Acanthocephalus reunionensis n sp (Acanthocephala: Echinorhynchidae), a parasite of Anguilla species (Anguillidae) from Reunion Island

In a survey of 118 eels Anguilla bicolor, A. marmorata and A. mossambica, (Anguillidae) indigenous to Reunion Island in the Mascarene island group, western Indian Ocean, a new species of acanthocephalan, Acanthocepholus reunionensis n. sp., was found. With a proboscis hook formula of 19 rows of 4-5 hooks, and elongated cement glands arranged in three pairs, this species differs from all other species in the genus. This is the first record of the genus Acanthocephalus occurring in eels from the African Region.     

Acanthocephalus saurius n. sp. (Acanthocephala: Echinorhynchidae) and other helminths from the lizard Norops limifrons (Sauria: Polychrotidae) from Costa Rica

Acanthocephalus saurius n. sp. from the small intestine of Norops limifrons collected in Costa Rica is described and illustrated. Acanthocephalus saurius n. sp. represents the third acanthocephalan species in which gravid individuals have been found in lizard hosts. In addition to A. saurius; 1 species of Trematoda, Mesocoelium monas; 3 species of Nematoda, Piratuba digiticauda, Strongyluris panamaensis, and Acuariidae gen. sp. (larvae in cysts) were found.     

Echinorhynchus brayi n. sp. (Acanthocephala: Echinorhynchidae) from Pachycara crassiceps (Roule) (Zoarcidae), a deep-sea fish

Echinorhynchus brayi n. sp. (Palaeacanthocephala: Echinorhynchidae) is described from Pachycara crassiceps (Roule) (Zoarcidae) from the Porcupine Seabight, Northeast Atlantic. The new species closely resembles E. canyonensis Huffman & Kliever, 1977, a parasite of a Pacific zoarcid, but has longer lemnisci, larger eggs and larger testes. E. brayi n. sp. can be readily differentiated from the ten other Echinorhynchus spp. recorded from deep-sea fishes (E. abyssicola, E. gadi, E. longiproboscis, E. malacocephali, E. melanoglaeae, E. muraenolepisi, E. petrotschenkoi, E. sebastolobi, E. trachyrinci and E. truttae), because it has fewer hooks per longitudinal row.     

Helminths from the giant mottled eel Anguilla marmorata Quoy & Gaimard in Japan,with a description of Acanthocephalus longiacanthus n. sp. (Acanthocephala: Echinorhynchidae)

Five helminths, including a new echinorhynchid acanthocephalan Acanthocephalus longiacanthus n. sp., are described based on specimens from the giant mottled eel Anguilla marmorata Quoy & Gaimard caught in a small river, western Japan. The new acanthocephalan is distinguished from the other congeners in terms of hook arrangement (8–9 longitudinal rows with 5–6 hooks per row) on proboscis, maximum length of hook blade (81–95 μm in male, 150–190 μm in female), lemnisci being longer than proboscis receptacle, and small-sized eggs (80–83 μm). Two monogeneans, Pseudodactylogyrus anguillae (Yin & Sproston, 1948) and P. bini (Kikuchi, 1929), and two acanthocephalans, Acanthocephalus gotoi Van Cleave, 1925 and Southwellina hispida (Van Cleave, 1925), were also found; this new material is described. The monogeneans are notorious as invasive parasites spreading worldwide via anthropogenic transportations of anguillid eels, but in Japanese waters A. marmorata appears to be an indigenous host for these parasites. Anguilla marmorata is a new host record for the acanthocephalans A. gotoi and S. hispida.     

Life history and population biology of adult Acanthocephalus lucii (Acanthocephala: Echinorhynchidae)

The life history and population biology of adult A. lucii in perch, Perca fluviatilis L., from the Forth and Clyde canal, Scotland, was investigated during May 1979-September 1981. There was an annual cycle in the size of the parasite population; prevalence and abundance (+/- SE) were highest during late spring and summer (70-90% and 14 +/- 4.3 to 16 +/- 5.6 worms/fish, respectively) but declined during late autumn and reached a minimum during winter (50-60% and 2.1 +/- 0.9 to 3.2 +/- 0.6 worms/fish). Parasite maturation was associated with higher water temperatures during spring and summer and most shelled acanthors were probably produced during summer and fall. There was only 1 generation of A. lucii per year, although generations tended to overlap and individuals within each generation did not develop synchronously. The sex ratio of adults was initially near unity but favoured females in the later stages of the infection. The distribution of A. lucii among perch was highly aggregated and stomach content analysis suggested that this was partly due to heterogeneity in perch feeding behaviour. The negative binomial and Poisson lognormal models fitted the data on worm distribution. Seasonal changes in the degree of parasite aggregation were detected, but no conclusive evidence of density-dependent controls on parasite population growth was obtained.     

