Bulletin 73

New Mexico Museum of Natural History & Science

A Division of the DEPARTMENT OF CULTURAL AFFAIRS

THE RED CORRAL (PROCTOR RANCH) LOCAL FAUNA (PLIOCENE, BLANCAN) OF OLDHAM COUNTY, TEXAS

by GERALD E. SCHULTZ

Albuquerque, 2016 Bulletin 73

New Mexico Museum of Natural History & Science

A Division of the DEPARTMENT OF CULTURAL AFFAIRS

THE RED CORRAL (PROCTOR RANCH) LOCAL FAUNA (PLIOCENE, BLANCAN) OF OLDHAM COUNTY, TEXAS

GERALD E. SCHULTZ

New Mexico Museum of Natural History & Science Albuquerque, 2016 STATE OF NEW MEXICO Department of Cultural Affairs Veronica Gonzales, Secretary

NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCE Margaret Marino, Executive Director

BOARD OF TRUSTEES Susanna Martinez, Governor, State of New Mexico, ex officio Margaret Marino, Executive Director, ex officio Gary Friedman, President Leonard Duda Maya Elrick, Ph.D. Peter F. Gerity, Ph.D. Deron Knoner Laurence Lattman, Ph.D. Viola Martinez Mike Mertz Marvin Moss John Montgomery, Ph.D. Jennifer Riordan Laura Smigielski-Garcia Steve West

Cover illustration: Right dentary of Miracinonyx studeri (see Figure 30)

Original Printing ISSN: 1524-4156

Available from the New Mexico Museum of Natural History and Science, 1801 Mountain Road NW, Albuquerque, NM 87104; Telephone (505) 841-2800; Fax (505) 841-2866; www.nmnaturalhistory.org

NMMNH Bulletins online at: http://nmnaturalhistory.org/bulletins BULLETIN OF THE NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCE

EDITORS

Spencer G. Lucas New Mexico Museum of Natural History and Science, Albuquerque, NM, USA (NMMNHS) Robert Sullivan NMMNHS Lawrence H. Tanner Le Moyne College, Syracuse, NY, USA

MANAGING EDITOR

Asher J. Lichtig NMMNHS

ASSOCIATE EDITORS

Guillermo Alvarado Asociación Costarricense de Geotecnica, San José, Costa Rica Marco Avanzini Museo Tridentino di Scienze Naturali, Trento, Italy David Berman Carnegie Museum of Natural History, Pittsburgh, PA, USA Brent Breithaupt Laramie, WY, USA William DiMichele National Museum of Natural History, Washington, D.C., USA John R. Foster Museum of Western Colorado, Grand Junction, CO, USA Gerard Gierlinski Polish Geological Institute, Warsaw, Poland Jean Guex University of Lausanne, Lausanne, Switzerland Jerald D. Harris Dixie State College, St. George, UT, USA Andrew B. Heckert Appalachian State University, Boone, NC, USA Adrian P. Hunt Flying Heritage Collection, Everett, WA, USA Hendrik Klein Neumarkt, Germany Karl Krainer University of Innsbruck, Innsbruck, Austria Martin G. Lockley University of Colorado at Denver, Denver, CO, USA Claudia Marsicano Universidad de Buenos Aires, Buenos Aires, Argentina Gary S. Morgan NMMNHS Donald R. Prothero Occidental College, Los Angeles, CA, USA Silvio Renesto Università degli Studi dell’Insubria, Varese, Italy Joerg W. Schneider Technical University BergAkademie of Freiberg, Freiberg, Germany Jingeng Sha Nanjing Institute of Geology and Palaeontology, Nanjing, China Sebastian Voigt Urweltmuseum GEOSKOP/Burg Lichtenburg, Thallichtenberg, Germany Ralf Werneburg Naturhistorisches Museum Schloss Bertholdsburg, Schleusingen, Germany Richard S. White, Jr. International Wildlife Museum, Tucson, AZ, USA NEW MEXICO MUSEUM OF NATURAL HISTORY AND SCIENCE BULLETINS

37. The Triassic-Jurassic Terrestrial Transition, 2006. edited by Jerry D. Harris, Spencer G. Lucas, Justin A. Spielmann, Martin G. Lockley, Andrew R.C. Milner and James I. Kirkland, 607 pp. 38. Pennsylvanian-Permian Fusulinaceans of the Big Hatchet Mountains, New Mexico, 2006. by Garner L. Wilde, 331 pp. 39. Upper Aptian-Albian Bivalves of Texas and Sonora: Biostratigraphic, Paleoecologic and Biogeographic Implications, 2007. edited by Robert W. Scott, 39 pp. 40. Triassic of the American West, 2007. edited by Spencer G. Lucas and Justin A. Spielmann, 247 pp. 41. The Global Triassic, 2007. edited by Spencer G. Lucas and Justin A. Spielmann, 415 pp. 42. Cenozoic Vertebrate Tracks and Traces, 2007. edited by Spencer G. Lucas, Justin A. Spielmann and Martin G. Lockley, 330 pp. 43. The Late Triassic archosauromorph Trilophosaurus, 2008. by Justin A. Spielmann, Spencer G. Lucas, Larry F. Rinehart and Andrew B. Heckert, 177 pp. 44. Neogene Mammals, 2008. edited by Spencer G. Lucas, Gary S. Morgan, Justin A. Spielmann and Donald R. Prothero, 442 pp. 45. The Paleobiology of Coelophysis bauri (Cope) from the Upper Triassic (Apachean) Whitaker quarry, New Mexico, with detailed analysis of a single quarry block, 2009. by Larry F. Rinehart, Spencer G. Lucas, Andrew B. Heckert, Justin A. Spielmann and Matthew D. Celeskey, 260 pp. 46. The taxonomy and paleobiology of the Late Triassic (Carnian-Norian: Adamanian-Apachean) drepanosaurs (Diapsida: Archosauromorpha: Drepanosauromorpha, 2010. by Silvio Renesto, Justin A. Spielmann, Spencer G. Lucas and Giorgio Tarditi Spagnoli, 81 pp. 47. Ichnology of the Upper Triassic (Apachean) Redonda Formation, east-central New Mexico, 2010. by Spencer G. Lucas, Justin A. Spielmann, Hendrik Klein and Allan J Lerner, 75 pp. 48. New Smithian (Early Triassic) ammonoids from Crittenden Springs, Elko County, Nevada: Implications for taxonomy, biostratigraphy and biogeography, 2010. by James F. Jenks, Arnaud Brayard, Thomas Brühwiler and Hugo Bucher, 41 pp. 49. Carboniferous-Permian transition in Cañon del Cobre, northern New Mexico, 2010. edited by Spencer G. Lucas, Jörg W. Schneider and Justin A. Spielmann, 229 pp. 50. Review of the tetrapod ichnofauna of the Moenkopi Formation/Group (Early-Middle Triassic) of the American Southwest, 2010. by Hendrik Klein and Spencer G. Lucas, 67 pp. 51. Crocodyle tracks and traces, 2010. edited by Jesper Milàn, Spencer G. Lucas, Martin G. Lockley and Justin A. Spielmann, 244 pp. 52. Selachians from the Upper Cretaceous (Santonian) Hosta Tongue of the Point Lookout Sandstone, central New Mexico, 2011. by Jim Bourdon, Keith Wright, Spencer G. Lucas, Justin A. Spielmann and Randy Pence, 54 pp. 53. Fossil Record 3, 2011. edited by Robert M. Sullivan, Spencer G. Lucas and Justin A. Spielmann, 736 pp. 54. Ichnology of the Mississippian Mauch Chunk Formation, eastern Pennsylvania, 2012. by David L. Fillmore, Spencer G. Lucas and Edward L. Simpson, 136 pp. 55. Tetrapod fauna of the Upper Triassic Redonda Formation, east-central New Mexico: The characteristic assemblage of the Apachean land-vertebrate faunachron, 2012. by Justin A. Spielmann and Spencer G. Lucas, 119 pp. 56. Revision of the Lower Triassic tetrapod ichnofauna from Wióry, Holy Cross Mountains, Poland, 2012. by Hendrik Klein and Grzegorz Niedzwiedzki, 62 pp. 57. Vertebrate Coprolites, 2012. edited by Adrian P. Hunt, Jesper Milàn, Spencer G. Lucas and Justin A. Spielmann, 387 pp. 58. A new archaic basking shark (Lamniformes: Cetorhinidae) from the late Eocene of western Oregon, U.S.A., and description of the dentition, gill rakers and vertebrae of the recent basking shark Cetorhinus maximus (Gunnerus), 2013. by Bruce J. Welton, 48 pp. 59. The Carboniferous-Permian transition in central New Mexico, 2013. edited by Spencer G. Lucas, W. John Nelson, William A. DiMichele, Justin A. Spielmann, Karl Krainer, James E. Barrick, Scott Elrick and Sebastian Voigt, 389 pp. 60. The Carboniferous-Permian transition, 2013. edited by Spencer G. Lucas, William A. DiMichele, James E. Barrick, Joerg W. Schneider and Justin A. Spielmann, 465 pp. 61. The Triassic System: New Developments in Stratigraphy and Paleontology, 2013. edited by Lawrence H. Tanner, Justin A. Spielmann and Spencer G. Lucas, 612 pp. 62. Fossil Footprints of Western North America, 2014. edited by Martin G. Lockey and Spencer G. Lucas, 508 pp. 63. Variation in the Dentition of Coelophysis bauri, 2014. by Lisa G. Buckley and Philip J. Currie, 73 pp. 64. Conodonts from the Carnian-Norian Boundary (Upper Triassic) of Black Bear Ridge, Northeastern British Columbia, Canada, 2014, by Michael J. Orchard, 139 pp. 65. Carboniferous-Permian Transition in the Robledo Mountains Southern New Mexico, 2015, edited by Spencer G. Lucas and William A. DiMichele, 167 pp. 66. The Marine Fish Fauna of the Middle Pleistocene Port Orford Formation and Elk River Beds, Cape Blanco, Oregon, 2015, by Bruce J. Welton, 45 pp. 67. Fossil Record 4, 2015. edited by Robert M. Sullivan and Spencer G. Lucas, 332 pp. 68. Fossil Vertebrates in New Mexico, 2015, edited by Spencer G. Lucas and Robert M. Sullivan, 438 pp. 69. The Pennsylvanian System in the Mud Springs Mountains, Sierra County, New Mexico, USA, 2016, by Spencer G. Lucas, Karl Krainer, James E. Barrick and Daniel Vachard, 58 pp. 70. Eocyclotosaurus appetolatus, a Middle Triassic Amphibian, 2016, by Rinehart and Lucas, 118 pp. 71. Cretaceous Period: Biotic Diversity and Biogeography, 2016, edited byAshu Khosla and Spencer G. Lucas, 330 pp. 72. Rotten Hill: a Late Triassic Bonebed in the Texas Panhandle, USA, 2016, by S.G. Lucas, L.F. Rinehart, A.B. Heckert, A.P. Hunt and J.A. Spielmann, 97 pp. Gerald E. Schultz, 2016, The Red Corral (Proctor Ranch) Local Fauna (Pliocene, Blancan) of Oldham County, Texas. New Mexico Museum of Natural History and Science Bulletin 73. 1 THE RED CORRAL (PROCTOR RANCH) LOCAL FAUNA (PLIOCENE, BLANCAN) OF OLDHAM COUNTY, TEXAS

GERALD E. SCHULTZ Department of Life, Earth, and Environmental Science, WT Box 60808. West Texas A&M University, Canyon, Texas 79016. Email: gschultz@wtamu. edu

Abstract—The Red Corral (Proctor Ranch) Local Fauna (LF) is a large and diverse assemblage of Pliocene (late Blancan) vertebrates and freshwater mollusks from Oldham County in the northwest part of the Texas Panhandle in the Rita Blanca Formation. To date the fauna is poorly known and little has been published. Large mammals were collected from fluvial and pond or marsh deposits on the Foy Proctor Ranch in 1952 by the Frick Laboratory in New York City and many of these are described for the first time in this study. Freshwater mollusks were collected and described in 1960 by Dwight Taylor of the U. S. Geological Survey, who coined the name Red Corral Local Fauna. During the summers of 1966-1969, about 40 tons of matrix were screen washed from two quarry sites by the author and field parties from West Texas A&M University to yield a large microvertebrate fauna including as yet unstudied remains of small fish, frogs, toads, salamanders, turtles, snakes, lizards and water or marsh birds. Over 45 species of mammals were obtained and are reported here. Soricomorphs include a medium-sized shrew, Sorex taylori, represented by over 50 dentaries (minimum of 27 individuals), and the mole Scalopus (Hesperoscalops) rexroadi. A fragmentary bat dentary (cf. Molossidae) was found. Lagomorphs include Hypolagus (3 species), Pewelagus, and Sylvilagus, initially studied and reported by the late John A. White, and the first North American record of Pliopentalagus. Rodents include Procastoroides sweeti, Spermophilus (sensu lato), Geomys, Prodipodomys, Perognathus, Peromyscus, Reithrodontomys, Onychomys, Bensonomys, Sigmodon, and Neotoma. Sigmodon minor /medius is the most abundant rodent, being represented by nearly 100 dentaries (minimum of 46 individuals) and several hundred isolated teeth. The Neotoma teeth are smaller than those from the Rexroad Locality 3 LF in Kansas and more nearly match in size those of Neotoma fossilis from Arizona. No arvicolid rodents were found. A concentration of fragmentary geomyid, heteromyid, cricetid, and leporid dentitions at one site suggests that owls may have hunted these upland forms and concentrated their skeletal remains in such a way that they were abundantly preserved in a low energy fluvial environment although no actual fossil owl pellets were found. Carnivoranes include Canis lepophagus, Urocyon, Borophagus diversidens, Taxidea, Trigonictis cookii, Bassariscus, Homotherium, and a large cat, Miracinonyx studeri, represented by skull fragments, dentitions, and associated postcranial elements. Other taxa include Megalonyx, Stegomastodon mirificus, Nannippus peninsulatus, Equus, Platygonus, Camelops, Hemiauchenia, Capromeryx,and a cervid. Of unique interest is one of the northernmost Blancan occurrences of the ground sloth, Paramylodon cf. garbanii, an immigrant from South America during the second phase of the Great American Biotic Interchange (GABI), which began about 3 Ma ago. No glyptodonts were found, however. Radiometrically datable ash beds are absent. Paleomagnetic signatures of the fossil-bearing layers at two quarry sites are weak, but several normal polarity samples suggest assignment to the Gauss chron between 3. 20-2. 58 Ma. Biocorrelation of the Red Corral LF with other North American faunas indicates assignment to the late Blancan NALMA (contra early Blancan in Janis et al., 1998, p. 637, SP1G; Janis et al., 2008, p. 713, SP1G). There are many similarities between the Red Corral LF and other Blancan faunas in southwest Kansas and Nebraska as well as in Arizona and New Mexico. The immediate habitat at the sites appears to have been a fluvial or lacustrine system bounded by a prairie mosaic.

INTRODUCTION Laboratory in New York City collected vertebrate fossils from several Blancan age faunas have been known from the Texas Panhandle localities along Rita Blanca Creek and its tributaries about 11 km (7 for over a century (Fig. 1). Fossil vertebrates from the region around miles) west and northwest of Channing in Hartley County (Fig. 2) and Mt. Blanco in Crosby County, Texas, were described by Cope (1893). also from several localities on the Foy Proctor Ranch on the west side Since then, many institutions have collected there, and an extensive of the valley of Punta de Agua Creek (below its junction with Rita literature has developed on the Blanco LF, with the most significant Blanca Creek) in northern Oldham County, about 16 km (10 miles) collections being reported by Meade (1945) and Dalquest (1975). southwest of Channing (Figs. 2-3). Only a few of these fossils have Wood et al. (1941) designated the Blanco LF as the type faunal locality been described, including a sloth (Hirschfeld and Webb, 1968), a bone- of the Blancan Provincial Age, which later became designated a North eating dog (Wang et al., 1999), and a coyote (Tedford et al., 2009). In American land mammal “age” (Evernden et al., 1964). the summer of 1954, D. E. Savage and a field party from the University In 1936, Blancan vertebrates were discovered in North Cita of California Museum of Paleontology (UCMP) in Berkeley visited Canyon, Randall County, Texas, about 22. 4 km (14 miles) southeast of the Proctor Ranch quarries, collected scraps of mammalian fossils, and Amarillo. The Cita Canyon LF (Johnston and Savage, 1955) is a large observed the presence of mollusks at one site (Proctor Pit D). Later in and diverse fauna collected initially by the Panhandle-Plains Historical the same year, C. W. Hibbard from the University of Michigan in Ann Museum in Canyon, Texas, using digging crews hired through the Arbor went to the site to collect the mollusks. D. W. Taylor collected Works Progress Administration (WPA) in the 1930s. An extensive additional mollusks from Pit D in the summer of 1957 (Loc. T 57-34 literature has developed dealing mostly with particular taxonomic and U. S. G. S. Cenozoic Locality 21040). Paleoecological analyses members of the fauna (e. g. Johnston, 1938; Stirton and Christian, of the mollusks were published by Herrington and Taylor (1958) and 1940, 1941; Savage, 1955, 1960; Mawby, 1965; Hirschfeld and Webb, Taylor (1960), who noted a similarity to the molluscan fauna from the 1968; Gillette and Ray, 1981; Wang et al., 1999; Tedford et al., 2009). Rexroad LF sites in Meade County, Kansas, 235 km (146 miles) to Many taxa remain unreported or undescribed, and a general review of the northeast. During the course of wet-screening for the mollusks, a the fauna is underway (Schultz, in prep. ). few isolated teeth of small rodents and rabbits were also discovered Evans and Meade (1945) mentioned the presence of Blancan and are now housed in the collections of the University of Michigan mammals in what they named the Rita Blanca beds from localities Museum of Paleontology (UMMP). The name Red Corral LF was west and northwest of Channing, Hartley County, Texas, and Norton coined by Taylor (1960) for the mammals and mollusks known from (1954) reported a small Blancan fauna from near Hereford (Hereford these localities because of a prominent red painted cattle pen located 1. Dump LF) in Deaf Smith County, Texas. Both faunas were cited by 6 km (1 mile) south of the quarries. The present study was begun in an Johnston and Savage (1955). Finally, although it is technically south attempt to obtain a significant microvertebrate fauna from Pit D and to of the Panhandle, the Beck Ranch LF (early Blancan) was described recover additional remains of large mammals from some of the other by Dalquest (1978) from a site near Snyder in Scurry County, Texas. quarries or pits. During the summers of 1966, 1967, 1968, and 1969, a In 1951, 1952, and 1953, N. Z. Ward and a party from the Frick total of 40 tons of matrix were collected and screen washed from Pits 2

FIGURE 2. Map of Channing, Texas area showing locations of Channing Rita Blanca/Sand Creek sites (Ch) and Red Corral (Proctor Ranch) sites (RC). FIGURE 1. Partial outline map of the Texas Panhandle showing location of Blancan faunal sites. Abbreviations: Ch = Channing localities; RC = Red Corral (Proctor Ranch); CC = Cita Canyon; H = Hereford Dump; mapping and correlation of units over any great distance is extremely B = Blanco. difficult. The best exposures are seen in small cuestas capped by white lacustrine clays and caliches, which collectively show a regional dip C and D by a party of students from West Texas State University (now to the SSW toward the Canadian River as a result of basement faulting West Texas A&M University; WT) in Canyon using the wet-screening and/or subsurface dissolution and surface collapse (Schmude, 1993). methods developed by Hibbard (1949). The results are reported here. On the Proctor Ranch, the fossil-bearing sites lie in a sequence of interbedded fluviatile and lacustrine or pond and marsh deposits GEOLOGICAL SETTING exposed on hill slopes or along small tributaries draining NE toward The fossiliferous sediments from which the Red Corral LF was Punta de Agua Creek below its junction with Rita Blanca Creek (Fig. 3). collected are considered to be a part of the Rita Blanca Formation of Fossil quarry sites are 100 to 300 meters apart and correlation between Late Cenozoic age. These beds, which were named and described by them is facilitated by thin beds of intercalated caliche. Pits B and C Evans and Meade (1945), comprise a sequence of basin-fill deposits are at approximately the same stratigraphic level (Fig. 4). A prominent, exposed primarily in denuded areas bordering intermittent tributaries gently dipping caliche unit (Caliche B) above these pits can be traced on the northeast side of the valley of Rita Blanca Creek, about 11 km around a hillside where it disappears beneath the floor of Pit D (Fig. (7 miles) WNW of Channing in SE Hartley County, Texas, and 1. 6 5). Despite the separation by Caliche B, the time differential between to 3. 2 km (1 to 2 miles) north of Farm-to-Market Road 767, which Pits B and C beneath the caliche and Pit D above the caliche is not runs from Channing to Romero (Johnston and Savage, 1955). The pronounced, as indicated by the similarity of rodent species from Pits C lower part of this sequence consists of laminated gray, lacustrine and D (Table 1). Consequently, for the purposes of biochronology and clays and interbedded sandy lenses containing fossil leaves, insects, palaeoecological reconstruction, the mammalian assemblages from Pits and small fish (Anderson and Kirkland, 1969). Less than 1. 6 km (1 A, B, C, and D as well as WT Locality 5 were combined and treated as mile) to the north, the sequence consists of reddish sands and greenish a homogeneous community, the Red Corral LF. silty clays containing late Hemphillian camel bones and white, flaggy, In general, the fossil-bearing sediments are aligned along the penecontemporaneously deformed beds of lacustrine, sandy limestone north limb of a monocline with a roughly east-west axis that lies in bearing camel track fillings on their undersides. Higher in the section the valley south of the fossiliferous strike ridge, which can be traced are calcareous sandstones, yellow sands, mudstones, and bentonitic or eastward for about 0. 8 km (0. 5 mile) before being eroded by the broad lignitic clays which have yielded fossil horses, camels, mastodons, and valley of Punta de Agua Creek. Dips of up to 10 degrees to the south other mammals of Blancan age. Near the top of the sequence on the or southwest can be observed in places along the strike ridge (Figs. 6, divide between Rita Blanca Creek on the west and its main tributary, 10). To the west, the fossiliferous units pass beneath the upland surface. Sand Creek, on the east is a deposit of Cerro Toledo X volcanic ash Buff colored silty sands to the north may represent older sediments derived from New Mexico and dated at 1. 2-1. 5 Ma (Izett et al., within the Rita Blanca Formation or possibly the Ogallala Formation 1981). Remains of mammoth have also been recovered from high in into which the Rita Blanca basin was excavated. the section, indicating a Pleistocene age for the upper-most sediments NOMENCLATURE AND DESCRIPTION OF FOSSIL in the sequence. According to information provided by the United LOCALITIES States Geological Survey, the Rita Blanca Formation makes up about two per cent of the area in Hartley County. As mentioned above, the All fossil sites are located on the Torrey House, 7 ½ minute Frick Laboratory made extensive collections from several quarries in quadrangle topographic map published by the U. S. Geological Survey. this area. Smaller collections have also been made by the West Texas The sites are all in Oldham County, about 0. 8 km (0. 5 mile) south of the Museum in Lubbock, the Panhandle-Plains Historical Museum in Hartley-Oldham County line. The ranch is privately owned – currently Canyon, Texas, and the University of California in Berkeley (Johnston by Mike Smith of Amarillo, Texas. Access is limited and permission and Savage, 1955). must be obtained from the owner or the foreman in residence. South of Farm-to-Market Road 767 on the former Proctor Ranch Red Corral LF sites (Blancan): and also SSE of Channing near U. S. Highway 385 in Oldham County, Texas, the Rita Blanca Formation is poorly exposed. As a result, 1) Proctor Pit A of Frick = WT Locality 4 (41OL-P4) = P107A 3

FIGURE 3. Topographic map of part of the Proctor Ranch showing Frick Laboratory Pits A, B, C, and D and WTAMU localities 5, 6 (Pleistocene), and 7 (Rentfro Pit 2 of Frick). 4

FIGURE 4. Stratigraphic sections at Pit B and Pit C. Abbreviations: N = normal paleomagnetic polarity sample taken next to fossil bone at Pit C. of the Panhandle-Plains Historical Museum (Fig. 3). The site is in the NE 1/4 SE 1/4 SW 1/4 sec. 3, Blk. 22, CSS (Capital Syndicate matrix were collected from the upper part of the quarry, which, when Subdivision). Fossils occur in the lower part of a 3 m (10 ft) thick screen washed, yielded a microfauna containing numerous teeth and bed of greenish-gray sandstone between two white, weathered sandy jaw fragments of geomyids, heteromyids, cricetines, and leporids. limestone units. N. Z. Ward collected fossils of horse and small camel Apparently most of the surface material collected by the Panhandle- from the site. A few fossil horse remains were collected by the WT field Plains Historical Museum and by D. E. Savage and the UCMP field party at the SW end of a small ridge. No microfauna was obtained. party came from this site. Lindsay et al. (1975) obtained a normal paleomagnetic signature on a sediment sample from the fossil-bearing 2) Proctor Pit B = WT Locality 3 (41OL-P3) = P107B = Locality layer. 7 of Savage (UCMP). The site is about 215 m (705 ft) east of Pit A and about 110 m (360 ft) northeast of Pit D on the north side of a small hill 4) Proctor Pit D = WT Locality 2 (41OL-P2) = P107D = Loc. (Fig. 3). The site is in the NW 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. 6 of Savage (UCMP) = D. W. Taylor’s mollusk locality (T 57-34 and GPS coordinates are lat. 35. 61954 degrees N. and long. 102. 48405 U. S. G. S. Cenozoic Locality 21040). The site is about 215 m (705 degrees W. Ward collected fossils of horse and small camel, a sloth ft) SE of Pit A and 110 m (360 ft) SW of Pit B along the east side tooth, and mandibles of a machairodont, a coyote, and a badger from a of a small ravine that runs into a larger tributary that enters Punta de 1. 5 m (5 ft) cut at the base of a mostly covered 6 m (20 ft) sequence of Agua Creek about 1. 6 km (1 mile) to the northeast (Figs. 3, 11, 12, greenish-gray fine sand which is overlain by a thin caliche and gravel. and 13) and is in the SW 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. The WT field party did not attempt to recover a microfauna from this GPS coordinates are lat. 35. 61875 degrees N. and long. 102. 48485 site. degrees W. The fossiliferous unit consists of 1. 5 m (5 ft) of chocolate brown mudstone or siltstone grading upward to a lavender and yellow, 3) Proctor Pit C = WT Locality 1 (41OL-P1) = P107C = Loc. papery thin shale, that contains many crushed snails and appears to 5 of Savage (UCMP V-5327). The site is about 160 m (525 ft) east of have been deposited in a pond and marsh habitat. In places the papery Pit B and about 255 m (836 ft) ENE of Pit D along a hill slope on the layers are impregnated with calcium carbonate giving it a hard, white, west side of a north-draining ravine (Figs. 3, 7, 8, and 9). and is in the blocky or punky appearance. This unit is fossiliferous throughout and NE 1/4 SW 1/4 SE 1/4 sec. 3, Blk. 22, CSS. GPS coordinates are lat. produced the mollluscan fauna reported by Taylor (1960) along with 35. 61973 degrees N. and 102. 48245 degrees W. Ward collected horse, a few rodent and rabbit teeth cataloged in the UMMP collections. A small camel, stegomastodont, borophagine dog, two kinds of sloth, and few macrovertebrates including horse, small camel, borophagine dog, an antilocaprid tooth from a 4. 5 m (15 ft) unit of mainly greenish-gray beaver, peccary, antilocaprid, and the mandible of a large jaguar-sized silty sand with some alternating layers of tan to buff colored sand. The cat were collected by Ward for the Frick Laboratory. About 28 tons WT field party collected additional macrovertebrates including horse, of matrix were collected and screen washed by a WT field party to large and small camel, stegomastodont, borophagine, and the jaws and yield the fauna here reported. Lindsay et al. (1975) obtained a weak and some postcranial bones of a large jaguar-sized cat. About 12 tons of dubious normal paleomagnetic signature from a sediment sample from 5

FIGURE 5. Stratigraphic section at Pit D showing caliche B dipping beneath exposed section at Pit D. Abbreviations: N = north, S = south, ?N = weak, probably normal paleomagnetic polarity sample taken, R = reversed paleomagnetic sample taken.

FIGURE 6. View to the northeast from Pit C showing regional dip of beds to the south at about 10 degrees. Punta de Agua Creek in the distance (below junction with Rita Blanca Creek). the fossil-bearing unit. 5) WT Locality 5 (41OL-P5). New mollusk site (Fig. 3). Center, FIGURE 7. View of Pit C (at far right with white-shirted man for scale) SE 1/4 SW 1/4 sec. 3, Blk. 22, CSS about 215 m (705 ft)west of Pit D. on the west side of small arroyo. Large outcrop at left did not yield any Small mollusks are abundant in exposures of silty clay on the south fossils. side of a small NE draining ravine. Equus jaws and a large camel radius were collected north of this ravine. The site appears to be at the same stratigraphic level as Pit D. of Blancan age, the site is not considered part of the Red Corral LF. It is Other sites: located 0. 8 km (0. 5 mile) east of the Proctor pits along the top of the strike ridge containing those pits (Fig. 3). The site is in the SW 1/4 SW 1) WT Locality 6 (41OL-P6). Pleistocene vertebrate site higher 1/4 sec. 52, Blk. B5, E . L. & Ry. Co. Survey. Fossil horse teeth were in the section (Fig. 3) located in the SE 1/4 SE 1/4 SW 1/4 sec. 3, Blk. collected by Ward and by the WT field party from a small exposure 22, CSS. of greenish-gray sandstone 0. 3-0. 6 m (10-20 ft) below a thin-bedded 2) WT Locality 7 (41OL-P7). Rentfro Pit 2 of Frick. Although ostracod-bearing limestone. 6

FIGURE 8. View of Pit C (below tarp). FIGURE 11. View of Pit D on east side of small arroyo. Fossils occur in chocolate brown shale in middle of section to the right of shovel.

FIGURE 9. View of Pit C. Students sacking dirt to be screen washed.

FIGURE 12. View of Pit D. Stack of matrix-filled burlap sacks for scale.

