Redescription of Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda: Heligmosomidae) from a Chinese rodent, Apodemus peninsulae (Rodentia: Muridae); with comments on Heligmosomoides polygyrus polygyrus (Dujardin, 1845) and related species in China and Japan.

Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda, Heligmosomoidea) is redescribed from Apodemus peninsulae from Rangtang, Sichuan, China. A morphological review of the Heligmosomoides spp. belonging to the "polygyrus line" proposed by Asakawa (1988) is made using new characters. This enabled us to distinguish two subspecies in Mus musculus (Heligmosomoides polygyrus bakeri from Japan and H. p. polygyrus from China) and two valid species in Apodemus spp. (H. neopolygyrus from Japan (in A. peninsulae) and from China (in A. agrarius) and H. asakawae from China (in A. uralensis)). Three parasite species of A. agrarius and A. peninsulae, previously identified by Asakawa et al. (1993) as H. neopolygyrus, are considered to be Heligmosomoides incertae sedis. This is the first report of H. neopolygyrus in A. peninsulae from China.

The caudal bursa in the Heligmonellidae (Nematoda: Trichostrongylina). Characterization and hypothesis on its evolution.

The different patterns of the caudal bursa of the Heligmonellidae (Nematoda) are redefined, taking into account the grouping of rays 2-6 and the sequence of origin of these rays from their common trunk. The type of symmetry of the caudal bursa is also redefined. The following patterns were observed and characterized: the basic patterns: types 2-3, 2-2-1, 1-3-1 and 1-4 and the intermediary patterns: type 2-3 tending to type 2-2-1, type 2-2-1 tending to type 1-3-1, type 1-3-1 tending to type 1-4 and type 2-2-1 tending to type 1-4. An evolutionary interpretation of the patterns is attempted and seems to follow the direction: 2-3 to 2-2-1 to 1-3-1 to 1-4. Seven atypical patterns are described. The caudal bursae were classified based on their symmetry: subsymmetrical, dissymmetrical and asymmetrical. Independently of the type of symmetry, the two latero-ventral lobes may have the same or different patterns. The type of symmetry, the ratio between the two latero-ventral lobes and a characteristic pattern were utilized to characterize the caudal bursae at the level of the genus and the subfamily. The combination of the right/left ratio and the type of symmetry gives heterogeneous results, with no real association between these characters. The most conspicuous asymmetries and dissymmetries were found among the Nippostrongylinae. The most frequent pattern in the Heligmonellidae is the basic type 2-2-1; types 1-3-1 and 1-4 are less frequent but are characteristic of several genera; type 1-4 is absent from the Heligmonellinae. Whatever the pattern, in the Heligmonellidae rays 4 and 5 are the last to diverge from the common trunk of rays 2-6.

Additional morphometrical data on some Heligmonellidae (Nematoda: Trichostrongylina) parasitic in Neotropical rodents (Cricetidae).

Some additional morphological and metrical data are provided, particularly on the synlophe of the following species: Hassalstrongylus dessetae Pinto, 1978, Stilestrongylus eta (Travassos, 1937), Stilestrongylus manni Denké & Murúa, 1977 and Stilestrongylus valdivianus Durette-Desset & Murúa, 1979, based on type and voucher material deposited in Brazilian and French collections. Heligmonoides crassidorsualis Franco, 1967 is considered as a Nippostrongylinae incertae sedis: its synlophe not being known it is impossible to report the species to a given genus. However, it is unlikely that the species belong to the genus Heligmonoides Baylis, 1928, present only in commensal Murinae from the Old World. Heligmonoides mirzai Smales, 2009, is also regarded, temporarily, as a Nippostrongylinae incertae sedis.

Discovery of new Ohbayashinema spp. (Nematoda: Heligmosomoidea) in Ochotona princeps and Ochotona cansus (Lagomorpha: Ochotonidae) from western North America and Central Asia, with considerations of historical biogeography.

