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New specimens and neotype designation of Thisbemys brevicrista (Rodentia, Ischyromyidae) from the middle Eocene clarify the distinction between T. corrugatus and T. plicatus

Published online by Cambridge University Press:  05 May 2015

Deborah K. Anderson
Deborah K. Anderson*
Affiliation:
Department of Biology, Division of Natural Sciences, St. Norbert College, 100 Grant Street, De Pere, WI 54115, USA, (deborah.anderson@snc.edu)
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Abstract

Newly discovered mandibles and lower dentition of the middle Eocene rodent Thisbemys brevicrista from the Green River Basin, Wyoming, are the basis for a species re-diagnosis. Previously, only the upper dentition and a partial maxilla of T. brevicrista were known from Br3. New specimens from Br2 now include the lower molars, additional upper molars, and maxillary fragments including a partial zygomatic arch that preserves the relationship of the arch to the first upper molar. In addition, the presence of T. brevicrista at Br2 documents the co-existence of T. brevicrista with T. perditus, T. nini, T. plicatus, and T. corrugatus. Formerly, the latter two species were differentiated primarily using stratigraphy. Now, morphology and size can also be used. Thisbemys brevicrista is intermediate in size between T. plicatus and T. corrugatus, and can readily be distinguished from these species based on unique features of the upper and lower molars, which include an additional loph on the two anterior upper molars and a complete metalophid on m1-3. The original type specimen of T. brevicrista appears to be lost, thus a neotype is designated as part of the re-diagnosis. Discovery and description of the lower dentition and mandibles of T. brevicrista clarifies the alpha taxonomy of this species, and increases its utility for studies of phylogenetic relationships and for documenting Eocene mammalian diversity patterns.

Type
Articles
Information
Journal of Paleontology , Volume 89 , Issue 2 , March 2015 , pp. 318 - 330
Copyright
Copyright © 2015, The Paleontological Society 

