A review of the Apocreadiidae Skrjabin, 1942 (Trematoda: Digenea) and description of Australian species

The Apocreadiidae is reviewed and is considered to include genera recognised previously within the families Apocreadiidae, Homalometridae, Schistorchiidae, Sphincterostomatidae and Trematobrienidae. Key features of the family are extensive vitelline follicles, eye-spot pigment dispersed in forebody, I-shaped excretory vesicle, no cirrus-sac and genital pore opening immediately anterior to the ventral sucker (usually) or immediately posterior to it (Postporus Manter, 1949). Three subfamilies and 18 genera are recognised within the Apocreadiidae. The Apocreadiinae comprises Homalometron Stafford, 1904 (new syn. Barbulostomum Ramsey, 1965), Callohelmis n. g., Choanodera Manter, 1940, Crassicutis Manter, 1936, Dactylotrema Bravo-Hollis & Manter, 1957, Marsupioacetabulum Yamaguti, 1952, Microcreadium Simer, 1929, Myzotus Manter, 1940, Neoapocreadium Siddiqi & Cable, 1960, Neomegasolena Siddiqi & Cable, 1960, Pancreadium Manter, 1954, Procaudotestis Szidat, 1954 and Trematobrien Dollfus, 1950. The Schistorchiinae comprises Schistorchis Lühe, 1906, Sphincterostoma Yamaguti, 1937, Sphincteristomum Oshmarin, Mamaev & Parukhin, 1961 and Megacreadium Nagaty, 1956. The Postporinae comprises only Postporus. A key to subfamilies and genera of the Apocreadiidae is provided. It is argued that there is no convincing basis for the recognition of the genus Apocreadium Manter, 1937 and all its constituent species are combined with Homalometron. The following new combinations are proposed for species previously recognised within Apocreadium: Homalometron balistis (Manter, 1947), H. caballeroi (Bravo-Hollis, 1953), H. cryptum (Overstreet, 1969), H. longisinosum (Manter, 1937), H. manteri (Overstreet, 1970), H. mexicanum (Manter, 1937) and H. vinodae (Ahmad, 1985). Apocreadium uroproctoferum Sogandares-Bernal, 1959 is found to lack a uroproct and is made a synonym of H. mexicanum. Homalometron verrunculi nom. nov. is proposed to replace the secondarily pre-occupied H. caballeroi Lamothe-Argumedo, 1965. Barbulostomum is made a synonym of Homalometron and H. cupuloris (Ramsey, 1965) n. comb. is proposed. Neochoanodera is made a synonym of Choanodera and Choanodera ghanensis (Fischthal & Thomas, 1970) n. comb. is proposed. Species within the Apocreadiinae and Postporinae are reviewed and the following are recorded or described from Australian fishes: Homalometron wrightae n. sp. from Achlyopa nigra (Macleay), H. synagris (Yamaguti, 1953) n. comb. from Scolopsis monogramma (Cuvier), H. stradbrokensis n. sp. from Gerres subfasciatus Cuvier, Marsupioacetabulum opallioderma n. sp. from G. subfasciatus, Neoapocreadium karwarensis (Hafeezullah, 1970) n. comb. from G. subfasciatus, N. splendens n. sp. from S. monogramma and Callohelmis pichelinae n. g., n. sp. from Hemigymnus melapterus (Bloch), H. fasciatus (Bloch), Stethojulis bandanensis (Bleeker) andChoerodon venustus (De Vis). Callohelmis is recognised by the combination of absence of tegumental spines, caeca terminating midway between the testes and posterior end of body, ventral sucker enclosed in a tegumental pouch, prominent muscles radiating through the body from the ventral sucker, vitelline follicles not extending into the forebody, and a very short excretory vesicle that opens ventrally. New combinations for species previously recognised within Crassicutis are proposed as follows: Neoapocreadium caranxi (Bilqees, 1976) n. comb., N. gerridis (Nahhas & Cable, 1964) n. comb., N. imtiazi (Ahmad, 1984) n. comb. and N. marina (Manter, 1947) n. comb. The host-specificity and zoogeography of the Apocreadiinae are considered.     

