Description and pathology of Neoechinorhynchus idahoensis n. sp. (Acanthocephala: Neoechinorhynchidae) in Catostomus columbianus from Idaho.

Neoechinorhynchus idahoensis is described from Catostomus columbianus caught in the Salmon River, Stanley Basin, Idaho. The new species is closest to Neoechinorhynchus venustus Lynch, 1936, but is distinguished from it by its smaller and variably structured eggs, anterio-dorsal trunk hump, bent and posteriorly notched proboscis receptacle, and larger proboscis, proboscis receptacle, and hooks. It is distinguished also from 2 other species of Neoechinorhynchus with proboscis hooks in middle and anterior circles about equally large and from 7 other species having lemnisci greatly unequal in length. Histopathology of host tissue showed limited host response exemplified by epithelial damage and hemorrhaging at point of proboscis attachment with subsequent macrophage and other phagocytic cell migration. The proboscis extended through the host epithelium into the submucosa with limited hemorrhaging at the point of attachment. Unorganized collagenous fibers were present. The lumen of the host intestine was obstructed, and compressed villi were present. The trunk of the worm damaged intestinal epithelium near the crypts, causing localized inflammation. The caryophyllaeid cestode Isoglaridacris calentinei Mackiewicz, 1974, was present in concurrent infections of C. columbianus.     

Pomphorhynchus patagonicus n. sp. (Acanthocephala: Pomphorhynchidae) from freshwater fishes of Patagonia, Argentina

Pomphorhynchus patagonicus n. sp. is described from Lake Rosario, Chubut Province, Argentina. It is characterized by a long neck forming an asymmetrical bulb with 2 well differentiated dorsal protruberances and 14 alternating rows of 13 and 14 proboscis hooks, each row with a stout fourth hook. It most closely resembles Pomphorhynchus sebastichthydis Yamaguti, 1939, from Japan, but differs in the bulb protruberances and in having more rows of hooks and more hooks per row and in the shapes of the fourth and basal hooks. Among American species P. patagonicus shows some similarities to Pomphorhynchus yamagutii Schmidt and Hugghins, 1973, from Chile, but differs with respect to the longer neck, bulb protruberances, and proboscis armature. Pomphorhynchus patagonicus is endemic to Patagonia, where its definitive type host is the endemic fish Patagonina hatcheri (Atherinidae) and its intermediate host the endemic freshwater amphipod Hyalella patagonica. It has been found also in autochthonous fishes belonging to the families Galaxiidae and Percichthyidae and in introduced salmonid fishes.     

Erection of Ibirhynchus gen. nov. (Acanthocephala: Polymorphidae), based on molecular and morphological data

The genus Southwellina is composed of 3 described species, i.e., S. hispida (the type species), S. dimorpha, and S. macracanthus. All 3 are endoparasites of fish-eating birds that have worldwide distributions. Morphologically, the genus is characterized by possessing a short and compact trunk, 2 fields of spines in the anterior region of the trunk (in at least 1 sex), a short cylindrical proboscis (sometimes with a swollen region armed with numerous longitudinal rows of hooks), a double-walled proboscis receptacle, and 4 tubular cement glands in males. In the current study, specimens identified as S. dimorpha were collected from Eudocimus albus (white ibis), the type host from the Gulf of Mexico. Sequences of 2 nuclear genes (small subunit [SSU] and long subunit [LSU] ribosomal DNA) and 1 mitochondrial gene (cytochrome c oxidase subunit 1 [cox 1]) of S. dimorpha and S. hispida were obtained and used to reconstruct the phylogenetic relationships of both species with respect to published sequences of 11 species representing 6 genera of Polymorphidae. Maximum parsimony (MP) and maximum likelihood (ML) analyses of the concatenated data set (SSU + LSU + cox 1) were identical in depicting Southwellina as paraphyletic, indicating that the genus should be revised. The MP and ML trees identified S. hispida as a sister to Polymorphus brevis, whereas S. dimorpha was a sister to Hexaglandula corynosoma. Morphologically, S. dimorpha is distinct from H. corynosoma, which is characterized by a short trunk with 1 field of spines in the anterior part of the trunk in both genders, and males with 6 tubular cement glands. The genetic divergence estimated from a concatenated data set between 2 isolates of S. hispida and S. dimorpha ranged from 10.7 to 11.0%. This range of genetic divergence is similar to that found among other genera of Polymorphidae, which extends from 6.0 to 12.0%. Southwellina dimorpha differs from S. hispida in the shape of the proboscis and the presence of 1 field of spines (S. dimorpha) versus 2 fields (S. hispida) on the anterior region of the trunk in females. Based on the phylogenetic position of S. dimorpha within Polymorphidae, coupled with levels of genetic divergence and, more importantly, the morphological and ecological (host specificity) differences, we propose the erection of a new genus to accommodate S. dimorpha.     

