Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America.
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.
Australian Centre for Ancient DNA, School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia kieren.mitchell@adelaide.edu.au.
Kieren J
http://orcid.org/0000-0002-3921-0262
KJ
Mitchell
Australian Centre for Ancient DNA, School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia Acute Leukaemia Laboratory, Centre for Cancer Biology, University of South Australia, Adelaide, South Australia 5000, Australia.
Sarah C
http://orcid.org/0000-0001-7067-4551
SC
Bray
Australian Centre for Ancient DNA, School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia Department of Biodiversity and Conservation, Institut Mediterrani d'Estudis Avançats (IMEDEA, CSIC-UIB), Illes Balears, Spain.
Pere
P
Bover
División Paleontología de Vertebrados, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Museo de La Plata, Argentina.
Leopoldo
L
Soibelzon
Department of Geosciences and Don Sundquist Center of Excellence in Paleontology, East Tennessee State University, Johnson City, TN 37614, USA.
Blaine W
BW
Schubert
Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de Anillaco (CRILAR), CONICET, La Rioja, Argentina.
Francisco
F
Prevosti
Centro de Estudios del Hombre Austral: Instituto de la Patagonia, Universidad de Magallanes, Punta Arenas, Chile.
Alfredo
A
Prieto
Centro de Estudios del Hombre Austral: Instituto de la Patagonia, Universidad de Magallanes, Punta Arenas, Chile.
Fabiana
F
Martin
Australian Centre for Ancient DNA, School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.
Jeremy J
JJ
Austin
Australian Centre for Ancient DNA, School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.
Alan
A
Cooper
D000818:Animals; D005075:Biological Evolution; D002677:Chile; D000072441:DNA, Ancient / Q000032:analysis*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005580:Fossils; D054629:Genome, Mitochondrial; D010802:Phylogeny; D001503:Ursidae / Q000145:classification / Q000235:genetics*
D000072441:DNA, Ancient; D004272:DNA, Mitochondrial
Ursidae; great American biotic interchange; molecular dating; palaeontology