Phylogenetic relationships among species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Trichostrongyloidea: Heligmonellidae: Nippostrongylinae), parasites of myomorph rodents (Rodentia: Muridae) in the Neotropics

The phylogenetic relationships of 14 species of Stilestrongylus were analyzed using the comparative morphology of 21 characters. We obtained 2 shortest trees of 50 steps, with a consistency index of 0.540 and 25 apomorphic character states. Ingroup monophyly was supported on these trees by 2 and 3 synapomorphies, respectively, and the ingroup was defined by the following characters: greater number of ventral ridges relative to the number of ridges dorsally, asymmetric bursa, and externodorsal rays differing in size. Sister-group relationships among Stilestrongylus and the other genera designated as outgroups are relatively consistent with those postulated by Durette-Desset's in a classification of the Nippostrongylinae. The ancestor of the species groups comprising Hassalstrongylus, Guerrerostrongylus, and Stilestrongylus originated and diversified in murids in the Neotropical region. Species of Hassalstrongylus occur in rodents between southeastern North America and the eastern part of South America (Brazil and Argentina), whereas species of Guerrerostrongylus and Stilestrongylus diversified exclusively in rodents in the Neotropics.     

2 new species of Stilestrongylus (Nematoda: Heligmonellidae) parasites of Peromyscus (Rodentia: Cricetidae) from Mexico

Stilestrongylus peromysci n. sp. collected from Peromyscus difficilis (Hidalgo state, México), differs from other species in the genus in number of the spines (30) in the synlophe (both sexes) and because the eighth ray arises from the root of the ninth ray; S. hidalguensis n. sp. parasitised Peromyscus sp. and differs from all other congeneric species in the presence of 24 spines in the male synlophe and in the arrangement of the bursal rays (2-2-1 in the right lobe and 2-3 in the left lobe). A key to the species of Stilestrongylus is provided.     

Litomosoides anguyai n. sp. (Nematoda: Onchocercidae) from Oxymycterus misionalis (Rodentia: Muridae) in the rain forest of Misiones,Argentina

A new species of Litomosoides is described from sigmodontine murids occurring in the rain forests of Misiones, Argentina. Litomosoides anguyai n. sp., a parasite of the abdominal cavity of Oxymycterus misionalis, belongs to the sigmodontis group and is closely related to L. legerae and L. oxymycteri. The new species is differentiated by the salient amphids, an asymmetrical annular thickening of the buccal capsule, by the arrangement of the head and tail papillae, and the shape and size of the microfilaria.     

A new species,Litomosoides odilae n. sp (Nematoda: Onchocercidae) from Oligoryzomys nigripes (Rodentia: Muridae) in the rainforest of Misiones,Argentina

A new species of Litomosoides was collected from the abdominal cavity of Oligoryzomys nigripes (Rodentia: Muridae) in a semideciduous secondary rainforest of Misiones, Argentina. Litomosoides odilae n. sp. belongs to the carinii group and is characterized by the amphids displaced dorsally; buccal capsule with an anterior segment transparent and an annular asymmetrical thickening; esophagus divided, with the posterior glandular portion slightly wider than the muscular; male cloacal aperture strongly protruded; and microfilaria sheathed with an attenuated tail. The morphology of the new species, which is similar to that of L petteri, a parasite of marsupials in Brazil, suggests that host-switching events may have occurred in the diversification of this genus.     

The New World filarial genus Molinema Freitas & Lent, 1939 (Nematoda: Onchocercidae), with a description of four new species parasitic in the Echimyidae (Rodentia)

Systematic Parasitology - Four new species of Molinema (Filarioidea: Onchocercidae), parasites of echimyid rodents in South America, are described: M. algardneri n. sp. from Proechimys...     

A new angiostrongylid (Nematoda) species from the pulmonary arteries of Akodon azarae (Rodentia: Cricetidae) in Argentina

Angiostrongylus morerai n. sp. (Nematoda: Angiostrongylidae) is described from the pulmonary arteries of Azara's grass mouse Akodon azarae (Rodentia: Cricetidae) in Argentina. It is distinguished from its congeners principally by the morphology of the dorsal ray, which is as long, or longer, than the externodorsals and has 2 long branches; the spicule lengths are also greater (400-465 microm). This is the first record of a metastrongyloid from sigmodontine rodents in Argentina.     

