Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 14

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Sigmodontinae
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

The Wilfredomys pictipes [Rodentia: Sigmodontinae] karyotype with comments on the karyosystematics of Brazilian Thomasomyini

100%
Bonvicino C. R., Otazu I.
Acta Theriologica
|
1999
|
tom 44
|
nr 3
Karyotypic analysis of two specimens of Wilfredornys pictipes (Osgood, 1933), collected in the Atlantic forest of Sao Paulo State, Brazil, showed 2n = 36 / FN = 34. Comparative karyologic analysis indicated that W. pictipes was very different from species belonging to the tribe Oryzomyini and to the genus Delomys but similar to Rhipidomys species. These findings indicated that the tribe Thomasomyini is not a karyotypically homogeneous taxon. The low diploid number of W. pictipes is likely to be a derived trait among sigmodontine rodents.
2

Digenean parasites of Sigmodontinae rodents from Argentina: a list of species, new host, and geographical records

75%
Guerreiro Maryins N. B., del Rosario Robles M., Diaz J. I., Panisse G., Navone G. T.
Acta Parasitologica
|
2020
|
tom 65
|
nr 1
3

Factors affecting home range size and overlap in Akodon azarae [Muridae: Sigmodontinae] in natural pasture of Argentina

75%
Priotto J. W., Steinmann A. R.
Acta Theriologica
|
1999
|
tom 44
|
nr 1
Differences in home range size in relation to sex, age, breeding and non-breeding periods were studied Home range size and overlap were examined at different den­sities values in populations of Akodon azarae (Fischer, 1829) on railway banks in southern Cordoba Province (Argentina). The sampling was carried out between October 1994, and February 1997, using the capture-mark-recapture method. Home range size in A, azarae was determined by sex and breeding period, and it was independent of the observed density values. Home range size of males was always larger than that of femaies. Increase of population density during the breeding period affected the degree of intersexual overlap of home range,
4

Genetic studies in representatives of genus Rhipidomys [Rodentia, Sigmodontinae] from Brazil

75%
Andrades-Miranda J., De Oliveira L. F. B., Lima-Rosa C. A. V., Sana D. A., Nunes A. P., Mattevi M. S.
Acta Theriologica
|
2002
|
tom 47
|
nr 2
Karyotypic polymorphism of five taxa of the rodent genus Rhipidomys from the Brazilian Amazon and Cerrado biomes was analysed. Rhipidomys nitela Thomas, 1901 from Amazon has 2n = 48, FN = 68. The other species, all have 2n = 44, but can be separated into two groups, one with high FNs (76, 80) and the other with low FNs (48, 52). Two cytotypes of R. mastacalis (Lund, 1840) with high FNs were trapped in four localities of the Cerrado, showing 19 and 17 biarmed autosomes, respectively. A low FN (48) was observed in R. leucodactylus (Tschudi, 1844) in two localities of the Cerrado and FN = 52 in one locality in the Cerrado and the Amazon. All taxa with 2n = 44 have a medium-sized acrocentric X chromosome and a small Y. Rhipidomys nitela is different from the species with 2n = 44 by presenting a heterochromatic short arm of the X chromosome. In all karyotypes analysed, the nucleolus organizer regions were located in the short arms of two to six pairs and the (T2AG3)n telomeric probes hybridized in situ in both the short and long arms of all pairs of the karyotypes.
5

Fur mites of the family Listrophoridae (Acariformes: Sarcoptoidea) associated with South American sigmodontine rodents (Cricetidae: Sigmodontinae)