Spiracanthus bovichthys n. gen. n. sp. (Acanthocephala: Arhythmacanthidae), a parasite of littoral fishes of the central south coast of Chile

A new acanthocephalan species, Spiracanthus bovichthys n. gen. n. sp., is described. Samples were taken from 26 marine fish species between 23 and 53 degrees S of Chile. The parasite was found in the intestine of 6 species and only between 36 and 40 degrees S, especially in those fish that prey on small crustaceans in the upper and sublittoral zone. The parasite was found in Bovichthys chilensis (Reagan). Auchenionchus variolosus (Valenciennes), Calliclinus genigutattus (Valenciennes), Sindoscopus australis (Fowler and Bean), Myxodes cristatus Valenciennes, and Gobiesox marmoratus (Jenyns). However, only the first species is a suitable host for the parasite as evidenced by the presence of mature females. This acanthocephalan belongs to Arhythmacanthidae, but it does not correspond to any genus described. Spiracanthus bovichthys is different in the number and spiralled distribution of its hooks in the proboscis. In the short proboscis, 3 groups of hooks are distinguished according to size, summing up to 150-190 hooks. The group of largest hooks are found in the apical part of the proboscis, and there are 10 diagonal rows of small hooks from the prebasal to basal proboscis. Its trunk is covered partially by small spines. Amphipod and isopods were the prey items shared among the host fish species and are the best candidates to be the intermediate hosts of S. bovichthys.     

Acanthocephalus tahlequahensis sp. n. (Acanthocephala: Echinorhynchidae) from the the stippled darter, Etheostoma punctulatum (Agassiz), in northeastern Oklahoma.

Acanthocephalus tahlequahensis sp. n. was recovered from the intestines of 4 species of freshwater fishes, Etheostoma punctulatum, E. spectabile, Nocomis asper, and Notropis pilsbryi, collected in northeastern Oklahoma. The new species is distinguished from all other species of Acanthocephalus, except A. japonicus (Fukui and Morisita 1936) Petrochenko 1956, and A. fluviatilus Paperna 1964, by having smaller proboscis hooks. The length of the proboscis hooks for males is 27 to 38 (33) mum and for females 35 to 46 (42) mum. A. tahlequahensis is smaller than either A. japonicus or A. fluviatilis, and has about half the number of longitudinal rows of proboscis hooks of A. japonicus and half the number of proboscis hooks in each longitudinal row of A. fluviatilus. In addition to having smaller hooks. A. tahlequahensis differs from other species of Acanthocephalus parasitizing North American fishes by its smaller, spindle-shaped trunk and more hooks in each longitudinal row.     

New morphological data on the acanthocephalan <Emphasis Type="Italic">Hypoechinorhynchus magellanicus</Emphasis> Szidat, 1950 (Palaeacanthocephala: Arhythmacanthidae)

Hypoechinorhynchus magellanicus Szidat, 1950 (Acanthocephala: Arhythmacanthidae) is redescribed based on specimens collected from a sub-Antarctic notothenioid fish, Champsocephalus esox (Günther). The host was caught in the Beagle Channel (Magellanic sub-region). H. magellanicus has a trunk with an antero-dorsal curvature, a spherical proboscis, spines on the anterior region of the trunk, narrow lemnisci which are considerably longer than the proboscis receptacle, six cement glands and a single vaginal sphincter. The proboscis is armed with 40 hooks, including 15 large hooks with roots and 25 rootless basal spines. The large hooks are arranged in 10 alternate rows of one and two hooks. Each single large hook is followed by two spines, and pairs of large hooks are followed by single spines. Ten single spines are also present at the base of the proboscis between the rows. The eggs have polar prolongations of the middle envelope.     

