Guerrerostrongylus marginalis n. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana

Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp

Gastrointestinal Helminths of Two Species of Mouse Opossums (\u3ci\u3eMarmosa demerarae\u3c/i\u3e and \u3ci\u3eMarmosa murina\u3c/i\u3e) from French Guiana

The woolly mouse opossum Marmosa demerarae and the murine opossum, Marmosa murina, occur in sympatry across most of their range; however, they are not syntopic in that M. demerarae is more abundant in the canopy of primary and secondary forest, while M. murina is scansorial and appears to be more abundant in lower forest strata. We herein present a survey and comparison of the helminths occurring in these 2 species in French Guiana based on examinations of 18 individuals of M. murina and 21 individuals of M. demerarae. At the level of the component community, species richness was established at 12 for M. demerarae and 14 for M. murina; the nematodes Pterygodermatites (Paucipectines) elegans and Aspidodera raillieti were established as the most abundant and prevalent species in M. demerarae and M. murina, respectively. Infracommunities in both species had an average species richness of 3.7 and 3.8, respectively. Both species share 12 species of parasites, yet Phaneropsolus philanderi, Pterygodermatites (Paucipectines) elegans, Travassostrongylus paraquintus, Trichuris reesali, and Spirura trinitatis were significantly more frequent in M. demerarae. Infections also included Mathevotaenia bivittata, an unidentified anoplocephalid, and Viannaia venezuelensis, all 3 species of which were more frequent in M. murina

Molecular phylogeny of the Praomys complex (Rodentia : Murinae) : a study based on DNA/DNA hybridization experiments

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Mitochondrial simple sequenze repeats and 12s – rRNA gene reveal two distinct lineages of Crocidura russula (Mammalia, Sorcidae)

A short segment (135 bp) of the control region and a partial sequence (394 bp) of the 12S-rRNA gene in the mitochondrial DNA of Crocidura russula were analyzed in order to test a previous hypothesis regarding the presence of a gene flow disruption in northern Africa. This breakpoint would have separated northeast-African C. russula populations from the European (plus the northwest-African) populations. The analysis was carried out on specimens from Tunisia (C. r. cf agilis), Sardinia (C. r. ichnusae), and Pantelleria (C. r. cossyrensis), and on C. r. russula from Spain and Belgium. Two C. russula lineages were identified; they both shared R2 tandem repeated motifs of the same length (12 bp), but not the same primary structure. These simple sequence repeats were present in 12–23 copies in the right domain of the control region. Within the northeast-African populations, a polymorphism of repeat variants, not yet found in Europe, was recorded. A neighbor-join tree, which was built by sequences of the conserved 12S-rRNA gene, separated the two sister groups; it permitted us to date a divergence time of 0.5Myr. Our data discriminated two different mitochondrial lineages in accordance with the previous morphological and karyological data. Ecoclimatic barriers formed during the Middle Pleistocene broke the range of ancestral species in the Eastern Algeria (Kabile Mountains), leading to two genetically separate and modern lineages. The northeast-African lineage can today be located in Tunisia, Pantelleria, and Sardinia. The northwest- African lineage (Morocco and West Algeria), reaching Spain by anthropogenic introduction, spread over north Europe in modern times. The Palaearctic C. russula species is monophyletic, but a taxonomical revision (ie, to provide a full species rank for the northeast taxa and to put in synonymy some insular taxa) is required