Caudal Process Research Articles

Magnetic resonance image findings in pug dogs with thoracolumbar myelopathy and concurrent caudal articular process dysplasia

BackgroundA retrospective case series study was undertaken to describe the magnetic resonance imaging (MRI) findings in Pug dogs with thoracolumbar myelopathy and concurrent caudal articular process (CAP) dysplasia. Electronic clinical records were searched for Pug dogs who underwent MRI for the investigation of a T3-L3 spinal cord segment disease with subsequent confirmation of CAP dysplasia with computed tomography between January 2013 and June 2017. Clinical parameters age, gender, neuter status, body weight, urinary or faecal incontinence, severity and duration of clinical signs were recorded. MRI abnormalities were described. Univariable non-parametric tests investigated the association between the clinical parameters and evidence of extra- or intra-dural spinal cord compression on MRI.Results18 Pug dogs were included. The median age was 106 months with median duration of clinical signs 5 months. All presented with variable severity of spastic paraparesis and ataxia; 50% suffered urinary/faecal incontinence. In all cases, MRI revealed a focal increase in T2-weighted signal intensity within the spinal cord at an intervertebral level where bilateral CAP dysplasia was present; this was bilateral aplasia in all but one case, which had one aplastic and one severely hypoplastic CAP. MRI lesions were associated with spinal cord compression in all but one case; intervertebral disc protrusion resulted in extra-dural compression in 10 (56%) cases; intra-dural compression was associated with a suspected arachnoid diverticulum in 4 (22%) cases and suspected pia-arachnoid fibrosis in 3 cases (17%). There was no association between clinical parameters and a diagnosis of intra-dural vs extra-dural compression. CAP dysplasia occurred at multiple levels in the T10–13 region with bilateral aplasia at T11–12 most often associated with corresponding spinal cord lesions on MRI.ConclusionsAll Pugs dogs in this study were presented for chronic progressive ambulatory paraparesis; incontinence was commonly reported. Although intervertebral disc disease was the most common radiologic diagnosis, intra-dural compression associated with arachnoid diverticulae/fibrosis was also common. Bilateral CAP aplasia was present in all but one Pug dog at the level of MRI detectable spinal cord lesions. A causal relationship between CAP dysplasia and causes of thoracolumbar myelopathy is speculated but is not confirmed by this study.

An early and new member of Balaenopteridae from the upper Miocene of Hokkaido, Japan

The family Balaenopteridae includes the modern blue whale, which is the largest animal on Earth. Our knowledge of the early members of Balaenopteridae, especially during the late Miocene and earlier periods, has recently increased, but this family is still poorly understood. A fossil balaenopterid (including the frontals, squamosals, parietals, vomer, pterygoid, basisphenoid, basioccipital, exoccipitals, right periotic and presternum) from the lower part of the Horokaoshirarika Formation, late Miocene (6.5–6.8 Ma) of Hokkaido, Japan is named as a new genus and species Miobalaenoptera numataensis, and is placed in a phylogenetic context. As a result, Miobalaenoptera numataensis is placed among the stem balaenopterids. The periotic of Miobalaenoptera numataensis shows a deeper suprameatal fossa and a shorter caudal tympanic process than extant species, incipient lateral tuberosity and a sharp anteroposteriorly long ridge on the ventral side of the anterior process. Miobalaenoptera numataensis adds information on the early morphology of the family including the periotic.http://zoobank.org/urn:lsid:zoobank.org:pub:EBAAD222-1F4C-492B-A75C-74DD3B36EE62

Skin nodules associated with parasitism with Henneguya sp. (Cnidaria: Myxosporea) in the neotropical fish Cyphocharax modestus

A new myxozoan species, Henneguya sp., is described based on material from skin of Cyphocharax modestus. Mature myxospores are were elongate and ellipsoidal, measuring 21.4 ± 1.2 (19.4–23.2) μm in total length, 5.1 ± 0.3 (4.5–5.8) μm in width, 11.9 ± 0.5 (10.9–12.7) μm in body length and 9.6 ± 0.7 (8.4–10.5) μm in length of the caudal process. The polar capsules were elongated and had unequal sizes, with length of 5.1 ± 0.4 (4.5–6.0) μm and 5.6 ± 0.4 (4.9–6.3) μm for smaller and larger respectively and width of 1.8 ± 0.2 (1.4–2.0) μm. The larger polar capsule had 8 turns in polar filament while the smaller polar capsule had 5 turns in polar filament. The macroscopic analysis revealed the presence of large nodules, which were located before and after the dorsal fin of the hosts. The histopathological analysis showed the development of nodules filled with plasmodia, surrounded by loose connective tissue, developed in the dermis of the skin. Many cysts containing countless spores, as well as free spores, were located in the dermis and hypodermis of the hosts, causing the disorganization of the connective tissue that is responsible for the support. This is the first record of a Henneguya species in C. modestus.

