Myxidium macrocheili n. sp. (Cnidospora: Myxidiidae) from the Largescale Sucker Catostomus macrocheilus Girard,and a Synopsis of the Myxidium of North American Freshwater Vertebrates*

SYNOPSIS. Myxidium macrocheili n. sp. is described from the gall bladder, bile and pancreatic ducts of Catostomus macrocheilus Girard (largescale sucker) in western Montana. This parasite is markedly host specific; the trophozoite is nonmotile, polysporous, spheroidal, elongated or irregular, often arched and rolled at the edges, and up to 2.5 mm in greatest length; the ecto- and endoplasm are distinct; the sporonts are disporoblastic. The bipolar spore is longitudinally striated, usually ellipsoidal in front view, slightly S-shaped in side view, and averages 11.7 × 6.6 × 6.3 μ; the suture line and ridge are distinct; the polar filaments are coiled 4–6 times. An illustrated synopsis and a key of the 19 species and 10 unnamed forms of Myxidium of North American freshwater vertebrates are presented. At present members of the genus are known to infect fishes, amphibians and a single species of reptile on this continent.     

Haemogregarina pseudemydis n. sp. (Apicomplexa: Haemogregarinidae) and Pirhemocyton chelonarum n. sp. in Turtles from Louisiana*

SYNOPSIS. The blood of each of 95 turtles (8 species) collected from southeastern Louisiana was infected with some or all of the merogonic stages and gametocyte stage of Haemogregarina pseudemydis n. sp. Five species of turtles harbored Pirhemocyton chelonarum n. sp. Turtle Haemogregarina and Pirhemocyton are locality records for Louisiana. Pirhemocyton is reported for the first time in turtles and in the continental U.S.A.     

Myxidium lesminteri n. sp. (Myxosporea: Myxidiidae) from the gall-bladder of three southern African Anura

During 1988 and 1989 409 specimens, representing 50 species in 9 families of southern African Anura from 26 localities throughout the Republic of South Africa and from Swaziland, were examined for gallbladder myxozoans. Myxidium lesminteri n. sp. was the only myxozoan found and was observed in one tomopterna krugerensis (Ranidae), one Bufo garmani (Bufonidae) and one Heleophryne natalensis (Heleophrynidae), all from Transvaal. The spore of Myxidium lesminteri (9.5–15.0 × 5.0–8.0 m) is characterised by a smooth shell devoid of striations but has one longitudinal ridge.     

A new species of Myxidium (Cnidaria: Myxosporea: Myxidiidae) from the gallbladder of pickerels,Esox spp. (Esociformes: Esocidae), from southwestern Arkansas,USA

Systematic Parasitology - During April 2016 and again in November 2021, four Chain Pickerels, Esox niger were collected from Union (n = 3) and Nevada (n = 1) counties, Arkansas, USA, and 65 Grass...     

Redescription of Plutomurus kelasuricus Martynova, 1969 (Collembola: Tomoceridae) from Georgian caves

The collembolan species Plutomurus kelasuricus Martynova, 1969 Martynova, E. (1969): Springtails of the family Tomoceridae (Collembola) from the fauna of the USSR [in Russian]. Entomological Review, 43, 299–314. [Google Scholar] is redescribed and illustrated based on material sampled in Georgian caves. Differences from the morphologically similar P. abchasicus Martynova, 1969 Martynova, E. (1969): Springtails of the family Tomoceridae (Collembola) from the fauna of the USSR [in Russian]. Entomological Review, 43, 299–314. [Google Scholar] are discussed. A key to species of the genus Plutomurus found in the Caucasus is provided.     

Description of Myxidium pseudocuneiforme n. sp. (Myxosporea: Myxidiidae) from Cyprinus carpio in China,with the resolution on a taxonomic dilemma of Myxidium cuneiforme

Investigations on myxozoan parasites of fish from Chongqing in China, revealed two Myxidium cuneiforme-like myxosporeans infecting the gallbladder of Cyprinus carpio carpio and Carassius auratus. We researched their myxospore morphology, and analyzed their genetic similarity and phylogenic relationships to other myxozoans based on small subunit ribosomal DNA (18S rDNA) sequences. Although both parasites recovered were morphologically similar, the myxosporean isolated from C. auratus was consistent in morphology to Myxidium cuneiforme, which was described from this host species. The parasite isolated from C. c. carpio had overlapping myxospore dimensions to M. cuneiforme, but on average, the polar capsules were not as long. More importantly, this parasite was genetically distinct from M. cuneiforme with 96.3% and 96.5% similarity in two sequences of 18S rDNA, and we propose the name Myxidium pseudocuneiforme n. sp. for this myxozoan from common carp. Its mature myxospores are ellipsoidal and asymmetric with pointed ends in valvular view, arc-shaped or fusiform in sutural view. The pyriform polar capsules are equal in size, and polar filament with 5–6 coils. This study highlights that molecular characteristics and host specificity are indispensable for myxozoan species identification when presented with the taxonomic dilemma of whether we are observing one species that exhibits slight morphological differences or multiple, but similar, species in different hosts.     

