A detailed cytogeographic and morphometric study of the Asplenium trichomanes group in the Czech Republic is presented. We detected diploid (2n = 72), tetraploid (2n = 144) and hybrid triploid plants (2n = 108). Based on the morphometric study, four intraspecific taxa are recognized. These taxa correspond to the four subspecies of A. trichomanes (A. t.subsp. trichomanes, <I.A. t. subsp. quadrivalens, A. t. subsp. pachyrachis and A. t. subsp. hastatum) distinguished in the floras of western, southern and northern Europe. Triploid plants were determined as A. t. nothosubsp. lusaticum (A. t. subsp. trichomanes × A. t. subsp. quadrivalens). The individual morphological characters used for determining subspecies are evaluated and a determination key presented.
Morphometric variation in Aphanius iberus was analysed to demostrate the remarkable genetic divergence between Mediterranean and Atlantic population of Iberia. Four discrete morphotypes in males and three in females were distinguished. Morphometric data discriminated the Atlantic and Mediterranean populations, but revealed the Villena population as the morphologically most differentiated. Atlantic populations were described as a new species, Aphanius baeticus sp. nov., which differs from A. iberus in the overall shape, coloration pattern and number of branched rays on the dorsal and anal fins. The Villena population was retained in A. iberus because, despite of its morphological differentiation, show high genetic introgression at the nuclear genome with neighbouring populations. The range of A. baeticus sp. nov. is restricted to the eight localities of the Atlantic slope of the Iberian Peninsula. This new species should be considered Critically Endangered (CR) according to the IUCN Red List Categories.
Myxobolus buckei sp. n. is described from the spinal column of Leuciscus cephalus (L.), Rutilus rutilus (L.) and Abramis brama (L.) from freshwater rivers in the North of England. The plasmodia develop within the remnants of the embryonic notochord in the intervertebral spaces. The spores are large, measuring (in µm) 14.0 ± 0.7 × 11.5 ± 0.6 (mean ± SD), smooth, round to ellipsoid in valvular view with several sutural edge markings. The polar capsules are pyriform and of equal size, measuring 7.5 ± 0.5 × 4.2 ± 0.2 (mean ± SD), with 11-12 turns of the polar filament arranged perpendicularly to the longitudinal axis of the polar capsule. The parasite has a large intercapsular appendix and large iodinophorous vacuole. The parasite can be differentiated from all known species of Myxobolus Bütschli, 1882 by a combination of the morphological characters defined. Infected fish show marked longitudinal compression of the body compared to uninfected individuals of the same year class, a feature which is pathognomonic for the disease. Histologically, host responses ranged from mild hypertrophy of the zygapophyseal process and expansion of the intervertebral membrane to complete hypertrophy and fusion of the vertebrae. Prominent notochord is present in the intervertebral spaces of infected fish and sporogony of the parasite leads to a vigorous focal inflammatory response involving proliferating fibroblast and osteogenic cells. The parasite causes a radial expansion of the centra and extensive dorsal and ventral outgrowths of the vertebrae leading to compression of the spinal cord and blood vessels running through the neural and haemal spines respectively. The parasite is considered highly pathogenic to juvenile cyprinids.
Fieldwork was conducted in 1998 and 1999 in the Okavango River and Delta and a total of 275 fishes representing 31 species were examined for the presence of myxosporean parasites. A total of seven myxosporeans of the genus Myxobolus Bütschli, 1882 were found infecting the fishes. Two new species namely Myxobolus etsatsaensis sp. n. from Barbus thamalakanensis Fowler, 1935 and M. paludinosus sp. n. from Barbus paludinosus Peters, 1852 are described. Myxobolus africanus Fomena, Bouix et Birgi, 1985, M. camerounensis Fomena, Marqués et Bouix, 1993, M. hydrocyni Kostoïngue et Toguebaye, 1994, M. nyongana (Fomena, Bouix et Birgi, 1985) and M. tilapiae Abolarin, 1974 are recorded for the first time in Botswana and descriptions of these species are provided.
A list of myxozoan genera is presented in the current taxonomical scheme. These genera are defined; their type species and most important pathogens along with their hosts are listed. Simultaneously, definitions of actinospore stages representing sexual stages of the myxosporean life cycle are given; altogether, 17 actinospore collective groups with 180 types have been described. Life cycles of the two classes of the phylum Myxozoa, Malacosporea and Myxosporea, are briefly outlined with specification of the appropriate terms. Up to now, 4 malacosporean and 2,180 myxosporean species assigned to a total of 62 genera, have been established. The surviving classification of myxosporeans, based on spore morphology, is discussed in the context of the still fragmentary data resulting from SSU rDNA sequence analyses. The main task for the future is a rigorous, detailed morphological description combined with molecular techniques in establishment of new species and in revision of the existing ones. Establishment of a classification acceptable from morphological, biological and phylogenetical viewpoints is necessary.
During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.
