A phylogenetic analysis and revised classification of the Monocotylidae Taschenberg, 1879 (Monogenea)

The Monocotylidae Taschenberg, 1879 is revised based on a cladistic analysis of relationships between the constituent species and genera. The monophyly of the family is supported by three apomorphic character states: division of the haptor into one central and eight peripheral loculi; the ovary looping the right intestinal caecum; and tetrahedral eggs. The family is divided into six subfamilies: Calicotylinae Monticelli, 1903 (comprising Calicotyle Diesing, 1850, Dictyocotyle Nybelin, 1941); Dasybatotreminae Bychowsky, 1957 (comprising Anoplocotyloides Young, 1967, Dasybatotrema Price, 1938, Timofeevia n. g., Troglocephalus Young, 1967); Decacotylinae n. subfam. (comprising Decacotyle Young, 1967, Papillicotyle Young, 1967); Heterocotylinae n. subfam. (comprising Heterocotyle Scott, 1904, Neoheterocotyle Hargis, 1955, Nonacotyle Ogawa, 1991, Potamotrygonocotyle Mayes, Brooks & Thorson, 1981, Spinuris Doran, 1953); Merizocotylinae Johnston & Tiegs, 1922 (comprising Cathariotrema Johnston & Tiegs, 1922, Empruthotrema Johnston & Tiegs, 1922, Merizocotyle Cerfontaine, 1894, Squalotrema Kearn & Green, 1983, Triloculotrema Kearn, 1993); and Monocotylinae Taschenberg, 1879 (comprising Clemacotyle Young, 1967, Dendromonocotyle Hargis, 1955, Monocotyle Taschenberg, 1878). The Dendromonocotylinae Hargis, 1955 is removed from subfamilial status and the two genera previously assigned to the subfamily are reassigned to the Monocotylinae. Timofeevia is proposed for Timofeevia rajae (Timofeeva, 1983) n. comb. (formerly Dasybatotrema rajae). Mycteronastes Kearn & Beverley-Burton, 1990 and Thaumatocotyle Scott, 1904 are synonymised with Merizocotyle. Gymnocalicotyle Nybelin, 1941 is not considered a distinct taxon. Revised diagnoses and keys for subfamilies and genera of the Monocotylidae are provided.     

A new species of Monocotyle taschenberg, 1878 (Monogenea: Monocotylidae) from Dasyatis guttata (Dasyatidae)

Monocotyle guttatae n. sp. is described from the gills of the ray Dasyatis guttata (Bloch and Schneider, 1801) (Dasyatidae) off the coast of Brazil The new species can be readily differentiated from the other species of the genus in having a male copulatory organ with 2 loops and an accessory piece, 5-7 sclerites on the marginal haptoral papillae, and the absence of accessory sclerites on the dorsal surface of the posterior body. The present record confirms the presence of the genus in the subtropical waters of South America.     

Three species of Dendromonocotyle Hargis, 1955 (Monogenea: Monocotylidae) collected from Japanese rays

Systematic Parasitology - Eighteen species of Dendromonocotyle Hargis, 1955 (Monogenea: Monocotylidae) have so far been described from elasmobranchs worldwide. In this paper, two new species are...     

Morphology and development of the haptors among the Monocotylidae (Monogenea)

Monocotylid monogeneans inhabit a wide diversity of sites on their chondrichthyan hosts including the skin, gills, nasal fossae, urogenital system and coelom. The large variation in the morphology of the haptor appears to reflect this diversity in attachment sites. We demonstrate that the complexity of the haptor can be related to the habitat of the parasite. Generally, those parasites which live in habitats subject to strong water currents such as the gills and dorsal skin surface have more complex haptors than those in environments exposed to weaker or no water currents including the nasal fossae, urogenital system and body cavity. However, there can be considerable variation in haptoral components, even among congeners, living on the ‘gills’ of their hosts. The microhabitat was determined for Monocotyle helicophallus and M. spiremae, both from the gills of the pink whipray, Himantura fai, and M. corali from the gills of the cowtail ray, Pastinachus sephen. We demonstrate that differences in the morphology of the hamuli and the number and morphology of septal sclerites and marginal papillae among these species of Monocotyle can be related directly to their microhabitat. It also appears that different haptoral structures are important for attachment to the host at different stages in the development of the parasite, based on studies on the development and distribution of Neoheterocotyle rhinobatidis from the gills of the common shovelnose ray Rhinobatos typus. This revised version was published online in July 2006 with corrections to the Cover Date.     

