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March 17, 2008
Abstract
The supraordinal mammalian clade Afrotheria was first recognized in its entirety based on DNA analysis dating to the mid-1990s. Since then, this “African clade”, which includes proboscideans, sirenians, hyracoids, tubulidentates, elephant-shrews, tenrecs and chrysochlorids, has been supported by numerous molecular and genomic studies. According to these molecular inferences, the origin of crown Afrotheria goes back into the Cretaceous, with estimates from over 100 to under 80 Mya. Morphological phylogenies have not completely recovered Afrotheria, although its paenungulate core (proboscideans, sirenians and hyracoids) was named in 1945 by the paleontologist George Simpson. Recent paleontological studies concur with molecular ones in evoking some affinities between paenungulates, aardvarks and elephant-shrews. Moreover, the position of tenrecs and golden moles within afrotherians is supported by some recent concatenations of morphological and molecular phylogenetic datasets. The phylogenetic position of Afrotheria relative to the other supraordinal placental clades has been debated, the most recent analyses of genomic and concatenated data support a basal position within Placentalia. Molecular data suggest an African origin for Afrotheria and a long period of endemism on that continent. When adding the paleontological data to this scenario, the paleobiogeographic history of Afrotheria becomes more complex. For instance, these data argue for the broad distribution of afrotherians during the Tertiary and do not exclude their Laurasian origin. In fact, some Laurasian taxa could be closely related to the earliest afrotherians (hyracoids, proboscideans and elephant-shrews) found in the early Eocene of North Africa. Other Afrotherian groups are known with certitude from East Africa since the beginning of the Miocene.
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March 17, 2008
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Examining edge effects is imperative to developing effective conservation and management strategies in fragmented landscapes as they are a key component of how landscape change influences habitat quality. Although medium- to large-bodied mammals are recognised as key components of tropical forests, their responses to forest edges remain poorly documented. Here, we describe how five species of medium- to large-bodied terrestrial neotropical mammals respond to forest-pasture edges along 17 forest patches (ranging in size from 5–4714 ha) and two continuous areas of Amazonian forest in Alta Floresta, Brazil. Tracks from two rodent ( Dasyprocta agouti and Agouti paca ) and three ungulate species ( Tayassu tajacu , Mazama gouazoubira and Tapirus terrestris ) were recorded over 4900 sand track station nights during a 4-month study period. When species occurrences were compared between patch size classes we found a significant interaction between patch size and distance from the nearest forest edge only for ungulates. We discuss the cost-effectiveness of monitoring protocols for large terrestrial mammals in tropical forests based on sand track stations, and how edge effects and patch size can modulate species abundance and distribution.
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March 17, 2008
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G- and nucleolar organizer regions-banded chromosomal sets of some Palearctic Marmota species were examined. Based on G-banding chromosomes homology in different species karyotypes was investigated. A schema of Palearctic marmots' karyotype evolution is proposed. All of the studied marmots karyotypes likely originated from one ancestral karyotype with 2n=38, NF=70 that was similar to the M. caudata and M. menzbieri ones. A 38-chromosomal karyotype within the Palearctic marmots group clearly demonstrates considerable stability. “Good” morphological species, M. caudata , M. menzbieri , M. himalayana , have similar karyotypes, and other species with 2n=38 carry single minor rearrangements of chromosomes. Only two species karyotypes, M. camtschatica and M. kastschenkoi , originated from the prominent chromosomal reorganizations. It may be explained by juvenility of the group or by high stability of ancestral 38-chromosomal karyotype. The one submetacentric pair of chromosomes participates in both of the most important rearrangements in Marmota history that may indicate some instability of this part of marmot karyotype. A combination of karyological and morphological data supports the distinction of all recognized Palearctic species of marmots adding to the list a new one, M. kastschenkoi . A segregation of bobak and camtschatica species group is supported.
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March 17, 2008
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Mammal hairs differ among species and may therefore be used for diagnoses at the species level. We characterized dorsal guard hairs of most small rodent species that may be found in central Buenos Aires province (Argentina), according to their geographic distribution: Cavia aperea , Rattus rattus , R. norvegicus , Mus musculus , Holochilus brasiliensis , Scapteromys aquaticus , Oxymycterus rufus , Oligoryzomys flavescens , Akodon azarae , Deltamys kempi , Calomys laucha and C. musculinus . We provide discriminant functions and a dichotomic key to identify hairs at the species level based on hair length and width and scale morphology observed in specific sections of dorsal guard hairs. Discriminant functions require fewer measurements and are faster than the use of the key.
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March 17, 2008
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Grouping characteristics and population structure of chital ( Axis axis Erxleben), sambar ( Cervus unicolor Kerr), nilgai ( Boselaphus tragocamelus Pallas) and chinkara ( Gazella bennetti Sykes) were studied in dry tropical forests of Ranthambhore Tiger Reserve in semi-arid western India during November 2000 to April 2001. Mean and typical group sizes were highest for chital (winter: 4.7 and 9.2, respectively; summer: 4.5, 7.9), followed by sambar (winter: 3.4, 4.2; summer: 4.2, 6.8), nilgai (winter: 2.9, 4.5; summer: 2.5, 4.9) and chinkara (winter: 2.6, 3.3; summer: 2.5, 3.2). Population structure was biased towards females in chital (86.4 males: 100 females) and sambar (83.2:100), while it was biased towards males in nilgai (116.8:100) and chinkara (119.8:100). Ratio of young to adult females was highest for sambar (38.2 young: 100 females), followed by chinkara (35.2:100), chital (28.0:100) and nilgai (23.9:100). Variations in grouping patterns according to habitat and season have been investigated. The importance of constant monitoring of ungulate population structure is emphasised for this drought prone region.
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March 17, 2008
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We determined the characteristics of hibernation locations of the northern bat Eptesicus nilssonii , Brandt's bat Myotis brandtii /whiskered bat Myotis mystacinus , Daubenton's bat Myotis daubentonii and brown long-eared bat Plecotus auritus in southern Finland during the winters 2002–2003 to 2005–2006. All of the species had species-specific hibernation conditions. E. nilssonii hibernated in colder (2.0±0.1°C) and drier (78.0±0.6%) locations than the other species. A total of 20% of E. nilssonii hibernated in temperatures that were below 0°C. M. daubentonii selected warmer (4.4±0.1°C) and more humid (88.2±0.5%) locations than the other species. M. brandtii/mystacinus usually hibernated clustered up to 13 individuals, while the other three species preferred to hibernate solitary. Most of M. brandtii/mystacinus , E. nilssonii and P. auritus hibernated in crevices, while most of M. daubentonii preferred to hibernate on the wall/ceiling. The number of bats found in each hibernaculum was relatively small. The largest number of bats counted was 121, of which 109 were M. daubentonii . M. brandtii/mystacinus tended to gather in larger numbers (up to 83) than E. nilssonii and P. auritus , which were represented by few individuals (up to 16 and 7, respectively) at each hibernaculum. Knowledge of the bat hibernation requirements is needed, e.g., when manipulating conditions to be more suitable for bat hibernation in subterranean sites.
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