Genomic imprinting is responsible for monoallelic gene expression that depends on the sex of the parent from which the alleles (one active, one silent) were inherited. X-chromosome inactivation is also a form of monoallelic gene expression. One of the two X chromosomes is transcriptionally silenced in the somatic cells of females, effectively equalising gene dosage with males who have only one X chromosome that is not complemented by a gene poor Y chromosome. X chromosome inactivation is random in eutherian mammals, but imprinted in marsupials, and in the extraembryonic membranes of some placentals. Imprinting and X inactivation have been studied in great detail in placental mammals (particularly humans and mice), and appear to occur also in marsupial mammals. However, both phenomena appear to have evolved specifically in mammals, since there is no evidence of imprinting or X inactivation in non-mammalian vertebrates, which do not show parent of origin effects and possess different sex chromosomes and dosage compensation mechanisms to mammals.¶ In order to understand how imprinting and X inactivation evolved, I have focused on the mammals most distantly related to human and mouse. I compared the sequence, location and expression of genes from major imprinted domains, and genes that regulate genomic imprinting and X-chromosome inactivation in the three extant mammalian groups and other vertebrates. Specifically, I studied the evolution of an autosomal region that is imprinted in humans and mouse, the evolution of the X-linked region thought to control X inactivation, and the evolution of the genes thought to establish and control differential expression of various imprinted loci. This thesis is presented as a collection of research papers that examines each of these topics, and a review and discussion that synthesizes my findings.¶ The first paper reports a study of the imprinted locus responsible for the human Prader-Willi and Angelman syndromes (PWS and AS). A search for kangaroo and platypus orthologues of PWS-AS genes identified only the putative AS gene UBE3A, and showed it was in a completely different genomic context to that of humans and mice. The only PWS gene found in marsupials (SNRPN) was located in tandem with its ancient paralogue SNRPB, on a different chromosome to UBE3A. Monotremes apparently have no orthologue of SNRPN. The several intronless genes of the PWS-AS domain also have no orthologues in marsupials or monotremes or non-mammal vertebrates, but all have close paralogues scattered about the genome from which they evidently retrotransposed. UBE3A in marsupials and monotremes, and SNRPN in marsupials were found to be expressed from both alleles, so are not imprinted. Thus, the PWA-AS imprinted domain was assembled from many non-imprinted components relatively recently, demonstrating that the evolution of imprinting has been an ongoing process during mammalian radiation.¶ In the second paper, I examine the evolution of the X-inactivation centre, the key regulatory region responsible for X-chromosome inactivation in humans and mice, which is imprinted in mouse extraembryonic membranes. By sequencing and aligning flanking regions across the three mammal groups and non-mammal vertebrates, I discovered that the region homologous to the X-inactivation centre, though intact in birds and frogs, was disrupted independently in marsupial and monotreme mammals. I showed that the key regulatory RNA of this locus (X-inactive specific transcript or XIST) is absent, explaining why a decade-long search for marsupial XIST was unsuccessful. Thus, XIST is eutherian-specific and is therefore not a basic requirement for X-chromosome inactivation in all mammals.¶ The broader significance of the findings reported in these two papers is explored with respect to other current work regarding the evolution and construction of imprinted loci in mammals in the form of a review. This comparison enabled me to conclude that like the PWS-AS domain and the X-inactivation centre, many domains show unexpected construction from disparate genomic elements that correlate with their acquisition of imprinting.¶ The fourth and last paper examines the evolution of CCCTC-binding Factor (CTCF) and its parologue Brother Of Regulator of Imprinted Sites (BORIS) which contribute to the establishment and interpretation of genomic imprinting at the Insulin-Like Growth Factor 2/H19 locus. In this paper I show that the duplication of CTCF giving rise to BORIS occurred much earlier than previously recognised, and demonstrate that a major change in BORIS expression (restriction to the germline) occurred in concert with the evolution of genomic imprinting. The papers that form the bulk of this thesis show that the evolution of epigenetic traits such as genomic imprinting and X-chromosome inactivation is labile and has apparently responded rapidly to different selective pressures during the independent evolution of the three mammal groups. I have introduced these papers, and discussed them generally in terms of current theories of how and why these forms of monoallelic expression have evolved in mammals.