Pilum pilum gen. et sp. n. (Acanthocephala: Echinorhynchidae) from freshwater fishes of the southeastern United States.

Pilum pilum gen. et sp. n. is described from the warmouth, Lepomis gulosus (Cuvier); brown bullhead, Ictalurus nebulosus (Lesueur); yellow bullhead, I. natalis (Lesueur); redbreast sunfish, L. auritus (Linnaeus); bluegill, L. macrochirus Rafinesque; spotted sunfish, L. punctatus (Valenciennes); and redfin pickerel, Esox americanus (Gmelin), from the Alabama River Drainage, brown bullhead from the Mobile Bay Drainage in Alabama, and pirate perch, Aphredoderus sayanus Gilliams, from an Atlantic Coast drainage in Georgia. The new genus most closely resembles the genus Acanthocephalus; it differs from this genus in having a distinctive pear-shaped proboscis, a long neck, and hooks which abruptly differ in size.     

Life history and population biology of larval Acanthocephalus lucii (Acanthocephala: Echinorhynchidae) in the isopod Asellus aquaticus

Hemocoels of 8,731 Asellus aquaticus collected from the Forth and Clyde canal in Glasgow, Scotland, from January 1980 to March 1981 were examined for larvae of Acanthocephalus lucii. Prevalence and mean intensity were generally low (1.5-8.3% and 1.0-1.6, respectively), but there was a slight seasonal infection pattern with fewer infected isopods during summer, reflecting the appearance of a new isopod generation. Although there were no distinct seasonal trends in the proportions of each larval stage, recruitment of larvae probably occurred mainly during summer and autumn. Some larvae reached the cystacanth stage by late summer or autumn; others overwintered as acanthors or acanthellae and completed development the following spring. The maximum life span of larvae was limited to 1 yr by annual turnover of the isopod population. The distribution of larval A. lucii among isopods was slightly aggregated. There was a peaked pattern in the relationship between isopod length and the prevalence, abundance, and degree of parasite aggregation. The rate of parasite development in laboratory-infected isopods was linearly related to temperature between 9 and 22 C; the temperature threshold was 5.7 C, and the larval parasite required 598 degree-days above threshold to complete development. Among laboratory-infected isopods, 2 mechanisms that could regulate the larval parasite population were detected: intraspecific competition and direct, parasite-induced isopod mortality. However, the intensity of infection in the natural habitat was consistently low and may have remained below the level at which these mechanisms operated.     

Acanthocephalus bufonis (Acanthocephala) from Bufo marinus (Bufonidae: Amphibia) in Hawaii.

During a survey of the helminth parasites of the introduced toad, Bufo marinus, on O'ahu, Hawaii, an acanthocephalan corresponding to Acanthocephalus bufonis (Shipley, 1903) was found in the intestinal tract. This is a new host and locality record for A. bufonis which has only previously been recorded from amphibians in the Orient. Possible mechanisms for the introduction of A. bufonis to Hawaii, and its transmission to the toad, are discussed. Almost 98% of toads were infected with a mean intensity of 28.6 acanthocephalans per infected toad. There was a significant negative correlation between host length and intensity of infection with subadult toads having significantly higher infection levels than adult male and female toads. Trunk length of both male and female acanthocephalans was significantly related to host length.     