63%
Sikora B., Bochkov A. V.
Acta Parasitologica
|
2012
|
tom 57
|
nr 4
Six species of 3 genera belonging to the fur mite family Listrophoridae were recorded on skins of South American rodents of the cricetid subfamily Sigmodontinae housed in the Bavarian State Collection of Zoology (Munich, Germany). Among them, Amlistrophorus geoxus sp. nov. from Geoxus valdivianus from Chile is described as a new for science, and males of Prolistrophorus amazonicus amazonicus Fain, 1971 are recorded for the first time. The full generic status for the subgenus Amlistrophorus of the genus Prolistrophorus proposed by Fain et al. (1996) is not supported, and Prolistrophorus musculinus Fain, 1973 stat. nov. (formerly a subspecies of P. amazonicus) from Mus musculus (Rodentia: Muridae) from Suriname is raised to species status. New hosts are recorded for the following species: Prolistrophorus argentinus (Hirst, 1921) from Holochilus brasiliensis and H. chacarius from Argentina, P. amazonicus from Calomys callosus from Argentina and Bolivia, C. laucha and C. musculinus from Argentina, P. akodon Fain and Lukoschus, 1982 from Akodon montensis from Argentina, P. nectomys Fain, 1971 from Nectomys palmipes from Peru and Melanomys caliginosus from Panama, and Sclerolistrophorus oxymycteris Fain, 1976 from Oryzomys laticeps from Brazil.
6

The phylogenetic relationships of the Andean swamp rat genus Neotomys (Rodentia, Cricetidae, Sigmodontinae) based on mitochondrial and nuclear markers

63%
Martinez J. J., Ferro L. I., Mollerach M. I., Barquez R. M.
Acta Theriologica
|
2012
|
tom 57
|
nr 3
The aim of this study was to assess the phylogenetic position of the South American cricetid genus Neotomys using two molecular markers: one nuclear (Irbp) and one mitochondrial (mt-cyb). This genus is currently considered as incertae sedis in the Sigmodontinae radiation. The phylogenetic relationships were estimated using three approaches: Bayesian inference, maximum likelihood and parsimony. We found the genus Neotomys closely related to the genera Euneomys and Irenomys, which are also considered incertae sedis. Our results suggest a common origin for this group of genera; this fact should be reflected in the taxonomy as a supra generic group with a tribal level. However, further and deeper analysis of both molecular and morphological data are needed to diagnose and formalize the proposed tribe. The relationships of this clade to the other members of Sigmodontinae were not clear as assessed by these data sets. The three genera are distributed around the Central and Southern Andes in South America evidencing that the Andes have played an important role in the diversification of several tribes of sigmodontine rodents.
7

Body composition and gut length of Akodon azarae [Muridae: Sigmodontinae]: relationship with energetic requirements

63%
Del V. J. C., Busch C.
Acta Theriologica
|
2003
|
tom 48
|
nr 3
Akodon azarae (J. Fischer, 1829) is a small omnivorous murid rodent that lives in environments with seasonal fluctuations of food. Seasonal variation in its body com­position and gut length, in relation to reproductive status, was studied. Physical Condition Index (PCI) and body composition showed seasonal differences, however, there were no differences in intestine length. The PCI was higher for both mature males and reproductive females compared to immature males and non-reproductive females. Lipid, protein and ash content showed differences in relation to reproductive status. The results suggest that A. azarae meets the additional costs of pregnancy and lactation by increasing energy intake, without relying on reserves.
8

Karyologic diversification and phylogenetic relationships of the genus Thalpomys (Rodentia, Sigmodontinae)

63%
De A. A. F. B., Bonvicino C. R., Briani D. C., Kasahara S.
Acta Theriologica
|
2004
|
tom 49
|
nr 2
We describe the karyotype of Thalpomys species, from different Brazilian localities of the Cerrado. Thalpomys cerradensis Herskovitz, 1990 showed 2n = 36, FN = 34 and T. lasiotis Thomas, .1916 2n = 38, FN = 38. Comparisons of G-band karyotypes showed evident inter-specific homologies indicating that their chromosome complements could be derived from one another by two presumed rearrangements. Both species showed pericentromeric C-band regions in almost all chromosomes but a comparison with CMA3/DA/DAPI staining indicated that the molecular content of heterochromatic regions was different. T. lasiotis specimens from two different localities differed in the morphology of the X chromosome due to the presence of a short heterochromatic arm. These chromosome types are apparently fixed in each population rather than maintained as a polymorphic variation. Phylogenetic analyses supported the monophyly of the genus Thalpomys but was not capable of elucidating its phylogenetic relationship to other Akodontini rodents. These analyses also showed inter-individual variation in T. lasiotis, even within a given population. Phylogenetic analyses placed T. lasiotis specimens with different karyotypes in different monophyletic branches. Molecular and karyologic data confirmed the identity of the genus Thalpomys.
9