Morphological and phylogenetic characterization of a novel Unicauda species, infecting the kidney of Astyanax altiparanae (Teleostei: Characidae) in Brazil.

During a parasitological survey of Astyanax altiparanae captured in the Mogi Guaçú river, Pirassununga, state of São Paulo, Brazil, a new species of myxozoa was observed infecting the kidney of 30 of 42 specimens. Plasmodia of the new myxozoa, referred to herein as Unicauda whippsi n. sp. were spherical and varied from 450 to 1000 μm in length. The mature spore was elongated and measured 11 ± 1.2 (10-12) μm long by 5.4 ± 0.6 (4.7-7.2) μm wide. Polar capsules of unequal length with the filament coiled 7-9 times and a unique caudal process characteristic of the genus Unicauda, were recorded. Phylogenetic analysis demonstrated that U. whippsi n. sp. clustered with members of the genus Unicauda and Myxobolus, confirming it's placement within the family Myxobolidae. This is the first record of a species of Unicauda infecting characiform fish, as well as the first registered occurrence of species of this genus in South America.

Designation of a new family group name, Tonzidae fam. nov., for the genus Tonza (Lepidoptera, Yponomeutoidea), based on immature stages of Tonza citrorrhoa

The systematic position of Tonza Walker, 1864 is re-evaluated, based on the characteristics of immature stages and DNA barcodes. Larvae and pupae of Tonza citrorrhoa Meyrick, 1905 are described and illustrated for the first time. Larvae of this species form a loose web among the leaves and branches of the host plant, Putranjiva matsumurae Koidz. (Putranjivaceae Endl.). The immature stages of Tonza exhibit four unique apomorphies including: in the larva, the prolegs on A5 and A6 absent, and the seta L2 on the A1–A8 very small; in the pupa, four minute knobs are positioned in the middle portion on abdominal segments V and VI; while its caudal processes possess a W-shaped spine with numerous minute spines. These characteristics clearly distinguish Tonza from other yponomeutoid families and hence, we propose a new family group name, Tonzidae Kobayashi & Sohn fam. nov., for the genus Tonza. Existing DNA barcode data suggest a relationship with Glyphipterigidae Stainton, 1854. The family level status of Tonzidae fam. nov. provides a hypothesis that needs to be tested with larger molecular data.

Further revision of the genus Bythotrephes Leydig (Crustacea: Cladocera: Onychopoda): redescription of B. brevimanus Lilljeborg, reevaluation of B. cederströmii Schödler, and description of a new species of the genus.

Two species of the genus Bythotrephes Leydig, B. brevimanus Lilljeborg and B. cederstrӧmii Schӧdler, are analysed. The former of them is redescribed on the basis of type material and other materials from Northern Europe while the latter one is reevaluated, in comparison with the previous recent investigation which was based on limited material being not enough for the adequate species assessment. The species under consideration were investigated with the application of detailed morphological analysis, including intra- and interpopulation variability and the original scheme of morphometric measurements. The lectotype and paralectotypes of B. brevimanus were selected. Both species are characterized by considerable morphological variability which was especially prominent in taxonomically important features, such as structure and armament of thoracic limbs of first pair (tl I), caudal process, and claws of postabdomen and caudal process. It was concluded that the taxonomic identification of such variable units like B. brevimanus, B. cederstrӧmii and hybrid forms close to the latter species should be based only on comparison of sets of specimens of particular populations; the usage of single specimens can lead to incorrect results. Pedogenesis, in B. brevimanus and in family Cercopagididae in general, was recorded and described for the first time.A new species, B. lilljeborgi, is described based on material from Southern Sweden and Norway. It differs from the closely related species B. longimanus and B. brevimanus in number and size of claws of postabdomen and caudal process.The ranges of the above considered species overlap, especially prominently in North-Western Europe where all three species under consideration co-occur. B. brevimanus dominates in the Circumbaltic region and eastward through Central European Russia and the Ural Mountain region, possibly to the Yenisei River which requires further confirmation. B. cederstrӧmii is distributed further to the east, being recorded in Central Yakutia (Eastern Siberia). Data on co-occurrence of Bythotrephes species are limited and not always adequate because identification of taxa was often confused. Based on the information contained in the present paper, in particular the reevaluation of B. cederstrӧmii taxonomy, it may be suggested that both interspecific hybrid forms and B. cederstrӧmii s. str. could have invaded North American inland waters.

