Pseudalataspora vanderlingeni n. sp. (Myxosporea: Bivalvulida) from gall bladders of the Cape hakes Merluccius capensis Castelnau, and M. paradoxus Franca (Teleostei: Merlucciidae).

A new species of myxosporean parasite is described from the gall bladders of the hakes Merluccius capensis Castelnau and M. paradoxus Franca (Pisces: Teleostei) caught off the west and south coasts of South Africa. The new species, Pseudalataspora vanderlingeni, is described morphologically and molecularly and compared with the 15 other species of Pseudalataspora previously described from marine fish. Although a molecular description is available on GenBank for only one of these 15 species, the morphological description supports the status of P. vanderlingeni as a new species. Earlier reports, without detailed descriptions, of Leptotheca sp. and Ceratomyxa sp. from the same hosts caught off Namibia were very likely to have been of P. vanderlingeni. These earlier studies reported high prevalences of infection, similar to those of >60% described in the present study. The effects of fixation and freezing on the dimensions of spores of Pseudalataspora spp. are described, and the status of the genus Pseudalataspora within the family Ceratomyxidae is discussed.

"Candidatus Gortzia shahrazadis", a Novel Endosymbiont of Paramecium multimicronucleatum and a Revision of the Biogeographical Distribution of Holospora-Like Bacteria.

Holospora spp. and "Candidatus Gortzia infectiva", known as Holospora-like bacteria (HLB), are commonly found as nuclear endosymbionts of ciliates, especially the Paramecium genus. HLB are related by phylogenetic relationships, morphological features, and life-cycles, which involve two alternating morphotypes: reproductive and infectious forms (RF, IF). In this paper we describe a novel species belonging to the "Ca. Gortzia" genus, detected in P. multimicronucleatum, a ciliate for which infection by an HLB has not been reported, discovered in India. This novel endosymbiont shows unusual and surprising features with respect to other HLB, such as large variations in IF morphology and the occasional ability to reproduce in the host cytoplasm. We propose the name of "Candidatus Gortzia shahrazadis" for this novel HLB. Moreover, we report two additional species of HLB from Indian Paramecium populations: "Ca. Gortzia infectiva" (from P. jenningsi), and H. obtusa (from P. caudatum); the latter is the first record of Holospora from a tropical country. Although tropical, we retrieved H. obtusa at an elevation of 706 m corresponding to a moderate climate not unlike conditions where Holospora are normally found, suggesting the genus Holospora does exist in tropical countries, but restricted to higher elevations.

Synopsis of the species of Thelohanellus Kudo, 1933 (Myxozoa: Myxosporea: Bivalvulida).

A synopsis of the species of Thelohanellus Kudo, 1933 (Myxozoa: Myxosporea: Myxobolidae) is presented. It includes a total of 108 nominal species. For each species, the most relevant morphological and morphometric characteristics are provided, together with data on the type-host and locality, the site of infection within the host and the original references.

Two new species of myxosporean parasites (Myxosporea: Bivalvulida) from gall bladders of Macruronus magellanicus Lönnberg, 1907 (Teleostei: Merlucciidae).

Two new species of myxosporeans are described from the gall bladders of hoki, Macruronus magellanicus Lönnberg, 1907, caught in the Southeast Pacific off Chile and in the Southwest Atlantic off the Falkland Islands. Pseudalataspora kovalevae n. sp. is described morphologically and genetically. Of the 12 species of Pseudalataspora previously described from the gall bladders of marine fish, P. kovalevae is most similar in morphology to P. umbraculiformis Gaevskaya and Kovaleva, 1984. The 18S rRNA gene sequence from P. kovalevae is the first for a member of the genus Pseudalataspora. Based on currently available myxosporean 18S rRNA gene sequence data, P. kovalevae shares greatest sequence identity with species of the genus Ceratomyxa (C. anko and C. pantherini). Palliatus magellanicus n. sp. is described morphologically only; it differs considerably in morphology, host species and locality from the five other Palliatus species described from marine fishes. A third species from the gall bladder is also described morphologically and genetically. On the basis of its morphology it is tentatively identified as Myxidium baueri Kovaleva and Gaevskaya, 1982, for which M. magellanicus is a new host record. Molecular analysis indicates that, of those species for which data are available, M. baueri is most closely related to Myxidium coryphaenoideum Noble, 1966 based on 18S rRNA gene sequence data, though support for a phylogenetic grouping is low.