Polystoma cuvieri n. sp. (Monogenea: Polystomatidae), a parasite of the urinary bladder of the leptodactylid frog Physalaemus cuvieri in Paraguay

A new species of polystomatid monogenean, Polystoma cuvieri, is described from the urinary bladder of the leptodactylid frog Physalaemus cuvieri Fitzinger in Paraguay. This new species possesses a reticulated intestine and hamuli of about 350 microns long. The closest species is Polystoma napoensis Vaucher, 1987, described from Osteocephalus spp. in Ecuador. The Paraguayan material is distinguished by the blade size of the hamuli. The hamuli blades appear to be useful in Polystoma systematics.     

Polystomatidae (Monogenea) of African Anura: Polystoma dawiekoki n. sp. parasitic in Ptychadena anchietae (Bocage)

Polystoma dawiekoki n. sp. is described as a new species of the Polystomatidae parasitic in the urinary bladder of the plain grass frog Ptychadena anchietae. This parasite was collected at Mkuze town and Mkuze Game Reserve in northern Kwazulu-Natal Province, in the Kruger National Park in Mpumalanga Province, South Africa, and at Bulwa in Tanga Province, East Usambara Mountains, Tanzania. It is distinguished from other African Polystoma species by a combination of characters, including the body size, size and shape of marginal hooklets and the haptor length to body length ratio. The presence of adult, as well as subadult, parasites in the same individuals, as is known for Eupolystoma, represents a significant evolutionary departure from the pattern of transmission typical of Polystoma in most of the other anuran hosts.     

Polystoma knoffi n. sp. and Polystoma travassosi n. sp. (Monogenea: Polystomatidae): naming museum-archived specimens from Brazil

Systematic Parasitology - In 1978, Kohn and co-workers deposited several polystome (Monogenea) specimens infecting several Brazilian anurans [Trachycephalus mesophaeus (Hensel), T. nigromaculatus...     

Polystomatidae (Monogenea) of southern African Anura: Polystoma claudecombesi n. sp. parasitic in Rana angolensis Bocage

Polystoma claudecombesi is described as a new species of the Polystomatidae (Monogenea) parasitic in the urinary bladder of the anuran host Rana angolensis. This parasite was collected at three localities in South Africa, namely Vernon Crookes Nature Reserve in Natal province, Witsieshoek Mountain Resort in the north-eastern Orange Free State and Bovenste Oog in the province of Transvaal. It is the largest African polystome described to date. Prevalence at Vernon Crookes Nature Reserve was 4.0% and 2.7% in two successive years, with a mean intensity of 1.0 (n=25 and 36, respectively). One of the two R. angolensis from Witsieshoek was infected with 5 parasites. The diversity and distribution of southern African polystomes is also discussed.     

Polystoma nacialtuneli n. sp. (Monogenea: Polystomatidae) from the eastern spadefoot, Pelobates syriacus (Pelobatidae) in Turkey

Polystoma nacialtuneli n. sp. is described from the urinary bladder of the eastern spadefoot, Pelobates syriacus from Turkey. This is the fifth polystome species known from Turkey and the third species in Pelobates. We show that this new parasite species can be distinguished from other polystome species in the area by a combination of characteristics, including parasite size and the shape and size of the hamuli. Polystoma pelobatis from Pelobates cultripes has a pair of well-developed hamuli, while P. fuscus from Pe. fuscus characteristically has a pair of underdeveloped hamuli barely larger than the marginal hooklets. Polystoma nacialtuneli n. sp. has well-developed hamuli that vary significantly in shape. Phylogenetic relationships of P. nacialtuneli n. sp. within Polystoma, supplemented with molecular divergences estimated from internal transcribed spacer 1 (ITS1) sequences, indicate that they are well separated from their closest relatives, i.e. P. fuscus and P. pelobatis from Pe. fuscus and Pe. cultripes, respectively.     