FIGURE 10. View to the northeast from Pit D showing regional dip of beds to the south at about 10 degrees. FIGURE 13. View to the south along face of Pit D at left. Man standing METHODS, MATERIALS, AND ABBREVIATIONS on top of dirt pile to the right of the trench for scale. Most of the specimens in the fauna were collected by the author and field parties and are housed in the collections of the Department of institutional acronym (abbreviated WT for WTAMU). Specimens Life, Earth, and Environmental Science, West Texas A&M University from other institutions either described herein or referred to in the in Canyon. Only the mammals have been assigned catalog numbers. text and/or tables for comparison bear the following acronyms: ANSP In the following fossil descriptions, specimen numbers without an (Academy of Natural Sciences Philadelphia); F:AM (Frick: American acronym are from WTAMU (formerly West Texas State University). Museum Mammals collection in the American Museum of Natural Some earlier references may use the prefix WTSU, and some of History); IGM (Instituto de Geologia, Mexico); KU (University of the tables included here may use the prefix WT. When a specimen Kansas in Lawrence); UCMP (University of California Museum of number appears at the beginning of a sentence, it is preceded by the Paleontology in Berkeley); UMMP (University of Michigan Museum 7 of Paleontology in Ann Arbor); USNM (United States National TABLE 1. Mammalian Faunal List (X = Presence of taxon at site) Museum, Washington DC). All measurements are in millimeters unless Pit A Pit B Pit C Pit D Loc. 5 otherwise indicated. Small specimens were measured to the nearest 0. Class Mammalia 05 mm using a calibrated ocular scale in a Bausch and Lomb binocular Order Soricomorpha microscope. Large specimens were measured to the nearest 0. 05 mm Family Soricidae using a standard dial calipers or, in a few cases, a metric bar scale for Sorex taylori Hibbard, 1938 X X long bones. Abbreviations used throughout the text and in the tables Family Talpidae include AP = anteroposterior; L = length; LF = local fauna; N = sample Scalopus (Hesperoscalops) rexroadi (Hibbard, 1941b, c) X X size; OR = observed range; SD = standard deviation; TW = transverse Order Chiroptera width; W = width. Other abbreviations and measurements are explained Family cf. Molossidae X in the text or table captions. Order Xenarthra SYSTEMATIC PALEONTOLOGY Family Megalonychidae Megalonyx sp. X Class Osteichthyes – tentative identification of ictalurid (catfish) Family Mylodontidae bones was made by Gerald Smith of the UMMP. Paramylodon cf. garbanii Montellano & Carranza, 1986 X X Class Amphibia – preliminary identifications were made by Order Lagomorpha the late J. Alan Holman of Michigan State University (personal Family Leporidae communication). Urodeles include two kinds of Ambystoma. Anurans Hypolagus furlongi Gazin, 1934a X X include Scaphiopus (based on a sacrococcyx), Acris (ilium), Hyla Hypolagus edensis Frick, 1921 X X (ilium), Rana (numerous ilia), and Bufo cf. woodhousei. Most of the Hypolagus gidleyi White, 1987 X fossils were obtained from Pit D. Pewelagus dawsonae White, 1984 X Sylvilagus hibbardi White, 1984 X X Class Reptilia – preliminary identifications were made by the Pliopentalagus sp. X late J. Alan Holman. Chelonians, based on fragments of carapace Order Rodentia or plastron, include Geochelone (now Hesperotestudo) large sp., Family Sciuridae H. turgida, Pseudemys (now Trachemys), a small emydid (possibly Marmotini genus and species indet. - large X X Chrysemys), Terrapene, Kinosternon, Chelydra, and possibly Trionyx Marmotini genus and species indet. - medium X X (now Apalone). Lizards include Phrynosoma (horns), a sceloporine, Marmotini genus and species indet. - small X Cnemidophorus (now Aspidoscelis), and Eumeces (now relegated to Family Castoridae several genera; two species). Snakes, identified primarily on vertebrae, Procastoroides sweeti Barbour and Schultz, 1937 X include a crotalid (now crotaline), Pituophis, and numerous natricines Family Geomyidae including at least two species (a ribbon snake and the genus Natrix- Geomys (Nerterogeomys) cf. minor Gidley, 1922 X X now Nerodia). Most of the fossils were obtained from Pit D and a few Geomys sp. - large X X from Pit C. Numerous parts of a Kinosternon carapace were found at Family Heteromyidae Locality 5. Prodipodomys cf. idahoensis Hibbard, 1962 X X Class Aves – preliminary identifications were made by Robert Perognathus cf. gidleyi Hibbard, 1941b, c X X Weigel of Illinois State University. Pit C produced a distal end and Perognathus cf. pearlettensis Hibbard, 1941a X the lateral spur of a tarsometatarsus of a turkey, probably Meleagris, Family Cricetidae as well as a few small unidentifiable bones and egg shell fragments. Peromyscus sp. - large X X Most of the fossils were recovered from Pit D and include coracoids, Peromyscus spp. - small X X carpometacarpi, beaks and other elements of coot, rail, gallinule Reithrodontomys cf. rexroadensis Hibbard, 1952a X (swamp hen), duck, teal, ibis or heron, swan, and even owl. Numerous Onychomys cf. pedroensis Gidley, 1922 X X egg shell fragments were also found. Bensonomys cf. arizonae (Gidley, 1922) X X Sigmodon minor /medius Gidley, 1922 X X Class Mammalia – over 45 species of mammals are herein Neotoma (Paraneotoma) cf. fossilis Gidley, 1922 X X reported. A mammalian faunal list is given in Table 1. Order Carnivora Class Mammalia Family Canidae Order Soricomorpha Canis lepophagus Johnston, 1938 X X X Family Soricidae Urocyon sp. X Sorex taylori Hibbard, 1938 Borophagus diversidens Cope, 1892 X X X Figure 14A Family Mustelidae Trigonictis cookii (Gazin, 1934b) X Referred specimens. Pit C: 4300, edentulous left dentary. Pit D: Taxidea sp. X 4000-4007, 4122-4130, 27 left dentaries and dentary fragments; 4008- Family Procyonidae 4014, 4131-4136, 23 right dentaries and dentary fragments; 4015, left Bassariscus sp. X maxillary, P4-M2; 4016, left maxillary, I3-P4 and an isolated left M1. A Family Felidae minimum of 27 individuals are present in the sample from Pit D. Homotherium sp. X X Description. Hibbard (1938) named and described Sorex taylori Miracinonyx studeri (Savage, 1955) X X based on several dentaries from Rexroad Locality 2, Meade County, Felis sp. - small X X X Kansas, 235 km (146 miles) northeast of the Red Corral sites. He Order Proboscidea characterized this shrew as being the size of the Holocene Sorex Family Gomphotheriidae merriami Dobson and gave the following diagnosis: “Protoconid Stegomastodon mirificus (Leidy, 1858) X appressing metaconid in m1; m2 and m3 greater (larger) than in Order Perissodactyla living species. All five cusps are developed in the molars; accessory Family Equidae cusps wanting; cingulum strongly developed; ascending ramus well- Nannippus peninsulatus (Cope, 1885) X X X X X developed; coronoid process high and narrow leaving the horizontal Equus spp. X X X X X ramus at a right angle; m3 nearer to ascending ramus than in living Order Artiodactyla species. ”The length of m1-m3 in the holotype, KU 3906, is 3. 4. Family Tayassuidae Additional jaws were recovered from Rexroad Locality 2 and Locality Platygonus sp. X X 3 (Hibbard, 1941c, 1953a). Skinner et al. (1972) further noted that the Family Camelidae talonids of m1-m3 are about the same width as the trigonids and that, Camelops sp. X X in young adults, the apex of the crown of the first unicuspid is close to Hemiauchenia cf. blancoensis (Meade, 1945) X X X X X the anterior edge of p4. Family Antilocapridae The availability of a large sample of Sorex taylori (minimum of Capromeryx sp. X X 27 individuals from Pit D) provides an opportunity to reexamine and Family Cervidae reassess the diagnostic characteristics previously given for the species. Genus and species indet. X 8

FIGURE 14. Sorex taylori: A, left dentary with incisor, canine, and p3-m3, 4000, Pit D. cf. Molossidae: B, edentulous left dentary, 4316, Pit C. Scalopus (Hesperoscalops) rexroadi: C, right maxillary with M1-M3, 4307, Pit C; D, left M2, 4017, Pit D; E, right humerus, 4310, Pit C; F, right dentary with m1-m3, 4301, Pit C; G, left dentary with m1-m2, 4302, Pit C. S. taylori appears to be about the size of the Holocene S. merriami cingulum is present anterior to the protocone on both M1s but is absent Dobson as proposed by Hibbard (1938). In general, the dentary is light on the M2. Eshelman (1975) observed the same condition in a maxillary and rather slender – not heavy or robust (Fig. 14A). The coronoid of Sorex taylori from the Wendell Fox LF of Kansas. By contrast, in S. process is high and narrow and perpendicular to the horizontal ramus. sandersi, the anterior cingulum is much better developed on M1 and is The protoconid is closely appressed to the metaconid in m1 of young also present on M2. adult individuals that comprise most of the sample. This condition is Remarks. Several species of Sorex have been described from not apparent in the few middle to old adult individuals observed. A Blancan faunas but nearly all are known from only a few specimens. broad reentrant valley separates the paraconid and the metaconid in m1. Four species from the early Blancan Hagerman LF of Idaho (Hibbard Contrary to Skinner et al. (1972), the talonids and trigonids are not of and Bjork, 1971) are easily distinguishable from S. taylori. In S. powersi equal width in all of the molars but only in m2 (20 of 24). In m1, the there is a posterior mandibular foramen that is larger than the anterior talonid is wider than the trigonid, whereas in m3 the reverse is true. one, and both are situated in a deep depression. S. hagermanensis has An entoconid is strongly developed on m1 and m2 but is weak on m3. a heavier and larger jaw and also has a posterior mandibular foramen. However, the talonid on m3 is not significantly reduced. Cingula are S. meltoni is smaller – about the size of S. cinereus – and also has a usually present on the lower molars, but their development is variable. posterior mandibular foramen. S. rexroadensis, known also from the Fox The p4 is round and broad. An incisor is preserved in two specimens. Canyon LF of Kansas (Hibbard, 1950), is the smallest Blancan shrew. In one it is broken, but in the other it is complete and contains two A posterior mandibular foramen is present in the Fox Canyon holotype denticles on the occlusal edge. The mental foramen is small and located but not in the Idaho specimens. S. sandersi from the late Blancan below or just behind the protoconid of m1. The anterior mandibular Sanders LF (Hibbard, 1956) and White Rock LF (Eshelman, 1975) of foramen is typically small and located below the middle of the ramal Kansas and the Sand Draw LF of Nebraska (Skinner et al., 1972) lacks fossa. In two specimens it is larger and located below the front and the a posterior mandibular foramen but is slightly larger and has a heavier back, respectively, of the ramal fossa. There is no posterior mandibular jaw than S. taylori, and the p4 is less rounded and narrower. Length foramen on any of the specimens. Length of m1-m3 in Pit D sample: N = of m1-m3 in the holotype, UMMP V31976, is 3. 8. S. leahyi from the 9; OR = 3. 4-3. 7; Mean = 3. 54. Additional tooth and jaw measurements late Blancan Dixon LF of Kansas (Hibbard, 1956) is also larger than following those used by Jammot (1972) are given in Table 2. S. taylori and also lacks a posterior mandibular foramen, and the teeth Two M1s and one M2 are present in the sample; a very small are reported to be slightly narrower. The holotype, UMMP V31969, 9 TABLE 2. Measurements (in mm) of Sorex taylori dentaries from Red Corral Pit D. Measurements used follow Jammot (1972). Abbreviations: L = lower jaw measured fromthe ventral angular inflection to the mental foramen.H = height of ascending ramus measured from the ventral angular inflection to the tip of the coronoid process.m1-m3 = greatest occlusal length of lower molars. h1 = lingual jaw depth below entoconid of m1. left jaws right jaws WT No. L H m1-m3 h1 WT No. L H m1-m3 h1 4000 4.7 brk. 3.5 1.3 4008 NA NA 3. 5 1.2 4001 4.4 4 3.7 1.3 4009 4.5 4.05 NA 1.3 4002 4. 4. 1 NA 1.3 4010 NA 3.9 NA NA 4003 brk. 3. 65 3. 5 1.3 4011 4. 5 4 NA 1.3 4004 4.6 brk. NA 1.3 4012 4. 5 3.95 NA 1.2 4005 NA NA 3.5 1.3 4013 NA 3.95 NA NA 4006 NA NA 3.6 1.2 4131 4.5 3.9 NA 1.2 4122 4.2 3.9 3.6 NA 4132 NA NA NA 1.3 4123 NA 4.1 NA NA 4133 NA NA 3. 4 1.2 4124 NA NA NA 1.3 4134 4.5 NA 3. 6 1.3 4125 NA NA NA 1.15 4135 NA NA NA NA 4126 NA NA NA NA 4136 NA NA NA 1.1 4127 4.5 NA NA 1.35 4014a 4.6 3.95 NA 1.1 4128 NA NA NA NA 4014b 4.6 3.95 NA 1.2 4129 NA NA NA 1 4014c NA 4.1 NA NA 4130 NA NA NA NA 4014d NA NA NA NA 4007a 4.6 NA NA 1. 3 4007b NA 3. 75 NA NA 4007c NA 3. 8 NA NA 4007d NA 3. 8 NA NA

N 7 8 6 12 N 7 9 3 11 OR 4. 2-4. 7 3. 65-4. 1 3. 5-3. 7 1. 0-1. 35 OR 4.5-4.6 3.9-4.1 3.4-3.6 1.1-1.3 Mean 4. 5 3. 89 3. 57 1. 26 Mean 4.53 3.97 3.5 1.22 SD 0. 163 0. 166 0. 082 0. 097 SD 0. 049 0. 067 0.1 0.075

Combined sample (left and right jaws) Note: lefts and rights of single individuals may be present in 14 17 9 23 combined samples. OR 4.2-4.7 3.65-4.1 3. 4-3.7 1.0-1.35 Mean 4.51 3.93 3.54 1.24 SD 0.117 0.127 0.088 0.088 lacks m1. However, m1 is present in the paratype, UMMP V31970, and the two cusps are more closely appressed in m3 than in m1 or m2. the length of m1-m3 = 3. 6. S. leahyi is supposedly distinguished by a The protoconid, entoconid, and hypoconid are well-developed in all narrower and distinctly developed posterointernal ramal fossa and by three teeth. The anterointernal basal accessory cusp (aibac) is present a broad, flattened posterior border on the coronoid process. However, on all three teeth – widest (0. 9x0. 4) on m3 (about 2/3 the width of because of the considerable variability of some features in Sorex, the trigonid) but narrower on m1 (0. 8x0. 3) and m2 (0. 8x0. 4). It additional specimens of both S. sandersi and S. leahyi are needed to projects forward about 0. 4 and upward at its anterior edge to enclose further delineate differences and similarities between these two species a labially sloping groove. The posterointernal basal accessory cusp and S. taylori. Skinner et al. (1972) suggested that S. sandersi may have (pibac) is present on m1 (0. 4x0. 3) and m2 (0. 4x0. 3) but absent on been derived from S. taylori. m3. It is narrower than the aibac and overlaps lingually that cusp on the Sorex taylori is currently known or reported from Rexroad next molar behind. The external median basal accessory cusp (embac) Localities 2, 2a, and 3 (Hibbard, 1938, 1941c) and the Borchers LF extends forward from the anterior wall of the talonid. This cusp is very (Hibbard, 1941a) of Kansas; the Blanco (Dalquest, 1975) and Beck prominent on m3 – nearly filling the protoconid-hypoconid valley – but Ranch (Dalquest, 1978) local faunas of Texas; and the California Wash less developed on m2 and weakly developed on m1. All three teeth are LF of Arizona (Lindsay, 1984; Morgan and White, 2005). Hibbard two-rooted. Little or no cementum is present. No foramina or processes (1953a) considered the species to be a moist, lowland dweller. This is are preserved. The lingual jaw depth below m2 is 4. 1 and below m3 consistent with its abundance at Pit D and its near absence at Pit C in is 3. 6. the Red Corral LF. A left dentary fragment, 4302, contains m1-m2 and the alveoli of c, p2-p4 (Fig. 14G). The teeth are less worn than in 4301. The paraconid Family Talpidae is closer to the metaconid in m2 than in m1. The aibac is small (0. 4x0. Scalopus (Hesperoscalops) rexroadi (Hibbard, 1941b, c) 2) on m1 and very large (0. 8x0. 3) on m2. The pibac is large (0. 5x0. Figures 14C-G 4) on m1 and broken off on m2. The embac is moderately developed Referred specimens. Pit C: 4301, right dentary fragment with on m2 and very faint on m1. There is cementum in both labial and m1-m3; 4302, left dentary fragment with p3-p4 alveoli, m1-m2; 4303, lingual valleys of both teeth. The jaw is broken across the m3 alveolus. right dentary with m2, m3 alveolus; 4304, right dentary with base of There is a large mental foramen below the p3 alveolus and two small the incisor, m1 and the alveoli of p3, p4, m2, and m3; 4305, edentulous ones below the m1 talonid. The lingual jaw depth below m1 is 3. 4 and right dentary fragment with m3 alveolus; 4306, edentulous left dentary below m2 is 3. 7. fragment with alveoli for m2 and m3; 4307, right maxillary fragment A right dentary fragment, 4303, is broken across the m1 alveolus with M1-M3; 4308, left maxillary fragment with M1-M2; 4309, but contains m2 and the alveolus of m3. The m2 shows little wear, isolated teeth; 4310, right humerus; 4311-4314, four left humeri; 4315, and the paraconid does not crowd the metaconid. The aibac and pibac proximal end of right ulna and parts of four others, six complete and six are prominent and the former is only slightly wider (0. 7x0. 4) than partial radii, four partial scapulae, and 12 phalanges. Pit D: 4137, left the latter (0. 5x0. 4). The embac is moderately developed. The jaw is maxillary fragment with M1-M2; 4017, left maxillary fragment with broken across the base of the ascending ramus and across the angular M2; 4018, isolated teeth; 4019, right humerus; 4020, left humerus. process. No foramina are preserved. The lingual jaw depth below m2 is Description. The subgenus Hesperoscalops is characterized by 3. 5 and below the m3 alveolus is 3. 1. the presence of large basal accessory cusps in the lower molars. WT A right dentary, 4304, broken across the base of the ascending 4301, a right dentary fragment broken anterior to m1, contains m1- ramus contains m1 and the alveoli of p3, p4, m2, and m3. The alveolar m3 and best illustrates the cusp development in this mole (Fig. 14F). length of p3-m3 is 10. 4 and that of m1-m3 is 7. 9. The m2 is moderately The paraconid is smaller than the metaconid in all three teeth, and worn. The aibac is weak, but the pibac is a strongly developed knob 10 (0. 5x0. 3). The embac is also well-developed. There is a large mental foramen below the p3 alveolus, two smaller ones below the p4 alveolus, separates the parastyle and mesostyle 1 internally in M2, although the and two still smaller ones below m1 and the m2 alveolus respectively. styles touch labially – being separated only by a slit. Valley development The lingual jaw depth below m1 is 3. 1, below the m2 alveolus is 3. is similar between mesostyle 2 and the metastyle in both M1 and M2, 5, and below the m3 alveolus is 3. 5. Measurements of isolated lower although a small cusp blocks this valley labially in M2. Two anterior molars as well as those in jaw fragments from Red Corral Pits C and D roots are present on each tooth, but the posterior roots are fused into and Blancan sites in Kansas and elsewhere in the Texas Panhandle are one long root. The notch between the maxillary and the jugal process summarized in Table 3. ends just opposite the posterior edge of M2, as in S. (H.) rexroadi and In an edentulous right dentary fragment, 4305, the lingual jaw modern Scalopus. depth below the m3 alveolus is 3. 0 and the labial jaw depth is 2. 5. In Several other tooth-bearing maxillary fragments (Figs. 14C-D) an edentulous left dentary fragment, 4306, the lingual jaw depth below from both Pits C and D were examined. The tooth characteristics of M1 the m2 alveolus is 3. 8 and below the m3 anterior root alveolus is 3. 7. and M2 are like those in 4308. Several isolated M3s are also present in A left maxillary fragment, 4308, contains M1-M2. The the sample. M3 is smaller than the other molars and lacks a metastyle anteroposterior length of M1-M2 is 5. 4. The crowns of these teeth fit giving the tooth a rounded posterior margin. Measurements of isolated closely together along the labial side in contrast to the widely spaced upper molars as well as those in maxillary fragments are given in Table teeth in modern Scalopus. In both teeth, the protocone is a prominent 3. but low cusp which extends labially as a broad, low shelf between the Several humeri are present in the sample (Fig. 14E). They paracone and metacone. The parastyle is absent in M1, but a slight are slightly smaller than those of modern Scalopus with which they ridge along the anteroexternal root surface may represent a vestigial were compared, and the articular processes appear to be not as well- parastyle. The parastyle is well-developed in M2. A wide, deep valley developed. TABLE 3. Statistical summary of tooth measurements (in mm) of Scalopus (Hesperoscalops) from Red Corral and other Blancan local faunas. Abbreviations: L = length; Wtri = width of trigonid;Wtal = width of talonid. Red Corral Pit C Red Corral Pit D Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L +cusps 3 2. 8-3. 0 2. 9 0. 1 m1 L +cusps 1 2. 6 L -cusps 3 2. 2-2. 5 2. 37 0. 153 L -cusps 1 2. 3 Wtri 3 1. 5-1. 8 1. 63 0. 153 Wtri 1 1. 4 Wtal 3 1. 8-1. 95 1. 88 0. 076 Wtal 1 1. 8 m2 L +cusps 6 2. 8-2. 9 2. 82 0. 041 m2 L +cusps 1 2. 8 L -cusps 3 2. 1-2. 3 2. 23 0. 116 L -cusps 1 2. 1 Wtri 6 1. 7-1. 8 1. 73 0. 052 Wtri 1 1. 6 Wtal 6 1. 8-2. 0 1. 91 0. 092 Wtal 1 2 m3 L +cusps 3 2. 1-2. 3 2. 2 0. 1 L -cusps NA NA NA NA Wtri 3 1. 5-1. 6 1. 55 0. 05 Wtal 3 1. 3-1. 4 1. 33 0. 058 M1 L 8 2. 2-2. 8 2. 51 0. 164 M1 L 1 2. 5 W ant 8 2. 0-2. 3 2. 12 0. 089 W ant 1 2. 2 W post 8 1. 7-2. 2 1. 85 0. 16 W post 1 1. 8 M2 L 5 2. 3-2. 6 2. 46 0. 114 M2 L 2 2. 2-2. 5 2. 35 W ant 5 2. 1-2. 5 2. 32 0. 148 W ant 2 2. 3-2. 4 2. 35 W post 5 1. 6-1. 9 1. 76 0. 114 W post 2 1. 8-1. 9 1. 85 M3 L 5 1. 6-1. 8 1. 74 0. 089 M3 L 1 1. 9 W 5 1. 6-1. 8 1. 7 0. 071 W 1 1. 8 Rexroad Locality 3 - S. rexroadi Fox Canyon - S. rexroadi Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L +cusps 1 2. 8 m1 L +cusps 7 2. 3-2. 9 2. 63 0. 18 L -cusps 1 2. 4 L -cusps 7 2. 1-2. 4 2. 29 0. 09 Wtri 1 1. 7 Wtri 7 1. 4-1. 8 1. 54 0. 162 Wtal 1 2 Wtal 7 1. 7-2. 0 1. 82 0. 099 m2 L +cusps 2 2. 7 2. 7 m2 L +cusps 5 2. 7-3. 0 2. 82 0. 13 L -cusps 2 2. 2-2. 25 2. 22 L -cusps 5 2. 2-2. 3 2. 26 0. 055 Wtri 3 1. 7-2. 1 1. 91 Wtri 6 1. 5-1. 9 1. 73 0. 14 Wtal 3 1. 7-2. 3 2 Wtal 6 1. 7-2. 1 1. 88 0. 16 m3 L +cusps 1 2. 3 m3 L +cusps 7 2. 1-2. 5 2. 26 0. 125 L -cusps 1 2. 1 L -cusps 7 1. 9-2. 1 2. 03 0. 095 Wtri 2 1. 75-1. 9 1. 82 Wtri 7 1. 3-1. 6 1. 49 0. 122 Wtal 2 1. 3-1. 4 1. 35 Wtal 7 1. 05-1. 3 1. 18 0. 099 Rexroad Loc. 2 Type S. rexroadi Type of S. sewardensis m2 L 1 3. 2 m2 L +cusps 1 3. 55 W 1 1. 9 L -cusps 1 NA Wtri 1 2. 3 Wtal 1 2. 5

m3 L 1 2. 6 m3 L +cusps 1 2. 8 W 1 1. 6 L -cusps 1 NA Wtri 1 2. 1 Wtal 1 1. 75 11 Blanco - S. blancoensis Beck Ranch - S. rexroadi Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L +cusps 1 3. 1 m1 L +cusps 5 2. 3-2. 7 2. 47 0. 148 L -cusps 1 2. 5 L -cusps 5 2. 0-2. 3 2. 12 0. 115 Wtri 1 1. 7 Wtri 5 1. 3-1. 6 1. 42 0. 115 Wtal 1 2. 05 Wtal 5 1. 55-1. 9 1. 69 0. 134 m2 L +cusps 2 3. 1-3. 15 3. 12 m2 L +cusps 7 2. 55-2. 9 2. 68 0. 115 L -cusps 2 2. 3-2. 6 2. 45 L -cusps 7 2. 0-2. 3 2. 17 0. 111 Wtri 2 1. 6-1. 85 1. 72 Wtri 7 1. 3-1. 7 1. 46 0. 149 Wtal 2 1. 8-2. 0 1. 9 Wtal 7 1. 6-1. 9 1. 7 0. 1 m3 L +cusps 3 2. 4-2. 45 2. 42 0. 029 m3 L +cusps 5 2. 0-2. 4 2. 21 0. 143 L -cusps 3 2. 0-2. 2 2. 13 0. 116 L -cusps 5 1. 8-1. 9 1. 86 0. 055 Wtri 3 1. 45-1. 8 1. 58 0. 189 Wtri 5 1. 3-1. 5 1. 38 0. 11 Wtal 3 1. 2-1. 6 1. 43 0. 208 Wtal 5 1. 15-1. 2 1. 19 0. 022

Remarks. The genus Hesperoscalops was established because of tooth row is 65. 5 mm long. the presence of large basal accessory cusps in the lower molars (Hibbard, In anterior view the rostrum presents an elliptical narial opening 1941b, c). Kurtén and Anderson (1980) noted that similar but smaller with a maximum width of about 38 just dorsal to the palate and cusps are found in some Scalopus, however, and Hesperoscalops is narrowing to about 20 between the lateral edges of the nasal bones. The now regarded as a subgenus. Scalopus (Hesperoscalops) rexroadi tips of the nasals stand 8 behind the anterior edges of the canines. The was described by Hibbard (1941b, c) from Rexroad Locality 2 (early anterior edge of the jugal lies immediately posterior to the caniniform. Blancan) of Kansas. This species is also known from other early The jugal plate slopes ventrad, posteriad, and slightly laterad. The Blancan faunas including Fox Canyon and Rexroad Locality 3 of posterior edge lies posterolateral to M2”. Kansas (Hibbard, 1953a) and Beck Ranch of Texas (Dalquest, 1978). Remarks. The earliest undoubted occurrence of Megalonyx is in It may have given rise to Scalopus aquaticus. S. (H. ) sewardensis is the late Hemphillian at about 6 Ma (Hirschfeld, 1981; Webb and Perrigo, a somewhat larger species described by Reed (1962) from the earliest 1985; Morgan, 2008). It likely evolved from the earlier Hemphillian Blancan Saw Rock Canyon LF of Kansas but it is not considered to genus Pliometanastes. At any rate, Megalonyx was widely distributed be directly ancestral to S. (H. ) rexroadi. S. (H. ) blancoensis from the in North America by middle Pliocene time. The Blancan species, M. late Blancan Blanco LF of Texas (Dalquest, 1975) resembles S. (H.) leptostomus is known from many faunas including several in Texas. It rexroadi but has large, broader teeth and more strongly developed was first described by Cope (1893) based on both premaxillaries, some basal accessory cusps, especially on m3 and with m3 more reduced skull fragments and an upper molariform tooth from the Blanco LF. than m2. S. (H. ) mcgrewi described by Voorhies (1977) from the late Additional specimens from the Blanco site were described by Meade Hemphillian Santee LF of Nebraska is larger than S. (H. ) sewardensis (1945) and Dalquest (1975). The species was redescribed by Hirschfeld and S. (H. ) rexroadi (molars at least 20 per cent longer), and cingular and Webb (1968) based on more complete material including a skull cusps are much more prominent with that on m3 forming a distinct shelf from the Cita Canyon LF. The palate from Proctor Pit C is inadequate approximately as long as the trigonid. Scalopus (Hesperoscalops) sp. is for species identification, however. also known from the late Blancan Belen LF of New Mexico (Morgan Family Mylodontidae and Lucas, 2000b). Paramylodon cf. garbanii Montellano-Ballesteros Order Chiroptera and Carranza-Castañeda, 1986 Family cf. Molossidae Figures 15A-C Figure 14B Referred specimens. Pit B: F:AM 144640, a left upper fourth Referred specimen. Pit C: 4316, edentulous left dentary fragment. molariform tooth. Pit C: F:AM 144641, a left dentary with the second Description. The dentary fragment (Fig. 14B) is broken just and third molariform teeth and alveoli for the caniniform and first anterior to the alveolus of m3. The coronoid process and articular molariform tooth. condyle are intact. The coronoid process is low and angled somewhat Description. The tooth from Pit B (Fig. 15C) is well-preserved anteriorly; it is reduced more than in North American Pliocene and and appears to be a left fifth upper tooth (fourth molariform). It is Pleistocene vespertilionids and about as in molossids (Czaplewski, distinctly bilobate with a wider (20. 0) anterior lobe separated from the written communication, 2015). Measurements: anterior end of m3 narrower (11. 2) posterior lobe by a constriction. Greatest length of the alveolus to posterior edge of articular condyle = 5. 2; jaw depth below tooth is 25. 5. In cross-section, the tooth shows an inner core of vascular tip of coronoid process = 3. 1; length of m3 alveolus = 1. 1. dentine surrounded by an outer layer of harder dentine which is, in turn, Remarks. Fossil bats are rare in Blancan faunas. This dentary was covered by a thin layer of cementum that is partially peeled away. The obtained only after screen washing 39 tons of sediment. maximum tooth height is 57. 9. The left dentary (Figs. 15A-B) from Pit C is broken anterior to Order Xenarthra and beneath the caniniform and first molariform alveoli. The alveolar Family Megalonychidae length of the four teeth is 120. 5. The third tooth (second molariform) is Megalonyx sp. rectangular in occlusal outline and has its long axis oblique to the tooth Referred specimen. Pit C: F:AM 117198 (formerly F:AM 77811), row. It is slightly bilobate with only a slight constriction. Greatest length a palate with the right first molariform, left caniniform, and alveoli for is 24. 0 and greatest width is 14. 4. The last tooth (third molariform) is the remaining upper teeth collected by a Frick party. elongate. The anterior and posterior lobes are directed medially and Description. The specimen is very fragile and poorly preserved. are separated by a narrow constriction. AP length = 43. 4; width of Some of the tooth alveoli are incompletely surrounded by bone. The anterior lobe = 23. 2; width of posterior lobe = 18. 3. The lingual jaw brain case is filled with gray sandstone, and what cranial bones remain depth below the third molariform is 69. 5. The labial jaw depth below have been glued back in place and other repairs appear to have been the second molariform is 65. 8. The jaw width at midsection is 31. 2. made by the museum staff before processing the loan. No measurements Remarks. The largest and probably best known species of this were made by the author. genus is Paramylodon harlani, found in numerous Pleistocene faunas Hirschfeld and Webb (1968, p. 234-235) give the following in North America including Rancho La Brea, California, which description of this specimen: “The widest dimension of the palate is contains a large sample of material described by Stock (1925). A 86. 6 mm across the caniniforms. The palate is constricted posterior to smaller mylodontid sloth has been recognized in several late Blancan the caniniforms to a width of 37. 2 mm. The width across the posterior faunas in Florida, Idaho, and the southwestern United States – usually molariforms is 58. 0 mm; between them it is 16. 8. The posterior narial from a few isolated teeth or a single bone. Akersten (1972) referred two opening lies opposite the last molariforms. The caniniform measures caniniform teeth, a fragmentary edentulous right dentary, and an ungual 29. 8 mm long by 16. 6 wide and has the lingual convexity characteristic phalanx from the Red Light LF of Texas to Paramylodon sp. Hager of advanced Megalonyx. M1 measures 17. 2 by 14. 0 mm. The cheek (1974) referred a second upper molariform tooth from the Donnelly 12 Ranch LF of Colorado to the same genus as well. Robertson (1976) originally described from the early Blancan Arroyo El Tanque site in described a partial skeleton, including the skull and mandible, of a Guanajuato, central Mexico (Montellano-Ballesteros and Carranza- sloth smaller than P. harlani from the Haile XV A LF in Florida that Castañeda, 1986). Authors of recent publications describing mylodont he assigned to the South American genus and species Glossotherium fossils from Blancan faunas in Idaho, Nebraska, California, Arizona, chapadmalensis. A year earlier, Dalquest (1975) referred nine isolated and southwestern New Mexico are divided as to whether the generic teeth from the Blanco LF to Glossotherium near chapadmalense on the assignment should be Glossotherium or Paramylodon. Cassiliano basis of their similarity to teeth in the then unpublished skeleton from (1999) listed Glossotherium as a component of the late Blancan the Haile XVA LF. Vallecito Creek LF in the Anza-Borrego Desert of California whereas McAfee (2009) made a distinction between Pleistocene Schultz and Stout (1948) listed Paramylodon as a component of the Glossotherium of South America and Pleistocene Paramylodon of Blancan age Broadwater LF of Nebraska. Some authors have followed North America based on certain features of the cranium, mandible, Morgan (2008) and referred their fossils to P. cf. garbanii. Notable and dentition. He considered chapadmalense, originally named and records from Arizona cited earlier by Morgan and White (2005) and described as a species of Eumylodon by Kraglievich (1925) from White and Morgan (2005) as Glossotherium are from the 111 Ranch LF the Pliocene of Argentina, to be a member of Glossotherium as had in southeastern Arizona (Galusha et al., 1984); and the Pearson Mesa Hoffstetter (1952) and suggested that this species might be close to LF along the Arizona-New Mexico border (Morgan and Lucas, 2000a). the ancestry of both Glossotherium and Paramylodon. The consensus McDonald and Morgan (2011) summarized the record of Glossotherium among most workers now is that the small mylodont that participated (= Paramylodon) from several late Blancan faunas in southwestern in the Blancan phase of the Great American Biotic Interchange New Mexico. These include an ungual phalanx from the Williamsburg (GABI) gave rise to the larger Paramylodon harlani during the latest LF (Morgan, 2008; Morgan et al., 2011); the distal two-thirds of a left Blancan of North America (McDonald, 1995; McAfee, 2009). Morgan femur from the Pearson Mesa LF (Morgan and Lucas, 2000a; Morgan (2008) referred this Blancan immigrant, previously identified as et al., 2008); and a crushed partial skull with two teeth, a fragment of Glossotherium or “Glossotherium” chapadmalense to Paramylodon a distal humerus, a partial right dentary with fragmentary teeth, and a and suggested that the small late Blancan mylodonts from temperate partial left dentary with associated tooth fragments from the La Union North America might be conspecific with P. garbanii, a small species LF (Vanderhill, 1986; Morgan and Lucas, 2003; Morgan, 2008). It

