Proboscis Hooks Research Articles

Resurrection of Pomphorhynchus tereticollis (Rudolphi, 1809) (Acanthocephala: Pomphorhynchidae) based on new morphological and molecular data

Abstract Pomphorhynchus tereticollis (Rudolphi, 1809) is here redescribed on the basis of Rudolphi’s material, deposited in the Museum für Naturkunde Berlin, and on acanthocephalans recently collected from the type host Platichthys flessus (L.) and the region embodying the type locality. Out of the paratypes of P. tereticollis, the lectotype and paralectotypes have been designated. Their morphology fits well with that of newly collected material of P. tereticollis dissected from the type fish host from the Baltic coast near Stralsund. The resurrection of P. tereticollis, previously considered a synonym of Pomphorhynchus laevis (Zoega in Müller, 1779), is supported by several morphological features distinguishing the two Pomphorhynchus species: 1. The basal parts of the proboscis hooks located on the posterior proboscis half possess proximal projections in P. tereticollis but not in P. laevis. This shape of the hook bases is clearly visible only in unfixed fresh worms; 2. The last hooks are situated at the anterior part of the bulbus or rarely at the posterior-most end of the proboscis in P. tereticollis, while they lie anterior to the end of the proboscis in P. laevis; 3. The proboscis hooks No. 5 or 6 are markedly stout (robust) and clearly distinct in comparison with the surrounding hooks in P. tereticollis, while less robust and more similar to the hooks in P. laevis. In addition, genetic divergence between P. tereticollis and P. laevis based on ITS1, ITS2 and COI sequencing supports the existence of two distinct species and reveals that some isolates previously identified as P. laevis were actually P. tereticollis. Previous and present morphological and genetic data show that both Pomphorhynchus species occur in freshwaters throughout Europe and may infect the same fish hosts, such as chub and barbel, and also several species of isopods (Gammaridae). This study also provides morphological evidence that Pomphorhynchus intermedius Engelbrecht, 1957 is a synonym of P. tereticollis, because the only discrimination character of the former species, the “existing but small proximal projections of basal parts of the proboscis hooks located on the posterior proboscis half” are present also in P. tereticollis.

On four species of echinorhynchid acanthocephalans from marine fish in Halong Bay, Vietnam, including the description of three new species and a key to the species of Gorgorhynchus

Four species of echinorhynchid acanthocephalans were collected from marine fish off Cat Ba Island, Halong Bay, Gulf of Tonkin, Vietnam, in the spring of 2009. Acanthocephalus halongensis n. sp. (Echinorhynchidae) from the redtail scad, Decapterus kurroides Bleeker 1855 (Carangidae), has a unique proboscis armature with a spiniform basal hook with lateral root and an incomplete receptacle wall posteriorly. Gorgorhynchus tonkinensis n. sp. (Rhadinorhynchidae) also from D. kurroides, has long, slender, winding lemnisci, many epidermal nuclei, and a narrow anterior trunk with a shoulder armed with 20 circles of tightly packed spines, the posterior four circles of which have abruptly larger spines than those in the anterior circles. Neorhadinorhynchus atypicalis n. sp. (Cavisomidae) from the rabbitfish, Siganus fuscescens (Houttuyn 1782) (Siganidae), has the largest number of proboscis hooks per row, testes wider than long, and four clustered cement glands. Micracanthorhynchica kuwaitensis Amin and Sey 1996 (Rhadinorhynchidae) from the spottail needlefish Strongylura strongylura (van Hasselt 1823) (Belonidae) was similar to specimens originally described from the Arabian Gulf off the Kuwaiti coast. These acanthocephalans were collected in small numbers but stood out as uniquely and considerably different from their closest relatives to warrant their reporting. All species of acanthocephalans and their host and geographic distribution are described, and a key to the species of Gorgorhynchus is provided.

First report of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) from marine fish of the eastern seaboard of Vietnam, with the description of six new species.

