A new species of big-eared climbing rat, genus Ototylomys (Cricetidae: Tylomyinae), from Chiapas, Mexico

Calvin A. Porter, Nia E. Beasley, Nicté Ordóñez-Garza, Laramie L. Lindsey, Duke S. Rogers, Nicole Lewis-Rogers, Jack W. Sites, Robert D. Bradley

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5 Scopus citations


An allopatric population of big-eared climbing rats (Ototylomys) from the Northern Highlands of Chiapas, Mexico, is described as a new species. The new taxon is part of a unique montane rainforest community that includes several other endemic species in the limited geographic range between the Río Grijalva and the Central Depression of Chiapas. Several cranial, external, and molecular characters distinguish this new species of big-eared climbing rat from its more widely distributed congener, Ototylomys phyllotis. We performed principal component and discriminate function analyses of cranial measurements, and found that specimens of the new species consistently could be distinguished from other Ototylomys with strong statistical support. Compared withexemplars of Ototylomys from elsewhere in their range, the new species possesses a karyotype that differs by 3 additional biarmed chromosome pairs, is fixed or nearly fixed for distinct electromorphs at 12 allozyme loci, and the mean genetic distance exceeds 14%, based on comparisons of the mitochondrial cytochrome b gene between the new species of Ototylomys and representatives of O. phyllotis. The restricted distribution in montane karst rainforest suggests that the species and its habitat may be a matter of conservation concern. Una población alopátrica de rata orejuda trepadora (Ototylomys) de las Tierras Altas del Norte de Chiapas, México se describe como una nueva especie. El nuevo taxón es parte de una comunidad única de bosque lluvioso montano que incluye varias especies endémicas en el área de distribución geográfica limitada entre el Río Grijalva y la Depresión Central de Chiapas. Varios caracteres craneales, externos, y moleculares distinguen la nueva rata orejuda trepadora de su congénere más ampliamente distribuido, Ototylomys phyllotis. Se realizaron análisis de componentes principales y de función discriminante de los caracteres craneales, y se encontró que los especímenes de La Pera fueron consistentemente distinguidos de otros Ototylomys con un fuerte soporte estadístico. En comparación con ejemplares de Ototylomys del rango, la nueva especie posee un cariotipo que difiere por 3 pares adicionales de cromosomas biarmados, está fijo o casi fijo por distintos electromorfos en 12 loci alozímicos. Adicionalmente, la media de la distancia genética comparada del gen mitochondrial citocromo b entre la nueva especie de Ototylomys y representantes de O. phyllotis, excede el 14%. La distribución restringida en el bosque lluvioso montano kárstico sugiere que la especie y su hábitat pueden ser de importancia para la conservación.

Original languageEnglish (US)
Pages (from-to)1310-1329
Number of pages20
JournalJournal of Mammalogy
Issue number5
StatePublished - Oct 1 2017
Externally publishedYes

Bibliographical note

Funding Information:
We acknowledge M. D. Engstrom for originally recognizing the new species. Specimens of Ototylomys were collected by numerous field biologists including the following: E. A. Arellano, B. Baker, M. Baker, R. H. Baker, A. Pérez Barrios, H. Bolig, D. Dennett, R. C. Dowler, N. D. Durish, M. D. Engstrom, D. A. Good, J. D. Hanson, E. J. Heske, M. C. Haynie, D. G. Huckaby, L. K. Longhofer, A. B. McPherson, F. Mendez-H, R. Mercado Vallejo, J. C. Morales, L. A. Ruedas, S. M. Russell, G. Schave, C. A. Schmidt, R. Sohn, E. Stern, J. R. Suchecki, P. K. Tucker, and R. G. Webb. G. Martin assisted with data analysis. We thank the following for specimen loans or access to collections: C. J. Conroy and J. L. Patton (MVZ); J. A. Esselstyn (LSUMZ); H. Garner (TTU); J. E. Light and H. Prestridge (BRTC); R. C. Dowler and M. A. Revelez (ASNHC); C. Schmidt (FHSM); L. Abraczinskas and B. Lundrigan (MSU); J. P. Dines (LACM); and V. Mathis (UF). A. B. Baird assisted in determining voucher numbers. The allozyme work was funded by a 1984 grant to CAP from the Associated Students of Brigham Young University, and by grants to JWS, Jr. from the BYU College of Biology and Agriculture, the Monte L. Bean Life Science Museum, and the Committee for Research and Exploration of the National Geographic Society. Funding for some specimen collection and the DNA sequencing was provided by a Mentoring Environment Grant and a John A. Widtsoe Fellowship, Brigham Young University (to DSR). Specimens collected and used in the DNA sequencing portion of this paper were collected under permit SGPA/DGVS/04103/09 issued to F. X. González Cózatl by the Dirección General de Vida Silvestre, SEMARNAT.

Publisher Copyright:
© The Author 2017. Published by Oxford University Press on behalf of American Society of Mammalogists.


  • Chiapas
  • El Pozo
  • La Pera
  • Mexico
  • Ototylomys
  • Tylomyinae
  • Tylomyini
  • big-eared climbing rat


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