FIGURE 15. Paramylodon cf. garbanii: A, dorsal view and B, labial view of left dentary with second and third molariforms, F:AM 144641, Pit C; C, occlusal view of upper fourth molariform, F:AM 14464, Pit B. Scale bar = 2 cm. for all specimens. 13 should be noted that McDonald and Morgan (2011) have stated that including 4477b (fig. 7, N3) for which he gave an old catalog number “detailed comparisons have yet to be made among the various Blancan (WTSU 4468g). The correct new number is listed in his list of referred samples of small mylodonts from temperate North America, including specimens, however. New numbers were later assigned when it became New Mexico, and between these samples and cf. garbanii. ” clear that p3s of several species had been lumped under one catalog The left dentary from Proctor Pit C matches in size and morphology number. Hypolagus furlongi is now recognized in Blancan faunas from that of the Haile XV A mandible described by Robertson (1976), and California, Idaho, Nebraska, and Texas (White, 1987, p. 436). the size and shape of the lower second molariform alveolus matches that of the type specimen of Paramylodon garbanii from Mexico. The Hypolagus edensis Frick, 1921 lower third molariform in the Proctor Pit C dentary also matches in size Figures 16J-M and morphology a similar tooth figured by Dalquest (1975) from the Referred specimens. Pit C: 4465, left dentary fragment with Blanco LF, assuming that his figure was reproduced at natural size. In incisor and p3-p4; 4478a, right p3 and 4478b, left p3. Pit D: 4094, right addition, the Proctor Ranch dentary matches in size and morphology p3. several undescribed specimens from Bed 2 (= Unit 2) of the Cita Description. Hypolagus edensis is comparable in size to H. Canyon LF of Texas, listed as Paramylodon sp. by Johnston and furlongi. Both species are smaller than H. gidleyi. A left dentary Savage (1955). Based on these considerations, it seems reasonable to fragment, 4465, is broken posterior to p4. The p3 of this specimen is assign the Proctor Ranch specimens to Paramylodon (= Glossotherium) shown as Figure 16J. The incisor width is 2. 0. The minimum diastema cf. garbanii pending further study and discovery of additional fossils. length is 11. 2. The mental foramen is large (3. 1 long and 1. 5 wide) At any rate, the presence of a small species of Paramylodon (= and dorsolabially placed. Its posterior border is about 0. 6 anterior Glossotherium) in the Red Corral (Proctor Ranch) LF suggests an early to the p3 alveolus. The lingual jaw depth ahead of p3 is about 8. 0. late Blancan age (3. 0-2. 6 Ma) for the fauna and a possible correlation Measurements of the p3s are given in Table 4. The AER is broadly with the lower faunal unit of the Cita Canyon LF. Finally, it should V-shaped and terminates in a narrow, rounded U-shaped tip in the two be noted that Sankey (2002) referred a partial skeleton from the latest teeth in which it can clearly be seen. It appears to be longer than in Blancan age Glenns Ferry Formation in Idaho to Paramylodon harlani those of H. furlongi, which is in agreement with White (1987, p. 437; although she noted that it was smaller than P. harlani from the late White and Morgan, 1995, p. 366) in his emended diagnosis (see below). Pleistocene American Falls LF of Idaho and the Rancho La Brea Fauna The AER: W ratio ranges from 26 to 45 % (N = 4, mean = 32. 2 %). The from California. McDonald (written communication, 2016) states that PER: W ratio ranges from 50 to 52 % (N = 4, mean = 51. 0 %). the fossils are latest Blancan but close to the Irvingtonian boundary and Remarks. The holotype of Hypolagus edensis is a fragmentary might be called Glossotherium chapadmalense/garbanii. dentary with p3-m1 of an immature individual from the Mount Eden LF (Hemphillian) of California (Frick, 1921). White (1987, p. 437) Order Lagomorpha gave an emended diagnosis of the species by stating that “H. edensis is Family Leporidae distinguishable from all other species of Hypolagus by the presence of Rabbits are represented in the Red Corral LF by a diversity of a deep and smooth-sided AER on p3. ” He later added that the species species if not by an abundance of specimens. The fossils consist of is “distinguishable from all other species of Hypolagus by the presence isolated teeth, dentary fragments, and some postcranial material. on p3 of an AER that extends across 25 per cent (N =56) or more of The teeth were studied and identified by the late John A. White, who the width of the tooth, and whose innermost portion is symmetrically made many camera lucida drawings of the occlusal patterns of the U-shaped” (White and Morgan, 1995, p. 366). In his 1987 paper, White diagnostic lower third premolar. Some of these were included in his figured several p3s on page 433 (fig. 7) but none from Red Corral. monumental publications on the Archaeolaginae (White, 1987) and the However, in his list of referred specimens on page 437, WTSU 4468e Leporinae (White, 1991). In the following descriptions, measurements and 4478f are the old catalog numbers that should be replaced by 4478a in millimeters of the lower p3s are given using the method illustrated in and 4478b, respectively. Hypolagus edensis is now recognized from the White (1987, p. 426) for the Archaeolaginae and in White (1991, p. 68) Hemphillian of Arizona and California and the Blancan of California, for the Leporinae. Abbreviations used for the following measurements Idaho, Nevada, Texas, and Washington (White, 1987, p. 437). are: anteroposterior length (AP), width (W), depth of anteroexternal reentrant (AER), maximum depth of posteroexternal reentrant (PER), Hypolagus gidleyi White, 1987 depth of posteroexternal reentrant to point of constriction in leporines Figure 16N (PERc), thick enamel on anterior border of the posteroexternal Referred specimens. Pit C: 4468a, b, c, and d, four left p3s. reentrant (TH), thin enamel on posterior border of the posteroexternal Description. The teeth are large. Near the top of 4468a (Fig. 16N), reentrant (TN), anterior reentrant (AR), anterointernal reentrant (AIR), the enamel has been eroded so that measurements were made at the posterointernal reentrant (PIR). See Figure 16A. base of the tooth. Measurements of the p3s are given in Table 4. AER is Subfamily Archaeolaginae not as deeply incised as in Hypolagus edensis. The AER: W ratio ranges Hypolagus furlongi Gazin, 1934a from 15 to 25 % (N = 4, mean = 18. 0 %). PER is straight and deeply Figures 16B-I incised with no deflection at its inward end. The PER: W ratio varies from 48 to 75 % (N = 4, mean = 59. 0 %). Referred specimen. Pit C: 4463, right dentary fragment with p3- Remarks. The holotype of Hypolagus gidleyi is a complete m1; 4464, left dentary fragment with p3-m3; 4467, complete left lower skull of an immature individual from the embayment south of the dentition; 4477, three left and two right p3s. Pit D: 4093a, left p3. Horse Quarry, Hagerman LF (Blancan) of Idaho. White (1987, p. 434) Description. A right dentary fragment, 4463, contains p3-m1 and compared H. gidleyi with other species of Hypolagus. He noted that “H. a broken incisor 3. 5 wide. The p3 of this specimen is shown as Figure gidleyi differs from H. edensis in a markedly less well incised AER and 16B. The minimum diastema length is 13. 3. The mental foramen is markedly larger size. From H. furlongi it differs in its markedly larger large with broken edges and is dorsolabially placed. Its posterior border size”. He figured one p3 from Red Corral, correctly numbered as WTSU is 1. 3 anterior to the p3 alveolus. Lingual jaw depth ahead of p3 = 9. 1. 4468b, on page 433 (fig. 7, C3) of his 1987 paper. White (1987, p. 434) The left dentary fragment, 4464, of a small individual is broken anterior stated that Hypolagus gidleyi is now recognized from the “Hemphillian to p3 and posterior to m3. The p3 of this specimen is shown as Figure of Texas and New Mexico, Blancan of Idaho, Nebraska, Texas, and 16C. The left p3, 4093a (Fig. 16I), from Pit D resembles those from Washington. ”The Texas Hemphillian record is Coffee Ranch which Pit C. Measurements of the p3s are given in Table 4. In all of the p3s, White in the previous paragraph erroneously listed as Blancan. The the PER is straight and directed inward nearly perpendicular to the AP Nebraska record is from Oshkosh which is Hemphillian and not Blancan line. TH is straight to slightly wavy and extends the entire PER distance as White stated. The New Mexico specimen is Blancan and is from the but may show slight inward thinning in some cases. The AER: W ratio Albuquerque Basin and not from the Clarendonian-Hemphillian age ranges from 19 to 32 % (N = 9, mean = 25. 0 %. The PER: W ratio Chamita Formation which is restricted to the Espanola Basin of north- ranges from 45 to 57 % (N = 9, mean = 52. 7 %). central New Mexico– see discussion in Lucas and Williamson (1993, p. Remarks. The holotype described by Gazin (1934a) is a right 6). H. gidleyi is also recognized from the early Blancan Panaca LF of dentary with i-m2 from the late Blancan Grand View LF of Idaho. Nevada (Mou, 2011b). White (1987, p. 436) gave an emended diagnosis of the species and Hypolagus is represented in the Red Corral LF by three species: comparisons with other species of the genus and noted that it is a large species, H. gidleyi, and two smaller species, H. furlongi and comparable in size to Hypolagus edensis but differs from it in having H. edensis. Some workers might argue that only one small species a significantly shallower AER. He figured several p3s on page 433 existed in the Red Corral LF and that H. furlongi and H. edensis are 14 conspecific. It would seem more likely that the two species are distinct Pewelagus dawsonae White, 1984 and that one of them may have been misidentified in the Red Corral Figure 16O sample. White (1987) recognized 12 species of Hypolagus in the Referred specimen. Pit C: 4476, left p3. Late Tertiary radiation and proliferation of the genus. In addition to Description. Measurements of the p3 (Fig. 16O) are given in p3 patterns, P2 patterns, and characters of the skull, when available, Table 4. The AER: W ratio is 27. 3 % and the PER: W ratio is 46. 0 %. were used to separate species. In many faunas two, three, or even four PER is mostly straight but shows a very slight posterior deflection of species of Hypolagus have been recognized e. g. H. gidleyi, H. furlongi, the tip of TH. H. edensis, and H. voorhiesi are recognized from the Blancan age Nine Remarks. The holotype of this species and the genus is a cranium Foot Rapids LF of Idaho (White, 1987) and Mou (2011b) reported H. from the Arroyo Seco LF (Blancan) in Anza-Borrego Desert State edensis, H. tedfordi, H. cf. ringoldensis, H. gidleyi, and H. regalis from Park, San Diego County, California, which White (1984) stated was the early Blancan Panaca LF of Nevada. Future studies may warrant the near the size of Sylvilagus bachmani. White (1984, p. 47; 1987, p. 441- synonymizing of some species but such a venture is beyond the scope 442) referred several dentaries and lower teeth. In his 1987 paper, he of this paper.

FIGURE 16. Rabbit lower p3s. Pit C unless otherwise stated. Figures are from camera lucida drawings made by John A. White here magnified 24. 6 to 28 times. Actual tooth measurements are given in the text and Table 4. A, Terminology used in text: AR = anterior reentrant; AER = anterior external reentrant; PER = posterior external reentrant; AIR = anterior internal reentrant; PIR = posterior internal reentrant; TH = thick enamel; TN = thin enamel; not shown: PERc = length of PER to point of constriction. Hypolagus furlongi: B, right, 4463; C, left, 4464; D, left, 4477a (formerly 4468d); E, left, 4477b (formerly 4468g); F, left, 4477c (formerly 4468i); G, right, 4477d (formerly 4468c); H, right, 4477e (formerly 4468h); I, left, 4093a, Pit D. Hypolagus edensis: J, left, 4465; K, right, 4478a (formerly 4468c); L, left, 4478b (formerly 4468f); M, right, 4094, Pit D. Hypolagus gidleyi: N, left, 4468b. Pewelagus dawsonae: O, left, 4476 (formerly 4468a). Sylvilagus hibbardi: P, right, 4475a (formerly 4468n); Q, right, 4092, Pit D. 15 TABLE 4. Measurements (in mm) of rabbit p3s from Red Corral sites. and 4475a (Fig. 16P) are given in Table 4. Three broken p3s were not Abbreviations are explained in text and figure 16. measured. The immature p3, 4469, was not measured but shows slight development of AR, AIR, and PIR. AP W AER AER/W PER PER/W PERc PERc/PER The most complete specimen from Pit D, 4092, is a right dentary H. furlongi with i, p3-m2. The p3 is shown in Figure 16Q and the dentary in Figure 4463 2. 6 2. 2 0. 6 27. 30% 1. 1 50% 17A. The incisor width = 2. 6. The diastema is approximately 9. 0. The 4464 2. 1 2 0. 4 20% 0. 9 45% mental foramen is smaller than in Hypolagus (1. 3 long and 0. 8 wide) 4467 2. 1 1. 8 0. 4 22% 1 55. 60% and is more laterally placed. Its posterior border is about 1. 8 anterior to 4477a 2. 4 2. 2 0. 6 27. 30% 1. 1 50% the p3 alveolus. Lingual jaw depth ahead of p3 is 8. 5. Measurements 4477b 2. 4 2. 1 0. 5 24% 1. 2 57% of the p3 (Fig. 16Q) are given in Table 4. There is a slight, crenulated 4477c 2. 1 1. 9 0. 4 21% 1 52. 60% AR. The AER: W ratio is 28. 0 %, the PER: W ratio is 72. 0 %, and the 4477d 2 1. 9 0. 6 32% 1 53% PERc:PER ratio is 61. 1%. 4477e 2. 5 2. 1 0. 4 19% 1. 2 57% A left dentary fragment, 4199, contains p3-m1. On the p3, AR is 4093a 2. 4 2. 2 0. 7 32% 1. 2 54. 50% slightly developed. The AER: W ratio is 22. 7 %, PER: W is 72. 7 %, Mean 2. 3 2 0. 6 24. 96% 1. 1 52. 70% and PERc: PER is 50. 0 %. A slight crenulated AR is preserved on three H. edensis other teeth. Measurements of the p3s are given in Table 4. 4465 2. 5 2. 2 0. 6 27. 30% 1. 1 50. 00% For the entire sample, the AER: W ratio ranges from 14. 3 to 28. 4478a 2. 7 2.3 0. 6 26. 00% 1. 2 52. 00% 6 % (N = 8, mean = 21. 8 %), PER: W ranges from 64. 3 to 74. 1 % (N 4478b 2. 6 2. 3 0. 7 30. 40% 1. 2 52. 00% = 7, mean = 69. 9 %), and PERc: PER ranges from 50. 0 to 66. 7 % (N 4094 2. 3 2 0. 9 45. 00% 1 50. 00% = 7, mean = 58. 8 %). Mean 2. 5 2. 2 0. 7 32. 18% 1. 2 51. 00% Some of the upper P2s from Pit D contain three anterior reentrants H. gidleyi and probably belong to Sylvilagus hibbardi, whereas others from both 4468a 3. 2 3. 1 0. 5 16. 00% 1. 5 48. 00% pits have a deep main anterior reentrant (MAR) and a shallow external 4468b 3. 2 3. 1 0. 5 16. 00% 1. 7 55. 00% anterior reentrant (EAR) and probably belong to Hypolagus. 4468c 2. 7 2. 4 0. 6 25. 00% 1. 8 75. 00% Remarks. The holotype of this species is a left dentary fragment 4468d 3. 1 2. 6 0. 4 15. 40% 1. 5 58. 00% with p3-m3 from the Vallecito Creek LF (late Blancan to Irvingtonian), Mean 3 2. 8 0. 5 18. 00% 1. 6 59. 00% Anza-Borrego Desert State Park, San Diego County, California (White, P. dawsonae 1984). White (1984, 1991) referred many dentary fragments to this 4476 2. 5 2. 2 0. 6 27. 30% 1 46. 00% species. In his 1991 paper he listed all of the Red Corral specimens with S. hibbardi currently correct catalog numbers but did not designate from which 4466 3. 2 2. 8 0. 8 28. 60% 1. 8 64. 30% 1 55. 60% locality the specimens were taken. It should be noted, however, that in 4475a 3 2. 7 0. 5 18. 50% 2 74. 10% 1. 2 60. 00% his figure 9, D4 on page 77, specimen 4092 is reversed and is incorrectly 4092 3. 2 2. 5 0. 7 28. 00% 1. 8 72. 00% 1. 1 61. 10% given the number 4091 in the figure caption but the correct number, 4199 2. 2 2. 2 0. 5 22. 70% 1. 6 72. 70% 0. 8 50. 00% 4092, is used in the text. It should be noted also that the specimens from 4177a 2. 9 2. 3 0. 6 26. 10% 1. 7 73. 90% 1. 1 64. 70% Cita Canyon listed as WTSU 4500a and 4500b have been assigned new 4177b 3 2. 8 0. 4 14. 30% 1. 8 64. 30% 1. 2 66. 70% catalog numbers, which are 4623 and 4624. White (1984) reported that 4177c 3 2. 7 0. 5 18. 50% 57 % of his sample of p3s showed the ”pro-Sylvilagus” pattern in which 4177d 2. 4 2. 2 0. 4 18. 20% 1. 5 68. 20% 0. 8 53. 30% the PER joins through a constriction, which, in later Sylvilagus and Mean 2. 9 2. 5 0. 6 21. 79% 1. 7 69. 93% 1 58. 77% Lepus would be an enamel island or lake. Sylvilagus hibbardi is now recognized from the Blancan of Arizona, California, and Texas and the included the Red Corral tooth for which he used the old catalog number, Irvingtonian of California, Texas, and Sonora, Mexico. WTSU 4468a (the new correct number is 4476), but did not figure the specimen. In his 1984 paper, he compared the genus and species Pliopentalagus sp. with species of Hypolagus. He noted that the p3 is small and that Figures 17B-D “crenulations in the anteroexternal reentrant sets Pewelagus dawsonae Referred specimens. Pit D: 4095a, right p3; 4095b, left p3; and apart from Hypolagus furlongi” and that “the p3 in H. edensis Frick 4095c, left p3. (1921) has a size and pattern comparable to that in P. dawsonae and Description. Three lower p3s possess five reentrants and are may be referable to this genus” (p. 50). In his 1987 paper, however, he here assigned to the genus Pliopentalagus. The reentrants are filled maintained the integrity of both taxa. White (1984, p. 53) stated that with cementum. In 4095a and 4095b (Figs. 17B-C), the AR is shallow “the structure of the cranium in P. dawsoni suggests an erect posture but broad with three crenulations (folds) in the former and two in the similar to that in Sylvilagus and Brachylagus……based on a pistol grip- latter. In 4095c (Fig. 17D), the AR is narrower but deeper and has two like flexion of the posterior end of the cranium.” He went on to say crenulations. The AIR is small and uncrenulated in all three teeth. In (p. 54-55) that “the flexion of the posterior end of the cranium, the 4095c, it is 0. 2 deep. The AER in 4095a is wide with 3 very shallow greatly enlarged tympanic bullae, and narrow choanae suggest that P. crenulations and a narrow, deeper one that extends about two-fifths of dawsonae lived in burrows and escaped snakes and owls in a manner the way across the tooth. In 4095b, the AER is narrow and deep and similar to Dipodomys (Webster, 1962).” Pewelagus dawsonae is now in 4095c it is externally wider with a central, narrow, deep fold. The recognized in the Blancan of California, Nevada, and Texas (White, PIR in 4095a is externally wide with a central fold that extends nearly 1987, p. 443). one-third of the way across the tooth. In 4095b the PIR is externally Subfamily Leporinae narrower but broadens to a fold that extends over one-third of the way Sylvilagus hibbardi White, 1984 across the tooth. In 4095c, a pedomorphic form, the PIR is narrow and Figures 16P-Q; 17A connects with the PER about half way across the tooth. In 4095a, the Referred specimens. Pit C: 4466, left dentary fragment with p3- PER is externally broad but narrows medially to extend three-fifths p4; 4475, four p3s; 4469, immature, unworn left p3. Pit D: 4092, right of the way across the tooth where it divides into two folds which are dentary with incisor and p3-m2; 4177, four left and five right p3s; 4199, narrowly separated from the PIR. In 4095b, the PER divides into two left dentary fragment with p3-m1. folds, the anterior of which extends over half way across the tooth Description. The most complete specimen from Pit C is a left where it is narrowly separated from the PIR. In 4095c, the pedomorphic dentary fragment, 4466, which contains p3-p4 and very weathered form (Fig. 17D), the PER is somewhat crenulated and joins the PIR dentine. No AIR or PIR is present on the p3. The AER: W ratio is 28. about half way across the tooth. In 4095a and 4095b, the enamel is very 6 %. The PER: W ratio is 64. 3 %. The PER enamel is crenulated and thick on the posterior external surface of the tooth and on the anterior PER becomes constricted at 1. 0 depth (PERc) but then expands and is surface of PER as well as on the exterior surface between AR and AER. deflected anteriorly for the remainder of its depth (the “pro-Sylvilagus” In 4095c, very thick enamel is present on the anterior surface of the pattern of Hibbard, 1963). The PERc: PER ratio is 1. 0:1. 8 or 55. 6 %. conjoined PER and PIR as well as across the posterior surface of the No isolated enamel lake or island is present on any of the p3s examined; tooth. Length and width of the teeth are 3. 7 and 3. 0 in 4095a; 3. 3 and the tooth morphology is very similar in the other p3s. In the single right 2. 7 in 4095b; 3. 3 and 2. 5 in 4095c. p3, 4475a, the AER: W ratio is 18. 5 %, the PER: W ratio is 74. 1 % Remarks. According to Tomida and Jin (2002), the genus and the PERc: PER ratio is 60. 0 %. Measurements of the p3 of 4466 Pliopentalagus is ancestral to the living genus Pentalagus. Fejfar 16 (1961) described Alilepus dietrichi from Slovakia (= Slovak Socialist “Spermophilus” rexroadensis (Hibbard) from Rexroad Locality 3 Republic) based on several isolated teeth. Later, Gureev (1964) gave the (Hibbard, 1941b, c; Hazard, 1961) or the Quaternary Otospermophilus generic name Pliopentalagus to a new species from Moldavia (based variegatus (Erxleben). also on a few isolated teeth), as well as to Alilepus dietrichi. Although In the dentary fragment, 4317, p4 is 2. 7 long and 2. 7 wide (Fig. a few additional fossils were added from a few isolated localities in 18E). The protolophid is absent. The protoconid and metaconid are China, fossil material of Pliopentalagus remained very limited until a subequal in size and separated by a notch. The metaconid is slightly discovery in Huainan, Anhui Province, China by Tomida and Jin (2002). higher than the protoconid. The m1 is 2. 6 long and 3. 1 wide and is This discovery includes not only teeth but also a number of skulls, jaws, parallelogram-shaped in occlusal view. and postcranial bones that range in age from latest Miocene (about 6 In unworn first and second upper molars, the metaconule Ma) to late Pliocene (about 3 Ma), thus making it possible to trace (metaloph) does not join the protocone but is separated from it by a the morphological changes of the Pliopentalagus-Pentalagus lineage sulcus. Mesostyles are present or absent. The parastyle does not bend for about the last 6 million years. There is a progressive increase in sharply to join the protocone, and the occlusal outline of the teeth is complexity of the reentrant folds through time. It is also possible to broadly triangular. These characters suggest that they may belong to consider the relationships of other genera possessing p3s with all five the genus Otospermophilus. There are four M3s in the sample. In one, reentrant angles such as Pronolagus, Aztlanolagus, and Trischizolagus there is a fully developed metaloph extending from the protocone to to the genus Pliopentalagus. The three p3s from the Red Corral LF the labial edge of the tooth; in two others, there is a low metaconule most closely resemble illustrations of Pliopentalagus dajushanensis cusp, and, in the fourth, the metaconule and metaloph are absent. The and P. anhuiensis described by Tomida and Jin (2009). These were posterior cingulum of M3 does not bend sharply posteriad. In the lower listed earlier as P. spp. B and C from the early and late Pliocene of molars, the metaconid is larger and slightly higher than the protoconid China, respectively (Tomida and Jin, 2002, p. 105). However, because and is separated from it by a notch (Fig. 18F). No P3s are present. of the variation in complexity of the reentrant folds, I am reluctant to Remarks. A number of ground squirrels assigned to Spermophilus assign a species name to these specimens. The Red Corral teeth may (sensu lato) of different sizes have been described from Blancan faunas well represent the first known Pliocene (Blancan) occurrence of this in the United States on the basis of lower jaws and upper dentitions. genus in North America unless a single right p3 from the 111 Ranch Detailed identification of isolated fossil ground squirrel teeth is nearly LF, Arizona, described as Aztlanolagus agilis (Downey, 1962; Tomida, impossible, and is made more difficult by the recent recognition 1987), turns out to be assignable to Pliopentalagus. as numerous genera (Helgen et al., 2009) of species that were once Order Rodentia assigned to the genus Spermophilus. Assignment of even complete Family Sciuridae dentitions to one of the extant generic groups is difficult and probably Tribe Marmotini unwise considering the generalized nature of the fossils. Some of the Genus and species indet. - large described characters occur in more than one genus. Figures 18E-F Tribe Marmotini Referred specimens. Pit C: 4317, left lower dentary fragment, Genus and species indet. - medium p4-m1; 4318, isolated teeth. Pit D: 4021, isolated teeth. Figure 18G Description. Ground squirrels are represented in the Red Corral Referred specimens. Pit C: 4319, isolated teeth. Pit D: 4022, LF almost entirely by isolated teeth that fall into three distinct size isolated teeth. categories and represent at least three species. A large species is Description. A medium-sized ground squirrel is represented by represented by a lower dentary fragment and several teeth in different teeth that are narrower transversely than those of Urocitellus richardsonii wear stages. The teeth are the size of those of a small individual of (Sabine) and Poliocitellus franklinii (Sabine) but larger than those of

FIGURE 17. Sylvilagus hibbardi: A, right dentary with incisor, p3-m2, 4092, Pit D. Pliopentalagus sp. : B, right p3, 4095a; C, left p3,. 4095b; D, left p3, 4095c; - all from Pit D. Figures of the Pliopentalagus p3s are from camera lucida drawings made by John A. White here magnified 25 to 26 times. Actual tooth measurements are given in the text. 17