The gliding petaurids are small sized arboreal and nocturnal marsupials restricted to Australia and the New Guinean region. They have suffered range contractions since European settlement, and most of the species are of conservation concern, either nationally or at a state level. This study applied molecular approaches to investigate several questions involving Petaurus species which may provide valuable insights for their conservation and management of species. The objectives of this study included an examination of phylogenetic and evolutionary relationships among Petaurus species, an assessment of phylogeographic structure within P. breviceps and an investigation of genetic diversity, social structure and mating system of P. breviceps in fragmented habitats. A broad molecular systematics study of the genus Petaurus was first undertaken. Two mitochondrial genes (ND2 and ND4) and a nuclear gene marker (ω-globin) were screened for sequence variation in samples obtained from across the distribution of petaurid species, including Australia, New Guinea and its surrounding islands. Phylogenetic analyses confirmed the monophyly of the genus Petaurus and revealed that, with the exception of P. gracilis, the currently recognised species were associated with divergent mtDNA clades. It also revealed considerable mtDNA diversity within the widely distributed species P. breviceps. The existence of at least seven distinct and divergent mtDNA lineages within P. breviceps was supported, with two lineages located in Australia and at least five lineages in New Guinea. However, the distribution of these evolutionary lineages did not correspond with current morphological subspecies boundaries. Analyses of ω-globin sequence provided support for a number of these distinct populations, suggesting the possible presence of cryptic species within P. breviceps. Molecular analyses also suggested that squirrel gliders, P. norfolcensis, may occur in both South Australia and the Northern Territory, extending the current known range of the species. The presence of P. norfolcensis in SA was further verified by examining museum skins. Population structure and current pattern of gene flow within P. breviceps in Australia was examined further to elucidate phylogeographic structure within the species, and explore potential causes of geographic variation. Evidence for significant phylogeographic structuring across the range of the species in Australia was provided from population genetic (AMOVA) and phylogenetic analyses of both mitochondrial DNA and the ω-globin gene. In particular, there was evidence for the existence of two divergent clades that were distributed over distinct geographical regions. Divergence dates calculated for the two major mtDNA clades suggested that environment and climate changes which occurred during the Pliocene may have facilitated this diversification. Habitat fragmentation is generally considered to be a major factor threatening the viability of forest dependent species such as gliders. Effects of habitat fragmentation were therefore investigated in P. breviceps in the highly disturbed landscape of southeastern South Australia. Genetic mating system and social structure of the species in these fragmented habitats was explored in 13 populations, using nine polymorphic microsatellite loci. Social groups consisted of two to seven gliders, and these were often close relatives, including parents with their offspring. Parentage analyses provided some evidence for a polygamous mating system, with a number of males found to have fathered offspring from multiple female partners. Some direct evidence of inbreeding was also found within a small isolated patch. Genetic diversity within P. breviceps populations was moderate compared to the range reported in other marsupial species. Population structure analyses indicated that gene flow between some patches was restricted. Small patches surrounded by a matrix of pine were more likely to show inbreeding and potentially suffer from inbreeding depression, although further data are required to verify this result. Overall, results suggest that, although the species is still present in these small and isolated patches, it may face threats from a lack of dispersal and inbreeding. Maintaining the size of patches and establishing corridors between isolated populations needs to be considered in conservation and management of species in these fragmented habitats. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1295224 / Thesis (Ph.D.) -- School of Earth and Enviromental Sciences, 2007

Thesis (PhD)--Macquarie University, Division of Environmental and Life Sciences, Department of Biological Sciences, 2002. / "November 2001". Bibliography: leaves 136-157.