A new species of Empruthotrema (Monogenea: Monocotylidae) from Pteromylaeus bovinus (Myliobatidae) from the Western Mediterranean

Empruthotrema chisholmae n. sp. is described from specimens recovered from a bull ray Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817) at the Oceanogràfic Aquarium in Valencia, Spain. The bull ray was caught in the Spanish Mediterranean (Puerto de Mazarrón, Murcia). The new species resembles 4 others of the same genus ( Empruthotrema dasyatidis Whittington and Kearn, 1992, Empruthotrema kearni Whittington, 1990, Empruthotrema stenophallus Chisholm and Whittington, 2005, and Empruthotrema tasmaniensis Chisholm and Whittington, 1999) in having a haptor with 13 marginal loculi, the posteriormost loculus single and medial. The new species can be distinguished from these other species of the genus by the morphology of the sclerotized male copulatory organ, which is the shortest described. The new species also differs from the other species by the following combination of features: haptor with 13 marginal loculi, the presence of eyespots, the absence of an accessory piece associated with the male copulatory organ, and a long egg appendage (more than 150 μm). Empruthotrema chisholmae is the first species of the genus reported from the Mediterranean.     

Molecular phylogeny of Potamotrygonocotyle (Monogenea,Monocotylidae) challenges the validity of some of its species

Fehlauer‐Ale, K. H. & Littlewood, D. T. J. (2011). Molecular phylogeny of Potamotrygonocotyle (Monogenea, Monocotylidae) challenges the validity of some of its species. —Zoologica Scripta, 40, 638–658. The marine‐derived stingrays Potamotrygonidae are the only chondrichthyans landlocked to freshwaters of Central and South America. The family includes approximately 22 described species organized in four genera widely distributed across the main Atlantic and Caribbean continental drainages. Investigations into the parasite fauna of potamotrygonids have mainly focused on cestodes, with a few studies addressing the biodiversity of monogeneans. Potamotrygonocotyle (Monogenea, Monocotylidae) is composed of 12 species, exclusively found in the gills of species of Potamotrygonidae. This study presents molecular phylogenetic analyses of this group of monogeneans distributed throughout La Plata and Amazonas basins, with the purpose of readdressing the phylogeny of Monocotylidae based on 28S rDNA sequences and of unravelling the phylogeny of its species using data from mitochondrial gene cytochrome c oxidase subunit I and nuclear gene internal transcribed spacer 1. The phylogenetic status of the five tested monocotylid subfamilies and most of their internal relationships are concordant with the results of a previous study, and the monophyletic status of Potamotrygonocotyle based on molecular data is corroborated for the first time. However, the placement of the genus within Monocotylidae is not resolved, as its sister‐group relationship with Neoheterocotyle and Troglocephalus is uncertain. Investigations into the relationships within Potamotrygonocotyle support the monophyletic status of nine nominal species and suggest the existence of cryptic lineages for the remaining three. Molecular analyses reveal distinct sister‐groups relationships in comparison with a previously published phylogeny for the genus based on morphological data. Finally, the surveys of this study expand the known distribution range of some members of Potamotrygonocotyle.     