FIGURE 18. Procastoroides sweeti: A, right DP4, 4032, Pit D; B, 3 immature teeth, 4032, Pit D; C, right M1 or M2, 4023, Pit D; D, upper right and left dentitions, 4027, Pit D. Ground squirrel (large): E, left dentary fragment, p4-m1, 4317, Pit C; F, right lower tooth, 4021, Pit D. Ground squirrel (medium): G, right lower tooth, 4022, Pit D. Geomys (Nerterogeomys) cf. minor: H, right dentary with incisor, p4-m1, 4324, Pit C; I, left dentary with incisor, p4-m3, 4321, Pit C. Ictidomys tridecemlineatus (Mitchill) and Xerospermophilus spilosoma the metaloph (and metaconule) are absent, and a shallow basin occurs (Bennett) (Fig. 18G). The teeth are equal in size or slightly larger than behind the protoloph. The posterior cingulum does not bend sharply those of “Spermophilus” howelli (Hibbard) from Rexroad Locality 3 posteriad. (Hibbard, 1941b, c). In slightly worn P4, M1, and M2, the metaloph Tribe Marmotini is either separate from the protocone or joins it weakly. Mesostyles Genus and species indet. – small are generally absent. The parastyle does not bend sharply to join the protocone, and the teeth are broadly triangular in occlusal view. In M3, Referred specimens. Pit C: 4320, isolated teeth. 18 Description. At least one species of small ground squirrel is present present and persist to the base of the tooth. The AP tooth thickness is 9. in Pit C. The teeth are similar in length but narrower transversely than 0; AP L is 10. 0; and TW is 9. 5. those of Ictidomys tridecemlineatus. The upper molars are triangular WT 4138 is a right m1 or m2. The occlusal pattern is S-shaped. in occlusal outline with narrow to broad V-shaped trigons. In most, the The anterior lophid (3) is crescentic with the convex side anterior parastyle bends sharply to join the protocone although in a few teeth, and is inflated lingually. The median lophid (2) is straight, uninflated, the parastyle is less prominent and merges without change of direction. and trends anterolabially. The posterior lophid (1) is slightly inflated Mesostyles are generally absent, and the metaloph (metaconule) labially and trends anterolabially. The mesoflexid trends anteriorly, and is separated from the protocone by a sulcus. The lower molars are its termination is broken. The hypoflexid trends posterolingually and rhomboidal in shape in occlusal view. its enamel termination is slightly rounded. There are no pseudostriids. Remarks. The presence of more than one species of ground The mesostriid and hypostriid are present and persist to the base of the squirrel is not uncommon in Blancan faunas; frequently, a large and a tooth. The AP tooth thickness is 8. 9; AP L is 10. 0; and TW is 10. 4. small species occur together. UMMP 42632 is a weathered right m1 or m2. The occlusal pattern Family Castoridae is S-shaped. The anterior lophid (3) is slightly crescentic with the convex Procastoroides sweeti Barbour and Schultz, 1937 side anterior and is inflated lingually. The median lophid (2) is straight, Figures 18A-D uninflated and trends anterolabially. The posterior lophid (1) is slightly inflated and trends anterolabially. The mesoflexid trends anterolabially Referred specimens. Pit D: 4023, right M1 or M2; 4024, right and terminates labially at the tooth wall to produce a pseudomesostriid. M3; 4025, right M1 or M2; F:AM 65208, right M1 or M2; 4138, The hypoflexid trends posterolingually and terminates lingually at the right m1 or m2; UMMP 42632, right m1 or m2; 4032, deciduous tooth wall to produce a pseudohypostriid. The mesostriid and hypostriid premolars and immature molars; 4026, incisor fragments; 4027, skull are present and persist to the base of the tooth. The AP tooth thickness is fragments including upper dentitions and an associated atlas; 4028, 9. 3; AP L is 10. 0; and TW is 10. 2. right astragalus; 4029, phalanges; 4030, caudal vertebra; 4031, patella; Among the isolated teeth, 4032, are several immature molars and UCMP 43406, distal right humerus. deciduous premolars (Figs. 18A-B). In two lower left m1s or m2s, Description. Terminology used in tooth descriptions is that of the anterior lophid (4-3) is partially divided lingually by a shallow Stirton (1935), Shotwell (1955), and Woodburne (1961). A slightly paraflexid, and the parastriid extends only to a depth of about 2. 0 below modified terminology was used by Martin (2014) for Dipoides in the occlusal surface. The hypoflexid is deep and narrow, and there is a which he replaced the names of lophs (-ids) with numbers. Lophs were small hypofossetid situated within the dentine between the termination numbered consecutively from 1 (anterior) to 4 (posterior) on each of the hypoflexid and the lingual tooth wall. upper cheek tooth and lophids were numbered consecutively from There are two well-worn right DP4s almost completely 1 (posterior) to 4 (anterior) on each lower cheek tooth. Loph 4 and surrounded by enamel. In the less worn of these, a narrow paraflexus lophid 4 are best seen on P4 and p4 respectively. Mature molars usually extends nearly half way across the tooth and is inflected anteriorly near display 3 lophs and 3 lophids (1, 2, and 3). This system is here applied its termination. A broad, well-developed hypoflexus extends over half to Procastoroides and Martin’s numbers are given in parentheses way across the tooth nearly meeting the paraflexus and leaving only following the loph (-id) name for the sake of future comparisons. a narrow connection between the anterior (1) and median (2) lophs. WT 4023 is a right M1 or M2 (Fig. 18C). The anterior loph (1) A narrow mesoflexus extends nearly across the entire tooth and is is uninflated and moderately crescentic with the convex side anterior. inflected posterolingually at its mid-point. The posterior loph (3-4) is The median loph (2) is slightly inflated anteriorly with the posterior oval-shaped and contains a small metafossette indicating the probable enamel wall nearly straight. The posterior loph (3) is inflated labially. presence of a metaflexus in earlier wear. The tooth has a large medial The hypoflexus terminates flat against a thin labial enamel wall but root and two small labial roots. interrupts the wall about 3. 5 below the occlusal surface to create a There are four dp4s (three rights and one left). The occlusal pattern pseudohypostria. The mesoflexus trends posterolingually and interrupts is basically S-shaped with well-developed mesoflexids and hypoflexids. the lingual enamel wall about 0. 3 below the occlusal surface to create In one tooth, a shallow paraflexid extends about half way across the a pseudomesostria. The hypostria and mesostria are present and persist tooth to partially divide the anterior lophid. In another, the paraflexid to the base of the tooth. The AP tooth thickness is 7. 7; AP L is 8. 9; extends entirely across the tooth to isolate an oval-shaped first anterior and TW is 8. 9. lophid from the second anterior lophid, which opens broadly into the WT 4024 is a right M3. The anterior loph (1) is slightly inflated median lophid. In the latter tooth the termination of the hypoflexid is anteriorly with the labial end inflected posteriorly. The median loph pinched off to isolate a small fossettid near the connection between the (2) and the first posterior loph (3) are uninflated and crescentic with median and posterior lophids. All dp4s possess two roots – one anterior the convex side anterior. The second posterior loph (4) is oval-shaped and one posterior. and broken near the occlusal surface. The hypoflexus terminates as a WT 4026 consists of several incisor fragments, the largest being slightly rounded enamel loop but interrupts the labial enamel tooth wall a part of a curved upper incisor that has a maximum width of 15. 5. about 0. 8 below the occlusal surface to form a pseudohypostria. In the The anterior surface is rounded and smooth and lacks any longitudinal mesoflexus, the enamel termination wall is flat and abuts the lingual grooves. enamel wall of the tooth. In the metaflexus, the enamel termination wall The skull fragments, 4027, are badly weathered and cannot be is rounded and slightly separated from the lingual enamel wall of the easily reassembled. They include parts of the skull roof, zygomatic tooth. The hypostria, mesostria, and metastria are present and persist to arches, and palate. Cheek teeth present include left and right M1-M3, the base of the tooth. The AP tooth thickness is 8. 8; AP L is 9. 5; and but they are too weathered to provide useful measurements and there TW is 8. 5. is unequal wear between the left and right teeth (Fig. 18D). Associated WT 4025 is a right M1 or M2. The lophs are uninflated. The with the skull are the atlas vertebra and a thoracic vertebra. anterior loph (1) is crescentic with the convex side anterior; the median Other postcranial material includes the distal end of a right loph (2) is straight; and the posterior loph (3) is slightly crescentic with humerus, UCMP 43406, in which the ulnar facet is 24. 6 wide. A patella, the concave side anterior. The enamel termination of the hypoflexus 4031, measures 28. 3 by 22. 2. Measurements of a modern Castor is nearly flat, and there is no pseudohypostria. The mesoflexus trends patella are 21. 2 by 16. 0. A right astragalus, 4028, has a maximum posterolingually and interrupts the lingual tooth wall to form a AP L of 28. 1 and is 27. 6 wide. It is larger than that of a modern pseudomesostria. The hypostria and mesostria are present and persist Castor (AP L = 24. 0; TW = 22. 5) but smaller than two right astragali, to the base of the tooth. The AP tooth thickness is 8. 9; AP L is 9. 7; and UMMP 57400 (AP L= 34. 6) and UMMP 57401 (AP L = 32. 0 and TW TW is 11. 3. = 31. 5) from the Sand Draw LF. of Nebraska (Skinner et al., 1972). F:AM 65208 is a right M1 or M2. The anterior loph (1) is very An unnumbered right navicular is 25. 2 wide. Also present are several slightly inflated lingually and slightly crescentic with the convex side isolated metatarsals and phalanges and a caudal vertebra. anterior. The median loph (2) is uninflated with the walls slightly Remarks. Procastoroides is a genus of beavers of large body size, crescentic. The anterior wall of the posterior loph (3) is straight, whereas most of which were about two-thirds the size of species of Castoroides. the posterior wall is convex posteriorly. The hypoflexus terminates flat Procastoroides is known from the Blancan of North America, where against a thin labial enamel wall but interrupts the wall about 1. 4 below three species are recognized (Xu, 1995; Korth, 2002). P. sweeti is a the occlusal surface to create a pseudohypostria. The mesoflexus trends Great Plains species that was first described by Barbour and Schultz posterolingually and terminates flatly against the lingual enamel wall. (1937) from the Broadwater LF of Nebraska. It is also known from A pseudomesostria is not developed. The hypostria and mesostria are the Sand Draw and Mullen I local faunas of Nebraska, the Delmont 19 LF of South Dakota (Martin and Harksen, 1974), and the Rexroad of 40 adult p4s from Pit C is 1. 83 (1. 7-2. 0) and of 22 p4s from Pit Locality 3, Deer Park, Dixon, and White Rock local faunas of Kansas D is 1. 8 (1. 5-2. 1). The reentrant pattern varies from U-shaped to in addition to the Red Corral LF of Texas (Kurtén and Anderson, 1980). bluntly V-shaped. In adult p4s, the enamel pattern is interrupted by The genus is also represented by undescribed teeth from the Bivins Pit dentine tracts on the labial and lingual surfaces of both protolophid and 2 LF site located 11 km (7 miles) south of Channing in Oldham County, metalophid. There are 46 adult P4s from Pit C. The average width of Texas (R. Tedford, written communication, 1986). Eocastoroides lanei the metaloph is 1. 75 (1. 6-1. 9). Seven P4s are of young individuals Hibbard from Deer Park and Rexroad Locality 3 is a synonym (Hibbard, and have continuous enamel bands around the occlusal surface. With 1938). A distinguishing character is the absence of crenulations on wear, this pattern will be interrupted by labial and lingual dentine tracts the enamel of the incisors. Shotwell (1970) described Procastoroides on the protoloph and the enamel on the posterior face of the metaloph idahoensis from the late Blancan Jackass Butte locality of the Grand will disappear as it has in all but one of the adult P4s in the sample. View LF of Idaho and referred to this species two partial skeletons A single left adult P4 has a band of enamel running the length of the from Castle Butte (Grand View LF) and miscellaneous specimens from tooth on the labial one-third of the posterior surface of the metaloph Shoofly Creek, Idaho. This species has also been recognized inthe and separated from the labial reentrant enamel by a thin dentine tract. Seneca LF of Nebraska (Martin and Schultz, 1985). It is distinguished The average TW of 14 P4s from Pit D is 1. 7 (1. 5-1. 9). The reentrants by crenulations or longitudinal grooves on the enamel of the incisors are squared, U-shaped or bluntly V-shaped. The M1s are like those in and, for this reason, Procastoroides is considered by some workers to the palate, 4325. be ancestral to Castoroides. Woodburne (1961) did not believe this to Remarks. Czaplewski (1990) noted that, based on Hibbard’s be the case based on the absence of crenulations on the incisors of P. redefinition of Nerterogeomys, six species can be assigned to that sweeti, the only known species at the time. Flynn and Jacobs (2007) subgenus, Geomys minor (smallest), G. persimilis, G. smithi, G. suggest that P. idahoensis could be regarded as an early species of anzensis, G. garbanii, and G. paenebursarius (largest). He pointed Castoroides. Zakrzewski (1969) described Dipoides intermedius from out, however, that intraspecific morphological measurements of the early Blancan Hagerman LF of Idaho. He considered it to be the modern pocket gophers can be highly variable and that interspecific largest known species of Dipoides. Xu (1995) transferred this species measurements may overlap. In addition, he noted that many authors to Procastoroides. have documented pronounced age variation and sexual dimorphism in size in modern pocket gophers. Similarly, he concluded that size may Family Geomyidae not be the best indicator of species differences among extinct pocket Geomys (Nerterogeomys) cf. minor Gidley, 1922 gophers, and that some fossil species might represent age variants or Figures 18H-I different sexes of the same widespread species. Therefore, size must be Referred specimens. Pit C: 4321, left dentary with incisor and p4- used with caution, and only adult measurements should be compared. m3; 4322, left dentary with incisor and p4-m3; 4323, left dentary with The dentaries from the Red Corral LF differ from those of Geomys incisor and p4-m2; 4324, right dentary with incisor and p4-m1; 4325, (Nerterogeomys) smithi Hibbard (1967) from the Fox Canyon LF of palate with right and left P4-M1; 4326 (in part), isolated teeth. Pit D: Kansas in having a shorter diastema, except for 4321, and a shorter 4033 (in part), isolated teeth. occlusal length of the tooth row. The occlusal length of the paratype Description. All of the dentaries are from adults and are broken of G. (N. ) smithi is shorter than that of the holotype and only slightly just posterior to the cheek teeth preserved in each. In addition, most greater than that of the Red Corral specimens, but it is from a younger of the bone labial to the cheek teeth is missing, except in 4321, the individual than the holotype. most completely preserved specimen, in which the anterior part of the Three of the four Red Corral specimens are smaller in all masseteric crest can be seen (Fig. 18I). In all of the dentaries, enough of measurements than those of Geomys (N. ) paenebursarius from the the labial wall is preserved to show that the mental foramen lies 1. 5 to 2. Hudspeth (Strain, 1966) and Red Light (Akersten, 1972) local faunas 3 below and slightly anterior to the anterior extremity of the masseteric of west Texas. The measurements of 4321 compare closely with those crest, which is the criterion for assignment to Nerterogeomys (Gazin, of the holotype and paratype specimens from Hudspeth. However, 1942) that Hibbard (1967) redefined and changed in rank from genus 4321 is probably an older individual while, according to Akersten to subgenus. That portion of the dentaries containing the masseteric pit (1972, p. 16), the types of G. (N. ) paenebursarius appear to be younger or fossa is missing in all specimens. In 4321 enough of the labial wall individuals (with shorter diastemas) than those from the Red Light LF. of m3 is preserved to indicate that a deep pit was present, although its Considering the fact that the size of gopher jaws increases with age, it exact shape and depth are unknown because the base of the ascending seems more reasonable to attribute the greater diastemal and occlusal ramus is missing. In the p4s the enamel is interrupted by dentine tracts lengths of 4321 to age, sexual, or individual variation than to postulate on the internal and external surfaces of both the protolophid (anterior the existence of a second and larger species of Nerterogeomys in the lophid) and the metalophid (posterior lophid). The reentrants are Red Corral LF. U-shaped to bluntly V-shaped or squarish in occlusal view and are The Red Corral dentaries, with the exception of 4321, compare filled with cementum. The protolophid is sub circular and longer than most favorably with the holotype of Geomys (N. ) minor from the wide but narrower than the metalophid. The metalophid is wider than Benson LF of Arizona (Gidley, 1922; Gazin, 1942). The small gopher long, and enamel is present on the posterior surface. The lower molars from the Rexroad LF assigned to G. (N. ) minor by Hibbard (1967) are ellipsoidal on the occlusal surfaces, wider than long, and possess is smaller than both the holotype and Red Corral specimens. Larger enamel only on their posterior surfaces. The depth of the jaw below the samples from the Kansas, Texas, and Arizona faunas are needed, middle of the diastema in the four consecutively numbered dentaries however, to show the range of variation in the various populations. A is 5. 6, 4. 4, 4. 0 (est. ), and 5. 0, respectively. The labial jaw depth recent analysis of gopher evolutionary lineages in the Meade Basin of below p4 is 8. 8 in 4321 and 7. 5 (est. ) in 4322. Other measurements, southwestern Kansas is provided by Martin et al. (2011). Geomys minor including those of the type specimen of Nerterogeomys minor, are appears to have had a long biochronologic range in the Blancan. given in Table 5. A palate, 4325, containing the left and right P4 and M1, is Geomys sp. - large referred to Nerterogeomys. The protoloph (anteroloph) and metaloph Referred specimens. Pit C: 4326 (in part), isolated teeth. Pit D: (posteroloph) in P4 are equal in width and wider than long. Dentine 4033 (in part), isolated teeth. tracts have not yet developed. The reentrants are squared or U-shaped Description and remarks. Although most of the isolated gopher and filled with cementum, and there is no enamel on the posterior face teeth from the Red Corral LF are small and are most likely assignable of the metaloph. M1 is wider than long and possesses enamel on both to Nerterogeomys, some of the teeth are distinctly much larger than anterior and posterior surfaces separated by thin labial and lingual any previously reported for that subgenus. Eshelman (1975) noted dentine tracts. Measurements of the left teeth are: AP L of P4 = 1. 6, that gophers are unusual rodents in that the jaw and dentition increase width of metaloph of P4 = 1. 6; AP L of M1 = 1. 0, TW of M1 = 1. considerably in size with age; moreover, the degree of sexual variation 8. Palatal width across the P4s is 5. 0 and across the M1s is 5. 4. The is great. The presence of two distinct tooth sizes in the Red Corral LF prominent medial crest, which extends along the ventral midline of the does not appear to reflect age or sexual variation, however, but rather palate, becomes less pronounced anterior to P4 but remains distinct suggests the presence of two species because (1) there is a large and nearly to the anterior palatine (incisive) foramina. distinct size difference, (2) several large p4s and P4s belong to young In the collection are numerous isolated teeth of both adult and individuals as evidenced by uninterrupted enamel bands around the immature gophers from both Pit C and Pit D. The upper incisors are occlusal surface, and (3) there is a disproportionately smaller number bisulcate, as in Holocene Geomys. The average width of the metalophid of the large teeth, especially from Pit C. 20 TABLE 5. Measurements (in mm) of dentaries and teeth of Geomys TABLE 6. Statistical summary of jaw and tooth measurements (in mm) (Nerterogeomys) cf. minor from Red Corral Pit C compared with type of Prodipodomys idahoensis from Red Corral sites and Hagerman LF, specimen from Benson LF, Arizona. Idaho. V prefix = UMMP specimen.

4321 4324 USNM 10494 Red Corral Pit C Pit D Hagerman Measurement left 4322 left 4323 left right (type) p4-m3 6. 2 5. 5 Metric N OR Mean SD p4-m2 5 4. 6 4 5 Upper V50074 p4 length 2. 7 2. 4 2. 1 2. 7 P4-M1 (occlusal) occlusal 4 1.9-2.5 2. 19 0. 213 p4 width 2. 1 1. 9 1. 9 1. 9 1. 9 length m1 length 1. 1 1. 1 0. 9 1. 1 P4 length 7 0.9-1.2 1. 06 0. 105 1. 4 P4 anterior m1 width 2. 1 2 1. 8 2 2 7 0.4-0.7 0. 59 0. 099 m2 length 1. 1 1. 1 1 width P4 posterior m2 width 2 2 1. 7 7 1.1-1.5 1. 27 0. 138 1. 6 m3 length 1. 1 0. 9 width m3 width 1. 5 1. 5 M1 length 4 0.9-1.1 1 0. 071 incisor width 2. 2 2 1. 75 2 2. 1 M1 width 4 1.3-1.6 1. 45 0. 112 diastemal M2 length 1 0. 9 0. 9 0 length 7. 4 5. 6 5. 8 5. 6 5. 4 M2 width 1 1. 2 1. 2 0 diastemal width 3. 6 3. 2 2. 8 3. 5 3. 5 jaw depth Lower #4034 V50220 V50221 V52740 V53449 at p4 8. 8 c. 7. 5 p4-m1 occlusal 4 1.9-2.6 2. 23 0. 286 2. 4 In the collection from Pit C are a bisulcate upper incisor (width = length 3. 2) and two p4s in which the width of the posterolophid is 2. 5 and p4 length 9 0.9-1.25 1. 13 0. 108 1. 4 1. 3 1. 6 1. 4 2. 7. Among the teeth from Pit D are two large bisulcate upper incisors p4 anterior 9 0.9-1.2 1. 11 0. 107 1. 1 which are 3. 4 and 3. 6 wide. The average width of the metaloph of 10 width P4s is 2. 5 (2. 3-2. 7) and of the metalophid of 8 p4s is 2. 7 (2. 4-2. 9). p4 posterior 9 1.15-1.6 1. 39 0. 159 1. 3 1. 45 1. 4 1. 5 These teeth fall within the range of Geomys jacobi from the Rexroad width LF (Hibbard, 1967) and G. quinni from the Sand Draw LF of Nebraska (McGrew, 1944; Franzen, 1947; Skinner et al., 1972) and the Deer Park m1 length 4 0.9-1.2 1. 06 0. 119 1. 05 1 1. 05/1 LF from Kansas (Hibbard, 1956) but without skulls or mandibles with complete dentitions, specific identification is not possible. m1 width 4 1.2-1.5 1. 38 0. 13 1. 5 1. 6 1. 5/1. 5

Family Heteromyidae m2 length 1 1.1 1. 1 0 1 1 Prodipodomys cf. idahoensis Hibbard, 1962 Figures 19A-F m2 width 1 1.5 1. 5 0 1. 5 1. 6 Referred specimens. Pit C: 4327-4333, five right and two left approx. jaw 7 3.6-4.4 4. 04 0. 261 tooth-bearing maxillary fragments; 4334, edentulous left maxillary depth fragment; 4335-4344, five left and five right tooth-bearing partial diastema 7 3.4-4.6 3. 93 0. 42 dentaries; 4345, isolated cheek teeth; 4346, dp4; 4347, upper incisors. length Pit D: 4034, right dentary fragment with p4-m1; 4139, right dentary with m1; 4035, isolated teeth. Description. Nearly all of the dentaries and maxillaries are The cheek teeth are relatively hypsodont. Dentine tracts are fragmentary, and many from Pit C were concentrated in a small area of moderately to well-developed (0. 5-1. 5) in about 46 % (64 of 139) of the quarry, possibly as a result of owl predation. P4 and p4 are the most the isolated teeth from Pit C and in about half of the 10 teeth from Pit D. frequently preserved teeth, followed by M1 and m1 (Figs. 19A-F). M2 Of the 64 teeth, 46 show low wedge-shaped tracts less than 1. 00 high. and m2 are preserved in only one maxillary and dentary fragment (Fig. The other 18 teeth show higher, narrower tracts. Although dentine tracts 19C) respectively. M3 and m3 are missing from all specimens. The are measured from the base of the surrounding enamel (Zakrzewski, teeth vary in age from very young to old adults. 1981; Czaplewski, 1990), the true tract height of about half of the total The occlusal pattern of the teeth is basically like that of tooth sample cannot be accurately measured because either the teeth Prodipodomys centralis from Rexroad Locality 3 and the Wendell are broken or the teeth are old and worn such that the tract intersects Fox locality in Kansas and P. idahoensis from Hagerman, Idaho. The the occlusal surface. In general, the tracts are better developed on the lingual and labial reentrants separating the lophs (-ids) are shallower lingual sides of both upper and lower teeth and are somewhat better than those of P. centralis in comparable wear stages. The lingual cusp developed on the molars than on the premolars. Dentine tracts are not of P4 is smaller than the labial cusp and is directed more anteriorly. apparent on the teeth in most of the jaws and maxillaries. However, M1 and M2 have C-shaped patterns; the protoloph and metaloph are slightly developed tracts are present on M1 in 4328, on P4 and M1 in connected lingually and are separated labially by shallow reentrants. 4329 and on m1 in 4340 and 4034. In p4 of young individuals, there are two cusps on the protolophid and P4 and M1 have three well-developed roots. An exception occurs three cusps on the metalophid, the lophids are narrowly connected in a left M1 in which the two posterior roots are normal, and the large between deep labial and lingual reentrants, and there is a shallow anterior root is composed of two fused roots. In M2, the anterolabial anteromedian groove on the protolophid. With wear, the cusps and the root has partially or completely fused with the posterolingual root, groove disappear, and the reentrants quickly become shallow. The m1 opposite the small distinct posterolabial root. The alveolus of M3 and m2 are bilophodont and are lingually constricted. The alveolus shows that three roots have typically fused to one. of m3 is lingual to the incisor, the alveoli of the other teeth, and the The p4 is two-rooted, but the posterior root is broad and may be mandibular foramen. Tooth and alveolar measurements are given in composed of two fused roots. A single right p4 possesses, in addition, Table 6. The alveolar lengths of P4-M3 and P4-M2 in the maxillaries a tiny but distinct medial-lingual root resembling the small third root in from Pit C are shorter than those given by Zakrzewski (1970) for P. m1 of Sigmodon minor. The m1 is double-rooted but may show a fusion rexroadensis (synonym of P. centralis) from Rexroad Locality 3 (5. 40- of two smaller roots in both the anterior and posterior roots. In m2, the 5. 56 and 4. 56-4. 66 respectively) and are within the range of those of larger anterior root tends to fuse lingually with the posterior root; a thin the same species from the Wendell Fox locality (UM-K3-53) in Kansas shelf of bone in the alveolus separates the two roots labially in 4139. (5. 01-5. 35 and 4. 18-4. 85 respectively). The m3 alveolus, preserved only in a single jaw, 4139, from Pit D, is 21

FIGURE 19. Prodipodomys cf. idahoensis: A, right maxillary, P4-M1, 4328, Pit C; B, dp4, 4346, Pit C; C, right dentary fragment, p4-m1, 4034, Pit D; D, right dentary with incisor, p4-m1, 4340, Pit C; E, right dentary with incisor, adult p4 in dp4 alveolus, m1 alveolus, occlusal view, 4342, Pit C; F, right dentary with m1 and alveoli for p4, m2, and m3, 4139, Pit D. Perognathus cf. pearlettensis: G, right dentary with incisor, p4-m2, 4362, Pit C; H, left dentary, p4-m2, 4360, Pit C. Perognathus cf. gidleyi: I, right dentary with incisor, p4-m1, 4140, Pit D. 22 single-rooted. P. griggsorum, and P. minor from the early Blancan Benson LF of The Red Corral specimens have equally or slightly less developed Arizona, by its larger size, greater root reduction, and more hypsodont roots than Prodipodomys rexroadensis (Hibbard, 1954), which Skinner teeth with dentine tracts. P. idahoensis is the same size as P. centralis et al. (1972) synonymized with P. “Liomys” centralis (Hibbard, 1941b). but differs from it in having teeth that are more hypsodont with Root development in the holotype maxillary of “P. rexroadensis,” shallower reentrants and slightly less-developed roots and, possibly, in UMMP 29688, is comparable to that in the Red Corral maxillaries the absence of a shallow depression dorsal and labial to the mandibular except that the three roots in M2 are a little more distinct, although foramen. Unlike P. idahoensis, P. centralis is said to completely lack the anterolabial and lingual roots are slightly fused. The same is true dentine tracts, although Czaplewski (1990) interpreted emarginations for M2 in the partial skull of P. centralis from the Sand Draw LF of of enamel at the lateral bases of the tooth roots as broad, incipient Nebraska (Skinner et al., 1972). Hibbard (1962, p. 482) stated also that dentine tracts (see below). Comparisons between P. idahoensis and m3 of this species has two well-developed roots. P. tiheni remain obscure. Zakrzewski (1981) provided an emended Hibbard (1962, p. 482) and Zakrzewski (1969, p. 12) diagnosed diagnosis of P. tiheni stating that it “is distinguished from other species Prodipodomys idahoensis as being the size of P. rexroadensis (P. in the genus by being more hypsodont, having slightly higher dentine centralis) but having more hypsodont teeth with roots that are not as tracts, and a somewhat deeper masseteric fossa.” He also noted that well-developed. Since no maxillaries or upper molars of P. idahoensis “dentine tracts are absent or only slightly developed in Prodipodomys were reported, their statement about root development must be and seldom exceed 0. 7 mm in height whereas tracts in Dipodomys are limited to the lower teeth and a single left P4. Hibbard described the generally greater than 1. 0 mm and seldom are less than 0. 9 mm. ” alveolus of m2 in the holotype, USNM 22754, an adult, as deep and Tomida (1987, p. 70) noted a contradiction in that at least some teeth indicating the presence of a small labial root that had nearly completed of P. idahoensis actually have much higher dentine tracts than P. tiheni. coalescence with the large lingual root. Zakrzewski (1969) stated that Those of two isolated m1s of P. idahoensis are 1. 59 and 1. 38 in height the development of the roots of the teeth in this species is similar to that according to Zakrzewski (1969, p. 12) and are well within the range observed in Etadonomys tiheni from the latest Blancan Borchers LF of of Dipodomys hibbardi from 111 Ranch, Arizona. Czaplewski (1990) Kansas, which he later referred to the genus Prodipodomys. . According assigned to Prodipodomys idahoensis a sizeable sample of dentaries, to Hibbard (1943, p. 186), in the Borchers species, p4 and m1 have two maxillaries, and isolated teeth from the early Blancan Verde LF of roots while m2 and m3 are single-rooted. It appears from the available Arizona. He noted (p. 23) the presence of emarginations of enamel at the material that root development in adult specimens of P. idahoensis and lateral bases of the roots in some specimens of P. centralis illustrated by the Red Corral kangaroo rat is comparable. A series of maxillaries is Hibbard (Skinner et al., 1972) and interpreted these as broad, incipient needed to determine the extent of root reduction and fusion in M2. dentine tracts noting also that similar broad, rounded emarginations The mandibular foramen, preserved only in 4139, is dorsal and at the bases of roots in cheek teeth of P. tiheni were called dentine slightly lingual to the incisor (Fig. 19F). In Prodipodomys griggsorum tracts by Zakrzewski (1981). Czaplewski suggested that “perhaps the from the earliest Blancan Saw Rock Canyon LF of Kansas and in P. presumed differences in presence or absence of dentine tracts in some idahoensis the foramen is lingual to the incisor whereas, in P. kansensis Prodipodomys species are merely differences in authors’ perceptions from the Hemphillian Edson LF of Kansas, it is on the labial side or definitions of a dentine tract.” He illustrated a way of measuring (Zakrzewski, 1970). In 4139, the only Red Corral specimen in which the height of a dentine tract from the base of the enamel crown the posterior part of the dentary is preserved, there is no pit or fossa (Czaplewski, 1990, p. 19). More recently, Ruez (2009) noted that “of between the teeth and the ascending ramus as is found in most Holocene all of the species of the genus, P. idahoensis, especially the Hagerman, species of Dipodomys, and the shelf above the foramen is nearly level Idaho specimens, shows the greatest development of dentine tracts and with the alveolar ridge, as in P. griggsorum and P. idahoensis. In P. the greatest degree of hypsodonty.” Presumably, at first glance, it would centralis, a shallow depression occurs in this position whereas in the seem that P. idahoensis differs from P. tiheni in its smaller size, more two described dentaries of P. tiheni a pit or fossa occurs dorsal and poorly developed roots, better developed dentine tracts, the absence of labial to the mandibular foramen (Zakrzewski, 1981, p. 79). In most a temporal pit or fossa dorsolabial to the mandibular foramen, and the Holocene specimens of Dipodomys, the mandibular foramen is typically more lingual placement of the m3 alveolus with respect to the foramen. located in a pit labial to the incisor, although in some specimens the pit However, it would appear that dentine tract height and the development lies dorsal and labial to the foramen or is absent altogether. Zakrzewski of a temporal pit or fossa are quite variable within and between species (1981), noting the variability of the relationship of foramen to fossa of both Prodipodomys and Dipodomys. Unfortunately, sample size from in both Prodipodomys and Dipodomys, considered this feature to be the type localities of both P. idahoensis and P. tiheni is quite small. The unreliable as a taxonomic character at the generic level. former is represented by four dentary fragments and three isolated teeth The capsular process for the base of the incisor in 4139 is on from the Hagerman LF of Idaho and the latter by two dentaries from the the labial side of the jaw 2. 0 posterior to the anterior border of the Borchers LF of Kansas. No maxillaries have been reported. mandibular foramen. The masseteric ridge in some specimens from Pit Albright (1999) assigned to Prodipodomys idahoensis a significant C ends in a pronounced knob that extends above the ventral surface of sample of specimens from the San Timoteo Badlands in California, the diastema as in Prodipodomys centralis, whereas in other specimens and the species has been recognized in other Blancan faunas as well. from both Pits C and D, the knob is less pronounced and more ventral, Kangaroo rat specimens from Wolf Ranch, Arizona, were referred by a characteristic which Skinner et al. (1972) used to distinguish P. Harrison (1978) to P. idahoensis; however, they have higher, narrower idahoensis from P. centralis but which appears to vary intraspecifically. dentine tracts and a greater amount of root fusion. Tomida (1987) and Jaw and tooth measurements of the Red Corral specimens and those Czaplewski (1990) suggested that they might represent a more advanced from Hagerman are summarized in Table 6. kangaroo rat such as Dipodomys hibbardi. Recently, both identifications Remarks. The distinction between Dipodomys and its presumed were considered correct because both taxa were recognized from Wolf ancestor Prodipodomys was clarified by Zakrzewski (1981) who Ranch (Albright, 1999; Ruez, 2009). Mou (2011b) recognized a small emended the diagnosis of both genera based primarily on crown height and a large species of Prodipodomys in the early Blancan Panaca LF of of the teeth rather than root loss. He observed that the crown height in Nevada. The smaller species was assigned to P. minor Gidley because adults of Dipodomys generally exceeds the length of the root, whereas of its small size and the fusion of roots in both upper and lower cheek the crown height in adults of Prodipodomys is approximately the teeth. Incipient dentine tracts were noted on the sides of p4. Mou same as the root length. The root in Dipodomys is generally a tubular assigned the larger species to P. tiheni and noted that the cheek teeth are continuum of the crown. The molars of Dipodomys are single-rooted in significantly larger and slightly higher crowned than those of P. minor advanced species whereas primitive species may possess molars with and that they possess low dentine tracts. Mou compared P. tiheni with P. more than one root but they are generally fused rather than independent. centralis of similar size but made no comparisons between P. tiheni and The p4 is two-rooted and P4 three-rooted in primitive species whereas P. idahoensis. Dalquest et al. (1992) commented that it is still unclear in advanced species, the premolars become single-rooted through how species of Prodipodomys are related to each other or to species fusion. Zakrzewski (1981) noted that in Prodipodomys evidence for two of Dipodomys. Pending the discovery of additional fossils and/or a or more roots is easily observable on each of the teeth. In Dipodomys, revision of the genus Prodipodomys, I tentatively refer the Red Corral dentine tracts are well-developed whereas in Prodipodomys dentine kangaroo rat to P. idahoensis. tracts are absent or only slightly developed. In Prodipodomys, a distinct anterocone is generally present on P4 whereas in Dipodomys the Perognathus cf. gidleyi Hibbard, 1941b, c anterocone is lost early with wear. Figure 19I Prodipodomys idahoensis is distinguished from P. kansensis, Referred specimens. Pit C: 4348-4358, six left and five right 23 TABLE 7. Statistical summary of jaw and tooth measurements (in m3 are lacking. mm) of Perognathus from Red Corral and other Blancan local faunas. The Red Corral specimens were compared with the holotype and topotypes of Perognathus gidleyi from Rexroad Locality 3 (Hibbard, Measurement N OR Mean SD 1941b, c ) and additional material from the Borchers LF (Hibbard, R.C. Perognathus cf. gidleyi Red Corral Pit C Rexroad 1941a) as well as with a series of P. rexroadensis jaws from the Fox Pit D Canyon LF (Hibbard, 1950). They most closely resemble P. gidleyi in KU 4775 #4140 the dimensions of the teeth and in the pattern of p4, although the jaws type are about 7 % shallower and the diastema is about 20 % shorter (Table p4 length 8 0.75-0.9 0.82 0.053 0.7 0.8 7). p4 width 8 0.75-0.9 0.84 0.058 0.85 0.8 The metalophid of p4 is distinctly wider than the hypolophid m1 length 5 1.0-1.15 1.04 0.065 1 1.1 (= protolophid), and the posterior cusps are larger and more widely m1 width 5 1.1-1.2 1.14 0.042 1.05 1.15 separated from each other than the anterior cusps. The anteromedian p4-m1 length 4 1.85-1.95 1.88 0.05 1.7 1.85 groove is only slightly developed. The labial and lingual reentrants lingual jaw depth 8 2.5-2.7 2.55 0.076 2.7 2.5 are about equally deep, but the lingual one may be wider, resulting below p4 in a central union of the metalophid and the hypolophid. The m1 is labial jaw depth 9 2.7-3.1 2.94 0.124 3 2.9 bilophodont, and the labial stylids are weakly developed compared below p4 to the lingual and medial cusps. The teeth vary from young to mature diastema length 6 2.9-3.2 3 0.11 3 adult. min. diastema The masseteric ridge slopes at about a 35 degree angle and does 10 0.8-1.1 0.94 0.084 1.1 1 width not extend to the top of the diastema. The mental foramen is below or Perognathus. rexroadensis Fox Canyon slightly ahead of the anterior extremity of the ridge. p4 length 3 0.8-0.9 0.87 0.058 Tooth and jaw measurements of Perognathus gidleyi and P. p4 width 9 0.8-1.0 0.89 0.054 rexroadensis are summarized in Table 7. P. rexroadensis is larger than m1 length 3 1.1-1.2 1.15 0.05 P. gidleyi. The jaw is about 20 % deeper, the diastema is about 13 m1 width 9 1.0-1.3 1.2 0.085 % longer, and the tooth row is about 8 to 10 % longer. The p4 of P. p4-m1 length 3 1.9-2.1 2.02 0.104 rexroadensis differs from that of P. gidleyi in that the lingual reentrant valley is deeper than the labial valley, resulting in a more labial lingual jaw depth 6 3.1-3.7 3.22 0.238 connection of the metalophid and the hypolophid. P. mclaughlini from below p4 the Saw Rock Canyon LF is the size of P. gidleyi but the p4 pattern is labial jaw depth 3 3.7-3.9 3.8 0.1 like that of P. rexroadensis in having the deeper lingual reentrant valley. below p4 P. maldei is about the size of P. gidleyi but reportedly possesses a well- diastema length 3 3.8-4.2 4 0.2 developed hypostylid on p4. P. pearlettensis, P. henryredfieldi, and P. min. diastema dunklei are smaller species. P. strigipredus from the early Blancan Verde 3 1.3 1.3 0 width LF of Arizona has a relatively wider metalophid on the p4 that is nearly Measurement N OR Mean SD as wide as the hypolophid, deeper labial and lingual reentrants on p4, Perognathus cf. pearlettensis Red Corral Pit C and m1 that is anteroposteriorly compressed and higher crowned. The p4 length 6 0.55-0.6 0.58 0.027 reader is referred to Czaplewski (1990) and Mou (2011b) for further p4 width 6 0.55-0.6 0.59 0.02 comparisons among fossil species. m1 length 4 0.75-0.9 0.85 0.071 Remarks. Pocket mice are frequent targets for predation by owls, m1 width 4 0.75-0.9 0.86 0.075 and this may account for the local abundance of these forms in the p4-m1 length 4 1.35-1.5 1.43 0.065 fauna although no fossilized pellets were found. The larger species, m2 length 3 0.65-0.8 0.73 0.076 Perognathus cf. gidleyi, is slightly more abundant than the smaller m2 width 3 0.75-0.9 0.85 0.087 species, P. cf. pearlettensis. lingual jaw depth 4 1.7-2.3 2 0.245 Perognathus cf. pearlettensis Hibbard, 1941a below p4 Figures 19G-H labial jaw depth 4 2.0-2.5 2.3 0.216 below p4 Referred specimens. Pit C: 4360-4367, two left and six right dentaries and dentary fragments; 4368, much worn lower left dentition diastema length 3 2.0-2.7 2.3 0.361 lacking m3; 4369, right maxillary with P4-M1. min. diastema 4 0.6-0.9 0.79 0.131 Description. As with the larger species described above, this width small pocket mouse is represented by a series of partial dentaries or Perognathus pearlettensis Borchers LF. dentary fragments (Figs. 19G-H), most of which came from a small p4 length 5 0.65-0.75 0.69 0.042 area of Pit C. Most are bleached and some are fractured. The jaws are p4 width 4 0.6-0.7 0.66 0.048 broken posterior to p4, m1, or m2. The absence of m3s can be explained m1 length 2 0.95 0.95 0 by several factors, including their small size and loss during digestive, m1 width 2 0.95-1.0 0.98 0.035 taphonomic, and screen washing processes. p4-m1 length 2 1.5-1.65 1.58 0.106 The jaws and teeth were compared with paratypes of Perognathus m2 length 3 0.8-0.9 0.87 0.058 pearlettensis from the Borchers LF (Hibbard, 1941a) and other m2 width 3 0.9-1.0 0.97 0.058 lingual jaw depth specimens from Fox Canyon (Hibbard, 1950) and they show no 3 2.0-2.4 2.2 0.2 significant differences except their slightly smaller size. The pattern below p4 of p4 is like that of P. pearlettensis. The tooth is sub-quadrate with labial jaw depth 5 2.5-2.8 2.64 0.152 the four well-developed cusps separated in younger teeth by deep, below p4 vertical valleys. In one specimen, 4361, there is a very low medial cusp diastema length 1 2.1 2.1 0 on the metalophid. In occlusal view, the anterior, labial, and lingual min. diastema reentrant valleys appear shallow; the lingual reentrant is slightly 3 0.9 0.9 0 wider and deeper than the labial reentrant thus giving the protoconid- width hypoconid connection a more labial position as seen in P. pearlettensis. tooth-bearing partial dentaries; 4359, left P4, left M1. Pit D: 4140, right With further wear, the cusps will present an X-pattern. The m1 and m2 dentary with incisor, p4-m1; 4141, right dentary fragment with p4. are bilophodont. The labial stylids are less developed than the lingual Description. A medium-sized pocket mouse is represented by a cusps, and the hypostylid of m2 is especially weak. The tooth roots are series of partial dentaries, most of which came from a very small area of not exposed. Pit C and may have been concentrated there by owl predation although The masseteric crest extends at about a 45 degree angle to the no fossil owl pellets were found. Nearly all of the dentaries are broken top of the diastema and terminates ventrolateral to the posterior part of posterior to p4 or m1 (Fig. 19I) and some are bleached and fractured. the diastema. The mental foramen is ventral to the anterior extremity The p4 is the most frequently preserved tooth followed by m1; m2 and of this ridge, as in Perognathus pearlettensis. None of the dentaries is complete enough to show any features of the posterior region. 24

