Evaluating energy dispersive X-ray analysis (EDXA) as a diagnostic tool in acanthocephalan taxonomy as evidenced in Palaeacanthocephala and Archiacanthocephala.

We have examined the anterior and middle hooks of many specimens of 3 species of acanthocephalans from Ukraine including (1) adults of Acanthocephalus ranae (Schrank, 1788) Lühe, 1911 from 4 species of frogs in 6 geographical locations, (2) adults of Southwellina hispida Van Cleave, (1925) Witenberg, 1932 from 3 species of birds in 2 geographical locations, and (3) adults and cystacanths of Sphaerirostris picae (Rudolphi, 1819) Golvan, 1956 from 1 species of birds, 1 species of lizards, and 1 species of mammals in 2 geographical locations, to analyze their Ca, S, and P spectra using Energy dispersive x_ray analysis (EDXA), and account for their intraspecific variabilities. Adults of each of A. ranae from frogs and adults of S. hispida from birds each showed comparable metal spectra irrespective of host species and geography, especially when metal weight percent figures are averaged. In S. picae, 5 adult specimens from birds had comparable spectra but the cystacanth from hedgehog, a mammal, had particularly dissimilar pattern with much lower levels of P and Ca. We have also studied the EDXA patterns in anterior, middle and posterior hooks of cystacanths, juveniles, and adults of Moniliformis kalahariensis Meyer, 1931 much lower levels of P and Ca. in South Africa, Botswana, and India collected from their invertebrate intermediate and vertebrate definitive hosts to examine the EDXA profiles. Our conclusions were comparable to those reached from the Ukrainian material with the additional emphasis on the importance of using the same developmental stage in comparing interspecific EDXA profiles. The importance of the stability of the levels of S in various developmental stages across the host species barrier is exemplified by its relationship to the genetically based protein synthesis, which gives credibility to the usage of EDXA for diagnostic purposes. Our findings show that EDXA is a useful tool to characterize the taxonomic identity of species of Acanthocephala providing that (1) a population of a number of individual specimens are analyzed and average weight percent figures of metals are used for comparisons, and (2) comparisons are made using specimens of the same developmental stage and from hosts of the same class of vertebrate. When these conditions are met, the metal spectra for each species will prove valid for diagnostic purposes.

A comparative assessment of the morphology of Profilicollis altmani (Acanthocephala, Polymorphidae) from crustaceans and shore birds in Peru, with special notes on hook elemental analysis (EDXA), SEM imaging, histopathology, and molecular profile.

The morphology of cystacanths and adults of Profilicollis altmani (Perry, 1942) Van Cleave, 1947 (Polymorphidae) were studied from the Pacific mole crab Emerita analoga (Stimpson) (Crustacea, Hippidae) and Belcher's gull Larus belcheri (Vigors) (Aves, Laridae), respectively, in Peru. Comparative morphometrics with accounts of other populations of P. altmani from elsewhere off the Pacific and Atlantic coasts of North and South America revealed marked intraspecific population variations. We report scanning electron micrographs (SEM) of new features, not before noted or captured in line drawings by earlier observers. We further present microscope images that reveal internal details not previously reported or possible to see with SEM. Energy dispersive X-ray analysis (EDXA) revealed unusual patterns in the chemistry of proboscis hooks especially the high sulfur and diminished phosphorous and calcium in hook tips and low sulfur and high levels of phosphorous and calcium at mid hooks. The size and shape of all hooks of the cystacanths are reported for the first time. Histopathological studies in L. belcheri from Peru are also included. Cystacanths of P. altmani from California were also analyzed for molecular patterns and compared with other sequences reported from other locations. The molecular data and the analysis of our new sequences of cytochrome oxidase I (COI) showed that haplotypes of P. altmani had low genetic variation; the species is not geographically structured, and within its clade no monophyletic group is formed.

TITLE: Évaluation comparative de la morphologie de Profilicollis altmani (Acanthocephala, Polymorphidae) de crustacés et d'oiseaux de rivage au Pérou, en particulier l'analyse élémentaire des crochet (EDXA), l'imagerie SEM, l'histopathologie et le profil moléculaire. ABSTRACT: La morphologie des cystacanthes et des adultes de Profilicollis altmani (Perry, 1942) Van Cleave, 1947 (Polymorphidae) a été étudiée, respectivement, à partir du crustacé Emerita analoga (Stimpson) (Crustacea, Hippidae) et du Goéland Siméon Larus belcheri (Vigors) (Aves, Laridae), au Pérou. La morphométrie comparative avec des données d'autres populations de P. altmani d'autres localités au large des côtes du Pacifique et de l'Atlantique de l'Amérique du Nord et du Sud a révélé des variations intraspécifiques marquées des populations. Nous rapportons des nouvelles observations de microscopie électronique à balayage, non notées auparavant ou non capturées dans des dessins au trait par des observateurs antérieurs. Nous présentons en outre des images au microscope qui révèlent des détails internes qui n'ont pas été signalés auparavant ni possibles à voir avec MET. L'analyse aux rayons X à dispersion d'énergie (EDXA) a révélé des modèles inhabituels dans la chimie des crochets de la trompe, en particulier la teneur élevée en soufre et une diminution du phosphore et du calcium dans les pointes des crochets et des niveaux faibles en soufre et en phosphore et en calcium au milieu des crochets. La taille et la forme de tous les crochets des cystacanthes sont décrites pour la première fois. Des études histopathologiques sur L. belcheri du Pérou sont également incluses. Les cystacanthes de P. altmani de Californie ont également été analysés pour les modèles moléculaires et comparés à d'autres séquences rapportées d'autres endroits. Les données moléculaires et l'analyse de nos nouvelles séquences de cytochrome oxydase I (COI) ont montré que les haplotypes de P. altmani avaient une faible variation génétique. L'espèce n'est pas structurée géographiquement, et au sein de son clade aucun groupe monophylétique n'est formé.

