A new species of Aponurus Looss, 1907 (Digenea: Lecithasteridae) in butterflyfishes (Perciformes: Chaetodontidae) from New Caledonia

Aponurus chelebesoi n. sp. is described from Chaetodon auriga, C. citrinellus, C. ephippium, C. flavirostris, C. lineolatus, C. melannotus, C. mertensii, C. pelewensis, C. lunulatus, C. vagabundus, Coradion altivelis, Forcipiger flavissimus, Heniochus acuminatus, H. chrysostomus and H. monoceros from the southern coast of New Caledonia. It is distinguished from most species in the genera Aponurus (synonym Brachadena) and Lecithophyllum by its claviform (as opposed to oval to subglobular) vitelline lobes. Three species, A. pyriformis, Lecithophyllum vogeae and Brachadena cheilonis, have similar claviform vitelline lobes, but differ from A. chelebesoi in their tandem testes and the distinct egg-size.     

Redescriptions of two frequently recorded but poorly known hemiurid digeneans, Lecithochirium musculus (Looss, 1907) (Lecithochiriinae) and Ectenurus lepidus Looss, 1907 (Dinurinae), based on material from the western Mediterranean

Two frequently reported but poorly known hemiurid digeneans, Lecithochirium musculus (Looss, 1907) (Lecithochiriinae), from the stomach of Trachinus draco and Citharus linguatula, and Ectenurus lepidus Looss, 1907 (Dinurinae), from the stomach of Spicara maena, are redescribed based on material from off the Barcelona coast of the western Mediterranean. The two species are commented upon, and Lecithochirium israelense Fischthal, 1980 is considered a synonym of L. musculus. Records of the two species in the Mediterranean Basin and North East Atlantic region are summarised.     

The Lepocreadiidae (Digenea) of fishes of the north-east Atlantic: review of the genera Opechona Looss, 1907 and Prodistomum Linton, 1910

The genera Opechona Looss and Prodistomum Linton are redefined: the latter is re-established, its diagnostic character being the lack of a uroproct. Pharyngora Lebour and Neopechona Stunkard are considered synonyms of Opechona, and Acanthocolpoides Travassos, Freitas & Bührnheim is considered a synonym of Prodistomum. Opechona bacillaris (Molin) and Prodistomum [originally Distomum] polonii (Molin) n. comb. are described from the NE Atlantic Ocean. Separate revisions with keys to Opechona, Prodistomum and ‘Opechona-like’ species incertae sedis are presented. Opechona is considered to contain: O. bacillaris (type-species), O. alaskensis Ward & Fillingham, O. [originally Neopechona] cablei (Stunkard) n. comb., O. chloroscombri Nahhas & Cable, O. occidentalis Montgomery, O. parvasoma Ching sp. inq., O. pharyngodactyla Manter, O. [originally Distomum] pyriforme (Linton) n. comb. and O. sebastodis (Yamaguti). Prodistomum includes: P. gracile Linton (type-species), P. [originally Opechona] girellae (Yamaguti) n. comb., P. [originally Opechona] hynnodi (Yamaguti) n. comb., P. [originally Opechona] menidiae (Manter) n. comb., P. [originally Pharyngora] orientalis (Layman) n. comb., P. polonii and P. [originally Opechona] waltairensis (Madhavi) n. comb. Some species are considered ‘Opechona-like’ species incertae sedis: O. formiae Oshmarin, O. siddiqii Ahmad, 1986 nec 1984, O. mohsini Ahmad, O. magnatestis Gaevskaya & Kovaleva, O. vinodae Ahmad, O. travassosi Ahmad, ‘Lepidapedon’ nelsoni Gupta & Mehrotra and O. siddiqi Ahmad, 1984 nec 1986. The related genera Cephalolepidapedon Yamaguti and Clavogalea Bray and the synonymies of their constituent species are discussed, and further comments are made on related genera and misplaced species. The new combination Clavogalea [originally Stephanostomum] trachinoti (Fischthal & Thomas) is made. The taxonomy, life-history, host-specificity and zoogeography of the genera are briefly discussed.     