Potential interactions between the intestinal helminths of the cichlid fish Cichlasoma synspilum from southeastern Mexico

This study presents and analyzes positional data on 18 helminth species forming the intestinal infracommunities of 59 Cichlasoma synspilum from southeastern Mexico. Interspecific interactions were found between 4 pairs of host specialists: Crassicutis cichlasomae (Digenea) with Neoechinorhynchus golvani (Acanthocephala), Spirocamallanus rebecae (Nematoda) with N. golvani, and Raillietnema kritscheri (Nematoda) with N. golvani. The interactions were expressed as negative correlations, positional shifts, and reductions in realized distribution. It is suggested that N. golvani produces unsuitable habitats for C. cichlasomae, S. rebecae, and R. kristscheri. All interactions were found among phylogenetically unrelated helminth specialists of cichlids.     

Two new species of rhabdochonids (Nematoda: Rhabdochonidae) from freshwater fishes in Mexico, with a description of a new genus

Two new nematode species, Beaninema nayaritense n. gen., n. sp. and Rhabdochona xiphophori n. sp., are described on the basis of the specimens recovered from the gall bladder and intestine of 2 fishes, Cichlasoma beani (Jordan) (Cichlidae, Perciformes) and Xiphophorus sp. (Poeciliidae, Cyprinodontiformes), respectively, from Mexico. The monotypic genus Beaninema differs from other rhabdochonid genera mainly in the presence of large conical teeth in the middle of the prostom. Rhabdochona xiphophori is characterized mainly by a unique structure of the prostom (presence of 6 anterior teeth; dorsal and ventral teeth unusually broad, with 2 lateral horns) and the shape of the deirids (bifurcated, with markedly long base).     

Monogeneans on native and introduced freshwater fishes from Cuba with the description of a new species of Salsuginus Beverley-Burton, 1984 from Limia vittata (Poeciliidae)

During a parasitological survey carried out between March and September 2003 in Cuba, the following monogeneans were found on the gills of freshwater fishes: Salsuginus cubensis n. sp. on the Cuban molly Limia vittata Guichenot (Poeciliidae); Cichlidogyrus sclerosus Paperna & Thurston, 1969 and C. tilapiae Paperna, 1960 on the African cichlid Tilapia rendalli Boulenger (Cichlidae); Haplocleidus dispar Mueller, 1936 and Pterocleidus acer Mueller, 1936 (all Dactylogyridae) on the sunfish Lepomis macrochirus Rafinesque (Centrarchidae) (new geographical records); and Gyrodactylus sp. (Gyrodactylidae) on the biajaca Nandopsis tetracanthus Valenciennes (Cichlidae) (new host and geographical record). Salsuginus cubensis differs from all other species of the genus in the size and morphology of the copulatory complex. The occurrence of C. sclerosus, C. tilapiae, H. dispar and P. acer in their respective hosts is due to the introduction of these hosts to Cuba. A review of the species composition of the Monogenea in native and introduced freshwater fish from Cuba is presented and the zoogeographical distribution of the species found is briefly discussed.     

A new species of Oochoristica (Eucestoda: Cyclophyllidea) parasite of Ctenosaura pectinata (Reptilia: Iguanidae) from Oaxaca, Mexico

During January 2002, 3 specimens of an undescribed species of Oochoristica Lühe, 1898, were collected in Ctenosaura pectinata (Wiegmann, 1834) from Santa Mará Mixtequilla, Oaxaca, Mexico. Oochoristica leonregagnonae n. sp. differs from 71 of 82 species of the genus by its large number of testes (78-112 [95] vs. less than 65 per proglottid, respectively). In addition, the numerous ovarian lobes (31-79 [51]) possessed by the new species distinguish it from the other 10, with a maximum of 20 ovarian lobes. The new species differs from Oochoristica acapulcoensis Brooks, Pérez-Ponce de León and García-Prieto, 1999, which also infects C. pectinata in Mexico, by the presence of numerous staining granules throughout the parenchyma of the scolex in the latter species; likewise, testes in O. acapulcoensis reach and even overpass the excretory canals, whereas in the new species they are limited to the central region between these tubules.     

