. The majority of tissue eggs (95·3%) was recovered from the liver, compared with 2·8% and 1·9% from the small intestine and colon, respectively. Estimates showed that the average fecundity of paired females was 86 eggs/day per female worm. Snail-infection experiments showed that S. haematobium is marginally compatible with B. senegalensis, but incompatible with B. guernei and B. forskalii. The mean worm return from 35 hamsters exposed to 100 cercariae each of S. bovis was 26·6%, and of these 53·1% were paired, the remainder were single males. The growth and maturation of worms were recorded from 40 to 100 days. The cross-over point was reached just before 40 days: at 40 days the paired males averaged 9·5 mm in length, the paired female 9·6 mm in length. The majority of eggs (53·1%) was recovered from the liver, compared with 20·7% from the small intestine and 19·8% from the colon.

Estimates of the fecundity of paired females averaged 95 eggs/day per female worm. Snail-infection experiments showed S. bovis to be compatible with B. guernei, fairly compatible with B. forskalii, and marginally compatible with B. umbilicatus. B. senegalensis appeared to be sensitive to S. bovis under laboratory conditions with large numbers dying after one week of exposure.

Enzymes in 3017 extracts of adult schistosomes, obtained from natural and laboratory infections, have been analysed by isoelectric focusing. Enzymes studied include glucose 6-phosphate dehydrogenase (G6PDH), phosphoglucomutase (PGM), lactate dehydrogenase (LDH), acid phosphatase (AcP), malate dehydrogenase (MDH), hexokinase (HK) and glucose phosphate isomerase (GPI). S. bovis was clearly differentiated from S. haematobium by patterns of G6PDH, GPI, HK and AcP. Similarly, S. bovis and S. curassoni were distinguishable by the different patterns of PGM, GPI, HK and AcP. S. haematobium and S. curassoni were differentiated by patterns of PGM and HK. Heterogeneity was seen in all species. In a natural infection of a sheep S. bovis and S. curassoni were found paired together.     

New species of Copidognathinae (Acari: Halacaridae) from southern Africa

Three new species of Copidognathinae (Acari: Halacaridae) are described from the eastern coast of southern Africa (Mozambique; South Africa: Eastern Cape and KwaZulu-Natal). Copidognathus caloglossae sp. nov. and Acarothrix umgenica sp. nov. were collected in mangrove habitats, whereas Copidognathus xaixaiensis sp. nov. was collected on a rocky shore. Acarothrix umgenica represents the first record of the genus Acarothrix Bartsch, 1990 from the African continent.     

Schistosoma curassoni Brumpt, 1931 in sheep and goats in Senegal

A survey of 5722 sheep and 1752 goats at the abatoir in Dakar, Senegal showed that the overall prevalence of schistosomiasis was 2·1%. Of the 112 animals where identification of the schistosome species was possible, all were infected with Schistosoma curassoni, and 2·7% had mixed infections with S. bovis. The adult worms of S. curassoni are described, and on the basis of egg morphology this species is shown to be distinct from S. bovis and S. mattheei. Eggs of S. curassoni measured 146 μm ± 16·8 × 63·3 μm ± 4·5 from sheep and 149·4 μm ± 13·2 × 62·8 μm ± 4·9 from mouse liver, and appear to be indistinguishable from the eggs of S. haematobium Guede Chantier, Senegal which measure 153·1 μm ± 11·1 × 62·4 μm ± 12·1 from mouse liver. However, S. curassoni differs from S. haematobium in that it develops more quickly than S. haematobium in hamsters, uterine eggs becoming visible at least 20 days earlier; the adult worms of S. curassoni are nearly double the size of S. haematobium in hamsters at 70 days post infection.

Also, S. curassoni develops well in sheep and cattle unlike S. haematobium, but will not develop to maturity in baboons like S. haematobium.     