Polystomatidae (Monogenea) of Anura in southern Africa: Polystoma testimagna n. sp. parasitic in Strongylopus f. fasciatus (Smith, 1849)

Polystoma testimagna n. sp. is described as a new species of the Polystomatidae, parasitic in the urinary bladder of the striped stream frog Strongylopus f. fasciatus collected in the Vernon Crookes Nature Reserve, Natal, South Africa. Parasite prevalence was found to be 50.0% and 27.7% in two successive years, and the mean intensity was 1.5 and 1.6, respectively. The species occurs together with another Polystoma species in the same water body and within one kilometre from a third species. Aspects of host specificity are discussed and data on the ecology and distribution of the host presented.     

Heteromorphic Z and W sex chromosomes in Physalaemus ephippifer (Steindachner, 1864) (Anura, Leiuperidae)

Heteromorphisms between sex chromosomes are rarely found in anurans and sex chromosome differentiation is considered to be a set of recent recurrent events in the evolutionary history of this group. This paper describes for the first time heteromorphic sex chromosomes Z and W in the leiuperid genus Physalaemus. They were found in P. ephippifer, a species of the P. cuvieri group, and corresponded to the eighth pair of its karyotype. The W chromosome differed from the Z chromosome by the presence of an additional segment in the short arm, composed of a distal NOR and an adjacent terminal DAPI-positive C-band. The identification of this sex chromosome pair may help in future investigations into the sex determining genes in the genus Physalaemus.     

Polystoma luohetong n. sp. (Monogenea: Polystomatidae) from Rana chaochiaoensis Liu (Amphibia: Ranidae) in China

Systematic Parasitology - Polystoma chaochiaoensis from the urinary bladder of the chaochiao frog Rana chaochiaoensis Liu was briefly described in a symposium abstract and presented at the Third...     

Polystoma macrocnemis n. sp. (Monogenea: Polystomatidae) from the Iranian longlegged wood frog Rana macrocnemis (Ranidae) in Turkey

Polystoma macrocnemis n. sp. (Polystomatidae) is described from the urinary bladder of Rana macrocnemis (Ranidae) in Turkey. Its general morphology is similar to that of other members of the genus, but it is distinguished from closely related species by numerical parameters of the hamuli and also by its host species and geographical range.     

Polystoma fuscus n. sp. (Polystomatidae) from the common spadefoot Pelobates fuscus (Pelobatidae) in Bulgaria

Polystoma fuscus n. sp. (Polystomatidae, Polystomatinae) is described from the urinary bladder of Pelobates fuscus (Pelobatidae) in Bulgaria. Its general morphology is similar to that of other members of the genus but distinguished from them by the underdeveloped hamuli similar to the larval hamular primordia. The new species is also differentiated from the members of the genera of the subfamily Polystomatinae described without hamuli.     

Origin and evolution of African Polystoma (Monogenea: Polystomatidae) assessed by molecular methods

Among Polystomatidae (Monogenea), the genus Polystoma, which mainly infests neobatrachian hosts, is the most diverse and occurs principally in Africa, from where half the species have been reported. Previous molecular phylogenetic studies have shown that this genus originated in South America, and later colonised Eurasia and Africa. No mention was made on dispersal corridors between Europe and Africa or of the origin of the African Polystoma radiation. Therefore, a molecular phylogeny was inferred from ITS1 sequences of 21 taxa comprising two species from America, seven representatives from Europe and 12 from Africa. The topology of the phylogenetic tree reveals that a single event of colonisation took place from Europe to Africa and that the putative host carrying along the ancestral polystome is to be found among ancestral pelobatids. Percentage divergences estimates suggest that some presumably distinct vesicular species in unrelated South African anurans and some neotenic forms found in several distinct hosts in Ivory Coast, could, in fact, belong to two single polystome species parasitising divergent hosts. Two main factors are identified that may explain the diversity of African polystomes: (i), we propose that following some degree of generalism, at least during the juvenile stages of both hosts and parasites, distinctive larval behaviour of polystomes engenders isolation between parasite populations that precludes sympatric speciations; (ii), cospeciation events between Ptychadena hosts and their parasites are another factor of diversification of Polystoma on the African continent. Finally, we discuss the systematic status of the Madagascan parasite Metapolystoma, as well as the colonisation of Madagascar by the host Ptychadena mascareniensis.     

