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.     

Setal Structure and Chaetogenesis in Scolelepis squamata and Malacoceros fuliginosus (Spionidae,Annelida)

In Scolelepis squamata and Malacoceros fuliginosus two alternatingly arranged transverse rows of setae are found in each ramus. These are capillary setae in all thoracic setigers, whereas in abdominal setigers they may alternate with hooded hooks. In M. fuliginosus only the abdominal neuropodia bear hooded hooks, whereas in S. squamata these setae are present in both rami in the abdomen. Here every second seta (the capillary one) degenerates before its formation is complete, leading to a single row of hooded hooks. In the transverse rows new setae are formed in a medio-lateral formative site in both species. Additionally in each ramus there exists one longitudinal row of capillaries which each possesses its own formative site. Ultrastructure and formation of the hooded hooks in S. squamata is very similar to that of hooded hooks in Capitellidae. The hood is preformed by a certain group of microvilli of the chaetoblast, which soon differentiates two layers of microvilli, raising an inner and an outer hood lamella. The hooded hooks and their arrangement are regarded as homologous characters in Spionidae and Capitellidae. This indicates a closer relationship of Spionidae with a taxon consisting of Capitellidae, Arenicolidae, Maldanidae, Oweniida, Terebellida, Sabellida, and Pogonophora.     

<Emphasis Type="Italic">Atactorhynchus duranguensis</Emphasis> n. sp. (Acanthocephala: Atactorhynchinae) from <Emphasis Type="Italic">Cyprinodon meeki</Emphasis> (Pisces: Cyprinodontidae) near Durango,Mexico

Atactorhynchus duranguensisn. sp. (Acanthocephala: Atactorhynchinae) is described from the intestine of Cyprinodon meeki Miller, an endemic freshwater fish from a far-inland locality of Mexico. Diagnostic features include: body small, stout, ventrally curved; small cylindrical proboscis armed with 16 alternating vertical rows of four or five hooks; anterior two or three hooks conspicuous, stout and larger than other hooks, and have large, rod-shaped roots with a markedly and abruptly enlarged base; three posterior hooks of each row are smaller and rootless; single-walled proboscis receptacle; lemnisci equal in length, elongate and robust; and cement gland syncytial, larger than testis. The new species is smaller than A. verecundus Chandler, 1935, the only previously described species in the genus. The shape of the proboscis of the new species is strikingly different from that of A. verecundus, which is widest at the apex. Likewise, the greatest width of the trunk of the new species is in about the middle, differing from that of A. verecundus where the trunk is widest posteriorly. The new species also can be distinguished from A. verecundus because of its much smaller hook lengths and slightly smaller proboscis. In addition, the proportion of large apical proboscis hooks in relation to the small basal hooks is different: the basal hooks of A. verecundus are about half the size of the anterior hooks and but only about a quarter of the size in A. duranguensis. Unlike A. verecundus, the base of the roots are markedly and abruptly enlarged in the new species. Finally, the eggs of the new species are smaller (23–27 × 8–10 m) than those of A. verecundus (27–30 × 12–13 m).     

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.     

Grillotia australis n. sp. and G. pristiophori n. sp. (Cestoda: Trypanorhyncha) from Australian elasmobranch and teleost fishes

Two new species of Grillotia are described from elasmobranch and teleost fishes from south-eastern Australia. G. australis n. sp., from the Australian angel shark Squatina australis. Regan, most closely resembles G. smarisgora (Wagener, 1854) and G. angeli Dollfus, 1969, differing from both species in the presence of smaller bulbs, two or occasionally three hooks in each intercalary row in the basal region, reduced to one in the metabasal region compared with four or five hooks in the metabasal region of G. smarisgora and a single hook in G. angeli, and in the limited extent of the band of hooklets on the external surface in the basal region of the tentacle, a region which is covered with hooks in G. smarisgora. Plerocerci of this species were found in the mackerel Trachurus declivis (Jenys) (site not known) from Tasmania. G. pristiophori n. sp., from the saw sharks Pristiophorus cirratus (Latham) and P. nudipinnis Günther, most closely resembles G. spinosissima Dollfus, 1969 in possessing a scolex covered with spiniform microtriches, but differs in having six rather than five hooks in each principal row, no intercalary hooks and by possessing a band of hooklets on the external surface of the tentacle which diminishes distally into a single file, rather than persisting as a band eight to nine files wide. G. pristiophori is the first trypanorhynch to be recorded from saw-sharks.     