New myxosporeans parasitizing Phractocephalus hemioliopterus from Brazil: morphology, ultrastructure and SSU-rDNA sequencing.

Myxozoans are a diverse group of parasitic cnidarians, with some species recognized as serious pathogens to their hosts. The present study describes 2 new myxobolid species (Myxobolus figueirae sp. nov. and Henneguya santarenensis sp. nov.) infecting skin and gill filaments of the Amazonian pimelodid fish Phractocephalus hemioliopterus, based on ultrastructural, histology and phylogenetic analysis. The fish were caught in the Amazon River, Pará, Brazil. The plasmodial development of M. figueirae sp. nov. was in the dermis and those of H. santarenensis sp. nov. were of the intralamellar type. For both species, the plasmodia were surrounded by a connective tissue layer, but there was no inflammatory infiltrate. For M. figueirae sp. nov., mature spores were ovoid measuring 9.1 to 10 (9.5 ± 0.3) µm in length, 5.8 to 6.9 (6.4 ± 0.3) µm in width and 4.4 to 4.5 (4.5 ± 0.1) µm in thickness. Two polar capsules were elongated and of unequal size. For H. santarenensis sp. nov., mature spores were ellipsoidal in the frontal view, measuring 26.3 to 36.1 (31.9 ± 3) µm in total length, 9.6 to 11.9 (10.8 ± 0.5) µm in body length, 3.7 to 4.9 (4.3 ± 0.3) µm in width and 16.6 to 25.6 (21 ± 3.1) µm in caudal process. The polar capsules were elongated and of equal size. Phylogenetic analysis, based on partial small subunit ribosomal DNA (SSU rDNA) sequences and using the closest myxozoan sequences to each one of the species studied here based on previous GenBank data, showed M. figueirae sp. nov. and H. santarenensis sp. nov. clustering in distinct lineages. While H. santarenensis sp. nov. clustered in a well-supported subclade composed of Henneguya species that infect gills of South American pimelodid hosts, M. figueirae sp. nov. clustered in a weakly supported subclade containing parasite species of bryconid hosts.

Phacus multifacies sp. nov., a new Euglenophyceae from the State of Rio Grande do Sul, Southern Brazil

ABSTRACT As a result of the taxonomic survey of the pigmented Euglenophyceae of Lago da Ponte, an artificial pond located at the Porto Alegre Botanical Garden, State of Rio Grande do Sul, Southern Brazil and samples gathered later on from this same water body, a new species of Phacus (Euglenophyceae, Phacaceae), P. multifacies Alves-da-Silva & C. Bicudo, sp. nov., is here described and proposed as new to science. Cell displacement turning ventrally one full turn round itself and also rotating around its longitudinal axis and the presence of a dorsal wing-like expansion next to the caudal process are the main diagnostic features of the new species. Physical and chemical information on the pond water is presented.

Osteology of a New Specimen of Macrocnemus aff. M. fuyuanensis (Archosauromorpha, Protorosauria) from the Middle Triassic of Europe: Potential Implications for Species Recognition and Paleogeography of Tanystropheid Protorosaurs