楔形两极虫(黏体门,双壳目)的形态学重描述及其近缘种的分子系统学研究

两极虫属Myxidium和楚克拉虫属Zschokklella在形态上非常相似,形态鉴定界限模糊。为进一步厘清两者的分类学关系,本研究对采自涪江重庆市潼南县江段的楔形两极虫M.cuneiforme Fujita,1924进行了形态学重描述,并对其分子系统学进行了研究。楔形两极虫孢子壳面观呈长条形,中部稍凹陷或孢子一边突出,壳瓣上有6~8条与缝嵴平行的条纹;缝嵴直,缝面观呈梭形。孢子长12.5μm±0.3μm,宽5.4μm±0.3μm(n=20)。极囊2个,呈梨形,分布于孢子两极端;极囊长4.3μm±0.2μm,宽3.1μm±0.2μm(n=20),极丝细长且明显,盘曲5~6圈。以18S rDNA为分子标记,对楔形两极虫及其近缘种进行了保守区变异、遗传距离、序列相似度和分子系统发育分析,结果表明:两极虫属和楚克拉虫属均非单系发生,两属间物种相互交叉聚支;两极虫属与楚克拉虫属物种间具有很近的亲缘关系。本文基于形态和分子数据的研究结果支持将两极虫属和楚克拉虫属合并为一个属的观点。     

Eurycea bislineata (Green), the Two-Lined Salamander, a New Host of Myxidium serotinum Kudo & Sprague, 1940 (Myxosporida, Myxidiidae)

SYNOPSIS. Myxidium serotinum was found in 51 of 58 (87.9%) specimens of the two-lined salamander, Eurycea bislineata , from West Virginia. This constitutes a new host record. No specimens of the order Salientia, or other species of the order Caudata were infected. Eurycea bislineata appears to be the normal host of M. serotinum , which is specific for the gallbladder in a variety of amphibian hosts. Apparently, larval E. bislineata becomes infected with M. serotinum , and the parasite does not become a mature trophozoite until after the tadpoles metamorphose to the adult salamander. Certain host hormonal factors may be important to the maturation of M. serotinum.     

Myxosporeans (Cnidospora: Myxosporea) of Antarctic fishes

Data on 13 species of fish myxosporeans from the Antarctic part of the Atlantic Ocean is present. Among them, 8 new species are described: Zschokkella australis sp. n., Davisia nototheniae sp. n., Ceratomyxa orthospora sp. n., C. ellipsoidea sp. n., C. antarctica sp. n., Leptotheca ampla sp. n., Pseudalataspora squamifrons sp. n., P. meridionalis sp. n.). Four species were found for the first time in the region and four species were found in new hosts.     

Redescription of Neoamphorophora ledi (Wahlgren, 1938) (Hemiptera: Aphididae) from Japan

Apterous viviparous females of Neoamphorophora ledi (Wahlgren, 1938) living on Rhododendron degronianum Carr. (Ericaceae) on Honshu island, Japan, are redescribed and the hitherto unknown alate viviparous females are here described. Rhododendron degronianum is a new host plant species for this aphid. This species is recorded for aphid fauna of Eastern Palearctic for the first time. Keys to species of Neoamphorophora based on apterous and alate viviparous females are given. A key to aphid genera with swollen siphunculi living on species of Rhododendron worldwide based on apterous viviparous females is also provided.     

A new planktic species of Pseudanabaena (Cyanoprokaryota, Oscillatoriales) from North American large lakes

A new species of Pseudanabaena (Cyanoprokaryota, Oscillatoriales) from the plankton of North American large lakes is documented, with ecological and distributional data. This taxon differs from previously described Pseudanabaena species with respect to a characteristic undulating and coiling filament structure. Pseudanabaena contorta spec. nova appears to be specific to large North American Great Lakes with a drainage basin that is not totally Precambrian shield. Recently, it has been found as a consistent but minor component of the planktic cyanoprokaryote populations during the spring and summer months in Lake Superior and Lake Ontario. Comparisons are made with other common species of this genus as well as another undulating morphotype of the genus Glaucospira, that could possibly result in confusion, found in other large Alberta and northern Saskatchewan lakes.     

A thermal denaturation study of genomic DNAs from North American minnows (Cyprinidae: Teleostei)

Base compositions and differential melting rate profiles of genomic DNAs from twenty species of North American cyprinid fishes were generated via thermal denaturation. Base pair composition expressed as % GC values ranged among the twenty species from 36.1–41.3%. This range is considerably broader than that observed at comparable taxonomic levels in other vertebrate groups. Both the range and average difference in base pair composition between species in the diverse and rapidly evolving genus Notropis were considerably greater than those between species in other North American cyprinid genera. This may indicate that genomic changes at the level of base pair composition are frequent and possibly important events in cyprinid evolution. Compositional heterogeneity and asymmetry values among the twenty species were uniform and low, respectively, suggesting that most of the species lacked DNA components in their genomes which differed substantially from their main-band DNAs in base pair composition. The melting rate profiles revealed a prominent and distinct heavy or GC-rich DNA component in the genomes of three species belonging to the subgenus Cyprinella of Notropis. These and other data suggest that the heavy melting component may reflect a large, comparatively GC-rich family of highly repeated or satellite DNA sequences common to all three genomes.     

A Redescription of Rhabdalestes tangensis (Lönnberg) (Pisces, Characidae) from East Africa

Rhabdalestes tangensis (Lönnberg, 1907), a small African characin, is redescribed on the basis of new material from the Pangani River Basin in northern Tanzania. The morphometric and meristic variations described encompass those of R. leleupi Poll, 1967.     

Redescription of Branchinecta granulosa Daday, 1902 from Argentina (Crustacea: Branchiopoda)

The species Branchinecta granulosa Daday 1902, is redescribed on the basis of adult material from near Facundo (Chubut Province, Argentina). Its relationship to its regional congeners is outlined.