Добірка наукової літератури з теми "Tremarctine bears"

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Статті в журналах з теми "Tremarctine bears"

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Mitchell, Kieren J., Sarah C. Bray, Pere Bover, Leopoldo Soibelzon, Blaine W. Schubert, Francisco Prevosti, Alfredo Prieto, Fabiana Martin, Jeremy J. Austin, and Alan Cooper. "Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America." Biology Letters 12, no. 4 (April 2016): 20160062. http://dx.doi.org/10.1098/rsbl.2016.0062.

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Анотація:
The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear ( Tremarctos ornatus ), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears ( Tremarctos ), South American short-faced bears ( Arctotherium ) and North American short-faced bears ( Arctodus ) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears ( Arctodus and Arctotherium ), potentially as an adaptation to dominate competition for megafaunal carcasses.
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Saremi, Nedda F., Jonas Oppenheimer, Christopher Vollmers, Brendan O’Connell, Shard A. Milne, Ashley Byrne, Li Yu, Oliver A. Ryder, Richard E. Green, and Beth Shapiro. "An Annotated Draft Genome for the Andean Bear, Tremarctos ornatus." Journal of Heredity 112, no. 4 (April 21, 2021): 377–84. http://dx.doi.org/10.1093/jhered/esab021.

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Abstract The Andean bear is the only extant member of the Tremarctine subfamily and the only extant ursid species to inhabit South America. Here, we present an annotated de novo assembly of a nuclear genome from a captive-born female Andean bear, Mischief, generated using a combination of short and long DNA and RNA reads. Our final assembly has a length of 2.23 Gb, and a scaffold N50 of 21.12 Mb, contig N50 of 23.5 kb, and BUSCO score of 88%. The Andean bear genome will be a useful resource for exploring the complex phylogenetic history of extinct and extant bear species and for future population genetics studies of Andean bears.
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FIGUEIRIDO, BORJA, and LEOPOLDO H. SOIBELZON. "Inferring palaeoecology in extinct tremarctine bears (Carnivora, Ursidae) using geometric morphometrics." Lethaia 43, no. 2 (August 19, 2009): 209–22. http://dx.doi.org/10.1111/j.1502-3931.2009.00184.x.

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Bidon, Tobias, Christiane Frosch, Hans G. Eiken, Verena E. Kutschera, Snorre B. Hagen, Siv G. Aarnes, Steven R. Fain, Axel Janke, and Frank Hailer. "A sensitive and specific multiplex PCR approach for sex identification of ursine and tremarctine bears suitable for non‐invasive samples." Molecular Ecology Resources 13, no. 3 (January 25, 2013): 362–68. http://dx.doi.org/10.1111/1755-0998.12072.

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5

Arnaudo, María Eugenia, Néstor Toledo, Leopoldo Soibelzon, and Paula Bona. "Phylogenetic signal analysis in the basicranium of Ursidae (Carnivora, Mammalia)." PeerJ 7 (March 15, 2019): e6597. http://dx.doi.org/10.7717/peerj.6597.

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Ursidae is a monophyletic group comprised of three subfamilies: Tremarctinae, Ursinae and Ailuropodinae, all of which have a rich geographical distribution. The phylogenetic relationships within the Ursidae group have been underexamined, especially regarding morphological traits such as the basicranium. Importantly, the basicranium is a highly complex region that covers a small portion of the skull, combining both structural and functional aspects that determine its morphology. Phylogenetic hypotheses of the Ursidae (including Tremarctinae) have been made based on morphological characters that considers skull, mandible and teeth features, while specific characters of the auditory region and basicranium have not been taken into account. To do this, we analyse the shape and size macroevolution of the basicranium of Ursidae, testing its morphological disparity in a phylogenetic context, which is quantified by means of the phylogenetic signal. We investigated phylogenetical autocorrelation by shape (depicted by Principal Components Analysis scores from previous published analyses) and basicranium size (depicted by centroid size, CS) using an orthonormal decomposition analysis and Abouheif C mean. The main advantages of these methods are that they rely exclusively on cladogram topology and do not require branch-length estimates. Also, an optimisation of the ancestral nodes was performed using TNT 1.5 software. In relation to the phylogenetic signal, both methods showed similar results: the presence of autocorrelation was detected in PC1 and PC2, while in PC3, PC4 and PC5 and in the size of the basicranium (CS), the absence of autocorrelation occurred. The most significant nodes (where there is autocorrelation) are the basal nodes ‘Ursidae’ and ‘Ursinae-Tremarctinae’. Within this last group, distinctive basicranium morphology is observed, being more conservative in Tremarctinae than in Ursinae. The differences between these subfamilies could be related to historical events involving varying food and environmental preferences. The high phylogenetic signal in the node Tremarctinae probably indicates that the basicranium configuration of these bears was obtained early in their evolutionary history. Finally, our results of the basicranium and skull length ratios indicate that in Tremarctinae, the basicranium size was not determined by phylogeny but instead by other factors, such as adaptive responses to climatic changes and competition with other carnivores.
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Vela-Vargas, I. Mauricio, Jeffrey P. Jorgenson, José F. González-Maya, and John L. Koprowski. "Tremarctos ornatus (Carnivora: Ursidae)." Mammalian Species 53, no. 1006 (July 15, 2021): 78–94. http://dx.doi.org/10.1093/mspecies/seab008.

