A new species of Pomphorhynchus (Acanthocephala: Palaeacanthocephala) in freshwater fishes from central Chile

This study describes a new species of Pomphorhynchus collected from Percilia gillissi Girard, 1855 from the Za?artu canal, between the sister basins of the Itata and Laja rivers, in central Chile. Pomphorhynchus moyanoi n. sp. is characterized by an asymmetrical, well-differentiated subspherical bulb and 12-14 longitudinal rows of 13-14 hooks; the third and the fourth hook in each row are stout. Among South American species, P. moyanoi n. sp. shows some similarities to the Chilean species P. yamagutii Schmidt & Hugghins, 1973, but it differs in having a longer neck, larger bulb, and different proboscis armature arrangement. Pomphorhynchus moyanoi n. sp. differs from P. patagonicus Ortubay, Ubeda, Semenas & Kennedy 1991, in the bulb shape (protuberances), number of rows, fourth hook size and basal hook size. Pomphorhynchus moyanoi n. sp. also differs from P. sphaericus in the arrangement of hooks (number of rows and hooks per row), length and width of the proboscis, neck width, and symmetry of the bulb.     

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.     

Comparison of morphological characters in Irish and English populations of the acanthocephalan Pomphorhynchus laevis (Müller, 1776)

Pomphorhynchus laevis is believed on ecological evidence to exist as three strains in the British Isles. However, the strains have never been shown to be capable of being distinguished using morphological characters. A morphological comparison was made between a sample of P. laevis from Salmo trutta in L. Feeagh in the west of Ireland and a sample from Leuciscus cephalus in R. Culm in the south of England. The length and width of the trunk, neck, bulb, proboscis and hooks were measured. The number of hooks per row, the number of rows and the positions of the stoutest and longest hooks were also recorded. A Principal Components Analysis based on the morphological measurements confirmed the separation of the two populations and showed that two characters successfully identified the populations: the position of the stoutest hook and the ratio of numbers of anterior to posterior hooks.     

Description and host relationships of Polymorphus spindlatus n. sp. (Acanthocephala: Polymorphidae) from the heron Nycticorax nycticorax in Peru

Polymorphus spindlatus n. sp. is described from the black-crowned night heron, Nycticorax nycticorax, in Lake Titicaca, Peru. It is distinguished from all 27 known species of the subgenus Polymorphus by its spindle-shaped proboscis and its trunk shape, the anterior 2/3 of which is ovoid, tapering into a tubular posterior end. It resembles Polymorphus brevis (=Arhythmorhynchus brevis), which is, however, longer and considerably more slender, and has smaller and more numerous proboscis hooks per row and smaller eggs. It is separated also from Polymorphus swartzi, Polymorphus striatus, Polymorphus contortus, and Polymorphus cincli by its proboscis armature (usually 18 longitudinal rows of 11-13 hooks each), among other characters. Histopathological sections of host tissue show well defined localized damage including hemorrhaging with subsequent phagocyte cell migration (granular tissue). The lumen of the host intestine is obstructed and villi show compression. The proboscis of P. spindlatus extends through the intestinal mucosa and submucosa, displacing the smooth muscle layers of the muscularis externa. Fibrosis also was observed.     

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.     

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.     

Morphological and molecular data for a new species of <Emphasis Type="Italic">Pomphorhynchus</Emphasis> Monticelli, 1905 (Acanthocephala: Pomphorhynchidae) in the Mexican redhorse <Emphasis Type="Italic">Moxostoma austrinum</Emphasis> Bean (Cypriniformes: Catostomidae) in central Mexico

Pomphorhynchus purhepechus n. sp. is described from the intestine of the Mexican redhorse Moxostoma austrinum Bean (Catostomidae) in central Mexico. The new species can be distinguished from the other seven described species of Pomphorhynchus Monticelli, 1905 in the Americas by a subspherical proboscis and 14 longitudinal rows with 16–18 hooks each; the third and the fourth row of hooks are alternately longest. Sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and the large subunit (LSU) rDNA (including the domains D2-D3) were used to corroborate the morphological distinction between the new species and Pomphorhynchus bulbocolli Linkins in Van Cleave, 1919, a species widely distributed in several freshwater fish species across Canada, USA, and Mexico. The genetic divergence estimated between the new species and the isolates of P. bulbocolli ranged between 13 and 14% for cox1, and between 0.6 and 0.8% for LSU. Maximum likelihood and Bayesian inference analyses of each dataset showed that the isolates of P. bulbocolli parasitising freshwater fishes from three families, the Catostomidae, Cyprinidae and Centrarchidae, represent a separate lineage, and that the acanthocephalans collected from two localities in central Mexico comprise an independent lineage. In addition, our analysis of the genetic variation of P. bulbocolli demonstrates that individuals of this acanthocephalan from different host species are conspecific. Finally, the distribution, host-association, and phylogenetic relationship of the new species, when placed in the context of the region’s geological history, suggest that both host and parasite underwent speciation after their ancestors became isolated in Central Mexico.     

Two new species of Moniliformis (Acanthocephala: Moniliformidae) from Malaysia

Moniliformis tarsii n. sp. was found in Tarsius bancanus. It is unique in possessing 11-12 longitudinal rows of 6-7 hooks each. Hooks 2 and 3 are conspicuously enlarged, 41-55 microns long. Moniliformis echinosorexi n. sp. differs from all other species in having 12-15 rows of 11-13 hooks that are 34-36 microns long, and in having a proboscis receptacle 1.2-2.0 mm long. Several new host records for M. moniliformis are presented.     

