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Juman MM, Millien V, Olson LE, Sargis EJ. Recent and rapid ecogeographical rule reversals in Northern Treeshrews. Sci Rep 2022; 12:19689. [PMID: 36446809 PMCID: PMC9708835 DOI: 10.1038/s41598-022-23774-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/04/2022] [Indexed: 11/30/2022] Open
Abstract
Two of the most-studied ecogeographical rules describe patterns of body size variation within species. Bergmann's rule predicts that individuals have larger body sizes in colder climates (typically at higher latitudes), and the island rule predicts that island populations of small-bodied species average larger in size than their mainland counterparts (insular gigantism). These rules are rarely tested in conjunction or assessed across space and time simultaneously. We investigated these patterns in the Northern Treeshrew (Tupaia belangeri) using museum specimens collected across a wide spatial and temporal range. Contrary to Bergmann's rule, size increases with temperature in T. belangeri, a signal that is highly consistent across space and time. We also show that these rules are intertwined: Bergmann's rule is reversed on the mainland but holds on islands, and therefore the island rule is upheld at higher, but not lower, latitudes. Moreover, we demonstrate a rapid reversal of both rules over time. The mechanism behind these inversions remains unclear, though temperature and precipitation are significant predictors of body size. Ecogeographical rules rely on the assumption of a constant relationship between size and the factors driving its variation. Our results highlight the need to question this assumption and reevaluate these rules in the context of accelerating and uneven climate change.
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Affiliation(s)
- Maya M. Juman
- grid.47100.320000000419368710Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT USA ,grid.70738.3b0000 0004 1936 981XDepartment of Mammalogy, University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK USA ,grid.5335.00000000121885934Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Virginie Millien
- grid.14709.3b0000 0004 1936 8649Redpath Museum, McGill University, Montreal, QC Canada
| | - Link E. Olson
- grid.70738.3b0000 0004 1936 981XDepartment of Mammalogy, University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK USA
| | - Eric J. Sargis
- grid.47100.320000000419368710Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT USA ,grid.47100.320000000419368710Department of Anthropology, Yale University, New Haven, CT USA ,grid.47100.320000000419368710Divisions of Vertebrate Zoology and Vertebrate Paleontology, Yale Peabody Museum of Natural History, New Haven, CT USA ,grid.47100.320000000419368710Yale Institute for Biospheric Studies, New Haven, CT USA
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Juman MM, Woodman N, Miller-Murthy A, Olson LE, Sargis EJ. Taxonomic boundaries in Lesser Treeshrews (Scandentia, Tupaiidae: Tupaia minor ). J Mammal 2022. [DOI: 10.1093/jmammal/gyac080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
The Lesser Treeshrew, Tupaia minor Günther, 1876, is a small mammal from Southeast Asia with four currently recognized subspecies: T. m. minor from Borneo; T. m. malaccana from the Malay Peninsula; T. m. humeralis from Sumatra; and T. m. sincepis from Singkep Island and Lingga Island. A fifth subspecies, T. m. caedis, was previously synonymized with T. m. minor; it was thought to occur in northern Borneo and on the nearby islands of Banggi and Balambangan. These subspecies were originally differentiated based on pelage color, a plastic feature that has proven to be an unreliable indicator of taxonomic boundaries in treeshrews and other mammals. To explore infraspecific variation among T. minor populations across the Malay Peninsula, Borneo, Sumatra, and smaller islands, we conducted multivariate analyses of morphometric data collected from the hands and skulls of museum specimens. Principal component and discriminant function analyses reveal limited differentiation in manus and skull proportions among populations of T. minor from different islands. We find no morphometric support for the recognition of the four allopatric subspecies and no support for the recognition of T. m. caedis as a separate subspecies on Borneo.
