Claude Vaucher

Révision des cestodes (Monticelliidae) décrits par Woodland (1934) chez Brachyplatystoma filamentosum avec redéfinition des genres Endorchis Woodland, 1934 et Nomimoscolex Woodland, 1934

In 1934, Woodland described three new species of proteocephalidean tapeworms (Monticelliidae) from the Amazonian siluriform fish Brachyplatystoma filamentosum: Endorchis piraeeba (type-species), Nomimoscolex piraeeba (type-species) and Amphoteromorphus piraeeba. Examination of Woodlands type-material and its comparison with newly collected specimens from the same host close to the type-localities revealed inaccuracies in Woodlands diagnoses of these taxa. The main problems concern the scolex of E. piraeeba, the gravid proglottis of N. piraeeba and aspects of the anatomy of A. piraeeba. In our revision, we establish that: (1) the scolex assigned by Woodland to E. piraeeba belongs to N. piraeeba, and the actual scolex of E. piraeeba is characterised by bi-lobed suckers; (2) the gravid proglottis figured by Woodland does not belong to N. piraeeba, differing in particular, in the presence of paramuscular vitelline follicles and the cirrus-pouch length/proglottis width ratio; and (3) the cross-section assigned by Woodland to A. piraeeba belongs to N. piraeeba.This study enabled the redescription of all three taxa and the presentation of new diagnoses for the genera Nomimoscolex and Endorchis. The latter genus is considered valid. A lectotype is designated for N. piraeeba. In addition, members of the genus Nomimoscolex were revised and seven of 16 species were transferred to other genera or considered to be species inquirendae. N. magna Rego, Santos & Silva, 1974 becomes, in part, Monticellia magna n. comb. and, in part, Proteocephalus sp. N. piracatinga Woodland, 1935 becomes M. amazonica nom. nov. (to avoid homonyny with M. piracatinga Woodland, 1935). Proteocephalus chubbi Pavanelli & Takemoto, 1995 becomes N. chubbi (Pavanelli & Takemoto, 1995) n. comb. N. pirarara (Woodland, 1935) becomes P. pirarara n. comb. and N. woodlandi (Rego, 1984) becomes P. hemioliopteri nom. nov. (to avoid homonymy with P. woodlandi Moghe, 1926). N. pimelodi Gil de Pertierra, 1995 becomes P. pimelodi n. comb. nov. N. arandasregoi is considered a species inquirendae. N. alovarius is not classified. N. dorad is considered a synonym of N. piraeeba. In the light of recent ultrastructural data, the spines on N. piraeeba are considered as true microtriches. The following species are considered members of the genus Nomimoscolex: N. admonticellia, N. chubbi, N. lenha, N. lopesi, N. matogrossensis, N. microacetabula, N. piraeeba, N. sudobim and N. touzeti.A. peniculus Diesing of Woodland (1933) is considered conspecific with Amphoteromorphus piraeeba Woodland, 1934.In this study, we point out the importance of careful comparative morphological studies and taxonomic work. In the present case, the revision of the original material, without the study of new specimens, would have been inadequate to accurately define specific structural attributes as the basis for allocation of species at the generic level.

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.

Nomimoscolex suspectus n. sp. (Eucestoda: Proteocephalidea: Zygobothriinae) with morphological and molecular phylogenetic analyses of the genus.

We describe a new species of Nomimoscolex from the Amazon siluriform fishes Brachyplatystoma filamentosum, B. flavicans and B. vaillanti. It differs from N. piraeeba in a lower mean number of testes, the paramuscular position of the vitelline follicles, the ovarian width/proglottis width ratio and the cirrus-pouch length/proglottis width ratio. Protein electrophoresis assays performed for 25 enzymatic systems showed that specimens of N. suspectus n. sp. from the three host species form a homogenous population which was genetically isolated from N. piraeeba and N. dorad. Moreover, the latter two species, synonymised by Rego (1991) because of their close morphological similarity, could be separated at eight loci. We thus restore N. dorad as a valid species. We finally examined the composition of the genus Nomimoscolex using DNA sequences from the 5.8S rRNA, ITS-2 and 28S rRNA nuclear ribosomal genes and a matrix of 24 morphological characters. Phylogenetic relationships were inferred for nine species of the genus, five members of other monticelliid genera and two outgroup species. The results of the phylogenetic analyses performed on morphological and molecular characters converged with those from allozyme studies and showed that N. suspectus, N. piraeeba and N. dorad clustered in a distinct clade that excluded other members of the genus. We therefore recognised them as an aggregate of species to reflect an isolation supported by both morphological and genetic data. Because relationships among the remaining Nomimoscolex representatives and other genera were generally poorly resolved, regardless of the database analysed, no action was taken to reorganise them into alternative groupings.

