Male Copulatory Complex Research Articles

Morphological description and molecular characterisation of Dactylogyrus matlopong sp. n. (Monogenea: Dactylogyridae) from the South African endemic Labeobarbus aeneus (Cyprinidae: Torinae).

Dactylogyrus Diesing, 1850 is the most species-rich genus in Platyhelminthes, with over 900 documented species, that are mostly strictly specific to freshwater cyprinoids. The morphological Dactylogyrus groups afrobarbae-type, carpathicus-type, pseudoanchoratus-type, and varicorhini-type are known to occur in Africa. This study describes a new species of Dactylogyrus of the varicorhini-type from the gills of the endemic smallmouth yellowfish Labeobarbus aeneus (Burchell) from the Vaal River, Free State Province, South Africa. Dactylogyrus matlopong sp. n. is unique among its varicorhini-type congeners mainly by the accessory piece of the male copulatory complex that presents a hook-shaped subunit with defined round base not reaching the male copulatory organ, combined with the presence of a conspicuous medial projection on the anterior margin of the ventral bar. Sequences of the partial 28S and 18S rRNA genes, together with entire ITS1 region, were generated for the first time for a species of Dactylogyrus from South Africa. Concatenated phylogenetic analyses of selected Dactylogyrus spp. showed that these parasites group according to their morphological types.

Urocleidoides spp. (Monogenea: Dactylogyridae) from the gills of Parodon nasus (Characiformes: Parodontidae) from a Brazilian stream with descriptions of two new species.

Urocleidoides spp. are reported from the gills of 20 specimens of Parodon nasus (standard length 8.512 cm), from the Indiana stream, Tiet River, Upper Paran River basin, municipality of Botucatu, So Paulo State, Brazil. Urocleoidoides tenuis and two new species were found. Urocleidoides indianensis n. sp. differs from its congeners mainly by the morphology of the vaginal sclerite that is robust, sickle-shaped, and forked at the distal end; and by the bulbous-shaped accessory piece of the male copulatory complex. Urocleidoides parodoni n. sp. resembles U. tenuis by presenting male copulatory organ with approximately 7 counterclockwise rings, but differs by the morphology of the accessory piece (lobate with a small hook-like projection versus pincer-shaped), vaginal sclerite (thumb-like subterminal projection vs. presence of a distal hook), vaginal tube (conspicuously sclerotized vs. slightly sclerotized), shape of the ventral bar (bowed vs. wide V-shaped), ventral and dorsal anchors (robust base and short shaft vs. considerably less robust base and long shaft), and hooks (slender shank with a weakly sclerotized subunit at base vs. dilated shank). Sequences of the partial 28S rDNA gene of the dactylogyrids found in this study are provided. Phylogenetic analyses showed Urocledoides spp. from Parodontidae clustering together with strong support values. This study increases the number of valid Urocleidoides species to 39, and the number of species described from parodontid hosts to four.

Morphological and molecular identification of the invasive freshwater snail Physa acuta (Gastropoda: Physidae) into Llanquihue Lake, Chilean Patagonia.

The sewage snail Physa acuta, native to North America, is an effective invasive species around the world. In Chile, it was first reported in 2014 in the north central area of the country. So far, the species has not been recorded in southern Chile. Sampling performed in 2015 in three localities from Llanquihue Lake, Chilean Patagonia, only provided native freshwater snails. However, new collections performed in February 2018 in the same three sites were successful for physid specimens suggesting a biological invasion entailing a large southward range expansion of these snails. Here we performed morphological, microstructural and phylogenetic analyses to investigate whether the new samples belong to Physa acuta. The shell morphology, male copulatory complex and radula microstructure of the new material agree with those of the sewage snail. The molecular phylogenetic analyses using the cytochrome c oxidase subunit 1 (COI) gene confirmed morphological identification. We suggest to take prompt measures to prevent the expansion of Physa acuta in Llanquihue Lake or nearby aquatic ecosystems.

Monogenoidea (Dactylogyridae, Gyrodactylidae) from Red River Pupfish, Cyprinodon rubrofluviatilis (Cyprinodontiformes: Cyprinodontidae), from Kansas and Texas, USA.