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.     

Seasonal variations of opisthaptoral hard parts of Gyrodactylus salaris Malmberg, 1957 (Monogenea: Gyrodactylidae) on parr of Atlantic salmon Salmo salar L. in the River Batnfjordselva,Norway

Seasonal variations in size and shape of the marginal hooks, the anchors and the ventral bar of the opisthaptor of Gyrodactylus salaris Malmberg, 1957 were studied. The G. salaris specimens were collected from parr of Atlantic salmon Salmo salar L. in the River Batnfjordselva, north-western Norway. Samples were taken at roughly monthly intervals during a two-year period. The marginal hooks, the anchors and the ventral bar showed considerable seasonal variation in size, but varied only slightly in shape. The variation in 12 of the 14 characters measured showed a significant regression to the variation in the water temperature. The total length of the marginal hooks of G. salaris can be considerably longer than the previously reported maximum of 40 m for the species.     

Changes in the curvature of sperm apical hooks in murine rodents

Sperm apical hooks in murine rodents play an important role in sperm competition. Apical hooks are more curved and longer in species with relatively larger testes, that is in species with a higher risk of sperm competition. The sperm can form aggregations, ‘trains’, that can move faster than individual sperm, thus reaching the egg earlier as was observed in Apodemus sylvaticus. The apical hook plays an important role for train formation. This study focuses on the changes in the curvature of sperm apical hooks during the final stages of spermiogenesis and stages before fertilization (sperm-life span). Apical hook curvatures of field mice (A. agrarius and A. sylvaticus) vary significantly between dormant and active sperm. In contrast, there are no significant differences among the stages in the eastern house mouse. Since there are high ranges of angle values in all stages, the mean angles of apical hook curvature are not appropriate for evaluating risk of sperm competiton. The ranges of angle values point to a level of flexibility of the apical hooks. The lengths of sperm hooks in individual species do not change during particular stages. The length and flexibility of the sperm apical hooks are important for the formation of sperm aggregations, thus these sperm characters indicate the risk of sperm competition and the sperm strategies in murine rodents.     

Chaetal arrangement and chaetogenesis of hooded hooks in Lumbrineris (Scoletoma) fragilis and Lumbrineris tetraura (Eunicida,Annelida)

As the structure and arrangement of chaetae are highly specific for annelid species and higher taxonomic entities, we assume that rather conservative information guarantees formation of specific chaetae. Each chaeta of an annelid is formed within an ectodermal invagination, and the modulation of the apical microvilli pattern of the basalmost cell of this invagination determines the structure of the chaeta. Any hypothesis of the homology of chaetae could thus be tested by examining the process of chaetal formation. Investigations into the ultrastructure and formation of hooded hooks in different capitellids and spionids revealed that these chaetae can be homologized. The hood of each of their hooded hooks is formed by elongation of two rings of microvilli peripheral to the chaetal anlage, which give rise to the inner and outer layers of the hood. The hood layers are well separated and surround an empty space. Superficially similar hooded hooks are described for certain Eunicida. Presently available cladistic analyses suggest that the hooded hooks of eunicidans evolved independently of those in Capitellidae and Spionidae. Compared with the latter two families, we therefore expected to find differences in chaetogenesis of the hooded hooks in the eunicids Lumbrineris (Scoletoma) fragilis and Lumbrineris tetraura (Lumbrineridae). This was the case. In these eunicidans, the hood was formed by the bisected apical wall of the chaetoblast right after the mid‐apical section of the chaeta had been sunk deeply into the chaetoblast during its formation. The apical wall generated a brush of microvilli that preformed the hood. Because the microvilli of the hood showed some accelerated differentiation, they soon merged with those of the slowly growing setal shaft to form the broad manubrium of the hooded hook in lumbrinerids. Our study confirms the predicted differences in chaetogenesis of the superficially similar hooded hooks of capitellids and spionids compared with those of eunicids.     

