The rate of development and longevity of the monogenean skin parasite Entobdella soleae

Using soles (Solea solea) infected experimentally with oncomiracidia of the monogenean skin parasite Entobdella soleae, it was found that the parasite begins to assemble eggs at about 85 days post infection and may survive for as long as 6 1/2 months at 12 +/- 1 degrees C. Growth of the anterior hamuli continues throughout life but the growth rate decreases with time. The oldest (largest) parasites recovered from laboratory soles were similar in size to the largest parasites collected in the wild.     

The mode of hatching of the monogenean Entobdella soleae, a skin parasite of the common sole (Solea solea).

Observations have been made on the hatching behaviour of the larva of the monogenean Entobdella soleae and on the effects of various enzymes on the opercular cement of the egg. These observations indicate that hatching is brought about by a proteolytic hatching fluid which is produced by two pairs of ventral head glands and spread over the inner surface of the opercular joint by rotation of the larva about its longitudinal axis. After hatching there is no trace of the ventral head glands. Similar glands are present before hatching in the oncomiracidium of E. hippoglossi.     

Spermatogenesis in a monogenean, Diclidophora merlangi.

Halton D. W. &; Hardcastle A. 1976. Spermatogenesis in a monogenean, Diclidophora merlangi. International Journal for Parasitology6: 43–53. Development of the spermatozoa in the testis of a polyopisthocotylean fish-gill fluke, Diclidophora merlangi, has been examined by light and electron microscopy. Spermatogonial cells are typically undifferentiated and display numerous free ribosomes and relatively little cytoplasm. Successive mitotic divisions produce spermatocytes which are characterized by expansion of the ER and the development of Golgi complexes. Nuclear division is followed by incomplete cytokinesis so that spermatocytes and subsequent stages are joined and develop syncytially. Nuclear synaptonemal complexes mark the first division of the meiotic phase, the second giving rise to a rosette of 32 spermatids. During spermateleosis, the spermatid nucleus condenses and migrates into a conical-shaped projection of cytoplasm. A centriole-like structure and basal bodies, anchored by a pair of attached rootlets, produce axial filaments that grow out from the spermatid and eventually fuse with the nuclear projection. Spermatozoa are then released from the residual cytoplasm. Each spermatozoon is approximately 325 μm in length and 2 μm maximum diameter and in section shows a nucleus, mitochondrion, paired axial units which conform to the “9 +1” pattern described for other platylelminthes, particles of β-glycogen, and a line of micro-tubules around the inner aspect of the limiting membrane.     

First monogenean flatworm from a microhylid frog host: Kankana, a new polystome genus from Madagascar

Kankana manampoka n. gen., n. sp. (Monogenea, Polystomatidae), is described from the urinary bladder of the narrow-mouthed frog Platypelis pollicaris. This is the first record of a polystome from the Microhylidae and the third polystome genus from Madagascar, next to Metapolystoma and Madapolystoma. The extensive uterus and presence of hamuli resemble Metapolystoma but the vitellarium confined to the lateral fields in Kankana is different. Madapolystoma also has an extensive uterus but contain only up to 32 advanced developed larvae. Based on the extensive uterus filling the body proper and the vitellarium confined to two lateral fields posterior in the body this new polystome resembles Eupolystoma known from Africa and India. However, unlike Eupolystoma, the gonads are in the middle of the body, vaginae are lacking and a pair of hamuli is present. A molecular phylogenetic analysis of concatenated 18S and 28S ribosomal RNA gene sequences supplemented by genetic distances inferred from 28S and COI sequences showed that this new genus is more related to Madapolystoma, a genus only reported from Madagascar, than to Eupolystoma known from Africa and India and Metapolystoma known from Africa and Madagascar.     

A catalogue of the nominal species of the monogenean genus Dactylogyrus Diesing, 1850 and their host genera

Dactylogyrus is the largest helminth genus, with more than 900 nominal species, and is consequently in a state of considerable confusion. In an attempt to consolidate our knowledge of this large taxon, this work surveys the nominal species and catalogues them and their hosts (to the generic level) in the form of a species list which is cross-referenced to host-parasite list. A reference list to the authorities for the taxa is included.     

Revision of the monogenean subfamily Thoracocotylinae Price, 1936 (Polyopisthocotylea: Thoracocotylidae), with the description of a new species of the genus Pseudothoracocotyla Yamaguti, 1963

Members of the subfamily Thoracocotylinae are gastrocotylid monogeneans of Spanish mackerels (scombrid fishes of the genus Scomberomorus) from warm to warm-temperate seas around the world. We revise the diagnosis of the subfamily and recognise two genera and three species as valid. The genus Paradawesia Bravo Hollis & Lamothe Argumedo, 1976 is synonymised with Thoracocotyle MacCallum, 1913, and Dawesia Unnithan, 1965 and Methoracocotyle Lebedev, 1984 are synonymised with Pseudothoracocotyla Yamaguti, 1963. Thoracocotyle crocea MacCallum, 1913 (syns T. paradoxica Meserve, 1938 and Paradawesia bychowskyi Bravo Hollis & Lamothe Argumedo, 1976) is recorded from two species of Scomberomorus in the eastern Pacific (California to Peru) and four in the western Atlantic (South Carolina to Brazil). Pseudothoracocotyla ovalis (Tripathi, 1956) Yamaguti, 1963 (new syns Dawesia indica Unnithan, 1965, D. incisa Lebedev, 1970, Methoracocotyle scomberomori (Young, 1968) Lebedev, 1984, M. gigantica (Rohde, 1976) Lebedev, 1984 and Thoracotyle indica (Unnithan, 1965) Murugesh, 1995) is recorded from the gills of seven species of Scomberomorus from the Indo-west Pacific (eastern South Africa north to the Persian Gulf, and east to Fiji). Pseudothoracocotyla whittingtoni n. sp. is described from an eighth Indo-west Pacific scomberomorid, S. munroi, in Australian waters.     

Effects of salinity and food quality on the growth of sub-adult mysids of Tenagomysis spp.: a laboratory study

In estuaries, the somatic growth of crustacean mysids may be influenced by spatio-temporal variation in salinity and food resources. We tested such a possibility in a laboratory experiment, where somatic growth of sub-adult mysids Tenagomysis chiltoni and Tenagomysis novaezealandiae was studied in intermediate salinities(10–20) with contrasting high or low (based on Carbon and Nitrogen richness) food qualities. Different salinity and/or food quality combinations interacted to produce contrasting growth trajectories between the two species. Growth of sub-adult T. chiltoni was more influenced by salinity, whereas the growth of T. novaezealandiae more strongly affected by food quality. Our results suggest that small environmental changes to salinity and food regimes may give rise to different growth trajectories among sub-adult mysids which may have a cascading influence on their life histories and patterns of coexistence with other species in small intermittently open/closed estuaries in temperate regions.     

Quadriacanthus aegypticus n. sp., a monogenean gill parasite from the Egyptian teleost Clarias lazera

Summary Quadriacanthus aegypticus n. sp., a monogenean from the gills of Clarias lazera inhabiting Nile delta waters in Egypt, is described. The genus Quadriacanthus Paperna, 1961 is reported for the first time in Egypt. Particular attention has been paid to the reproductive system, the digestive system, the anterior adhesive glands, the posterior body glands and haptoral sclerites. Possible functions of the different internal organs are discussed. The diagnosis of the genus Quadriacanthus is emended. ac]19840926