Ultrastructural study of the host-parasite interface of Moniliformis moniliformis (Archiacanthocephala) in laboratory-infected rats

The fine structure of the host-parasite interface of Moniliformis moniliformis in rats is described, comprising investigations on the ontogenic development of the presomal tegument, on the lesions caused by the worms, and on the host cellular reactions at the points of attachment of the worm. The presomal tegument of the worm contained more fibrous elements than the metasomal tegument. The sclerotization increased with the ages of the worms and toward the tip of the proboscis. The presomal surface coat was more coarsely structured and osmiophilic than that of the metasoma and was neither continuous with the contents of the tegumental crypts nor supported by lipids from necrotic host tissue. The surface coat occasionally detached from the proboscis, probably due to the activity of the surrounding granulocytes of the host. The proboscis hooks lost their tegumental covering during their larval development. Hooks of all worms from rats were invested with a semiliquid lipid coat, apparently derived from tegumental excretions at the base of the hooks. The invaginated area of excretion around the base of the hooks was rich in endoplasmic reticulum. The hooks seemed to renew their lipid coats at certain intervals by dipping into the excreted lipid. In rats all worms, irrespective of their age, attached superficially, penetrating only the intestinal mucosa and the tunica propria. No fibrous connective tissue was found in the lesions caused by the worms, indicating that they frequently changed their site of attachment. At 3-10 days postinfection the host's defense cells observed in the lesions consisted mainly of granulocytes, whereas plasma cells were the predominant leukocytes in lesions of older infections.     

Acanthocephaloides cyrusi n. sp. (Acanthocephala: Arhythmacanthidae) from southeast African teleost fishes

A new species,Acanthocephaloides cyrusi, is described from the fishesSolea bleekeri andPomadasys commersoni from Lake St. Lucia, Natal, South Africa. It is distinguished from the other species in the genus by the more marked sexual dimorphism in length, the arrangement of hooks, the proboscis with the longest hooks at the anterior-most extremity and the greater size of the proboscis hooks and body spines. An acanthella, which may represent this species, was found in the tanaidApseudes digitalis.     

Description and morphological variability of <Emphasis Type="Italic">Neoechinorhynchus beringianus</Emphasis> n. sp. (Acanthocephala: Neoechinorhynchidae) from north-eastern Asia

Neoechinorhynchus beringianus sp. n. is described from Pungitius pungitius L. in north-eastern Russia. Since 1986, when it was first found, it was reported as 'N. pungitius Dechtiar, 1971'. However, this new species differs from the latter in having an egg shell without a prolongation of the fertilisation membrane, a larger proboscis and proboscis hooks, a subterminal position of the female genital pore and a more slender trunk, and it occurs in a different site in the intestine. N. beringianus has a small, stout body with an asymmetrical position of the proboscis, which is located ventrally to and at an angle with the longitudinal axis of the body. The proboscis is wider than long, the hooks are of equal size in each circle but diminish in size posteriorly, whereas the lemnisci are subequal in length. It differs from those species of Neoechinorhynchus Stiles & Hassall, 1905 with somewhat similar characteristics in body length, proboscis size and proportions, proboscis hook lengths, egg size, size-ratio of the cement gland and testes, and the number of giant nuclei in the tegument and lemnisci. In different geographical populations of the new species, the sizes of both the proboscis and proboscis hooks exhibit some variation.     

Acanthocephalus?amini n. sp. (Acanthocephala: Echinorhynchidae) from the freshwater fish Cichlasoma?urophthalmus (Günther) (Cichlidae) in Mexico

Acanthocephalus amini n. sp. (Palaeacanthocephala: Echinorhynchidae) is described from the intestine of Cichlasoma urophthalmus (Günther) (Pisces: Cichlidae) collected in the Río Champotón, a river in Campeche State, Mexico. It is the fourth species of Acanthocephalus Koelreuther, 1771 described from North American freshwater fishes, although two other species are known from South America. The new species is distinguished from other members of Acanthocephalus by features of its trunk, which is small, clavate, slightly expanded medially and bluntly pointed posteriorly. It is further distinguished by having a cylindrical proboscis armed with 13–14 longitudinal rows of 11–12 stout hooks; the apical and medial proboscis hooks are almost uniform in size and shape, decreasing in size towards the base; the posteriormost hooks are smaller, straighter and more slender than the anterior and middle hooks; and the lateral rows of hooks are more widely spaced, forming a conspicuous longitudinal area devoid of hooks. Furthermore, the lemnisci are saccate and shorter than the proboscis receptacle; and the neck is very short with a thick collar of trunk tegument, which encircles the base of proboscis. In males, the testes are in the middle third of trunk, diagonal, spherical and small relative to the body size, and there are six clavate cement glands. In females, the uterus forms a conspicuous, elongate, cylindrical egg reservoir. The new species is most similar to A. alabamensis Amin & Williams, 1983, but can be distinguished by its swollen, clavate trunk, the largest proboscis hooks being present apically and medially, smaller testes, a shorter male reproductive system relative to body size and females with a prominent uterus. They have different hosts and geographical distribution. The new species can be differentiated from Brasacanthus sphoeroides Thatcher, 2001, a similar species in a monotypic echinorhynchid genus, because the latter is larger, has smaller proboscis hooks and its lemnisci are longer than the receptacle.     

