Canningia spinidentis gen. et sp. n. infects the fir bark beetle Pityokteines spinidens Rtt. in Austria. The pathogen attacks mainly the fat body, Malpighian tubules, the muscles and the connective tissue of larvae and adults, and the gonads of adults. The development is haplokaryotic, with single spores. Spores are short tubular, uninucleate, with globular anchoring disc inserted subapically, laterally, in a depression of the endospore wall. Polar filament is isofilar, with 5/6 coils. Polaroplast is composed of two lamellar parts of different density. A new genus Canningia gen. n. is proposed based on differences in ultrastmc-tures of spores from Unikaryon Canning, Barker, Hammond et Nicholas, 1974.
A new microsporidium was observed in the flying fish Cypselurus pinnatibarbatus japonicus (Franz) (Exocoetidae) from Yakushima, Japan. Visual examination revealed the microsporidium to form white elongate nodules in the host's trunk muscle. Monomorphic spores were ovoid to pyriform in shape, with average dimensions of 4.1 × 2.2 µm and possessing a polar tube describing 13-15 coils. Histological observations showed that each parasite focus of infection was encapsulated by a host-produced fibrous membrane. The presence of sporophorous vesicles was not clearly determined. Ribosomal DNA sequence analyses showed the microsporidium to be discrete from other known fish muscle-infecting species and to be most closely related to a clade comprising the Pleistophoridae and Glugea spp. The parasite is provisionally placed as Microsporidium cypselurus sp. n.
The ultrastructural cytology and reproduction of Amphiacantha longa Caullery et Mesnil, 1914 is described. Mcrogonial reproduction was not observed. The sporogony follows two lines: free disporoblastic. and enveloped, polysporoblastic, involving sporoblast mother cells. The enveloped sporogony is endogenous in spore sacs of sporont origin, daughter cells are formed by vacuolation. Probably all stages have coupled nuclei. Both free and enveloped spores are equipped with an extrusion apparatus composed of a flat polar sac, a straight polar filament of manubrium type, and a posterior globular appendix. Manubrium and appendix are enclosed in a membraneous coat. Circular elements of coat material occur in the proximity of the extrusion apparatus. The membraneous coat and the surface layer of the manubrium penetrate the polar sac. The extrusion apparatus is located at the wide pole of the spore, the nuclei at the narrower pole. Hosts are gregarines of the genus Lecudina Mingazzini, living in the gut of the polychaete Lumbrinereis fragilis (O. F. Muller). The cytology and reproduction are discussed and compared to other genera of metchnikovellideans, to the chytridiopsid genera, and to microsporidia expressing the typical cytology for the group. Metchnikovellideans and chytridiopsids exhibit cytological and reproductive similarities. The species is redescribed, the diagnosis of the genus Amphiacantha Caullery et Mesnil, 1914 is emended, and the new family Amphiacanthidae, comprising the genera Amphiacantha and Amphiamblys Caullery et Mesnil, 1914, is established.
Unikaryon montanum sp, n. infects the fat body, muscle, Malpighian tubules and ovaries of adult Ips typographus L. The development is haplokaryotic, with separate nuclei during the schizogony and sporogony. Sporonts have the cellular envelope with added layer of electron dense material. Two types of spores are formed: small broad-oval primary spores, 1.5 x 1.0 pm, with warty surface of spore wall, uninucleate, with isofilar polar filament in 5/6 coils and elongated-oval environmental spores, 0.8-1 x 2 pm, with warty spore wall attenuated at the anterior end, uninucleate, with spore polar filament in 8 coils. Both types have a dual polaroplast with the anterior part of a layer of confluent fine lamellae ending posteriorly in bulbous processes, and posterior part composed of coil of tubules.