The gills of Red River Pupfish (Cyprinodon rubrofluviatilis) collected from Kansas and Texas, U.S.A., were found to be infected with three monogenoideans, Fundulotrema prolongis, Gyrodactylus rubrofluviatilaen. sp., and a species of Salsuginus. Gyrodactylus rubrofluviatilae n. sp. appears to be a member of a group of six closely related species possessing hamuli with mesially folded roots and a linguiform ventral bar shield, and parasitizing closely related species of Cyprinodon of the North American Gulf Coast and inland waters of the Southwestern United States and northern México. Gyrodactylus rubrofluviatilae n. sp. differs from its close congeners in the morphology of the hamuli, ventral bar, ventral bar shield, and marginal hooks. Because the morphology of the male copulatory complex was not determined of what we believe will eventually be a new species of Salsuginus, a species description is deferred. This is the first report of any parasite from this host. ManyNorth American species currently recognized within the Cyprinodontiformes have not yet been surveyed for species of Fundulotrema, Gyrodactylus, or Salsuginus. This, coupled with the high host specificity generally recognized for these monogeneans, portends there are likely additional new species yet to be discovered.When possible, to help augment morphological data, further studies should employ comprehensiveintra- and interspecies molecular analyses to help resolve host-parasite phylogenies.

Three previous recorded species of Dactylogyrus Diesing, 1850 (Monogenea: Dactylogyridae) infecting cultured Carassius auratus in southern Brazil.

The present study aimed to contribute to the monogenean dactylogyrids that occur in C. auratus from an ornamental fish farm in southern Brazil. Samples of goldfish were obtained from a fish farm and the gills were removed and analysed to identify the species of Dactylogyrus to determine the levels of infestation. Three species of Dactylogyrus were found in the gills: Dactylogyrus anchoratus, Dactylogyrus baueri and Dactylogyrus formosus. The most prevalent species was D. baueri [prevalence (P) = 70%, mean intensity (MI) = 2.14 ± 1.21, mean abundance (MA) = 1.5 ± 1.43], followed by D. anchoratus (P = 60%, MI = 1.67 ± 0.81, MA = 1.00 ± 1.05) and D. formosus (P = 30%, MI = 1.66 ± 1.15, MA = 0.5 ± 1.64). Dactylogyrus anchoratus shares morphological characteristics with D. arcuatus by the similarity in shape of the haptor parts. Dactylogyrus baueri shows similarity to D. dulkeiti in relation to the pair of anchors and accessory piece of the male copulatory complex. Dactylogyrus formosus presents an accessory piece with branch and total length of the anchors smaller than D. anchoratus. This study reports the occurrence of D. anchoratus, D. baueri and D. formosus in goldfish cultured in southern Brazil. These monogenean species have been described in cyprinid fishes that have a wide geographic distribution with the result of the dissemination of the host in the world.

Monogenean fauna of alien tilapias (Cichlidae) in south China.

Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

Three-dimensional morphology of rigid structures as a tool for taxonomic studies of Dactylogyridae (Monogenea).

Dactylogyridae is overwhelmingly the most abundant and diverse taxon among monogeneans in continental waters of South America. Their small body size requires considerable sampling effort and training for collecting and identifying the worms from the gills, skin, nasal cavities, and other microhabitats. Indeed, diagnostic characteristics as sclerites and male copulatory complex are generally less than 100-μm long and are essential for taxonomic description and identification of species. Here, a combination of simple and routine methods for three-dimensional morphological studies on hard structures is proposed for dactylogirids: SDS treatment for clarification of specimens and enzymatic digestion with proteinase K for freeing sclerotized structures, followed by laser confocal microscopy. This method is applicable to fresh or fixed specimens and does not require staining or dehydration. Indeed, stable autofluorescence emission is detectable at 500-530nm for bars, anchors, and male copulatory complex when excited by argon laser. Advantages of this protocol over previous methodologies for taking laser confocal images are discussed. Open access software for image processing was used for three-dimensional reconstruction of sclerotized structures generating models and full 360° rotation videos.

A new genus and species of entocytherid ostracod (Ostracoda: Entocytheridae) from the John Day River Basin of Oregon, U.S.A., with a key to genera of the subfamily Entocytherinae.

Targeted sampling efforts by the authors for the signal crayfish, Pacifastacus leniusculus, from its native range in the John Day River Basin, Oregon, U.S.A. yielded entocytherid ostracods with a male copulatory complex so clearly different from other entocytherines that a new genus, Aurumcythere gen. nov. is proposed to receive them. This newly proposed, apparently nonsclerotized, genus with hook and spur-like prominences of the posteroventral end of the peniferum is the first new genus of the subfamily Entocytherinae named since Hobbs & Peters described Aphelocythere (= Waltoncythere) in 1977. Aurumcythere gen. nov. represents only the second genus of entocytherid known from the Pacific Northwest. Lack of sclerotization in Aurumcythere gen. nov. provides new insight into poorly understood mating behaviors of entocytherid ostracods.