The name Metatheria refers to the clade that contains the extant marsupials and also all extinct mammals that are more closely related to extant marsupials than to the placental mammals. Metatherians first appear in the fossil record of Asia during the Early Cretaceous, with younger records in North America (Late Cretaceous), South America (the latest Cretaceous or earliest Paleocene), and finally Australia via Antarctica (by the Eocene). The Cenozoic fossil record of metatherians in the Old World is rather poor. Except for Europe, there are only a handful of metatherian taxa known from Afro-Arabia and Asia, almost all of which are documented only by isolated teeth or partial jaws. Fieldwork at Uzunçarşı, a fossil site in central Turkey, yielded at least three different metatherian taxa, one of which (Anatoliadelphys) is exceptionally preserved and nearly complete. In this study I demonstrate that Anatoliadelphys occupies a more derived position on the metatherian tree than the well-known South American metatherians such as Pucadelphys. My functional morphological investigations indicate that Anatoliadelphys and the South American taxa Pucadelphys and Mayulestes are different from the extant didelphid marsupials of South America in their skeletal adaptations for locomotion. Anatoliadelphys was most likely terrestrial. / text

Wombats (Vombatidae, Marsupialia) are fossorial marsupials that are most closely related to koalas amongst living marsupials. The cheek teeth of wombats are unique amongst Australian marsupials in being hypselodont (the condition where the teeth continue to grow throughout life and the formation of roots is suppressed). Hypselodonty is an adaptation to high degrees of tooth wear. The fossil record of vombatids is largely restricted to Pliocene to recent deposits and is largely represented by isolated teeth. Six genera are currently recognised from these deposits, all of which have hypselodont teeth. To date, a single isolated vombatid tooth has been described from pre-Pliocene deposits of South Australia and is the only example of a vombatid cheek tooth that possesses roots. Seventy specimens, representing five species of vombatid, have been recovered from Oligo-Miocene deposits in the Riversleigh World Heritage Site in northwestern Queensland and are described here. Among these are four new species and one new genus. A new species of Warendja from Riversleigh is described. It represents the oldest known hypselodont vombatid. This species is compared with additional specimens of the Pleistocene species of Warendja (W wakefieldi). Three species of Rhizophascolonus and a new monotypic genus are also described. Phylogenetic analysis of these taxa indicates that Rhizophascolonus may represent a sister taxon to the other vombatids. These specimens comprise almost all known examples of Oligo-Miocene vombatids. Most of the specimens are isolated teeth and are highly variable in size and morphology. Cusp detail is clearly preserved on many, allowing for omparison with the cusp morphology on juvenile cheek teeth of the common wombat (Vombatus ursinus). All of the taxa found in the deposits at Riversleigh share a number of characters such as marked differences in enamel thickness and height around the cheek teeth. It is argued here that these shared characters are indicative of high amounts of tooth wear and/or occlusal stresses acting on the trailing edge enamel. Combined with evidence of scratch-digging adaptations of the forelimbs it is suggestive of a rhizophagous niche for at least some of these early vombatids.

Thesis (Ph. D.)--University of New South Wales, 2004. / Title from PDF title page (viewed on Mar. 25, 2006). Includes bibliographical references (p. 264-286).

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-03-14T14:27:57Z No. of bitstreams: 1 KalianeARP_DISSERT.pdf: 1933642 bytes, checksum: d81d7572738a12680036b924e51703d5 (MD5) / Made available in DSpace on 2017-03-14T14:27:57Z (GMT). No. of bitstreams: 1 KalianeARP_DISSERT.pdf: 1933642 bytes, checksum: d81d7572738a12680036b924e51703d5 (MD5) Previous issue date: 2016-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Rickettsia are pathogens with zoonotic potential transmitted by wild and domestic animals, where the occurrence of infections by Rickettsia spp. It happens among populations of wild rodents and marsupials, which has a significant share in the maintenance cycle of these microorganisms in the wild environment. Thus, this study aimed to record the occurrence of Rickettsia sp. in wild rodents and marsupials in the Rio Grande do Norte semi-arid. The work consisted in a field research with wild rodents and marsupials, with data expressed in simple frequency and percentage using IBM SPSS (Armonk, NY: IBM Corp.), version 22.0. Were captured in Sherman and Tomahawk traps, 02 Thrichomys, 03 