Phylogenetic analysis of the Monocotylidae (Monogenea) inferred from 28S rDNA sequences

The current classification of the Monocotylidae (Monogenea) is based on a phylogeny generated from morphological characters. The present study tests the morphological phylogenetic hypothesis using molecular methods. Sequences from domains C2 and D1 and the partial domains C1 and D2 from the 28S rDNA gene for 26 species of monocotylids from six of the seven subfamilies were used. Trees were generated using maximum parsimony, neighbour joining and maximum likelihood algorithms. The maximum parsimony tree, with branches showing less than 70% bootstrap support collapsed, had a topology identical to that obtained using the maximum likelihood analysis. The neighbour joining tree, with branches showing less than 70% support collapsed, differed only in its placement of Heterocotyle capricornensis as the sister group to the Decacotylinae clade. The molecular tree largely supports the subfamilies established using morphological characters. Differences are primarily how the subfamilies are related to each other. The monophyly of the Calicotylinae and Merizocotylinae and their sister group relationship is supported by high bootstrap values in all three methods, but relationships within the Merizocotylinae are unclear. Merizocotyle is paraphyletic and our data suggest that Mycteronastes and Thaumatocotyle, which were synonymized with Merizocotyle after the morphological cladistic analysis, should perhaps be resurrected as valid genera. The monophyly of the Monocotylinae and Decacotylinae is also supported by high bootstrap values. The Decacotylinae, which was considered previously to be the sister group to the Calicotylinae plus Merizocotylinae, is grouped in an unresolved polychotomy with the Monocotylinae and members of the Heterocotylinae. According to our molecular data, the Heterocotylinae is paraphyletic. Molecular data support a sister group relationship between Troglocephalus rhinobatidis and Neoheterocotyle rhinobatidis to the exclusion of the other species of Neoheterocotyle and recognition of Troglocephalus renders Neoheterocotyle paraphyletic. We propose Troglocephalus incertae sedis. An updated classification and full species list of the Monocotylidae is provided.     

A new species of Neoheterocotyle Hargis, 1955 (Monogenea: Monocotylidae) from the gills of Pristis clavata Garman (Pristidae) from Darwin,Australia

Neoheterocotyle darwinensis n. sp. is described from between the secondary gill lamellae of the dwarf sawfish Pristis clavata Garman (Pristidae) collected at the mouth of Buffalo Creek near Darwin, Northern Territory, Australia. This is only the second monocotylid species to be described from northern Australia. N. darwinensis is distinguished from the other seven valid species in the genus by the morphology of the hamuli, the dorsal haptoral accessory sclerites and the male copulatory organ. The similarities between N. darwinensis and Nonacotyle pristis Ogawa, 1991 from the gills of the freshwater sawfish Pristis microdon Latham collected in Papua New Guinea are discussed.     

A new species of Thaumatocotyle (Monogenea: Monocotylidae) from Dasyatis sabina (Myliobatiformes: Dasyatidae) off the coast of South Carolina

Thaumatocotyle roumillati n. sp. is described from specimens collected in the nasal fossae of the Atlantic stingray, Dasyatis sabina (Lesueur) from the southeastern coast of the United States, off South Carolina. Thaumatocotyle roumillati is distinguished from congeners by the size and shape of its penis as well as the presence of a spinelike accessory piece associated with the penis.     

A redescription of Heterocotyle pastinacae Scott, 1904 (Monogenea: Monocotylidae) from Dasyatis pastinaca (Dasyatididae), with a neotype designation

Heterocotyle pastinacae Scott, 1904 is redescribed and a neotype is designated. H. pastinacae is most easily distinguished from other members of the genus by the elaborate arrangement of sclerotised spines in the vagina. The male copulatory organ also serves to differentiate it from other species in the genus. A possible function for the vaginal spines and unique form of the male copulatory organ is discussed. The use of head organ number as a generic character is considered questionable.     