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Affiliation(s)
- Maya M Juman
- Department of Ecology and Evolutionary Biology, Yale University , New Haven, Connecticut 06520 , USA
| | - Neal Woodman
- U.S. Geological Survey, Eastern Ecological Science Center , Laurel, Maryland 20708 , USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, District of Columbia 20013 , USA
| | - Ananth Miller-Murthy
- Division of Vertebrate Zoology, Yale Peabody Museum of Natural History , New Haven, Connecticut 06520 , USA
| | - Link E Olson
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, District of Columbia 20013 , USA
- Department of Mammalogy, University of Alaska Museum, University of Alaska Fairbanks , Fairbanks, Alaska 99775 , USA
| | - Eric J Sargis
- Department of Ecology and Evolutionary Biology, Yale University , New Haven, Connecticut 06520 , USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, District of Columbia 20013 , USA
- Division of Vertebrate Zoology, Yale Peabody Museum of Natural History , New Haven, Connecticut 06520 , USA
- Department of Anthropology, Yale University , New Haven, Connecticut 06520 , USA
- Yale Institute for Biospheric Studies , New Haven, Connecticut 06520 , USA
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Hinckley A, Sanchez-Donoso I, Comas M, Camacho-Sanchez M, Hawkins MTR, Hasan NH, Leonard JA. Challenging ecogeographical rules: Phenotypic variation in the Mountain Treeshrew (Tupaia montana) along tropical elevational gradients. PLoS One 2022; 17:e0268213. [PMID: 35714073 PMCID: PMC9205479 DOI: 10.1371/journal.pone.0268213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/22/2022] [Indexed: 11/19/2022] Open
Abstract
Bergmann’s and Allen’s rules were defined to describe macroecological patterns across latitudinal gradients. Bergmann observed a positive association between body size and latitude for endothermic species while Allen described shorter appendages as latitude increases. Almost two centuries later, there is still ongoing discussion about these patterns. Temperature, the common variable in these two rules, varies predictably across both latitude and elevation. Although these rules have been assessed extensively in mammals across latitude, particularly in regions with strong seasonality, studies on tropical montane mammals are scarce. We here test for these patterns and assess the variation of several other locomotory, diet-associated, body condition, and thermoregulatory traits across elevation in the Mountain Treeshrew (Tupaia montana) on tropical mountains in Borneo. Based on morphological measurements from both the field and scientific collections, we found a complex pattern: Bergmann’s rule was not supported in our tropical mountain system, since skull length, body size, and weight decreased from the lowest elevations (<1000 m) to middle elevations (2000–2500 m), and then increased from middle elevations to highest elevations. Allen’s rule was supported for relative tail length, which decreased with elevation, but not for ear and hindfoot length, with the former remaining constant and the latter increasing with elevation. This evidence together with changes in presumed diet-related traits (rostrum length, zygomatic breadth and upper tooth row length) along elevation suggest that selective pressures other than temperature, are playing a more important role shaping the morphological variation across the distribution of the Mountain Treeshrew. Diet, food acquisition, predation pressure, and/or intra- and inter-specific competition, are some of the potential factors driving the phenotypic variation of this study system. The lack of variation in body condition might suggest local adaptation of this species across its elevational range, perhaps due to generalist foraging strategies. Finally, a highly significant temporal effect was detected in several traits but not in others, representing the first phenotypic variation temporal trends described on treeshrews.
