Characterization of a diversity of tetraphyllidean and rhinebothriidean cestode larval types, with comments on host associations and life-cycles.

Invasive Non-Native Crustacean Symbionts: Diversity and Impact

Antarctic krill, Euphausia superba were collected by use of the plankton nets in Antarctic Ocean by a catcher boat of Taiyo-Gygyo K.K. The localities, number and size of Antarctic krill examined are shown in Table 1. The krill were immediately stored at -40°C on the boat. These frozen samples were brought in our laboratory. The krill were pressed between two glass plates, and were inspected by the binocular dissecting microscope ( 1 Ox) against the parasites.

On the examination against the parasites of antarctic krill euphausia superba

A new genus and species of symbiotic, semi-parasitic nemertean worm, Ovicides julieae n. gen., n. sp., is described from the xanthid crabs Chlorodiella nigra and C. xishaensis. The new genus possesses accessory stylet pouches and exhibits simultaneous hermaphroditism, features new to the family Carcinonemertidae. The new species has a relatively small anterior proboscis chamber and small basis, yet it possesses the largest stylet to basis ratio (up to 0.650) reported for the family. It also has a flame cell pattern of at least 2[(3+3)], which is different from those reported for two other species. The worm occurred in a lightly granulated sheath on the abdominal sterna, pleopods, and clutches of its host, but few adult worms were found. The species exhibited a high host specificity and was more frequently found on C. nigra than on C. xishaensis (7.5 vs. 0.4%, overall prevalence, respectively). Worms were only found on female crabs, and worm intensity showed a modest but significantly positive correlation with host size. Ovicides julieae represents the second genus in the Carcinonemertidae, the fifth described carcinonemertid species from Australia, and the eleventh described species in the family.

Ovicides julieae n. gen., n. sp. (nemertea: carcinonemertidae) on xanthid crabs from the great barrier reef, australia

New collections were made of Ditrachybothridium macrocephalum Rees, 1959 from the deep-sea elasmobranchs Apristurus laurussonii (Saemundsson) and cf. Rajellabigelowi (Stehmann) in the northern Atlantic Ocean, allowing studies of the morphology of its plerocercus. The material has also allowed an estimate of its position within the Diphyllidea inferred from molecular data for the first time. The plerocercus is withdrawn, but not invaginated, within a cyst with a thick vacuolated wall. The encysted strobila is distinct, with several putative segments and advanced genital anlagen, and the scolex is fully developed with a distinct apical pad. 28S rDNA (D1-D3 regions) sequences were generated from both encysted and excysted D. macrocephalum, as well as from other diphyllidean and pseudophyllidean (outgroup) taxa for use in phylogenetic analyses. Maximum parsimony and Bayesian inference analyses both showed that the diphyllidean genus Echinobothrium is paraphyletic without inclusion of the only two other diphyllidean genera, Ditrachybothridium Rees, 1959 and Macrobothridium Khalil & Abdul-Salam, 1989. A list of published records of larval diphyllideans, their hosts and localities is included.

/pdf/the-plerocercus-of-ditrachybothridium-macrocephalum-rees-2f3f9k434u.pdf

The plerocercus of Ditrachybothridium macrocephalum Rees, 1959 from two deep-sea elasmobranchs, with a molecular analysis of its position within the order Diphyllidea and a checklist of the hosts of larval diphyllideans.

Les Crustaces Decapodes Brachyoures sont parasites par des Helminthes, notamment par des Nemertes et des larves de Cestodes.Les larves de Cestodes appartenant a trois ordres differents (Tetrarhyncha, Tetraphyllidea, et Diphyllidea ) ont pour hotes intermediaires des Decapodes. Sept especes de Brachyoures sont pour la premiere fois signalees comme hotes de ces formes larvaires.Le Nemerte Carcinonemertes carcinophila a ete recolte chez trois genres de Crabes ou il etait inconnu.

/pdf/study-of-crustacea-decapoda-brachyura-parasites-nemertinea-5gjfeqi3dt.pdf

Christian P. Vivares

Papers

[Study of Crustacea Decapoda Brachyura parasites: Nemertinea and larval Cestoda].