Abstract from Hesperaletes (Mammalia: Perissodactyla), a new tapiroid from the Middle Eocene of southern California, by M. W. Colbert (Journal of Vertebrate Paleontology, 2006, 23:697-711):

       Two new species of tapiroid perissodactyls referred to Hesperaletes gen. nov. are described from the        Uintan of southern California. Hesperaletes has a deeply retracted narial incision, which is an        indicator of prehensile proboscis development. This feature also characterizes early Oligocene        Protapirus from North America and has been used to diagnose Tapiridae. All late Uintan samples from        San Diego County, California, are referred to H. borineyi sp. nov., but anomalous patterns of variability        and morphological variation prohibit referral of much smaller early Uintan samples to a single species.        Most of the early Uintan samples are referred to H. walshi sp. nov. with the exception of one sample,        which is referred to cf. Hesperaletes. North American Protapirus and Hesperaletes show many cranial        similarities, and phylogenetic analysis resolves them as members of an unnamed clade, implying that        Hesperaletes is a tapirid.

This specimen, the holotype, was collected from the late Uintan Member "C," Santiago Formation, College Boulevard Locality (SDSNH loc. 3378), San Diego County, California. It was made available for scanning by Dr. Matthew Colbert of The University of Texas at Austin.

The specimen was scanned by Matthew Colbert on 10 April 2004 along the coronal axis for a total of 919 slices. Each 1024x1024 pixel slice is 0.1626 mm thick, with an interslice spacing of 0.1626 mm and a field of reconstruction of 74 mm.

Literature

Cerdeño, E., and L. Ginsburg. 1988. Les Tapiridae (Perissodactyla, Mammalia) de l'Oligocène et du Miocène inférieur Européens. Annales de Paléontologie 74:71–96.

Cifelli, R. L. 1982. The petrosal of Hyopsodus with respect to that of some other ungulates, and its phylogenetic implications. Journal of Palaeontology 56:795–805.

Colbert, M. W. 1991. A reassessment of tapiroid phylogeny: implications of a new species of Eocene “tapir” from San Diego County, California. Journal of Vertebrate Paleontology 11(3, Supplement):23A.

Colbert, M. W. 1993. New species of tapiroids from the Eocene of San Diego County, California, and their implications to tapiroid phylogeny and evolution. M.S. thesis, San Diego State University, San Diego, California, 271 pp.

Colbert, M. W. 1999. Patterns of evolution and variation in the Tapiroidea (Mammalia: Perissodactyla). Ph.D. dissertation, The University of Texas at Austin, Austin, Texas, 464 pp.

Colbert, M. W. 2005. The facial skeleton of the early Oligocene Colodon (Perissodactyla, Tapiroidea). Palaeontologia Electronica 8:27 pp., 600 kB; http://palaeo-electronica.org/paleo/2005_1/colbert12/issue1_05.htm.

Colbert, M. W. 2006. Variation and species recognition in Eocene tapirs from southern California. Journal of Vertebrate Paleontology in press.

Colbert, M. W., and R. M. Schoch. 1998. Tapiroidea and other moropomorphs; pp. 569–582 in C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary Mammals of North America. Cambridge University Press, Cambridge, United Kingdom.

Flynn, J. J. 1986. Correlation and geochronology of middle Eocene strata from the western United States. Palaeogeography, Palaeoclimatology, Palaeoecology 55:335-406.

Golz, D. J. 1976. Eocene Artiodactyla of southern California. Los Angeles Natural History Museum Bulletin 26:1–85.

Golz, D. J., and J. A. Lillegraven. 1977. Summary of known occurrences of terrestrial vertebrates from Eocene strata of southern California. University of Wyoming Contributions to Geology 15:43–65.

Gregory, W. K. 1920. Studies of comparative myology and osteology, no.V: On the anatomy of the preorbital fossae of Equidae and other ungulates. Bulletin of the American Museum of Natural History 42:265–283.

Hanson, C. B. 1996. Stratigraphy and vertebrate faunas of the Bridgerian-Duchesnean Clarno Formation, north-central Oregon; pp. 206–239 in D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America. Cambridge University Press, New York.

Holbrook, L. T. 1999. The phylogeny and classification of tapiromorph perissodactyls (Mammalia). Cladistics 15:331–350.

Hooker, J. J. 1989. Character polarities in early perissodactyls and their significance for Hyracotherium and infraordinal relationships; pp. 79–101 in D. R. Prothero and R. M. Schoch (eds.), The Evolution of the Perissodactyls. Oxford University Press, New York.

Hough, J. 1955. An Upper Eocene fauna from the Sage Creek area, Beaverhead County, Montana. Journal of Palaeontology 29:22–36.

Kelly, T. S. 1990. Biostratigraphy of Uintan and Duchesnean land mammal assemblages from the middle member of the Sespe Formation, Simi Valley, California. Contributions in Science, Natural History Museum of Los Angeles County 419:1–42.