Phylogeny and Life Cycles of the Archiacanthocephala with a Note on the Validity of Mediorhynchus gallinarum.

PURPOSE: The molecular profile of specimens of Mediorhynchus gallinarum (Bhalero, 1937) collected from chickens, Gallus gallus L. in Indonesia was analysed. The aim of this study was to assess the phylogenetic position of species of Mediorhynchus within the order Giganthorhynchida. METHODS: We used one mitochondrial gene (cytochrome oxidase 1) and one nuclear gene (18S ribosomal RNA) to infer phylogenetic relationships of class Archiacanthocephala. RESULTS: The COI and 18S rDNA genes sequences showed that M. gallinarum had low genetic variation and that this species is sister to Mediorhynchus africanus Amin, Evans, Heckmann, El-Naggar, 2013. The phylogenetic relationships of the Class Archiacanthocephala showed that it is not resolved but, however, were mostly congruent using both genes. A review of host-parasite life cycles and geographic distributions of Archiacanthocephala indicates that mainly small mammals and birds are definitive hosts, while termites, cockroaches, and millipedes are intermediate hosts. CONCLUSIONS: While the intermediate hosts have wide geographic distributions, the narrow distribution of the definitive hosts limit the access of archiacanthocephalans to a wider range of prospective hosts. Additional analyses, to increase taxonomic and character sampling will improve the development of a robust phylogeny and provide more stable classification. The results presented here contribute to better understanding of the ecological and evolutionary relationships that allow the host-parasite co-existence within the class Archiacanthocephala.

Redescription and Molecular Characterization of Pachysentis canicola Meyer, 1931 (Acanthocephala: Oligacanthorhynchidae) from the Maned Wolf, Chrysocyon brachyurus (Illiger, 1815) in Texas.

BACKGROUND: The original description of Pachysentis canicola Meyer, 1931 was based on an unknown number of specimens from an undetermined species of Canis in Brazil from the Berlin Museum. It has since been reported from other carnivores in South and North America. Our specimens from the maned wolf, Chrysocyon brachyurus (Illiger, 1815), in Texas, represent a new host record, and has shed more light on morphometric characteristics missing from the original description, and expanded the range of variations in characters that remained fixed since 1931 and that have been repeated in other taxonomic accounts. We have found additional specimens in striped skunk, Mephitis mephitis Schreber, also in Texas. METHODS: We have performed metal analysis on hooks using EDXA (energy dispersive X-ray analysis). Sequences for the 18S gene and ITS1-5.8-ITS2 region of rDNA were generated to molecularly characterize the species for the first time. RESULTS: Worms with a massive trunk and a globular proboscis with prominent dome-like apical organ and 12 irregular spiral rows of 4-5 hooks deeply embedded in cuticular folds each, totaling 48-60 hooks. We have included line drawings of the male and female reproductive systems, among other structures, also missing from the original and subsequent descriptions. We describe a new population of P. canicola from Texas and report on the metal analysis of its hooks using EDXA. We also assess the phylogenetic position of P. canicola supporting its independent status in the family Oligacanthorhynchidae, inferred from the two molecular markers. CONCLUSIONS: This is the foremost molecular characterization of any species of Pachysentis and will provide significant insights and reference for future molecular study of species of Pachysentis, especially from this newly described Texas population.

New morphological and molecular perspectives about Macracanthorhynchus hirudinaceus (Acanthocephala: Oligacanthorhynchidae) from wild boar, Sus scrofa Linn., in Ukraine.

We make new morphological observations not previously reported for the old acanthocephalan Macracanthorhynchus hirudinaceus (Pallas, 1781) Travassos, 1917, described for the first time about 240 years ago. Our specimens were collected from the wild boar, Sus scrofa Linn., in Ukraine in 2005. We provide comparative morphometrics with other populations from Ukraine, Union of Soviet Socialist Republics, Europe, Brazil and the United States of America. Our specimens from the Ukraine had the smallest trunk (110-120 mm long), longest and thickest hooks, with the third hook being the largest, largest eggs, and a proboscis wider than long. We document the morphology of the proboscis, apical organ, hooks, hook roots, sensory pores, micropores, and eggs with scanning electron microscopy for the first time. We also provide chemical analysis of hooks and eggs using energy-dispersive X-ray analysis, discuss its micropores, and provide a new molecular profile based on 18S rDNA from a European population for the first time. Edge of hook tips feature high levels of calcium and phosphorous but the high level of sulphur is mostly found in the cortical layer of eggs. One new partial 18S rDNA sequence (482 nt length) was generated from an adult specimen of M. hirudinaceus. We present the first 18S rDNA published sequence for this cosmopolitan acanthocephalan obtained from Europe. The amplified region corresponded to the approximate middle region of the small subunit ribosomal ribonucleic acid gene, which is ~1800 nt in length. This molecular contribution is especially valuable in light of the extreme scarcity of genetic information about species of Macracanthorhynchus and of the family Oligacanthorhynchidae as a whole.