Three new species of Ohbayashinema (Nematoda, Heligmosomoidea) are described from localities in western North America and central Asia. Two of these species, Ohbayashinema nearctica n. sp. and Ohbayashinema aspeira n. sp., are parasitic in American pika, Ochotona princeps. Ohbayashinema nearctica is differentiated from the 5 known species of the genus parasitic in Ochotonidae from the Old World by very long spicules and an oblique axis of orientation for the ridges composing the synlophe. Ohbayashinema aspeira, described only from females, is similar to Oh. nearctica based on the number of cuticular ridges at the mid-body. It is mainly differentiated by an uncoiled anterior extremity and by near equal dimensions of the vestibule and the uterus. The third species, Ohbayashinema patriciae n. sp., is parasitic in Gansu pika, Ochotona cansus , from China. It is similar to Ohbayashinema erbaevae parasitic in Ochotona dauurica from Buriatia and Ohbayashinema ochotoni in Ochotona macrotis from Nepal, based on the length of the spicules and the ratio of spicule length to body length. It differs from the former species by possessing a smaller number of cuticular ridges and in the comparative length of the vestibule and infundibulum. Related to Oh. ochotoni by an identical number of cuticular ridges at the mid-body, it differs from this species in having smaller ridges in the dorsal rather than ventral field and in the dimensions of the dorsal ray where rays 9 are less than rays 10. Species of Ohbayashinema appear to be host-specific among the Ochotonidae but had not been previously reported in pikas from the Nearctic. Although much remains to be demonstrated about the diversity for helminths in pikas, it is apparent that factors associated with the assembly and structure of parasite faunas have been complex, involving episodic processes for geographic and host colonization along with coevolutionary mechanisms. Understanding the historical factors, particularly climate-driven fluctuations in geographic range, that have structured these faunas suggests that the current regime for global warming and habitat modification has considerable implications for the continuity of already localized assemblages of hosts and parasites.

Description of a new species of Heligmosomoides (Nematoda: Heligmosomidae) parasitic in Microtus limnophius (Rodentia: Cricetidae) from Rangtang, Sichuan, China.

Heligmosomoides craigi n. sp. (Nematoda: Heligmosomoidea) is described from Microtus limnophilus Büchner, 1889 (Rodentia: Cricetidae) from Rangtang, Sichuan, China. It is related to H. protobullosus Asakawa, 1987 and H. longispiculum Tokobaev & Erkulov, 1966 both parasites of Microtus spp. from Japan and USSR, respectively by the following features: a ratio of spicule length/body length of more than 45% and rays 9 shorter than rays 10. The new species is differentiated by rays 8 being closed to rays 6 and 19-22 cuticular ridges versus 14 in H. protobullosus (synlophe not described in H. longispiculum). H. longicirratus (Schulz, 1954) also a parasite of Microtus sp. from the USSR is the most closely related species based on the number of cuticular ridges (20) and the ratio of spicule length/body length (48% versus 50%). There are no illustrations of this species and the female has not been described; for that reason, it is not possible to compare it accurately with our specimens.

Geography and host biogeography matter for understanding the phylogeography of a parasite.

The co-evolution between hosts and parasites has long been recognized as a fundamental driver of macro-evolutionary patterns of diversification. The effect of co-differentiation on parasite diversification is, however, often confounded by underlying geographic patterns of host distribution. In order to disentangle the confounding effects of allopatric versus host speciation, the mitochondrial cytochrome b (cyt b) gene was sequenced in seventy individuals of the parasitic nematode genus Heligmosomoides sampled in the six Apodemus mice species common in the western Palearctic region. The nuclear internal transcribed spacers (ITS) 1 and 2 were also sequenced in fifteen parasites to confirm the mitochondrial data. All lineages differentiated according to a geographic pattern and independently from the sampled host species. This suggests that host speciation did not involve concurrent parasite speciation. However, the geographic distribution range of some parasite lineages mirrors that of A. sylvaticus lineages in SW Europe, and that of A. flavicollis lineages in the Balkans and in the Middle East. Thus, regional co-differentiation likely occurred between the parasite and the two sister Apodemus hosts in different parts of their distribution range. We suggest that differences in regional abundances of A. sylvaticus and A. flavicollis are responsible for generating this pattern of regional co-differentiation. This study highlights the importance of integrating both geography and biogeographic information from potential hosts to better understand their parasite phylogeography.

