tree squirrel distribution

Squirrels. Tree squirrels have long, bushy tails, sharp claws and large ears. Speciation plots of Sciurini. This sciurid was interpreted as an arboreal form similar to Sciurus and is the ancestor of both flying squirrels (Pteromyini) and ground squirrels (multiple tribes). The number of transitions (s) and transversions (v) in the mitochondrial genome dataset is plotted against the F84 distances. found in the oriental region of the world. 20, 33503366. National Science Foundation Since their diets consist of mainly fruits and seeds, squirrels become very useful in seed dispersal. We applied a single nucleotide substitution model (GTR) with a gamma category of 4 to our dataset and implemented a lognormal relaxed clock with a Yule tree prior. We do not consider sexual differences (i.e. Emry, R. J., Korth, W. W., and Bell, M. A. The LTT plot indicated an initial low and constant net diversification rate from about 14 to 10.5 Mya, followed by a moderate increase from 10.5 to 5 Mya, and an acceleration on the diversification rate from 5 Mya to the present (Figure 3A). similar to the area of Puerto Rico or Kosovo for comparison) of national relevance . Sci. Accessed These are the most common species, often seen running across tree branches and climbing trees. The sciurid breeding season is marked by the development of male testes and sexual swelling of the females, as is common in many mammals. The skull has an broad, tilted zygomatic plate that serves as the attachment point for the lateral branch of the masseter muscle. Squirrel pelts were also once used as a form of currency. Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. All sciurids give birth to their young in a nest. Cenozoic South American land mammal ages: correlation to global geochronologies, in Geochronology, Time Scales and Global Stratigraphic Correlation, eds W. Berggren, D. V. Kent, M.-P. Aubry, and J. Hardenbol (Tulsa, OK: Society of Economic Paleontologists and Mineralogists), 317334. Wilson, D., D. Reeder. Ground squirrels tend to have large broad forefeet, with the middle digit being the longest, short, stout limbs used for digging, and short tails. In other words, India and southeast Asia. PLoS One 12:e0187969. GenBank accession numbers for all complete mitogenomes are provided in the Supplementary Table S1. The recent mammals of the Neotropical region: a zoogeographic and ecological review, in Evolution, Mammals and Southern Continents, eds A. Keast, F. C. Erk, and B. P. Glass (Albany, NY: State University of New York Press), 311431. An area including both North America and Eurasia was estimated with the second highest probability of occurrence for the ancestor of Sciurini (30.6%; Supplementary Table S2). doi: 10.11646/zootaxa.3782.1.1, ODea, A., Lessios, H. A., Coates, A. G., Eytan, R. I., Restrepo-Moreno, S. A., Cione, A. L., et al. Neotrop. The events in the Miocene were: the diversification of the Borneo endemic species Rheithrosciurus macrotis, the Eurasian Sciurus anomalus, and the North American Neosciurus carolinensis. Paleobiology 5, 126132. Finally, we tested the hypothesis that tree squirrels represent a rapid-diversified radiation (Roth and Mercer, 2008) by estimating speciation rates and investigating diversification rate fluctuations through time. Lack of accurate information on populations and threats is another important factor in sciurid conservation generally. (2012). doi: 10.1111/j.1463-6409.2011.00528.x, Penerov, P., Moravec, J. C., and Martnkov, N. (2015). Patterns of Body and Tail Length and Body Mass in Sciuridae. Moreover, our analysis yielded a mean diversification rate around 0.29 for tree squirrels, which is slightly higher than the estimate of Zelditch et al. (On-line). Paleoceanography 23, 115. at http://proquest.umi.com.proxy.lib.umich.edu/pqdweb?did=1559964161&sid=1&Fmt=6&clientId=17822&RQT=309&VName=PQD. These tree squirrels usually feed on fruits, nuts, and other vegetation. Biol. (2019). Rev. Proc. The Bayesian approach, however, showed a pattern of constant speciation rate through time, with no inflection point and with a slight decrease on the magnitude of speciation over time (Figure 3B). Tree squirrels often have lighter coloration on the ventral side compared to the dorsal, allowing them to blend in with the light sky to a predator that is looking at the squirrel from below and at to blend in with the dark ground when being stalked by an aerial predator. Tamiasciurus hudsonicus. (2015). Sci. 64, 10741088. The currently valid species of tree squirrels not included in this study are: Tamiasciurus fremonti sensu Hope et al. Colors in key boxes and map correspond to coloring of boxes within the tree (most probable ancestral ranges) and at terminals (current distribution of species). Genet. Inferring the mammal