Morphological and molecular description of a distinct population of Echinorhynchus gadi Zoega in Müller, 1776 (Paleacanthocephala: Echinorhynchidae) from the pacific halibut Hippoglossus stenolepis Schmidt in Alaska.

PURPOSE: Echinorhynchus gadi is one of the most widely distributed and commonly described acanthocephalans in marine fishes throughout the world. We provide a detailed morphometric and molecular description of a distinct Alaska population collected from the Pacific halibut Hippoglossus stenolepis Schmidt (Pleuronectidae) compared to those from other hosts and regions, illustrating new features never previously reported. METHODS: We described new specimens by microscopical studies, augmented by SEM, Energy Dispersive x-ray and molecular analyses, and histopathology. RESULTS: Specimens from Alaska were distinguished from those collected from the other geographical areas in proboscis size and its armature, especially number of hook rows and hooks per row, and length of hooks. The size of the receptacle, lemnisci, and reproductive structures in some other collections also varied from the Alaska material. X-ray scans of the gallium cut hooks depict prominent layering with high Sulfur content for tip cuts and increased calcium and phosphorus content in the base area of the hook. Sections of E. gadi specimens in the host tissue show prominent hook entanglement with subsequent connective tissue invasion also depicting the internal anatomy of certain worm structures not readily seen by other means. Molecular analyses clearly confirmed the identity of our E. gadi sequences. CONCLUSION: Our Alaska population of the E. gadi complex appears to represent a novel population distinguishable by its distinct morphometrics, geography and host species. We further establish new information on the Energy Dispersive X-ray analysis in our Alaska material for future comparisons with the other siblings and explore genetic relationships among echinorhynchid genera and species.

A Review of the Parasite Fauna of the Black-Bellied Pangolin, Phataginus tetradactyla LIN. (Manidae), From Central Africa with the Description of Intraproboscis sanghae n. gen., n. sp. (Acanthocephala: Gigantorhynchidae).

A new archiacanthocephalan in the family Gigantorhynchidae, Intraproboscis sanghae n. gen., n. sp. is described from females collected from the African black-bellied pangolin Phataginus tetradactyla Linn. (Manidae) in the Central African Republic. A dichotomous key to the genera of Gigantorhynchidae is provided. The specimens presented are distinct from those of the genus Gigantorhynchus Hamann, 1892 that have only 1 or 2 circles of hooks (crowns) at the apical end of the proboscis and are found in South American mammals, except for Gigantorhynchus pesteri Tadros, 1966 from baboons in Rhodesia (Zimbabwe), Africa (Amin, 2013). They superficially resemble those of the other gigantorhynchid genus Mediorhynchus Van Cleave, 1916, especially in the organization of the truncate-cone proboscis and the position of the receptacle. Species of Mediorhynchus are bird parasites. The new genus, Intraproboscis, now the third genus in Gigantorhynchidae; however, is distinguished from Mediorhynchus by having a simple proboscis receptacle that is completely suspended within the proboscis, the passage of the retractor muscles through the receptacle into the body cavity posteriorly, absence of neck, and presence of a parareceptacle structure (first finding in the Archiacanthocephala) and a uterine vesicle; among other features, including the differential dorsoventral thickness of the body wall. The receptacle in Mediorhynchus is complex, with many accessory muscles and retractor muscles passing into the body cavity dorsally and ventrally. Our specimens reached 180 mm in length and the proboscis had 34-36 rows of 6-7 ventrally lamellated, rooted hooks each anteriorly, and 15-17 spinelike hooks each posteriorly. Micropores extended into the anterior and posterior proboscis and energy dispersive x-ray analysis (EDXA) of anterior hooks showed high levels of calcium and phosphorus but negligible traces of sulfur. Spinelike hooks in the posterior proboscis had lower levels of Ca and P and slightly higher levels of S. Molecular and phylogenetic analyses based on the 18S rDNA gene placed I. sanghae in a clade with the archiacanthocephalans Mediorhynchus, Moniliformis, Macracanthorhynchus, Oncicola, and Oligacanthorhynchus.

The morphological and molecular characterization of Baylisascaris devosi Sprent, 1952 (Ascaridoidea, Nematoda), collected from Pine marten (Martes martes) in Iran.