Five new species of Urocleidoides (Monogenoidea) (Mizelle and Price 1964) Kritsky, Thatcher, and Boeger, 1986, parasitizing the gills of Panamanian freshwater fishes

During an investigation of gill monogenoidean parasites from freshwater fishes in central Panama, 5 new species of Urocleidoides (sensu stricto) were found: Urocleidoides cultellus n. sp., Urocleidoides visiofortatus n. sp., and Urocleidoides advenai n. sp. from the gymnotiform Brachyhypopomus occidentalis (Hypopomidae); Urocleidoides neotropicalis n. sp. and Urocleidoides piriatiu n. sp. from the characiforms Saccodon dariensis (Parodontidae) and Ctenolucius beani (Ctenoluciidae), respectively. Our findings represent the first known species of Urocleidoides from these fishes in Central America and demonstrate that they are morphologically linked to their South American congeners.     

Monticellia ophisterni n. sp. (Cestoda: Monticelliidae) from the swamp-eel Ophisternon aenigmaticum (Synbranchiformes) from Mexico.

Monticellia ophisterni n. sp. is described from the swamp-eel Ophisternon aenigmaticum Rosen and Greenwood (Synbranchiformes: Synbranchidae) from Lake Catemaco, Veracruz, Mexico. The new species is placed into Monticellia because of the cortical position of the testes, ovary, and uterus. It differs from other Monticellia species (with the exception of Monticellia magna (Rego, Santos and Silva, 1974)) in the position of longitudinal musculature that crosses the vitelline follicles, making them paramuscular. The new species can be distinguished from M. magna--which possesses a similar number of testes (107-139), paramuscular vitelline follicles, and numerous gland cells distributed between the apex of the scolex and suckers--in the position of the genital pore (8-21% vs. 19-27%), in the presence of a weak internal longitudinal musculature, in the arrangement of the testes in the median field, and in the absence of a vaginal sphincter. This is the first proteocephalidean tapeworm reported from a synbranchid fish and the first species of Monticellia found in North America.     

New parasite identified in Blennius sanguinolentus Pallas, 1811: Schikhobalotrema longivesiculatum sp. n (Haplosplanchnidae Poche, 1925)]

Schikhobalotrema longivesiculatum sp.n from Blennius sanguinolentus Pallas, 1811 at Gulf of Gaeta (Italy) is described, figured and compared with other species of the genus Schikhobalotrema Skrjabin et Guschanskaja, 1955. Schikhobalotrema longivesiculatum differs from Schikhobalotrema obtusa (Linton, 1916) Skrjabin et Guschanskaja, 1955, especially for sucker ratio, lobed ovary, seminal vesicle coiled and in larger size of eggs; from Schikhobalotrema pomacentri (Manter, 1937) Skrjabin et Guschanskaja, 1955 for lobed ovary, elongated seminal receptacle, smaller vitelline follicles and coiled seminal vesicle; from Schikhobalotrema sparisomae (Manter, 1937) Skrjabin et Guschanskaja, 1955 for elongated seminal receptacle, coiled seminal vesicle and extent of escretory vesicle.     

A new species of Gnathostoma (Nematoda: Gnathostomatidae) in Procyon lotor hernandezii from Mexico

Gnathostoma lamothei n. sp., inhabiting the stomach of Procyon lotor hernandezii Wagler, 1831, in Tlacotalpan, Veracruz State, and Rio Sapo, Oaxaca, Mexico, is described. This new species differs from all other congeners by having the posterior half of the body surface covered by rows of tiny round bosses instead of spines, or lacking ornamentations. Sequences of the ITS2 of the ribosomal DNA of G. lamothei n. sp. are compared with sequences of other species of the genus recorded in Mexico; they show a wide divergence (<50%) with Gnathostoma binucleatum Almeyda-Artigas, 1991, and Gnathostoma turgidum Stossich, 1902, and high similarity with Gnathostoma sp. I sequence (99.2%). On the basis of morphometric traits and sequences, previous records of Gnathostoma sp. I (=Gnathostoma procyonis of Almeyda-Artigas et al., 1994, not Chandler, 1942, and Gnathostoma neoprocyonis nomen nudem) in Mexico are referred to as the new species.     