Size and overlap of home range in Calomys musculinus [Muridae: Sigmodontinae]

63%
Steinmann A. R., Priotto J. W., Castillo E. A., Polop J. J.
Acta Theriologica
|
2005
|
tom 50
|
nr 2
Home range size and overlap ofCalomys musculinus (Thomas, 1913) was examined in relation to sex and breeding periods. The study was carried out in four 0.25 ha enclosures, in a natural pasture, between October 2002 and July 2003. The four enclosures functioned as independent populations and each was considered a replicate. The capture, mark and recapture method was used. Home range size and overlap inC. musculinus depended on sex and period. Home range size of males was always larger than that of females. Females showed a small degree of intra-sexual home range overlap during the breeding period. In general, male home ranges overlapped with females. We conclude that differences in home range size inC. musculinus is determined by sex and breeding period. Moreover, the degree of inter- and intra-sexual home range overlap during the breeding period suggests that both males and females ofC. musculinus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by the distribution of females. A promiscuous-polygynous mating system is suggested forC. musculinus.
10

Taxonomy and distribution of the sigmodontine rodents of genus Necromys in central Argentina and Uruguay

63%
Galliari C. A., Pardinas U. F. J.
Acta Theriologica
|
2000
|
tom 45
|
nr 2
The taxonomic status of the species of Necromys Ameghino, 1889 (= Bolomys Thomas, part), inhabiting the pampean region of Argentina and southern Uruguay is not clear. The two most recent systematic hypotheses both distinguish two species. Massoia and Fornes (1967) recognized Necromys obscurus (Waterhouse, 1837) with allopatric populations in southern Uruguay and southeastern Buenos Aires Province (Argentina), and N. benefactus (Thomas, 1919) distributed in a strip across northwestern­-southwestern Buenos Aires Province. Reig (1987) argued that the populations of Uruguay and northwestern Buenos Aires Province belong to N. obscurus (including N. benefactus as a subspecies), while those of the southeast and southwest are referred to an unnamed taxon. To solve this problem, 152 specimens from Argentina and Uruguay were studied using morphometric data and qualitative characters. Craniodental variables were measured in 97 adult specimens of both sexes. Discriminant-function analysis among preestablished geographic groups and cluster analysis using Mahalanobis distances revealed the presence of two groups with contrasting morphological charac­teristics. The first group, which corresponds to N. benefactus, includes the populations from northern La Pampa, southern Santa Fé, and northwestern, centralwest, and southwestern Buenos Aires Province (Argentina). The second group, N, obscurus, includes the populations from Uruguay (N. obscurus obscurus) and from southeastern Buenos Aires Province (a new subspecies).
11

New species and records of the mite genus Prolistrophorus (Acariformes: Listrophoridae) from rodents of the subfamily Sigmodontinae (Rodentia: Cricetidae)