Polystomatidae (Monogenea) of Southern African Anura: Eupolystoma vanasi n. sp. parasitic in Schismaderma carens (Smith)

Eupolystoma vanasi is described as a new species of the Polystomatidae parasitic in the urinary bladder of Schismaderma carens in Northern Province and KwaZulu-Natal Province, South Africa. This is the third Eupolystoma species described from Africa and the first polystomatid from Schismaderma, an anuran genus that is primitive with respect to the other African bufonids in which Eupolystoma has been recorded. The species is distinguished by body size (this is the largest Eupolystoma known; mean length of adults 6 mm), by genital spine number (4 in comparison with 6-9 in other species), marginal hooklet length (greater than in other African species), and by the small size of the ovary and testis. In a sample of 27 toads, 37% were infected with up to 130 parasites per host (mean intensity 37). Worm burdens of this magnitude are exceptional amongst polystomatids in general but are characteristic of Eupolystoma, where there may be repeated re-infection of adult hosts and, uniquely, a direct, internal cycle of auto-infection.     

Historical biogeography of amphibian parasites, genus Polystoma (Monogenea: Polystomatidae)

Aim  The present-day geographical distribution of parasites with a direct biological life cycle is guided mostly by the past dispersal and vicariance events that have affected their hosts. The Amphibia– Polystoma association (which satisfies these criteria) also exhibits original traits, such as host specificity and world-wide distribution. This biological model was thus chosen to investigate the common historical biogeography of its widespread representatives.
Location  North and South America, Eurasia and Africa.
Methods  We investigated the phylogeny of 12 species of neobatrachian parasites sampled from North and South America, Eurasia and Africa. Hosts belonged mostly to hyloids and ranoids of families Bufonidae, Hylidae, Leptodactylidae, Ranidae and Hyperoliidae. Phylogenetic reconstructions were inferred from maximum likelihood and maximum parsimony analyses from complete ITS1 sequences.
Results  The group of American species appeared paraphyletic with one species at the base of a Eurafrican clade, within which two lineages were seen: one composed of only Eurasian species, and the other of European and African species, with the two European species basal to an African clade.
Main conclusions  The route of Polystoma evolution is deduced from the phylogenetic tree and discussed in the light of host evolution. We conclude that Polystoma originated in South America on hyloids, after the separation of South America from Africa. The genus must have colonized North America in Palaeocene times and Eurasia by the mid-Cainozoic, taking advantage of the dispersal of either ancestral bufonids or hylids. Africa, however, appears to have been colonized more recently, during the Messinian period.     

Gyrodactylus gemini n. sp. (Monogenea: Gyrodactylidae), a parasite of Semaprochilodus taeniurus (Steindachner) from the Venezuelan Amazon

Gyrodactylus gemini n. sp. (Monogenea, Gyrodactylidae) is described from the surface of the body and fins of the fish Semaprochilodus taeniurus (Steindachner) imported into Britain from the Venezuelan Amazon. The new species differs from other species of the genus, including those described from South and Central America, by having: (i) stout hamuli with straight shafts and diverging roots; (ii) marginal hooks with the sickle length larger than the width; (iii) a dorsal bar without a medial constriction; (iv) a rectangular ventral bar with short processes; (v) a triangular ventral bar membrane; and, most obviously, (vi) at least two generations which can develop two embryos simultaneously. This is the first known species of the genus Gyrodactylus from the Venezuelan Amazon and the first record of the subgenus Gyrodactylus (Gyrodactylus) from South America.     