Cystacanths of Acanthocephala in notothenioid fish from the Beagle Channel (sub-Antarctica)

The morphology of relaxed cystacanths of polymorphid acanthocephalans collected from notothenioid fishes in the Beagle Channel (Magellanic subregion of sub-Antarctica) is described. A parasite of birds, Andracantha baylisi (Zdzitowiecki, 1986), was found in Patagonotothen longipes and Champsocephalus esox. It has: a proboscis 0.82–0.89 mm long; a proboscis hook formula of 16 rows of 9/10–10/11, including 4–5 basal hooks; distal hooks with the longest blades; a fore-trunk not separated from the hind-trunk by a constriction; large somatic spines arranged in two zones separated by a zone of small, loosely dispersed spines; and only the anterior 36–40% of ventral side of the trunk is covered with spines. One male specimen of Corynosoma sp. was found in Patagonotothen tessellata. It differs from A. baylisi in that the distal proboscis hooks are similar in length to the prebasal hooks, it has a smaller proboscis (0.77 mm) and in the distribution of the somatic spines, which are contiguous with the genital spines on the ventral side of the trunk and lack a zone of small spines between zones of larger spines. A parasite of seals and fur seals, Corynosoma evae Zdzitowiecki, 1984, was found in P. longipes and Champsocephalus esox. It has: a proboscis 0.61–0.78 mm long; a proboscis hook formula of 20–22 rows of 12–13, including 3/4–4 basal hooks; prebasal hooks with the longest blades; a trunk divided into fore-trunk and hind-trunk; somatic spines covering the anterior 64–74% of the ventral side of the trunk; genital spines present only in males; and a terminal genital opening in both sexes. Corynosoma beaglense n. sp. was found in Champsocephalus esox. It has: an almost cylindrical proboscis (length 0.52–0.56 mm); a proboscis hook formula of 16 rows of 9/10–10/11, including 4–4/5 basal hooks; distal hooks shorter than the prebasal hooks; a fore-trunk not separated from the hind-trunk by a constriction; somatic spines contiguous with the genital spines on the ventral side of the trunk of the male and covering the entire length of the ventral side of the female trunk, and the presence of genital spines surrounding the terminal genital pore of the male. The definitive host of this species is unknown.     

Porrorchis nickoli n. sp. (Acanthocephala:: Plagiorhynchidae) from mammals in southeastern Mexico,first known occurrence of Porrorchis in the western hemisphere

Porrorchis nickoli n. sp. is described from the intestine of the gray four-eyed opossum Philander opossum (type host), the Virginia opossum Didelphis virginiana, the common opossum Didelphis marsupialis, and the white-nosed coati Nasua narica. Hosts were collected in southeastern Mexico in the Los Tuxtlas region of the state of Veracruz (type locality) and in the states of Tabasco and Chiapas. This new species is distinguished from other Porrorchis species by its small proboscis (0.286-0.428 mm long x 0.273-0.438 mm wide), a proboscis armature consisting of 22-24 vertical rows of 7 or 8 hooks per row, and the male reproductive system extending postequatorially and occupying only half of the trunk. This is the first known occurrence of a Porrorchis species in the Western Hemisphere.     

Amapacanthus amazonicus n. g., n. sp. (Acanthocephala: Diplosentidae: Allorhadinorhynchinae) from Arius passany and Anableps microleps (Pisces) at Maraca Island off northern Brazil

Amapacanthus amazonicus n. g., n. sp. is described from the intestine of Arius passany (Valenciennes) and Anableps microleps Müller. The most important diagnostic features are: a small globular proboscis armed with 6 diagonal rows of 3 stout hooks; middle hooks conspicuously stouter and larger than anterior ones; terminal hooks as long as middle hooks but straighter and more slender; a double-walled proboscis receptacle; a trunk bearing spines anteriorly; and two tubular cement glands in the males. Amapacanthus n. g. is differentiated from Allorhadinorhynchus, Golvanorhynchus and Slendrorhynchus, the other genera of the Allorhadinorhynchinae, by the presence of a globular proboscis armed with a small number (18) of hooks. A key to the species of the Allorhadinorhynchinae is presented.     