Seasonal variations of the opisthaptoral hard parts of Gyrodactylus derjavini Mikailov, 1975 (Monogenea: Gyrodactylidae) on brown trout Salmo trutta L. parr and Atlantic salmon S. salar L. parr in the River Sandvikselva,Norway

Seasonal variations in the size and shape of the marginal hooks, anchors and ventral bar of the opisthaptor of Gyrodactylus derjavini Mikailov, 1975 were studied. The G. derjavini specimens were collected from brown trout Salmo trutta L. parr and Atlantic salmon S. salar L. parr in the River Sandvikselva, southeastern Norway. Samples were taken at roughly monthly intervals during a 13-month period. The marginal hooks, anchors and ventral bars showed considerable seasonal variation in size, but varied very little in shape. The size increased when the water temperature decreased and vice versa.     

Three new genera of trypanorhynch cestodes from Australian elasmobranch fishes

Three new genera of trypanorhynch cestodes from Australian elasmobranch fishes collected in the Arafura Sea, off the Northern Territory, are described. Fossobothrium perplexum n. g., n. sp. (Otobothriidae), from the spiral valves of Anoxypristis cuspidata (Latham) and Pristis zijsron Bleeker, is similar to the otobothriid genera Pseudotobothrium Dollfus, 1942 and Poecilancistrium Dollfus, 1929 in possessing bothrial pits and a band of hooks on the tentacle, but differs from all known otobothriid genera in having the pits joined by a prominent velum. Iobothrium elegans n. g., n. sp. (Otobothriidae), from the spiral valve of Himantura jenkinsi (Annandale), is placed in the Otobothriidae because it possesses bothrial pits, but differs from Otobothrium Linton, 1890 and other genera in lacking intercalary hooks between the principal rows and in possessing a chainette on the external surface of the tentacle in the metabasal region. Oncomegoides celatus n. g., n. sp. (Eutetrarhynchidae), from the spiral valve of Dasyatis microps (Annandale) and Himantura jenkinsi, resembles Oncomegas Dollfus, 1929 in possessing two bothria and a megahook on the bothrial surface of the basal armature, but differs in possessing an extra row consisting of four intercalary hooks formed by the overlapping of two intercalary hooks on the external tentacular surface between each of the opposing principal rows and is therefore an atypical heteroacanth.     

Chimaerarhynchus n. g. andPatellobothrium n. g., two new genera of trypanorhynch cestodes with unique poeciloacanthous armatures,and a reorganisation of the poeciloacanthous trypanorhynch families