Empruthotrema stenophallus n. sp. (Monogenea: Monocotylidae) from the nasal tissue of Dasyatis kuhlii (Dasyatidae) from Sabah, Borneo, Malaysia

Empruthotrema stenophallus n. sp. (Monogenea: Monocotylidae) is described from specimens from the nasal tissue of the blue-spotted maskray Dasyatis kuhlii (Muller and Henle, 1841) collected in shallow waters off Pulau Banggi and Pulau Mabul, Sabah, Borneo, Malaysia. This is the first monogenean species to be described from an elasmobranch collected from Sabah. E. stenophallus can be distinguished from the other 6 members of the genus by the morphology of the sclerotized male copulatory organ, which is narrow, short, and distally tapered. E. dasyatidis Whittington and Kearn, 1992, previously documented from the nasal tissue of several of elasmobranch species from Australia, is recorded from 8 host species distributed around Malaysian Borneo. These represent new host and locality records for this monocotylid. The difficulties in identifying species of Empruthotrema and the apparent lack of host specificity by some members of the genus are discussed.     

Empruthotrema dasyatidis n. sp. (Monogenea: Monocotylidae) from the olfactory sacs of Dasyatis fluviorum (Rajiformes: Dasyatidae) from Moreton Bay,Queensland

The monocotylid monogenean Empruthotrema dasyatidis n. sp. is reported from the olfactory sacs of the brown stingray, Dasyatis fluviorum Ogilby, 1908, from Moreton Bay, Queensland, Australia. This is the first record of Empruthotrema from the family Dasyatidae. E. dasyatidis n. sp. differs from other species of Empruthotrema by possessing eye pigment, which may be scattered, and by its small size. The generic diagnosis for Empruthotrema is amended.     

Two new species of Dendromonocotyle Hargis, 1955 (Monogenea: Monocotylidae) from the skin of Taeniura meyeni (Dasyatidae) and Aetobatus narinari (Myliobatidae) from aquaria in Queensland,Australia

Dendromonocotyle pipinna n. sp. (Monogenea: Monocotylidae) is described from the dorsal skin surface of Taeniura meyeni Müller & Henle from a public aquarium in Mooloolaba, Queensland, Australia. D. torosa n. sp. was found on the dorsal skin surface of a heavily infected specimen of Aetobatus narinari (Euphrasen) during a post-mortem at the Mooloolaba aquarium and on a specimen of A. narinari kept in an aquarium in Cairns. Both of these new Dendromonocotyle species are distinguished from each other and others in the genus by the morphology of the terminal papillary sclerite and the male copulatory organ.     

A Redescription of Calicotyle australis Johnston, 1934 (Monogenea: Monocotylidae) from the Type-host Trygonorrhina Fasciata (Rhinobatidae) off Adelaide, South Australia, Including Descriptions of Live and Silver Stained Larvae

Calicotyle australis Johnston, 1934 (Monogenea Monxocotylidae) is redescribed from the cloaca of the type-host, the southern fiddler ray Trygonorrhina fasciata (Rhinobatidae) off Adelaide, South Australia. Lobed glands joining the oötype are reported for the first time and may be characteristic of the genus. The presence of an appendix associated with the seminal vesicle in C. australis, previously reported as absent, is confirmed. The anatomy of the oncomiracidium of C. australis is described from observations of live larvae, and the number and distribution of ciliated epidermal cells and sensilla, revealed by silver staining larvae, is also described. Use of larval characters to distinguish between species of Calicotyle Diesing, 1850 and other closely related monocotylids is discussed.     

Myliocotyle pteromylaei gn. and sp. n. (Monogenea, Monocotylidae) gill parasite of Pteromylaeus bovinus (Euselachii, Myliobatidae) in Tunisia

Fifteen specimens of Pteromylaeus bovinus (Geoffroy St. Hilaire) from the Tunisian coast were examined for ectoparasites during 1996-1998. Myliocotyle pteromylaei gn. et sp. n. found on gills of twelve host specimens is described and illustrated. It differs from other Heterocotylinae mainly by the number and morphology of haptoral dorsal structures, arrangement and number of the anterior glands and morphology of the penis. M. pteromylaei, along with Heliocotyle kartasi, illustrates the originality of monocotylids gill parasites of Pteromylaeus bovinus.     