A new cryptogonimid (Digenea) from the Mayan cichlid, Cichlasoma urophthalmus (Osteichthyes: Cichlidae), in several localities of the Yucatán Peninsula, Mexico

Oligogonotylus mayae n.sp. is described from the intestine of the Mayan cichlid Cichlasoma urophthalmus (Günther) in Ría Lagartos, Ría Celestún, and Estero Progreso, Yucatán State. This is the second species described for Oligogonotylus Watson, 1976, the other being O.manteri Watson, 1976. The new species is readily distinguished from O. manteri by the anterior extension of the vitelline follicles. In O. Manteri, Vitelline follicles are found entirely in the hindbody, extending posteriorly to mid-testicular level. Vitelline follicles in the new species extend from teh anterior margin of posterior testis to the region between the bentral sucker and the pharynx. comparison of approximately 1,850 bases of ribosomal DNA (ITS1, ITS2, 5.8S, and 28S), and 400 bases of cytochrome c oxidase subunit I (cox1) strongly supports the status of O. mayae as a new species, as compared to O. manteri collected from cichlids in other localities of Mexico, Belize, and Guatemala.     

Carettacola hawaiiensis n. sp. (Trematoda: Spirorchidae) from the green turtle, Chelonia mydas, in Hawaii.

Carettacola hawaiiensis n. sp. (Trematoda: Spirorchidae) is described from the hepatic vessels of the green turtle, Chelonia mydas (L.), in Hawaii. The new species differs from any previously described species of Carettacola in size, placement of vitellaria, and shape and placement of Laurer's canal. The genus Haemoxenicon Martin and Bamberger, 1952, becomes a synonym of Carettacola Manter and Larson, 1950. Haemoxenicon stunkardi Martin and Bamberger, 1952, is transferred to the genus Carettacola Manter and Larson, 1950, and becomes Carettacola stunkardi n. comb. An emended generic diagnosis for Carettacola is given along with a key to the species.     

The Pseudoplagioporinae,a new subfamily in the Opecoelidae Ozaki, 1925 (Trematoda) for a small clade parasitizing mainly lethrinid fishes,with three new species

The Pseudoplagioporinae n. subf. (Opecoelidae) is proposed for species of Pseudoplagioporus Yamaguti, 1938, Fairfaxia Cribb, 1989, and Shimazuia Cribb, 2005, a small group of relatively distinctive, Indo-West Pacific taxa reliably known almost entirely from emperor fishes (Perciformes: Lethrinidae). These taxa were previously recognized in the Plagioporinae Manter, 1947, but that subfamily has recently been restricted to a clade of Holarctic, freshwater taxa, whereas analyses of new genetic data find the pseudoplagioporines to form a distinct clade among a larger assemblage of marine taxa. New material was sourced from fishes collected mainly in Queensland waters, Australia, but with some specimens from off Western Australia, the Northern Territory, and Japan. Orthodena tropica Durio & Manter, 1968 is transferred to Pseudoplagioporus as P. tropicus (Durio & Manter, 1968) n. comb., and Orthodena Durio & Manter, 1968 thus becomes a synonym of that genus. Three new species of Pseudoplagioporus are proposed. One, P. mediocris n. sp., like other species of Pseudoplagioporus, occurs in several species of Lethrinus. The other two new species, P. labiatus n. sp. and P. roseovulatus n. sp., apparently do not infect species of Lethrinus and were instead found only in the Bigeye emperor Monotaxis grandoculis (Forsskål) and the Redfin emperor M. heterodon (Bleeker), respectively. New host-locality combinations and the first genetic data, for the ribosomal ITS2 DNA region, and the 28S rRNA, 18S rRNA, and cox1 mtDNA genes, are reported for Pseudoplagioporus lethrini Yamaguti, 1938, P. interruptus Durio & Manter, 1968, P. tropicus, Fairfaxia lethrini Cribb, 1989, Fairfaxia cribbi Hassanine & Gibson, 2005, and Shimazuia lethrini (Yamaguti, 1938) Cribb, 2005.     