A review of the genus Parahemiurus Vaz & Pereira, 1930 (Digenea: Hemiuridae)

The genus Parahemiurus Vaz & Pereira, 1930 (syn.: Daniella Sahai & Srivastava, 1977) is defined, its major morphological characters discussed and a key to species given. The species P. merus (Linton, 1910) (syns: P. parahemiurus Vaz & Pereira, 1930, P. sardiniae Yamaguti, 1934, P. seriolae Yamaguti, 1934, P. platichthyi Lloyd, 1938, P. atherinae Yamaguti, 1938, P. harengulae Yamaguti, 1938, P. noblei King, 1962) and P. anchoviae Pereira & Vaz, 1930 are described. Other species recognized are P. clupeae Yamaguti, 1953, P. [originally Daniella] madrasensis (Sahai & Srivastava, 1977) n. comb. (syns: P. dussumieriai Hafeezullah, 1981, P. indicus Ahmad, 1981), P. ecuadori Manter, 1940, P. engraulisi Gupta & Jahan, 1977 (syns: P. cameroni Gupta & Ahmad, 1977, P. puriensis Ahmad, 1981, P. simhai Gupta & Gupta, 1978, P. tricanthusi Gupta & Puri, 1984) and P. yanamense Hafeezullah, 1980. Forms considered species inquirendae are P. arripidis Lebedev, 1971, P. clupeae of King (1964), P. dogieli Skrjabin & Guschanskaya, 1953, P. pseudosciaenae Shen, 1985 and P. trachichthodi Lebedev, 1968. Host and locality information is given in detail for all species. The complete life-cycle is not known, but metacercariae are reported in chaetognaths and teleosts. The definitive hosts of Parahemiurus spp. most frequently reported belong in the families Clupeidae and Carangidae and the genus is most commonly reported in temperate and subtropical waters.     

First steps to restructuring the problematic genus Lasiotocus Looss, 1907 (Digenea: Monorchiidae) with the proposal of four new genera

Lasiotocus Looss, 1907 is the largest genus within the Monorchiidae Odhner, 1911, with 52 species currently considered valid. Species belonging to this genus exhibit wide morphological variation and it is likely that many of them belong in other genera; however, testing the validity of the group has been hampered by a lack of molecular sequence data, especially for the type-species. Here, we report the first DNA sequences for Lasiotocus mulli (Stossich, 1883) Odhner, 1911, the type-species of the genus, and only the sixth Lasiotocus species to be sequenced. Sequences were generated for three ribosomal DNA markers, the ITS2, 18S and 28S regions, and for one mitochondrial DNA marker, the cox1 region. Phylogenetic analyses show that the six sequenced species form four clearly distinct clades, each of which we argue require separate genera. On the basis of these relationships and review of the morphology of all species in the genus, we propose a system of six genera. Four genera, Lasiotocus, the resurrected concept of Ancylocoelium Nicoll, 1912, Infundiburictus n. gen., and Sinistroporomonorchis n. gen., represent the four molecular clades. Two genera, Paralasiotocus n. gen. and Alloinfundiburictus n. gen., are proposed on the basis of morphology only. Ancylocoelium is resurrected for Ancylocoelium typicum Nicoll, 1912, Infundiburictus is erected for Lasiotocus arrhichostoma Searle, Cutmore & Cribb, 2014, Sinistroporomonorchis is erected for Lasiotocus glebulentus Overstreet, 1971and Lasiotocus lizae Liu, 2002, Paralasiotocus is erected for Lasiotocus okinawaensis Machida, 2011, and Alloinfundiburictus is erected for Lasiotocus cacuminatus Nicoll, 1915. Of the 52 species presently recognised in Lasiotocus, 43 are distributed among these genera; nine are considered species inquirendae or are transferred to other genera. We think it likely that more genera will be required for the species reviewed here but more sequence data are essential to further refine the classification.     

On the morphology of Acanthostomum spiniceps (Looss, 1896) and A. absconditum (Looss, 1901) (Digenea: Cryptogonimidae: Acanthostominae) with particular reference to the juvenile stage

The morphology of juvenile and adult stages of Acanthostomum spiniceps and A. absconditum, from bagrid fish of the river Nile in Egypt, was studied with both light and scanning electron microscopy. In early juveniles, circumoral spines are absent and the entire body surface is covered with tegumental spines. Late juveniles show gradual differentiation of the circumoral tegument into a collar of spines associated with a reduction in density of tegumental spines at the posterior extremity of the body. Genital primordia appear when juveniles are about 1.75 mm long. The distributions of tegumental spines on adult A. spiniceps and A. absconditum are similar. Spines are denser on the dorsal and ventral surfaces of the anterior and middle parts of the body and less dense towards the posterior end. The tegumental fold surrounding the ventral sucker of A. absconditum has spines while the fold of A. spiniceps lacks them. The most important morphological features differentiating both species are the number of circumoral spines, body shape, ratio of body length to width, sucker sizes, and the presence or absence of spines on the ventral sucker.     