BACKGROUND: Baylisascaris devosi is an intestinal nematode found in several carnivores including fisher, wolverine, Beech marten, American marten and sable in different parts of the world, but this nematode has not been reported from Pine marten. Therefore, this study aimed to identify Baylisascaris isolated from a Pine marten in Iran using morphological and molecular approaches. METHODS: Specimens of B. devosi were collected from one road-killed Pine marten in northern Iran. Morphological features were evaluated using scanning electron microscopy, energy dispersive x-ray analysis and ion sectioning. The molecular characterization was carried out using partial Cox1, LSU rDNA and ITS-rDNA genes. RESULTS: The nematodes isolated from the Pine marten were confirmed to be B. devosi based on the morphological features and the sequence of ribosomal and mitochondrial loci. X-ray scans (EDAX) were completed on gallium cut structures (papillae, eggs, male spike and mouth denticles) of B. devosi using a dual-beam scanning electron microscope. The male spike and mouth denticles had a high level of hardening elements (Ca, P, S), helping to explain the chemical nature and morphology of the worm. Based on these genetic marker analyses, our sequence had the greatest similarity with Russian B. devosi isolated from sable. CONCLUSIONS: In this study, to our knowledge, the occurrence of B. devosi infection in Pine marten is reported for the first time. Molecular analysis showed that these three genes are suitable molecular markers for identification and inferring phylogenetic relationships of Baylisascaris species. Furthermore, the high divergence of Cox1 between Baylisascaris species indicates that Cox1 could be used for their phylogenetic and taxonomic studies.

On the Neoechinorhynchus agilis (Acanthocephala: Neoechinorhynchidae) complex, with a description of Neoechinorhynchus ponticus n. sp. from Chelon auratus in the Black Sea.

We recognize four species in the Neoechinorhynchus agilis complex. We studied specimens of Neoechinorhynchus (Hebesoma) personatus Tkach, Sarabeev & Shvetsova, 2014 from Mugil cephalus in the Mediterranean Sea off Tunisia and in the Black Sea, and also specimens of Neoechinorhynchus ponticus n. sp. from Chelon auratus Risso in the Black Sea. Specimens from M. cephalus at both locations were similar. All structures of N. ponticus n. sp. were considerably smaller than those of N. personatus. Two other species of the N. agilis complex are recognized: Neoechinorhynchus agilis (Rudolphi, 1819) sensu stricto from various hosts in the Atlantic and the Mediterranean, and Neoechinorhynchus yamagutii Tkach, Sarabeev & Shvetsova, 2014 from M. cephalus and Planiliza haematocheila in the Pacific, especially the Sea of Japan. Neoechinorhynchus dimorphospinus Amin & Sey, 1996 from marine fish in the Persian Gulf and the Pacific Ocean off Vietnam may be a candidate for membership in the N. agilis complex. X-ray scans of gallium cut and intact hooks of N. personatus and N. ponticus showed differences in the mineral content of hooks with higher sulfur levels in smaller hooks and in hooks from specimens in the Black Sea compared to specimens from the Mediterranean. The relatively high genetic differences between N. ponticus n. sp. and other species of Neoechinorhynchus using a partial 18S rDNA dataset support its independent status. Neoechinorhynchus ponticus n. sp. and N. personatus have a common ancestor with species of Neoechinorhynchus collected from saltwater fish.

TITLE: Sur le complexe Neoechinorhynchus agilis (Acanthocephala, Neoechinorhynchidae), avec la description de Neoechinorhynchus ponticus n. sp. de Chelon auratus en mer Noire. ABSTRACT: Nous reconnaissons quatre espèces dans le complexe Neoechinorhynchus agilis. Nous avons étudié des spécimens de Neoechinorhynchus (Hebesoma) personatus Tkach, Sarabeev & Shvetsova, 2014 de Mugil cephalus en mer Méditerranée au large de la Tunisie et en Mer Noire et également des spécimens de Neoechinorhynchus ponticus n. sp. de Chelon auratus Risso en Mer Noire. Les spécimens chez M. cephalus dans les deux endroits étaient similaires. Toutes les structures de N. ponticus n. sp. étaient considérablement plus petites que celles de N. personatus. Deux autres espèces du complexe N. agilis sont reconnues: Neoechinorhynchus agilis (Rudolphi, 1819) sensu stricto provenant de divers hôtes de l'Atlantique, y compris la Méditerranée, et Neoechinorhynchus yamagutii Tkach, Sarabeev & Shvetsova, 2014 de M. cephalus et Planiliza haematocheila dans le Pacifique, en particulier la Mer du Japon. Neoechinorhynchus dimorphospinus Amin & Sey, 1996 provenant de poissons marins du golfe Persique et de l'océan Pacifique au large du Vietnam pourrait être candidat à l'appartenance au complexe N. agilis. Les radiographies des crochets coupés au gallium et des crochets intacts de N. personatus et N. ponticus ont montré des différences dans la teneur en minéraux des crochets avec des niveaux de soufre plus élevés dans les hameçons plus petits et dans les hameçons des spécimens de la Mer Noire par rapport aux spécimens de la Méditerranée. Les différences génétiques relativement élevées entre N. ponticus n. sp. et d'autres espèces de Neoechinorhynchus utilisant un ensemble de données d'ADNr 18S partiel soutiennent son statut indépendant. Neoechinorhynchus ponticus n. sp. et N. personatus ont un ancêtre commun avec des espèces de Neoechinorhynchus prélevées sur des poissons d'eau salée.