Paracreptotrema blancoi n. gen., n. sp. (Digenea: Plagiorchiformes: Allocreadiidae) in the Olomina, Priapichthys annectens (Osteichthyes: poeciliidae), from the Area de Conservación Guanacaste, Costa Rica

A new species of allocreadiid digenean is described from Priapichthys annectens (Regan) (Osteichthyes: Poeciliidae) in the Area de Conservación Guanacaste, Costa Rica. A new genus, Paracreptotrema, is proposed to accommodate this species as well as Fellodistomum mendezi Songandares-Bernal, 1955, which was previously described from another poeciliid, Brachyrhaphis episcopi, in Panama. Paracreptotrema differs from all other nominal genera of Allocreadiidae by a combination of its symmetrical testes, restricted vitellaria, and the lack of oral lappets (muscular 'papillae') or other such appendages. Paracreptotrema blancoi n. sp. resembles Creptotrema creptotrema Travassos, Artigas and Pereira, 1928, but differs in lacking ventral oral lappets and in having vitellaria extending posteriorly only to the level of the testes. It can be distinguished from P. mendezi n. comb. in having a relatively larger and more posteriorly placed acetabulum, vitellaria that are more restricted anteriorly, smaller testes, and a uterus that does not extend to the posterior end of the body. The genus seems to be restricted to poeciliids in Central America.     

Culuwiya cichlidorum n. sp (Digenea: Haploporidae) from the black-belt cichlid Vieja maculicauda (Pisces: Cichlidae) from Nicaragua

A new haploporid trematode, Culuwiya cichlidorum n. sp., is described from the intestine of the black-belt cichlid Vieja maculicauda (=Cichlasoma maculicauda (Regan)) from the Atlantic coast of Nicaragua. It differs from congeneric species from freshwater and estuarine mugilid, cichlid, and gobiid fishes, previously placed to Saccocoelioides Szidat, 1954, and Carassotrema Park, 1938, in possessing the intestinal ceca reaching up to the posterior half of the testis and a bipartite, swollen external seminal vesicle. The new species also is characterized by a small, pyriform body, a well-developed prepharynx, a large pharynx, extensive vitelline follicles, confluent posterior to the testis that is situated near the posterior extremity, a uterus limited to the pretesticular and postacetabular region, and few, but relatively large, eggs (67-81 x 36-47 microm, i.e., about 12-14% of the body length) and miracidia without eye-spots. Culuwiya cichlidorum is also reported from Tomocichla tuba (Meek) in Nicaragua and species of Cichlasoma, Herichthys, Oreochromis, Parachromis, Petenia, Theraps, and Vieja from Mexico.     

<Emphasis Type="Italic">Mayarhynchus karlae</Emphasis> n. g., n. sp. (Acanthocephala: Neoechinorhynchidae), a parasite of cichlids (Perciformes: Cichlidae) in southeastern Mexico,with comments on the paraphyly of <Emphasis Type="Italic">Neoechynorhynchus</Emphasis> Stiles &amp; Hassall, 1905

Mayarhynchus n. g. (Acanthocephala: Neoechinorhynchidae) is erected for Mayarhynchus karlae n. g, n. sp. described from the intestine of four species of cichlid fishes distributed from southeastern Mexico. The new genus placed in the family Neoechinorhynchidae (Ward, 1917) Van Cleave, 1928, is readily distinguished from the other 17 genera in the family by having a small proboscis armed with 45–46 relatively weak rooted hooks arranged in nine longitudinal rows of five hooks each. In addition, Mayarhynchus n. g., n. sp. is diagnosed by the presence of a short trunk, body wall with five dorsal and one ventral giant hypodermal nuclei, proboscis receptacle nearly cylindrical with single layered wall, lemnisci broad and flat with large nuclei, testes in tandem, cement gland with eight large nuclei, and eggs elongate to oval. Partial sequences of the cytochrome c oxidase subunit 1 (cox1), internal transcribed spacers (ITS1 + 5.8S + ITS2), and the D2-D3 domains of the large subunit rRNA gene (28S) were obtained for five specimens of the new species and other species belonging to the Neoechinorhynchidae. Phylogenetic analyses confirmed that the new genus belongs to the Neoechynorhynchidae and indicated that the genus Neoechynorhynchus Stiles & Hassall, 1905 is not monophyletic. Comparison between three populations of the new species yielded nine variable sites for cox1, 11 for ITS and four for 28S.     