Distributions of two ectosymbionts,branchiobdellidans (Annelida: Clitellata) and scutariellids (Platyhelminthes: “Turbellaria”: Temnocephalida), on atyid shrimp (Arthropoda: Crustacea) in southeast China

Distribution of two ecologically similar but usually spatially separate ectosymbionts, branchiobdellidans (Annelida) and scutariellids (Platyhelminthes), on atyid shrimp (Neocaridina spp.) is reported from 18 localities in five Provinces of southeastern China. Prevalence was determined for the branchiobdellidan, Holtodrilus truncatus, found at seven locations, the scutariellid, Scutariella japonica, present at every site, and where cohabitation occurred. Both ectosymbionts showed a microhabitat predilection for the host's branchial chambers and instances of cohabitation occurred at all seven locations where H. truncatus were collected, although not on every shrimp. On-site observations of live hosts supporting both ectosymbionts showed that neither H. truncatus nor S. japonica reacted aggressively or defensively towards the other when in close proximity. Instances of imported Chinese Neocaridina spp. into central Honshu Island, Japan, almost certainly came from areas in southeast China identified in this study. These imported populations are predicted to spread northwards into the area where endemic Japanese branchiobdellidans occur.     

Revision and biogeographical analysis of the black-chinned tilapia Sarotherodon melanotheron (Teleostei,Cichlidae): results of morphometric,allozyme, globin chain and mtDNA studies

Morphometric, allozyme, globin chain and cytochrome b analyses were used for a revision of the subspecies complex of the black-chinned tilapia, Sarotherodon melanotheron Rüppell, 1852. Three out of four subspecies are recognized as valid: S. m. melanotheron (Ivory Coast to Benin), S. m. heudelotii (Senegal to Guinea) and S. m. leonensis (Sierra Leone to Liberia). The fourth subspecies, S. m. nigripinnis, is raised to the species level S. nigripinnis and is composed of the nominate subspecies S. n. nigripinnis known from Gabon and a newly introduced subspecies, S. n. dolloi, originally described as Tilapia dolloi and previously synonymized with S. m. nigripinnis. It is presently known from the mouth of the Congo to the Lower Kouilou. Phylogenetically, populations from the most eastern range, e.g. Gabon/Congo, are considered to represent the most ancient populations. From this area of origin, the western range of West Africa (Senegal to Benin) was colonized. Two independent colonization events are indicated by allozyme and mtDNA analyses. The initial invasion of the western range of West Africa could be dated back to about 2.5 million years ago.     

Notes on Simulium ovazzae Grenier and Mouchet (Diptera: Simuliidae) and river crabs (Malacostraca: Potamidae) and their association

Summary

Collections of crabs in the forest zone of West Cameroon produced three species—Potamonautes africanus, P. orthostylis and P. pobeguini. The P. africanus carried populations of immature Simulium ovazzae.

Analysis of crabs collected by hand and those collected in traps indicates very little overlap in the sizes of the crabs obtained by the two techniques. This problem is discussed.

The infestation rates of S. ovazzae on P. africanus were found to be highest on medium-sized crabs. The attachment sites of the S. ovazzae on the crabs were found to vary with both the size of the crab and the size of the Simulium larva.

The size distributions of S. ovazzae larvae on small crabs were found to be different from those on medium and large crabs. The characteristic deficiency of smaller larvae on medium and large crabs reported for other crab-phoretic species was also found with S. ovazzae but the smaller crabs showed a deficiency of larger larvae. A hypothesis is put forward to explain the dearth of larger larvae on the smaller crabs and the higher infestation rate on medium crabs.

S. ovazzae are shown to arrive on their hosts as single larvae carried by the current.

Six adult S. ovazzae were reared from pupae in the laboratory. Small numbers of presumed S. ovazzae biting man in Cameroon are reported.     

XLI.—Records of some parasitic worms from British vertebrates

Summary

The percentage infection with fifteen species of larval Digenea is described in ten species of littoral prosobranchs in Cardigan Bay.

In some host species percentage infection varies with the position on the shore in relation to the height above chart datum and to exposure to wave action.

These variations are attributed, partly to the behaviour of the host species, to the effects of environmental conditions on the susceptibility to infection of the first intermediate host and on the free-living stages of the parasite and to the physiological or genetical resistance of the first intermediate host.     

The occurrence of Podocotyle atomon (Rud., 1802)(Digenea), Bothriocephalus scorpii (Müller, 1776) (Cestoda), Contracaecum clavatum (Rud., 1809) (Nematoda) and Echinorhynchus gadi Zoega,in Müller, 1776 (Acanthocephala) in the five-bearded rockling,Onos mustelus (L.)

