Tail Research Articles

Hennegoides Africanus sp. nov. from Kadey River in Cameroon.

Fish are susceptible to various parasitic infections, with Myxozoa emerging as a major group. A taxonomic study of Myxozoa is essential for the rapid diagnosis of species potentially responsible for epizootic diseases. The studied fish was collected from the Kadey River, a tributary of the Sangha River in the Congo Basin in Cameroon, and parasitologically dissected. Cysts from gill samples were examined morphologically and molecularly to assess myxozoan diversity and phylogenetic relationships were determined based on SSU rDNA. Infection by Hennegoides africanus sp. nov., found in gill filaments of 60% of C. gibbosus. Infection characterized as intrafilamental-epithelial type. Myxospore body vaulted on one side, measured 13.5 (12.4-14.8) × 2.1 (1.9-2.5) µm. Caudal appendages measured 31.3 (25.4-34.93) µm, made of thick and filamentous segments. Two polar capsules elongated, differing in size and position; smaller capsule near anterior end measured 2.8 (2.18-3.54) × 0.9 (0.7-1.1) µm, while larger, located posteriorly, measured 3.8 (3.21-4.45) × 1.4 (1.2-1.7) µm. The SSU rDNA gene sequence of Hennegoides africanus sp. nov. does not match any sequences in GenBank and is closely associated with two undetermined species of Henneguya and Myxobolus infecting the gills of Characiformes in Africa. Morpho-molecular evidence indicates that Hennegoides africanus sp. nov. is a new species to science and the first reported member of its genus in Africa.

The big, the small and the weird: A phylogenomic analysis of extant Priapulida.

Priapulida is a small phylum of 22 described species that are divided into two size classes (microscopic and macroscopic), distinguished by adult and larval morphology. Most priapulidans are rare or live in inaccessible habitats, and freshly collected material for molecular studies is difficult to obtain. With this study, we for the first time aim to resolve the phylogeny of extant Priapulida using transcriptomic, genomic, and morphological data. We analyze six newly assembled transcriptomes alongside existing data, covering seven species and four genera. Additionally, we include genomic data from museum-preserved species, adding another genus via low-coverage genome sequencing. Conserved regions from these data produce a combined phylogenomic tree, augmented by morphological data to suggest positions for the rare taxa Acanthopriapulus and Maccabeus. Our findings show that the microscopic Meiopriapulus consistently groups as a sister taxon to other priapulidans and not with Tubiluchus, as suggested in previous studies. Maccabeus, which exhibits both size-class characteristics, is the sister taxon to all the macroscopic species, while Acanthopriapulus is a sister taxon to Priapulus, but molecular data are needed to support their suggested positions. Ancestral state reconstruction suggests that small body size, lack of caudal appendages, and internal fertilization are ancestral traits for Priapulida. This supports the derived evolution of macroscopic size and other traits in the group, aligning with its microscopic sister groups Kinorhyncha and Loricifera. Due to the diversity of priapulidans and the unique morphologies of some species, further fossil studies and potential discoveries of priapulidan microfossils are essential to fully understand the evolutionary history of this phylum.

Teratological abnormalities in hard ticks (Acari: Ixodidae) from Pakistan.

Studying teratological abnormalities in ticks are taxonomically important because this poorly understood biological phenomenon causes difficulties in tick's identification. Globally, reports regarding these abnormalities in ticks, reasons of their causes and their impacts are scarce. According to the available published data, there are no studies regarding teratological abnormalities in ticks from Pakistan. Herein, ticks examined for these abnormalities were museum deposited, collected from buffalos, cattle, camels, goats and sheep in 17 districts of Pakistan during 2017-2023. The abnormalities were observed in 88 out of 3279 (2.68%) ticks, representing eight ixodid species (Rhipicephalus microplus, Rhipicephalus turanicus, Rhipicephalus haemaphysaloides, Haemaphysalis bispinosa, Haemaphysalis montgomeryi, Hyalomma anatolicum, Hyalomma scupense, Hyalomma dromedarii). Among abnormal ticks, 67 abnormalities were characterized as local, 12 as general and nine as a combination of both. Local abnormalities were observed in the scutum, palpal segments, anal aperture, spiracular plates, ventral plates, caudal appendage, festoons and posterior grooves. Also, the constrictions and excavations of body parts were observed. General abnormalities included irregular idiosoma and lateral idiosomal bifurcation. This study, for the first time, highlights the diversity of teratological abnormalities in Pakistani ticks, and are reported in in Hy. anatolicum, Ha. bispinosa and Ha. montgomeryi for the first time.