Over the past two decades, a wealth of marine and terrestrial reptiles, including protorosaurian archosauromorphs, has been described from Triassic shales and limestone layers in southern China. Recovered from the eastern margin of the Tethys Ocean, these forms often show remarkable similarities to taxa that were previously known and described from Europe, i.e., the western Tethyan margin. One protorosaurian that is known from the western and the eastern Tethyan province is the genus Macrocnemus, with currently three recognized species: 1) M. bassanii from the Middle Triassic Besano Formation and Meride Limestone (late Anisian – early Ladinian), UNESCO World Heritage Site Monte San Giorgio, Ticino, Switzerland; 2) M. obristi from the Prosanto Formation (early Ladinian) of the Ducan area, Grisons, Switzerland; and 3) M. fuyuanensis from the Falang Formation (Ladinian), Yunnan Province, southern China. Recently a new specimen, PIMUZ T 1559, from the upper Besano Formation at Meride, Ticino, Switzerland, was prepared, revealing a disarticulated skeleton which includes most of the cranium and lower jaw, pre-caudal vertebral column and ribs, the forelimbs, and girdle elements. Unambiguously assignable to the genus Macrocnemus, it evinces particularly gracile elongated cervical ribs, as well as a humerus/radius ratio that is comparable only to that of M. fuyuanensis from southern China. Based on this feature we tentatively recognize the new specimen as M. aff. fuyuanensis from Europe. The position and exquisite preservation of the clavicle and interclavicle in this specimen allows a revision of the shoulder girdle of Macrocnemus when articulated, which also has implications for closely related protorosaurian taxa, such as the long-necked Tanystropheus. Furthermore, differences in the shape and morphology of the interclavicle including pointed wing-like lateral processes and a short, fusiform caudal process represent rare discrete characters that allow separation of the specimens of M. bassanii from the new specimen of M. aff. fuyuanensis.

Ultrastructural morphology and phylogeny of Henneguya gilbert n. sp. (Myxozoa) infecting the teleostean Cyphocharax gilbert (Characiformes: Curimatidae) from Brazil.

This paper describes light and ultrastructural observations and molecular analysis of a fish-infecting myxosporean, Henneguya gilbert n. sp., which was found infecting the gill epithelium of the commercially important freshwater teleost fish Cyphocharax gilbert (Curimatidae) collected in the estuarine region of Guandu River, Rio de Janeiro State, Brazil. The parasite occurs in the gills, forming whitish spherical to ellipsoidal polysporic cysts measuring up to ~750μm, and displaying asynchronous development. Mature myxospores are ellipsoidal with a bifurcated caudal process. The length, width and thickness of the body of the myxospore are 12.0×5.3×3.6μm, respectively; two equal caudal processes are 16.8μm long, and the total length of the myxospore is 27.2μm. There are two unequal polar capsules: the larger measures 5.5μm length×1.3μm width and has a polar filament with 9-10 coils; the smaller is 4.0μm long×1.3μm wide and has a polar filament with 7-8 coils. The sporoplasm is binucleated and presents a spherical vacuole surrounded by numerous globular sporoplasmosomes. Phylogenetic analysis, based on the small subunit rRNA sequencing, using maximum likelihood method reveals the parasite clustering together with other myxobolids that are histozoic and parasitize freshwater fish of the order Characiformes, thereby strengthening the contention that the host phylogenetic relationships and aquatic environment are the strongest evolutionary signals for myxosporeans of the family Myxobolidae.

Morphology and small subunit rDNA-based phylogeny of a new Henneguya species, infecting the ornamental fish Corydoras leucomelas from the Peruvian Amazon

A new species of Myxosporea, Henneguya loreotoensis n. sp. is described parasitizing the gill filaments from 17 of 35 specimens (48.5%) of Corydoras leucomelas (Siluriformes: Callichthyidae) caught in the Nanay River, near village Ninarumi, in the Loreto state, Peru. Mature spores were ellipsoidal in shape from the frontal view, measuring 36.2±0.1μm (36.1–36.3) in total length, 14.3±0.1μm (14.2–14.4) in body length, 5.1±0.1μm (4.9–5.3) in width and 21.9±0.1μm (21.8–22.0) in the caudal process. The two polar capsules were symmetrical and elongated, measuring 5.1±0.1μm (4.9–5.3) in length and 2.4±0.2μm (2.1–2.7) in width, containing a polar filament with five coils arranged obliquely to the longitudinal axis. The sporoplasm was binucleate. Partial sequencing of the ssu-rDNA of H. loretoensis n. sp. resulted in a total of 1676 nucleotides, and this sequence did not match any of the myxozoan available in the GenBank. The phylogenetic analysis shows H. loretoensis n. sp. as a sister species of Henneguya paraensis, another amazonian myxozoan parasite of Cichla temensis (Perciformes: Cichlidae).