A new species of Saturnius Manter, 1969 (Digenea: Hemiuridae) from Mediterranean mullet (Teleostei: Mugilidae)

A new hemiurid digenean, Saturnius gibsoni n. sp., is described from the stomach lining of Mugil cephalus L. off Oran, Mediterranean coast of Algeria. Characteristic morphological features of the new species include small size of the body which is comprised of six pseudosegments, small ventral sucker, weakly developed mound-shaped flange at the level of the ventral sucker, and eggs being large in relation to the size of the body. Saturnius gibsoni n. sp. resembles S. minutus Blasco-Costa, Pankov, Gibson, Balbuena, Raga, Sarabeev & Kostadinova, 2006 and two unidentified Saturnius spp. in the small size of the body and most metrical features. However, in spite of the presence of five transverse septa resulting in six pseudosegments and the range overlap of some metrical features, the ventral sucker in S. minutus is much larger, the ventral sucker muscular flange is more prominent, the last pseudosegment is narrower in relation to body width and more rounded, and the eggs are smaller (mean 21 × 10 vs 25 × 12 μm). Furthermore, the partial sequences of the 28S rRNA gene region (domains D1–D3; 1,195 nt) obtained from two isolates of S. gibsoni n. sp. differed by 11 nt (0.9%) from that of S. minutus. Both unidentified forms of Saturnius are clearly distinguishable from S. gibsoni n. sp. by the presence of six stout, transverse muscular septa, forming seven pseudosegments (vs five septa forming six pseudosegments). Bayesian inference analysis of partial 28S rDNA sequences based on a total of 15 species from the families Hemiuridae and Lecithasteridae depicted the Bunocotylinae Dollfus, 1950 as a strongly supported basal clade, with Bunocotyle progenetica (Markowski, 1936) as the closest sister taxon to Saturnius spp.     

On the morphology and life-history of Hemiurus luehei Odhner, 1905 (Digenea: Hemiuridae)

Previously undescribed cystophorous cercariae which develop in sporocyst germinal sacs in the tectibranch opisthobranch Philine denticulata (Adams) are shown to be cercariae of Hemiurus luehei Odhner, 1905 (Hemiuridae), a common stomach parasite of clupeid and salmonid fishes off the Atlantic coast of Europe, in the Baltic and the Mediterranean Sea. The free-swimming cercariae are seized by calanoid copepods. Temora longicornis (Müller) and Acartia tonsa Dana acted as suitable experimental intermediate hosts. Pressure by the copepod mouth appendages causes delivery tube eversion and the injection of the cercarcial body into the haemocoel. Sagitta sp. was found naturally infected with a metacercaria of H. luehei. The cystophorous cercaria and metacercaria are described using light and scanning electron microscopy. Adults from herring were examined under the stereoscan electron microscope.     

Reevaluation of the taxonomic status of Halipegus occidualis Stafford, 1905 (Digenea: Hemiuridae)

In response to confusion regarding the taxonomy of halipegines inhabiting North American amphibians, the reproductive structures of the hemiurid Halipegus occidualis are described from adult worms reared from cercariae shed by Helisoma anceps from Charlie's Pond, North Carolina. The report of a Laurer's canal is confirmed and the presence of a canalicular seminal receptacle established. The suggestion that H. eccentricus Thomas, 1939 be considered a junior synonym of H. occidualis Stafford, 1905 is rejected.     

Halipegus eschi n. sp. (Digenea: Hemiuridae) in Rana vaillanti from Guanacaste Province, Costa Rica

Halipegus eschi n. sp. is described from the esophagus of Rana vaillanti from Guanacaste Province, Costa Rica. The new species differs from other known species of Halipegus on the basis of relative testis size, lateral extent of the uterus, vitelline follicle arrangement, egg size, and polar filament length.     