FIGURE 20. Peromyscus sp. (large): A, right dentary with incisor, m1-m2, 4145, Pit D; B, right dentary, m1-m2, 4039, Pit D. Reithrodontomys cf. rexroadensis: C, right dentary with incisor, m1-m2, 4393, Pit C. Onychomys cf. pedroensis: D,left M1, 4402, Pit C. Bensonomys cf. arizonae: E, right dentary with incisor, m1-m3, 4037, Pit D; F, left dentary, m1-m2, 4143, Pit D.

Measurements of jaws and teeth from Red Corral Pit C and (Zakrzewski, 1969), Wolf Ranch (Harrison, 1978), Verde (Czaplewski, Borchers (type locality) are summarized in Table 7. Measurements of 1990), Blanco (Dalquest, 1975), White Rock (Eshelman, 1975), specimens from Fox Canyon are not given, although the Fox Canyon and Borchers (Hibbard, 1941a, 1942) local faunas. Dalquest (1978) and Borchers specimens are nearly identical in size. The Red Corral reported three distinctly different-sized species from the Beck Ranch specimens average 12 % shorter tooth row, 12 % shallower jaw depth, 8 LF of Texas. % shallower diastema, and 17 % narrower incisor. There is virtually no Most authors have assigned, at least tentatively, the small species overlap in size ranges between the Red Corral and Borchers samples, of pocket mouse from Blancan faunas in the Great Plains and Arizona although in several measurements the largest values for Red Corral to Perognathus pearlettensis because of a general similarity in size equal the smallest for Borchers. and dental characteristics, and I have followed that practice for the Remarks. The joint occurrence of at least two species of Red Corral specimens. Because these specimens are smaller than those Perognathus in a fauna is common. Two forms, one large and one from either Fox Canyon or Borchers, it is entirely possible that another small, are recognized from the Fox Canyon (Hibbard, 1950), Hagerman species is represented in the fauna. However, in the absence of other 25 detectable significant differences, I am reluctant to establish anew labial jaw depth below m1 is 3. 3. species on the basis of size alone. A right m1, 4389, of a young adult resembles the others in possessing Dalquest (1975) observed that specimens from the Blanco LF a broad, bluntly rounded, anteromedially notched anteroconid. A poor referred to Perognathus pearlettensis were a trifle smaller than the ectocingulum and a weak mesocingulum are present. The tooth is 1. 6 topotypes with which they were compared. He noted that teeth and long and 1. 05 wide. jaws of Perognathus offer few characters, other than actual and relative No upper teeth or maxillaries are present in the sample from either size of teeth that are diagnostic at the specific level. Pocket mice are Pit C or D. common mammals of the arid plains and deserts of the Southwest today, Remarks. Six species of Peromyscus have been reported from and several species often occur together. Unfortunately, morphological Blancan faunas in the Great Plains. Two of these, P. sawrockensis differences between extant species, particularly the smaller species and P. beckensis, were later referred to the genus Symmetrodontomys such as P. flavus, P. flavescens, and P. merriami, and even between – the former by Martin (2000) and the latter by Dalquest (1980). the extant genera Perognathus and Chaetodipus, may not be apparent The remaining four include two large species: P. kansasensis and in teeth and jaws making assignment to species and even to genus P. hagermanensis and two smaller species: P. baumgartneri and P. problematical. In view of this, the small Blancan pocket mice may cragini. The large Peromyscus specimens from Red Corral were well represent more than one species. Better fossil material and greater compared with the holotype of P. kansasensis from Rexroad Locality resolution of age differences in Blancan faunas are necessary before 3, Meade County, Kansas, and with published descriptions of P. this can be feasibly determined. hagermanensis from the Blancan Hagerman LF of Idaho. The holotype of P. kansasensis is a right dentary, KU 4597, described by Hibbard Family Cricetidae (1941b, c). The incisor and m1-m3 are present. The teeth are large and Subfamily Cricetinae uncrowded with low cusps and wide valleys between the cusps. There Peromyscus sp. - large are no lophids or stylids. The m1 is longer and narrower than that of Figures 20A-B the Red Corral specimens and appears to lack an anteromedial notch Referred specimens. Pit C: 4388, right dentary fragment with m2; on the anteroconid. Measurements of the holotype are: m1-m3 = 4. 1, 4389, right m1. Pit D: 4039, right dentary fragment with m1-m2; 4040, m1 = 1. 65 long and 1. 05 wide; m2 = 1. 35 long and 1. 05 wide; m3 = left dentary fragment with m1; 4145, right dentary with incisor, m1-m2. 1. 1 long and 0. 9 wide; diastema = 3. 0 long and 1. 1 wide (minimal); Description. Remains of Peromyscus are relatively rare in the labial jaw depth below m1 = 3. 0. No other specimens from the type Red Corral LF and in Blancan faunas in general. The most complete locality are known. specimen from the Red Corral LF, 4145 (Fig. 20A), is that of a large More recently, Skinner et al. (1972) referred to this species a deer mouse the size of the Holocene Peromyscus leucopus. The jaw is maxillary from the Sand Draw LF of Brown County, Nebraska, and that of a fairly young adult and is broken across the alveolus of m3. The Dalquest (1978) referred a series of dentaries from the Beck Ranch LF occlusal length of m1-m2 is 2. 95. The m1 is subrectangular in occlusal of Scurry County, Texas. Dalquest (1978) stated that the Beck Ranch outline. The anteroconid is moderately broad, bluntly rounded and is jaws have teeth a bit smaller than those from Kansas, but that no other slightly divided by an anteromedial notch or flexid. The metaconid is difference can be detected. He gave no measurements and I have not separated from the anteroconid by a deep, narrow anterointernal valley. had an opportunity to examine these specimens which may or may not The remaining valleys and folds are deep and V-shaped. A prominent, belong to this species. The Red Corral jaws do not closely resemble the slightly serrated ectocingulum connects the protoconid and hypoconid. holotype of Peromyscus kansasensis and, in the absence of topotypes, A prominent mesocingulum connecting the metaconid and entoconid that could give the range of variation, I cannot justify assigning the is raised to form a small mesostylid. The posterior cingulum is well- large Red Corral mouse to this species. developed. The m1 is 1. 6 long and 1. 1 wide. The m2 is rectangular Peromyscus hagermanensis was originally described from the shaped. Small cingula are present in both labial and lingual valleys. Hagerman LF in Idaho by Hibbard (1962). Additional specimens were The posterior cingulum is wide. The tooth is 1. 35 long and 1. 1 wide. described by Zakrzewski (1969), and the Idaho material is represented by The diastema is 3. 3 long and 1. 15 wide (minimum). The width of the several parts of dentaries and maxillaries, all of which are probably too incisor is 0. 6. The dorsal and ventral ridges of the masseteric crest are fragmentary for adequate comparison. The teeth show variation in the sharply defined and terminate in a prominent ridge below the anterior development of accessory lophs (-ids) and styles (-ids), which Hooper root of m1. The mental foramen is 0. 3 anterior to and 0. 5 below this (1957) has shown to be common in the genus. A slight anteromedial ridge. The labial jaw depth below m1 is 3. 6. notch is present on at least one of the m1s. It is possible that more A right dentary fragment, 4039 (Fig. 20B) is that of a young adult than one species is present in the Hagerman LF, although Zakrzewski, and is similar to 4145. It is broken across the diastema and posterior to recognizing the small sample size and the possible variation in dental m2. The incisor and ventral portion are missing. The occlusal length of characters, preferred to treat the Hagerman sample as one species. m1-m2 is 3. 05. The m1 is subrectangular. The anteroconid is broad and Another large species of Peromyscus (P. nosher) has been described bluntly rounded but is not divided anteromedially. The anterolophid from the early Blancan White Bluffs LF of Washington (Gustafson, is separated from the anteroconid by a slight indentation. The 1978). It is similar in size and morphology to P. hagermanensis but anterointernal valley between the anteroconid and the metaconid is not supposedly differs in having a more distinctly bilobed anteroconid on as narrow as in 4145. An ectostylid and a mesostylid are present. The m1. posterior cingulum is wide and connects with the entoconid to enclose In recent years, several workers have assigned larger specimens a small pit. The m1 is 1. 7 long and 1. 1 wide. The m2 is rectangular of Peromyscus to P. hagermanensis as a default species for want of and possesses a prominent anterolophid, a good mesostylid, and a weak other large species for comparison. Czaplewski (1987b) referred ectocingulum. The posterior cingulum is less developed than in 4145 an upper left M1 from the Clarkdale LF in the Verde Formation of and is weakly joined to the entoconid. The m2 is 1. 35 long and 1. 1 Arizona. Tomida (1987) referred a series of teeth from the Blancan wide. The mental foramen is situated near the top of the labial surface Duncan and 111 Ranch local faunas from Arizona to this species. about 1. 0 ahead of the masseteric crest, which is not as prominent as He reported a considerable range of variation in tooth dimensions in 4145. but noted that the teeth were somewhat smaller than the teeth from A left dentary fragment, 4040, is that of a mature adult. The Idaho, that many of them possessed stylids, and that the anteroconid ventral and posterior portions are missing. The only tooth present is on m1 was either unicuspid or weakly bilobate. Martin et al. (2002b) m1, which resembles that in the other jaws. The anteroconid is broad originally referred several molars from the Deer Park B LF of Meade and bluntly rounded and very slightly notched anteromedially. The County, Kansas, to this species, noting that the teeth were the same anterolophid is not distinct from the anteroconid. A small ectocingulum size or smaller than those of the Idaho species. Mou (2011a) also and mesocingulum are present. The m1 is 1. 65 long and 1. 1 wide. assigned to P. hagermanensis a fairly large sample of upper and lower The alveolar length of m1-m3 is 4. 0. The diastema is 3. 0 long and 1. molars, maxillary fragments, and dentaries from the early Blancan 0 wide. The mental foramen is 0. 7 anterior to and slightly below the Panaca LF of Nevada and also reported a considerable range in tooth masseteric crest which resembles that in 4039. dimensions although, overall, the teeth were similar in size to those A right dentary fragment with m2 and part of the incisor, 4388, is from Arizona. Mou also noted that the m1s varied somewhat in shape that of an old adult. It is broken across the alveolus of m1, but a portion and cusp alignment and that the anteroconid was either unicuspid or of the ascending ramus is preserved. The occlusal surface of m2 is worn weakly bilobate. There was also variation in the presence or absence nearly flat and is 1. 3 long and 1. 0 wide. Weak labial and lingual cingula of styles (-ids) and lophs(-ids). If all of these assignments are correct, are present. A shallow sulcus is present above the capsular process. The P. hagermanensis would have had a large geographic range from Idaho 26 to the Texas Panhandle and to Arizona, which seems very unlikely. R. structures and the degree to which they are developed is highly variable A. Martin (written communication, 2015) commented that the features in species of the genus Peromyscus. used to identify P. hagermanensis are so generalized they could refer to Some of the smaller teeth from the Red Corral localities resemble almost any ancestral Peromyscus species. He expressed the opinion that the type of Peromyscus baumgartneri in size, absence of accessory the assignment of any Great Plains Peromyscus to P. hagermanensis cusps, and absence of an anteromedial notch on the anteroconid. is probably incorrect and that he and his co-workers no longer refer The holotype of P. baumgartneri is from Rexroad Locality 3, and Meade Basin mice to that species. For these reasons, a specific name the paratypes are from the older Fox Canyon LF. It is possible that is not applied to the Red Corral specimens at this time. Clearly, the some of the Red Corral specimens also belong to this species, but genus is in need of revision considering the large number of fossil and until the geologic range and the range of morphologic variation of P. extant species that have been described (30 in just the United States baumgartneri is better known, I hesitate to assign such fragmentary alone according to one count). Such a revision is beyond the scope of material to this species. this paper. Martin (written communication, 2015) suggested that any Another smaller species, Peromyscus cragini, has been reported such revision should involve first a general sorting to size followed by from the late Blancan White Rock LF of northcentral Kansas a consideration of the shape of m1 and the width of reentrant valleys, (Eshelman, 1975). The dentary from this locality is similar to the the width and symmetry of the anterocone on M1 and the anteroconid holotype of P. cragini from the Irvingtonian age Cudahy LF of Meade on m1, and the development of the labial cingulum. Least important County, Kansas, and to the holotype of P. baumgartneri as well. The would be the development of accessory structures (stylids, lophids, White Rock dentary has a slightly larger mental foramen than that of etc.) and whether the anteroconid is bifid or not as these features have the type. The diastemal width is proportionately greater than that of been shown to be variable even within a species. P. baumgartneri and more like the condition found in P. cragini. The White Rock dentary has a small anterior groove on the face of m1 and Peromyscus spp. – small there are no accessory cusps or stylids. Referred specimens. Pit C: 4390, edentulous right dentary fragment; 4391, right m1; 4392, right dentary with incisor, m1-m2. Pit Reithrodontomys cf. rexroadensis Hibbard, 1952a D: 4041, left dentary fragment with m1; 4042, right dentary with m2; Figure 20C 4043, two right m1s and a right M1. Referred specimens. Pit C: 4393, right dentary with incisor, m1- Description. At least two small deer mice are represented by m2; 4394, right dentary with incisor, m1-m2; 4395, right dentary with material too fragmentary to permit species determination. A left dentary m1-m3; 4396, left dentary fragment with m1; 4397, right maxillary fragment, 4041, is that of a mature adult. It is broken just anterior to fragment with M1. the mental foramen and posterior to m1. The m1 is 1. 5 long and 1. 0 Description. The right dentary, 4393, is that of a young adult wide and narrows anteriorly, giving the tooth a triangular appearance. of a small species of harvest mouse (Fig. 20C). It lacks m3 and the The anteroconid is narrow and is not divided anteromedially. Valleys coronoid, articular, and angular processes. Incisor width is 0. 45. The between the cusps are V-shaped and no cingula or stylids are present. The anteroconid of m1 is narrower than in Reithrodontomys megalotis m1 is slightly larger than that of the type of Peromyscus baumgartneri (Baird) or R. montanus (Baird) and more pointed than in Baiomys. The Hibbard from Rexroad Locality 3 (Hibbard, 1954). The mental foramen anterolophid is a short cingulum joining the front of the protoconid. The is high on the labial surface of the jaw and 1. 0 in front of the anterior anterointernal valley is deep, but the metaconid is not pressed against end of the masseteric crest. the anteroconid. The posteroexternal valley (major fold) between the Two right m1s, 4043a and 4043b, belong to a young and an old protoconid and the hypoconid is broad, and there is a low cingulum adult, respectively, and resemble that in 4041 but are slightly larger but no ectostylid. No mesostylid is present in the deep valley between (both are 1. 55 long and 1. 05 wide) and have a slightly broader and the metaconid and the entoconid. The posterior cingulum is well- more rounded anteroconid. All three m1s are broader posteriorly and developed. The m1 is 1. 3 long and 0. 8 wide. The anterolophid on m2 is more triangular in shape than those of Peromyscus cragini from the not well-developed, and there is no pit between it and the protoconid. A Cudahy Fauna of Kansas (Hibbard, 1944; Paulson, 1961). Another slightly raised cingulum occurs in the major fold. The tooth is narrower right m1, 4391, of a young adult is narrower and more rectangular than posteriorly, and the posterior cingulum is poorly developed. The m2 is either of the other m1s. The anteroconid is broad, bluntly rounded, 1. 0 long and 0. 85 wide. The alveolus of m3 is 0. 5 long and 2-rooted. and slightly notched anteromedially. The valleys are deep and slightly The alveolar length of m1-m3 is 2. 90. The occlusal length of m1-m2 is broader. A weak ectocingulum and mesocingulum are present. The 2. 3. The anterior end of the diastema is broken; the minimum diastemal tooth is 1. 5 long and 0. 95 wide. width is 0. 7. The mental foramen is large and dorsolabial in position A right dentary, 4392, of an old adult is broken just anterior to but lingual to m1. The masseteric crest is very weak and terminates the mental foramen but contains the incisor, m1-m2, m3 alveolus, and behind the anterior root of m1, in contrast with R. megalotis and R. the lower part of the ascending ramus. The teeth are heavily worn and montanus in which the masseteric crest terminates below or ahead of show no pattern. The occlusal length of m1-m2 is 2. 55, and the alveolar the anterior root of m1. The pterygoid fossa is shallow and broad. The length of m1-m3 is 3. 4. Width of the incisor is 0. 7, and the labial jaw capsular process for the base of the incisor is not as pronounced as it is depth below m1 is 3. 5. A shallow sulcus is present above the capsular in Baiomys, and there is no groove above it. process. In the edentulous right dentary fragment, 4390, the alveolar A right dentary, 4394, is that of a more mature adult and is broken length of m1-m3 is 3. 5. behind m2. The incisor width is 0. 5. The m1 and m2 resemble those A right M1, 4043c, is 1. 6 long, 1. 0 wide and possesses a small in 4393 except that the anteroconid of m1 is slightly broader and mesostyle. It probably belongs to the same species as the lower teeth. the anterointernal valley is not as deep. No stylids are present. The A second small species of Peromyscus is represented by a right anterolophid on m2 is poorly developed. The m1 is 1. 25 long and 0. 85 dentary, 4042, containing the incisor, m2 and the two-rooted alveoli for wide and m2 is 1. 05 long and 0. 85 wide. The diastema is 2. 0 long and m1 and m3. The jaw is broken behind the m3 alveolus. The alveolar 0. 8 wide, and the mental foramen is like that in 4393. The masseteric length of m1-m3 is 3. 2. The m2 lacks stylids and is 1. 05 long and 0. 9 crest is weak and terminates below the anterior root of m1. The labial wide and is slightly smaller than m2 in the type of P. baumgartneri, with depth of the jaw below m1 is 2. 4. which it was compared. It is about the size of m2 in Reithrodontomys A right dentary, 4395, of a young adult is broken across the diastema wetmorei and Reithrodontomys rexroadensis from the Fox Canyon LF and behind m3. A portion of the incisor and m1-m3 are present. The (Hibbard, 1952a) but is slightly shorter and wider. The late Claude W. incisor width below m1 is 0. 5. The jaw resembles Reithrodontomys Hibbard examined the specimen and considered it to represent a small in most respects but shows some similarities to Baiomys, the pygmy species of Peromyscus. It is larger than Baiomys kolbi from the Fox mice. The anteroconid of m1 is slightly more rounded anteriorly as in Canyon LF (Hibbard, 1954). The width of the incisor is 0. 5 and that Baiomys and not as pointed as in R. montanus, but the distance across of the diastema (minimum) is 0. 9. The mental foramen is situated high the protoconid-metaconid is narrower than in Baiomys kolbi from the on the labial side of the jaw just in front of the anterior root of m1. The Fox Canyon LF (Hibbard, 1952a). The anterointernal valley is shallow. labial jaw depth below m1 is 2. 4. A small mesostylid is present on m1 and an ectostylid is present on m1 Remarks. As noted above, remains of Peromyscus are rare in and m2. The anterolophid of m2 is slightly better developed, as in some Blancan faunas. Known fossil species have been described from R. montanus, but there is no pit between it and the protoconid as there is relatively few specimens and most have been assigned to the subgenus in R. megalotis. The narrowness of the teeth, especially m2, resembles Haplomylomys based on the absence of stylids and lophids. Hooper Reithrodontomys rather than Baiomys, in which m2 is more square. The (1957), however, showed that the presence or absence of accessory posterior cingulum is well-developed in both m1 and m2. The m3 is 27 triangular in outline, and the enamel wear pattern is S-shaped. The tooth It also should be noted that Tomida (1987, p. 88) assigned a is more reduced than in R. fulvescens but not as much as in R. megalotis larger sample of teeth and jaw fragments from the early Blancan or R. montanus. The anterolophid is narrow. The protoconid is well- Duncan and late Blancan111 Ranch local faunas of southern Arizona developed and is separated from the metaconid by a shallow valley. The to Reithrodontomys rexroadensis. His hypodigm includes upper teeth, metaconid is shorter than in B. kolbi. The hypoconid is better developed although Hibbard (1952a) was reluctant to assign upper teeth to the than in either R. megalotis or R. montanus. The major fold is slightly species with any degree of confidence. A single M3 from the Duncan longer than in either species but not as long as in R. fulvescens and section shows an occlusal enamel pattern that is transitional between extends nearly half way across the tooth. The primary fold is narrow, E-shaped and C-shaped (Hooper, 1952, p. 28). The three m3s show and the hypoconid and entoconid are fused. Measurements of the teeth an enamel wear pattern that is S-shaped (Hooper, 1952, p. 29). These in 4395 are: occlusal length of m1-m3 = 2. 95; occlusal length of m1- and certain other characters indicate, according to Tomida, that R. m2 = 2. 25; m1 = 1. 25 long by 0. 8 wide; m2 = 1. 0 long by 0. 8 wide; rexroadensis is transitional between the R. megalotis species group and m3 = 0. 7 long by 0. 65 wide. The masseteric crest terminates ahead of the R. fulvescens species group of Hooper (1952), although Martin et the anterior root of m1 as in some R. montanus. The mental foramen is al. (2003) consider the S-shaped morphology of m3 to be underived large and more labial than in the other specimens although, according to and of little value for higher taxonomic differentiation. If Tomida is the late Claude W. Hibbard, this is somewhat variable in Baiomys. The correct in his assignment of the Arizona fossils to R. rexroadensis, the labial jaw depth below m1 is 2. 3. geographic range of the species (= R. wetmorei according to Martin) is A left dentary fragment, 4396, of a young adult is broken behind extended to west of the Rocky Mountains and the geologic age from m1. The m1 resembles that in 4393 in having a narrow pointed the early Blancan to the late Blancan (Tomida, 1987, p. 91). Tomida anteroconid and in lacking stylids. It is 1. 2 long and 0. 8 wide. The (1987, p. 92) also described a new species, R. galushai, from higher in incisor is missing; minimum diastema width is 0. 7. The masseteric the 111 Ranch section (late Blancan). He characterized it as being very crest terminates below the anterior root of m1. similar to R. rexroadensis in size and general tooth morphology but In the collection is a right maxillary fragment, 4397, of an adult differing from it in having m1 with a distinctly or indistinctly bilobed bearing only the M1, which is 1. 45 long and 0. 9 wide. The anterocone anteroconid and slightly narrower molars relative to the width but is rounded and not bi-lobate. The paracone and protocone are alternating with a more rounded, conical metaconid and entoconid on m1 and m2. but the metacone lies opposite the hypocone. A weak anterolabial According to Tomida (1987, p. 39, table 23) the mean length of m1 in cingulum is present, and a small fourth root occurs medially on the R. galushai (1. 36) is slightly greater than that of the Arizona sample of labial side as in Reithrodontomys megalotis and R. montanus. The lower R. rexroadensis (1. 29) and the single m3 of R. galushai matches in size m1s of these species sometimes possess a small third root. Additional the larger of the m3s of R. rexroadensis. I have not had an opportunity roots were not observed in the lower jaws from Red Corral. to examine any of Tomida’s specimens but the size of the Red Corral Remarks. Remains of Reithrodontomys are rare in Blancan molars falls within or close to the values given by Tomida for both faunas. Four species have been described: R. wetmorei, R. rexroadensis, species. The fourth Blancan species of Reithrodontomys, R. pratincola, R. galushai, and R. pratincola. R. wetmorei and R. rexroadensis were described by Hibbard (1952a) from the early Blancan Fox Canyon LF of Meade County, Kansas. Their dentitions are generalized in TABLE 8. Statistical summary of tooth measurements (in mm) of comparison with recent forms, and their relationship to living species Onychomys cf. pedroensis from Red Corral Pits C and D. Abbreviations: is uncertain. Some authors have suggested that the two species may L = length; Wtri = width of trigonid; Wtal = width of talonid. be conspecific (Martin et al., 2003). Martin (written communication, 2015) expressed the opinion that R. rexroadensis (and Baiomys kolbi) Red Corral Pit C are synonymous with R. wetmorei. As defined by Hibbard (1952a), R. Tooth Metric N OR Mean SD Tooth Metric N OR Mean SD 1. 85-2. wetmorei is the larger of the two species and is characterized by a wider m1 L 9 1. 94 0. 058 M1 L 11 2. 0-2. 2 2. 09 0. 07 tooth row, better development of a cingulum along the external edge of 05 the anteroconid, and the presence of an ectostylid in the posteroexternal Wtri 10 0. 9-1. 1 1. 015 0. 058 W 11 1. 2-1. 4 1. 32 0. 065 valley (major fold) of m2. The Red Corral specimens are slightly smaller than most specimens assigned to Reithrodontomys rexroadensis with which they Wtal 10 1. 1-1. 2 1. 18 0. 042 M2 L 4 1. 3-1. 5 1. 43 0. 096 were compared but are tentatively referred to that species on the basis of similar size, a more pointed anteroconid, the absence of a prominent m2 L 5 1. 5-1. 6 1. 54 0. 055 W 4 1. 1-1. 2 1. 18 0. 05 anterolabial cingulum, and the absence of stylids in three of the four 1. 2-1. W 5 1. 24 0. 022 dentaries. 25 It is possible that the Red Corral specimens belong to an m3 L 1 1. 1 1. 1 undescribed species of Reithrodontomys or to R. galushai, another late W 1 1. 3 1. 3 Blancan species (see below), or that more than one taxon is represented. Red Corral Pit D The late Claude W. Hibbard examined the specimens and agreed that those with narrow tooth rows, pointed anteroconids, and a weak M1 L 5 1. 7-2. 2 1. 94 0. 195 capsular process (4393, 4396, and probably 4394) represent a small 1. 1-1. W 5 1. 21 0. 114 species of Reithrodontomys, whereas 4395 might equally represent a 35 large species of Baiomys the size of the Blancan B. kolbi Hibbard or the extant B. musculus because of the rounded anteroconid on m1 and the M2 L 2 1. 5-1. 6 1. 55 slightly better anterolophid on m2. W 2 1. 2 1. 2 According to Hibbard (1952a), Baiomys kolbi from the Fox Canyon LF is distinguished from Reithrodontomys rexroadensis by its smaller, less curved lower incisor, narrower diastema, broader and from the latest Blancan Borchers LF, Meade County, Kansas, is smaller more rounded anteroconid on m1, better developed anterolophid on than the Red Corral species and the single m3 in the right dentary, KU m2, less rectangular outline of m2, slightly larger m3, better developed 6466, is reduced and has a C-shaped occlusal pattern according to the capsular process, and shallower pterygoid fossa. Unfortunately, illustration in Hibbard (1942, pl. 1, fig. 11). The same is true for R. the diastemal portion of 4395 is broken, and the anterior part of the moorei from the Irvingtonian age Cudahy Fauna of Kansas (Paulson, incisor as well as the capsular process and pterygoid fossa are missing. 1961). However, the width of the remaining part of the incisor is as great as in Clearly, the genus Reithrodontomys is in need of revision. Any Reithrodontomys. The outline of m2 is rectangular, m3 is reduced and such revision should involve a comparison with small species of the anterolophid on m2 is no better developed than in some Holocene Peromyscus and with species of Baiomys. species of Reithrodontomys. For these reasons I am reluctant to assign Onychomys cf. pedroensis Gidley, 1922 4395 to Baiomys and, in the absence of a larger sample including the Figure 20D more diagnostic M3 and m3 and showing the range of variation in tooth characters, I am reluctant to erect a new species of Reithrodontomys Referred specimens. Pit C; 4398, left dentary fragment with m2 or to assign the Red Corral specimens to one of the Holocene species and m3; 4399, edentulous right dentary fragment; 4400, edentulous groups. right dentary fragment; 4401, isolated lower teeth including 10 m1s; 28 4402, left maxillary fragment with M1; 4403, isolated upper teeth. Pit incisor width is 0. 5. D: 4044, isolated teeth. A right dentary, 4371, of a young adult contains the incisor, Description. A left dentary fragment, 4398, of a grasshopper diastema, and m1-m3 but is broken posterior to m3. The diastema is mouse is broken just anterior to m2 and is missing the posterior 2. 6 long. The mental foramen is placed as in 4370, but the knob-like processes. The m2 and m3 indicate a mature adult in wear stage III or process is slightly more posterior and lies below the anterior root of IV of Carleton and Eshelman (1979). The m2 contains broad folds that m1 rather than ahead of it. A small foramen occurs between m3 and lack accessory cusps or cingula. The m3 has a narrower talonid and the ascending ramus. Labial jaw depth below m1 is 3. 4 and below is more triangular in outline than in specimens of Onychomys gidleyi the mental foramen is 2. 2. Compared with 4370, the teeth are less with which it was compared. Measurements of m2 are: length = 1. 5; worn. The anteroconid of m1 is bilobate but with a small anterostylid width = 1. 2. Measurements of m3 are: length = 1. 1; talonid length = in the anteromedial groove. The connection between the anteroconid 0. 5; talonid width = 1. 0. A broad, shallow valley separates m3 from and the protoconid and hypoconid is narrower due to less wear, thus the ascending ramus. giving the former a “bow tie” appearance. The m2 is squarer, and the Among the isolated lower teeth, 4401, from Pit C are 10 m1s in labial cingula in both m1 and m2 are less developed. The m3 shows an different wear stages. Cingula are weak or absent. One tooth possesses S-shaped pattern with the entoconid and hypoconid broadly confluent. a prominent mesostylid. Three teeth possess a vestigial bud for a third There is no third root on m1. The greatest length of m1-m3 is 3. 7, and root. Measurement summaries of the m1s as well as five m2s and a the length of m1-m2 is 2. 8. The incisor width is 0. 6. single m3 are given in Table 8. A right dentary fragment, 4372, belongs to an old adult. The The upper teeth, 4402 (Fig. 20D) and 4403, from Pit C include diastema is 2. 5 long and the labial jaw depth below m1 is 3. 7 and 11 M1s. Mesostyles and cingula are present on some of the teeth. below the mental foramen is 2. 3. Incisor width is 0. 6. Greatest length Measurement summaries of the M1s including five M1s, 4044, from of m1-m2, which are heavily worn, is 2. 85. There is a small third root Pit D are given in Table 8. Six M1s (43 %) of the combined sample on the labial side of m1 possess a tiny fourth root or nub beneath the paracone. The remaining dentary fragments and isolated m1s from Pit C Remarks. Measurements of the lower teeth from the Red Corral show only minor variations and are like those described above. Most LF were compared with those of Onychomys gidleyi (early Blancan) and m1s have well-developed labial cingula. The shape of m1 varies with O. pedroensis (late Blancan-early Irvingtonian) given by Carleton and the width of the anteroconid and development of the anteromedial Eshelman (1979). The average length of m1 and m2 exceeds the length groove. All but one specimen possess a bilobate anteroconid with of most O. gidleyi except the larger specimens from the Fox Canyon LF equally developed conulids. In 4374, this cusp is narrow and undivided but falls within the range of O. pedroensis from the Borchers and Curtis but still separated from the other cusps by wide valleys, and the tooth Ranch local faunas of Kansas and Arizona, respectively. However, the appears triangular and more pointed anteriorly than the others. The width of m1 and m2 as well as the length and width of the single m3 presence or absence of an anterostylid in the anteromedial groove and from Red Corral fall within the range of both species, although more of a third root on m1 is variable. The mean length and width of all 11 like O. pedroensis because of the smaller, reduced talonid on m3. The m1s (isolated and in jaws) from Pit C are 1. 60 (OR = 1. 5-1. 7; SD = 0. Red Corral specimens are larger than O. bensoni from Arizona and 061) and 1. 06 (OR = 1. 0-1. 15; SD = 0. 055), respectively. O. hollisteri, including the teeth from the Deer Park B LF of Kansas The dentaries from Pit C compare favorably in size and general referred to the latter by Martin et al. (2002b). morphology with a series of six dentaries (UMMP 29675) of Carleton and Eshelman (1979), using mandibles, demonstrated Bensonomys eliasi from Rexroad Locality 3, Kansas, in the University an evolutionary increase in length of the first and second molars at of Michigan collections and with a paratype dentary, KU 4547, at the the expense of the third molar in Onychomys. Unfortunately, the University of Kansas. The holotype, KU 3941, has teeth too worn for limited material from Red Corral precludes such comparisons with adequate comparison. The Pit C jaws are larger than the holotype of one exception. The ratio of the length of m3 to that of m2 in 4398 B. meadensis from the Sanders LF (Hibbard, 1956) or the holotype is 0. 73:1. 0, which matches most closely to that of O. pedroensis. A of B. arizonae from the Benson LF (Gidley, 1922; Gazin, 1942) but larger and better sample is needed to determine whether the Red Corral individual tooth measurements overlap in size with teeth assigned to grasshopper mouse actually represents O. gidleyi, O. pedroensis, or an B. eliasi from Rexroad Locality 3 and B. meadensis from Deer Park B, intermediate grade on the lineage leading to O. leucogaster as shown by Kansas, by Martin et al. (2002b) and teeth assigned to B. arizonae from Carleton and Eshelman (1979, p. 28). the early Blancan Verde LF, Arizona,by Czaplewski (1987a) and the 111 Ranch LF, Arizona, by Tomida (1987). Bensonomys cf. arizonae (Gidley, 1922) Three dentaries from Pit D are similar to those from Pit C but Figures 20E-F are slightly smaller. Specimens 4037 and 4038 are a right and left Referred specimens. Pit C: 4370-4377, eight tooth-bearing right dentary that show identical tooth wear pattern and preservation and dentaries and dentary fragments; 4379, isolated m1s; 4380-4386, four probably belong to a single young adult. The right dentary, 4037, is left and three right maxillary fragments; 4387, isolated M1s. Pit D: more complete and contains the incisor and m1-m3 but is broken across 4037, right dentary with incisor, m1-m3; 4038, left dentary fragment the diastema and posterior to m3 (Fig. 20E). The knob-like process with m1-m2; 4142, associated right and left lower dentitions; 4143, left on the masseteric crest turns upward; the mental foramen is dorsally dentary with m1-m2; 4144, isolated teeth. situated on the diastema ahead of m1. There is a shallow sulcus above Description. This cricetine rodent is well represented in the fauna the capsular process and a small foramen between m3 and the base of by 11 tooth-bearing dentaries or dentary fragments, seven maxillary the ascending ramus. Labial jaw depth below m1 is 3. 3 and below fragments, and a number of isolated teeth. A right dentary, 4370, of an the mental foramen is 2. 4. The anterior face of m1 is blunt, and the adult contains the incisor and m1-m3, the angular process and part of anteroconid is bilobate. Labial cingula are moderately developed on the coronoid process but is broken just anterior to the mental foramen. m1 and m2. The m3 is more reduced posteriorly. The greatest length A knob-like process occurs at the anterior extremity of the masseteric of m1-m3 is 3. 6 (m1 = 1. 5 x 1. 0; m2 = 1. 15 x 1. 0; m3 = 1. 0 x 0. 9). crest, and the mental foramen is dorsally placed on the diastema just Incisor width is 0. 55. above this process and just in front of the anterior root of m1. There A left dentary, 4143, of a young adult contains m1-m2 but lacks is a shallow sulcus above the capsular process for the incisor. A small the incisor (Fig. 20F). The diastema is 2. 5 long. The anteroconid on foramen occurs in the depression between m3 and the ascending ramus. m1 is inflated anteriorly but is not bilobate. Labial cingula are well- Labial jaw depth below m1 is 3. 2. The anteroconid on m1 is divided by developed. Length of m1-m2 is 2. 6 (m1 = 1. 45 x 1. 0; m2 = 1. 15 x a shallow anteromedial groove, with the labial conulid slightly larger 1. 0). than the lingual one. The protoconid and hypoconid are low, broad, No. 4142 consists of associated complete right and left lower and V-shaped with the V pointing posterolabially. The labial valleys dentitions including incisors of a young adult; most of the jaw bone has are open and broad, and a wide cingulum extends from the anteroconid deteriorated. Measurements are: m1 = 1. 6 x 1. 0; m2 = 1. 15 x 1. 0; m3 back to the protoconid and across the labial reentrant. The metaconid = 1. 0 x 0. 8. The m1 is two-rooted. The incisor width is 0. 5. Additional is widely separated from the anteroconid by a broad valley. There is a measurements of lower teeth and jaws from both Pit C and Pit D are third rootlet present. The m2 is sub rectangular with the anterior end summarized in Table 9 along with those of teeth from the Rexroad 3 wider than the posterior. The valleys are broad, and the anterior and and Deer Park B local faunas of Kansas and the Verde and 111 Ranch labial cingula are well-developed. The m3 tapers posteriorly but is not local faunas of Arizona. reduced. The anterior and labial cingula are slightly developed. The Associated with the dentaries at Pit C are seven tooth-bearing greatest length of m1-m3 is 3. 9, and the length of m1-m2 is 2. 9. The maxillary fragments and eight isolated M1s in various wear stages. 29 TABLE 9. Statistical summary of jaw and tooth measurements (in mm) of Bensonomys cf. arizonae from Red Corral Pits C and D and faunas in Kansas and Arizona. Abbreviations: L = length; W = width; Occl. = occlusal; Ld = labial jaw depth; mf = mental foramen. Pit C Pit C Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L 11 1. 5-1. 7 1. 6 0. 061 M1 L 14 1. 6-1. 8 1. 71 0. 068 W 11 1. 0-1. 15 1. 06 0. 055 W 14 1. 0-1. 15 1. 07 0. 054 m2 L 3 1. 15-1. 25 1. 2 M2 L 2 1. 2-1. 3 1. 25 W 3 0. 95-1. 1 1. 02 W 2 1 1 m3 L 2 1 1 W 2 0. 8 0. 8 m1-m3 Occl. L 2 3. 7-3. 9 3. 8 m1-m2 Occl. L 3 2. 8-2. 9 2. 85 Jaw Ld mf 3 2. 2-2. 3 2. 27 Jaw Ld m1 4 3. 2-3. 7 3. 45 Pit D Tooth Measure N OR Mean Tooth Measure N OR Mean m1 L 4 1. 45-1. 6 1. 51 M1 L 2 1. 8 1. 8 W 4 1 1 W 2 1. 1 1. 1 m2 L 4 1. 15 1. 15 W 4 1 1 m3 L 2 1 1 W 2 0. 8-0. 9 0. 85 m1-m3 Occl. L. 2 3. 6-3. 7 3. 65 m1-m2 Occl. L. 4 2. 6-2. 75 2. 66