Morphological and Molecular Description of Rhadinorhynchus hiansi Soota and Bhattacharya, 1981 (Acanthocephala: Rhadinorhynchidae) from Marine Fish off the Pacific Coast of Vietnam.

Rhadinorhynchus hiansi Soota and Bhattacharya, 1981 , has remained unknown since its original incomplete description from 2 male specimens collected from the flat needlefish Ablennes hians Valenciennes (Belonidae) off Trivandrum, Kerala, India. Recent collections of fishes along the Pacific coast of Vietnam in 2016 and 2017 produced many specimens of the same species from the striped bonito Sarda orientalis Temminck and Schlegel (Scombridae) off the southern Pacific coast of Vietnam at Nha Trang. We describe females for the first time, assign a female allotype status, and provide an expanded description of males from a larger collection completing missing information on hooks and hook roots, receptacle, lemnisci, cement glands, Saefftigen's pouch, and trunk spines. Specimens of R. hiansi characteristically have no dorsal spines in the posterior field of trunk spines and a long proboscis with 36-48 dorso-ventrally differentiated proboscis hooks per row becoming progressively smaller posteriorly then increasing in size near the posterior end to a maximum at the posterior-most ring. Trunk, testes, and lemnisci in our specimens were considerably larger than those reported in the original description, but the proboscis was relatively smaller. The females had long reproductive system and corrugated elliptic eggs without polar prolongation of fertilization membrane. Energy Dispersive X-ray Analysis (EDXA) demonstrates high levels of calcium and phosphorus in large gallium cut hooks and high levels of sulfur in tip cuts of large and small hooks and in spines. This EDXA pattern is a characteristic fingerprint of R. hiansi. The molecular profile of R. hiansi is described from 18S rDNA and COI genes, and phylogenetic relationships with most closely related species are discussed.

Morphological updates and molecular description of Heterosentis holospinus Amin, Heckmann, & Ha, 2011 (Acanthocephala, Arhythmacanthidae) in the Pacific Ocean off Vietnam.

Heterosentis holospinus Amin, Heckmann & Ha, 2011 (Arhythmacanthidae) was first described from the striped eel catfish, Plotosus lineatus (Plotosidae) in Halong Bay, Vietnam. New morphological information, scanning electron microscope images, molecular analysis, and Energy Dispersive X-ray analysis (EDXA) of hooks of specimens of H. holospinus from a new collection from the common ponyfish, Leiognathus equulus (Leiognathidae), in Quang Binh, Gulf of Tonkin, Vietnam are reported here for the first time. Additional details of the anterior trunk cone, proboscis hooks, wholly spined trunk, duck-bill-like spines with micropores, and micropore distribution, are described. The unique metal composition of hooks (EDXA) demonstrated a considerably higher level of calcium and phosphorus but lower level of sulfur at the hook basal arch than at the hook tip and edge. An analysis of our new sequences of cytochrome oxidase 1 (COI) showed that H. holospinus had low genetic variation and two haplotypes.

TITLE: Mise à jour morphologique et caractérisation moléculaire d'Heterosentis holospinus Amin, Heckmann & Ha, 2011 (Acanthocephala, Arhythmacanthidae) de l'Océan Pacifique au large du Vietnam. ABSTRACT: Heterosentis holospinus Amin, Heckmann & Ha, 2011 (Arhythmacanthidae) a été décrit pour la première fois chez le poisson-chat Plotosus lineatus (Plotosidae) dans la baie d'Halong, au Vietnam. Des nouvelles informations morphologiques, des images au microscope électronique à balayage, une analyse moléculaire et une analyse par rayons X à dispersion d'énergie (EDXA) des crochets de spécimens d'H. holospinus provenant d'une nouvelle récolte de Leiognathus equulus (Leiognathidae), à Quang Binh, golfe du Tonkin, Vietnam sont données pour la première fois. Des détails supplémentaires sur le cône antérieur du tronc, les crochets du proboscis, le tronc entièrement épineux, les épines en forme de bec de canard avec des micropores et la distribution des micropores sont décrits. La composition métallique unique des crochets (EDXA) a démontré une teneur en calcium et en phosphore considérablement plus élevée, mais une teneur en soufre plus faible au niveau de l'arcade basale du crochet qu'à la pointe et au bord du crochet. Une analyse de nos nouvelles séquences de cytochrome oxydase 1 (COI) a montré qu'H. holospinus présentait une faible variation génétique et deux haplotypes.

Description of Acanthocephalus anguillae balkanicus subsp. n. (Acanthocephala: Echinorhynchidae) from Proteus anguinus Laurenti (Amphibia: Proteidae) and the cave ecomorph of Asellus aquaticus (Crustacea: Asellidae) in Slovenia.