A new cryptic species of <Emphasis Type="Italic">Aponurus</Emphasis> Looss, 1907 (Digenea: Lecithasteridae) from Mediterranean goatfish (Teleostei: Mullidae)

The status of the trematode Aponurus laguncula Looss, 1907 in the western Mediterranean is re-assessed by means of a comparative morphological study and rDNA sequences based on newly collected material. A. laguncula (sensu stricto) is redescribed from Trachinus draco L. and a new cryptic species of the ‘A. laguncula complex’, Aponurus mulli n. sp., is described on the basis of abundant material from Mullus barbatus L. (type-host) and M. surmuletus L. off the Spanish Mediterranean coasts. The new species is differentiated from A. laguncula (sensu stricto) by its: significantly larger, elongate body, with maximum width at the level of the ventral sucker; shorter forebody; distinctly larger sinus-sac, seminal receptacle and seminal vesicle, with the latter also being more elongate; vesicular pars prostatica; more anteriorly located vitellarium, which consists of eight globular follicles; and distinctly smaller eggs, which are also smaller in relation to body size and have both their opercular and anopercular poles rounded. The variability and the allometric growth of the morphological characters in the new species were studied in detail, resulting in additional distinguishing features. Sequences of the large subunit rRNA (28S) gene (domains D1–D3) and ITS2 rRNA gene region for the new species have been submitted to GenBank in order to enhance future studies on species differentiation within the ‘A. laguncula complex’.     

Hemiuridae (Digenea) from marine fishes of the Great Barrier Reef,Queensland, Australia

The following species are described, figured and/or recorded from the Great Barrier Reef at Heron Island or Lizard Island, Queensland, with comparative material reported from other areas of the ocean around Australia or New Guinea: Dinurus longisinus (new synonym: D. hippuri) from Seriola lalandi, Heron Island and Coryphaena hippurus, Papua New Guinea; Ectenurus trachuri from Caranx sexfasciatus, Diploprion bifasciatus, Pterocaesio marri, Seriola lalandi and Atherinomorus capricorniensis, Heron Island; Erilepturus hamati (with 25 new synonyms) from Lutjanus carponotatus, Lizard Island, Platycephalus bassensis, Coff's Harbour, NSW, P. fuscus, Coff's Harbour, NSW and Moreton Bay, Queensland, P. endrachtensis, Sillago analis, S. maculata, S. ciliata, Pseudorhombus arsius and Polydactylus sp. from Moreton Bay, Queensland and Lates calcarifer, Darwin, Northern Territory; Tubulovesicula angusticauda from Echeneis naucrates and Lethrinus miniatus, Heron Island and Anguilla reinhardtii, Moreton Bay and Bribie Island, Queensland; Elytrophalloides humerus from Trachinotus botla and T. coppingeri, Heron Island; Lecithochirium kawakawa from Euthynnus affinis Heron Island and Lizard Island: Lecithochirium cirrhiti (new synonyms: L. sammarae, L. nohu) from Sargocentron rubrum, Heron Island; Lecithochirium caesionis from Pterocaesio marri, heron Island; Plerurus digitatus (new synonyms: P. cynoglossi, P. atulis, P. scomberomori) from Plectropomus leopardus, Heron Island, Lutjanus erythropterus, Variola louti, Scomberomorus semifasciatus, Grammatorcynus bicarinatus and Carangoides embureyi, C. gymnostethoides, Lizard Island, Scomberomorus commerson, Heron Island, Lizard Island, New Britain, Papua New Guinea, Point Lookout, Queensland and Moreton Bay, Queensland, Euthynnus affinis Heron Island, Lizard Island and New Britain, Papua New Guinea, Sphyraena barracuda, Heron Island and Lizard Island, Scomberomorus munroi, S. queenslandicus and Saurida undosquamis, Moreton Bay, Queensland and Chirocentrus dorab, Bundaberg, Queensland. The Lecithochirium species-group Cirrhiti is considered indistiguishable from the species-group Lotellae.     

Reproductive System of the Type Specimens of Urogonimus macrostomus (Rudolphi, 1803) Monticelli, 1888 (Digenea)

The reproductive system of the type specimens of Distoma macrostomum and D. ringens Rudolphi, 1819, has been reinvestigated. The shape and position of the cirrus, cirrus pouch, metraterm, "vesicula seminalis", gonads, vitellaria and uterus arrangements are given. This shows that the arrangement of the reproductive system in D. macrostomum (syn. D. ringens ) differs from that of the members of the genera Leucochloridium Carus, 1835 (sensu Kagan 1952) and Neoleucochloridium Kagan, 1951. It confirms as correct to place D. macrostomum as a separate genus, Urogonimus Monticelli, 1888.     