A new species of Characithecium (Monogenea: Dactylogyridae) from external surface and gills of two species of Astyanax (Ostariophysi: Characidae) in southern Brazil

A new species of Characithecium, a genus of monogenean parasites of Neotropical characids, is described from specimens collected on the body surface and gills of Astyanax aff. fasciatus and Astyanax jacuhiensis from Lake Guaíba, State of Rio Grande do Sul, Brazil. The new species is similar to Characithecium costaricensis, but differs by having the haptor separated from the body by a long peduncle, and by having an accessory piece composed of 2 subunits in the male copulatory complex – 1 ventral pincer-shaped at the distal end, and 1 dorsal with an expanded rod-shaped proximal end and the distal end containing 3 elongated projections–, and the dorsal bar usually presenting a small median elevation in the anterior margin. This study increases the number of species of Characitecium to 7 and expands our knowledge on the diversity of monogenean parasites of characids.

Dactylogyrus olfactorius n. sp. (Monogenea, Dactylogyridae) from the olfactory chamber of the fathead minnow, Pimephales promelas Rafinesque (Cyprinidae).

Dactylogyrus olfactorius n. sp. (Monogenea) is described from the olfactory chamber of the fathead minnow Pimephales promelas Rafinesque in Alberta, Canada. The new species resembles Dactylogyrus bychowskyi Mizelle, 1937, D. bifurcatus Mizelle, 1937 and D. simplexus Mizelle, 1937, all parasites of Pimephales spp. in North America, in overall size and shape of the anchors and hooks, and in having a male copulatory complex with a tapered tubular penis and bifurcate accessory piece. Diagnostically, D. olfactorius n. sp. has relatively small anchors, hooks of anchor length, and a thin, long dorsal bar and no apparent ventral bar nor 4A hooks. Scanning electron microscopy revealed the body tegument of D. olfactorius n. sp. to be microvillous and in shallow annular folds, while that of D. bifurcatus, occurring on host gills of the same fish, was avillous and in gill-like folds dorsally and ventrally. Partial 28S rDNA sequences revealed significant differences between the two species, supporting establishment of D. olfactorius n. sp. and dispelling the possibility of ecophenotypic effects of site of attachment on morphology.

Two new species of Haliotrema Johnston & Tiegs, 1922 (Monogenea: Dactylogyridae) from Acanthurus nigrofuscus (Forsskål) and A. triostegus (Linnaeus) (Teleostei: Acanthuridae) in the South China Sea.

Haliotrema nanhaiense n. sp. and Haliotrema triostegum n. sp. are described respectively from the gills of Acanthurus nigrofuscus (Forsskål) and Acanthurus triostegus (Linnaeus) in the South China Sea. Haliotrema nanhaiense n. sp. differs from other existing congeneric species by its male copulatory complex, comprising a C-shaped copulatory tube, a saucer-shaped base and a sickle-shaped accessory piece. Haliotrema triostegum n. sp. can be differentiated from all other members of Haliotrema by having a unique copulatory complex, a cup-shaped base, inverted L-shaped copulatory tube with a small sclerotised piece arising from its distal portion, and a large accessory piece from the proximal portion of copulatory tube.

A new species of Mymarothecium and new host and geographical records for M. viatorum (Monogenea: Dactylogyridae), parasites of freshwater fishes in Brazil

Mymarothecium boegeri sp. n. (Monogenea: Dactylogyridae) is described from the gills of Colossoma macropomum Cuvier (Characidae), collected from the aquaria of the "Centro de Pesquisas em Aquicultura, Departamento Nacional de Obras Contra as Secas (DNOCS)", Pentecoste City, State of Ceará, Brazil. Mymarothecium viatorum Boeger, Piasecki et Sobecka, 2002 is reported from the type host, Piaractus brachypomus (Cuvier) (Characidae) and from a new host, P. mesopotamicus (Holmberg) (Characidae), confirming the occurrence of M. viatorum in the Neotropical Region. The new species differs from the congeneric species in the structure of male copulatory complex; it is more closely related to M. viatorum by the presence of a posteromedial projection on ventral bar.

Clemacotyle australis (Monogenea: Monocotylidae) from the White-Spotted Eagle Ray Aetobatus narinari (Rajiformes: Myliobatididae) on the Great Barrier Reef: Redescription, Emended Generic Diagnosis, and Oncomiracidium

Clemacotyle australis Young, 1967 from the branchial cavity of the type host, Aetobatis narinari, is redescribed based on new material from the type locality, Heron Island, Queensland, Australia. The generic diagnosis is emended to include details of the male copulatory complex. Oncomiracidia, hatched from eggs collected from C. australis, are noteworthy in the presence of diffuse pigment throughout the body and haptor.