Involvement of aurantiactinomyxon in the life cycle of Thelohanellus testudineus (Cnidaria: Myxosporea) from allogynogenetic gibel carp Carassius auratus gibelio, with morphological, ultrastructural, and molecular analysis

During the investigation of actinosporean fauna diversity from commercial fish ponds in Hubei Province, China, a novel aurantiactinomyxon type was found from Branchiura sowerbyi. Spore body of the aurantiactinomyxon was ellipsoidal in side view and triangular in apical view, 15.5±0.5 (14.5-16.4) μm in diameter; three leaf-like caudal processes were approximately equal, measuring 13.2±0.9 (11.5-16.2) μm long and 7.4±0.4 (6.7-8.0) μm wide at the base; three polar capsules were located at the apex of spore body, globular in apical view, 2.2±0.1 (2.0-2.3) μm in diameter, and pyriform in side view, 2.5±0.2 (2.3-2.9) μm in length and 2.0±0.2 (1.8-2.4) μm in width; a total of 32 germ cells were observed within the sporoplasm. Ultrastructural analysis showed that the development was asynchronous between pansporocysts but synchronous within a pansporocyst. The formation of sporoblast and the development of sporogonic stage were also described and discussed. The 18S ribosomal DNA sequences of the current aurantiactinomyxon type corresponded to that of a previously reported Thelohanellus testudineus, suggesting that the newly identified aurantiactinomyxon type is the actinosporean stage in the life cycle of T. testudineus.

Sakakibarana, a new genus of Gyponini (Hemiptera: Cicadellidae: Iassinae) from the Amazon Rainforest

A new genus of Gyponini, Sakakibarana gen. nov., is proposed and its type species S. amazonica sp. nov. is described and illustrated based on specimens from the Amazon Rainforest of Northern Brazil (states of Amazonas and Pará) and French Guiana. The new genus can be distinguished from other members of the Gyponini by the following morphological features: robust body, short crown, crown and face transition distinct and subfoliaceous, pronotum strongly declivous, male pygofer with caudal process, and aedeagus with dorsal apodemes with a pair of processes. A discussion comparing the new genus with the related genus Tenuacia DeLong, 1977 is provided.

Observations on non-random distribution of spores of Henneguya spp. (Cnidaria: Myxosporea: Myxobolidae) within plasmodia.

Species of the cnidarian genus Henneguya Thélohan, 1892 (Myxosporea: Myxobolidae) are histozoic parasites commonly found in freshwater and, more rarely, in marine fish. The development of these parasites in fish tissues includes the formation of plasmodia within which occurs the sporogony originating spores with two caudal processes, which are usually randomly distributed within the plasmodia. In this report the authors present some cases of non-random distribution of the spores of six species of Henneguya within their plasmodia. Two different patterns of non-random distribution were found based on a literature survey. These patterns and their origin are discussed. Apparently this non-random distribution of the spores is due to both internal and external factors.

New host record and molecular characterization of Dicauda atherinoidi Hoffman & Walker (Bivalvulida: Myxobolidae): a parasite of the emerald shiner Notropis atherinoides Rafinesque, 1818 and mimic shiner Notropis vollucellus Cope, 1865

Updated morphological and histopathological descriptions for Dicauda atherinoidi (Bivalvulida:Myxobolidae) and an expanded host range are supplemented with the first molecular data and phylogenetic analyses of the genus. Plasmodia were located on the head, ventrum/body and fins of infected emerald shiner Notropis atherinoides Rafinesque, 1818 and mimic shiner Notropis vollucellus Cope, 1865, a new host species. Myxospores were spherical, ranging 9.3-11.4μm (10.5±0.4) in length, 9.0-11.0μm (9.7±0.4) in width and 6.6-7.0μm (6.8±0.2) thick in sutural view, and possessed 2-3 caudal processes (5.3-68.3μm, 31.1±13.6) connected to the spore body at the sutural groove, all of which are consistent with the genus Dicauda. In the absence of available Dicauda sequence data, the 18S rDNA sequences from Michigan isolates were most similar to Myxobolus spp. Phylogenetic analyses clustered these isolates with myxobolid species from cyprinid fish, suggesting these parasites may represent an underpopulated group of cyprinid-infecting myxozoans. Histopathology revealed thin-walled plasmodial pseudocysts in the dermis and associated connective tissue, where granulomatous inflammation and focal scale atrophy were also present. Further sampling/sequencing of myxobolids from Notropis spp. should expand these underrepresented myxozoans and offer further insight into Myxobolidae host family tropisms.