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Abstract Tremarctos ornatus (F.G. Cuvier, 1825) is a tremarctine bear commonly known as the Andean bear. It is a medium-sized bear with black to dark red-brown pelage with dense, long, coarse fur; creamy white marks occur on the chin, neck, and chest, and often white to creamy marks occur on the face, around the muzzle, and eyes. It is distributed in the tropical Andes of Venezuela, Colombia, Ecuador, Perú, Bolivia, and northern Argentina in South America. T. ornatus is catalogued as “Vulnerable” (VU) by the International Union for Conservation of Nature and Natural Resources and is included in CITES Appendix I. Main threats include habitat loss and fragmentation, illegal killing, human–bear conflicts, and most likely climate change.
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Tedford, Richard H., and James Martin. "Plionarctos, a tremarctine bear (Ursidae: Carnivora) from western North America." Journal of Vertebrate Paleontology 21, no. 2 (July 20, 2001): 311–21. http://dx.doi.org/10.1671/0272-4634(2001)021[0311:patbuc]2.0.co;2.

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Soibelzon, Leopoldo H., Eduardo P. Tonni, and Mariano Bond. "The fossil record of South American short-faced bears (Ursidae, Tremarctinae)." Journal of South American Earth Sciences 20, no. 1-2 (October 2005): 105–13. http://dx.doi.org/10.1016/j.jsames.2005.07.005.

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Soibelzon, Leopoldo, and Viviana Tarantini. "Body mass estimation of extinct and extant South American bears (Ursidae, Tremarctinae)." Revista del Museo Argentino de Ciencias Naturales 11 (2009): 243–54. http://dx.doi.org/10.22179/revmacn.11.263.

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Soibelzon, Leopoldo H., and Ascanio D. Rincón. "The fossil record of the short-faced bears (Ursidae, Tremarctinae) from Venezuela. Systematic, biogeographic, and paleoecological implications." Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 244, no. 3 (June 1, 2007): 287–98. http://dx.doi.org/10.1127/0077-7749/2007/0244-0287.

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Дисертації з теми "Tremarctine bears"

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Bray, Sarah Catherine. "Mitochondrial DNA analysis of the evolution and genetic diversity of ancient and extinct bears." Thesis, 2011. http://hdl.handle.net/2440/66285.

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Mitochondrial phylogeographic analyses of modern populations can be used to make inferences about the impacts of the last glacial maximum (LGM) and anthropogenic disruption on late Pleistocene and Holocene ancestral populations. However, it is becoming more and more evident that ancient DNA studies greatly augment traditional mtDNA studies based only on extant lineages, and can reveal more complex scenarios than those hypothesised from modern data alone. Ancient DNA studies allow us to trace historic and ancient gene flow through time, giving a dynamic temporal and geographic understanding of genetic diversity. This is particularly informative when molecular data can be coupled with environmental or chronological information (such as radiocarbon dated specimens) allowing links to be made between climatic or anthropogenic disruptions and the genetic response of populations or species. This PhD research used ancient DNA techniques to investigate a number of biogeographic scenarios in relation to the phylogeography of brown bears (Ursus arctos) in Europe (Chapter 2- 4) and across the Eurasian continent (Chapter 5) throughout the Late Pleistocene and Holocene periods. Similarly, a study of the genetic diversity and phylogeography of the extinct giant short-faced bear (Arctodus simus) in North America was undertaken (Chapter 6) to provide a comparison with the dynamic phylogeographic history of contemporaneous Beringian brown bears (Barnes et al., 2002). Additionally, the deeper evolutionary history of the extinct Tremarctine bears was investigated using a molecular approach (Chapter 7) in an attempt to clarify the phylogenetic relationships of this lineage which have remained unresolved by morphological analyses. The research presented in this PhD thesis reinforces the important role that ancient DNA can play in understanding the mtDNA population dynamics and movements of taxa in response to environmental or anthropogenic changes through time. It stresses once again that the use of modern data alone is likely to lead to over-simplified or inaccurate views of past evolutionary history. Ancient DNA studies such as those presented here allow us to develop a more complex understanding of Quaternary phylogeographic patterns in a small number of taxa for which a sufficient number of samples can be obtained, and may guide future research to determine if similar patterns exist for other less-well studied species.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
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