Morphological and molecular characterization of Henneguya cardii n. sp. (Cnidaria: Myxosporea) from the bulbus arteriosus of European seabass Dicentrarchus labrax (Teleostei: Moronidae).

A new species of Myxobolidae, Henneguya cardii n. sp., is described infecting the European seabass Dicentrarchus labrax, a fish of high commercial value intensively cultivated in southern Europe. Henneguya cardii n. sp. was found in the bulbus arteriosus and spleen with a prevalence of infection of 13.5%. In the heart, it forms irregular whitish plasmodia measuring 1 mm in size. Mature myxospores are broadly obovoid in frontal view and ellipsoidal in lateral view, with 2 equal caudal appendages. Polar capsules are ovoid and symmetric, with 3–4 polar tubule coils. Myxospores measure 10.2 ± 0.6 (8.8–11.6) μm in length, 8.0 ± 0.7 (5.3–8.8) μm in width and 5.6 ± 0.2 (5.1–6.4) μm in thickness. Caudal appendages are 36.6 ± 3.2 (27.4–42.9) μm long. Total spore length is 47.6 ± 3.2 (41.2–53.2) μm. Polar capsules measure 4.0 ± 0.2 (3.4–4.6) by 2.2 ± 0.1 (1.9–2.6) μm. Small subunit ribosomal RNA-based tree topologies position H. cardii n. sp. within a lineage of marine myxobolids that is mostly comprised of other Henneguya species. Host-relatedness is reinforced as the main evolutionary driver for myxobolids, with the positioning of H. cardii n. sp. further suggesting tissue tropism as another important evolutionary driver for marine heart infecting Henneguya. Nonetheless, the inner complexity of this lineage suggests that identification of the evolutionary patterns driving its phylogeny will require discovery of the true diversity of marine myxobolids.

Myxobolus liuyangensis sp. n. (Myxosporea: Myxobolidae) from the gills of exotic mrigal carp Cirrhinus mrigala (Actinopterygii: Cyprinidae) in China.

A new species, Myxobolus liuyangensis sp. n., was found in the gills of the exotic mrigal carp Cirrhinus mrigala during a survey of the fauna of exotic fish myxospore in China. Plasmodia were elongated pyriform, measuring 0.42 mm long and 0.15 mm wide. The mature spores were elongated pyriform in the frontal view, tapered forward, rounded posterior end, and fusiform in the sutural view, measuring 17.3 ±0.5 (16.5-18.3) μm long, 6.2 ±0.3 (5.2-6.8) μm wide, and 4.8 ±0.2 (4.4-5.1) μm thick. The two equal polar capsules of elongated pyriform in shape measured 11.3 ±0.5 (10.6-12.3) μm long and 2.5 ±0.3 (2.0-3.1) μm wide, occupying more than half the capacity of the spores. The polar filaments were coiled with fifteen to sixteen turns. No mucous envelope and caudal appendages were found. The consensus SSU rDNA gene sequence obtained here for M. liuyangensis sp. n. did not match any sequences available in GenBank, but was most closely related to M. catlae that infects the gills of C. cirrhosis (MT003664, 97.99% similarity). Phylogenetic analysis indicated that the C. mrigala-infecting Myxobolus species were not clustered together, but dispersed in different clades. The present species clustered with M. catlae and M. orissae within the clade I of elongated pyriform spore shapes, revealing spore shapes may play an important role during the evolution of Myxobolus species. This is the second myxosporean infection report in the exotic mrigal carp C. mrigala.