Wiedomys, 30 Gracilinanus agilis and 06 Monodelphis domestica, which were collected by venipuncture of julgular vein, 36 blood samples of marsupials and 05 of rodents. These were collected 64 Amblyomma auricularium, 07 Amblyomma parvum and 12 Amblyomma sp. Were obtained by centrifugation 36 samples of sera marsupials and 05 rodents and analyzed using Immunofluorescence Assay (IFA). All copies of A. auricularium, Amblyomma sp. and A. parvum were macerated and submitted to DNA extraction and amplification by Polymerase Chain Reaction (PCR) directed to a fragment of gltA and ompA rickettsial genes. Of serum samples obtained from wild rodents and marsupials blood and tested in IFA showed seropositivity for Rickettsia amblyommii, 6.7% G. agilis, 83.3% M. domestica and 50% Thrichomys. Eight samples of A. auricularium were positive for genes in R. amblyommii fragment analysis gltA (350 bp) and ompA (587 bp) with 100% similarity to Candidatus R. amblyommii Bahia and AaPE strain, corresponding to a low circulation agent from the vectors and high among the population of M. domestica. This research records for the first time the occurrence of R. amblyommii in marsupial species G. agilis and M. domestica belonging to Didelphidae family and Echimyidae family rodents Thrichomys genre, in the semiarid region of Rio Grande do Norte, Brazil / Rickettsia são patógenos com potencial zoonótico transmitidos por animais silvestres e domésticos, onde a ocorrência de infecções por Rickettsia spp. acontece entre populações de roedores e marsupiais silvestres, os quais tem relevante participação na manutenção do ciclo desses microrganismos no ambiente silvestre. Desta forma, esse estudo objetivou registrar a ocorrência de Rickettsia sp. em roedores e marsupiais silvestres no semiárido do Rio Grande do Norte. O trabalho consistiu em uma pesquisa de campo, com roedores e marsupiais silvestres, com os dados expressos em frequência simples e porcentagem através do programa estatístico IBM SPSS (Armonk, NY: IBM Corp.), versão 22.0. Foram capturados nas armadilhas Sherman e Tomahawk, 02 Thrichomys, 03 Wiedomys, 30 Gracilinanus agilis e 06 Monodelphis domestica, dos quais foram coletados por venopunção da veia julgular, 36 amostras de sangue de marsupiais e 05 de roedores. Destes foram coletados 64 Amblyomma auricularium, 07 Amblyomma parvum e 12 Amblyomma sp. Foram obtidas por centrifugação 36 amostras de soros de marsupiais e 05 de roedores e analisadas utilizando a Reação de Imunofluorescência Indireta (RIFI). Todos os exemplares de A. auricularium, Amblyomma sp. e A. parvum foram macerados e submetidos a extração de DNA e amplificação através da Reação em Cadeia da Polimerase (PCR) direcionados para um fragmento dos genes gltA e ompA rickettsial. Das amostras de soro obtidas do sangue de roedores e marsupiais silvestres e testadas na RIFI, apresentaram soropositividade para Rickettsia amblyommii, 6,7% de G. agilis, 83,3% M. domestica e 50% Thrichomys. Oito exemplares de A. auricularium estavam positivos para R. amblyommii na análise de fragmentos dos genes gltA (350 pb) e ompA (587 pb), com 100% de similaridade com Candidatus R. amblyommii estirpe Bahia e AaPE, correspondendo a uma baixa circulação do agente dentre os vetores e elevada entre a população de M. domestica. Esta pesquisa registra pela primeira vez a ocorrência de R. amblyommii em marsupiais das espécies G. agilis e M. domestica pertencentes a família Didelphidae e roedores da família Echimyidae do gênero Thrichomys, no semiárido do Rio Grande do Norte, Brasil / 2017-03-13

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-03-27T15:32:23Z No. of bitstreams: 1 VivianeM_DISSERT.pdf: 2379104 bytes, checksum: 52e3047f467ee1b880b505c71e68f077 (MD5) / Made available in DSpace on 2017-03-27T15:32:24Z (GMT). No. of bitstreams: 1 VivianeM_DISSERT.pdf: 2379104 bytes, checksum: 52e3047f467ee1b880b505c71e68f077 (MD5) Previous issue date: 2016-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Caatinga biome occurs in the states of the states of Maranhão, Piauí, Ceará, Rio Grande do Norte, Pernambuco, Paraíba, Alagoas, Sergipe, Bahia and Minas Gerais, in Brazil. Despite being the only exclusively Brazilian ecosystem, few resources for research on biodiversity and conservation are devoted to this biome. The generation of knowledge on biodiversity of the Caatinga is essential for establishing effective strategies for management and conservation of species and habitats, particularly in a biome as sensitive and as threatened this one. The present work is divided into two chapters. The first one is an extensive literature review on the occurrence, distribution and chromosomal characteristics of species of small terrestrial mammals recorded in the Caatinga. The second chapter presents data on diversity, ecology and seasonality of a community of small terrestrial