Acanthocephalus balkanicus Batchvarov et Combes, 1974 was incompletely described from the northern crested newt, Triturus cristatus (Laurenti) (Amphibia: Salamandridae), a possible synonym of the Balkan crested newt, Triturus ivanbureschi Arntzen et Wielstra, from a pond in village of Pesnopoy, southern Bulgaria. We provide a full description of adult males and females of the same taxon from the olm, Proteus anguinus Laurenti (Amphibia: Proteidae), the only exclusively aquatic cave-dwelling vertebrate in Europe, captured in Postojna-Planina Cave System in Slovenia. Cystacanths were also collected from the cave ecomorph of Asellus aquaticus (Linnaeus) (Crustacea: Asellidae) in the same location. Molecular analysis of specimens from Slovenia revealed that they are genetically almost identical to those of Acanthocephalus anguillae (Müller, 1780), a common parasite of European freshwater fishes. We propose to recognise the morphological and host differences by describing A. balkanicus as a new subspecies of A. anguillae. Acanthocephalus anguillae balkanicus is rather small and cylindrical with cylindrical proboscis having 10 rows of 6 hooks with simple roots each, long neck, large balloon-shaped lemnisci, small spherical anterior testis, and 6 club-shaped cement glands in 3 pairs. SEM images reveal more morphological details and the X-ray scans of gallium cut hooks shows considerably higher levels of phosphorus and calcium in adult hooks than in cystacanth hooks, especially in basal areas. Sulfur levels were higher in the arch and basal area of cystacanth hooks than adult hooks. Considering that both definitive and intermediate hosts of the Slovenian population of this acanthocephalan are bound to cave life, it is possible that its entire life cycle is uniquely completed underground.

The Morphological and Molecular Description of Acanthogyrus (Acanthosentis) fusiformis n. sp. (Acanthocephala: Quadrigyridae) from the Catfish Arius sp. (Ariidae) in the Pacific Ocean off Vietnam, with Notes on Zoogeography.

BACKGROUND: Most (82%) of the 46 recognized species of Acanthogyrus (Acanthosentis) Verma and Datta, 1929 are known from Asian freshwater fishes. Only three species of Acanthosentis are known from marine or brackish water fishes from India and Pakistan. We have discovered another marine species of Acanthosentis in the Pacific Ocean, off Vietnam. PURPOSE: The purpose is to describe the new species morphologically and molecularly and provide new information of its evolutionally relationships with other species of the subgenus. METHODS: Standard methods of collection and examination of marine hosts, processing and illustrating of specimens, and taxonomic identification of parasites using the extensive collection of the lead author were used. Specimens were further studied using energy-dispersive X-ray analysis and ion sectioning of hooks, SEM analysis, and molecular sequencing. Type specimens were deposited at the Harold W. Manter Lab. collection, Lincoln, Nebraska. RESULTS: Acanthogyrus (Acanthosentis) fusiformis n. sp. is described from the catfish, Arius sp. (Ariidae: Siluriformes) off the Pacific Coast of Vietnam at Bac Lieu in the Gulf of Thailand. The three other marine Indian species include A. (A.) arii Bilqees, 1971 which is also described from a similar catfish, Arius serratus Day off the Karachi coast in the Arabian Sea, Indian Ocean. Our new species from Vietnam is distinguished from the other 46 species by a combination of characters including a small fusiform trunk, complete circles of small hollow spines covering the entire trunk, prominent double apical organs often extending posteriorly past posterior hooks, middle and posterior hooks of equal size slightly smaller than anterior hooks, large neck continuous with the outline of the proboscis without distinct separation, big drop-shaped cephalic ganglion, extension of the proboscis receptacle anteriorly past the base of the proboscis up to the insertion point of the posterior hooks, presence of two para-receptacle structures (PRSs), free unattached thick lemnisci, short female reproductive system with filamentous attachment of the distal end of the uterine bell to the ventral body wall, and small narrowly ellipsoid eggs with thickened polar ends. Partial sequences of the 18S and internal transcribed spacers (ITS1-5.8S-ITS2) of ribosomal RNA were generated and used for phylogenetic analyses to confirm the taxonomic identity of Acanthogyrus (Acanthosentis) fusiformis n. sp. CONCLUSIONS: We describe unique morphological features of A. fusiformis never before known in the subgenus Acanthosentis. The uniqueness of A. fusiformis is further demonstrated by its EDXA fingerprint characterized by high levels of calcium and phosphorous in hooks. The zoogeography of species of Acanthosentis is elucidated in the Indian subcontinent, the Caribbean, China, and Africa. Molecular data have been available only in few species of Acanthogyrus (Acanthosentis) to date on GenBank database. For 18S, only two sequences from unknown Acanthosentis sp. from India are available, while for the ITS1-5.8S-ITS2 region, only sequences of A. cheni from China and of two unidentified species from Malaysia are available. Additional studies of species of Acanthosentis based on morphological and molecular genetic data will be needed to reconstruct the evolutionary history and phylogenetic affinities of this group of acanthocephalans.

Moniliformis cryptosaudi n. sp. (Acanthocephala: Moniliformidae) from the Long-eared Hedgehog Hemiechinus auritus (Gmelin) (Erinaceidae) in Iraq; A Case of Incipient Cryptic Speciation Related to M. saudi in Saudi Arabia.