Devadatta adii sp. nov. (Odonata: Zygoptera: Devadattidae) from Upper Siang District, Arunachal Pradesh, India.

We erect a new species Devadatta adii sp. nov. based on five males and five females collected from Upper Siang District, Arunachal Pradesh, India. The males of the new taxon are unique in terms of having a golden yellow lateral pterothorax, strongly curved cerci and filamentous genital ligula. We also provide illustrations of male thorax and caudal appendages of Devadatta spp..

Human Tails and Whole Exome Sequencing Findings: Is There any Association? A Case Report

Introduction: The human tail is a rare congenital condition characterized by a caudal cutaneous appendage, primarily located in the lumbosacral region. These tails are often associated with other congenital malformations, most notably spinal dysraphism. Case Presentation: A 3-week-old male neonate was referred to the Baqiyatallah Pediatric Clinic in Tehran, Iran, due to a 12-cm-long congenital tail-like appendage in his lumbosacral region, which contained only soft tissue upon palpation. There was no apparent neurological deficit on physical examination or magnetic resonance imaging. No other concomitant malformations were present. The parents were consanguineous, and a previous pregnancy had been terminated at 18 weeks of gestation due to a prenatal diagnosis of a neural tube defect. As a result, genetic consultation and whole exome sequencing were performed. Some phenotype-related variants of uncertain significance were detected, and the baby was also found to be heterozygous for oculocutaneous albinism. Conclusions: Although some genetic variants of uncertain significance and a pathogenic variant associated with albinism were identified in this case, the absence of other manifestations beyond the tail and the lack of literature on this topic make the clinical implications of genetic testing in human tails unclear. Further investigation is required to understand these implications.

New morphological structures of Priapulus caudatus, Lamarck 1816 (Priapulida) and analysis of homologous characters across macroscopic priapulids

The macroscopic Priapulus caudatus Lamarck, 1816 is one of the most investigated priapulids, yet, the adult morphology warrants detailed characterization and analyses of potential priapulid homologies. Using light microscopy, scanning electron microscopy and histology, we examine adult specimens of P. caudatus from three localities in the Northeast Atlantic and the Arctic Oceans (Gullmarsfjord, North Sea, White Sea). Our examinations show ring papillae on the posterior trunk of P. caudatus for the first time in detail and describe previously overlooked structures on the circumoral field (hemispherical papillae, ring 0 scalids and circular folds). In addition, we add new information on pharyngeal teeth, scalids, trunk papillae, posterior warts, and on spinulets of the caudal appendage. The new collected data of P. caudatus allows us to compare structures across species of the macroscopic Priapulidae (Acanthopriapulus, Priapulopsis, Priapulus, Halicryptus) in detail and to build hypotheses on their homology within this clade.

Description of Protosticta khasia sp. nov. and Yunnanosticta siangi sp. nov., with new records of P. samtsensis Gurung & Phan, 2023 from Northeast India (Odonata: Zygoptera: Platystictidae).

Protosticta Selys is a genus of damselflies of the family Platystictidae Kennedy found in forests of tropical Southeast Asia. The genus Protosticta has rarely been reported from Northeast India. In this paper, we describe Protosticta khasia sp. nov. (subfamily Protostictinae Dijkstra et al.) based on holotype male and paratype female collected from Maraikaphon, East Khasi Hills district, Meghalaya, India. Protosticta khasia can be identified by the markings of the prothorax and the shape of the male paraproct with two arms. We also describe Yunnanosticta siangi sp. nov. (subfamily Sinostictinae Wilson) from Arunachal Pradesh, India, based on two males and two females. This species is differentiated from its congeners by the thoracic and abdominal markings as well as the shape of male caudal appendages. The key for males of Yunnanosticta is provided. Additionally, we provide new records of Protosticta samtsensis Gurung & Phan, along with an updated key to the Protosticta species of Northeast India.