Jaw Ld mf 1 2. 4 2. 4 Jaw Ld m1 1 3. 3 3. 3 Bensonomys eliasi from Rexroad Locality 3, Kansas. Measurements by author. Tooth Measure N OR Mean SD m1 L 23 1. 5-1.7 1. 59 0. 05 W 24 0. 9-1. 1 1. 02 0. 449 m2 L 16 1. 1-1. 2 1. 17 0. 043 W 16 0. 95-1. 1 1. 04 0. 038 m3 L 8 1. 0-1. 1 1. 02 0. 035 W 8 0. 8-0. 9 0. 88 0. 035 m1-m3 Occl. L 7 3. 7-3. 9 3. 79 0. 068 m1-m2 Occl. L 15 2. 6-2. 9 2. 76 0. 86 Bensonomys meadensis from Deer Park B, Kansas. Measurements from Martin et al (2000b). Tooth Measure N OR Mean Tooth Measure N OR Mean m1 L 3 1. 55-1. 6 1. 58 M1 L 2 1. 62-1. 65 W 3 0. 95-1. 02 0. 98 W 2 0. 99-1. 02 m2 L 2 1. 23-1. 24 M2 L 3 1. 12-1. 18 1. 14 W 3 0. 98-1. 09 1. 04 W 3 0. 88-0. 96 0. 92 Bensonomys arizonae from Verde LF, House Mtn., Arizona. Measurements from Czaplewski (1987a). Tooth Measure N OR Mean Tooth Measure N OR Mean m1 L 7 1. 54-1. 71 1. 59 M1 L 3 1. 61-1. 69 1. 66 W 6 1. 06-1. 16 1. 12 W 3 1. 08-1. 18 1. 13 m2 L 3 1. 13-1. 21 1. 17 M2 L 6 1. 14-1. 23 1. 19 W 3 1. 03-1. 15 1. 08 W 6 0. 98-1. 07 1. 04 m3 L 2 1. 04-1. 05 1. 04 M3 L 4 0. 8-0. 9 0. 85 W 2 0. 9-0. 92 0. 91 W 4 0. 83-0. 89 0. 87 m1-m3 Occl. L 2 3. 86-4. 12 3. 99 Bensonomys arizonae from 111 Ranch, Arizona. Measurements from Tomida (1987). Tooth Measure N OR Mean Tooth Measure N OR Mean m1 L 2 1. 54-1. 62 1. 58 M1 L 3 1. 52-1. 6 1. 57 W 2 0. 96-1. 06 1. 01 W 3 1. 02-1. 06 1. 04 m2 L 3 1. 12-1. 20 1. 15 M2 L 1 1. 12 W 3 0. 96-1. 08 1. 02 W 1 0. 92 m3 L 4 0. 96-1. 04 1. 01 M3 L 1 0. 82 W 4 0. 76-0. 88 0. 82 W 1 0. 78 m1-m3 Occl. L 1 3. 92 30 The anterocone is generally broad and divided anteromedially into or lophids in other teeth. M3s large. Size intermediate between that two equal or sub-equal conules. Labial cingula are weakly to strongly of Calomys baskini and Calomys elachys/Baiomys kolbi. ” They noted developed, and several M1s possess an anterocingulum at the base of comparisons with other species of the genus including C. (B. ) arizonae. the anterocone. In some teeth, accessory cusps (mesostyles) are present They stated (p. 76) that Calomys arizonae from the early Blancan Verde in the labial reentrant valleys, especially the first. A fourth labial root Formation of Arizona, strongly resembles C. winklerorum in size and is weakly developed in over 50 % of the M1s. M1-M2 length in two essential features but that it is higher-crowned, to the extent that the m1 specimens is 2. 85 and 2. 9. The mean length and width of 14 M1s anteroconid remains bilobed with moderate wear, and has no accessory (isolated and in max. fragments) from Pit C are 1. 71 (OR = 1. 6-1. 8; lophs or lophids. According to Martin et al. (2002a), B. hershkovitzi SD = 0. 068) and 1. 07 (OR = 1. 0-1. 15; SD = 0. 054), respectively. differs from all other species of the genus in having a long and narrow Additional upper tooth measurements are summarized in Table 9. dentine field of labial anterior cingulum connected to the dentine field Remarks. The taxonomic history of Bensonomys is complex. of anteroconid in minimal wear and by the presence of a mesolophid on Eligmodontia arizonae Gidley, 1922 from the Blancan age Benson LF m1. Kelly (2007, p. 126) gave a lengthy diagnosis of B. lindsayi and a of Arizona became the type species of the genus Bensonomys (Gazin, lengthy and detailed comparison with other species in terms of size and 1942). Gazin, however, noted many similarities between the extinct morphological features that will not be repeated here. North American genus and the Quaternary South American phyllotine Comparison of the Red Corral Bensonomys with the known Eligmodontia. Blancan species is more relevant to this paper. Hibbard (1956) Hibbard (1938) named Peromyscus eliasi from the Rexroad distinguished Bensonomys eliasi from the similar-sized B. arizonae on Locality 3 LF, Meade County, Kansas on the basis of a dentary with much the basis of a wider lower incisor, an m1 that is more rectangular with worn teeth and later (Hibbard, 1941c) referred additional material from a broad versus triangular anteroconid, and broader reentrant valleys in the same fauna to Eligmodontia? arizonae. In 1950, he synonymized P. m1 and m2. He distinguished Bensonomys meadensis from B. eliasi eliasi and E. ? arizonae with Bensonomys arizonae and assigned to that by its smaller size and narrower lower incisor. He differentiated B. species a series of dentaries from the Fox Canyon LF in Meade County, meadensis from B. arizonae by the position of the masseteric crest. which, he noted, were larger than the holotype and showed considerable The anterior end of the masseteric crest in B. meadensis is said to be variation in enamel pattern and size (Hibbard, 1950). In 1956, he more dorsal and more posterior to the mental foramen. He considered recognized B. eliasi as a valid species to which he referred both the both B. meadensis and B. arizonae to have similar shaped m1s, with a Rexroad and Fox Canyon forms and also described a smaller species, rectangular-shaped anteroconid, in contrast to the broad anteroconid he B. meadensis, from the Sanders LF also in Meade County (Hibbard, attributed to B. eliasi. However, Czaplewski (1987a) stated that, in the 1956). Earlier, Hibbard (1953b) described Cimarronomys stirtoni from absence of quantified differences and comparative specimens, he could the earliest Blancan Saw Rock Canyon LF in Meade County. This not distinguish specimens from the Verde Formation of Arizona that he species was later included as a species of Bensonomys (Baskin, 1978) assigned to B. arizonae from the other two species. Martin et al. (2002b) and, more recently, listed as a species of Symmetrodontomys (Martin et assigned a sample of teeth from Deer Park B to B. meadensis. Martin al., 2008; Martin and Peláez-Campomanes, 2014). et al. (2008) and Martin and Peláez-Campomanes (2014) continued to Baskin (1978) considered there to be a close relationship between recognize the Fox Canyon species as B. eliasi but assigned the Rexroad Eligmodontia and Bensonomys and made the latter a subgenus of 3 fossils to B. meadensis while continuing to recognize the Deer Park Calomys, another South American phyllotine. He noted that Calomys and Sanders specimens as belonging to the latter species. differs from Eligmodontia in having more brachydont teeth and a more The Red Corral specimens from Pit C compare favorably in size bifurcated anterocone (-id), and that the absence of super numerary and morphology with specimens from Rexroad Locality 3 and Deer Park roots in teeth of Calomys (Bensonomys) is not a consistent and B whereas some of the specimens from Pit D are smaller and compare diagnostic characteristic as Hibbard (Skinner et al., 1972) had thought better in size with B. meadensis. However, there is considerable overlap since extra roots may be present in some species. He also described in size between teeth from Rexroad Locality 3 and Deer Park B and teeth a small species, C. (B. ) yazhi, and a larger species, C. (B. ) gidleyi, assigned to B. arizonae from the Verde and 111 Ranch local faunas of from the late Hemphillian White Cone LF, Bidahochi Formation, Arizona (Table 9). Martin (written communication, 2015) indicated that Arizona, and reviewed the evolutionary and zoogeographic history many of the features used by Hibbard to separate these three species are of the genus. Dalquest (1983) described C. (B. ) coffeyi from the late highly variable and that B. arizonae, B. eliasi, and B. meadensis may be Hemphillian Coffee Ranch LF, Hemphill County, Texas. Lindsay and conspecific. He suggested that the Red Corral specimens be assigned to Jacobs (1985) described a small species, C. (B. ) elachys, and a large B. arizonae, the earliest named of the three species and I have followed species, C. (B. ) baskini, from the late Hemphillian Yepomera and his suggestion. early Blancan Concha local faunas, Chihuahua, Mexico. Carranza- Sigmodon minor /medius Gidley, 1922 Castañeda and Walton (1992) described C. (B. ) winklerorum from Figure 21E the latest Hemphillian or earliest Blancan El Cote Fauna, Guanajuato, Mexico. Martin et al. (2002b) considered Bensonomys to be a primitive Referred specimens. Pit C: 4404-4419, 16 tooth-bearing left phyllotine closely related to Calomys but, because of its plesiomorphic dentaries and dentary fragments; 4420-4428, 9 tooth-bearing right features, they opted to return Bensonomys to generic status. Martin et dentaries and dentary fragments; 4378, two edentulous left dentary al. (2002a) described B. hershkovitzi from the late Hemphillian Pipe fragments; 4429-4441, 13 tooth-bearing left maxillary fragments; Creek Sinkhole, Grant County, Indiana. Kelly (2007) reviewed the 4442-4455, 14 tooth-bearing right maxillary fragments; 4456, isolated systematic history of Bensonomys and described B. lindsayi from the teeth. Pit D: 4048-4057, 4072-4077, 4146-4157, 28 tooth-bearing left early late Hemphillian Coal Valley Formation of Smith Valley, Nevada. dentaries and dentary fragments; 4058-4071, 4158-4171; 4187-4192, 34 To date, a total of 12 species of Bensonomys have been described tooth-bearing right dentaries and dentary fragments; 4078, edentulous in the literature making detailed comparisons difficult. Future work dentary fragments; 4079-4084, 4193-4194, eight left maxillary may show some of these to be conspecific. Lindsay and Jacobs (1985) fragments with M1-M3; 4085, 4195-4197, four right maxillary stated that Calomys (Bensonomys) elachys is a small species about the fragments with M1-M3; 4086, edentulous maxillary fragments; 4087, size of C. (B. ) yazhi whereas C. (B. ) baskini is about the size of C. isolated teeth. (B. ) stirtoni. According to Tomida (1987, p. 96), C. (B. ) stirtoni and Description. This small and primitive cotton rat is by far the most C. (B. ) baskini are much larger than C. (B. ) arizonae, the genotypic abundant taxon in the Red Corral LF at both Pits C and D (Fig. 21E). species, whereas C. (B. ) yazhi, and C. (B. ) gidleyi are smaller than A total of 12 tons of matrix was screen washed from Pit C and 28 tons C. (B. ) arizonae. C. (B. ) yazhi also differs from the latter by having from Pit D. Based on a count of lower m1s obtained, the minimum a better developed posterior cingulum on M1 and by having three- number of individuals from Pit C is 40 (40 left m1s and 38 right m1s) rooted m2 and m3. C. (B. ) gidleyi also differs from C. (B. ) arizonae and from Pit D is 139 (120 left m1s and 139 right m1s). The large by having a mesoloph on M1. Czaplewski (1987a) gave further sample size permits a statistical analysis of both upper and lower molars comparisons with C. (B. ) arizonae and also commented that C. (B. ) and allows comparisons with samples of this taxon from other Blancan coffeyi is the same size as C. (B. ) arizonae but that Dalquest’s diagnosis faunas in the Southern High Plains and the southwestern United States. could be applied to almost any species of C. (Bensonomys). Carranza- Tooth morphology of the Red Corral cotton rat is consistent with that Castañeda and Walton (1992, p. 76) diagnosed C. (B. ) winklerorum as given by R. A. Martin (1979) in his emended diagnosis of the medius follows: “M1 has sub equally bilobed anterocone with a moderately species group of Sigmodon and also with that given by Tomida (1987). deep anteromedian groove; m1 bilobed only in earliest stages of wear. Martin notes that relative to all other Sigmodon species, the dentition Tendency to retain short, narrow mesoloph on M1, no auxiliary lophs is brachydont and that reentrant folds on all teeth are relatively 31 shallow. Tomida (1987, p. 98) further states that “cusps of cheek teeth longer and 4 to 6 % narrower than that of the Rexroad sample. Molars are anteroposteriorly compressesd and lophate; cusps of upper teeth in the Wendell Fox sample are larger than those in the Red Corral slope slightly anteriorly, whereas cusps of lower teeth slope slightly samples in nearly all dimensions. There is also variation within and posteriorly. Cusps and lophs are relatively inflated almost robust, and between the Arizona samples. In sum, the large size of the Red Corral correspondingly the flexa and flexids are relatively deep and narrow. ”A samples will permit additional statistical analyses and comparisons to well-developed anterior cingulum is present on m2 and m3. Detailed be made beyond those attempted in this paper. morphologies of each molar are given by Tomida (1987) and are not The lower m1 of Sigmodon minor /medius is characterized by two repeated here. Measurement summaries of the Red Corral molars are well-developed roots – one anterior and one posterior. In addition, one or given in Table 10. As mentioned above, greatest length and width of two accessory rootlets may be present between them as tiny pegs. When the teeth were measured to the nearest 0. 05 mm using an ocular grid one rootlet is present it is usually in a labial position but it may occur in a binocular microscope and viewing the teeth perpendicular to the rarely in a medial position. In rare instances, two accessory rootlets occlusal surface. Although immature tooth caps and extremely worn may be present – one labial and the other lingual. In many instances or weathered teeth were excluded from the measurement sample, it is the position of an accessory rootlet is marked by only a slight bump. possible that the measured length of some teeth is biased by about 0. Hibbard in Skinner et al. (1972) emphasized the taxonomic utility of 1 mm longer because of the cusp inflation and the anterior or posterior dental root morphology, particularly within the genus Sigmodon. At slope of the teeth mentioned by Tomida. The tooth dimensions of the present, only the lower m1 appears to have extensive taxonomic utility Pit C and Pit D samples are very similar. The mean dimensions of with regard to the development of accessory rootlets (Martin, 1979). In the lower molars from Pit D range from 0. 00 to 0. 06 greater than a sample of 62 lower m1s from Red Corral Pit C, four (6. 5 %) have two those from Pit C. The mean dimensions of the upper molars from both accessory rootlets, 24 (39 %) have one accessory rootlet (22 labial and sites are nearly identical. Table 10 also gives tooth measurements of two medial in position), seven (11 %) have a slight “bump”, and 27 (43. specimens collected from Rexroad Locality 3 and other localities in the 5 %) have no accessory rootlet. In a sample of 156 lower m1s from Red Meade Basin of Kansas as well as from several Blancan local faunas Corral Pit D, six (4 %) have two accessory rootlets, 73 (47 %) have one in Arizona. Data come from Peláez-Campomanes and Martin (2005), accessory rootlet (64 labial and nine medial in position), 17 (11 %) have Czaplewski (1987a), and Tomida (1987). Compared with the Rexroad a slight bump, and 60 (38. 5 %) have no accessory rootlet. 3 sample, the mean length of the lower m1 and m2 in the Red Corral Accessory rootlets may be present occasionally in the upper M1s. sample is 6 to 11 % greater, although the mean length of the lower m3 is In a sample of 130 upper M1s from Red Corral Pit D, six (4. 6 %) 5 to 7 % shorter. Mean width of the lower m1 and m2 in the Red Corral possess a tiny accessory rootlet labially between two of the three major sample, however, is 3 to 6 % shorter. Dimensions of the upper M1 and roots. A tiny bump is present in this position in 11 % of both the Pit C M2 vary from 2 % shorter to 5 % greater. The Red Corral M3 is 8 % and Pit D samples.

FIGURE 21. Neotoma (Paraneotoma) cf. fossilis: A, both maxillaries, M1-M2, 4457, Pit C; B, left maxillary, M1-M2, 4458, Pit C; C, associated left and right m1-m3, 4045, Pit D; D, right m1, 4047, Pit D. Sigmodon minor /medius: E, left dentary with incisor, m1-m3, 4048, Pit D. 32 TABLE 10. Statistical summary of tooth measurements (in mm) of Sigmodon minor/medius from Red Corral Pits C and D and other Blancan local faunas. Abbreviations: L = length; W = width; alv. = alveolar Red Corral Pit C Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L 75 1. 9-2. 5 2. 2 0. 12 M1 L 78 1. 8-2. 5 2. 12 0. 127 W 75 1. 2-1. 55 1. 35 0. 077 W 78 1. 4-1. 9 1. 63 0. 115 m2 L 58 1. 5-2. 0 1. 66 0. 101 M2 L 60 1. 4-2. 0 1. 61 0. 118 W 58 1. 3-1. 75 1. 49 0. 094 W 60 1. 3-1. 9 1. 55 0. 113 m3 L 5 1. 5-2. 1 1. 8 0. 136 M3 L 48 1. 3-1. 7 1. 49 0. 084 W 5 1. 3-1. 7 1. 46 0. 098 W 48 1. 2-1. 7 1. 37 0. 099 m1-m3 L 4 5. 1-5. 55 5. 3 0. 212 M1-M3 L 0 m1-m2 L 8 3. 3-4. 15 3. 71 0. 256 m1-m3 L alv. 2 5. 2-5. 9 5. 55 Red Corral Pit D m1 L 252 2. 0-2. 5 2. 26 0. 105 M1 L 217 1. 7-2. 5 2. 12 0. 139 W 252 1. 0-1. 55 1. 38 0. 07 W 217 1. 2-1. 9 1. 61 0. 111 m2 L 206 1. 4-2. 0 1. 72 0. 108 M2 L 149 1. 3-1. 9 1. 59 0. 11 W 206 1. 1-1. 8 1. 52 0. 093 W 149 1. 2-1. 8 1. 58 0. 111 m3 L 125 1. 5-2. 2 1. 84 0. 139 M3 L 111 1. 3-1. 7 1. 5 0. 1 W 125 1. 2-1. 7 1. 46 0. 092 W 111 1. 1-1. 6 1. 39 0. 107 m1-m3 L 28 5. 2-6. 0 5. 56 0. 214 M1-M3 L 12 5. 0-5. 7 5. 2 0. 25 m1-m2 L 50 3. 6-4. 2 3. 86 0. 158 m1-m3 L alv. 19 5. 2-6. 0 5. 68 0. 243 All Kansas data after Peláez-Campomanes and Martin (2005) Rexroad Loc. 3A, Kansas Rexroad Loc. 3B, Kansas Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L 39 1. 75-2. 36 2. 03 0. 122 M1 L 3 1. 97-2. 30 2. 17 W 41 1. 27-1. 65 1. 43 0. 073 W 3 1. 51-1. 65 1. 56 m2 L 23 1. 33-1. 81 1. 56 0. 096 M2 L 3 1. 50-1. 59 1. 54 W 23 1. 39-1. 68 1. 56 0. 07 W 3 1. 53-1. 61 1. 57 m3 L 15 1. 75-2. 14 1. 93 0. 115 M3 L 1 1. 39 W 15 1. 34-1. 64 1. 48 0. 077 W 1 1. 45 Wendell Fox Pasture, Kansas m1 L 8 2. 07-2. 34 2. 24 0. 087 M1 L 6 2. 19-2. 53 2. 31 0. 138 W 9 1. 41-1. 59 1. 5 0. 061 W 6 1. 66-1. 97 1. 8 0. 112 m2 L 8 1. 52-1. 85 1. 72 0. 106 M2 L 3 1. 56-1. 96 1. 77 W 8 1. 51-1. 75 1. 62 0. 077 W 3 1. 85-1. 97 1. 89