Allopaternal care in the tessellated darter,Etheostoma olmstedi (Pisces: Percidae)

Synopsis Large male tessellated darters, Etheostoma olmstedi, defend flat-bottomed rocks, the undersides of which serve as spawning substrates. Because females attach eggs directly onto bare stone, a spawning bout necessarily decreases the surface area available for further breeding at a nest. In apparent response to the female preference of ovipositing on rocks with the most bare surface, fathers abandon nests with their attached offspring to search for rocks with more uncovered surface. Egg abandonment also results after roving fathers intercept and spawn with ripe females and remain at a different rock to care for a new clutch. In essence, large males appear to maximize the number of eggs they fertilize by sequentially monopolizing breeding patches that are temporarily most desirable to females. The costs to a father of abandoning his eggs appear to be low for two reasons: (1) non-territorial males, created by a scarcity of suitable rocks, readily occupy vacant nests, and clean and aerate the abandoned eggs; and (2) after water hardening, eggs are less vulnerable to cannibalism. The maintenance of eggs by nonparental males may be both incidental to scrubbing the ceiling for their own breeding and adaptive in that viable eggs stimulate females to spawn; neither would appear to involve parental investment costs. Thus, allopaternal care in the tessellated darter may have evolved because it is performed in the selfish pursuit of spawning opportunities while entailing little, if any, of the costs normally subsumed within parental investment.     

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.     

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.     

PERMANENT GENETIC RESOURCES: Microsatellite DNA primers for the candy darter, Etheostoma osburni and variegate darter, Etheostoma variatum, and cross-species amplification in other darters (Percidae)

In order to investigate a potential hybrid zone between the candy darter, Etheostoma osburni, and variegate darter, Etheostoma variatum, and examine population variation within E. osburni, a suite of primers for 15 polymorphic microsatellite loci were developed. The average number of alleles per locus was 5.5 in E. osburni and 7.6 in E. variatum, and the average observed heterozygosities were 62.5% and 71.4%, respectively. There were no deviations from Hardy-Weinberg equilibrium and no observed linkage disequilibrium after Bonferroni correction. The utility of these primers was also tested in 11 species of darters representing all four genera of darters. Success of cross-species amplification was largely consistent with phylogenetic relationships of darters.     

Life history of the gulf darter,Etheostoma swaini (Pisces: Percidae)

Synopsis Etheostoma swaini, the gulf darter, was collected from the Black Creek drainage in southern Mississippi (February 1978 – April 1979). The gulf darter generally inhabits small- to moderate-size creeks and occurs over a sand or sandy mud bottom, often in association with aquatic vegetation or a layer of organic debris. Larval dipterans were the most important food items, both numerically and volumetrically. Chironomids were found in 71–100% of the stomachs in all except the unusual March 16 collection. The length frequency distribution and the scale annuli analysis indicated there were three year-classes present in the population at any one time. Fifty-one percent of the specimens taken were less than 12 months old. During the mid-February to late March spawning season gulf darters were most often collected over clean gravel or gravelsand substrates. Laboratory observations suggest that the female burrows into the gravel where the demersal, adhesive eggs are deposited. Female gulf darters significantly outnumbered males at a ratio of 59:41.     

Microsatellite DNA markers for the rainbow darter,Etheostoma caeruleum (Percidae), and their potential utility for other darter species

The rainbow darter Etheostoma caeruleum is a small fish in the perch family (Percidae) that is adapted to fast‐flowing streams in eastern North America. It is relatively sensitive to habitat degradation and is widely used as a sentinel of stream condition. To provide a complementary tool for assessing the integrity of stream ecosystems, 16 highly polymorphic tetranucleotide microsatellite markers were identified for these darters. Between four and 16 loci were found to be useful in five congeneric species. These markers will be useful for characterizing population genetic structure and diversity of rainbow darters and related fishes.     

The nervous system in the praesoma of Echinorhynchus salmonis (Acanthocephala: Echinorhynchidae)

Based on light microscopic observations, nerve pathways are described for the first time in the praesoma of a species of the Echinorhynchidae. The pathways are described for 18 nerves, 8 paired and 2 single, which originate from the cerebral ganglion and a post-ganglionic cell and terminate in the body wall musculature and the proboscis. The location of two commissures formed by these nerves is also described.     

New genus, new species of Acanthocephala (Echinorhynchidae) from the Brazilian frog Hylodes phyllodes (Anura: Leptodactylidae)

Anuracanthorhynchus tritaxisentis n. gen., n. sp. from the intestines of the Brazilian frog Hylodes phyllodes (Leptodactylidae) is described and illustrated. Anuracanthorhynchus tritaxisentis n. gen., n. sp., is unique among the echinorhynchid Acanthocephala by possessing a spherical proboscis supporting a small number of hooks of equal size. It is the sixth acanthocephalan species reported from South American anurans.