Chimaerarhynchus rougetae n. g., n. sp. is described fromSqualus acanthias andCentrophorus sp. from the coast of Senegal, and differs from all other trypanorhynch genera in having a chainette composed of dissimilar elements, that is, double-winged hooks alternating with pairs of hooks each with a single lateral wing. The new genus is allocated to the Gymnorhynchidae Dollfus, 1935.Patellobothrium quinquecatenatum n.g., n. sp. is described from the spiral intestine ofSphyrna mokarran from Darwin, Northern Territory, Australia and plerocerci fromRachycentron canadus from Queensland, Australia. The genus is distinguished from all others in possessing five chainettes. It is allocated to the family Mustelicolidae Dollfus, 1969. The relationships of all genera of trypanorhynchs possessing chainettes are discussed, and they are divided into three groups: (1) Dasyrhynchidae Dollfus, 1935, Lacistorhynchidae Guiart, 1927, Mustelicolidae and Hornelliellidae Yamaguti, 1954 are considered closely related since all genera possess two bothridia, a hermaphroditic duct and have hollow hooks; (2) Gymnorhynchidae, amended to contain onlyGymnorhynchus Rudolphi, 1819 andChimaerarhynchus n.g., is distinct in possessing four bothridia, an accessory seminal vesicle and hollow hooks; (3) Mixodigmatidae Dailey & Vogelbein, 1982, amended to includeMixodigma Dailey & Vogelbein, 1982 andHalysiorhynchus Pintner, 1913 has four bothridia, lacks seminal vesicles and a hermaphroditic duct and has solid hooks.A new family Molicolidae n. fam. is erected forMolicola Dollfus, 1935 andStragulorhynchus Beveridge & Campbell, 1988. The new family has a poeciloacanthous armature, and is distinguished by possessing a band of hooks on the external surface of the tentacle, four sessile bothridia and an acessory seminal vesicle.Myrmillorhynchus Bilqees, 1980 is suppressed as a synonym ofPterobothrium Diesing, 1850.Neogymnorhynchus Bilquees & Shah, 1982, is suppressed as a synonym ofPterobothrium, with the type species,N. platycephali becoming a synonym ofP. heteracanthum Diesing, 1850.Eulacistorhynchus Subhapradha, 1957 is considered agenus inquirendum;Gymnorhynchus cymbiumi Chincholikar & Shinde, 1977 is also a synonym ofPterobothrium heteracanthum Diesing, 1850.     

Structure of the zona pellucida and cumulus oophorus in three species of native Australian rodents

The sperm head of many Australian hydromyine rodents has three curved hooks projecting from its anterior margin; the structure of the hooks has been characterized, but their function is unknown. In this study, we have investigated whether the hooks might have evolved to assist sperm penetration through more formidable egg vestments, particularly the zona pellucida. Cumulus-oocyte complexes were obtained from two species that possess a three-hooked sperm head (Pseudomys australis and P. nanus) and one species that does not (Notomys alexis) and examined by light and electron microscopy. After fixation in the presence of ruthenium red, the zona pellucida was found to consist of a fibrillar meshwork, but there were no interspecific structural differences. A corona radiata was absent, and the cumulus extracellular matrix was composed of filaments and electron-dense granules in each species. Measurements of the zona thickness in freshly ovulated, unfixed oocytes revealed that it was thinnest (7.8 μm) in P. australis. Which has a three-hooked sperm head, and thickest (11.4 μm) in N. alexis, the species in which the ventral hooks are absent. Hence, no correlation was found between the thickness of the zona pellucida or the structure of the cumulus-oocyte complex, and the presence of three hooks on the sperm head. We conclude, therefore, that it is unlikely that the evolution of the three-hooked sperm head is an adaptation for penetration of increased barriers around the oocyte.     

Critical studies on the genus Callitetrarhynchus (Cestoda: Trypanorhyncha) with recognition of Rhynchobothrium speciosum Linton, 1897 as a valid species of the genus Callitetrarhynchus

Summary Callitetrarhynchus speciosus (Linton, 1897) n. comb. for Rhynchobothrium speciosum is redescribed from Pomatomus saltatrix and is compared with the only other species of the genus. C. gracilis (Rudolphi, 1819), also found in the same fish. The arrangement of hooks on the tentacle of both species is illustrated. The two species, which have been included under the name C. gracilis in the past, differ mainly in the oncotaxy, different shape of the hooks of the chainette, distinct distribution of frontal glands and in the different depth of the marginal bothidial groove. ac]19840904     