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References

Anderson, D.K., 2008, Ischyromyidae, in Janis, C.M., Gunnell, G.F., and Uhen, M.D., eds., Evolution of Tertiary Mammals of North America: New York, Cambridge University Press, v. 2, p. 311–325.Google Scholar
Boyer, D.M., 2008, Relief index of second mandibular molars is a correlate of diet among prosimian primates and other euarchontan mammals: Journal of Human Evolution, v. 55, p. 1118–1137, doi:10.1016/j.jhevol.2008.08.002.Google Scholar
Boyer, D.M., Evans, A.R., and Jernvall, J., 2010, Evidence of dietary differentiation among Late Paleocene–Early Eocene plesiadapids (Mammalia, Primates): American Journal of Physical Anthropology, v. 142, p. 194–210, doi: 10.1002/ajpa.21211.Google Scholar
Bowditch, T.E., 1821, An Analysis of the Natural Classifications of Mammalia for the Use of Students and Travelers: Paris, J. Smith, 115 p.Google Scholar
Butler, P.M., 1985, Homologies of molar cusps and crests, and their bearing on assessments of rodent phylogeny, in Luckett, W.P., and Hartenberger, J.-L., eds., Evolutionary Relationships among Rodents: A Multidisciplinary Analysis: New York, Plenum Press, p. 381–401.Google Scholar
Cox, P.G., Rayfield, E.J., Fagan, M.J., Herrel, A., Pataky, T.C., and Jeffery, N., 2012, Functional evolution of the feeding system in rodents: PLoS ONE, v. 7, e36299, doi: 10.1371/journal.pone.0036299.Google Scholar
Eaton, J.G., 1982, Paleontology and correlation of Eocene volcanic rocks in the Carter Mountain area, Park County, southeastern Absaroka Range, Wyoming: University of Wyoming Contributions to Geology, v. 21, p. 153–194.Google Scholar
Gazin, C.L., 1976, Mammalian faunal zones of the Bridger Middle Eocene: Smithsonian Contributions to Paleontology, v. no. 26, p. 1–25.Google Scholar
Gingerich, P.D., 1979, Paleontology, phylogeny and classification: an example from the mammalian fossil record: Systematic Zoology, v. 28, p. 451–464, doi: 10.2307/sysbio/28.4.451.Google Scholar
Gould, S.J., 1975, On the scaling of tooth size in mammals: American Zoologist, v. 15, p. 351–362, doi: 10.1093/icb/15.2.353.Google Scholar
Gould, S.J., and Garwood, R.A., 1969, Levels of integration in mammalian dentitions: an analysis of correlations in Nesophontes micrus (Insectivora) and Oryzomys couesi (Rodentia): Evolution, v. 23, p. 276–300.Google Scholar
Gunnell, G.F., 1998, Mammalian fauna from the lower Bridger Formation (Bridger A, early Middle Eocene) of the southern Green River Basin, Wyoming: Contributions from the Museum of Paleontology, University of Michigan, v. 30, p. 83–130.Google Scholar
Gunnell, G.F., and Bartels, W.S., 1994, Early Bridgerian (middle Eocene) vertebrate paleontology and paleoecology of the southern Green River Basin, Wyoming: University of Wyoming Contributions to Geology, v. 30, p. 57–70.Google Scholar
Gunnell, G.F., Murphey, P.C., Stucky, R.K., Townsend, K.E.B., Robinson, P., Zonneveld, J.-P., and Bartels, W., 2009, Biostratigraphy and biochronology of the latest Wasatchian, Bridgerian, and Uintan North American Land Mammals “Ages”, in Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne: Flagstaff, Arizona, Museum of Northern Arizona Bulletin 65, p. 279–330.Google Scholar
Hunter, J.P., and Jernvall, J., 1995, The hypocone as a key innovation in mammalian evolution: Proceedings of the National Academy of Sciences, v. 92, p. 10718–10722.CrossRefGoogle ScholarPubMed
Kolbe, S.E., Lockwood, R., and Hunt, G., 2011, Does morphological variation buffer against extinction? A test using veneroid bivalves from the Plio-Pleistocene of Florida: Paleobiology, v. 37, p. 355–368, doi: 10.1666/09073.1.Google Scholar
Koyabu, D.B., Oshida, T., Dang, N.X., Can, D.N., Kimura, J., Sasaki, M., Motokawa, M., Son, N.T., Hayashida, A., Shintaku, Y., and Endo, H., 2009, Craniodental mechanics and the feeding ecology of two sympatric callosciurine squirrels in Vietnam: Journal of Zoology, v. 279, p. 372–380, doi: 10.1111/j.1469-7998.2009.00629.x.Google Scholar
Lazzari, V., Charles, C., Tafforeau, P., Vianey-Liaud, M., and Aguilar, J.-P., 2008, Mosaic convergence of rodent dentitions: PLoS ONE, v. 3, e3607, doi: 10.1371/journal.pone.0003607.Google Scholar