Description of two new species of Nippostrongylinae (Nematoda: Heligmonellidae) coparasites in three sympatric species of Mastomys spp. (Rodentia: Muridae) from Senegal.

Two new species of heligmosomoid Trichostrongylina nematodes belonging to the genera Neoheligmonella Durette-Desset, 1970 and Heligmonina Baylis, 1928 are described. They are parasitic in the small intestine of three species of Mastomys from Senegal living in sympatry: M. natalensis (Smith, 1834), M. erythroleucus (Temminck, 1853) and M. huberti (Wroughton, 1909). Neoheligmonella granjoni n. sp. is closely related to three species from Senegal. They concern: N. bai Diouf & Durette-Desset, 2002 and N. dielmensis Diouf, Bâ & Durette-Desset, 1998, both parasitic in Arvicanthis niloticus Geoffroy, 1903 and N. mastomysi Diouf et al., 1998, a parasite of M. erythroleucus. N. granjoni n. sp. differs from these species by having 15 cuticular ridges at mid-body versus 13, a large carene and spicules taking up 10-15% of body length versus 5.3-7.1%. Heligmonina kanei n. sp. differs from the most related species H. kotoensis Diouf, Daouda & Durette-Desset 2005, a parasite of M. natalensis from Benin in the following features: spicules taking up 11.6% of body length on average versus 16.8%; a female tail three times longer than the distance anus-vulva versus a tail of equivalent size to this distance. In N. granjoni n. sp., where the material is abundant in all three hosts, the infra-specific variations observed (morphological or morphometrical) were not related to the host species. This is the first report of the genera Neoheligmonella and Heligmonina in M. huberti. The relevance of the phenomenon of host capture concerning the evolution of these two genera is confirmed.

Do lagomorphs play a relay role in the evolution of the Trichostrongyuna nematodes?

In order to confirm or refute the relay role of lagomorphs in the evolution of the Trichostrongylina (Nematoda), the following points were studied by summarizing previous works on the subject: the chronology of the life cycles (27 conducted in natural hosts, lagomorphs, ruminants or arvicolin rodents; 14 in experimental hosts); the parasitic phase in the experimental host and the adaptation involved; the migration of the parasites into the tissues of the host; the morphogenesis of larval stages and molecular phylogeny. These data confirm, in their entirety, that lagomorphs may be considered as "relay" hosts in the evolution of the Trichostrongylina.

Trichostrongylina (Nematoda) from Malagasy Muridae. III--description of a new species of Heligmonoides Baylis, 1928 (Heligmonellidae) parasitic in Mus musculus.

Heligmonoides variabilis n. sp. (Heligmosomoidea, Nippostrongylinae) a parasite of Mus musculus from Madagascar is related to H. afghanus (Tenora, 1969), H. ikeharai Hasegawa, 1990 and H. josephi (Wertheim & Durette-Desset, 1976), all having the dorsal ray divided anterior to the arising of rays 8. H. ikeharai a parasite of Tokudaia muenninki (Muridae) from Japan is the most closely related species with rays 8 arising at mid-length along the dorsal ray. It is differentiated from the new species by very long spicules (almost half of body length) and by the length of the vestibule (almost one millimeter). A new definition of the genus Heligmonoides Baylis, 1928 is proposed with a dichotomic key of the species. The biogeographic distribution and the host spectrum of the genus are described.

Trichostrongylina (Nematoda) parasitic in Phyllotis sp. (Rodentia: Sigmodontinae) from Argentina, with description of three new species.