tree: species-level sets of phylogenies for questions in ecology, evolution, and conservation. Sci. This is in contrast to previous findings that suggested that the ancestors of this tribe occupied Eurasia. For squirrels that hibernate, mothers must wean their young in enough time to gain winter weight for hibernation. However, we observed a peak of lineage accumulation since the beginning of the Pliocene, which coincides with the Neotropical invasion, followed by a rapid diversification in this area. Long, cold winters and short, wet summers. The ancestral range estimation of the tribe Sciurini on a global scale (Figure 1) allows the inference of seven founder-event speciation and three anagenetic dispersals, while it does not indicate the occurrence of vicariance events during the evolutionary history of tree squirrels (see Supplementary Figures 3, 4). Animal Diversity Web. Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. 17:e3000494. Squirrels may carry diseases, such as plague, which can be transmitted to humans and domestic animals. Distribution The tree squirrel is Available through the USA, as well as in some parts of Canada. 2003. FIGURE S1 | Nucleotide substitution saturation plot. Therefore, this is the most comprehensive study investigating the biogeographic history of the tribe Sciurini, both in number of species and geographic coverage. "Tree squirrels" is an all encompassing term for several species, including fox squirrels, gray squirrels, flying squirrels and pine squirrels. Referring to a burrowing life-style or behavior, specialized for digging or burrowing. Abreu-Jr, E. F., Pavan, S. E., Tsuchiya, M. T. N., Wilson, D. E., Percequillo, A. R., and Maldonado, J. E. (2020). This region was also the ancestral range of four genera: Microsciurus and Syntheosciurus (composed of Central and South American species), Leptosciurus (composed of species occupying mainly the northwestern portion of South America), and Simosciurus (composed of two species occurring in the coast of Ecuador and Peru). We used as outgroup two representatives of the tribe Pteromyini (the sister-tribe of Sciurini): Glaucomys volans (USNM 569823) and Hylopetes phayrei (USNM 584420). The GABI is one of the most significant events of transcontinental fauna dispersal that occurred during the temporal window from the late Pliocene to the late Pleistocene, wherein several mammal lineages migrated from North America to South America and the other way around (Simpson, 1983; Stehli and Webb, 1985; Woodburne, 2010). Within the mainly Central American radiation, a founder-event speciation is inferred, leading to the colonization of the Mexican transition zone and Mesoamerican dominion by the ancestor of the genus Echinosciurus around 3.7 Mya. Dispersal-vicariance analysis: a new approach to the quantification of historical biogeography. In this way, the number of species that went extinct possibly equalized the evident increase in species accumulation since the Pliocene and, therefore, the number of species maintained over time is similar to the number of extinct species. The analysis was conducted by running 600 million generations of Markov chain Monte Carlo (MCMC), sampling every 60,000 generations. Fire and grazing are important in the long-term maintenance of grasslands. Our estimates suggested that the most recent common ancestor of Sciurini probably inhabited exclusively North America (near 60% of probability). Salt limits the ability of plants to take up water through their roots. Sciurids can be found at high elevations, such as the Himalayan marmots (Marmota himalaya), which are found at elevations up to 5000 meters. During the Pliocene, the great majority of speciation events took place in South America, where ten species (from all genera) originated; in Central America five species originated (also from all genera) and in North America only one speciation event occurred (within the genus Hesperosciurus). Disclaimer: Synapomorphy of the Bilateria. The large clade including exclusively Neotropical taxa (marked with a black star in Figure 1) originated with highest probability in South America at 5.9 Mya (5.26.5). Foreign and other copyrights may apply. (2020), as we employed the same taxa and data source. (2012). Museum Nat. Regarding speciation events generating the 43 extant species of Sciurini analyzed here, three species originated in the Miocene, 17 in the Pliocene, and 23 in the Pleistocene. doi: 10.1111/j.1365-294X.2011.05184.x, Costa, L. P. (2003). Northeastern Naturalist, 11: 123-137. Convergent in birds. The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fevo.2020.00230/full#supplementary-material. 