Life history of Paraselenis (Spaethiechoma) dichroa (Germar, 1824) (Coleoptera: Chrysomelidae: Cassidinae) in natural conditions of Atlantic Forest from Brazil

ABSTRACTCassidinae Gyllenhaal​ is the second largest subfamily of Chrysomelidae (Coleoptera), which presents characteristic morphology, biology and behaviour. The current study describes the life cycle of Paraselenis(Spaetiechoma) dichroa (Germar), ​determining biological and behavioural aspects as well as the action of natural enemies on populations, when the species has maternal care. The study was conducted between February and April 2015 in the National Forest of Passa Quatro, municipality of Passa Quatro, Minas Gerais state, Brazil. Daily observations were made (morning and afternoon) to evaluate the offspring of females on Ipomoea sp. and Merremia macrocalyx (O’Donell​) (Convolvulaceae), as well as the actions of natural enemies on the young. The eggs are deposited on the midrib and abaxial surface of leaves (n = 25). Egg clusters are pedunculated, arranged in groups and devoid of any cover. On average, each female produced 27.3 ± 5.6 (n = 16) eggs, with a mean incubation period of 12.7 ± 2.9 days (n = 10 females with their young). The larvae remained grouped in the leaves throughout development, except when they fed. They retained faeces and exuviae as a stacked faecal structure on their mobile urogomphi (caudal process) like a faecal shield. The mean number of larvae per female was 12.7 ± 10.1 (n = 19) and the larval period lasted 24.9 ± 4.5 days (n = 12). Pupation occurred on the stem of the plant (n = 16). On average there were 8.1 ± 8.5 individuals for pupae progeny (n = 14). The mean duration of the pupal stage was 10.4 ± 3.3 days (n = 5). Overall, 3% of adults emerged (n = 13 individuals), with a total cycle time of 41.3 ± 8.4 days (n = 6). Adults are sexually dimorphic in the elytral shape. Females remain with the offspring throughout development. The natural enemies of immatures were Emersonella pubipennis Hansson​ (Hymenoptera: Eulophidae), Tachinidae (Diptera) and Stiretrus decastigmus (Herrich-Schaeffer​) (Heteroptera: Pentatomidae), Conura sp. Spinola​ (Hymenoptera: Chalcididae) and Brachymeria sp. Westwood​ (Hymenoptera: Chalcididae). The information presented here on the natural history of P. dichroa are important as they may serve as a starting point to understand evolutionary questions and multispecies interactions.

Description of a new Neoactinomyxum type actinosporean from the oligochaete Branchiura sowerbyi Beddard.

Actinosporean infection of oligochaetes living in the mud of a commercial gibel carp pond with myxosporean disease was studied. Six actinospore types were detected exclusively from the oligochaete Branchiura sowerbyi Beddard with very high prevalence (18%). Five out of the six types were identified as the same actinosporeans described in previous reports, the sixth actinosporean was identified as a new Neoactinomyxum type and described here based on morphological and molecular characterisation. Spore body of the actinospore was globular, much smaller than caudal processes. Three caudal processes were disc-like in apical view, hemispherical in side view, closer together and encircling the spore body. The number of sporoplasm cells was detected as eight in one specimen. The new actinosporean markedly differed from other Neoactinomyxum types in literature having much bigger caudal processes. DNA sequence analyses further confirmed the morphological identification, and revealed the actinosporean described here (KU641392) possessed less than 94% sequence similarity with myxozoans available in the GenBank database.

Henneguya laseeae n. sp. from flathead catfish (Pylodictis olivaris) in the upper Mississippi River.

A novel species of Henneguya was isolated from flathead catfish (Pylodictis olivaris) captured in the upper Mississippi River near Lansing (Allamakee County), IA, and La Crosse (La Crosse County), WI. Designated Henneguya laseeae n. sp., this novel species is described using critical morphological features, histology, and 18S ribosomal RNA gene sequence. Ovoid cysts, ranging from 1200 to 1800μm in width, tended to be at filament tips or in the distal third, often directly on the filament midline, but occasionally paramedian. Lanceolate-shaped myxospores were consistent with those of the genus Henneguya. The spore body was 16.2 ± 0.5μm (mean ± standard deviation; range = 15.1-17.0μm) in length, 6.0 ± 0.4μm (5.1-6.6μm) in width, and 4.7 ± 0.2μm (4.4-4.9μm) thick. The two polar capsules at the anterior of the spore body were 5.9 ± 0.3μm (5.3-6.3μm) in length and 1.8 ± 0.1μm (1.6-2.1μm) in width and contained six to seven turns in the polar filament. The caudal processes tapered to fine points and were 54.3 ± 2.9μm (49.1-61.7μm) in length. Total spore length was 70.4 ± 3.3μm (64.5-79.4μm). The spores and plasmodium of this species are of similar size and morphology to other species of Henneguya from ictalurid fishes. Additionally, the 18S rRNA gene sequences placed this isolate within a clade populated by Henneguya spp. from North American ictalurids. This is the first reported species of Henneguya from flathead catfish.