m3 L 2 1. 89-1. 92 1. 91 W 2 1. 50-1. 68 1. 59 Deer Park, Kansas m1 L 7 1. 91-2. 08 1. 98 0. 061 M1 L 8 1. 96-2. 33 2. 16 0. 135 W 13 1. 23-1. 56 1. 38 0. 098 W 8 1. 54-1. 85 1. 67 0. 124 m2 L 7 1. 31-1. 61 1. 51 0. 106 M2 L 4 1. 40-1. 50 1. 44 W 7 1. 45-1. 61 1. 55 0. 061 W 4 1. 38-1. 64 1. 52 m3 L 7 1. 61-1. 95 1. 79 0. 152 M3 L 4 1. 39-1. 57 1. 48 W 7 1. 33-1. 56 1. 48 0. 081 W 4 1. 23-1. 61 1. 45 Sanders 2, Kansas m1 L 9 1. 94-2. 14 2. 04 0. 095 W 10 1. 21-1. 50 1. 41 0. 085 m2 L 8 1. 40-1. 69 1. 54 0. 085 W 8 1. 53-1. 68 1. 6 0. 052 m3 L 6 1. 88-2. 14 1. 96 0. 1 W 6 1. 44-1. 64 1. 54 0. 072 33 Tusker LF Loc. 15-24 111 Ranch, Arizona (after Tomida, 1987) Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L 121 1. 84-2. 28 2. 03 0. 093 M1 L 113 1. 80-2. 28 2. 04 0. 102 W 139 1. 28-1. 60 1. 41 0. 063 W 121 1. 36-1. 80 1. 59 0. 092 m2 L 149 1. 40-1. 68 1. 55 0. 066 M2 L 94 1. 32-1. 64 1. 44 0. 064 W 150 1. 36-1. 68 1. 55 0. 064 W 96 1. 36-1. 92 1. 58 0. 094 m3 L 92 1. 52-2. 08 1. 79 0. 118 M3 L 46 1. 28-1. 60 1. 43 0. 094 W 93 1. 32-1. 72 1. 48 0. 083 W 45 1. 20-1. 52 1. 37 0. 074 m1-m3 L 25 5. 31-5. 94 5. 64 0. 176 M1-M3 L 9 4. 75-5. 75 5. 43 0. 278 Duncan LF Loc. 7937, Arizona (after Tomida, 1987) m1 L 6 2. 00-2. 28 2. 13 0. 106 M1 L 12 2. 00-2. 24 2. 11 0. 075 W 6 1. 32-1. 52 1. 44 0. 084 W 12 1. 60-1. 72 1. 67 0. 033 m2 L 7 1. 48-1. 64 1. 54 0. 06 M2 L 14 1. 44-1. 56 1. 52 0. 039 W 7 1. 40-1. 60 1. 54 0. 083 W 13 1. 48-1. 72 1. 61 0. 062 m3 L 10 1. 52-1. 96 1. 82 0. 131 M3 L 14 1. 36-1. 60 1. 49 0. 071 W 10 1. 28-1. 60 1. 51 0. 1 W 14 1. 28-1. 56 1. 48 0. 074 m1-m3 L 2 5. 67-5. 92 5. 8 Verde LF. Arizona (after Czaplewski, 1990) m1 L 4 1. 98-2. 37 2. 24 M1 L 5 1. 74-2. 23 2. 1 W 4 1. 30-1. 51 1. 45 W 5 1. 51-1. 77 1. 67 m2 L 5 1. 70-1. 93 1. 82 M2 L 5 1. 63-1. 80 1. 73 W 6 1. 54-1. 69 1. 64 W 5 1. 57-1. 84 1. 71 m3 L 2 2. 10-2. 26 2. 18 M3 L 5 1. 34-1. 56 1. 49 W 3 1. 43-1. 67 1. 57 W 5 1. 44-1. 61 1. 55 m1-m3 L 2 6. 20-6. 33 6. 26 M1-M3 L 1 5. 3 Borchers LF, Kansas Tooth Measure N OR Mean SD Tooth Measure N OR Mean SD m1 L 49 1. 72-2. 22 1. 92 0. 127 M1 L 14 1. 80-2. 40 2. 14 0. 153 W 51 1. 14-1. 48 1. 29 0. 076 W 15 1. 35-1. 63 1. 5 0. 079 m2 L 56 1. 22-1. 78 1. 42 0. 12 M2 L 14 1. 25-1. 75 1. 5 0. 124 W 54 1. 20-1. 55 1. 41 0. 078 W 14 1. 19-1. 63 1. 5 0. 126 m3 L 32 1. 40-1. 84 1. 66 0. 12 M3 L 8 1. 23-1. 57 1. 38 0. 099 W 30 1. 20-1. 50 1. 34 0. 075 W 8 1. 18-1. 43 1. 31 0. 088 UA Loc. 25-3 Curtis Ranch, Arizona (after Tomida, 1987) m1 L 4 1. 88-2. 12 1. 99 0. 1 M1 L 8 1. 88-2. 04 1. 99 0. 06 W 5 1. 28-1. 36 1. 32 0. 04 W 8 1. 48-1. 60 1. 52 0. 043 m2 L 5 1. 24-1. 44 1. 34 0. 092 M2 L 6 1. 20-1. 40 1. 31 0. 07 W 6 1. 32-1. 52 1. 44 0. 08 W 6 1. 28-1. 52 1. 44 0. 091

m3 L 3 1. 56-1. 68 1. 63 M3 L 2 1. 24-1. 36 1. 3 W 3 1. 28-1. 44 1. 35 W 2 1. 20-1. 40 1. 3 m1-m3 L 3 5. 08-5. 50 5. 36 M1-M3 L 1 5. 42 Accessory rootlet data for a sample of lower m1s from the Rexroad Kansas, document a phyletic decrease in body size during late Blancan Locality 3 LF are provided by Martin (1979). Similar data for both time that culminated in the diminutive S. minor/minor in the latest upper and lower first molars in several Blancan faunas in Arizona are Blancan Borchers LF. S. minor /medius is a common member of early given by Tomida (1987). and middle Blancan faunas in Kansas, Texas, Arizona, and California, Remarks. Gidley (1922) described 3 species of Sigmodon from and Martin (1993) notes that cotton rats are the ecological analogues of Arizona: S. medius from the early Blancan Benson LF; S. minor, their northern arvicolid cousins, members of the genus Microtus, and a smaller cotton rat, from the late Blancan Curtis Ranch LF; and S. that they generally replace Microtus wherever the two are sympatric. curtisi, a large cotton rat, also from the Curtis Ranch LF. Sigmodon It should be noted here that no arvicolids (microtines) were recovered intermedius was described by Hibbard (1938) based on fossils from from the Red Corral LF. The predominance of Sigmodon, a grazer, in Rexroad Locality 2 and later Rexroad Locality 3. Hibbard characterized the Red Corral LF indicates that some kind of mesic or semi-mesic S. intermedius as intermediate in size between S. curtisi and S. medius. lowland environment was present. For more detailed information on Cantwell (1969) synonymized S. intermedius and S. minor with S. the evolution and dispersal of cotton rats, the reader is referred to medius. Statistical comparisons later led Martin (1970) also to consider Martin (1979, 1986, 1993), Martin et al. (2002b, 2003), and Peláez- S. intermedius to be synonymous with S. medius. Later, Martin (1979) Campomanes and Martin (2005). designated the subspecies S. medius medius distinct from S. minor from Curtis Ranch. Still later, Martin (1986) synonymized S. medius and Neotoma (Paraneotoma) cf. fossilis Gidley, 1922 S. minor as populations S. minor /medius and S. minor /minor, which Figures 21A-D; 22-27 represent stages or chronomorphs on a chronocline that, at least in Referred specimens. Pit C: 4457, palate with left and right M1- 34

FIGURE 22. Graph showing range of variation in length (L) and width (W) in millimeters of M1s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: s = sawrockensis; f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 23. Graph showing range of variation in length (L) and width (W) in millimeters of m1s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D. 35

M2’s

FIGURE 24. Graph showing range of variation in length (L) and width (W) in millimeters of M2s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; t = taylori; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 25. Graph showing range of variation in length (L) and width (W) in millimeters of m2s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: s = sawrockensis; f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D. 36

FIGURE 26. Graph showing range of variation in length (L) and width (W) in millimeters of M3s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; C = Proctor Pit C; D = Proctor Pit D.

FIGURE 27. Graph showing range of variation in length (L) and width (W) in millimeters of m3s in various Neotoma species. Intersections of vertical and horizontal lines indicate mean values of length and width. Dots represent individual specimens. Abbreviations: f = fossilis; v = vaughani; l = leucopetrica; t = taylori; R3 = Rexroad Loc. 3; DP = Deer Park; C = Proctor Pit C; D = Proctor Pit D. 37 1. 99 (1. 8-2. 2) and 1. 89 (1. 7-2. 1), respectively. The average length/ M2; 4458, left maxillary with M1-M2; 4459, left maxillary fragment; width ratios are 1. 59 (1. 43-1. 78) for Pit C and 1. 63 (1. 48-1. 84) 4460, left maxillary fragment; 4461, isolated teeth. Pit D: 4045, for Pit D. By comparison, the average length of 30 m1s from Rexroad associated left m1-m3 and right m1-m3 of one individual; 4046, left Locality 3 is 3. 39 (2. 96-3. 80), and the average width is 1. 86 (1. 56-2. maxillary fragment with M1; 4047, isolated teeth. 13) according to Martin et al. (2002b). Of 18 M1s from Pit C and 19 Description. The wood rat from the two Red Corral pits is M1s from Pit D, the average lengths are 3. 31 (3. 1-3. 5) and 3. 25 (3. represented mainly by isolated teeth. No dentaries or dentary fragments 0-3. 5), respectively, and the average widths are 2. 28 (2. 15-2. 5) and were recovered, although a complete left and right lower dentition (Fig. 2. 25 (2. 1-2. 4), respectively. The average length/width ratios are 1. 45 21C) was found in one washer box, and there is also a palate with both (1. 36-1. 55) for Pit C and 1. 45 (1. 25-1. 59) for Pit D. By comparison, left and right M1s and M2s (Fig. 21A) and a left maxillary with M1 the average length of 10 M1s from Rexroad Locality 3 is 3. 58 (2. 96-3. and M2 (Fig. 21B). The teeth exhibit characteristics of the subgenus 86), and the average width is 1. 96 (1. 68-2. 34) (Martin et al., 2002b). Paraneotoma, including the S-shaped m3. They are moderately low- Other measurements of N. quadriplicata teeth from Rexroad Locality crowned and are smaller with thinner enamel than those of Neotoma 3 as well as those from Deer Park B are given by Martin et al. (2002b). quadriplicata from Rexroad Locality 3 with which they were compared. According to Zakrzewski (1993), the number of anatomical roots In the lower molars, the apices of the labial folds (flexids) are in wood rats is a character that appears to be in a state of flux. All nearly perpendicular to the long axis of the tooth, whereas the apices Blancan wood rats that he examined have two major roots on each of of the lingual folds (flexids) are directed anterolabially to the long axis. their lower molars, and three on their uppers. He noted that a small In the lower m1s (e. g. Fig. 21D), the anterolophid is confluent and the accessory root may be found, usually equidistant from the three major anterolingual fold is poorly developed or absent. In younger individuals, ones, on the M1 in Blancan taxa. The Red Corral teeth conform to this the fold is broad, shallow, and not deep so that it is generally lost with pattern. Nearly all of the upper M1s in which the roots are preserved wear. The apex of the posterolabial fold is significantly anterior to the possess a tiny nub in the position of the fourth rootlet. In four M1s from apex of the posterolingual fold, giving the mesolophid a constricted or Pit C, a tiny rootlet measures 0. 2, 0. 3, 0. 3, and 0. 4 in length, and staggered appearance with its labial end well anterior to its lingual end. in three M1s from Pit D, a tiny rootlet measures 0. 3, 0. 3, and 0. 4 in The posterolophid is confluent. length. In two M3s from each locality, the two anterior roots are fused. The lower m2 is similar to the m1 in having three major lophids, Remarks. Hibbard (1967) erected the subgenus Paraneotoma but all are confluent. The mesolophid is diagonal to the long axis of to include three species: Neotoma (Paraneotoma) quadriplicatus, N. the tooth with the labial apex more anterior than the lingual. With wear (P. ) sawrockensis, and N. (P. ) taylori. Tomida (1987) demonstrated the anterior labial fold and the posterior lingual fold disappear, and the that N. fossilis Gidley from the early Blancan Benson and Duncan tooth acquires an S-shaped pattern. In the lower m3, the anterolabial (UA loc. 7937) local faunas of Arizona also shares the characteristics fold and the posterior lingual fold are not developed, and the tooth has of Paraneotoma, and he referred it to that subgenus. Czaplewski the S-shape characteristic of the subgenus Paraneotoma. (1990) named Neotoma vaughani from the early Blancan Verde LF In the upper M1 and M2, the labial folds (flexi) extend of Arizona and referred it to the same subgenus. Zakrzewski (1991) posterolingually with the tips bent further posteriorly, whereas the named N. leucopetrica from the late Blancan White Rock LF of Kansas lingual folds (flexi) are nearly perpendicular to the long axis of the tooth. (Eshelman, 1975) and assigned it to the same subgenus. These six In M1, the anteroloph is confluent. The anterolingual fold is slightly to species share similar but somewhat variable tooth morphologies and poorly developed and is quickly lost with wear. The anterolabial fold are distinguished to some extent by molar size, crown height, and depth and the mesolingual fold meet at the approximate midline of the tooth, of the reentrant folds (flexi and flexids). The Red Corral wood rat teeth thus separating the diagonally aligned anteroloph from the diagonally are larger than those of N. sawrockensis from the earliest Blancan Saw aligned mesoloph. M2 is similar to M1. The anteroloph is confluent, Rock Canyon LF of Kansas (Hibbard, 1967) and are slightly larger and the anterolingual fold is not present. As in M1, the anterolabial fold or overlap in size those of N. fossilis from Arizona (Gidley, 1922; and the shallow mesolingual fold are arranged so that the diagonally Tomida, 1987). They approximate in size the few described teeth of N. aligned anteroloph is set off from the diagonally aligned mesoloph. The vaughani. As noted above, the Red Corral teeth are smaller and have posteroloph is confluent and hook-like. M3 is similar to M2. All three thinner enamel than those of N. quadriplicata from Rexroad Locality lophs are confluent, and the anteroloph is set off from the mesoloph. 3, and they are also smaller than teeth from the Deer Park LF referred The mesolingual fold is shallow, giving the tooth an E-shape. The to N. quadriplicata by Martin et al. (2002b). The Red Corral teeth are posterolingual fold is absent in all three upper molars. A statistical smaller than those of N. taylori with which they were compared from summary of tooth measurements from both Pits C and D is given in the Borchers LF of Kansas (Hibbard, 1967). They are also smaller than Table 11. teeth referred to N. taylori from UA locality 15-24, 111 Ranch LF of Zakrzewski (1991, 1993) states that the folds are deeper and closer Arizona, but overlap in size teeth referred to that species from UA loc. to the base of the crown in extant taxa than in extinct ones, and that 7933, 111 Ranch (Tomida, 1987). N. taylori is the most hypsodont this controls the occlusal pattern at different stages of wear. In the Red species within the subgenus Paraneotoma. As a result, the side walls of Corral teeth, the distances from the base of the crown to the base of the cheek teeth are straighter (or less curved) than in other species of the the folds is less than that seen in other Blancan taxa such as Neotoma subgenus, and, thus, the cheek teeth of N. taylori are less rounded or less quadriplicata from Rexroad Locality 3 and Deer Park (Martin et al., inflated in appearance, especially in the lower molars (Tomida, 1987). 2002b) and N. leucopetrica from the White Rock LF (Zakrzewski, The largest species in this subgenus is N. leucopetrica, and the smallest 1991). This discrepancy is probably the result of the smaller size and is N. sawrockensis. Dalquest (1978) assigned several teeth from the more brachydont nature of the Red Corral teeth so that in a relative Beck Ranch LF to N. cf. sawrockensis, but Tomida (1987) noted that sense the folds are not as deep. Crown depths of the Red Corral teeth these teeth appear to be slightly larger and higher crowned than that are also given in Table 11. It should be noted that the bases of the folds species and more equivalent in size to the teeth from the Duncan LF on m2 in the Red Corral sample are at a greater distance from the base that he assigned to N. fossilis. C. A. Repenning tentatively identified the of the crown than in m1. Zakrzewski (1991) found this to be the case in Beck Ranch fossils as N. fossilis (pers. comm. to Tomida, Jan. 1981). N. leucopetrica as well. A comparison of the length and width of the molars of several species The lower molars and the upper M3 from Pit D average 0. 1 of Neotoma from Blancan faunas in Kansas and Arizona is given in shorter and narrower than those from Pit C, whereas the upper M1s Figures 22-27. and M2s from the two sites are nearly equal in size. Very likely the Zakrzewski (2006) noted the variation in tooth dimensions of same species is represented at both localities. In general, the Red Corral woodrat samples from the Meade Basin in southwestern Kansas teeth are smaller than those of Neotoma quadriplicata from Rexroad including published sites such as Saw Rock Canyon, Rexroad Locality Locality 3, although there is some overlap in size. In particular, the 3, and Borchers as well as from several unpublished sites (e. g. XIT 1B m1s, m2s, and M1s average 0. 25-0. 4 shorter and 0. 05-0. 33 wider and Wendell Fox). He concluded that the data “suggest the presence than those from Rexroad Locality 3, whereas the m3s are 0. 15-0. 25 of two additional woodrats in the basin, a small taxon at XIT 1B that shorter and 0. 15-0. 3 narrower. No measurements of the M2s and M3s may be in a lineage with Neotoma sawrockensis and a larger taxon at from Rexroad Locality 3 were available for comparison. Of 15 m1s Wendell Fox that may be in a lineage with N. leucopetrica. ” He did not from Pit C and 13 (of 14) m1s from Pit D, the average lengths are 3. 15 name these taxa and, until the geographic and biostratigraphic variation (3. 0-3. 3) and 3. 06 (2. 8-3. 5), respectively, and the average widths are within and between populations of Blancan woodrats in the central and 38 TABLE 11. Statistical summary of tooth measurements (in mm) of Neotoma (Paraneotoma) cf. fossilis from Red Corral Pits C and D. Measurements and abbreviations after Zakrzewski (1991): L = greatest occlusal length; W = greatest occlusal width; L/W = length/width ratio; ab = height of anterobuccal (labial) fold above base of crown; pb = height of posterobuccal (labial) fold above base of crown; al = height of anterolingual fold above base of crown; ml = height of mesolingual fold above base of crown; pl = height of posterolingual fold above base of crown. Red Corral Pit C Measure N OR Mean SD Measure N OR Mean SD m1 L 15 3. 0-3. 3 3. 15 0. 112 M1 L 18 3. 1-3. 5 3. 31 0. 128 W 15 1. 8-2. 2 1. 99 0. 118 W 18 2. 15-2. 5 2. 28 0. 09 L/W 15 1. 43-1. 78 1. 59 0. 102 L/W 18 1. 36-1. 55 1. 45 0. 05 ab 14 0. 2-0. 8 0. 43 0. 161 ab 18 0. 2-0. 6 0. 41 0. 102 pb 14 0. 2-0. 8 0. 47 0. 168 pb 18 0. 2-0. 5 0. 37 0. 083 al 2 1. 5-1. 7 1. 6 al 9 0. 4-1. 1 0. 88 0. 217 ml 14 0. 3-0. 8 0. 59 0. 144 ml 16 0. 3-0. 7 0. 52 0. 169 pl 13 0. 4-1. 0 0. 71 0. 173 m2 L 14 2. 6-2. 9 2. 77 0. 114 M2 L 16 2. 4-2. 7 2. 52 0. 106 W 14 2. 0-2. 3 2. 15 0. 076 W 16 1. 8-2. 2 2. 02 0. 091 L/W 14 1. 23-1. 40 1. 29 0. 048 L/W 16 1. 14-1. 39 1. 25 0. 076 ab 12 0. 5-1. 2 0. 85 0. 225 ab 15 0. 2-0. 5 0. 34 0. 074 pb 14 0. 3-0. 8 0. 58 0. 163 pb 15 0. 1-0. 4 0. 3 0. 086 ml 14 0. 5-0. 9 0. 68 0. 112 ml 16 0. 2-0. 6 0. 42 0. 098 pl 13 0. 5-1. 2 1. 02 0. 213 m3 L 11 2. 0-2. 4 2. 24 0. 121 M3 L 8 1. 9-2. 3 2. 06 0. 124 W 11 1. 6-1. 9 1. 75 0. 093 W 8 1. 6-1. 8 1. 75 0. 076 L/W 11 1. 22-1. 35 1. 28 0. 041 L/W 8 1. 06-1. 28 1. 18 0. 07 ab 7 0. 3-1. 0 0. 49 0. 248 pb 11 0. 3-0. 8 0. 48 0. 16 pb 7 0. 1-0. 4 0. 25 0. 096 ml 11 0. 2-1. 1 0. 48 0. 26 ml 7 0. 2-0. 4 0. 3 0. 058 Red Corral Pit D Measure N OR Mean SD Measure N OR Mean SD m1 L 13 2. 8-3. 5 3. 06 0. 18 M1 L 19 3. 0-3. 5 3. 25 0. 15 W 14 1. 7-2. 1 1. 89 0. 122 W 19 2. 1-2. 4 2. 25 0. 102 L/W 13 1. 48-1. 84 1. 63 0. 092 L/W 19 1. 25-1. 59 1. 45 0. 078 ab 13 0. 1-0. 7 0. 4 0. 188 ab 17 0. 1-0. 5 0. 32 0. 11 pb 13 0. 2-0. 75 0. 52 0. 187 pb 16 0. 1-0. 5 0. 29 0. 09 al 11 0. 2-1. 2 0. 75 0. 281 ml 13 0. 2-0. 7 0. 48 0. 168 ml 18 0. 2-0. 6 0. 44 0. 128 pl 13 0. 3-0. 9 0. 66 0. 187 m2 L 12 2. 5-2. 9 2. 67 0. 123 M2 L 14 2. 3-2. 8 2. 56 0. 128 W 13 2. 0-2. 1 2. 02 0. 038 W 14 1. 8-2. 1 2. 01 0. 073 L/W 12 1. 25-1. 45 1. 32 0. 058 L/W 14 1. 19-1. 40 1. 28 0. 055 ab 8 0. 5-1. 0 0. 6 0. 177 ab 8 0. 2-0. 5 0. 36 0. 098 pb 11 0. 2-0. 8 0. 49 0. 17 pb 9 0. 2-0. 6 0. 32 0. 13 ml 11 0. 2-0. 7 0. 49 0. 168 ml 11 0. 2-0. 5 0. 35 0. 104 pl 10 0. 7-1. 2 1 0. 156 m3 L 7 1. 9-2. 3 2. 13 0. 125 M3 L 8 1. 7-2. 0 1. 89 0. 136 W 7 1. 5-1. 8 1. 62 0. 122 W 8 1. 5-1. 8 1. 63 0. 128 L/W 7 1. 12-1. 47 1. 32 0. 127 L/W 8 1. 06-1. 25 1. 16 0. 068 ab 3 0. 1-0. 4 0. 3 0. 141 pb 7 0. 3-0. 5 0. 39 0. 084 pb 3 0. 0-0. 3 0. 1 0. 173 ml 6 0. 2-0. 5 0. 35 0. 122 ml 4 0. 15-0. 50 0. 26 0. 16 southwestern United States is better known, it seems prudent not to 0. Lingual jaw depth below m1 talonid = 20. 0. designate a new species for the Red Corral wood rat. The associated left and right dentaries, 4242 (Fig. 28A), are smaller than 4241 and are shorter, narrower, and less deep than those Order Carnivora of the paratype of Canis lepophagus from the Cita Canyon LF of Texas Family Canidae and of the modern coyote but are larger than the dentaries of the modern Canis lepophagus Johnston, 1938 red fox, Vulpes vulpes. All of the cheek teeth are present except for Figures 28A-B the posterior half of the left m2 and the peg-like left m3. The jaws Referred specimens. Pit B: F:AM 62987, mandible with right are broken anterior to the canines, but a few incisors were found in dentary possessing alveoli of p2-m2 and anterior portion of left dentary association. Measurements below were taken on the more complete possessing canine, p2, and alveoli of p3 and p4. Pit C: 4241, left dentary right mandible and closely match those given by Kurtén (1974, p. 31) fragment with alveolus of p3, broken p4, complete m1-m2, and alveolus for the same specimen. L p2 = 9. 0; W p2 = 3. 6; L p3 = 10. 4; W p3 = of m3; 4242, associated right and left dentaries; unnumbered incisors 3. 9; L p4 = 11. 9; W p4 = 5. 0; L m1 = 19. 2; W m1 = 7. 1; L m2 = 8. 8; and upper P4 carnassials. Pit D: 4107, left maxillary fragment with P2 W m2 = 6. 4; L of p2-p4 = 33. 5; L of m1-m3 = 31. 3; lingual jaw depth and alveoli of P1 and P3; 4108; left maxillary fragment with P3-M2; below m1 = 18. 7. 4208, isolated teeth; 4109, left calcaneum. Tedford et al. (2009, p. 113) mentioned the mandible, 62987, from Description. The left dentary, 4241 (Fig. 28B), is the size Pit B but did not provide measurements. The right dentary is more of that of Holocene Canis latrans Say. The crown of p4 is missing. complete and retains the condylar and angular processes, but the tip Measurements of m1 are: AP L = 22. 4; labial length of trigonid to notch of the coronoid process is missing, as are all of the teeth. The alveolar = 15. 8; maximum width across trigonid = 8. 6; width of talonid = 8. 2. length of p2-m3 is 72. 5. The labial jaw depth below the m1 alveolus is AP L of m2 = 10. 8; TW of m2 = 8. 0. Length of m1-m3 alveolus = 38. 21. 2. The left dentary retains p2 and the canine but is broken posterior 39