Chromosome relationships in three representatives of the genusHolochilus (Rodentia,Cricetidae) from Brazil

The G- and C-banded karyotype ofHolochilus brasiliensis collected in central Brazil (2n=55, AN=56, acrocentric X and Y) can be regarded as the most representative of the ancestral form of the genus.H. magnus (2n=52, AN=58, acrocentric X and Y) andH. brasiliensis vulpinus (2n=40, AN=56), both living in southern Brazil, would be in different phases of chromosome number reduction due to centric fusions.H. magnus, in addition, shows an X of variable morphology and a metacentric Y. This fact, coupled with its distinct morphology and restricted distribution, suggests that it may represent a distinct trend in the genus' main evolutionary line.     

Two new species of Litomosoides (Nematoda: Filarioidea) in Sigmodontines (Rodentia: Muridae) from Rio de La Plata marshland, Argentina

Two new species of coelomic filarioid belonging to Litomosoides are described from sigmodontine murids from the Rio de La Plata marshland, Argentina. Litomosoides bonaerensis n. sp., a parasite of Oligoryzomys delticola, belongs to the carinii group and is close to L. silvai, which differs by the head and tail papillae, buccal capsule and cavity, area rugosa, and morphology of the microfilaria. Litomosoides oxymycteri n. sp., from Oxymycterus rufus, belongs to the sigmodontis group. Differential diagnosis is based on the morphology of the buccal capsule, the head and tail papillae, and microfilaria. The ectoparasitic gamasid Ornithonyssus bacoti, in which several Litomosoides species develop, has been recovered from sigmodontines trapped in the study.     

New Pudicinae (Nematoda,Heligmonellidae) parasite of Trichomys fosteri (Rodentia: Echimyidae) from Pantanal,Brazil

Pudica trichomysae n. sp. (Trichostrongylina, Heligmosomoidea, Helligmonellidae, Pudicinae) from the small intestine of Trichomys fosteri (Rodentia: Echimydae) from the Pantanal of Mato Grosso do Sul is described by light and scanning electron microscopy. Pudica trichomysae n. sp. is characterized by caudal bursa type 2–2-1, proportion of spicules length in relation to body length (SpL/BL) of 17 to 18% left and right, respectively. Dorsal ray divided at about the distal third into two branches, each branch divided into two long sub-branches, rays 9 and 10. Furthermore, this study shows for the first time details of the anterior region demonstrating papillae organization, amphids, derides, and opening of the excretory pore. The posterior end of the caudal bursa showed detail of the genital cone, papillae, and ray 1, and in the female, it showed interrupted ridges between the vulva and anus. In conclusion, the present species is the seventeenth described in the genus in South America and the first in Pantanal.     

A new species of Syphacia (Nematoda: Oxyuridae) from Calomys laucha (Rodentia: Cricetidae) in an agroecosystem of central Argentina

A new oxyurid nematode Syphacia hodarae n. sp. is described from the cecum and rectum of the cricetid rodent Calomys laucha Fischer, 1814 (Sigmodontinae, Phyllotini), captured in an agroecosystem of central Argentina. The new species is distinguished from other members of the genus mainly by the shape of the cephalic plate, presence of cervical alae in females, absence of lateral alae, and absence of deirids. Some characters are shared with Syphacia carlitosi, a parasite of Akodon azarae from the wetlands in Argentina. However, S. hodarae can be differentiated from this species by the absence of ornamentation on the accessory hook of the gubernaculum, length of spicule and gubernaculum, size of the eggs, and distance to the vulva from the anterior end. This is the first record of a Syphacia species from the tribe Phyllotini in Argentina, and the first time a Syphacia species is reported from C. laucha .     

A new flea of the genus Ctenidiosomus (Siphonaptera,Pygiopsyllidae) from Salta Province,Argentina

A new species of flea of the genus Ctenidiosomus Jordan, 1931 (Siphonaptera: Pygiopsyllidae) is described from Phyllotis osilae J. A. Allen, 1901, from Salta Province, Argentina. This is the first time that Ctenidiosomus has been recorded in Argentina. A key to species of males of Ctenidiosomus is presented.     