Macromia kannharaiensis, a new species of dragonfly (Insecta: Odonata: Macromiidae) from Maharashtra, India.

We describe a new species of dragonfly Macromia kannharaiensis sp. nov., based on a male and a female specimens collected from Dodamarg taluka, Sindhudurg district, Maharashtra. The new species belongs to the calliope-group (species group initially discussed by Laidlaw 1922), and it can be distinguished by its congeners on the bases of specific colour pattern on postclypeus, markings on S2 and S8, shape and structure of caudal appendages and accessory genitalia.

Henneguya (Cnidaria: Myxobolidae) species infecting Oligosarcus jenynsii (Characiformes: Characidae) in a Neotropical shallow lake from Argentina: morphological and molecular characterisation.

Two previously undescribed myxozoan species, Henneguya sardellae sp. n. and H. margaritae sp. n., found infecting connective tissues of the Neotropical characid fish Oligosarcus jenynsii (Günther) from Argentina are morphologically and molecularly characterised. Mature spores of H. sardellae sp. n. are ellipsoid, with two, straight and visibly fused caudal appendages cleaved at its blunt terminal end; measuring 33.5 ± 1.2 (30.9-35.5) μm in total length, spore body 17.5 ± 0.6 (16.3-18.6) µm, 7.8 ± 0.4 (7.0-8.8) µm wide and 6.9 ± 0.2 (6.6-7.2) µm thick, with two elongated, unequally-sized polar capsules situated at anterior end, and 11-13 turns of polar tubules. Mature spores of H. margaritae sp. n. are pyriform, with two caudal appendages visible fused together and much longer than spore body, with unequal endings; measuring 35.9 ± 2.8 (29.2-40.7) µm in total length, spore body 11.5 ± 0.9 (9.2-13.0) µm long, 5.8 ± 0.4 (5.1-6.7) µm wide and 5.5 ± 0.2 (5.1-5.8) µm thick, with two polar capsules similar in size, pyriform polar capsules containing polar tubules with 4-5 coils. Both species showed a membraneous sheath surrounding the spore body and caudal appendages; in H. sardellae sp. n. this feature can deploy laterally. Phylogenetic analyses based on SSU rDNA sequences showed that H. sardellae sp. n. and H. margaritae sp. n. clustered with other myxobolids parasitising Characiformes in Brazil, Cichliformes in Mexico and Cyprinodontiformes in Mexico and the United States. The description of these two new species of Henneguya as the first described species of the genus that parasitise freshwater fish in Argentina highlights the importance of further research on the diversity and distribution of myxozoans in this region.

150th anniversary of Alberto Santos-Dumont’s birth, the father of aviation: the damselfly Cyanallagma demoiselle sp. nov. from the Brazilian Atlantic Forest (Odonata: Coenagrionidae)

Cyanallagma demoiselle sp. nov. (holotype male deposited in DZUP: Brazil, São Paulo State, Cananéia, Ilha do Cardoso State Park), a new small greenish blue and black damselfly, is described, illustrated, and diagnosed based on males and females from the southeastern Atlantic Forest. This new coenagrionid is named after one of the most celebrated projects, the Demoiselle 20 or libellule aircraft, designed by the Brazilian inventor and aviation pioneer Alberto Santos-Dumont (1873–1932). This is the third new odonate species discovered in the same restinga-like formation at São Paulo, and like many other odonates from this assemblage, C. demoiselle sp. nov., appears to be a typical inhabitant of this type of environment. Due to its sharing many characteristics with other Cyan­allagma, the new species can be considered a chimera. Its body coloration and genital ligula are similar to those of C. trimaculatum, whereas its caudal appendages closely resemble those of C. nigrinuchale. Despite of recent advances in taxonomic knowledge about Cyan­allagma, this study highlights the need for better understanding the morphological correspondences or homologies among the structures of caudal appendages.