Gel filtration of particle-bound phytochrome

Pelletable phytochrome from hypocotyl hooks of Cucurbita pepo L. seedlings has been separated into two fractions by gel filtration on Sepharose CL-2B. One fraction with a K _av of 0.7 was detected only after red irradiation (in vivo or in vitro). This separated from a ribonucleoprotein fraction during gel filtration. The weak interaction with ribonucleo-protein which required magnesium (optimal at 10 mM) was overcome by high salt concentrations and prevented by ribonuclease treatment. The second phytochrome fraction was strongly associated with a high molecular weight material with a K _av of less than 0.1. Low levels of this complex were detected in extracts from dark grown tissue but were increased by red irradiation of excised hooks or crude extracts. The binding of phytochrome to the high molecular weight material did not require magnesium, was unaffected by ribonuclease treatment, and was much more resistant to high salt concentrations than was the phytochrome—ribonucleoprotein association. These results suggest that the association of phytochrome with this membrane—containing fraction is not electrostatic.The separation by agarose-gel filtration offers a useful technique for the preparation of membraneassociated phytochrome for physiological studies.Abbreviations EDTA ethylenediaminetetraacetic acid - P _r and P_fr phytochrome in the red and far-red absorbing forms - RNase ribonuclease - RNP ribonucleoprotein     

Raillietiella trachea n. sp., a pentastomid from the trachea of an oriental white-backed vulture Gyps bengalensis taken in Pakistan,with speculation about its life-cycle

A cephalobaenid pentastomid, Raillietiella trachea n. sp., from the trachea of a fledgling oriental white-backed vulture Gyps bengalensis taken in Punjab Province, Pakistan, is described. This is the first record of a pentastomid from a fully terrestrial bird. Overall, gross morphology was typical of Raillietiella Sambon, 1910 in most respects. However, the hooks of R. trachea were of equal size, whereas in other members of the genus anterior hooks are smaller than the posterior hooks. The diagnosis of R. trachea was made on the basis of four near-patent females, all of which contained relatively few eggs (c.570), all at the same stage of maturity. Comparison with the only other genus known to infect birds (two species of Reighardia Ward, 1899 from the air-sacs of marine birds) revealed striking parallels in this aspect of the functional anatomy of the female reproductive tract. As far as we know, this mode of egg-production is not found in other raillietiellids. Extrapolating primarily from the experimental life-cycle studies of Reighardia sternae (Diesing, 1864) Ward, 1899, we surmise that the life-cycle of R. trachea has to be direct and that parasite behaviour is an integral part of parasite transmission. The evidence suggests that transmission is from vulture-to-vulture, per os.     

A new genus and two new species of trypanorhynch cestodes (Tentaculariidae) from the sharks Carcharhinus sorrah (Müller & Henle) and Sphyrna lewini (Griffith & Smith) from off the coasts of Malaysia and Mexico

Two new tentaculariid species were found infecting carcharhiniform sharks from off the coasts of Malaysian Borneo and the southwestern coast of the Baja California Sur, Mexico. Both new species exhibit a homeoacanthous heteromorphous basal and a homeoacanthous homeomorphous metabasal armature. Since this hook arrangement is unique within the tentaculariids and the taxonomy in this group deeply depends on the tentacular armature, Reimeriella n. g. is erected to accommodate R. varioacantha n. sp. ex Carcharhinus sorrah (Müller & Henle) and R. mexicoensis n. sp. ex Sphyrna lewini (Griffith & Smith). Unlike R. mexicoensis n. sp., R. varioacantha n. sp. has a pars bothrialis not overlapping the pars bulbosa and the number of testes is higher. Reimeriella mexicoensis n. sp. possesses very large uncinate to falcate hooks in the basal armature, while in R. varioacantha n. sp. these hooks are almost the same in size as the remaining hooks in both the basal and metabasal armature. The latter species is the first tentaculariid species where the metabasal armature very closely resembles an eutetrarhynchid with a heteroacanthous typical homeomorphous metabasal armature and a high number of spiniform hooks per half spiral row (10–11 vs 6–7 in R. mexicoensis n. sp.) in the metabasal and apical armature. This pattern provides further morphological evidence for the close relationship of the Eutetrarhynchoidea and the Tentacularioidea. Reimeriella varioacantha n. sp. enriches the trypanorhynch fauna from off the coast of Malaysian Borneo while R. mexicoensis n. sp. is a novel record of a tentaculariid trypanorhynch from the Mexican Pacific.