A new Acanthocephala Breizacanthus ligur sp. n. (Palaeacanthocephala: Arhythmacanthidae Yamatugi, 1935) parasite of some species of benthic fishes from the Ligurian Sea]

Breizacanthus ligur sp.n. is described and figured from several benthic fishes from the Ligurian Sea. The host species are: Argentina sphyraena, Chlorophthalmus agassizi, Gadiculus argenteus, Phycis blennoides, Coelorhynchus coelorhynchus, Capros aper, Callionymus phaeton, Helicolenus dactylopterus. The parasites were considered as belonging to the family Arhythmacanthidae Yamaguti, 1935 and to the genus Breizancanthus Golvan, 1969. Breizancanthus ligur differs from the only two known species of the genus B. irenae and B. chabaudi for the number of longitudinal rows of hooks and-or numbers of hooks in each longitudinal row, arrangment of cement glands, length of body and lenght of male genital apparatus ratio, lenght of female genital apparatus and shape of embroyophore.     

Durettechina beveridgei n. g., n. sp. (Nematoda: Seuratidae) from Antechinus spp. (Dasyuridae: Marsupialia) from Australia

Durettechina beveridgei n. g., n. sp. (Nematoda: Seuratidae) is described from Antechinus flavipes (Dasyuridae) from Victoria and New South Wales. A single female from A. bellus from the Northern Territory may also be D. beveridgei. This new genus is compared with other genera of the Echinonematinae, to which it has been assigned. The genus has a unique body armature and most closely resembles Chabaudechina, in the armature of the cephalic bulb, but has four rather than five rows of hooks, and Linstowinema, in having body hooks on the cuticle of the anterior region, but has 18–22 hooks in each row rather than 14–16. The hooks of Durettechina are also smaller and have a less complex root morphology than those of Linstowinema. Durettechina resembles Seurechina and Chabaudechina in having caudal alae into which papillae extend, but differs from both these genera in the number and arrangement of the caudal papillae, as well as in the body armature. Durettechina, is most different from Bainechina, which has neither hooks on a cephalic bulb nor body hooks on the anterior region nor caudal alae.     

A new acanthocephalan family, the Isthmosacanthidae (Acanthocephala: Echinorhynchida), with the description of Isthmosacanthus fitzroyensis n. g., n. sp. from threadfin fishes (Polynemidae) of northern Australia

Isthmosacanthus fitzroyensis n. g., n. sp. is described from two species of protandrous fish, Eleutheronema tetradactylum (Shaw) and Polydactylus macrochir (Günther), from the waters around the coast of northern Australian. The new species can be distinguished from all others by the following combination of characters: proboscis shape and armature (22 rows of 13-14 hooks), short neck, trunk spined anteriorly and having two swellings (one bulbous) with a narrow isthmus in between, long tubular lemnisci and six tubular cement glands. Although I. fitzroyensis has been confused with a species of Pomphorhynchus Monticelli, 1905 in the literature, it can be distinguished from all pomphorhynchids, including species of Longicollum Yamaguti, 1935 and Pyriproboscis Amin, Abdullah & Mhaisen, 2003, by the suite of characters listed above. The placement of the species of Pyriproboscis in the Pomphorhynchidae Yamaguti, 1939 is problematical, because it has a short neck, two distinct hook types comprising the proboscis armature and only two rather than six cement glands. A new family, the Isthmosacanthidae n. fam., is erected to contain Isthmosacanthus together with Gorgorhynchoides Cable & Linderoth, 1963 and Golvanorhynchus Noronha, Fabio & Pinto, 1978, genera having an elongate to clavate proboscis, anterior trunk spines, elongate lemnisci, and six tubular cement glands. The validity of this determination, based on the importance of cement gland number and phylogenetic analysis, is argued.     

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.     

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.     

New species of thorny-headed worms of the genus Echinorhynchus (Echinorhynchidae) from fish of the southwestern Atlantic

Two new species of Acanthocephala of the genus Echinorhynchus were found and described from fishes of Falkland-Patagonia and South Georgia Island area. E. longiproboscis sp. n. from Dissostichus eleginoides and Macrourus holotrachys intestines differs from its close relative E. gadi (Zoega in Müller, 1776) in proboscis armature and the proboscis to the body length ratio. E. georgianus sp. n. from D. eleginoides intestines differs from E. gadi in proboscis armature and length and shape of the basal hooks.     

Histopathology in Leuciscus cephalus (Pisces: Cyprinidae) resulting from infection with Pomphorhynchus laevis (Acanthocephala).

The histopathology present in Leuciscus cephalus Risso 1826 from the River Po, naturally infected with the acanthocephalan Pomphorhynchus laevis Müller 1776, was studied and described. The parasite was only found within the host's digestive tract, and a density of 10 P. laevis per square centimeter was common. On histological examination it was noticed that both male and female parasites penetrated deeply through all the layers of the host digestive tract by means of their slender neck, bulb and proboscis; thus the bulb and proboscis become encapsulated beneath the serosa and mesentery. As a result, the presence of a capsule was noticed on the external surface of the host digestive tract. P. laevis caused local damage to the intestinal wall, and the parasite elicited an intense host reaction. The response of L. cephalus at the attachment site of the acanthocephalan was hyperplasia of host connective tissue, with cellular infiltration. In a few hosts, the presence of a fibrous nodule on the outer surface of the alimentary canal was observed.     

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.