The occurrence of acanthocephalans of the genus Neoechinorhynchus Stiles and Hassall, 1905 in Vietnamese waters is reported for the first time. Six new species are described from seven species of marine fish of the families Belonidae, Clupeidae, Megalopidae, Mugilidae, and Sciaenidae, collected in Halong Bay of the eastern seaboard of Vietnam in 2008 and 2009. These are Neoechinorhynchus (Neoechinorhynchus) plaquensis n. sp. characterized by dermal plaques covering the entire trunk; Neoechinorhynchus manubriensis n. sp. with very long anterior proboscis hooks having roots with prominent anterior manubria and very small and equal middle and posterior hooks, two pseudoretractors in the receptacle, simple vagina, and terminal gonopore; Neoechinorhynchus pennahia n. sp. with equal anterior and middle proboscis and somewhat smaller posterior hooks, and terminal female gonopore; Neoechinorhynchus ampullata with many giant nuclei in the body wall and lemnisci and a parareceptacle structure complex which includes pumping ampullas reported for the first time; Neoechinorhynchus (Neoechinorhynchus) longinucleatus n. sp. with very long giant nuclei in the Lemnisci, anteriorly twisted vagina, and subterminal female gonopore. Neoechinorhynchus (Neoechinorhynchus) ascus n. sp. is the second species of Neoechinorhynchus found with the parareceptacle structure/ampulla complex. Neoechinorhynchus (Neoechinorhynchus) johnii Yamaguti, 1929 of Bilqees, 1972 is not N. johnii because of proboscis armature and other discrepancies with the Yamaguti material. Notes on host distribution and feeding habits are also included.

The morphology of an unique population of Corynosoma strumosum (Acanthocephala, Polymorphidae) from the Caspian seal, Pusa caspica, in the land-locked Caspian Sea using SEM, with special notes on histopathology

AbstractOver 700 specimens of Corynosoma strumosum (Rudolphi, 1802) Lühe, 1904 were collected from one young male Caspian seal, Pusa caspica (Gmelin) in the southern land-locked Caspian Sea in April, 2009. Collected worms showed consistent variations from those reported by other observers using light microscopy especially in proboscis hook and trunk spine patterns. SEM images revealed many features that have not been previously reported including the shape and distribution of trunk spines, dorsoventral differences in proboscis hooks and their organization, the baldness of anterior proboscis, the rough egg topography, epidermal micropores, and variations in the female gonopore. This isolated population of C. strumosum from the land-locked Caspian Sea is distinguished from others reported from open waters elsewhere by the distribution of trunk spines, consistently smaller size of trunk and testes, larger eggs, and fewer proboscis hooks. Histopathological sections reveal the invasive path of worms in host tissue with damage to intestinal villi and worm encapsulation. Information obtained from SEM studies and histopathological sections is reported for the first time.

Description of Heterosentis holospinus n. sp. (Acanthocephala: Arhythmacanthidae) from the Striped Eel Catfish, Plotosus lineatus, in Halong Bay, Vietnam, with a Key to Species of Heterosentis and Reconsideration of the Subfamilies of Arhythmacanthidae

Abstract Heterosentis holospinus n. sp. is 1 of 11 species of acanthocephalans collected from 13 species of marine fish in Halong Bay, Vietnam, in 2008 and 2009. The striped eel catfish, Plotosus lineatus (Thunberg, 1787), harbored a large number of individuals of the new species. Species of Heterosentis Van Cleave, 1931, are characterized by having 2 or 3 types of proboscis hooks in 10–14 rows, and trunk spines. Of the 15 known species of Heterosentis (including the new species), H. holospinus is distinguished by having a trunk entirely covered with spines and an anterior trunk cone free of spines. Only Heterosentis overstreeti Schmidt and Paperna, 1978, has a trunk that is also entirely covered with spines; it, however, differs from H. holospinus by lacking an anterior trunk cone but having 4 giant nucleated muscle cells in the anterior trunk, and 2 basal spines per proboscis hook row. Heterosentis holospinus has no such muscle cells, and the proboscis contains 3–4 spines per row. Only 2 other species o...