A new species of Heterosentis Van Cleave, 1931 (Acanthocephala, Arhythmacanthidae), a parasite of pinguipedid fishes in the southwest Atlantic

A new species of arhythmacanthid acanthocephalan, Heterosentis martini n. sp., parasitic in the Argentinean sandperch Pseudopercis semifasciata (Cuvier) (Perciformes, Pinguipedidae) from the coasts of Argentina is described. Heterosentis martini n. sp. differs from all congeneric species by having 10 longitudinal rows of hooks in the proboscis, each with 7-8 hooks, consisting of 1 medium apical and 3 larger sub-apical hooks with root, and 3-4 smaller, basal, curved hooks with rudimentary roots and spines in both ventral and dorsal regions of the body. The most similar species, Heterosentis heteracanthus (Linstow, 1896) Van Cleave, 1931, and Heterosentis brasiliensis Vieira, Felizardo and Luque, 2009, also have 10 longitudinal rows of hooks, but H. heteracanthus differs from the new species by having only 3-5 (more frequently 4) hooks in each row, with only the anterior hook large and bearing a developed root. Heterosentis brasiliensis differs from the new species by possessing 2 sub-apical hooks in each row (instead of 3), similar body length but shorter proboscis, and trunk spines restricted to the ventral surface of body.     

Host-parasite interface of Paratenuisentis ambiguus (Eoacanthocephala) in naturally infected eel and in laboratory-infected sticklebacks and juvenile carp and rainbow trout

Paratenuisentis ambiguus is described from natural infections in adult eels and from laboratory infections in sticklebacks and juvenile carp and rainbow trout. In captured eels, female worms kept reproducing in the laboratory for at least 1 mo. In the 3 small laboratory hosts female worms did not release eggs and longevity did not exceed 3-30 days. It is concluded that the small fishes were unsuitable final hosts. Worm penetration into the intestinal wall of all hosts was shallow. Thus, the small fishes also proved to be unsuitable paratenic hosts. The worms ruptured the intestinal mucosa and the underlying tunica propria and they often seemed to change their sites of attachment. The proboscides carried an osmiophilic surface coat that seemed to be supported by liquid drops from necrotic host tissue and by osmiophilic material apparently discharged from pores in the worm's proboscis hooks. The coat contained lipids, polysaccharides, and/or proteoglycans and likely other substances. Around the hooks the proboscis tegument harbored conspicuous cisternae of rough endoplasmic reticulum as is typical for cells with secretory function. Mostly, the worms were found with semi-invaginated proboscides. The resulting cavity inside the proboscis seemed to collect lipids and other remnants of host cells from the lesions caused by the worms. Whether the apical hollow might function as a gastric cavity is discussed.     

A review of the Arhythmacanthidae (Acanthocephala) with a description of Heterosentis hirsutus n. sp. from Cnidoglanis macrocephala (Plotosidae) in Australia

Heterosentis hirsutus n. sp. is described from Cnidoglanis macrocephala (Siluriformes: Plotosidae) from the Swan Estuary, Western Australia. It is distinguished by having 14 longitudinal rows of 6-7 hooks per row on the proboscis, a trunk armed anteriorly and posteriorly (= genital spines) with minute spines and lemnisci that may extend to the posterior margin of the proboscis receptacle. The new species also has prominent fragmented nuclei in its trunk wall. New information is given for Heterosentis plotosi Yamaguti, 1935 from Plotosus lineatus (Siluriformes: Plotosidae) and H. paraplagusiarum (Nickol, 1972) Amin, 1985 from Paraplagusia guttata (Pleuronectiformes: Cynoglossidae), both from Queensland. A key to the species of Heterosentis Van Cleave, 1931 is provided. The Arhythmacanthidae subfamilies are reviewed: there is little utility in the recognition of these taxa because of the small number of genera involved and the validity of the characters on which they are based is in doubt, particularly whether trunk spines are present or absent. Only Acanthocephaloides Meyer, 1932, Breizacanthus Golvan, 1969, Euzetacanthus Golvan & Houin, 1964, Heterosentis, Hypoechinorhynchus Yamaguti, 1939 and Paracanthocephaloides Golvan, 1969 of the Arhythmacanthidae are considered valid. A key to these genera is provided. The monotypic genus Neoacanthocephaloides Cable & Quick, 1954 is considered a new synonym of Acanthocephaloides thus creating Acanthocephaloides spinicaudatus (Cable & Quick, 1954) n. comb. Arhythmacanthus Yamaguti, 1935 is maintained as a synonym of Heterosentis because the distinction between two and three hook types is made equivocal when the transition between the apical and subapical hooks is gradual.