Etude morpho-anatomique et génétique de deux nouveaux Proteocephalus Weinland, 1858 (Cestoda: Proteocephalidae) parasites de Platydoras costatus (L.), poisson siluriforme du Paraguay

The cat-fish Platydoras costatus (L.) is abundantly parasitised by the cestode genus Proteocephalus in Paraguay, previously unrecorded from this host. Morpho-metrical studies suggest the presence of two species, Proteocephalus soniae n. sp. and P. renaudi n. sp. They differ in the scolex, the distribution of the testes, the mean number of testes and uterine diverticula, the presence or absence of a vaginal sphincter, and the shape of the eggs and their envelopes. A single specimen, representing a possible third taxon, is morphologically similar to P. renaudi. Data from protein electrophoresis on amidon gel confirm the morpho-metrical conclusions. Of the 13 enzymes investigated, ACP, AAT, GPI and MDH have alleles of different electrophoretic mobilities in the three taxa. Only two alleles are distinguishable on locus HK. There is no evidence of heterozygotes in the tested systems. The specific status of the examined taxa is therefore confirmed. More material of the third species is required for establishing a species definition. P. renaudi has following unique anatomical features: the egg bears an enormous external envelope and an elongate embryophore with a unilateral appendix; the vitelline glands are paramuscular; and the eggs, laid in packets, are evacuated in an unusual way.The establishment of species based on protein electrophoresis allows a critical examination of the validity of anatomical characters usually used for taxonomic purpose. Good specific characters are the presence or absence of an apical organ and a vaginal sphincter and the relatively constant ratio between ovary width and the width of mature proglottids. The number of testes and uterine diverticula, both frequently used in species diagnoses, show variations which are often considerable and are, therefore, less unequivocal. The coefficients of variation observed calculating the mean numbers of testes can be high and reach up to 28%. This variation is itself a specific character in our opinion.

Morphological and genetic differentiation of Rodentolepis straminea (Goeze, 1752) and Rodentolepis microstoma (Dujardin, 1845) (Hymenolepididae)

Abstract. The two related species, Rodentolepis straminea (Goeze, 1782) and Rodentolepis microstoma (Dujardin, 1845) (Cestoda, Hymenolepididae), both parasites of rodents, were compared morphologically and electrophoretically. Adult worms were isolated from three wild rodent species of the family Muridae (Apodemus flavicollis, Apodemus sylvaticus, and Mus musculus) from three different sites in Spain and France. Although these two species were strikingly similar in morphological appearance, some of the morphological and metrical features analysed (scolex, mature segments and eggs) can be used for differentiation. Fixed allelic differences were found. Of the ten enzymes detected by starch-gel electrophoresis, six (AAT, AK, GPI, MDH, NP, PGM) showed characteristic isoenzyme profiles in each species. Only in MPI, PEPC, PEPD, and ME enzyme loci were no differences found. The study revealed that the two taxa can be clearly differentiated.

Revision of the genus Vampirolepis Spasskij, 1954 (Cestoda: Hymenolepididae)

The genus Vampirolepis Spasskij, 1954 is re-defined on the basis of the original description and the first detailed redescription by Andreiko et al. (1969). A restricted definitions is proposed, the main features being the arrangement of testicles on a straight line snd numerous hooks of fraternoid shape. Other important characters are the strobila with numerous proglottids, the cirrus pouch of moderate size and the cirrus, smooth or armed with minute spines. Formerly included Hymenolepidid cestodes with reduced strobila, particularly long cirrus pouch and different arrangement of gonads do not belong to Vampirolepis. Members of Vampirolepis in the restricted sense show a cosmopolitan repartition and parasitize only bats. The author does not accept the synonymy of Rodentolepis Spasskiji, 1954 with Vampirolepis. A tentative list of the species belonging to the genus is proposed.

Nomimoscolex touzeti n. sp. (Cestoda), a parasite of ceratophrys cornuta (L.): first record of a monticellidae in an amphibian host

Nomimoscolex touzeti n. sp. is described from one Ceratophrys cornuta (L.) caught in Amazonian Ecuador. Its taxonomic relationships to the others species are discussed. This new species is characterized by a cortical position of vitellaria; by the presence in the uteroduct of conglomerates of 20-40 eggs; by a weak ovary width/proglottis width ratio; by ventral excretory canals anastomosed; by a powerful vaginal sphincter and by a long cirrus. N. touzeti is the first record of Monticellidae in an amphibian host.

Crassicutis intermedius (Szidat, 1954) n. comb. and Procaudotestis uruguayensis Szidat, 1954 (Digenea: Homalometridae) from siluriform fishes in Paraguay

The following two species are redescribed from Paraguayan freshwater siluriform fishes: Crassicutis [=Eocreadium] intermedius (Szidat, 1954) n. comb. from Cochliodon cochliodon, Hypostomus piratatu, H. commersoni, H. boulengeri and Hoplosternum littorale; and Procaudotestis uruguayensis Szidat, 1954 from Loricaria sp. The redescription of the terminal genitalia of both species indicates that they should be considered members of the family Homalometridae.

A new genus of Dilepididae (Cestoda) of the yellowbill Ceuthmochares aereus (Cuculidae) from the Ivory Coast.

Bonaia africana n. gen., n. sp. (Cestoda: Dilepididae) has been found in Ceuthmochares aereus (Aves: Cuculidae) in the Ivory Coast (West Africa). This new tapeworm is mainly characterized by its unusual rostellar hooks that are implanted irregularly and which present a variable form and length in the same rostellum. The differential diagnosis, particularly in comparison with the closely related genera Liga and Amoebotaenia, is presented: Liga possesses an atrial bundle of setae and Amoebotaenia 1 row of well built hooks with a typical blade. It is assumed that the unusual disposition of the rostellar hooks described here could be a transitional form between the 1- and 2-row patterns or a degenerate derivative of a regular arrangement.

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.