The Trichostrongylina parasitic in the leaf-eared mouse Phyllotis sp. (Sigmodontinae) from the Province of Catamarca, Argentina are studied. Three new species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Heligmosomoidea: Heligmonellidae: Nippostrongylinae) are described. Stilestrongylus andalgala n. sp. is distinguished from the most closely related species S. moreli Diaw, 1976 parasitic in Auliscomys boliviensis from Bolivia, by the absence of a common trunk of right rays 2 and 3, by left ray 4 shorter than ray 5, and by the shape of the female tail, without a mucron. Stilestrongylus catamarca n. sp. is distinguished from all the other species in the genus by hypertrophied rays 2, larger than rays 3, and from the closely related species Stilestrongylus barusi Durette-Desset, 1971, parasitic in Sigmodontomys alfari from Colombia, by right ray 4 longer than ray 5 and left ray 4 shorter than ray 5, by a larger spicule length/body length ratio (22.6% vs. 7.2%), and by the presence of a mucron on the female tail. Stilestrongylus gracielae n. sp. most closely resembles Stilestrongylus azarai Durette-Desset and Sutton, 1985, parasitic in Akodon azarae and in Graomys griseoflavus, and Stilestrongylus franciscanus Digiani and Durette-Desset, 2003, also parasitic in G. griseoflavus, both from Argentina. These latter differ from the new species by the right lobe of the caudal bursa: in S. azarai rays 4, 5 and 6 arise at same level from their common trunk and in S. franciscanus right rays 4 and 5 diverge at their distal extremity. Lamanema chavezi Becklund, 1963 (Molineoidea: Molineinae), a parasite of South American camelids, is reported in rodents for the second time.

A new species of Hypocristata (Nematoda, Trichostrongyuna, Heligmosomoidea) a parasite of Sigmodon hispidus (Cricetidae, Sigmodontinae) from Venezuela.

Description of Hypocristata tercera n. sp. (Heligmonellidae, Nippostrongylinae) a parasite of the small intestine of Sigmodon hispidus (Rodent, Sigmodontinae) from Venezuela. Two other species were described in the genus, both from Colombia and parasitic in Sigmodontinae. H. thomosomysi Durette-Desset, 1970, a parasite of Thomasomys sp. has about the same number of cuticular ridges at mid-body but differs by ridges having chitinoid struts, a caudal bursa pattern of type 2-2-1 (vs 1-3-1). H. anguillula Durette-Desset, 1970, a parasite of Sigmodontomys alfari (= Nectomys alfari) has the same caudal bursa pattern (type 1-3-1) but differs by the presence of ridges at mid-body in both sexes (absent at that level in H. tercera) and by ridges having chitinoid struts in female. This is the first report of the genus Hypocristata Durette-Desset, 1971 in Venezuela and in the genus Sigmodon (Sigmodontinae).

Three new species of the genus Oswaldocruzia Travassos, 1917 (Nematoda, Trichostrongylina, Molineoidea) parasites of Enyalius spp. (Iguanidae) from Brazil.

Three new species of the genus Oswaldocruzia Travassos, 1917 belonging to the sub-family Molineinae are described from the stomach and/or the small intestine of Enyalius spp. from Brazil. They belong to group 6 of Ben Slimane, Chabaud & Durette-Desset (1996). In this group they share along with O. peruensis Ben Slimane, Verhaag & Durette-Desset, 1995, a parasite of Iguanidae from Peru the followings linked characters: (i) a caudal bursa of type II; (ii) cervical alae present; (iii) undulated cuticular ridges. The Peruvian species differs from the Brasilian species by the absence of a strut in the cervical alae, by a small number of cuticular ridges at mid-body and by a spicular fork with a ramified inner twig. Oswaldocruzio fredi n. sp., a parasite of the stomach and the small intestine of Enyalius iheringii, mainly differs from the two other species by the absence of the oesophageal ventral cuticular ridges. Oswaldocruzia benslimanei n. sp., a parasite of the small intestine of Enyalius bilineatus, differs from Oswoldocruzia burseyi n. sp., a parasite of the stomach of Enyalius perditus, by the division of the fork at 23.4 % of spicule length (versus 32 %), and the length of the blade longer than the fork. Oswoldocruzia subauricularis sensu Freitas, 1955 nec Rudolphi, 1819 and O. mazzai sensu Vicente, 1981 nec Travassos, 1935 should be considered as species inquirendae.