67, 901904. Proc. Rev. 35, 15501552. For rare species such as snow leopards and northern spotted owls, squirrels are an essential part of the diet. The CDS matrix was aligned using MUSCLE (Edgar, 2004), with up to eight interactions. Tree squirrels (Sciurinae, Sciurini) represent a diverse radiation that successfully colonized forested landscapes of Europe, Asia and the Americas during the Miocene and Pliocene ( Mercer and Roth, 2003; Penerov et al., 2015 ). (2020), that included samples from 40 of the 43 recognized species of Sciurini (sensu Thorington et al., 2012; Vivo and Carmignotto, 2015; Hope et al., 2016), revealed an underestimated diversity on the genus and species group levels within the tribe and clarified several important points with regards to the phylogenetic relationships and systematics of tree squirrels. Squirrels are largely herbivorous, eating seeds, nuts, fruits, fungi, and other plant matter; however, insects, eggs and the occasional small vertebrate may be part of the diverse diet of these animals. Proc. A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. Accessed doi: 10.3758/BF03206482, Woodburne, M. O. Figure 4. at http://animals.jrank.org/pages/3363/Squirrels-Relatives-Sciuridae.html. This is not only because seeds are left in the feces of these animals but also because of the caching habits of many squirrels. MUSCLE: multiple sequence alignment with high accuracy and high throughput. The ancestors of the remaining South American genera (Guerlinguetus, Microsciurus, Hadrosciurus) occupied areas east of the Andes with highest probability. Generally, females are widely dispersed and males do not defend a territory, but this behavior varies. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Over the years, many more rearrangements of tribes and subfamilies occurred until Sciuridae was believed to only include two subfamilies, Sciurinae (tree and ground squirrels) and Pteromyini (flying squirrels), and ten tribes (Callosciurini, Funambulini, Marmotini, Microsciurini, Protoxerini, Ratufini, Sciurillini, Sciurini, Tamiasciurini, and Xerini). They vary greatly in geographic range and habitat. Tree squirrels (Sciurinae, Sciurini) represent a diverse radiation that successfully colonized Europe, Asia and the Americas during the Miocene-Pliocene, but information on their evolutionary history remains unclear. Syst. We estimated the ancestral range of the phylogenetic nodes and investigated the historical events (e.g., vicariance, dispersal) that might be evoked to explain the diversification pattern of the tribe Sciurini. They are also known for their caching and hoarding behaviors, which requires learning and remembering landmarks in complex environments. Geol. The most endangered sciurid is the Vancouver Marmot (Marmota vancouverensis), consisting of only an estimated 35 individuals in the wild as of 2004. Abundance and Distribution The ranges of many of these species overlap and several may be found coexisting. However, many squirrels do not live past their first year of life in the wild. The mean speciation rate of Sciurini was 0.29. Evol. Pleistocene climatic fluctuations were probably a determining factor in the diversification process within North American lineages, for instance across the genera Tamiasciurus (see Arbogast et al., 2001; Chavez et al., 2011) and Parasciurus. Its genus, Cynomys, derives from the Greek for "dog mouse" ( kun, kunos . at http://animaldiversity.ummz.umich.edu/site/accounts/information/Sciuromorpha.html. Taxon Information Our results corroborate the date of origin of the tribe Sciurini around 14 Mya (13.415.5) but suggest that their ancestral area was most likely in North America. These results suggest that vicariance was not a main driver of the diversification processes of tree squirrels at either global or local (Neotropical) scales (but extinctions might mask instances of vicariance; see discussion below). Acad. The founder events (i.e., a jump of a lineage to a new area of occurrence outside of the ancestral range of the node; Matzke, 2013) were inferred for the ancestors of (1) the genus Rheithrosciurus from North America to Borneo, (2) the Eurasian genus Sciurus from North America to the Palearctic region, (3) the large Neotropical radiation from North America to South America, (4) the Central American clade from South America to Central America, (5) the clade Parasciurus alleni + P. oculatus from North America to Central America, (6) Parasciurus nayaritensis from North America to Central America, and (7) Microsciurus species 1 from Central America to South America. Results of BAMM analysis were processed and visualized using the R package BAMMtools (Rabosky et al., 2014). Boston, MA: Springer US. Biol. Jaramillo, C., Montes, C., Cardona, A., Silvestro, D., Antonelli, A., and Bacon, C. D. (2017). Many ground and tree squirrels commonly participate in bark stripping where they pull the bark off of trees to get to the tissue