Gill parasites of the genus Cichlidogyrus Paperna, 1960 (Monogenea, Ancyrocephalidae) from Tilapia guineensis (Bleeker, 1862), with descriptions of six new species

A study of gill parasites of Tilapia guineensis (Bleeker, 1862) (Cichlidae) from different locations in West Africa (Senegal, Guinea, the Ivory Coast and the Congo) revealed the presence of twelve species of Cichlidogyrus Paperna, 1960 (Monogenea). Six have been recorded previously from T. zillii (Gervais, 1848) or Tristamella simonis (Gunther, 1864) and six are considered new species: C. agnesi n. sp., C. bilongi n. sp., C. gallus n. sp., C. flexicolpos n. sp., C. louipaysani n. sp. and C. vexus n. sp. In the first three species cited, we report the presence of an auxiliary plate in the male copulatory complex which is characteristic of the species C. aegypticus Ergens, 1981, a parasite of Tilapia zillii.

Kritskyia moraveci n. g., n. sp. (Monogenea: Dactylogyridae) from the urinary bladder and ureters of Rhamdia quelen (Quoy & Gaimard, 1824) (Pisces: Pimelodidae) in Brazil

Kritskyia n. g. is proposed for K. moraveci n. sp. from the urinary bladder and ureters of Rhamdia quelen (Quoy & Gaimard, 1824), a pimelodid fish from the reservoir of the Hydroelectric Power Station of “Passo Fundo”, Rio Grande do Sul State, Brazil. The new genus is most closely related to Acolpenteron Fischthal & Allison, 1940, from which it differs by having a male copulatory complex composed of a coiled cirrus and a bipartite accessory piece, a sinistral vagina, and an antero-ventrally concave haptor which possesses 14 ventrally directed marginal hooks, but lacks an anterior rim and 4A hooks.

Callorhynchocotyle hydrolagi n. sp. (Monogenea: Hexabothriidae) from Hydrolagus ogilbyi (Chimaeriformes: Chimaeridae) in the South Pacific

Callorhynchocotyle hydrolagi n. sp. is proposed for hexabothriids found on the gills of the ghost shark, Hydrolagus ogilbyi, taken off the coast of southeastern Australia. The species is distinguished from the three previously described species of the genus in that the sclerites and the points of the sclerites of the three sucker pairs are all of similar size. The greater thickness of the sucker sclerites, the hamuli with inflated, almost spherical terminations of the roots, and the robust male copulatory complex also serve to differentiate C. hydrolagi.

Ancyrocephalids (Monogenea) from Morone spp. (Percichthyidae) in North America, including redescriptions of Onchocleidus mimus Mueller, 1936 and O. interruptus Mizelle, 1936

The ancyrocephalids (Monogenea) parasitizing the temperate basses (Percichthyidae) of North America are reviewed. Onchocleidus mimus Mueller, 1936 is redescribed from material found on the gills of Morone chrysops (white bass) taken in Ontario. Onchocleidus rogersi (Hanek and Fernando, 1972) Beverley-Burton, 1984 is declared a synonym of O. mimus. Onchocleidus interruptus Mizelle, 1936 is redescribed from paratype material (14 specimens) found on M. mississippiensis (yellow bass) taken in Illinois. Additional morphometric and morphologic data for O. chrysops (Mizelle and Klucka, 1953) Beverley-Burton, 1984 are provided. Cleidodiscus sp. of S. Tedla and C. H. Fernando and "Tetraonchinae" of C. J. Sindermann are considered to be referrable to the genus Onchocleidus sensu Beverley-Burton. Following a study of type specimens of Aristocleidus hastatus Mueller, 1936 from M. saxatilis (striped bass) taken in Florida, the genus and species are recognised as valid. However, there is need for a revision of the generic diagnosis when new material becomes available as the morphology of the male copulatory complex appears to be distinctive and of a "type" as yet undescribed. Urocleidus nactus Mayes and Johnson, 1975 found on M. americana (white perch) taken in coastal waters of North Carolina is transferred to Pterocleidus Mueller, 1937 as Pterocleidus nactus (Mayes and Johnson, 1975) n. comb. The possibility that ancyrocephalids found on M. americana taken in estuarine waters of the Hudson River by V. M. Liguori and identified as U. biramosus (Mueller, 1937) are conspecific with P. nactus is discussed. Ancyrocephalids possessing the spiral filament penis type occur almost exclusively on fishes of the Percoidae. Possible evolutionary pathways involving ancestral dactylogyridans (sensu Beverley-Burton) parasitizing estuarine Percichthyidae or freshwater Centrarchidae are presented with particular reference to the ancryrocephalids found on Morone spp.