Lillegraven, J. A. 1979. A biogeographical problem involving comparison of later Eocene terrestrial faunas of western North America; pp. 333–347 in J. Gray and A. J. Boucot (eds.), Historical Biogeography, Plate Tectonics, and the Changing Environment. Oregon State University Press, Corvallis.

Lucas, S. G., S. E. Foss, and M. C. Mihlbachler. 2004. Acaenodon (Mammalia, Artiodactyla) from the Eocene Clarno Formation, Oregon, and the age of the Hancock Quarry local fauna. New Mexico Museum of Natural History and Science Bulletin 26:89–95.

MacFadden, B. J. 1980. Eocene perissodactyls from the type section of the Tepee Trail Formation of northwestern Wyoming. Contributions to Geology, University of Wyoming 18:135–143.

McCarroll, S. M., J. J. Flynn, and W. D. Turnbull. 1996a. Biostratigraphy and magnetostratigraphy of the Bridgerian-Uintan Washakie Formation, Washakie Basin, Wyoming; pp. 25–39 in D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America. Cambridge University Press, New York.

McCarroll, S. M., J. J. Flynn, and W. D. Turnbull. 1996b. The mammalian faunas of the Washakie Formation, Eocene age, of southern Wyoming. Part III. The perissodactyls. Fieldiana, Geology, n.s. 33:1–37.

Novacek, M. J., and J. A. Lillegraven. 1979. Terrestrial vertebrates from the later Eocene of San Diego County, California; pp. 69–79 in P. L. Abbott (ed.), Eocene Depositional Systems, San Diego, California. Society of Economic Paleontologists and Mineralogists, Pacific Section, Field Trip Guidebook.

Owen, R. 1848. Description of teeth and portions of jaws of two extinct anthracotherioid quadrupeds (Hyopotamus vectianus and Hyop. bovinus) discovered by the Marchioness of Hastings in the Eocene deposits on the N. W. coast of the Isle of Wight: with an attempt to develop Cuvier’s idea of the classification of pachyderms by the number of their toes. Quarterly Journal of the Geological Society of London 4:103–141.

Radinsky, L. B. 1963. Origin and early evolution of North American Tapiroidea. Bulletin of the Peabody Museum of Natural History 17:1–115.

Radinsky, L. B. 1965a. Early Tertiary Tapiroidea of Asia. Bulletin of the American Museum of Natural History 129:183–263.

Radinsky, L. B. 1965b. Evolution of the tapiroid skeleton from Heptodon to Tapirus. Bulletin of the Museum of Comparative Zoology 134:69–103.

Reshetov, V. Y. 1979. [Early Tertiary Tapiroidea of Mongolia and the USSR]. Sovmestnaya Sovestsko-Mongoloskaya Paleontologicheskaya Ekspeditsiya Trudy 11:1–144. [Russian]

Rowe, T. 1986. Osteological diagnosis of Mammalia, L. 1758, and its relationship to extinct Synapsida. Ph.D. dissertation, University of California, Berkeley, California, 446 pp.

Schiebout, J. A. 1977. Eocene Perissodactyla from the La Jolla and Poway groups, San Diego County, California. Transactions of the San Diego Society of Natural History 18:217–228.

Schoch, R. M. 1989. A review of the tapiroids; pp. 298–320 in D. R. Prothero and R. M. Schoch (eds.), The Evolution of the Perissodactyls. Oxford University Press, New York.

Scott, W. B. 1941. The mammalian fauna of the White River Oligocene. Part V. Perissodactyla. Transactions of the American Philosophical Society 28:747–775.

Solounias, N. 2001. Probable function of the preorbital fossa of extinct horses (Equidae, Mammalia). Journal of Morphology 248:286–287.

Solounias, N, and M. W. Colbert. 2001. Reconstruction of the narial cavity of Merychippus insignis and comparisons with the modern horse, Equus caballus. Journal of Vertebrate Paleontology, 21(3, Supplement):103A.

Stock, C. 1936. Perissodactyla of the Sespe Eocene, California. Proceedings of the National Academy of Sciences, U.S.A. 22:260–265.

Wall, W. P. 1980. Cranial evidence for a proboscis in Cadurcodon and a review of snout structure in the family Amynodontidae (Perissodactyla, Rhinocerotoidea). Journal of Palaeontology 54:698–977.

Walsh, S. L. 1991. Eocene mammal faunas of San Diego County; pp. 161–178 in P. L. Abbott and J. A. May (eds.), Eocene Geologic History San Diego Region. Society of Economic Paleontologists and Mineralogists, Pacific Section, v. 68.

Walsh, S. L. 1996. Middle Eocene mammalian faunas of San Diego County, California; pp. 75–119 in D. R. Prothero and R. M. Schoch (eds.), The Evolution of the Perissodactyls. Oxford University Press, New York.

Witmer, L. M., S. D. Sampson, and N. Solounias. 1999. The proboscis of tapirs (Mammalia: Perissodactyla): a case study in novel narial anatomy. Journal of Zoology 249:249–267.

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