underneath. Biol. doi: 10.1093/sysbio/46.1.195. Theoretical and practical concerns in the analysis of multi-rate diversification models. Classification, To cite this page: His dominance is determined by his ability to keep close proximity both during and between mating chases. Automatic detection of key innovations, rate shifts, and diversity-dependence on phylogenetic trees. Science 339, 7478. The origin of Microsciurus dated to 3.2 Mya (2.53.7) and the origin of Hadrosciurus was estimated to 3.9 Mya (3.64.9). Squirrel populations periodically rise and fall. Bras. The founder-event speciation corresponds to the jump of the ancestors of (1) the genus Echinosciurus from the Pacific dominion to the Mexican transition zone and Mesoamerican dominion, (2) the genera Guerlinguetus, Microsciurus and Hadrosciurus from the Pacific dominion to the Boreal Brazilian dominion, (3) (Guerlinguetus aestuans b, (G. aestuans c, G. brasiliensis) from the Boreal Brazilian dominion to the South Brazilian dominion, and (4) (Guerlinguetus aestuans c, G. brasiliensis) from the South Brazilian dominion to Boreal Brazilian, South-eastern Amazon, and Parana dominions. "many forms." (2015) estimated a more restricted ancestral range of Sciurini, confined to the Palearctic region. Voucher acronyms refer to the following scientific collections: American Museum of Natural History, United States (AMNH); Field Museum of Natural History, United States (FMNH); University of Kansas Natural History Museum, United States (KU); Museu Nacional da Universidade Federal do Rio de Janeiro, Brazil (MN); Museu Paraense Emilio Goeldi, Brazil (MPEG); Museum of Southwestern Biology, University of New Mexico, United States (MSB); Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Peru (MUSM); Museum of Vertebrate Zoology, University of California, United States (MVZ); Smithsonian National Museum of Natural History, United States (USNM). (Macdonald, 1984; Thorington and Ferrell, 2006). This period of rapid inflation on the number of lineages, along the Pliocene and Pleistocene, coincides with the South American invasion and colonization by tree squirrels (Figure 3A; red star). scrub forests develop in areas that experience dry seasons. Splendid Isolation: the Curious History of South American Mammals. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia. Brown, E.; A. Peri and N. Santarosa 2014. Emily McBride Brown (author), University of Michigan-Ann Arbor, Alexandra Michelle Peri (author), University of Michigan-Ann Arbor, Nicole Ann Santarosa (author), University of Michigan-Ann Arbor, Tanya Dewey (editor), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor. In cases of unviability to examine vouchers, original museum identifications were accepted if (i) those identifications correspond to the known geographic distribution of the taxon in question, and (ii) phylogenetic analyses of their DNA sequences were consistent with the museum identification. Received: 31 January 2020; Accepted: 23 June 2020;Published: 23 July 2020. The models with best fitting scores on each biogeographic analysis are distinct in their criteria, as one detects vicariant events (DEC) and the other (BAYAREALIKE) does not (Matzke, 2013). Our biogeographic analyses focused on Neotropical Sciurini suggested with highest probability (92.2%) that this large clade originated in the northwestern portion of South America in the Pacific dominion (Figure 2; Supplementary Table S3). Gent. Sciurids vary in size from very small, like African pygmy squirrels (Myosciurus pumilio, approximately 10 g), to substantially large, such as Alpine marmots (Marmota marmota, 3 to 8 kg). Anderson, S., J. Jones. Biol. Our analyses revealed a mostly constant (slightly decreasing) speciation rate through time for the tribe Sciurini. Net Industries. Squirrels are members of the family Sciuridae (/ s j u r d e,-d i /), a family that includes small or medium-size rodents.The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels.Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. This work was supported by the Conselho Nacional de Desenvolvimento Cientfico e Tecnolgico through a doctoral fellowships to EA-J (147145/2016-3, 203692/2017-9, and 165553/2017-0) and through a productivity scholarship to AP (304156/2019-1); by the American Society of Mammalogists through the Latin American Student Field Research Award to EA-J, providing support for a field expedition to the Rio Purus, BR; by the American Museum of Natural History through a Collection Study Grant, allowing EA-J to collect morphological data from tree squirrels housed at the AMNH; by the Smithsonian Institution through postdoctoral fellowships to SP and MT (Smithsonian Womens Committee), and through research funds provided to SP, MT, DW, and JM, covering costs associated to laboratory