Moniliformis cryptosaudi n. sp. (Moniliformidae) is an acanthocephalan described from the long-eared hedgehog Hemiechinus auritus (Gmelin) (Erinaceidae) in Iraq as an incipient cryptic species of Moniliformis saudi Amin, Heckmann, Mohammed, Evans, 2016 described from the desert hedgehog Paraechinus aethiopicus (Ehrenberg) (Erinaceidae) in Saudi Arabia. Microscopical studies demonstrate that the two species are morphologically indistinguishable with practically identical measurements and counts but differed significantly in their energy dispersive X-ray analysis (EDXA) of metal composition of hooks. Hooks of specimens of the new species appeared to be of collagen material with very low levels of phosphorus and calcium unlike those of M. saudi and Moniliformis kalahariensis Meyer, 1931 that had high levels of calcium and phosphorus. Using 18S rDNA and cox1 genes, M. Saudi and M. kalahariensis were shown to be molecularly distinct but the molecular profiles of M. saudi and M. cryptosaudi were more similar. The molecular profile of M. kalahariensis collected from the South African hedgehog Atelerix frontalis Smith (Erinaceidae) in South Africa is reported for the first time and is studied only for comparative purposes. Moniliformis saudi and M. kalahariensis had comparable EDXA metal analysis that was distinct from that of M. cryptosaudi.

Descriptions of two new acanthocephalans (Rhadinorhynchidae) from marine fish off the Pacific coast of Vietnam.

Two rhadinorhynchid acanthocephalans are described from marine fishes off the Pacific coast of Vietnam. Sclerocollum neorubrimaris n. sp. (Gorgorhynchinae Van Cleave & Lincicome, 1940) is described from the spine-foot rabbitfish Siganus guttatus (Bloch) (Siganidae) off Nha Trang. The new species is similar to the type-species, Sclerocollum rubrimaris Schmidt & Paperna, 1978 in most measurements and counts but has a posterior cephalic ganglion, a sub-ventral female gonopore, and one dorsal paravaginal filament bundle. In S. rubrimaris, the cephalic ganglion is near the middle of the receptacle, the female gonopore is terminal with two paravaginal filament bundles. The new species is distinguished from three other species of Sclerocollum Schmidt & Paperna, 1978 in proboscis hook formulas and the position of the female gonopore and cephalic ganglion. The issue of the importance of the position of the cephalic ganglion at the generic and sub-generic levels in the Acanthocephala is discussed. Females of Australorhynchus multispinosus n. sp. (Gorgorhynchinae) are described from the red cornetfish Fistularia petimba Lacépède off Nha Trang in the Pacific south. It is distinguished from the only other species of the genus, Australorhynchus tetramorphacanthus Lebedev, 1967, by having more trunk spines extending beyond the level of the proboscis receptacle and a smaller proboscis with considerably fewer hooks.

Morphological Studies of Developmental Stages of Oculotrema hippopotami (Monogenea: Polystomatidae) Infecting the Eye of Hippopotamus amphibius (Mammalia: Hippopotamidae) Using SEM and EDXA with Notes on Histopathology.

The present study was performed to observe histopathological effects of Oculotrema hippopotami Stunkard, 1924 infection in the eye of Hippopotamus amphibius, as well as to reveal new details of morphology and structural features of this monogenean and its comparison between 2 age stages of the parasite. This was done using both light and scanning electron microscopy, energy dispersive X-ray analysis (EDXA) and histopathology. The presence of a mixture of different generations (adult and sub-adult) in one host individual is common for Oculotrema Stunkard, 1924 in contrast to Polystoma Zeder, 1800. New metrical and graphical information obtained for adults and sub-adults compared with the previous studies. Here we show the presence of genital papillae in adults, metrical data on the distal part of the vas deferens. SEM micrographs of sperm ejaculatory structures and information about the flattened dorsal side of the body provided for the first time. Histopathological changes, such as necrosis and hemorrhage in host tissues as a result of O. hippopotami attachment structures are described. Structural analysis of different body parts of O. hippopotami of both age groups are also included. We show qualitative differences in the presence of hardening ions (S, P, Ca) in attachment structures (oral and haptor suckers) that increase with the age of the worm. The presence of sub-adults and adults on the same host, together with high levels of infection without high pathogenicity may account for Oculotrema being one of the most successful parasites among the Monogenea.

Descriptions of Acanthocephalus parallelcementglandatus (Echinorhynchidae) and Neoechinorhynchus (N.) pennahia (Neoechinorhynchidae) (Acanthocephala) from amphibians and fish in Central and Pacific coast of Vietnam, with notes on N. (N.) longnucleatus.

Three species of acanthocephalans are described from fishes caught in the Pacific coast off eastern Vietnam and from amphibians in the midlands in 2016: (1) Acanthocephalus parallelcementglandatus Amin, Heckmann, Ha, 2014 (Echinorhynchidae), described from 1 male specimen is now fully described from males and females collected from 2 species of amphibians, the similar frog Hylarana attigua Inger, Orlov, Darevsky and the odorous frog Odorrana sp. Fei, Ye, Huang (Ranidae) in Huong Thuy, Hue City and Chu Yang Sin Park, central Vietnam, respectively, as well as from the needlefish Tylosurus sp. Cocco (Belonidae) in Binh Thuân in the Pacific South. The allotype female is designated. Neoechinorhynchus (N.) pennahia Amin, Ha, Ha, 2011 described from 1 female specimen is now fully described from males and females collected from the Toli shad (Chinese herring), Tenualosa toli (Valenciennes) (Clupeidae) in the Pacific north coast off Haiphong. The allotype male is designated. One specimen of Neoechinorhynchus (Neoechinorhynchus) longnucleatus Amin, Ha, Ha, 2011 is also reported from the common ponyfish, Leiognathus equulus (Forssskål) (Leiognathidae) in the Pacific south coast of Nha Trang and its ecology briefly discussed.