Sympatric species of Deretrema Linton, 1910: D. combesae n. sp. and D. combesorum n. sp. (Digenea: Zoogonidae) from the manybar goatfish Parupeneus multifasciatus (Quoy & Gaimard, 1824) (Perciformes: Mullidae) from New Caledonia

Two sympatric species of Deretrema, D. combesae n. sp. and D. combesorum n. sp. are described from the manybar goatfish Parupeneus multifasciatus from off New Caledonia, South Pacific. D. combesae n. sp. does not fit any of the described Deretrema subgenera. The combination of the characters, tegumental spines, caeca reaching past the testes, the vitellarium reaching into the hindbody, much of the uterus at the level of and anterior to the gonads, a long oesophagus, testes in the hindbody and the pre-testicular ovary are not found in any of the described subgenera. D. combesorum n. sp. fits into the subgenus Deretrema (Deretrema), but differs from the described species in the sucker-ratio, eggs size, elongate shape and contiguous testes. The sympatry of these dissimilar species of Deretrema casts doubt on the value of the subgenera in Deretrema.     

Gill monogeneans of neotropical cichlid fish: diversity,phylogenetic relationships,and host-parasite cophylogenetic associations

Host-parasite coevolution is one of the main topics of the evolutionary biology of host-parasite associations. The majority of monogeneans parasitizing fish exhibit a high degree of host specificity. As a result, their evolutionary history might be intertwined with that of their fish hosts. The Cichlidae represent a diverse group of secondary freshwater fish with disjunctive distribution. Host-specific dactylogyrid monogeneans commonly parasitize cichlid fish. Their high diversity is associated with the main areas of cichlid distribution, i.e., Neotropical America and Africa. Nevertheless, the parasite fauna of cichlids from Neotropical America is still underexplored. A total of 31 cichlid species were examined for the presence of monogeneans, with 20 of them being parasitized. On these cichlids, 30 monogeneans belonging to the genera Gussevia, Trinidactylus, and Scadicleithrum were identified, 17 of them potentially representing new species for science. Phylogenetic analyses revealed three monophyletic groups of Neotropic cichlid monogeneans. Genus Gussevia was monophyletic, while Sciadicleithrum resulted polyphyletic. Sciedicleithrum from South America and Sciadicleithrum from Mexico represented two divergent lineages. The plesiomorphic Neotropical cichlid host group for dactylogyrid monogeneans was Cichlini, from which the representatives of other Neotropical cichlid tribes were colonised. Cophylogenetic analyses revealed a statistically significant cophylogenetic signal in the investigated host-parasite system, with host switch and duplication representing the main coevolutionary events for monogeneans parasitizing Neotropical cichlids. This scenario is in accordance with previous studies focussed on dactylogyridean monogeneans parasitizing freshwater fish in Europe and Africa.     

Two new blood flukes (Digenea: Sanguinicolidae) from Epinephelinae (Perciformes: Serranidae) of the Pacific Ocean

Pearsonellum pygmaeus n. sp. is described from Cromileptes altivelis (Serranidae), the Barramundi Cod, from Heron Island (southern Great Barrier Reef) and Lizard Island (northern Great Barrier Reef). This new species differs from Pearsonellum corventum (type and only species) in the combination of smaller overall body size, the relative distance of the brain from the anterior end, the relative lengths of both the oesophagus and the testis, the degree to which the testis extends outside the intercaecal field, the shape of the testis, the shape and size of the ovary and the extent to which the uterus loops around the ovary. There are in addition, 20 base pair differences between the ITS2 rDNA sequence of P. pygmaeus n. sp. and that of P. corventum. Three new host records for P. corventum are reported. Adelomyllos teenae n. g., n. sp. is described from Epinephelus coioides (Serranidae), the Estuary Cod, from Moreton Bay, southeast Queensland. The new genus differs from the 22 other sanguinicolid genera in the combined possession of two testes, a cirrus-sac, separate genital pores, a post-ovarian uterus and an H-shaped intestine. A. teenae n. sp. is the third sanguinicolid described from the Epinephelinae. Sanguinicolids have now been reported from 11 species of Serranidae.