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Affiliation(s)
- Arlo Hinckley
- Conservation & Evolutionary Genetics Group, Estación Biológica de Doñana-CSIC, Seville, Spain
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
- Departamento de Zoología, Universidad de Sevilla, Seville, Spain
- * E-mail: (AH); (JAL)
| | - Ines Sanchez-Donoso
- Conservation & Evolutionary Genetics Group, Estación Biológica de Doñana-CSIC, Seville, Spain
| | - Mar Comas
- Conservation & Evolutionary Genetics Group, Estación Biológica de Doñana-CSIC, Seville, Spain
- Departamento de Zoología, Universidad de Granada, Granada, Spain
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States of America
| | - Miguel Camacho-Sanchez
- Conservation & Evolutionary Genetics Group, Estación Biológica de Doñana-CSIC, Seville, Spain
- Instituto Andaluz de Investigación y Formación Agraria, Pesquera, Alimentaria y de la Producción Ecológica (IFAPA), Alcalá del Río, Seville, Spain
| | - Melissa T. R. Hawkins
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
| | - Noor Haliza Hasan
- Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Jennifer A. Leonard
- Conservation & Evolutionary Genetics Group, Estación Biológica de Doñana-CSIC, Seville, Spain
- * E-mail: (AH); (JAL)
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Theriot MK, Lanier HC, Olson LE. Harnessing natural history collections to detect trends in body‐size change as a response to warming: a critique and review of best practices. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Miranda K. Theriot
- Sam Noble Oklahoma Museum of Natural History, 2401 Chautauqua Ave Norman,, Oklahoma, 73072 USA
- Department of Biology University of Oklahoma 730 Van Vleet Oval, Room 314, Norman, Oklahoma 73019 USA
- University of Alaska Museum 1962 Yukon Dr, Fairbanks, AK 99775 USA
- Department of Biology and Wildlife University of Alaska Fairbanks 101 Murie 2090 Koyukuk Drive, Fairbanks, AK 99709 USA
| | - Hayley C. Lanier
- Sam Noble Oklahoma Museum of Natural History, 2401 Chautauqua Ave Norman,, Oklahoma, 73072 USA
- Department of Biology University of Oklahoma 730 Van Vleet Oval, Room 314, Norman, Oklahoma 73019 USA
| | - Link E. Olson
- University of Alaska Museum 1962 Yukon Dr, Fairbanks, AK 99775 USA
- Department of Biology and Wildlife University of Alaska Fairbanks 101 Murie 2090 Koyukuk Drive, Fairbanks, AK 99709 USA
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Skeletal Variation and Taxonomic Boundaries in the Pen-tailed Treeshrew (Scandentia: Ptilocercidae; Ptilocercus lowii Gray, 1848). J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09556-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Endo H, Nguyen TS, Nguyen DD, Sasaki M, Kimura J, Oshida T, Yago M, Ly NT, Nguyen TT, Motokawa M. Zoogeographical barriers causing discontinuous osteometrical variations in the northern treeshrew skulls. J Vet Med Sci 2021; 83:1534-1544. [PMID: 34380913 PMCID: PMC8569870 DOI: 10.1292/jvms.21-0322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Morphological variation of the skull was examined in the northern treeshrew
(Tupaia belangeri) from various localities across Southeast Asia.
Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct
morphological characteristics compared to other populations from Thailand and Laos, and
Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand
plots segregation in the scatteregrams of canonical discriminant analysis. Since the
skulls of the population from North Vietnam were morphologically similar to those form
central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of
Mekong River was not clearly confirmed. The population of the Kanchanaburi in western
Thailand is clearly smaller in size compared to the other populations. The southern border
of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani
Line. In the northern treeshrew, which is distributed from southern China to Bangladesh
and southern Thailand, we have detected osteometrical geographical variation driven by
geography. These results indicate that the skull morphology in the Tupaia
glis-belangeri complex distinctively differs in South Vietnam, western
Thailand, and southern Thailand. The zoogeographical barrier and factor separating these
districts are expected to clarify in the future.