Adaptive tails? Parallel evolution of expanded tails in monsoonal tropics lineages of an Australian gecko radiation (Oedura)

Abstract Ecological drivers of variation in the morphology of the lizard tail are understudied despite its important and varied functions in defence, locomotion, balance, climbing, and resource storage. We quantified variation in original tail shape and surface area-to-volume ratio (SA : V) in an Australian gecko clade (Oedura) and tested whether environmental variables are predictors of this variation. To use museum specimens, we developed an approach to straighten deformed preserved tails for accurate shape analysis. Tail shape varied from a relatively ‘typical lizard’ tail—long, tapered, and circular in cross-section—to a distinctive expanded, wide, and flat shape. Extreme versions of the latter shape seem to have evolved in parallel in two distantly related lineages. Wide tails and low SA : V ratio values occur in the Australian Monsoonal Tropics, while arid zone species all had a narrow, tapered tail with high SA : V. These data suggest expanded or bulbous tails may be analogous to succulence in plants and an adaptation for resource storage in environments with predictable peaks (wet season) and dearths (dry season) of resource availability. However, limited replicated evolution of bulbous tails precludes statistical significance in this case, and more analyses of tail anatomy in Oedura and other lizard clades are required to test this hypothesis further.

Myxobolus dumerilii sp. n. (Myxozoa: Myxobolidae) infecting the brain of Chinese longsnout catfish Tachysurus dumerili (Bleeker) in China.

During an investigation of Myxobolus diversity in the Chinese longsnout catfish Tachysurus dumerili (Bleeker), a new species infecting the intracranial epidermis of the host was discovered. Upon opening the cranial cavity, several round whitish plasmodia measuring 0.55-0.80 mm in diameter were observed. Fresh spores (n= 50) were pyriform in the frontal view and fusiform in the sutural view, with a length of 15.4±0.6 (13.9-16.5) μm, width of 9.1±0.4 (8.3-9.8) μm, and thickness of 7.0±0.4 (6.3-7.9) μm. The spores had smooth shell surfaces and transparent membrane sheaths in the posterior. No folds, intercapsular appendix, and caudal appendages were observed. Two equal polar capsules were pyriform and measured 7.5±0.5 (6.7-8.7) μm in length and 3.2±0.3 (2.5-3.6) μm in width. The polar filaments were coiled with five to six turns and perpendicular to the polar capsule length. A BLAST search indicated M. dumerilii sp. n. was closely related to five Myxobolus species (with sequences similarities ranging from 90.54% to 96.52%) found in different organs of yellow catfish Tachysurus fulvidraco (Richardson), rather than the T. dumerili-infecting species M. branchiola Dong and Zhao, 2014 (with 90.5% sequence similarity). Phylogenetic analysis showed that M. dumerilii sp. n. didn't form sister clade with brain-infecting Myxobolus spp, but clustered with M. jianlinensis Gao et Zhao, 2020 and M. voremkhai Akhmerov, 1960 within the Siluriformes-clade with highly supported values, indicating that the host specificity may play a stronger signal than site infections during the evolution of Myxobolus species. Based on the morphological, ecological, and molecular differences observed between the newly discovered species and other available Myxobolus species, M. dumerilii sp. n., is proposed and described in this study.