51%
Bochkov A. V., Lereschi M., Barreto M.
Acta Parasitologica
|
2014
|
tom 59
|
nr 4
Six fur-mite species of the genus Prolistrophorus Fain, 1970 (Acariformes: Listrophoridae) were recorded from Central and South American rodents of the subfamily Sigmodontinae (Rodentia: Cricetidae). Among them, Prolistrophorus (Aprolistrophorus) parabidentatus sp. nov. from Akodon azarae from Argentina and Prolistrophorus (Aprolistrophorus) tylomys sp. nov. from Tylomys nudicaudus from Guatemala are described as new for science. New hosts are recorded for the following species: Prolistrophorus (Prolistrophorus) grassii (Radford, 1954) from Zygodontomys brevicauda from Colombia, P. (P.) frontalis (Hirst, 1921) from Oligoryzomys sp. from Argentina, P. (P.) argentinus (Hirst, 1921) from Melanomys caliginosus, Akodon affinis from Colombia and Scapteromys aquaticus from Argentina, Prolistrophorus (Beprolistrophorus) hirstianus Fain, 1973 from Scapteromys aquaticus from Argentina.
12

Assessment of Akodon cursor (Rodentia, Sigmodontinae) as permissive host to Schistosoma mansoni infection: morphology of adult worms

51%
Machado-Silva J. R., Heisler Neves R., Rodrigues-Silva R., Figueiredo de Oliveira R. M., Maldonado Junior A.
Acta Parasitologica
|
2011
|
tom 56
|
nr 2
The natural infection with parasitic helminths is common in wild rodent populations. Once such interactions are better understood in the laboratory, it will be more feasible to extend the findings to infected hosts in nature. The flukes recovered from laboratory-infected Akodon cursor at 63 days post-infection were stained with hydrochloric carmine and individually mounted on glass slide as whole-mounts. Light and laser scanning confocal microscopy studies of adult male and female Schistosoma mansoni are reported. The parasites were examined morphologically and biometrically, which was obtained in a digital system for image analysis. Parameters used were: tegument thickness, digestive, excretory and reproductive systems. The overall conclusion of this experiment is that the morphological features of adult worm were similar to laboratory mice. It has been confirmed that the grass mouse is a permissive host to S. mansoni infection.
13

A new species of sigmodontine rodent from the Atlantic forest of Eastern Brazil

51%
De O. J. A., Bonvicino C. R.
Acta Theriologica
|
2002
|
tom 47
|
nr 3
We describe a new sigmodontine species on the basis of three specimens obtained from a high-altitude locality in the Atlantic forest of eastern Brazil. This new form, a small-bodied pentalophodont with tail longer than head and body, long soft fur, and a brownish ochraceous dorsum, is diagnosed by the presence of an open slit in the suture between the frontal bones in prepared skulls, and by a reduced diploid number of 20 coupled with a relatively high fundamental number of 34. Although the low diploid number suggests a derived sigmodontine, analyses of morphological characters and DNA sequence data (720 bp of the cytochrome-6 gene) point to its placement within the recently described genus Juliomys González, 2000, a taxon regarded as belonging to an old and independent sigmodontine lineage. This finding reinforces current hypotheses of the Atlantic forest domain as an important center of diversification for a primitive sigmodontine stock. It also suggests that at least some surviving lineages, often considered rather ancient and unspeciose relicts, were subject to relatively more recent speciation events.
14

Anoplocephalid cestodes of wood rats [Neotoma spp.] in the Western U.S.A.

51%
Haukisalmi V., Rausch R. L.
Acta Parasitologica
|
2006
|
tom 51
|
nr 2
This study reviews the taxonomy of anoplocephaline cestodes of wood rats, Neotoma cinerea, N. fuscipes and N. mexicana (Sigmodontinae) in the western and south-western U.S.A. The anoplocephaline fauna included five species, only one of which, Andrya neotomae Voge, 1946, was relatively common and occurred in all three host species. Other species were Paranoplocephala freemani Haukisalmi, Henttonen et Hardman, 2006, P. primordialis (Douthitt, 1915), both host-generalist species of North American rodents, and two apparently undescribed species of Paranoplocephala s. str. Aprostatandrya octodonensis Babero et Cattan, 1975 from the indigenous South American rodent Octodon degus is regarded as a junior synonym of A. neotomae. A redescription is provided for A. neotomae.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.