The relationship of sex and ectoparasite infestation in the water rat Scapteromys aquaticus (Rodentia: Cricetidae) in La Plata, Argentina

I studied the relationship between sex and infestation with ectoparasites in the water rat Scapteromys aquaticus from La Plata river marshland, Argentina. The Relative Density's Index (RDI) for males was 3.90% (females 3.60%). A total of 2653 ectoparasites were collected on 33 male hosts, and 1945 on 31 females. Ectoparasite specific richness (S) and diversity (H) were S = 14, H = 1.17 on males, and S = 10, H = 1.52 on females. The similarity between male and female rodents according to their ectoparasites was 75.00%. Although no ectoparasite species showed significant mean abundance (MA) differences between host sexes (p < 0.05), and only Laelaps manguinhosi prevalence was significantly higher on male hosts (N = 2.01, p < 0.05) in this study, there are reasons to think that the sex of the water rat affects ectoparasite burden and specific richness. This information has epidemiological potential because the closely related Scapteromys tumidus is involved in the transmission of Rickettsia coronii, which causes Marsella fever in humans.     

Six new nematodes of the Heligmonellidae (Trichostrongylina) collected from endemic murines of Sulawesi, Indonesia.

Nematodes in Odilia and Paraheligmonelloides (Trichostrongylina: Heligmonellidae) are first recorded from Sulawesi, Indonesia, with 6 new species from the small intestine of endemic murines: Odilia sulawesiensis n. sp. and Odilia moatensis n. sp. from Rattus xanthurus; Odilia mamasaensis n. sp. and Odilia maxomyos n. sp. from Maxomys musschenbroekii; Paraheligmonelloides eropeplios n. sp. from Eropeplus canus; Paraheligmonelloides paruromyos n. sp. from Paruromys dominator. The 6 species are readily distinguished from congeners in the arrangement and number of the synlophe ridges, dilatation of cuticle, shape of the bursa copulatrix and the spicules, and length ratio of the spicules or the ovejector to body. The intestinal heligmonellid fauna of Sulawesi rats shows affinity to both Sundaland and Australian representatives, reflecting dispersal and speciation history of the nematodes and their hosts.     

Integrative taxonomy, systematics and distribution of the genus Eligmodontia (Rodentia, Cricetidae, Sigmodontinae) in the temperate Monte Desert of Argentina

The systematics and distribution of South American sigmodontine rodents a matter of continuous revision and debate. The silky mice, genus Eligmodontia Cuvier, 1837, are among the most specialized murid rodents endemic to South America and its diversification for desert existence is associated with the uplift of the Andes and the early development of arid landscapes. Aiming to clarify the systematics of the species of silky mice occurring in the driest portion of the temperate Monte Desert in Argentina, qualitative and quantitative external and cranial characters, cytogenetics and molecular relationships, were studied. We characterized three karyotypes of Eligmodontia; two of which are described for the first time, and allocated them to previously named species. E. moreni Thomas, 1896 (2n=52 and FN=50), E. typus Cuvier, 1837 (2n=44 and FN=44) and E. marica Thomas, 1918. The later shows the same diploid number of E. typus, but its X—chromosome is not METACENTRIC but ACROCENTRIC . A discriminant analysis of external and cranial data separates E. moreni from E. typus and E. marica. Whereas these last ones show some degree of overlap. The morphological and chromosomal differentiation of Eligmodontia is sustained by DNA distances. Phylogenetic analyses show two major clades. One formed by E. moreni, E. puerulus and E. hirtipes, sharing a high FN and a northern distribution, and THE other formed by E. typus, E. marica and E. morgani with low FN and a central-southern distribution. Two centers of diversification are proposed to explain the evolution of Eligmodontia.     