Summary

The variation in the incidence and intensity of infestation of the five-bearded rockling, Onos mustelus (L.) with Podocotyle atomon, Bothriocephalus scorpii, Contracaecum clavatum and Echinorhynchus gadi has been studied for a period of one year, on a shore at Mumbles Head, Swansea.

There is a general increase in the incidence and intensity of infestation by P. atomon and C. clavatum with increase in the length (age) of the host. With E. gadi and B. scorpii, however, infestation decreases in the larger fish.

The seasonal variations in the incidence and intensity of infestation with these parasites are influenced by tidal fluctuations, temperature and by the feeding habits and breeding cycle of the fish.

The frequency distribution of parasite specimens is also described and discussed.     

A new species of stoloniferous octocoral (Cnidaria: Alcyonacea) from the south-western Indian Ocean

A new species of stolonate octocoral referable to the genus Scleranthelia Studer, 1878 (family Clavulariidae), is described from the East London and Durban regions of South Africa. The species is frequently encountered by dredge at depths ranging from 85 to 340 m. Scleranthelia thomsoni sp. nov. has been confused with the northern Atlantic species S. rugosa (Pourtalés, 1867) (= S. musiva Studer, 1878) by previous authors, but a comparison of material representing both species has shown them to be distinctly differentiated.     

Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay,Hokkaido, Japan

We found 39 cheilostome species among more than 7000 specimens collected at 10 intertidal sites in rocky habitats along the shore of Akkeshi Bay, eastern Hokkaido Island, Japan. These species are herein described in detail and illustrated by scanning electron microscopy. Nine species (23% of total) are described as new (Electra asiatica, Callopora sarae, Conopeum nakanosum, Cauloramphus cryptoarmatus, Cauloramphus multispinosus, Cauloramphus niger, Stomachetosella decorata, Microporella luellae, and Celleporina minima), and 21 species (54%) are reported for the first time from Japan. Species richness ranged from eight to 29 species per study site. A TWINSPAN analysis showed the species fell into nine groups defined by the local pattern of distribution. A cluster analysis of study sites based on similarity of species composition showed three faunistic groups distributed geographically: in Akkeshi Lake, along the eastern‐central shore of the bay, and at the mouth of the bay. Species richness in estuarine Akkeshi Lake was low, with a species composition very different from the outer bay. Most cheilostomes were found on rock and shell substrata, but uncommonly occurred on concrete walls, algae, hydroids, tubes of polychaetes, other bryozoans, and anthropogenic debris. Of the 39 species found, 33 (85%) contained embryos during the collecting periods, 2–7 June and 3–6 July 2004. The biogeographical composition of intertidal cheilostomes at Akkeshi Bay included species with Arctic‐Boreal (28%), Boreal (59%), and Boreal‐Subtropical (13%) distributions. The overall species richness of intertidal cheilostomes was two‐thirds that documented intertidally in a comparable study at Kodiak, Alaska, a locality 15° higher in latitude. We attribute the lower richness at Akkeshi to differences in the nearshore marine environment between the two localities.     

Two new species of lithobiid centipedes and the first record of Lamyctes africanus Porath (Chilopoda: Lithobiomorpha) in China

Two new species of lithobiid centipedes (Hessebius prospinosa sp. nov. and Lithobius (Ezembius) maqinensis sp. nov.) and the first record of Lamyctes africanus Porath which are all females, suggesting parthenogenesis, are described based on specimens from the Qinghai-Tibet Plateau. Keys for each of the Chinese species of Hessebius, Ezembius and Lamyctes are presented. Phylogenetic analysis using a fragment (613 bp) of mitochondrial cytochrome c oxidase subunit I (COI) indicates that (1) Lithobius (Ezembius) maqinensis sp. nov. clades with L. (E.) giganteus Sseliwanoff, and (2) the specimens of Lamyctes africanus Porath from China clade with L. africanus Porath from other countries.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:24364A2D-8D84-444D-9CFC-24336A211D2B     

A new species of Schizopera (Copepoda: Harpacticoida) from Japan,its phylogeny based on the mtCOI gene and comments on the genus Schizoperopsis