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Affiliation(s)
- Hideki Endo
- The University Museum, The University of Tokyo
| | - Truong Son Nguyen
- Department of Vertebrate Zoology, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology
| | - Dinh Duy Nguyen
- Department of Vertebrate Zoology, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology
| | - Motoki Sasaki
- Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine
| | - Junpei Kimura
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University
| | - Tatsuo Oshida
- Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine
| | - Masaya Yago
- The University Museum, The University of Tokyo
| | - Ngoc Tu Ly
- Department of Vertebrate Zoology, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology
| | - Thi Tham Nguyen
- Faculty of Environmental Sciences, University of Science, Vietnam National University.,Central Institute for Natural Resources and Environmental Studies, Vietnam National University
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Juman MM, Woodman N, Olson LE, Sargis EJ. Ecogeographic variation and taxonomic boundaries in Large Treeshrews (Scandentia, Tupaiidae: Tupaia tana Raffles, 1821) from Southeast Asia. J Mammal 2021. [DOI: 10.1093/jmammal/gyab059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
The Large Treeshrew, Tupaia tana Raffles, 1821, is a small mammal (~205 g) from Southeast Asia with a complicated taxonomic history. Currently, 15 subspecies are recognized from Borneo, Sumatra, and smaller islands, and many were originally differentiated based on minor pelage differences and small sample sizes. We explored intraspecific variation in T. tana using quantitative osteological data obtained from the hands and skulls of museum specimens. Multivariate analyses reveal extensive overlap among T. tana populations in morphospace, indicating that the majority of currently recognized subspecies are not morphometrically distinct. In contrast, the separation between Bornean and Sumatran populations of T. tana is sufficient to recognize them as different subspecies. Comparisons of Bornean specimens to those on small, offshore islands reveal that the latter average smaller body size. This pattern is inconsistent with Foster’s island rule, which predicts that island populations of small mammals (< 5 kg) will average larger body size relative to mainland forms. A similar lack of support for ecogeographic rules has been noted in T. glis (Diard, 1820), suggesting that these “rules” are poor predictors of geographic variation in treeshrews.
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Affiliation(s)
- Maya M Juman
- Department of Ecology and Evolutionary Biology, Yale University , New Haven, CT , USA
| | - Neal Woodman
- U.S. Geological Survey, Eastern Ecological Science Center , Laurel, MD , USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Link E Olson
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
- Department of Mammalogy, University of Alaska Museum, University of Alaska Fairbanks , Fairbanks, AK , USA
| | - Eric J Sargis
- Department of Ecology and Evolutionary Biology, Yale University , New Haven, CT , USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
- Division of Vertebrate Zoology, Yale Peabody Museum of Natural History , New Haven, CT , USA
- Department of Anthropology, Yale University , New Haven, CT , USA
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Woodman N, Miller-Murthy A, Olson LE, Sargis EJ. The limitations of external measurements for aging small mammals: the cautionary example of the Lesser Treeshrew (Scandentia: Tupaiidae: Tupaia minor Günther, 1876). J Mammal 2021. [DOI: 10.1093/jmammal/gyab055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Age is a basic demographic characteristic vital to studies of mammalian social organization, population dynamics, and behavior. To eliminate potentially confounding ontogenetic variation, morphological comparisons among populations of mammals typically are limited to mature individuals (i.e., those assumed to have ceased most somatic growth). In our morphometric studies of treeshrews (Scandentia), adult individuals are defined by the presence of fully erupted permanent dentition, a common criterion in specimen-based mammalogy. In a number of cases, however, we have had poorly sampled populations of interest in which there were potentially useful specimens that could not be included in samples because they lacked associated skulls. Such specimens typically are associated with external body and weight measurements recorded by the original collectors, and we sought to determine whether these data could be used successfully as a proxy for age or at least to establish maturity. We analyzed four traditional external dimensions (head-and-body length, tail length, hind foot length, and ear length) and weight associated with 103 specimens from two allopatric populations of the Lesser Treeshrew (Tupaia minor Günther, 1876) from Peninsular Malaysia and from Borneo, which we treated as separate samples (populations). Individuals were assigned to one of eight age categories based on dental eruption stage, and measurements were compared among groups. In general, mean sizes of infants and subadults were smaller than those of adults, but the majority of subadults fell within the range of variation of adults. The large overlap among infants, subadults, and adults in external measurements and weight indicates that such measures are poor proxies for age in this species, probably for treeshrews in general, and possibly for other small mammals. This has significant implications for any investigation wherein relative age of individuals in a given population is an important consideration.
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Affiliation(s)
- Neal Woodman
- U.S. Geological Survey, Eastern Ecological Science Center, Laurel, MD, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Ananth Miller-Murthy
- Division of Vertebrate Zoology, Yale Peabody Museum of Natural History, New Haven, CT, USA
| | - Link E Olson
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Eric J Sargis
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Division of Vertebrate Zoology, Yale Peabody Museum of Natural History, New Haven, CT, USA
- Department of Anthropology, Yale University, New Haven, CT, USA
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