Histopathology of farmed freshwater fish infested with different helminthes

n this study, histopathology of tissues of different cultured fishes (Cyprinus carpio, Clarias gariepinus, Oreochromis aureus, Sarotherodon galilaeus and Tilapia zillii) due to different helminthes had been investigated. Obviously, the direct effect of helminth parasites mainly depend on their attachment organs. Herein, helminthes belong to monogenean, digenean, cestode, nematode and acanthocephalan parasites, were identified as Cichlidogyrus halli typicus, Dactylogyrus afrobarbae, Orientocreadium batrachoides, Polyonchobothrium clarias, Paracamallanus cyathopharynx, Procamallanus laevichonchus and Acanthosentis tilapiae respectively. Severe damage occurred to the gill tissue due to the monogeneans opithohaptor. Limited lesions to the infected tissue of the fish host due to the nematodes were induced at the attachment site by the parasite buccal capsule. Deep penetration of intestinal tissue of the fish infested with the cestode Polyonchobothrium clarias was occurred due to the parasitic scolex. The digenean Orientocreadium batrachoides induced damage by its sucker at the attachment site to the infected epithelia of the host tissue as well. The acanthocephalan parasite Acanthosentis tilapiae caused severe rupture of the infected tissue by its proboscis hooks at the attachment site. Moreover, it may lead to complete decompose to intestinal tissue of the host. It is worthy to conclude that, in cases of the intense infestation negative impact of the parasite become more dangerous.

Description of two new species of Rhadinorhynchus (Acanthocephala, Rhadinorhynchidae) from marine fish in Halong Bay, Vietnam, with a key to species

AbstractTwo rhadinorhynchid species of acanthocephalans, Rhadinorhynchus dorsoventrospinosus sp. nov. and Rhadinorhynchus laterospinosus sp. nov. are described from the redtail scad, Decapterus kurroides Bleeker, and the trigger fish Balistes sp., respectively. The hosts were collected off Cat Ba Island, Halong Bay, Gulf of Tonkin, Vietnam in May, 2009. This brings the total number of species of Rhadinorhynchus Lühe, 1911 to 38. Specimens of the first species are characterized by having 11–12 proboscis hook rows with 30–31 hooks each, large dorsal and ventral spines in the posterior field of trunk spines, large eggs (100 × 20), and subterminal gonopore in both males and females. It is further characterized by many prominent fragmented nuclei in the body wall. The 1 female of the second species has 18 proboscis hook rows with 24 hooks each, smaller eggs (62 × 17), lateral trunk spines connecting those in the anterior and the posterior fields, and subterminal female gonopore. Notes on the genus Rhadinorhynchus, lists of the invalid and valid species, and a key to species are provided. Raorhynchus Tripathi, 1959 is proposed to be a junior synonym of Rhadinorhynchus pending a revision of the species of Raorhynchus.

Helminth parasites from Red Sea fishes: Neowardula brayi gen. nov., sp. nov. (Trematoda: Mesometridae Poche, 1926) and Sclerocollum saudii sp. nov. (Acanthocephala: Cavisomidae Meyer, 1932)

Specimens of the fishes Acanthopagrus bifasciatus Forsskål (Sparidae) and Siganus rivulatus Forsskål (Siganidae) were caught in the Red Sea off the coast of Rabigh, Saudi Arabia. Four (25%) and 24 (80%) of these fishes, respectively, were found to harbour intestinal helminths. Acanthopagrus bifasciatus was parasitised by Neowardula brayi gen. nov., sp. nov. (Trematoda: Mesometridae) and S. rivulatus by Sclerocollum saudii sp. nov. (Acanthocephala: Cavisomidae). Neowardula brayi gen. nov. is similar to Wardula Poche, 1926, but clearly differs from it and from the other four genera of the family Mesometridae Poche, 1926 in having a ventral surface anterior to the intestinal bifurcation greatly modified into a well-developed, relatively deep pouch encircling the genital pore and constantly diagonal testes. Sclerocollum saudii sp. nov. is similar to S. rubrimaris Schmidt et Paprena, 1978 (type species), but clearly differs in having a proboscis only armed with 10 rows of hooks, smaller proboscis hooks, lemnisci much longer than proboscis receptacle and much smaller egg size. The developmental stages of this acanthocephalan (cystacanths, juveniles and immature worms) are also described and figured.