mammals (Didelphimorphia and Rodentia) using capture-marking-recapture methods throughout twelve successive months in a well-preserved native forest fragment of Caatinga located at the Experimental Farm Rafael Fernandes from the Universidade Federal Rural do Semi-Árido, Mossoró-RN / O bioma Caatinga ocorre nos estados do Maranhão, Piauí, Ceará, Rio Grande do Norte, Pernambuco, Paraíba, Alagoas, Sergipe, Bahia e Minas Gerais, no Brasil. Apesar de ser o único ecossistema exclusivamente brasileiro, poucos recursos para pesquisas sobre biodiversidade e conservação são voltados para este bioma. A geração de conhecimento sobre a diversidade biológica da Caatinga torna-se essencial para estabelecer estratégias eficazes de gestão e conservação de espécies e habitats, particularmente em um bioma tão sensível e ameaçado como esse. O presente trabalho se divide em dois capítulos e, o primeiro, consiste em uma extensa revisão bibliográfica sobre a ocorrência, distribuição e características cromossômicas das espécies de pequenos mamíferos terrestres que habitam a Caatinga. O segundo capítulo, apresenta dados sobre diversidade, ecologia e sazonalidade de uma comunidade de pequenos mamíferos terrestres (Didelphimorphia e Rodentia) através de um estudo usando o método de captura-marcação-recaptura ao longo de doze meses sucessivos de amostragem em um fragmento de mata nativa de Caatinga bem conservada situada na Fazenda Experimental Rafael Fernandes da Universidade Federal Rural do Semi-Árido, Mossoró-RN / 2017-03-24

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A ordem Didelphimorphia, de marsupiais americanos, apresenta 19 gêneros e 96 espécies, todos membros da família Didelphidae, que é dividida em duas subfamílias, Caluromyinae e Didelphinae. A subfamília Didelphinae contém (não apenas) as tribos Didelphini e Metachirini. A tribo Didelphini compreende 15 espécies de quatro gêneros: Chironectes (1 espécie), Lutreolina (1), Didelphis (6) e Philander (7) e a tribo Metachirini é monotípica, com apenas uma espécie do gênero Metachirus. Estes cinco gêneros encontram-se distribuídos amplamente pelas Américas, desde o sul do Canadá até a região central da Argentina. O objetivo deste estudo foi buscar identificar e explicar, através de análise pan-biogeográfica, os padrões de distribuição das espécies destes cinco gêneros. Para tal, foi feito um levantamento em banco de dados, coleções científicas e artigos científicos para a obtenção de dados sobre as localidades de registro de cada espécie. Estas foram então marcadas em mapas e a partir destes, as localidades de ocorrência foram conectadas com linhas de menor distância para formação dos traços individuais. Pela sobreposição dos traços individuais chegou-se aos traços generalizados e do encontro destes, aos nós biogeográficos. Os pontos de ocorrência foram também plotados em mapas de biomas para análise. Encontramos três traços generalizados e dois nós biogeográficos, um no centro da Bolívia na província biogeográfica de Puna e outro na Argentina, na província de Misiones. Quatro espécies não participaram de nenhum dos traços generalizados, provavelmente devido à sua distribuição mais restrita (Philander deltae, P. andersoni, P. olrogi e P. mcilhennyi). Chironectes minimus e Metachirus nudicaudatus tiveram seus traços coincidentes com dois traços generalizados, o que está de acordo com suas divisões de subespécies. Identificamos os diferentes padrões existentes para o norte da América do Sul (Venezuela) já apontado por diversos autores, porém apenas quando analisadas as subespécies em separado. Alguns limites para a distribuição das espécies puderam ser identificados, como por exemplo o istmo de Tehuantepec, no México, para Chironectes minimus e Metachirus nudicaudatus e o limite da região neotropical para P. opossum e D. marsupialis. O limite de distribuição sul de Philander opossum e P. frenatus é provavelmente o rio Paraguai, que deve servir de barreira para o contato entre as duas espécies. A descaracterização dos ambientes naturais pelo desmatamento vem alterando os padrões naturais de distribuição das espécies, com o registro de espécies de áreas abertas em biomas de mata. Lutreolina crassicaudata apresenta distribuição disjunta, ocupando duas áreas de vegetação aberta, uma no noroeste e outra no centro e sudeste da América do Sul, padrão provavelmente gerado pelos períodos de retração e expansão de áreas de savana do Mioceno superior ao Holoceno, levando à captura destes enclaves de vegetação aberta, com seu isolamento por áreas de floresta. Os nós e traços generalizados aqui identificados coincidiram com os encontrados por outros autores. Apesar da pan-biogeografia poder ser usada para propor áreas de proteção ambiental, nos locais em que encontramos os nós biogeográficos já existem unidades de conservação, não havendo assim necessidade de