A new species of Polystoma (Monogenea: Polystomatidae) parasitic in Hyperolius marmoratus (Anura: Hyperoliidae) in South Africa

Polystoma marmorati n. sp. is described as a new polystomatid species parasitic in the urinary bladder of the painted reed frog Hyperolius marmoratus marmoratus collected in southern Natal, South Africa. Parasite prevalence varied from 14.5 to 47.4% and the mean intensity from 1.0 to 1.1. The hamuli of the new species have a characteristic, partly fragmented appearance, a feature also seen in Polystoma batchvarivi, the only other polystome described from a species of the genus Hyperolius. The similarity between the two species, in spite of their geographical separation, is commented upon.     

Neopolystoma fentoni n. sp. (Monogenea: Polystomatidae) a parasite of the conjunctival sac of freshwater turtles in Costa Rica

Neopolystoma fentoni n. sp. is described from the conjunctival sac of Kinosternon leucostomum (Duméril, Bibron, and Duméril 1851) and Rhinoclemmys pulcherrima (Gray 1855) from the Guanacaste Conservation Area in Costa Rica. The new species differs from all other species of Neopolystoma, except N. elizabethae Platt 2000 in possessing a circle of eight genital spines that are recurved and possess a crescent-shaped base. N. fentoni n. sp. differs from N. elizabethae in lacking cecal diverticula and in a number of morphometric criteria.     

Sundapolystoma chalconotae n. g., n. sp. (Monogenea: Polystomatidae) from Rana chalconota (Schlegel) of Peninsular Malaysia

Sundapolystoma chalconotae. n. g., n. sp. (Polystomatidae, Polystomatinae) is proposed for a new polystomatid from the urinary bladder of Rana chalconota (Schlegel) in Peninsular Malaysia. This is the first species of polystomatid to be described from the amphibians of Peninsular Malaysia and the second for the Southeast Asian region. This new genus, as exemplified by S. chalconotae, differs from other polystomatids, and in particular Parapolystoma Ozaki, 1935 (P. bulliense (Johnston, 1912) Ozaki, 1935 and P. johnstoni Pichelin, 1995), in having a tubular uterus and a single diffuse testis. P. crooki Vande Vusse, 1976 is similar to S. chalconotae in having a similar type of uterus and testis, and is re-assigned as Sundapolystoma crooki (Vande Vusse, 1976) n. comb. S. chalconotae differs from S. crooki in having anchors with a longer outer root rather than a longer inner root and 7-8 genital spines compared to 9-13 in S. crooki.     

Hox genes from the Polystomatidae (Platyhelminthes, Monogenea)

Hox genes form a multigenic family that play a fundamental role during the early stages of development. They are organised in a single cluster and share a 60 amino acid conserved sequence that corresponds to the DNA binding domain, i.e. the homeodomain. Sequence conservation in this region has allowed investigators to explore Hox diversity in the metazoan lineages. Within parasitic flatworms only homeobox sequences of parasite species from the Cestoda and Digenea have been reported. In the present study we surveyed species of the Polyopisthocotylea (Monogenea) in order to clarify Hox identification and diversification processes in the neodermatan lineage. From cloning of degenerative PCR products of the central region of the homeobox, we report one ParaHox and 25 new Hox sequences from 10 species of the Polystomatidae and one species of the Diclidophoridae, which extend Hox gene diversity from 46 to 72 within Neodermata. Hox sequences from the Polyopisthocotylea were annotated and classified from sequence alignments and Bayesian inferences of 178 Hox, ParaHox and related gene families recovered from all available parasitic platyhelminths and other bilaterian taxa. Our results are discussed in the light of the recent Hox evolutionary schemes. They may provide new perspectives to study the transition from turbellarians to parasitic flatworms with complex life-cycles and outline the first steps for evolutionary developmental biological approaches within platyhelminth parasites.