Three new species of Monocotyle (Monogenea: Monocotylidae) from the stingray, Himantura uarnak (Rajiformes: Dasyatidae) from the Great Barrier Reef: phylogenetic reconstruction, systematics and emended diagnoses

Three new species of Monocotyle were found on the gills of the coachwhip stingray, Himantura uarnak (Rajiformes: Dasyatidae) collected at Heron Island, Great Barrier Reef, Australia (23 degrees 27' S, 151 degrees 55 'E). Monocotyle helicophallus new species, Monocotyle multiparous new species and Monocotyle spiremae new species all have a single testis and are distinguished from other described Monocotyle species by size of body and hamulus and number of coils of the sclerotized male copulatory organ (21-22, three to four and 29-42, respectively). Monocotyle helicophallus new species is characterized by several muscular genital papillae, one of which is traversed by the ejaculatory duct; M. spiremae new species is distinguished by a sclerotized accessory structure associated with the distal end of the male copulatory organ, a vaginal sclerite and a conspicuous spherical, ejaculatory bulb; M. multiparous new species is distinguished by a large number of retained, thin-shelled eggs, many of which contain a fully developed oncomiracidium. A phylogenetic analysis of the 14 described species of Monocotyle utilizing 13 characters (11 binary and two multistate) produced the most parsimonious cladogram involving 18 steps with a consistency index of 0.78, two homoplasies and four unresolved polychotomies. Emended diagnoses of the Monocotylinae and Monocotyle are provided.     

Three new species of Merizocotyle Cerfontaine, 1894 (Monogenea: Monocotylidae) from the nasal tissues of dasyatid rays collected off Malaysian and Indonesian Borneo

Three new species of Merizocotyle Cerfontaine, 1894 (Monogenea: Monocotylidae) are described from the nasal tissues of stingrays collected off Borneo. Merizocotyle macrostrobus n. sp. is described from the dwarf whipray Himantura walga (Müller & Henle) collected in shallow waters off Sematan, Sarawak, Malaysia. This species can be distinguished from the other members of the genus by the morphology of the sclerotised male copulatory organ, which is long with many twists and loops. The vaginae of this species are also long and looped. Merizocotyle papillae n. sp. is described from the roughnose stingray Pastinachus solocirostris Last, Manjaji & Yearsley collected off Sematan and Mukah, Sarawak, Malaysia. It is distinguished from the other species of Merizocotyle by the morphology of the male copulatory organ, which is a sclerotised tube that expands slightly and then tapers at the distal end, and by the presence of papillae on the dorsal edge of the haptor. Merizocotyle rhadinopeos n. sp. is described from the whitenose whip ray Himantura uarnacoides (Bleeker) collected off Manggar, East Kalimantan, Indonesia. It can be differentiated by the male copulatory organ, which is a short, narrow, curved, sclerotised tube tapering distally, and the path of the ovary, which runs anteriorly to the base of the o?type. We also provide details of new host and/or locality records for M. australensis (Beverley-Burton & Williams, 1989) Chisholm, Wheeler & Beverley-Burton, 1995, M. icopae Beverley-Burton & Williams, 1989 and M. pseudodasybatis (Hargis, 1955) Chisholm, Wheeler & Beverley-Burton, 1995.     

Calicotyle urolophi n. sp. (Monogenea: Monocotylidae) from stingarees,Urolophus spp. (Elasmobranchii: Urolophidae) taken in coastal waters of Southern Australia

Calicotyle urolophi n. sp. is proposed for calicotylines found in the cloaca of three stingaree species, Urolophus cruciatus, U. bucculentus and U. paucimaculatus, collected off the southeastern coast of Tasmania. Variations in the soft body parts were observed between specimens taken from U. cruciatus and U. bucculentus but were not considered sufficient for separation into two species. C. urolophi is differentiated from other Calicotyle spp. found in the South Pacific by the configuration of the tubular male copulatory organ, the structure of the intestinal caeca and the arrangement of the vaginae. Amended diagnoses for the subfamily Calicotylinae and the genus Calicotyle are provided.