propor novas áreas no caso desses marsupiais. Ainda existe uma grande necessidade de um melhor conhecimento da distribuição e taxonomia das espécies estudadas, o que promoveria um melhor entendimento dos padrões biogeográficos existentes / The order Didelphimorphia, family Didelphidae of American marsupials includes 19 genera and 96 species and is divided into two subfamilies, Caluromyinae and Didelphinae. The subfamily Didelphinae contains (not exclusively) the tribes Didelphini and Metachirini. The tribe Didelphini comprises 15 species of four genera: Chironectes (1 species), Lutreolina (1), Didelphis (6) and Philander (7) and Metachirini tribe is monotypic, with only one species of the genus Metachirus. These five genera are widely distributed throughout the Americas, from southern Canada to central Argentina. The aim of this study was to identify and to explain the speciess distribution patterns trough pan-biogeographic analysis. So, a survey was carried on using databases, visiting scientific collections and searching for published records to obtain data on localities were species were registered. Localities, for each separate species were marked on maps and the most close localities were connected with lines (individual tracks). The overlapping of individual tracks are the generalized tracks and the intersection of two or more generalized tracks are called nodes. Localities were also plotted on biomes maps. We found three generalized tracks and two nodes, one in the center of Bolivia in the biogeographic province of Pune and the other in Argentina, in Misiones. Four species do not participated in any generalized tracks, probably due to its restricted distribution (Philander delta, P. andersoni, P. olrogi and P. mcilhennyi). Chironectes minimus and Metachirus nudicaudatus had their tracks overlapped with two generalized tracks, which is in accordance with their known subspecies geographic distribution. In those species which are divided in subspecies, a separate analysis was carried on. Different patterns on the northern South America (Venezuela) were identified, all already pointed out by authors. Some species distribution limits were identified, such as the Tehuantepec Isthmus in Mexico for C. minimus and M. nudicaudatus and the neotropical region north limit to P. opossum and D. marsupialis. The south limit of P. opossum and P. frenatus is the Paraguay river, which seems to be a barrier. The mischaracterization of natural environments by human activities is changing the natural distribution patterns, as we can see by the occurrence of open areas species in forest biomes. Lutreolina crassicaudata presents a disjunct distribution, occupying two open vegetation areas, in northwest and center-southeast South America, probably generated by periods of contraction and expansion of savanna areas during the later Miocene to Holocene, leading to open vegetation enclaves surrounded by forests. The generalized tracks that we identified coincided with those found by other authors. Despite the pan-biogeography methodology can be used to propose protected areas, our nodes are in areas where conservation units already exist. There still is a great need for a better data of the distribution and taxonomy of these species, which would promote a better understanding of their biogeographic patterns

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / As florestas tropicais brasileiras (Amazônia e a Mata Atlântica) possuem alta diversidade de espécies e atualmente estão separadas por um cinturão de vegetação aberta. Parte deste cinturão é ocupada pela Caatinga, onde se encontram os Brejos de Altitude, testemunhos das conexões históricas entre a Mata Atlântica e a Amazônia. O Centro de Endemismos Pernambuco (CEPE) é a unidade biogeográfica que compõe a Mata Atlântica ao norte do rio São Francisco e contém diversos táxons endêmicos. Esta região apresenta uma mastofauna compartilhada com a Amazônia, devido às conexões existentes durante o Cenozóico. A presença do rio São Francisco em seu limite sul pode atuar como barreira ao fluxo gênico e explicar os endemismos encontrados no CEPE. Contrastando com sua situação peculiar, a mastofauna do CEPE ainda carece de estudos aprofundados sobre a identificação de suas espécies, padrões geográficos e relações filogenéticas. Revisões recentes têm identificado espécies diferentes ao norte e ao sul do rio São Francisco, mas poucos trabalhos têm proposto hipóteses biogeográficas para o CEPE. Para ampliar o conhecimento sobre a identidade e distribuição geográfica dos pequenos mamíferos do CEPE e sua estrutura filogeográfica, foram realizados levantamentos de espécies e análises de diversidade genética e morfométrica para algumas espécies. Os levantamentos consistiram de visitas às coleções científicas a fim de identificar as espécies ocorrentes no CEPE e