Descriptions of acanthocephalans, Cathayacanthus spinitruncatus (Rhadinorhynchidae) male and Pararhadinorhynchus magnus n. sp. (Diplosentidae), from marine fish of Vietnam, with notes on Heterosentis holospinus (Arhythmacanthidae).

Males of Cathayacanthus spinitruncatus Amin, Heckmann & Ha, 2014 (Rhadinorhynchinae Lühe, 1912) are described for the first time from Leiognathus equulus in Hai Phong and Nha Trang and from pony fish Nuchequula flavaxilla in Quang Ninh in the Pacific waters of Vietnam. The male allotype status is designated. Males of C. spinitruncatus are smaller and have fewer and smaller proboscis hooks and trunk spines than females. The male reproductive structures are in the posterior fifth of the trunk and with 6 club-shaped cement glands gradually merging into 6 independent cement gland ducts. The proboscis receptacle is more than half as long as the trunk and with a cephalic ganglion at its anterior end. In females, the receptacle is only about one fifth the length of the trunk. Specimens described as Cathayacanthus bagarii Moravec & Sey, 1989 were shown to have been wrongly assigned to Cathayacanthus. Pararhadinorhynchus magnus n. sp. (Diplosentidae) is described from Scatophagus argus off Hai Phong in the Gulf of Tonkin. It is the third species of the genus and is readily distinguished from the Australian species by having a considerably larger trunk and male reproductive structures, and more proboscis hooks. X-ray microanalysis (EDAX) of intact and gallium-cut hooks of P. magnus showed high calcium and phosphate mainly in the central core. Specimens of Heterosentis holospinus Amin, Heckmann & Ha, 2011 (Arhythmacanthidae) are also reported from L. equulus off Quang Binh, new host and locality records.

Descriptions of Neorhadinorhynchus nudum (Cavisomidae) and Heterosentis paraholospinus N. SP. (Arhythmacanthidae) (Acanthocephala) From Fish Along the Pacific Coast of Vietnam, With Notes On Biogeography.

Two species of acanthocephalans are described from fishes caught along the Pacific coast off eastern Vietnam in 2016: (1) Neorhadinorhynchus nudum ( Harada, 1938 ) Yamaguti, 1939 (Cavisomidae) from the frigate tuna Auxis thazard (Lacépède) (Scombridae) in Nha Trang, Pacific south Vietnam, and (2) Heterosentis paraholospinus n. sp. (Arhythmacanthidae) from 3 species of fish: the common ponyfish Leiognathus equulus (Forsskål) (Leiognathidae) and the torpedo scad Megalaspis cordyla (Linn.) (Carangidae) off Nha Trang and Binh Thuân, respectively, and the yellowspotted ponyfish Nuchequula flavaxilla Kimura, Kimura, and Ikejima (Leiognathidae) at Quang Ninh in Pacific waters of Vietnam. Females of N. nudum are fully described for the first time in the Pacific Ocean. Heterosentis paraholospinus n. sp. is similar to Heterosentis holospinus Amin, Heckmann, and Ha, 2011, in having an unspined anterior trunk cone, nucleated pouch at the posterior end of the receptacle, and spines covering the entire trunk, but it differs in having a long cylindrical trunk, lemnisci much longer than the receptacle, more and different-sized proboscis hooks, and subterminal female gonopore. Biogeographical notes are discussed for both genera.

Cavisoma magnum (Cavisomidae), a unique Pacific acanthocephalan redescribed from an unusual host, Mugil cephalus (Mugilidae), in the Arabian Gulf, with notes on histopathology and metal analysis.

Cavisoma magnum (Southwell, 1927) Van Cleave, 1931 was originally described from a sea bass, Serranus sp. and spotted surgeonfish, Ctenochaetus strigosus (Perciformes) off Sri Lanka before its more recent redescription from milkfish in the Philippines in 1995. These reports were based on only light infections of their host fishes. Of the few flathead grey mullets, Mugil cephalus (Mugilidae), that we examined in the Arabian Gulf, one fish was infected with 1,450 worms. One milkfish, Chanos chanos (Chanidae), from the same location in the Arabian Gulf, was also heavily infected with specimens of C. magnum. The descriptions of this unique large worm are revised and for the first time, we provide SEM images, new systematic observations, metal analysis of hooks showing extremely high levels of sulfur, and histopathology in the mullet intestinal tissue. Adjustments and corrections of previous descriptive accounts are made. The histopathology studies show extensive damage to the host intestinal tissue including epithelial necrosis, hemorrhaging and worm encapsulation. There is an extensive amount of host connective tissue surrounding the worm. Results of x-ray analysis displayed high levels of sulfur in proboscis hooks, especially at the tips and edges of these attachment structures.