Morphological, histopathological, ultrastructural and phylogenetic analysis of Henneguya archosargus n. sp. (Cnidaria, Myxosporea) infecting the sparid fish Archosargus probatocephalus in Brazilian waters

The introduction of new fish species to the aquaculture industry is essential to halt the progressive decline of natural fish stocks. The sheepshead Archosargus probatocephalus is a commercially valuable sparid fish with potential for breeding in captivity, but with limited information regarding parasitic infections that could pose a significant threat for its sustainable production. Thus, the present study aimed to study the myxozoan diversity infecting A. probatocephalus. A novel Henneguya sp. was detected forming plasmodia in the gill lamellae of specimens inhabiting the Brazilian coast, and is characterized based on morphological, histopathological, ultrastructural, molecular, and phylogenetic data. Myxospore total length was 21.3 ± 0.8 μm, with myxospore body 10.0 ± 0.5 μm long, 6.2 ± 0.3 μm wide, and 4.8 ± 0.5 μm thick. Caudal appendages were 10.3 ± 0.5 μm long and did not present any type of coating. Two pyriform polar capsules, 3.4 ± 0.3 μm long and 1.5 ± 0.2 μm wide, each containing an isofilar polar tubule with 4–5 coils. Histopathological analyses showed large intralamellar polysporic plasmodia associated with vascular congestion of the gill filament and gill lamellae, as well as epithelial hyperplasia causing partial or total fusion of gill lamellae. Maximum likelihood and Baysesian inference SSU rDNA-based phylogenetic analyses showed the novel sequence grouped within the marine clade of Henneguya spp. that mostly parasitize fishes belonging to Eupercaria incertae sedis.

Description of Protosticta armageddonia sp. nov. (Odonata: Zygoptera: Platystictidae) from the Western Ghats of India

A new species of Protosticta Selys, 1885 is described based on specimens collected from Kerala, northeast of Thiruvananthapuram, in the southern parts of the southern Western Ghats of India. Protosticta armageddonia sp. nov. is compared with all other known Protosticta species of the Western Ghats to provide comprehensive differential diagnosis. The new species is distinguished from its congeners by a combination of characters, including a marking on the ventral side of thorax, structure and colour of the prothorax, markings on the 8th abdominal segment, and the structure of caudal appendages and genital ligula. Furthermore, we provide preliminary information on the ecology and natural history of the new species.

First report of a histozoic Henneguya (Cnidaria, Endocnidozoa) infecting a synbranchid potamodromous fish from South America: Morphostructural and biological data

In this study, a Henneguya myxosporean species is described to infect an ecological, biological, and evolutionary important fish from Amazon biome. The myxosporean was found in the skin of only one specimen of marbled swamp eel, Synbranchus marmoratus caught in a small stream from Peruvian Amazon floodplain. Mature myxospores have ovoid shape from the valvular view, measuring 32.2 ± 0.6 μm (31.6–32.8) in total length, 21.5 ± 0.3 μm (21.2–21.8) in spore body length, 11.7 ± 0.5 μm (11.2–12.2) in width and 10.6 ± 0.9 μm (9.7–11.5) in thickness. Non-bifurcate caudal appendage, measuring 10.7 ± 0.4 μm (10.3–11.1) in length. Two polar capsules elongated aubergine in shape, equal in size and measuring 4.9 ± 0.2 μm (4.7–5.1) in length and 3.1 ± 0.5 μm (2.6–3.6) in width. Polar tubules coiled in 7–8 turns. This is the first report of a Henneguya species parasitizing a fish of the order Synbranchiformes from Amazon basin and the first to describe this parasite infecting a potamodromous fish from South America.

Excellent Improvement of Contact Resistivity and Thermal Stability for High Temperature Process After Silicidation of TiSi2 Through Ta Interlayer for Diffusion Barrier

Titanium Silicide (TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) is a primary contact material with low-resistance contact characteristics used in nanodevices. However, the rapid scaling trend requires further improvement to achieve both high thermal stability and low contact resistivity. Herein, a method for simultaneously improving the contact resistivity and thermal stability of the TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si interface is proposed by inserting a Ta interlayer into Ti/p-Si. The Ta-interlayered TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (Ta IL TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) achieves an improved contact resistivity by approximately 7.9 times compared to that without the Ta interlayer. This remarkable improvement is due to the smooth contact morphology resulting from the suppressed excess diffusion of Ti and Si and dopant segregation at the TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si interface. Particularly, because additional reaction during post annealing is minimized by the Ta interlayer, Ta IL TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> shows a low sheet resistance of 3.71 Ω/□ even after post annealing at 600 °C & 30 min, which is much lower than the conventional TiSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> scheme under the same annealing conditions. These results are expected to provide insights into state-of-the-art CMOS-based devices that require both low contact resistivity and better thermal margins.