procedures and DNA sequencing; by the National Geographic Society through an Explorers Grant to SP (NGS-381R-18), providing support to visit and collect samples housed at the MUSM and for a field expedition to Parque Nacional del Rio Abiseo, PE, and through Support for Women + Dependent Care to SP (NGS 3758), allowing her to visit and collect additional data in North American museums; and by the Fundao de Amparo Pesquisa do Estado de So Paulo to AP (09/16009-1), providing support for several field expeditions to the Amazon, BR. Their habitat can range from one to one-hundred acres depending on availability of food. Front. (Gurnell, 1987; Thorington and Ferrell, 2006), Squirrels are hunted for their meat and pelts. Australia and United Kingdom: CSIRO Publishing and CABI Publishing. the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south. Evol. Evol. EA-J wrote the manuscript with contributions from SP, MT, DW, AP, JM. Breeding biology and seasonal capture success of northern flying; squirrels and red squirrels in southern new brunswick. Their tails, while fully furred, generally are not as bushy as those of tree squirrels. AIC model selection using Akaike weights. Flying squirrels have a furred membrane (patagium) extending between the wrist and ankle that allows them to glide between trees. 5, 701707. (2017). A research project at the Institute of Arctic Biology at the University of Alaska, Fairbanks has been studying hibernation in arctic ground squirrels to learn more about strokes, heart attacks, and neurodegenerative diseases in humans caused by reduced blood flow. (Hayssen, 2008b; Thorington and Ferrell, 2006; Vernes, 2004), Gestation ranges from 29 to 65 days, depending on the size of the species, with smaller squirrels having shorter gestation periods. doi: 10.1007/978-1-4684-9181-4, Steppan, S. J., Adkins, R. M., and Anderson, J. January 28, 2009 Previous biogeographic analyses have included up to 28 Sciurini species, and less than a third of South American tree squirrel species (Penerov and Martnkov, 2012; Penerov et al., 2015). Methods Ecol. doi: 10.1073/pnas.1514719112, Maestri, R., Upham, N. S., and Patterson, B. D. (2019). Mamm. February 02, 2009 In summary, the majority of the cladogenetic events observed for Neotropical tree squirrels took place in the northern portion of South America and southern Central America during the Pliocene. (2020), with all nodes strongly supported (PP 0.98), excepted by the node of the genus Echinosciurus, which did not receive a significant support (PP < 0.95). It seems that the Central and South American lineages rapidly adapted to the new (and perhaps vacant) environments and experienced explosive diversification. 11, 192196. (2019), supporting a more recent date around 14 Mya compared to the estimation of Zelditch et al. At least two main distinct spatiotemporal routes have been proposed between the Amazon and the Atlantic Forest (Costa, 2003; Batalha-Filho et al., 2013; Ledo and Colli, 2017): older (middle to late Miocene) connections between southeastern Atlantic Forest and western Amazonia (the SE-NW bridge), and younger (Pliocene and Pleistocene) connections across northeastern Brazil (the NE bridge). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes). Evolution 69, 12841300. After the female accepts a particular male, copulation ensues, and the mating chase continues, allowing for multiple copulations for both males and females. 44, 170. Simpson, G. G. (1983). Patterson, B., and Pascual, R. (1972). Sciurids have three basic morphologies: ground squirrel, tree squirrel, and flying squirrel forms. EA-J analyzed the data. First North American fossil monkey and early Miocene tropical biotic interchange. The Amphibians and Reptiles of Costa Rica: A Herpetofauna between Two Continents, between Two Seas. Journal of Mammalogy, 3: 89-91. Quaterly Rev. doi: 10.1007/s10336-012-0866-7, Bloch, J. I., Woodruff, E. D., Wood, A. R., Rincon, A. F., Harrington, A. R., Morgan, G. S., et al. Sci. The major South American radiation is slightly older than the Central American one, with its date of origin estimated to around 5 Mya. U.S.A. 112:E5766. "Sciuridae. Accessed Vegetation is typically sparse, though spectacular blooms may occur following rain. (2017). DEla, G. (2000). (2013). breeding is confined to a particular season, reproduction that includes combining the genetic contribution of two individuals, a male and a female. The diversification and colonization of South America by the Neotropical pygmy squirrels are enigmatic pieces on the evolutionary history of this group. "Sciuridae" (On-line), Animal Diversity Web. at http://www.reference-global.com.proxy.lib.umich.edu/doi/pdf/10.1515/MAMM.2008.049. ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates. ("The IUCN Red List of Threatened Species", 2008; Gurnell, 1987; Jansa and Myers, 2000; Lurz, 2011; Steppan and Hamm, 2006; Thorington and Ferrell, 2006), Squirrels are found worldwide, native to all terrestrial regions with the exception of Australia, Madagascar, southern South America, Antarctica, Greenland, many oceanic islands, and certain desert regions such as the Sahara. Some groups of sigmodontine rodents also had their origin estimated to be in the late Miocene or Pliocene in northern South America, suggesting that this region has played an important role on the origin and diversification of forest rodents (Maestri et al., 2019). 12:88. doi: 10.1186/1471-2148-12-88, Flynn, J. J., and Swisher, C. C. III (1995). They have small infraorbital foramena that is not enlarged to transmit muscle as it is in myomorphous (mice and rats) and hystricomorphous (cavys and guinea pigs) rodents. This new taxonomic proposal suggested a diversity of 46 species within Sciurini which were tentatively organized in 14 genera coined by previous authors (see Abreu-Jr et al., 2020). Vibrissae, which are important for tactical stimuli, are found all over the body by the nose, cheek, eye, chin, wrist, feet, and outside of the legs. February 15, 2009 PLoS Comput. Evol. Version 13 May 2006" Nuclear DNA Phylogeny of the Squirrels (Mammalia:Rodentia) and the Evolution of Arboreality from c-myc and RAG1. Appearance of an early closure of the isthmus of Panama is the product of biased inclusion of data in the metaanalysis. Reig, O. Neotropical Rainforest Mammals: a Field Guide, Second Edn. The time-scaled topology provided by BEAST with only one individual per species was used as the input tree. a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter). Nowak, R. 1991. The South American continent has a history of major geological (such as the Andes uplift and the Amazon basin formation) and climatic (such as the Pleistocene climate fluctuations) changes that occurred in the past 10 million years. This is in contrast to previous findings that suggested that the ancestors of this tribe originated in Eurasia or in a large area that included Eurasia and North America (Penerov and Martnkov, 2012; Penerov et al., 2015; Rocha et al., 2016). (2010). February 03, 2009 Many squirrel species cache or hoard food as well. Description Tree squirrels are comparatively larger in size. Scr. Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels". Bull. Evolutionary history of tree squirrels (Rodentia, Sciurini) based on multilocus phylogeny reconstruction. We incorporated a sampling frequency of 0.93, considering that we have sampled about 93% of the extant species of Sciurini (43 out of the 46 putative species; Abreu-Jr et al., 2020). Upham, N. S., Esselstyn, J. Tree squirrels are found throughout the world. In summary, diversification events generating the major lineages from North America and Eurasia took place in the mid-late Miocene, whereas most speciation events involving extant species in those lineages occurred in the Pleistocene (Figure 1). Baltimore, Maryland: The Johns Hopkins University Press. 20, 125. 238, 195. Figure 1. 5, 242248. Strait arrows denote anagenetic dispersal events and curved arrows designate founder-event speciation (jump). Ancestral ranges for Sciurini estimated by DEC + J model in the global scale analysis are illustrated. doi: 10.1038/16446, Marko, P. B., Eytan, R. I., and Knowlton, N. (2015). Adv. February 01, 2009 Zool. Figure 2. These massive geological changes produced a great variety of new ecosystems in South America that favored the diversification of many groups of organisms. Tree squirrels are also very agile in maneuvering through the trees. Walker's Mammals of the World 5th Edition, Volume I. Baltimore and London: The Johns Hopkins University Press. Remarkably, our results indicate that tree squirrels entered South America at an earlier date than previously estimated. (2010). Tree squirrels (Sciurinae, Sciurini) represent a diverse radiation that successfully colonized forested landscapes of Europe, Asia and the Americas during the Miocene and Pliocene (Mercer and Roth, 2003; Penerov et al., 2015). Within the genera Microsciurus and Hadrosciurus, most species remained restricted to the Amazon basin and adjacent areas (along Boreal Brazilian and South Brazilian dominions). African tree squirrels tend to be born at larger birth weights and have relatively shorter times to independence. doi: 10.1111/evo.12642, Keywords: ancestral range, founder-event speciation, Isthmus of Panama, mitogenome, Neotropics, Sciurini, Citation: Abreu-Jr EF, Pavan SE, Tsuchiya MTN, Wilson DE, Percequillo AR and Maldonado JE (2020) Spatiotemporal Diversification of Tree Squirrels: Is the South American Invasion and Speciation Really That Recent and Fast?

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