excursões de coleta com 5 a 17 noites consecutivas em 12 localidades ao longo do CEPE, que totalizaram 64691 armadilhas noites e resultaram na coleta de 476 exemplares de 31 espécies. As espécies foram identificadas com base na morfologia externa e craniana e por análises citogenéticas. Para investigar a biogeografia do CEPE, análises de genética de populações, filogeográficas e morfométricas foram realizadas para os marsupiais Caluromys philander, Didelphis aurita, Marmosa murina, Metachirus nudicaudatus e os roedores Akodon cursor, Oecomys catherinae e Rhipidomys mastacalis para avaliar a existência de diferenciação nas populações do CEPE e suas relações com as linhagens Amazônicas e Atlânticas. Estes resultados mostraram que a diversificação dos pequenos mamíferos do CEPE ocorreu tanto no Terciário quanto no Quaternário. Algumas populações, como em Caluromys philander e Oecomys catherinae, mostraram afinidades com linhagens amazônicas, enquanto outras, como em Metachirus nudicaudatus e Rhipidomys mastacalis, apresentaram afinidades com linhagens atlânticas. Os pequenos mamíferos do CEPE apresentaram diferenciação em relação às suas linhagens irmãs, com algumas linhagens podendo tratar-se de espécies ainda não descritas (e.g. Didelphis aff. aurita e Rhipidomys aff. mastacalis). Esta diferenciação provavelmente foi causada pelos eventos cíclicos de flutuações climáticas que provocaram elevações no nível do mar e retração das florestas tropicais, isolando as populações do CEPE. Por fim, para auxiliar na identificação das espécies em novas coletas, de suas distribuições geográficas e de suas características citogenéticas e ecológicas, foi elaborado um guia reunindo todas as informações disponíveis sobre as espécies de pequenos mamíferos do CEPE. / The Brazilian tropical rainforests (Amazon and Atlantic Forest) present high species diversity and are currently separated by a belt of open and dry vegetation. Part of this belt is occupied by the Caatinga, where are found the Brejos de Altitude, evidence of the historical connections between the Atlantic Forest and the Amazon. The Pernambuco Endemism Center (CEPE) is the biogeographic unit of the Atlantic Forest located north of the São Francisco River and contains several endemic taxa. Part of its mammal fauna is shared with the Amazon, due to former connections in the Cenozoic. The presence of the São Francisco river in its southern limit may act as a barrier to gene flow and explain the endemism found in CEPE. In contrast to their peculiar situation, the mammalian fauna from CEPE still lacks detailed studies on its taxonomic composition, geographic patterns and phylogenetic relationships. Recent reviews have identified different species in the north and south of the San Francisco river, but few studies have proposed biogeographical hypotheses for the CEPE. In order to increase knowledge on the identity and geographical distribution of the small mammals in the CEPE and their phylogeographic structure, species surveys were carried out and the genetic and morphometric diversity of some of the species found were assessed. The surveys consisted of visits to scientific collections to identify the species occurring in CEPE and trapping trips, with 5 to 17 consecutive nights, in 12 sites throughout the CEPE, totaling 64,691 trap-nights, resulting in the collection of 476 specimens of 31 species. The specimens were identified based on external and cranial morphology and cytogenetic analysis. To investigate the biogeography of CEPE, genetics, phylogeographic and morphometric analysis were performed with the marsupials Caluromys philander, Didelphis aurita, Marmosa murina, Metachirus nudicaudatus and the rodents Akodon cursor, Oecomys catherinae and Rhipidomys mastacalis to assess the existence of differentiation in CEPE populations and their relationships with the Amazon and Atlantic Forest lineages. These results showed that diversification of small mammals in CEPE occurred in both the Tertiary and Quaternary. Some populations, such as Caluromys philander and Oecomys catherinae showed affinities with amazonian lineages, while others, like Metachirus nudicaudatus and Rhipidomys mastacalis, showed affinities with atlantic lineages. The small mammals from CEPE showed differentiation from their sisters lineages, with some lineages probably being, in fact, undescribed species (eg Didelphis aff. aurita and Rhipidomys aff. mastacalis). This differentiation was probably caused by cyclical events of climate fluctuations that led to sea level rises and retractions of the tropical forests, thus isolating the populations in CEPE. Finally, to help identifying species in future field surveys, their geographic distributions and ecological and cytogenetic features, a guide was prepared by gathering all available information on the species of small mammals from CEPE.