Proboscis profiler: a tool for detecting acanthocephalan morphotypes

Molecular studies conducted over the past 25 years have revealed previously unrecognised diversity in the phylum Acanthocephala. Several nominal species have been shown to represent complexes of morphologically cryptic biological species, a situation potentially confounding the analysis of ecological data. A software tool, 'Proboscis profiler', was developed to detect morphological heterogeneity in collections of superficially similar acanthocephalan worms based on the multivariate statistical analysis of proboscis hook dimensions. Proboscis profiler identifies objective, natural groups in a collection of acanthocephalans which may correspond to distinct biological species or populations. Initial trials demonstrate that Proboscis profiler can discriminate biological acanthocephalan species of the Echinorhynchus gadi Zoega in Müller, 1776 complex and differentiate between dorsal and ventral hook rows from the proboscis of E. salmonis Müller, 1784. Proboscis profiler is free software and can be downloaded from http://acanthocephala.sourceforge.net.

Redescription of Sphaerirostris picae (Acanthocephala: Centrorhynchidae) From Magpie, Pica pica, in Northern Iran, with Special Reference to Unusual Receptacle Structures and Notes on Histopathology

Adults of Sphaerirostris picae (Rudolphi, 1819) Golvan, 1956 are described from European magpie, Pica pica Linnaeus (Corvidae), collected in 2008 from wooded areas near the northern Iranian town of Tonekabon by the southern shores of the Caspian Sea. Other specimens also were collected from Corvus cornix Linnaeus, Corvus corone Linnaeus, and Corvus frugilegus Linnaeus (Corvidae) in the same location, as well as from some of these hosts in other locations. Our specimens had 31-38 proboscis hook rows on the ovoid anterior proboscis and 27-36 spine rows on the cylindrical- to cone-shaped posterior proboscis, each with 8-10 hooks and 2-5 spines per row, respectively. They are distinguished from those of all other species of the genus by having a unique prominent expansion of the dorsal inner receptacle wall, called the receptacle process (RP), anteriorly into the anterior proboscis and by the presence of longitudinal alveolar lobes throughout the receptacle and proboscis. The RP is described using histological sections. Sphaerirostris picae is further distinguished from 2 closely related species, namely, Sphaerirostris lancea (Westrumb, 1821) Golvan, 1956 and Sphaerirostris pinguis (Van Cleave, 1918) Golvan, 1956, by characteristics of proboscis armature, position of female gonopore, and other reproductive system and receptacle features. Histological sections revealed damage to host intestinal tissue.

Telosentis exiguus (von Linstow, 1901) (Palaeacanthocephala: Illiosentidae), a generalist parasite of fishes in the Mediterranean basin

The morphology of material of the acanthocephalan genus Telosentis van Cleave, 1923 from different parts of the Mediterranean basin is examined in order to assess the validity of T. molini van Cleave, 1923. A redescription of T. exiguus, a generalist species of fishes in the Mediterranean basin, is presented especially in relation to the number of proboscis hooks. The main characteristic of T. exiguus is a cylindrical or club-shaped proboscis, which is covered with 12 longitudinal rows of 14-19 hooks in males and 16-20 in females. Males and females differ in both body size and the number of proboscis hooks. T. molini is considered a junior synonym of T. exiguus. A key to the species of Telosentis is presented.

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Acanthocephala: Neoechinorhynchidae) from the freshwater fish Awaous banana (Valenciennes) (Gobiidae) in Mexico

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Eoacanthocephala: Neoechinorhynchidae) is described from the intestine of Awaous banana (Valenciennes) (Pisces: Gobiidae) collected in the Río Negro, a tributary in the upper Río Coatzacoalcos basin, Santa María Chimalapa, Oaxaca State, Mexico. It is the third species of Neoechinorhynchus Stiles & Hassall, 1905 described from Mexican freshwater fishes, although 36 other species are known from freshwater fishes in the Americas. Like four other species of Neoechinorhynchus from freshwater fishes in North America and Mexico, N. (N.) limi Muzzall & Buckner, 1982, (N.) rutili (Müller, 1780) Stiles & Hassall, 1905, N. (N.) salmonis Ching, 1984 and N. (N.) roseus Salgado-Maldonado, 1978, males and females of the new species are less than 20 mm in length, lack conspicuous sexual dimorphism in size, have a small proboscis of about 0.1 mm in length with the largest hooks being the anteriormost, about 30-90 microm in length and of equal size, and have subequal lemnisci, larger than the proboscis receptacle but still relatively short and, in males, generally restricted to a position considerably anterior to the testes. The new species is closest to N. (N.) roseus, but it is distinguished from it by having: (1) a slightly larger cylindrical proboscis with almost parallel sides versus a globular proboscis with a rounded tip which is shorter and somewhat wider in N. (N.) roseus; (2) smaller but robust anterior proboscis hooks that do not reach the equatorial level or extend beyond the hooks of the middle circle as in N. (N.) roseus; and (3) the female gonopore situated ventrally subterminal, as opposed to being a significant distance anteriorly to the posterior extremity in N. (N.) roseus.