The Taxonomic Status of Actinocleidus Mueller, 1937; Anchoradiscus Mizelle, 1941; Clavunculus Mizelle et al., 1956; Anchoradiscoides Rogers, 1967; Syncleithrium Price, 1967 and Crinicleidus n. gen.: North American Ancyrocephalids (Monogenea) with Articulating Haptoral Bars

The ancyrocephalids (Monogenea) with articulated or fused transverse haptoral bars and which parasitize North American centrarchid fishes are reviewed. Actinocleidus Mueller, 1937, with A. oculatus (Muel- ler, 1934) Mueller, 1937, as type species, and A. articularis (Mizelle, 1936) Mueller, 1937; A. fergusoni Mizelle, 1938; A. brevicirrus Mizelle and Jaskoski, 1942; A. bifidus Mizelle and Cronin, 1943; A. recurvatus Mizelle and Donahue, 1944; A. georgiensis Price, 1966, and A. bennetti Allison and Rogers, 1970, as additional species, is redefined. A key to Actinocleidus spp. is provided. The following, due to inadequate description and/or absence of identifiable type material, are regarded as species inquirendae: A. gracilis Mueller, 1937; A. maculatus Mueller, 1937; A.flagellatus Mizelle and Seamster, 1939; A. okeechobeensis Mizelle and Seamster, 1939; A. subtriangularis Mizelle and Jaskoski, 1942; A. bakeri Mizelle and Cronin, 1943; A. harquebus Mizelle and Cronin, 1943; A. gibbosus Mizelle and Donahue, 1944; A. incus Mizelle and Donahue, 1944. Anchoradiscus Mizelle, 1941, with A. anchoradiscus Mizelle, 1941, as type species, is redefined. Actinocleidus triangularis Summers, 1937, is, by the rule of tautonymy, regarded as a synonym of A. anchoradiscus. Clavunculus Mizelle, Stokely, Jaskoski, Seamster and Monaco, 1956, with C. bursatus (Mueller, 1936) Mizelle, Stokely, Jaskoski, Seamster and Monaco, 1956, as type species and C. bifurcatus (Mizelle, 1941) Mizelle, Stokely, Jaskoski, Seamster and Monaco, 1956, as an additional species is redefined. Clavunculus unguis (Mizelle and Cronin, 1943) Mizelle, Stokely, Jaskoski, Seamster and Monaco, 1956 and Actinocleidus mizellei Hanek and Fernando, 1972 (in part) are regarded as synonyms of C. bursatus. A key to Clavunculus spp. is provided. Anchoradiscoides Rogers, 1967, with A. serpentinus Rogers, 1967, as type species, is redefined. Syncleithrium Price, 1967, with S. fusiformis (Mueller, 1934) Price, 1967, as type species, is redefined. Crinicleidus n. gen. is proposed to accommodate C. crinicirrus (Kritsky and Leiby, 1973) n. comb. as type species and C. longus (Mizelle, 1938) n. comb. as an additional species. The genera Actinocleidus, Anchoradiscus, Clavunculus and Anchoradiscoides are similar with respect to the male copulatory complex but are separated on the functional morphology of the sclerotized components of the haptor. Syncleithrium and Crinicleidus are characterized by each having a distinctive male copulatory complex, which is unlike that of the above listed genera as well as distinctive haptoral sclerites. The types of the male copulatory complexes of Syncleithrium and Crinicleidus are herein described for the first time.

The Reproductive System of Oopelta polypunctata Collinge and O. nigropunctata Morch (Pulmonata, Arionidae?), with Reflections upon the Systematic Position of the Subfamily Oopeltinae

A morphological and histological description of the reproductive system of O. polypunctata and O. nigropunctata is given and probable ancestral and derived features evaluated. As Oopelta possesses a composite male copulatory complex, the conditions that could lead to the evolution of such a complex were pointed out. These guidelines were used to establish some of the morphological differences that exist between the reproductive system of the Oopeltinae and that of the other subfamilies of the Arionidae. As a result of the differences encountered in the reproductive system, as well as the differences in the buccal retractor muscles, the central nervous system and the jaw, inter alia, and the “disjunct” distribution of the Oopeltinae, the inclusion of this subfamily in the Arionidae seems questionable. Due to lack of information a new sister group could not be pointed out.