Navegando por Assunto "Sigmodontinae"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Análise citogenética de duas espécies do gênero Hylaeamys (Rodentia: Cricetidae) por citogenética clássica e molecular
(Universidade Federal do Pará, 2013-04-05) PINTO, Jamilly Amaral; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
Rodents are one of the largest and oldest orders of the class Mammalia. In South America, the order Rodentia compromises about 42% of mammal species, and from this more than 50% belong to the family Cricetidae, which includes the subfamily Sigmodontinae. The genus Hylaeamys is inserted in the tribe Oryzomyini and corresponds to one of 10 new genera proposed for species and species groups within Oryzomys. Hylaeamys is the equivalent of "megacephalus group", and consists of the species H. acritus, H. laticeps, H. megacephalus, H. perenensis, H. oniscus, H. tatei and H. yunganus, distributed in Venezuela, Trinidad, Guyana, Paraguay and Brazil, in areas of the Amazon rain forest, Atlantic rainforest and savannah. This study aims to analyze chromosomal markers in two species of the genus Hylaeamys, providing data to assist in its taxonomic and cytogenetic characterization. Nineteen samples of Hylaeamys megacephalus (HME) and four samples of Hylaeamys oniscus (HON) were analyzed. HME has 2n = 54 and HON, 2n = 52. The results obtained by G- and C-banding and Fluorescent In Situ Hybridization with whole chromosome probes from Hylaeamys megacephalus made it possible to determine the chromosomal characteristics of the species studied, as well as allowing a comparative analysis between them, and in comparison with Cerradomys langguthi, observing homeologies and karyotypic differences. The two species of Hylaeamys differ by a centric fission/fusion rearrangement in which HON shows the association of the pairs 14/19 of HME. This association is shared with CLA with an inversion (19/14/19). This work is an achievement for phylogeny and chromosomal studies on the genus Hylaeamys.
Acesso aberto (Open Access)
Caracterização cromossômica e mapeamento genômico comparativo de Oecomys paricola e Oecomys auyantepui com sondas de Hylaeamys megacephalus (Cricetidae – Sigmodontinae)
(Universidade Federal do Pará, 2015-05-19) ROSA, Celina Coelho da; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
The Order Rodentia represents the largest mammal order, with approximately 42% of species currently known. Rodents have 2,227 species, 468 genera and 33 families recent, the latter being raised to 50 if the extinct families are considered. Their huge variation in morphology, diversity of habitats and climates and food are the causes of this be most numerous and evolutionarily successful among mammalian orders. The Oecomys genus belongs to the subfamily Sigmodontinae (Cricetidae, Rodentia) with approximately 16 described species, distributed in tropical and subtropical forest of Central and South America. Previous cytogenetic studies suggest that Oecomys features large karyotype diversity, with the diploid number ranging from 58 to 86. In this study were analyzed by conventional cytogenetic techniques and multidirectional chromosome painting (using whole chromosome probes of Hylaeamys megacephalus) 18 specimens of Oecomys were analyzed, four were collected in the metropolitan area of Belém, Pará; two in the city of Santa Barbara, Pará; five in the region of Carajás, Pará and 7 in Calha Norte region, Pará. Specimes from Belém Environmental Park had 2n = 72 and FN = 76; specimes from Santa Barbara had 2n = 70 and FN = 74; from Carajás presented 2n = 70 and FN = 72. All this sample was identified as O. paricola. Specimens collected from the Calha Norte region had 2n = 62 and NF = 80 and were identified as O. auyantepui. The cytotypes described for O. paricola showed differences in five HME peaks, indicating 3 associations for this species. O. auyantepui showed five associations. Chromosomal differences found for O. paricola from different geographic regions suggest that these cytotypes belong to cryptic species. We suggest that these populations of O. paricola are a complex of species where the chromosomal differentiation already happened but not the morphological and molecular ones.
Acesso aberto (Open Access)
Considerações sobre a anatomia funcional e adptativa de alguns sigmodontinae (Mammalia : Rodentia : Muridae)
(Universidade Federal do Pará, 2002-10-29) MELO, Cláudia Cristina de Sousa de Melo; TOLEDO, Peter Mann de; http://lattes.cnpq.br/3990234183124986
Among the mammals, the little rodents makes up a singular group. These animals have been in full evolutive process due to their capacity of reproducing and adapting to different habitats. Philogeneticly, the group still hasn't a sure characteristic and is very similar morphologically to rodents Sigmodontinae from Serra dos Carajás. Through this study of external features and some banes from post-cranium related to motions habit, we beheld: 1) The choice of the habitat in Serra dos Carajás area among the rodents seems not to be related to a phylogenetic standard; 2) It wasn't possible to set a relationship between ecological features and main morphological shape from post-cranium related to body-shape among Sigmodontinae; 3) the morphology of úmero and femur have a strong Phylogenetic sign which is another feature of subfamily Sigmodontinae; 4) the signs intermembal, crural e branquial weren't effective to identify the many way of motions among the rodents Sigmodontinae.