Extraintestinal Migration of Centrorhynchus sp. (Acanthocephala: Centrorhynchidae) in Experimentally Infected Rats

Reptiles were known to serve as paratenic hosts for Centrorhynchus (Acanthocephala: Centrorhynchidae) in Korea, but the infection course in experimental animals was not elucidated yet. In this study, the tiger keelback snakes (Rhabdophis tigrinus) were collected and digested with artificial pepsin solution, and the larvae of Centrorhynchus were recovered from them. Then, the collected larvae were orally infected to rats for developmental observations. In rats, all the larvae were observed outside the intestine on day 3 post-infection (PI), including the mesentery and abdominal muscles. As for the development in rats, the ovary of Centrorhynchus sp. was observed at day 15 PI, and the cement glands were 3 in number. Based on the morphological characteristics, including the arrangement of proboscis hooks, these larvae proved to be a species of Centrorhynchus, and more studies were needed for species identification.

Acanthocephala from Amphibians in China with the Description of a New Species of Pseudoacanthocephalus (Echinorhynchida)

Amphibians of 24 species were surveyed for acanthocephalans in 4 nature reserves in 2 Chinese provinces during 2004–2006. Pseudoacanthocephalus bufonis (Echinorhynchida) occurred in both nature reserves in Guangxi Province. In the Jing Xi County Provincial Nature Reserve, P. bufonis infected 36 of 62 amphibians at a mean intensity of 9.9. Less than 250 km away, at Shiwandashan National Nature Reserve, 5 of 20 amphibians were infected at a mean intensity of 6.2. Pseudoacanthocephalus bufonis was not found in either of the reserves in Guizhou Province. In the Kuan Kuoshui Nature Reserve, 9 of 28 amphibians were parasitized at a mean intensity of 2.0 by a previously undescribed species of Pseudoacanthocephalus , and no acanthocephalan occurred in a small sample of 2 toads at Dashahe Nature Reserve. The new species, Pseudoacanthocephalus reesei n. sp., differs from all others in the genus by typically having 14 longitudinal rows of 4 hooks, each of which is much longer than corresponding hooks of any other species of the genus. The length of proboscis hooks increases from the apex to the base of the proboscis, further distinguishing the new species from all but Pseudoacanthocephalus nguyenthileae .

Redescription of Rhadinorhynchus ornatus (Acanthocephala: Rhadinorhynchidae) from Skipjack Tuna, Katsuwonus pelamis, Collected in the Pacific Ocean off South America, with Special Reference to New Morphological Features

Adults of Rhadinorhynchus ornatus Van Cleave, 1918 were collected from the small intestine of skipjack tuna, Katsuwonus pelamis (Linnaeus), in the high seas of the Pacific Ocean off the west coast of South America (new parasite locality record) and described using optical microscopy and a scanning electron microscope (SEM). Our specimens were somewhat comparable to those described from North America and Japan, but had more trunk spines. Definitive differences between the length and thickness of each of the dorsal and ventral proboscis hooks are noted for the first time, with most ventral middle hooks being relatively shorter and more robust than dorsal middle hooks. The SEM documented, for the first time, the different surface topography of the tegument in the proboscis, the neck, and in 3 trunk regions; the presence of microtrichs in the mid- and posterior trunk regions; the elevated base of trunk spines; the circular arrangement of basal proboscis hooks; the different morphology of all dorsal and ventral proboscis hooks and the striations of their surface; the ribbed surface topography of eggs; the elevated slit-like female gonopore; and the rimmed edge of the bursa. The presence of microtrichs on the tegumental surface is further supported by transmission electron microscopy studies. This is the first report of microtrichs in any species of Acanthocephala and the second report of striations in proboscis hooks. The geographical distribution of R. ornatus appears to correspond, at least in part, to that of its epipelagic primary host, K. pelamis, throughout the world in waters ranging in temperature from 14.7 to 30 C.