The axis of orientation of the synlophe in the Heligmosomoidea (Nematoda, Trichostrongylina): a new approach.

The definition of the axis of orientation of the synlophe is modified for the Heligmosomoidea so that one or two axes may be recognized. When two axes are present, their inclinations to the sagittal axis are different on the right and left sides, and we propose to name them right axis and left axis, respectively. During the course of evolution, starting from a single oblique axis (plesiomorphic state), an independent rotation of this axis on the right and left sides may bring about a double-axis state with a different inclination on both sides (derived state). When the rotation reaches 90 degrees for both sides, the axis becomes simple once again and is superimposed to the frontal axis (most derived state).

The systematic position of some Ethiopian Nippostrongylinae (Nematoda, Trichostrongylina, Heligmosomoidea) from the National Collection of Animal Helminths, Onderstepoort, South Africa.

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection of Animal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurements and the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Bâ & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in the number of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorter than the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.

Additional molecular evidence to support a sister taxon relationship between Heligmosomoidea and Molineoidea nematodes (Trichostrongylina).

Sequences of the first and second internal transcribed spacers of the ribosomal DNA were used to infer the evolutionary relationships of 19 species of parasitic nematode belonging to three superfamilies, Trichostrongyloidea, Molineoidea and Heligmosomoidea, within the sub-order Trichostrongylina. Analyses using maximum parsimony, maximum likelihood and neighbor-joining methods revealed strong statistical support for monophyly of each superfamily as defined on morphological criteria. Furthermore, in most analyses, there was also strong support for a sister taxon relationship between the Molineoidea and Heligmosomoidea, which supports the findings of a previous study based on partial LSU rDNA sequence data.

Development of Nematodirus spathiger (Nematoda, Molineoidea) in the rabbit and comparison with other Nematodirus spp parasites of ruminants.

The morphogenesis and chronology of the life cycle of Nematodirus spathiger (Railliet, 1896), a parasite of ruminants, were studied in detail in an experimental host. Twenty-four worm-free rabbits were each infected per os with N. spathiger larvae and were killed at 12 h after infection (12 HAI) and every day from 1 DAI to 23 DAI. By 12 HAI, all the larvae were exsheathed and present in the small intestine. The third moult occurred between 4 DAI and 5 DAI. The last moult occurred between 13 DAI and 16 DAI. The prepatent period lasted 21-24 days. The distribution of N. spathiger along the small intestine of the rabbit was assessed. The chronology of the life cycles was compared for various Nematodirus spp from ruminants in their natural hosts and in the rabbit (N. battus, N. spathiger).

Sutarostrongylus Johnsoni sp. n. (Nematoda: Trichostrongylina, Heligmosomoidea) from the pademelon, Thylogale stigmatica (Marsupialia) from Queensland, Australia.

A new species of heligmosomoid nematode Sutarostrongylus johnsoni sp. n., belonging to the sub-family Herpetostrongylinae Skrjabin & Schultz, is described from the small intestine (duodenum) of the red-legged pademelon, Thylogale stigmatica (Gould, 1860) (Marsupialia: Macropodidae), from north-eastern Queensland, Australia. The only other species of the genus S. kirkpatricki Beveridge & Durelte-Desset, 1986 occurs in the related host, the red-necked pademelon, T. thetis (Lesson, 1827) in south-eastern Queensland. The new species differs in having longer spicules and asymmetrical spicule tips as well as the presence of a comârete which develops on the right ventral aspect of the mid-region of the body. The synlophe of the new species is unusual in that the inclination of the axis of orientation changes from being oblique in the anterior part of the body to being frontal in the posterior part. The same change may occur in some species of Austrostrongylus Chandler, 1924. Current data suggest that species of Sutarostrongylus are limited to a single genus of host, Thylogale Gray, 1837 and support the suggestion that both nematode species exhibit morphological features which are intermediate between those occurring in Herpetotostrongylinae in dasyurid marsupials and those occurring in macropodid marsupials.