Hemiuridae (Digenea) from marine fishes of the southern Indian Ocean: Dinurinae,Elytrophallinae, Glomericirrinae and Plerurinae

The following species are described, figured and/or recorded from regions of the southern Indian Ocean: Dinurus longisinus from Coryphaena hippurus, Cape Province and Western Australia and immature in Carangoides gymnostethoides, Western Australia; Ectenurus trachuri from Trachurus declivis, Tasmania, Erilepturus tiegsi from Platycephalus endrachtensis, Pomatomus saltator and Arripis georgianus, Western Australia and Sphyraena novaehollandiae, Tasmania; Tubulovesicula angusticauda (with eight new synonyms) from Trachichthodes gerrardi, South Australia and Gymnothorax woodwardi, Saurida undosquamis and Argyrops spinifer, Western Australia; Elytrophalloides oatesi from Meuschenia freycineti and Aldrichetta forsteri, South Australia; Elytrophalloides humerus n. sp. from Trachinotus botla, Natal; Lecithocladium angustiovum (with four new synonyms) from Rastrelliger kanagurta, Natal; Glomericirrus amadai from Hoplostethus atlanticus, Tasmania; Plerurus digitatus (with 17 new synonyms) from Euthynnus affinis, Scomberomorus commerson, Thunnus albacares, Scomberoides commersonianus, Alectis ciliaris, Pomatomus saltator, Saurida undosquamis, Rachycentron canadum, Natal and Lichia amia and Pomatomus saltator, Cape Province and Carangoides gymnostethoides, Western Australia; Synapto-bothrium sp. from Pomatomus saltator, Western Australia.     

The Ultrastructure of the Daughter Sporocyst Tegument of Cercaria vaullegeardi Pelseneer (Digenea, Hemiuridae)

The body wall of the daughter sporocyst of Cercaria vaullegeardi Pelseneer, 1906 is unusual for a species without a birth pore in consisting of an outer anucleated, microvillous syncytial tegument and a cellular subtegument which lacks secretory cells. In contrast, most other known daughter sporocysts without birth pores have a nucleated region above the microvillous region of the tegument. The significance and functional aspects of this structure are discussed.     

Merlucciotrema praeclarum (Manter, 1934) (Digenea: Hemiuridae) redescribed from myctophiform and gadiform fishes of the North Atlantic

Merlucciotrema praeclarum (Manter, 1934) is redescribed from the deep-sea benthic fishes Bathysaurus mollis, B. ferox and Cataetyx laticeps from various localities in the northern Atlantic Ocean. The genus is close to Plerurus Looss, 1907, but is retained on the basis of the presence of a muscular sinus-organ and, possibly, a rudimentary or degenerate sinus-sac. The subfamily Plerurinae Gibson & Bray, 1979 and the genus Merlucciotrema are redefined.     

Molecular and morphological evidence for the Holarctic distribution of Urogonimus macrostomus (Rudolphi, 1803) Monticelli, 1888 (Digenea: Leucochloridiidae)

Species of Urogonimus Monticelli, 1888 (Leucochloridiidae Poche, 1907) are difficult to distinguish using adult morphology, and their taxonomy has been repeatedly subjected to revision. Some Nearctic species have been regarded as synonymous with the Palearctic type species Urogonimus macrostomus (Rudolphi, 1803) Monticelli, 1888. This implies that U. macrostomus is present in the Nearctic, but there is no additional evidence for this putative distribution. We collected trematodes morphologically indistinguishable from U. macrostomus from a house sparrow (Passer domesticus) in Edmonton, Alberta, Canada. Sequences 2958 bp in total length from the small and large subunits of ribosomal DNA from 2 specimens were 99.8-100% identical to those of U. macrostomus in the Ukraine and Japan. In light of the lack of morphological differences and small degree of genetic variation, we consider the specimens we collected to be conspecific with U. macrostomus in the Palearctic, and the Holarctic range of the species is thus supported. Sequences from a more rapidly evolving gene, cytochrome c oxidase 1, were obtained to aid future study of this and related species.     

Two Species of Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from Marine Fishes off Namibia,Including S. Beukelaardori n. sp.

Stephanostomum kovalevae Parukhin, 1968 from the intestine of Lophius vomerinus off Swakopmund, Namibia, is redescribed. It is characterised by its large number (c. 73-88) of circum-oral spines, its relatively very long hindbody and the vitellarium reaching close to or just overlapping the ventral sucker. S. beukelaardori n. sp., from the intestine of Zenopsis conchifera off Walvis Bay, Namibia, is described. It belongs to the group of species where the vitellarium reaches the ventral sucker, and which has c. 32-38 circum-oral spines. It is closest to S. casum (Linton, 1910), but differs in lacking the lining of prominent spines in the ejaculatory duct, probably in egg-size and in both forebody and hindbody lengths.