Phylogenetic relationships among species of the genus Oligoryzomys (Rodentia,Cricetidae) from Central and South America

González‐Ittig, R. E., Salazar‐Bravo, J., Barquez, R. M. & Gardenal, C. N. (2010). Phylogenetic relationships among species of the genus Oligoryzomys (Rodentia, Cricetidae) from Central and South America. —Zoologica Scripta, 39, 511–526. The genus Oligoryzomys includes several species very similar in external morphology, which has resulted in a confusing specific taxonomy. Accurate species identification is particularly important because several species of Oligoryzomys act as natural hosts of hantaviruses affecting humans. Here, we assign specific status to individuals from a wide geographical area of Argentina and Chile using sequences of the mtDNA control region. We also compare cytochrome b sequences of 14 species recognized from Central and South America to infer the phylogenetic relationships within the genus. In addition, the results were analysed using available data on chromosome numbers, and the host–parasite relationships reported for the genus Hantavirus. We confirm the geographical distribution of Oligoryzomys longicaudatus (Argentina, Chile), Oligoryzomys nigripes (Argentina, Paraguay, Brazil), Oligoryzomys chacoensis (Argentina, Bolivia, Paraguay), Oligoryzomys fornesi (Argentina, Paraguay), Oligoryzomys destructor (Argentina, Bolivia) and Oligoryzomys microtis (Bolivia, Brazil). Oligoryzomys longicaudatus is strongly related to the Oligoryzomys flavescens complex, which comprises four clades; O. nigripes is closely related to Oligoryzomys stramineus, and Oligoryzomys vegetus, to Oligoryzomys fulvescens from Central America. Oligoryzomys chacoensis, O. destructor, O. fornesi, O. longicaudatus, O. microtis, O. nigripes, O. stramineus, Oligoryzomys moojeni, Oligoryzomys rupestris, O. fulvescens and O. vegetus are confirmed as valid species, whereas O. flavescens, Oligoryzomys magellanicus, Oligoryzomys griseolus, Oligoryzomys victus, Oligoryzomys andinus and Oligoryzomys arenalis need exhaustive revision. The sister species to all the remaining entities of the genus was O. microtis, suggesting an Amazonian origin for the genus.     

Paleogenetical study of pre‐Columbian samples from Pampa Grande (Salta,Argentina)

Ancient DNA recovered from 21 individuals excavated from burial sites in the Pampa Grande (PG) region (Salta province) of North‐Western Argentina (NWA) was analyzed using various genetic markers (mitochondrial DNA, autosomal STRs, and Y chromosomal STRs). The results were compared to ancient and modern DNA from various populations in the Andean and North Argentinean regions, with the aim of establishing their relationships with PG. The mitochondrial haplogroup frequencies described (11% A, 47% B, and 42% D) presented values comparable to those found for the ancient Andean populations from Peru and San Pedro de Atacama. On the other hand, mitochondrial and Y chromosomal haplotypes were specific to PG, as they did not match any other of the South American populations studied. The described genetic diversity indicates homogeneity in the genetic structure of the ancient Andean populations, which was probably facilitated by the intense exchange network in the Andean zone, in particular among Tiwanaku, San Pedro de Atacama, and NWA. The discovery of haplotypes unique to PG could be due to a loss of genetic diversity caused by recent events affecting the autochthonous populations (establishment of the Inca Empire in the region, colonization by the Europeans). Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Parasitism of two zoonotic reservoirs Dasyprocta leporina and D. fuliginosa (Rodentia) from Amazonas, with Trichostrongylina nematodes (Heligmonellidae): description of a new genus and a new species

A new genus and a new species of Heligmonellidae nematodes are described parasiting the stomach of three agoutis (two Dasyprocta fuliginosa and one D. leporina) captured in the middle and high Negro river microregion, state of Amazonas, Brazil. The new genus, as well as its type-species, are closely related to the trichostrongylids included in Fuellebornema, particularly on what concerns the pattern of the caudal bursa, but differing from them by the characteristics of the synlophe, that presents a poorly developed carene, when compared to the referred number of body ridges in Freitastrongylus n. gen. and consequently in F. angelae n. sp.,in which the ridges are well developed and the carene at mid-body has a similar size when compared to the ridge situated in front of the right field (ridge no. 5). Caudal bursa is of the type 1-4, with rays 9 shorter than rays 10, with a very long genital cone.