Parasites of South African wildlife. XVII. Ostertagia triquetra n. sp. (Nematoda: Trichostrongylina) from the grey rhebuck, Pelea capreolus (Forster, 1790).

Re-examination of Teladorsagia hamata (Mönnig, 1932) Durette-Desset, 1989 reported from grey rhebuck, Pelea capreolus (Forster, 1790) proved it to be a new species of Ostertagi Ransom, 1907. The new species, for which the name Ostertagia triquetra n. sp. is proposed, differs from Teladorsagia hamata in the configuration of the bursal rays (2-1-2 in the former, 2-2-1 in the latter), and in that the interno-dorsal branch of the spicules bears a process that is triangular and convex in the new species, but concave and shaped like an ice-cream scoop in Teladorsagia hamata. Ostertagia triquetra has so far been found only in grey rhebuck in the Eastern Cape Province while Teladorsagia hamata was recorded from springbok, Antidorcas marsupialis (Zimmerman, 1780) and gemsbok, Oryx gazella (Unnaeus, 1758) in the western part of the country.

Development of Trichostrongylus colubriformis and Trichostrongylus vitrinus, parasites of ruminants in the rabbit and comparison with Trichostrongylus retortaeformis.

The parasitic phase of development of both Trichostrongylus colubriformis and Trichostrongylus vitrinus, parasites of ruminants, was studied in detail in the rabbit. In T. colubriformis, the third moult appeared by 4 days after infection (DAI) and the last moult occurred between 10 and 11 DAI. In T. vitrinus, the third moult occurred between 8 and 11 DAI and the last one between 12 and 15 DAI. The prepatent period lasted 16-17 days for T. colubriformis and 20 days for T. vitrinus. The chronology of the life cycles and the distribution of the parasites along the small intestine for various Trichostrongylus spp. from lagomorphs and ruminants in the natural host or in the experimental host were compared. All of these biological parameters indicated a lower level of adaptation of T. vitrinus compared to the other species of Trichostrongylus. The results are fully compatible with the evolutionary scheme based on morphological analyses.

Two new species of Nippostrongylinae (Nematoda: Trichostrongylina: Heligmonellidae) from the grey leaf-eared mouse Graomys griseoflavus (Sigmodontinae) in Argentina.

Two new species of Nippostrongylinae, Hassalstrongylus puntanus n. sp., and Stilestrongylus franciscanus n. sp. are described from the intestine of the grey leaf-eared mouse Graomys griseoflavus (Waterhouse, 1837) (Sigmodontinae) from the Province of San Luis, Argentina. Hassalstrongylus puntanus n. sp. is distinguished from the most closely related species H. dollfusi (Díaz-Ungría, 1963), a parasite of Mus musculus from Venezuela by longer rays 2, shorter rays 4, proximal half of the dorsal ray non-enlarged and a non-retractile female tail. Stilestrongylus franciscanus n. sp. is distinguished from the most closely related species S. flavescens Sutton & Durette-Desset, 1991, a parasite of Oryzomys flavescens from Argentina, by rays 2 and 3 diverging separately from common trunk of rays 2 to 6, and by right ray 3 arising from this trunk more distally than ray 6. Stilestrongylus azarai Durette-Desset & Sutton, 1985, a parasite of Akodon azarae from Buenos Aires, Argentina, was also found parasitizing G. griseoflavus, representing new host and locality records. Some additional morphological data for this species are also provided.