The genus Maxvachonia Chabaud et Brygoo, 1960 (Ascaridomorpha: Cosmocercidae) is a poorly known group of parasitic nematodes. Species of Maxvachonia are native to Madagascar-Australo-Papuan Region, where they are known to parasitise frogs, snakes and skinks. Unfortunately, most of Maxvachonia species have been inadequately described. In the present study, we report the native species Maxvachonia chabaudi Mawson, 1972 from the intestine of the invasive marine toad Rhinella marina (Linnaeus) in Australia for the first time. We speculate that the marine toads infected with M. chabaudi are likely related to their eating skinks or the similarity in diet/habitat/ecology between the toad and the skinks. The detailed morphology of M. chabaudi was studied using light microscopy and, for the first time, scanning electron microscopy, based on the newly collected specimens. Some characters important for the specific diagnosis of M. chabaudi are reported for the first time, including each lip with distinct inner flanges, the location of vulva varying from anterior to posterior of the oesophageal bulb and the presence of single medio-ventral precloacal papilla. An identification key to the species of Maxvachonia is provided.
Gyrodactylidae and Dactylogyridae (Monogenoidea) are described or reported from three species of Characidium Reinhardt (Crenuchidae), small species of Characiformes, from streams located in southern Brazilian states. Gyrodactylus carolinae sp. n. (Gyrodactylidae) is described from the body surface of Characidium lanei Travassos (type host), C. pterostictum Gomez, and Characidium sp. from streams in the states of Paraná and São Paulo. This new species closely resembles species of Gyrodactylus von Nordmann, 1832 described from species of Poeciliidae, from which it differs by the morphology of the hooks and nucleotide sequences of ITS1-5.8S-ITS2 rDNA. Gyrodactylus inesperatus sp. n. is described from the body surface of Characidium sp. from a stream in the State of São Paulo. The latter new species is characterised by lacking a shield on the superficial bar and by the morphology of the hooks, both unique characteristics for Neotropical species of Gyrodactylus. Marumbius gen. n. (Dactylogyridae) is proposed to accommodate two species, M. dorsivaginatus sp. n. from the gills of Characidium pterostictum (type host) and C. lanei, and M. amplexus sp. n. from the gills of C. lanei (all from the state of Paraná). Both species are characterised by having dorsal vagina, hook pairs 2-4, 6 and 7 composed by two subunits, hook pairs 1 and 5 lacking proximal subunit, and by the length of proximal subunits (when present) varying among hook pairs, completely or partially overlapping gonads, and male copulatory organ (MCO) represented by an incomplete coil of a sclerotized tube articulated to the accessory piece by a copulatory ligament. Cacatuocotyle paranaensis Boeger, Domingues et Kritsky, 1997 is reported from C. lanei at low prevalence in the Rio Marumbi (state of Paraná). The Monogenoidea that parasitize species of Characidium are members of several independent lineages, some of distant evolutionary relationships, suggesting a complex origin for this parasitic fauna.
Based on molecular markers (COII and ITS1-ITS2) and morphological data, we describe three new Neotropical species of Gyrodactylus von Nordmann, 1832 from Scleromystax barbatus (Quoy et Gaimard) and Scleromystax macropterus (Regan) from southern Brazil. The three new species can be distinguished from each other by sequences of both molecular markers and morphology of hooks and anchors. Gyrodactylus bueni sp. n. is characterised by having hook with shaft curved, heel straight, shelf straight, toe pointed, anchor with superficial root slender, elongate and male copulatory organ armed with two rows of spinelets. Gyrodactylus major sp. n. presents hook with shaft, point curved, proximal shaft straight, heel convex, shelf convex, toe concave, anchor with superficial root robust and male copulatory organ armed with two rows of spinelets. Gyrodactylus scleromystaci sp. n. presents hook with shaft, point recurved, heel convex, shelf convex, toe pointed, anchor with superficial root curved and male copulatory organ armed with two rows of spinelets. These species appear to be closely related to other species of Gyrodactylus known from other species of Callichthyidae. These new species, however, differ by the comparative morphology of the haptoral hard structures and molecular data. Comparative analysis of sequences from these species of Gyrodactylus suggests that the COII gene may represent an important marker for the taxonomy of species of Gyrodactylidae and, perhaps, for species of other lineages of Monogenoidea.
New information is provided on the distribution of 19 species of lichens belonging to the genus Caloplaca (Teloschistales) in the Czech Republic. Six species are new to this country: C. epithallina, C. erodens, C. inconnexa, C. phlogina, C. polycarpa and C. thuringiaca. The species C. albolutescens, C. cerinella, C. chlorina, C. chrysodeta, C. dichroa, C. flavocitrina, C. herbidella and C. marmorata are reported from the Czech Republic, but little is known about their distribution in this country. Caloplaca biatorina, C. obliterans, C. rubelliana, and C. xantholyta are rediscovered after more than 50 years. The presence of Caloplaca crenulatella, recently reported as new to this country, is confirmed and is actually one of the most common species of this genus. Ecological and chorological data are given for each species, and taxonomic and nomenclatural notes for C. albolutescens and C. chlorina are amended.