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.

Description and morphological variability of Neoechinorhynchus beringianus 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.

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.

New and Already Known Acanthocephalans Mostly from Mammals in Vietnam, with Descriptions of Two New Genera and Species in Archiacanthocephala

Adults of 2 new species and 2 new genera of acanthocephalans in class Archiacanthocephala, collected between 1998 and 2004 in Vietnam from the intestines of mammals, are described, i.e., Cucullanorhynchus constrictruncatus n. gen., n. sp. (Oligacanthorhynchidae) from a leopard Panthera pardus (Linnaeus) (Mammalia: Felidae) and Paraprosthenorchis ornatus n. gen. n. sp. (Oligacanthorhynchidae) from the Chinese pangolin Manis pentadactyla (Linnaeus) (Mammalia: Manidae). Adult Sphaerechinorhynchus macropisthospinus Amin, Wongsawad, Marayong, Saehoong, Suwattanacoupt, and Sey, 1998 (Plagiorhynchidae) are described for the first time from 2 females collected from a tiger Panthera tigris (Linnaeus) (Mammalia: Felidae) and from 1 male from a water monitor Varanus salvator Laurenti (Reptilia: Varanidae). Characteristic features distinguishing the new species or genera from related taxa are as follows. The trunk of C. constrictruncatus has an anterior hood in both sexes and a posterior constriction in females. The anterior trunk of P. ornatus has many small festoons and proboscis hooks are inserted in elevated papillae separated by beady, near hexagonal, ornate grids.

New and Already Known Acanthocephalans from Amphibians and Reptiles in Vietnam, with Keys to Species of Pseudoacanthocephalus Petrochenko, 1956 (Echinorhynchidae) and Sphaerechinorhynchus Johnston and Deland, 1929 (Plagiorhynchidae)

Adults of 2 new species in 2 orders of acanthocephalans obtained from the intestines of terrestrial amphibians and reptiles collected between 1998 and 2004 in Vietnam are described here. Pseudoacanthocephalus nguyenthileae n. sp. (Palaeacnthocephala: Echinorhynchidae) was collected from 5 species of terrestrial amphibians: (1) the common Sunda toad Bufo melanostictus Schneider (Bufonidae); (2) Paa verucospinosa (Bourret); (3) Gunther's Amoy frog Rana guentheri Boulenger; (4) Taipei frog R. taipehensis Denburgh (Ranidae), and (5) the Burmese whipping frog Polypedates mutus (Smith) (Racophoridae); as well as from the Chinese cobra Naja atra Cantor (Reptilia: Elapidae) and house gecko Hemidactylus frenatus Dumeril and Bibron (Reptilia: Gekkonidae). Sphaerechinorhynchus maximesospinus n. sp. (Plagiorhynchidae: Sphaerechinorhynchinae) was isolated from a king cobra Ophiophagus hannah (cantor) (Reptilia: Elapidae). Cystacanths of Porrorchis houdemeri (Joyeux and Baer, 1935) Schmidt and Kuntz, 1967 (Plagiorhynchidae: Porrorchinae) obtained from the mesenteries of banded krait Bungarus fasciatus (Schneider) (Reptilia: Elapidae), a paratenic host, are reported for the first time. Keys to the species of Pseudoacanthocephalus and Sphaerechinorhynchus are included. Characteristic features distinguishing the new species from related taxa include: P. nguyenthileae has 15-19 (usually 16-18) proboscis hook rows, each with 5-6 hooks that progressively increase in length and size posteriorly. The largest, intermediate, and smallest proboscis hooks of S. maximesospinus are the middle, anterior, and posterior hooks, respectively; the proboscis and neck are enclosed in a membrane. Morphometric characteristics of P. nguyenthileae show host-related variability.