Lazzari, V., Aguilar, J.-P., and Michaux, J., 2010, Intraspecific variation and micro-macroevolution connection: illustration with the late Miocene genus Progonomys (Rodentia, Muridae): Paleobiology, v. 36, p. 641–657, doi: 10.1666/09046.1.Google Scholar
Linnaeus, C., 1758, Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis.Google Scholar
Mcgrew, P.O., Berman, J.E., Hecht, M.K., Hummel, J.M., Simpson, G.G., and Wood, A.E., 1959, The geology and paleontology of the Elk Mountain and Tabernacle Butte area, Wyoming: Bulletin American Museum of Natural History, v. 117, p. 117–176.Google Scholar
Mcgrew, P.O., and Sullivan, R., 1970, The stratigraphy and paleontology of Bridger A: University of Wyoming Contributions to Geology, v. 9, p. 66–85.Google Scholar
Miller, G.S., and Gidley, J.W., 1918, Synopsis of the supergeneric groups of rodents: Journal of the Washington Academy of Sciences 8, p. 431–448.Google Scholar
Murphey, P.C., and Evanoff, E., 2007, Stratigraphy, fossil distribution and depositional environments of the upper Bridger Formation (middle Eocene), southwestern Wyoming: Wyoming State Geological Survey Report of Investigation, no. 57, p. 1–96.Google Scholar
Norconk, M.A., Grafton, B.W., and Conklin-Brittain, N.L., 1998, Seed dispersal by neotropical seed predators: American Journal of Primatology, v. 45, p. 103–126.Google Scholar
Ostrander, G.E., 1986, A new species of the early Tertiary rodent Thisbemys: Transactions of the Kansas Academy of Science, v. 89, p. 45–48.Google Scholar
Pfennig, D.W., and Pfennig, K.S., 2012, Evolution’s Wedge: Competition and the Origins of Diversity: Berkeley, University of California Press, 303 p.Google Scholar
Renaud, S., Benammi, M., and Jaeger, J.-P., 1999, Morphological evolution of the murine rodent Paraethomys in response to climatic variations (Mio-Pleistocene of North Africa): Paleobiology, v. 25, p. 369–382, doi: 10.1666/0094-8373-25.3.369.CrossRefGoogle Scholar
Renaud, S., Michaux, J., Schmidt, D.N., Aguilar, J.-P., Mein, P., and Auffray, J.-C., 2005, Morphological evolution, ecological diversification and climate change in rodents: Proceedings of the Royal Society of London B: Biological Sciences, v. 272, p. 609–617, doi: 10.1098/rspb.2004.2992.Google Scholar
Reumer, J.W.F., 1995, The effect of paleoclimate on the evolution of the Soricidae (Mammalia, Insectivora), in Vrba, E., Denton, G., Partridge, T., and Burckle, L., eds., Paleoclimate and Evolution with Emphasis on Human Origins: New Haven, Yale University Press, p. 135–137.Google Scholar
Rose, K., and Koenigswald, W.V., 2007, The marmot-sized paramyid rodent Notoparamys costilloi from the Early Eocene of Wyoming, with comments on dental variation and occlusion in paramyids: Bulletin of Carnegie Museum of Natural History, no. 39, p. 111–125.Google Scholar
Rosenberger, A.L., and Kinzey, W.G., 1976, Functional patterns of molar occlusion in platyrrhine primates: American Journal of Physical Anthropology, v. 45, p. 281–298.Google Scholar
West, R.M., and Atkins, E.G., 1970, Additional middle Eocene (Bridgerian) mammals from Tabernacle Butte, Sublette County, Wyoming: American Museum of Novitates, no. 2404, p. 1–26.Google Scholar
West, R.M., and Hutchison, J.H., 1981, Paleontology and geology of the Bridger Formation, southern Green River Basin, southwestern Wyoming. part 6, The fauna and correlation of Bridger E: Contributions in Biology and Geology, Milwaukee Public Museum, no. 46, p. 1–8.Google Scholar
Wood, A.E., and Wilson, R.W., 1936, A suggested nomenclature for the cusps of the cheek teeth of rodents: Journal of Paleontology, v. 10, p. 388–391.Google Scholar
Wood, A.E., 1962, The Early Tertiary rodents of the family Paramyidae: Transactions of the American Philosophical Society, v. 52, p. 1–261.Google Scholar
Woodburne, M.O., Gunnell, G.F., and Stucky, R.K., 2009a, Climate directly influences Eocene mammal faunal dynamics in North America: Proceedings of the National Academy of Sciences, v. 106, p. 13399–13403, doi: 10.1073/pnas.0906802106.Google Scholar
Woodburne, M.O., Gunnell, G.F., and Stucky, R.K., 2009b, Land mammal faunas of North America: Rise and fall during the Early Eocene Climatic Optimum: Denver Museum of Nature and Science Annals, no. 1, p. 1–80.Google Scholar