The predominantly marine genus Schizopera Sars, 1905 has only two significant inland water species-flocks, one in the ancient African Lake Tanganyika and the other in subterranean waters of Western Australia. Discovery of Schizopera abei sp. nov. from several interstitial locations in the vicinity of the ancient Lake Biwa has wider implications for the study of morphological homoplasies in the genus, as well as for the study of freshwater invasions in harpacticoid copepods. The new Schizopera species belongs to a small group of congeners with a two-segmented endopod of the fourth leg, which used to be recognised as a separate genus, Schizoperopsis Apostolov, 1982. Our reconstructed phylogenies based on the mtCOI partial sequences suggest that this character probably evolved convergently in at least some Schizopera, thus rendering the genus Schizoperopsis polyphyletic. However, almost all basal nodes in our cladograms are weakly supported, which shows limitations of a single-gene approach for reconstructing phylogenetic relationships. The new species is the first member of its genus from Japanese inland waters, and it has no close relatives among extent congeners anywhere in the world. We speculate that its ancestor may have invaded Lake Biwa, and subsequently its surrounding subterranean waters, from brackish areas around central Japan, presumably during a period of high sea water level through its major outflow river. This discovery may provide further support for the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats.

http://zoobank.org/urn:lsid:zoobank.org:pub:1F71F7AD-B7C8-4AD3-BE44-5E1BEE4E2AA8     

Infestation by the freshwater cymothoid Artystone trysibia Schioedte (Crustacea,Isopoda): parasite and host behaviour

To observe the behaviour of cymothoid isopods during the infestation process, 30 experiments in aquaria were carried out, using the fish Gymnogeophagus gymnogenys (Hensel, 1870) and Jenynsia multidentata (Jenyns, 1842) as hosts, and Artystone trysibia Schioedte, 1866 as the parasite. All the specimens were collected from Guaíba Lake in Porto Alegre, Rio Grande do Sul. We recorded and analysed the behavioural acts of the parasites and hosts from the moment of encounter to the infestation, which was considered to be completed when the parasite had inserted itself into the fish's body. The behavioural acts are shown as a flow diagram, including the frequencies of occurrence of each act. Positive infestation occurred in 60% of the experiments. No relationship was observed between the sizes of the parasite and host, and the success of the infestation.     

An investigation into the metazoan parasites of the spiny dogfish (Squalus acanthias L.), off the west coast of Ireland

The present study was undertaken to examine the parasite fauna of spiny dogfish, and to determine seasonal variations in infection rates and faunal composition. A total of 10 metazoan parasite species was recorded, of which four species occurred in the intestine, three species were parasitic on the gills, two species occurred on the skin, and one species parasitized the spiracle. However, a cumulative parasite species richness curve indicated that a larger sample may have yielded additional parasite species. The parasite assemblage consisted of five species of copepods (Eudactylina acanthii Scott, Caligus curtis Müller, Pandarus bicolor Leach, Echthrogaleus coleoptratus (Guerin-Meneville) and Pseudocharopinus bicaudatus (Krøyer)), two species of nematodes (Anisakis simplex Rudolphi and Hysterothylacium aduncum (Rudolphi)), two species of cestodes (Trilocularia gracilis Olssen and Gilguina squali (Fabricius)), and one species of monogenean (Erpocotyle abbreviata (Olssen)). The parasite fauna was found to be similar to that of S. acanthias from the North Sea, and from New Zealand waters. Results obtained during the present study indicate that the infection rates of certain parasite species display seasonal cycles, most species displaying their greatest prevalence in spring and their lowest prevalence in autumn.     

Analysis of enzymes in the Bulinus tropicus/truncatus complex (Mollusca: Planorbidae)

Summary

Five enzymes in the crude digestive gland extracts of individual snails of the B. tropicus/truncatus complex have been analysed by isoelectric focusing in polyacrylamide gels. The enzymes studied were: malate dehydrogenase (MDH); phosphoglucomutase (PGM); glucosephosphate isomerase (GPI); acid phosphatase (AcP) and hydroxybutyrate dehydrogenase (HBDH). Snails from 103 population samples (52 diploid, 51 tetraploid) from diverse geographical origins have been studied. Diploid and tetraploid snails were clearly differentiated and regional distributions of certain enzyme types are reported. The taxonomic implications of the findings are discussed.