Identification and characterization of Myxobilatus channi n. sp. (Cnidaria: Myxosporea) infecting the alimentary tract of northern snakehead Channa argus cultivated in China

The northern snakehead Channa argus is a freshwater fish of high economic importance in Asian countries. Intensive snakehead cultivation requires the regular addition of feedwater to ensure water quality, providing an opportunity for parasite transmission. However, the parasite composition of northern snakehead is still poorly studied. In a series of investigations conducted in China, a myxosporean species was isolated from the farmed northern snakehead. It manifested with a dense formation of ellipsoidal, proliferous cysts presenting along the wall of the intestine and pyloric caeca. The microorganism inside the cyst displayed elongate, pyriform, and bivalved myxospores, with an elongated caudal appendage extending from posterior extremity of each smooth shell valve. Two pyriform polar capsules were situated at a level perpendicular to the sutural plane. Based on these observations, the present isolates was assigned to the genus Myxobilatus. However, it was morphologically distinguishable from other congeners. Moreover, the same result was obtained according to a less than 92% top genetic identity observed in pairwise comparison. Therefore, we confirmed the present species new to science and designated it as Myxobilatus channi n. sp. Histologically, plasmodia bulging toward the mucosa were confined to the circular muscle layer, leading to epithelial sloughing and necrosis of the intestinal villi. Phylogenetically, M. channi n. sp. was positioned branching from those species belonging to the family Myxobilatidae, implicating the inability of morphological taxonomy to reflect the true evolutionary relationship among myxosporeans. This study enhances the understanding of the composition of the parasite infecting the northern snakehead that will inform future scrutiny and management of the parasite infection.

Henneguya correai n. sp. (Cnidaria, Myxozoa) Parasitizing the Fins of the Amazonian Fish Semaprochilodus insignis

We used a combination of morphological, molecular and biological data to characterize a novel Henneguya (Myxozoa) species infecting the Amazonian prochilodontid Semaprochilodus insignis or “kissing prochilodus”, a popular food fish and aquarium species in the Brazilian Amazon. Twenty-one S. insignis were caught live from the Tapajós river, Pará State, Brazil, then examined for myxozoan infections. Cysts of a novel Henneguya species were observed in the connective tissue of the fins. Myxospores measured 48 ± 4.9 (39.5–60.8) µm total length, of which caudal appendages were 33 ± 4.5 (26.4–45.2) µm and spore body was 15 ± 1.6 (12.4–20.5) µm. The spore body was 4.0 ± 0.6 (2.7–5.3) µm wide × 3.2 ± 0.4 (2.7–3.6) µm thick, with two unequal polar capsules (nematocysts) 7.2 ±0.8 (5.2–8.3) × 1.5 ± 0.3 (1.0–2.2) µm for the larger capsule and 5 ± 0.7 (4.0–6.3) × 1.4 ± 0.2 (1.0–1.8) µm for the smaller capsule. Polar tubules had 8–13 turns. Generative cells, immature and mature myxospores were observed within plasmodia. Ultrastructure showed plasmodia surrounded by collagen fibers, with the plasmodial membrane having pinocytotic channels. Phylogenetic analysis of small subunit ribosomal DNA sequences showed that the new Henneguya species clustered as a sister taxon to Henneguya tietensis, a parasite of the gills of the prochilodontid fish Prochilodus lineatus, from the geographically distant Paraná–Paraguai River basin.