Redescription of Bythotrephes arcticus Lilljeborg, 1901 (Crustacea:Cladocera: Onychopoda) and confirmation of an independent species status of the distant Transcaucasian populations of the genus Bythotrephes Leydig.

Two species of the genus Bythotrephes Leydig, B. arcticus Lilljeborg and B. transcaucasicus Behning, forming a group of close species, are redescribed on the basis of type material and other materials from Northern Eurasia. They were investigated with the application of detailed morphological analysis, including intra- and interpopulation variability and the original scheme of morphometric measurements. The lectotypes and paralectotypes of the species were selected. B. arcticus compared with other species of the genus, seem more evolutionary primitive and less specialized, judging from its large body size, comparatively short tl I, short and straight caudal process, well developed distal setae on two proximal endopodital segments of tl I, and large number of claws. B. arcticus tends to occur in small and shallow water bodies, while B. transcaucasicus was predominantly found in pelagic zone of large and deep Transcaucasian lakes. B. arcticus is probably mainly distributed along the tundra and northern forest area of the Eurasian continent and the nearest islands from Scandinavia to Eastern Siberia. Its documented easternmost locality is situated near the northern part of the Yenisei River, whereas B. transcaucasicus was recorded in the second half of 19th-first half of 20th century in three closely situated mountain lakes in Turkey, Georgia, and Armenia. The presence of B. arcticus in Northern Kazakhstan and B. transcaucasicus in the distant Transcaucasia is linked with their (or their ancestor) hypothetical displacement to the south in the period of ice ages. More recent surveys of Transcaucasian lakes have not revealed the presence of B. transcaucasicus. The rare findings of this species in the past can imply that it could also be missed in the process of collecting but, on the other hand, it cannot be excluded that B. transcaucasicus become extinct as a result of an anthropogenic or other impact on Transcaucasian lakes.

Henneguya collaris sp. nov., (Myxosporidia), parasite of the Greenband Parrotfish Scarus collana Rüppell, 1835 (Actinopterygii, Scaridae) from the Red Sea, Egypt. A light and electron microscopic study.

The phylum Myxozoa comprises more than 2180 species, almost all of which are considered to be obligate parasites of aquatic fishes. In the present study, Henneguya collaris sp. nov. is the first described histozoic myxozoan species of the genus Henneguya infecting the kidney of the greenband parrotfish Scarus collana (Actinopterygii, Scaridae). One hundred and eighty specimens of fish were collected randomly during the period from September 2014 to October 2015 from boat landing sites and the market places at Hurghada City along the Red Sea in Egypt. Of these, 90 (50%) specimens were infected. Light microscopic examination showed that the infection was detected as mature spores with two polar capsules regularly arranged at the anterior pole of each spore and extruded polar filaments free in the kidney tissue. The spore body was oval in shape, measured 7.1 ± 0.2 (6.2-8.4) μm in length and 6.3 ± 0.2 (5.8-7.0) μm in width, with a bifurcated caudal process of equal length, reaching 6.3 ± 0.2 (5.8-7.0) μm in length. Polar capsules were 3.4 ± 0.2 (3.0-4.2) μm in length and 1.9 ± 0.2 (1.6-2.4) μm in width with 6-8 (10) turns of polar filaments. Ultrastructural analysis showed that the spore development was asynchronous. Sporogenesis, capsulogensis, valvogenesis, and spore maturation of the present parasite were also described. The present species was compared morphologically with the spore characteristics of the most similar species of Henneguya spp. recorded previously from different geographical areas taking into account the stage and dimensions of the spore body, tails, and polar filament coils, including their number and the most important characteristic features that distinguish them from the present species. Considering the data obtained, the material described herein represents a new species and the name Henneguya collaris sp. nov. is proposed.