FIGURE 28. Canis lepophagus: A, left dentary, c, p1-m2, 4242, Pit C; B, left dentary, p4-m2, 4241, Pit C. Urocyon sp. : C, right m1, 4110, Pit D. Borophagus diversidens: D, canine, 4103, Pit D; E, left maxillary, M1, 4243, Pit C; F, right calcaneum, 4248, Pit C; G, left metacarpal IV, 4106, Pit D. Trigonictis cookii: H, left P4, 4112, Pit D; I, right femur, 4116, Pit D. Bassariscus sp. : J, right M2, 4198, Pit D. 40 to the m1 alveolus. The jaws appear to compare in size with most other fragment from the same locality. Akersten (1972, p. 19) referred to this jaws assigned to this species. species an edentulous dentary fragment from the Red Light LF (late In the left maxillary fragment, 4107, L P2 = 12. 2 and W P2 = 5. 0. Blancan), Hudspeth County, Texas. In the left maxillary fragment, 4108, P3 and P4 are broken and cannot Tedford et al. (2009, p. 72-73) described Urocyon galushai from be accurately measured. L M1 = 14. 0; W M1 = 17. 8; L M2 = 7. 5; W the 111 Ranch (Dry Mountain) locality (late Blancan), San Simon M2 = 12. 0. Valley, Graham County, Arizona, and referred to this species the Remarks. Hibbard (1941c) referred a small canid dentary, KU specimens mentioned above from Beck Ranch, Red Light, and Vallecito 4602, from Rexroad Locality 3 in Kansas to Canis lepophagus. His Creek as well as additional material from the Palm Springs Formation, measurements indicate an individual about the size of 4242. Kurtén San Diego County, California, and two hitherto unpublished teeth (a (1974, p. 31) gave measurements of 4241 and 4242 from Red Corral right M1 and a lower left canine) from the late Blancan Cita Canyon and stated (p. 5) that “The two specimens differ markedly in size but LF, Randall County, Texas. They also described U. citrinus from the since both are within the variation range of C. lepophagus, and the large Inglis site 1A (early Irvingtonian), Citrus County, Florida (Tedford specimen is much smaller than wolf-like forms such as C. texanus, both et al., 2009, p. 73-75). In addition, they stated (p. 72) that because of are here regarded as coyote. ”It should be noted that C. texanus was the fragmentary nature and questionable association of the material later transferred to the South American genus Protocyon by Kraglievich assigned to U. progressus, the species cannot be properly diagnosed (1952) and later to Xenocyon by Tedford et al. (2009). Nowak (1979) at the present time. They further stated (p. 73) that the M2 used by reviewed the species of Canis and concluded that all Blancan specimens Getz (1960, p. 363) to describe U. atwaterensis from the Borchers LF despite their variable size are referable to C. lepophagus. Tedford et al. (late Blancan), Meade County, Kansas, is not diagnostic, as this tooth (2009, p. 109) referred 3 teeth (UMMP 37132) from the early Blancan shows great variability in modern U. cinereoargenteus, and, therefore, Rexroad Locality 3 LF of Kansas to a slightly smaller species, C. the fossil species is a nomen vanum. ferox, but did not discuss Hibbard’s specimen, KU 4602. C. ferox was The Red Corral teeth cannot be adequately compared with Urocyon originally described by Miller and Carranza-Castañeda (1998) based on progressus as the m1 of that species is unknown and the weathering of a skull, mandible, and other material from a late Hemphillian locality the Red Corral M1 has obliterated some of the diagnostic features. The in Guanajuato, Mexico. Tedford et al. (2009) referred additional late paratype left M1 of U. progressus is an unworn tooth and is larger than Hemphillian as well as early Blancan specimens from Mexico and the the Red Corral tooth. Adequate comparison with the m1 and M1 in the United states to C. ferox. It is possible that KU 4602 may also be that of type of U. galushai is rendered difficult, as these teeth are broken. I C. ferox but more than likely Hibbard (1941c) was correct in assigning have not examined the m1 of U. citrinus but the tooth appears to have it to C. lepophagus. It also seems unlikely that there would be two a wider talonid than that of the Red Corral m1. Tedford et al. (2009, species of coyote in the Red Corral LF and, therefore, I follow Kurtén p. 210, appendix 3, table 5) give the measurements as L = 12. 0; W of (1974) and Novak (1979) in recognizing a wide range of variation in C. trigonid = 4. 0; W of talonid = 5. 0. lepophagus and assign both 4241 and 4242 to that species. Borophagus diversidens Cope, 1892 Urocyon sp. Figures 28D-G Figure 28C Referred specimens. Pit C: 4243, left maxillary fragment with Referred specimens. Pit D: 4110, right m1; 4111, left M1. M1; 4244, right M1; 4245, left M1; 4246, left upper canine; 4247, Description. A gray fox is represented in the fauna by two teeth isolated teeth including an incisor and two m3s; 4231, distal right that are inadequate for species identification. The right m1, 4110 (Fig. humerus; 4248, right calcaneum; 4249, partial metapodials. Pit D: 28C), measures 12. 8 long, 5. 1 wide across the trigonid and 4. 8 wide 4102, incisors; 4103, canine; 4104, canine; 4105, isolated molars and across the talonid. The protoconid is high. The metaconid is slightly premolars; 4106, left metacarpal IV. Wang et al. (1999, pp. 303-304) higher than the paraconid as in modern Urocyon cinereoargenteus, referred to this species several specimens collected from the fauna by but it is a prominent cone-shaped cusp distinctly separated from the parties from the Frick Laboratories and currently housed in the American paraconid. A small protostylid is appressed to the posterolateral surface Museum of Natural History. From near Pit A: F:AM 67334, right partial of the protoconid. This feature is frequently present in modern Urocyon ramus with p3-m2 all broken at bases. From Pit C: F:AM 67333, right but was absent in all Vulpes jaws examined. A low, narrow mesoconid partial ramus with c1 and p3 alveoli, p4-m1 and m2 alveolus, and right ridge connects the protoconid and hypoconid. A well-developed isolated m1; and F:AM 129871, left isolated worn m1. From Pit D: hypoconulid is situated posterior to the hypoconid. The lingual edge of F:AM 67364, left ramus with c1 alveolus, p2 alveolus-m2, m3 alveolus the talonid basin contains three small entoconulids. A narrow, medially (Wang et al., 1999, figs. 128A-B) and associated detached right canine; notched transverse cristid connects the hypoconid and the entoconid. F:AM 67365, crushed fragmentary skull with P4-M1 and isolated teeth The left M1, 4111, is slightly weathered and much of the including M2 and premolars; and F:AM 129870, left partial maxillary enamel is gone. The tooth dimensions are near the mean for Urocyon with P4 broken-M1. cinereoargenteus as given by Stevens (1965). The anteroposterior Description. Fossil specimens recovered from the fauna by the diameter is 8. 2 as measured along the external border, and the transverse author are quite fragmentary. Most of the teeth are broken or worn and diameter is 9. 9. The protocone, paraconule, hypocone, and metaconule do not yield useful measurements. The most complete specimen is a are worn; the paracone is higher than the metacone, and the distance left maxillary fragment, 4243 (Fig. 28E), containing the posterior root between the apices of these cusps is 4. 8. The external cingulum appears of P4 and a nearly complete but worn M1. The right M1, 4244, appears to be weak or absent, but this may be partially due to loss of enamel to represent the same individual. The canine, 4103 (Fig. 28G), is very through weathering. The anterior cingulum joins the paraconule ridge robust. Crown height is 26. 5, and the greatest diameter is 16. 9. between the paraconule and the paracone. The posterior cingulum Wang (written communication, 2015) graciously provided the extends well laterally and joins the metaconule ridge between the following measurements of the F:AM specimens: Pit C, 67333, L p4 = metaconule and the metacone. 21. 0, W p4 = 16. 3, L m1 = 33. 5, W m1 trigonid = 14. 7, W m1 talonid Remarks. Remains of the gray fox are quite rare and usually = 13. 1; Pit D, 67364, L p3 = 10. 4, L p4 = 21. 5, W p4 = 14. 8, L m1 = fragmentary in Blancan faunas of the Great Plains and western 32. 5, W m1trigonid = 15. 1; W m1 talonid = 13. 0, L m2 = 12. 8, Wm2 states. They are frequently assigned simply to Urocyon sp., as in the = 9. 0; Pit D, 67365, L P4 = 30. 0, L M1 = 17. 5. case of a left P4, a right P4, a left p2, and a left m2 from the early The distal portion of a right humerus, 4231, has had some Blancan Beck Ranch LF from Scurry County, Texas (Dalquest, 1978, restoration. The greatest width across the capitulum and medial p. 287), a possible record from the Broadwater LF of Nebraska, and condyle is approximately 63. The least anteroposterior diameter undescribed material from the Arroyo Seco (Blancan) and Vallecito of the articulating ulnar surface is 15. 7. Measurements of the right Creek (Irvingtonian) faunas of the Anza-Borrego region of California calcaneum, 4248 (Fig. 28F), are: greatest L = 54. 8; width across medial (Cassiliano, 1999). articular facet perpendicular to long axis = 25. 5; greatest posterior W Stevens (1965) described Urocyon progressus from Rexroad of calcaneal tuber = 19. 2. The left metacarpal IV, 4106 (Fig. 28G), Locality 3 (early Blancan), Meade County, Kansas. The holotype is a is complete and well-preserved. The proximal articular surface is left parietal. An incomplete left tibia and a left M1 were designated as convexly arched and articulates with the distal face of the unciform. The paratypes. Bjork (1974, p. 25) referred an edentulous fragmentary right proximal end contains lateral facets for articulation with metacarpals maxillary and jugal from the type locality to this species and Tedford III and V. The shaft is straight and nearly cylindrical in cross-section. et al. (2009, p. 71) tentatively referred a right partial maxilla with P1 The distal articular surface is smooth and convex cranially and sharply alveolus and P2-P4 which they figured (p. 70, figs. F-G) and a cranial keeled caudally. Measurements are: L = 78. 9; proximal AP L = 15. 5; 41 TABLE 12. Measurements (in mm) of P4 in Trigonictis species. Abbreviations: APL = anteroposterior length; Pr. W = protocone width; Pa. W. = paracone width * = measurements by Hibbard (1941b, 1941c); ** = measurements from Bjork (1970); *** = measurements by Ray et al (1981); other measurements by the author. Name Museum No. Faunal Loc. Side APL Pr. W. Pa. W. T. cookii WTAMU-V-4112 Red Corral D, TX Left 9. 6 5. 9 4. 7 T. cookii** UMMP V-49819 Hagerman, ID Right 9. 6 5. 7 4. 5 T. "idahoensis" USNM 23664 Hagerman, ID Left 11. 3 7. 1 5. 4 T. "idahoensis" UMMP V-49728 Hagerman, ID Left 11. 6 7 5. 4 T. "kansasensis" KU 4604 Rexroad Loc. 3, KS Left 11. 9 7. 8 6. 6 type* T. "kansasensis" UMMP V-51874 Rexroad Loc. 3, KS Right 10. 9 7. 1 5. 6 T. macrodon type*** ANSP 11626 Maryland Left 11. 6 7. 6 TABLE 13. Measurements (in mm) of m1 in Trigonictis species. Abbreviations: APL = anteroposterior length; Tg. L. = trigonid length; Tg. W. = trigonid width; Tl. W. = talonid width. * = measurements by Gazin (1934b); ** = measurements by Bjork (1970); *** = measurements by Hibbard (1941b, 1941 c); **** = measurements by Ray et al (1981); other measurenens by the author. NA = not available. Name Museum No. Faunal Loc. Side APL Tg. L. Tg. W. Tl. W. Red Corral D, T. cookii WTAMU-V-4113 TX Right 12. 1 8. 2 5. 2 5. 1 Bivins Pit 2, T. cookii F:AM 62740 TX Left 12. 2 8. 1 5. 1 4. 9 T. cookii type* USNM 12606 Hagerman, ID Right 10. 7 7. 2 4. 6 4. 5 T. cookii UMMP V-49819 Hagerman, ID Right 11. 6 7. 7 4. 8 4. 8 T. cookii UMMP V- 55514 Hagerman, ID Left 11. 6 7. 8 5. 1 4. 8 T. cookii** USNM 12608 Hagerman, ID Left 11. 7 NA 4. 9 NA T. cookii** USNM 25138 Hagerman, ID Left 11. 5 NA 5. 1 NA T. macrodon type**** ANSP 11626 Maryland Right 12. 2 >9. 0 5. 7 NA T. "idahoensis" type* USNM 12030 Hagerman, ID Left 14. 2 9. 9 6. 3 6 T. "kansasensis" Rexroad Loc. type*** KU 4604 3, KS Right 14. 8 10 6. 4 6 proximal W = 12. 7; mid-shaft W = 9. 6; distal condyle L = 14. 0; distal The right m1, 4113, is long and slender with a well-developed condyle W = 12. 9. and deeply notched carnassial blade. The trigonid is longer than the Remarks. Borophagus diversidens is a common species in talonid, and the metaconid is strongly developed and separated from Blancan faunas in the Great Plains and the southwest United States. the base of the protoconid by a shallow notch. The talonid is broad and basined with a prominent but worn hypoconid that is separated from the Family Mustelidae protoconid by a broad deep notch. The posterior border of the talonid Trigonictis cookii (Gazin, 1934b) slopes lingually. Measurements of m1 for Trigonictis cookii and other Figures 28H-I species of Trigonictis are given in Table 13. Note that the Red Corral Referred specimens. Pit D: 4112, left P4 in bone fragment; specimen is slightly larger than m1s of T. cookii from Idaho. 4113, right m1; 4114, right upper canine and left lower canine; 4115, Two canines, 4114, are referred to this species. The upper canine, edentulous left dentary; 4116, right femur; 4209, left femur; 4210, right 4114a, compares in size with that in a partial skeleton of Trigonictis metacarpal I. Bivins Pit 2: F:AM 62740, left dentary with c, p2, p3, p4 cookii, UMMP V 49819, from Hagerman, Idaho. The lower canine, alveolus, m1, and m2 alveolus. 4114b, is more slender and less robust than that of V 49819. Description. The left P4, 4112 (Fig. 28H) shows the typical An edentulous left dentary fragment, 4115, broken across the characteristics of Trigonictis upper carnassials. The tooth is elongate alveoli of p2 and m2, is tentatively referred to Trigonictis cookii. The and triangular in occlusal view and is strongly indented along the jaw is larger, longer and deeper than those of T. cookii from Hagerman, anterior border. A cingulum extends across the anterior border of the however. The alveolar length of p3-m1 is comparable to that in most tooth and continues posteriorly in a straight line from the protocone to T. “idahoensis” and the holotype of T. “kansasensis,” but the anterior the posterolingual base of the metacone. The protocone rises from the premolars were more crowded. The alveoli of the posterior root of p3 cingulum as a small but distinct cusp. An incipient hypocone is present and the anterior root of p4 are confluent as are the posterior root of p4 on the lingual cingulum opposite the paracone. The talon enclosed and the anterior root of m1. The alveolus of the posterior root of p2 is by the cingulum, protocone, hypocone, and paracone is basined. The posterolabial to that of the anterior root of p3. The jaw is not as deep as parastyle is merely a slight upward projection of the anterior cingulum. that of T. “idahoensis” or T. “kansasensis. ”Lingual jaw depth below A good shearing blade is formed by the ridge connecting the paracone m1 is 12. 0. and metacone. Measurements of P4 for T. cookii and other species of The right femur, 4116 (Fig. 28I), is complete and compares in Trigonictis are given in Table 12. size with the right femur, V 49819, of Trigonictis cookii from Idaho. Note: The Hagerman specimens originally described as T. The trochanteric fossa is deeply excavated, and the greater trochanter idahoensis and the Rexroad specimens originally described as T. extends down the lateral surface of the shaft to the level of the lesser kansasensis were synonymized with T. macrodon by Ray et al. (1981). trochanter. The left femur, 4209, is similar but slightly shorter and is TABLE 14. Measurements (in mm) of femurs in Trigonictis cookii missing part of the distal condyle. Comparative measurements of the from Hagerman LF, Idaho (Bjork,1970) and Red Corral Pit D. NA = three femora are given in Table 14. Measurements of the metacarpal, measurement not available. 4210, are L = 30. 2, proximal W = 7. 3, and distal W = 5. 7. Measurement V49819 WTAMU - WTAMU - The left dentary, F:AM 62740, is not part of the Red Corral Hagerman, ID V-4116 V-4209 LF but comes from the Bivins Pit 2 LF located in northern Oldham County about 11. 2 km (7 miles) south of Channing and about 14. 4 Length 67 71. 9 69 km (9 miles) east of Proctor Pit D. It is described here for comparison Proximal width 16. 9 18. 2 16. 9 purposes because it comes from sedimentary deposits exposed along Proximal depth NA NA NA Middle Cheyenne Creek that are of similar age, lithology and reddish Midshaft width 6. 3 6 5. 5 brown color as those at Proctor Pit D. The jaw is dark reddish brown Midshaft depth 5. 4 5. 7 5. 2 as are the fossils from Pit D. It is nearly complete, lacking only p4, m2 Distal width NA 15. 9 NA and the angular process. The length of c-m1 is 37. 0 and that of p2-m1 is Distal depth NA 13. 6 NA 42

FIGURE 29. Homotherium sp. : A, left dentary with 2 incisors, c, p4-m1, F:AM 144637, Pit B. Miracinonyx studeri: B, left dentary, c, p3-m1, F:AM 69255, Pit D. Taxidea sp. : C, left dentary, worn m1-m2, F:AM 62741, Pit B. Capromeryx sp. : D, left dentary, p2-m1, F:AM 117078, Pit D. Scale bar = 2 cm. for all specimens. 28. 0. The m1 is moderately worn; measurements as determined by the faunas in North America. Of these, the larger and better known is T. author are: L = 12. 2, maximum W = 5. 1, trigonid L = 8. 1, talonid W macrodon (Cope), which now includes in synonymy the formerly = 4. 9. The lingual jaw depth below m1 is 13. 0 and the jaw thickness is recognized species T. idahoensis (Gazin) and T. kansasensis Hibbard 6. 9. These measurements agree with those of Ray et al. (1981) except (see Ray et al., 1981). The smaller species, T. cookii (Gazin), is about for their m1 length (12. 3) and trigonid length (8. 4). two-thirds the size of T. macrodon and is known from the Hagerman Remarks. Two species of Trigonictis are known from Blancan (Gazin, 1934b, 1937; Zakrzewski, 1967; Bjork, 1970) and Grandview 43 (Shotwell, 1970) local faunas of Idaho; the Sand Draw (Skinner et al., the ascending ramus from the top of the coronoid process to the ventral 1972, p. 109, F:AM 49160) and Broadwater (Anderson, 1984) local border of the jaw is 42. 0. The width of the articular condyle is 18. 7. faunas of Nebraska; the 111 Ranch LF of Arizona (Galusha et al., 1984), Remarks. The Pit B dentary is similar in size to that of the modern and the Red Corral LF of Texas (Anderson, 1984). Its occurrence in badger, Taxidea taxus. Remains of Taxidea are known from many the Red Corral and Bivins Pit 2 local faunas is the first record of this Blancan local faunas including Rexroad Loc. 3 and Deer Park (Kansas); species from the southern Great Plains. Zakrzewski (1967) showed Broadwater and Sand Draw (Nebraska); Hagerman (Idaho);White that, although there is some overlap in size between the two species, Bluffs(Washington); Red Light, Beck Ranch, and Cita Canyon (Texas); T. cookii is a distinct species rather than a female of T. idahoensis (= Buckhorn (Morgan et al., 1997) and Tonuco Mountain (Morgan et T. macrodon). al.,1998) of New Mexico; as well as Anita, Bear Springs, Country The lengths of the Red Corral m1 (12. 1) and the Bivins Pit 2 Club, and San Simon of Arizona (Morgan and White, 2005), but the m1 (12. 2) are slightly greater than those of the Idaho specimens of genus is typically represented by only one or two specimens at a given Trigonictis cookii and, in fact, fall within the gap (11. 7-12. 6) used by locality. In the case of the Red Corral specimen, loss of the anterior and Bjork (1970) to separate the Hagerman specimens of T. cookii and T. ventral portion of the dentary due to breakage plus the heavily worn idahoensis first described by Gazin (1934b). However, the m1 length in condition of the molars prevent adequate comparison with the dentary the holotype of T. macrodon (ANSP 11626) from Maryland is 12. 2 and of the modern badger. the minimum m1 length for any specimen assigned by Ray et al. (1981) to T. macrodon is 12. 0. Jaws containing similar-sized carnassials were Family Procyonidae reported from the White Bluffs LF, Washington (Gustafson, 1978) and Bassariscus sp. the Sand Draw LF, Nebraska (Skinner et al., 1972, p. 109, F:AM 49163) Figure 28J as T. cookii. Using other variates, however, Ray et al. (1981) reassigned Referred specimen. Pit D: 4198, right M2. these specimens to T. macrodon. They also assigned the Bivins Pit 2 Description. The tooth (Fig. 28J) is small and triangular in shape specimen to T. macrodon. However, the very diagnostic P4 and the with well-developed protocone, paracone, and metacone – the paracone femora from Red Corral compare easily in size with those of T. cookii being slightly better-developed than the metacone. A small protoconule (UMMP V49819) from Idaho and are considerably smaller than those is present on the ridge connecting the protocone with the paracone. of T. macrodon. The length of m1 and the small edentulous dentary The hypocone and posterolingual cingulum are lacking. The size and from Red Corral closely match those measurements of the Bivins Pit cusp arrangement is similar to that observed in M2 of a modern skull 2 specimen. I, therefore, assign both the Red Corral and Bivins Pit of Bassariscus astutus, the ring-tail, examined by the author, except 2 specimens to T. cookii pending the discovery of more specimens that the latter possesses a small hypocone and posterolingual cingulum that might better delineate the range of variation within and the size making the tooth a bit wider than the fossil. According to Baskin differences between the two species. (written communication, 2014), there is variation in the presence/ Taxidea sp. absence of a hypocone in specimens that he has seen. The fossil tooth is Fig. 29C 3-rooted. Measurements of the fossil are: anteroposterior length across paracone-metacone = 3. 1; transverse width across protocone-paracone Referred specimen. Pit B: F:AM 62741, a left dentary with the = 4. 4 and across protocone-metacone = 4. 2. root of p3, the alveolus of p4, and very worn m1-m2. Remarks. Czaplewski (1990, p. 34) described and figured a left Description. The dentary (Fig. 29C) is that of an old individual. M2 of Bassariscus sp. from the early Blancan Verde LF of Arizona. He It is broken anterior to p3 and beneath the entire tooth row. The first gave the anteroposterior length as 3. 19 and the transverse width as 4. 41. and second molars are worn very flat. Length and width of m1 are 14. He stated that “as in modern species of Bassariscus, the Verde M2 has 4 and 7. 6, respectively. The ascending ramus and articular condyle are all cingula greatly reduced. The paracone and metacone are sub equal well preserved, although a portion of the tip of the coronoid process in size, with the paracone being slightly larger. No parastyle is present. has been restored, making the process appear more rounded than the A faint protoconule and faint metaconule are present, but are much more pointed process seen in recent Taxidea. The maximum height of reduced and discernable only as slight swellings on the preprotocrista and postprotocrista, respectively. The internal cingulum is restricted to TABLE 15. Measurements (in mm) of mandibles and lower dentitions the posterolingual corner of the tooth and lacks a hypocone. ” of Miracinonyx studeri from Cita Canyon LF, Texas (WT 1218); Fossil Bassariscus species are described mainly on the basis of Red Corral Pit C (WT 4223); Red Corral Pit D (F:AM 69255); and lower teeth and jaws. Few upper dentitions are known and the Verde Guanajuato, Mexico (IGM 6676). and Red Corral M2s are, apparently, the first fossil M2s to be described. Measurement WT WT F:AM IGM 6676 The only known Blancan species of the genus is Bassariscus casei 1218 4223 69255 from the Rexroad 3 LF (Hibbard, 1952b). It is represented by a right Length, ant. of symphysis to post. 172. 9 dentary and a left maxillary fragment containing the posterior part of of condyle P3, P4, M1, and the alveolus of M2, so that a comparison with the Depth of jaw below anterior of p4 30 32 39. 5 ~22 Red Corral tooth is not possible. Hibbard stated that the fossil species is distinguished from the Holocene species by its narrower lower Depth of jaw below posterior of m1 28. 2 31. 2 38. 2 TABLE 16. Measurements (in mm) of femora of Miracinonyx studeri Thickness of jaw at posterior of m1 15. 4 15. 5 15. 7 15. 0 at p4 from Red Corral Pit C (RC 4235) and modern Panthera leo (M-874) from Univ. Texas collection. Measurements are those used by Merriam c-m1 inclusive 82. 6 94. 5 78. 3 and Stock (1932, p. 137-138). NA = not available. p3-m1 inclusive 55 57. 2 60. 5 47. 9 Measurement (Merriam and Stock, 1932) RC 4235 RC 4235 Lion c length at enamel base 13. 2 19. 4 right left M-874 Greatest length 343 342 320 c width at enamel base 11. 1 13. 5 Transverse diameter of proximal end NA NA 78 c-p3 diastema 12. 5 15. 2 15. 4 Greatest anteroposterior diameter of head 33. 2 33. 2 35. 2 p3 length 15. 2 14. 2 16. 5 13. 4 Transverse diameter of shaft at middle NA 26 26. 1 p3 width 8. 6 9. 4 10. 5 7. 1 Anteroposterior diameter of shaft at middle 28. 9 31. 5 23. 3 p4 length 18. 8 19. 9 19. 5 17. 6 Greatest width across the distal extremity 64. 2 NA 62. 7 p4 width 9. 4 10. 3 10. 7 7. 5 Greatest anteroposterior dia. of distal extremity 66. 5 NA 67 m1 length 22. 6 21. 8 23. 5 19. 6 Greatest width of rotular surface 32. 4 32. 4 33 m1 width 10. 7 10. 9 11 7. 9 Greatest width of intercondylar notch 18. 5 NA 17. 8 Length of anterior blade of m1 10 10. 9 10 Greatest width of articular surface of inner condyle 25. 2 NA 23. 7 Length of posterior blade of m1 13. 3 11 12. 2 44

FIGURE 30. Miracinonyx studeri: A, left P3, 4225; B, right maxillary, P3-P4, 4224; C, right dentary, p3-m1, 4223. All specimens are from Pit C. premolars and molars; by the more open valleys between the cusps; and m1 fragment. by the well-developed internal cingulum of P4. B. casei is also reported, Description. The dentary (Fig. 29A) is badly weathered and but not described,from the early Blancan Beck Ranch LF from Texas on fractured and is broken below the canine and posterior to m1. The the basis of two dentaries and isolated upper and lower teeth (Dalquest, incisors are massive. Much of the canine is missing. The p3 alveolus 1978). The author has not had an opportunity to examine this material. shows that the two roots were fused; alveolar length and width are 10. The Red Corral specimen is not identifiable to species. 3 and 5. 5 respectively. The p4 and m1 are slightly worn; the p4-m1 length is 51. 8. The p4 has a prominent posterior accessory cusp; the Family Felidae tooth is 22. 0 long and 10. 3 wide. The m1 possesses an external shear Homotherium sp. facet; L m1 = 29. 0; W of anterior blade = 13. 0; W of posterior blade = Fig. 29A 12. 6. The canine-p3 diastema is approximately 38. 7. The lingual jaw Referred specimens. Pit B: F:AM 144637, anterior part of left depth below p3 is 37. 2 and below m1 is 37. 9. The mental foramen is dentary with two incisors, canine, p3 alveolus, p4 and m1. Pit D: 4099, situated below the p3-p4 contact. 45

FIGURE 31. Miracinonyx studeri: A, left calcaneum, 4238; B, left astragalus, 4239; C, right femur, 4234. All specimens are from Pit C.

Miracinonyx studeri (Savage, 1960) Description. Some of the fossil cat remains recovered from Pit C, Figures 29B; 30A-C; 31A-C; 32A-D; 33A-B especially the maxillary and mandibular dentitions, compare favorably with those of Miracinonyx studeri from the Cita Canyon LF described Referred specimens. Pit C: 4223, right dentary with p3-m1; 4224, by Savage (1960; as Felis studeri). Some of the postcranial elements right maxillary with P3-P4; 4225, left maxillary fragment with P3; also approach in size and morphology some of the larger elements 4226, left dentary fragment with m1; 4227, basicranium; 4228, right in the Cita Canyon collection, which may be referable to M. studeri. posterior skull fragment; 4229, atlas; 4230, cervical vertebra; 4232, Because there are several cat species represented in the Cita Canyon proximal right radius; 4233, distal left fibula; 4234, right femur; 4235, LF, referral of the larger postcranial elements to this species is still left femur; 4236, distal right tibia; 4237, distal left tibia; 4238, left somewhat tentative. calcaneum; 4239, left astragalus; 4240, metapodials including left mc The upper dentition is best represented by a right maxillary II, right mc III, distal left mc III, left mc IV, left mc V, left mt II, distal fragment, 4224 (Fig. 30B), containing P3 and P4 and the single-rooted right mt III, right mt IV, distal left mt IV,left mt V, and right mt V; 4486, alveolus of P2. A well-developed shear facet is present on the inner 7th cervical; 4487, lumbar vertebra; 4488, lumbar vertebra; 4489, left scapho-lunar; 4490, right navicular; 4491, right ectocuneiform; 4492, surfaces of P3 and P4. The central cusp of P3 is prominent, and there first phalanx; 4101, broken first phalanx; 4493, second phalanx; 4494, is a well-developed accessory cusp in line between it and the posterior second phalanx; 4495, third phalanx (claw); 4496, right cuboid. Pit D: cusp. A tiny lingual accessory cusp is present between the central cusp F. AM 69255, a nearly complete left dentary with canine and p3-m1. and the anterior cusp. The protocone of P4 is low – partly the result of shear. A prominent parastyle is present and the paracone and metacone 46

FIGURE 32. Miracinonyx studeri: A, left metacarpal II, 4240a; B, right metacarpal III, 4240b; C,left metacarpal IV, 4240c; D, left metacarpal V, 4240d. All specimens are from Pit C. 47

FIGURE 33. Miracinonyx studeri: A, left metatarsal II, 4240e; B, right metatarsal V, 4240f. Both specimens are from Pit C. 48 TABLE 17. Measurements (in mm) of metacarpals (Mc) and metatarsals Element Measurement RC 4240 M-874 M-916 (Mt) of Miracinonyx studeri from Red Corral Pit C (RC 4240, L=left, R=right), and modern Panthera leo (M-874 right and M-916 left). Mt II Greatest length 125. 1-L 112. 9 119. 7 Element Measurement RC 4240 M-874 M-916 Greatest prox. Mc II Greatest length 95. 7-L 99 102. 8 transverse width 20. 2-L 13. 7 18. 4 Greatest prox. Greatest prox. 26. 4-L 24. 3 27. 8 transverse width 16. 8-L 20 23 dorso-ventral ht. Greatest prox. Mid-shaft 13. 2-L 10. 7 13. 4 dorsoventral ht. 24. 3-L 23 28. 4 transverse dia. Mid-shaft Mid-shaft dorso- 13. 7-L 12 12. 1 transverse dia. 10. 5-L 9. 7 10. 8 ventral dia. Mid-shaft dorso- Greatest distal 21. 3-L 17. 1 21. 1 ventral dia. 12. 5-L 11. 3 12. 6 transverse width Greatest distal transverse width 16. 0-L 17 21 Mt IV Greatest length brk. -R 125. 1 130. 5 Greatest prox. Mc III Greatest length 115. 7-R 110. 5 112. 4 transverse width 14. 7-R 17. 6 19. 3 Greatest prox. Greatest prox. 26. 0-R 21. 7 25 transverse width 20. 4-R 22. 2 26. 2 dorso-ventral ht. Greatest prox. Mid-shaft 14. 6-R 13. 5 13. 6 dorso-ventral ht. 20. 2-R 20. 2 23. 4 transverse dia. Mid-shaft Mid-shaft dorso- 15. 3-R 11. 8 14. 6 transverse dia. 13. 1-R 11 12. 9 ventral dia. Mid-shaft dorso- Greatest distal 19. 7-R 16. 5 20 ventral dia. ` 12. 8-R 9. 7 10. 3 transverse width Greatest distal transverse width 19. 2-R 18. 8 21. 9 Mt V Greatest length 125. 2-R 112. 2 117. 8 Greatest prox. Mc IV Greatest length 109. 6-L 105. 7 109. 5 transverse width 18. 2-R 18. 5 22. 2 Greatest prox. Greatest prox. 13. 6-R 14. 5 17 transverse width 16. 2-L 17. 5 21. 3 dorso-ventral ht. Greatest prox. Mid-shaft 9. 2-R 8. 1 10. 6 dorso-ventral ht. 20. 1-L 20 23. 1 transverse dia. Mid-shaft Mid-shaft dorso- 10. 8-R 10. 4 10. 5 transverse dia. 12. 0-L 11. 4 13. 1 ventral dia. Mid-shaft dorso- Greatest distal 17. 0-R 15 19. 2 ventral dia. 12. 3-L 9. 5 10. 5 transverse width Greatest distal transverse width 17. 5-L 16. 6 20. 3 central cusp of p3 is worn flat, a heel is present, and the two roots are exposed in the jaw. The p4 possesses a tall central cusp, a low anterior cusp, and a prominent accessory cusp between the central and posterior cusps. The m1 shows a heavy labial shear facet and a wide, V-shaped Mc V Greatest length 101. 2-L 86. 4 90. 5 carnassial notch between the paraconid and protoconid. Measurements Greatest prox. are given in Table 15. The ramal fossa is deep and terminates anteriorly transverse width 22. 8-L 22. 4 24. 9 behind m1. The anterior part of the jaw preserves part of the diastema Greatest prox. between p3 and the canine, although the canine and alveolus are missing. dorso-ventral ht. 22. 0-L 20. 5 23 Below the diastema are two dorsoventrally aligned anterior lateral Mid-shaft mental foramina that appear to be nearly confluent because the bony transverse dia. 12. 2-L 11 13. 3 bar between them has been broken. A large posterior mental foramen Mid-shaft dorso- is situated about 10 behind the anterior pair. This foramen pattern is ventral dia. 11. 6-L 9. 9 10. 6 considered to be the most common one in pumas according to Savage Greatest distal (1960, p. 331-332). In addition, there is a large mandibular foramen transverse width 19. 2-L 16. 5 19. 6 situated about 25 behind m1 on the lingual jaw surface. There is also a left dentary fragment, 4226, which contains a broken and weathered m1. Savage (1960, p. 328) provided measurements of a mandible are both well-developed and separated by an open carnassial notch. and lower dentition of Miracinonyx studeri, WT 1218, housed in the Measurements are: P2 alveolus (L = 5. 0, W = 3. 5); P3 (L = 19. 0, W Panhandle-Plains Historical Museum. These measurements as well as = 10. 2); P4 (L = 28. 0, W across protocone and parastyle = 13. 5, W additional ones made by the author are shown in Table 15. across metacone = 8. 1). The length of P3-P4 is 48. 0. A left maxillary The left dentary, F:AM 69255 (Fig. 29B), from Pit D, is that of a fragment, 4225 (Fig. 30A), contains P3, the single-rooted alveolus young adult and is nearly complete with c, p3-m1. Part of the ventral of P2, and the posterior portion of the canine alveolus which shows portion below p4 and m1 was missing and has been restored. The that the canine was conical in shape (not mediolaterally flattened as articular condyle is present, but part of the angular process is missing. in Dinofelis paleoonca). The left P3 (L = 19. 5, W = 11. 1) resembles The ascending ramus is intact. The cheek teeth are only slightly worn. the right P3 in stage of wear and cusp development. Length and width The specimen is the size of 4223 from Pit C. Measurements are given measurements of two upper dentitions of M. studeri from Cita Canyon in Table 15. given by Savage (1960, p. 324) are: P3 (19. 1 x 9. 5 and 18. 2 x 9. 5); Postcranial elements are represented by a few vertebrae, leg bones P4 (28. 5 x 13. 9 and 27. 3 x 12. 6). and foot bones from Pit C. There is no duplication of elements and The lower dentition is represented by two dentaries. A right dentary, presumably all of the specimens are from one individual. 4223 (Fig. 30C), from Pit C is that of an old individual. It contains p3- An atlas, 4229, is nearly complete except for the missing wings. m1 and is broken across the base of the coronoid process. Most of the The atlantal foramen is well-developed. Width of the occipital condylar articular condyle is present, but the angular process is missing. The 49 fossa is 58. 0; W across the axis facets is 51. 0; and W of the neural of a smaller left astragalus, JWT 1683, from Cita Canyon are: greatest canal is 27. 5. length = 42. 0; greatest width = 36. 0; and width across the trochleae A right radius, 4232, is missing the distal half. The long diameter of = 25. 0. the proximal end is 30. 7 and the shortest diameter is 22. 3. At the broken Four complete metacarpals and four complete metatarsals, 4240 end, the shaft measures 26. 1 x 12. 6. The radial (bicipital) tuberosity is (Figs. 32, 33), were recovered and were compared with those of a prominent knob. The lateral tubercle below the proximal end is well- Panthera leo, M-874 and M-916 (Table 17). In the left metacarpal developed as a linear ridge. Length and width of an unnumbered right II, the trapezoid facet, Td, is triangular in shape as in the lion but is radius from Cita Canyon are 31. 0 and 22. 0 at the proximal end. narrower. The dorsointernal corner of Td is elevated above the rest of A left femur, 4235, and a right femur, 4234 (Fig. 31C), are nearly the facet but not as much as in the lion. The radial artery groove on the complete. They were compared with the femora of a modern lion, dorsal surface below the proximal end is slightly less developed than Panthera leo, skeleton, M-874, from the collections at the University of in the lion. The swelling on the dorsointernal border below the groove Texas in Austin (Table 16). The Red Corral femora are slightly longer is about as developed as in the lion. The trapezium facet, Tm, projects and more anteriorly bowed and the shaft is thicker anteroposteriorly. slightly above the proximal border and is not as well-developed as in In the lion, the shaft is slender but broadens slightly from the mid- the lion, and it is not as distinctly separated from the tubercle below. point to the proximal end but not toward the distal end. A linear muscle The dorsal facet for metacarpal III is elongated obliquely as in the lion. attachment ridge is present on the proximal lateral surface of both the The mid-shaft is not as inwardly bowed on its inner surface as in the Red Corral specimens and the lion. In the Red Corral femora this ridge lion. The distal ends are similar. continues distally and curves more anteriorly on the lateral surface In the right metacarpal III, the dorsoexternal border of the magnum whereas in the lion it disappears distally. The intercondylar notch is facet, Mg, is more raised than in the lion. Along the lateral border of shallow and broad on the patellar surface in the Red Corral specimens the proximal end, Mg is more sharply separated from a lateral facet for but deeper, narrower, and sharply defined distally in the lion. In the the unciform than in the lion. The dorsal metacarpal II facet is slightly Red Corral specimens, the neck connecting the head of the femur to more longitudinal in dorsal view and not as internally extended as in the the shaft appears to be shorter than in the lion. The left femur from lion. Therefore, the groove between the dorsal and palmar metacarpal II Pit C matches in size a large left femur, JWT 569, in the Cita Canyon facets appears broader and not as deep in the Red Corral specimen. In collection. Unfortunately, the proximal end of the latter is missing so lateral view, however, the long axis of the dorsal metacarpal II facet is that the overall length cannot be determined. However, the shaft appears oblique as in the lion. The unciform facet, Un, in the fossil is larger and to be of equal length and diameter (c. 26. 0), and the width across the broader (absent in Panthera atrox). In lateral view, the shaft is thicker distal extremity is 64. 0. Other femora in the Cita Canyon collection are in dorso-palmar direction than in the lion; the distal ends are similar. smaller. Table 16 compares the measurements of the Red Corral femora In the left metacarpal IV, the proximal end is similar to that of with those of the modern lion, P. leo. Panthera atrox. The palmar border is about as broad as in P. leo. The A right tibia, 4236, contains the distal end and most of the shaft inner border of the proximal end is not as deeply notched as in P. leo. but is missing the proximal end. A prominent ridge separates the The outer border of the surface articulating with the unciform is straight posterior surface from the outer lateral surface of the shaft (as in the and curves into the palmar border as in the modern lion. On the dorsal lion). At the distal extremity the grooves for the tendons of the flexor border, the indentation between the unciform facet and the metacarpal longus digitorum and tibial posticus muscles are well-defined (also as III facet is about as deep as in P. leo (shallower than in P. atrox). The in the lion). In the lion tibia a prominent tubercle lies anteromedial to dorsal mc III facet is similar to that of P. atrox. On the outer surface of these grooves, and another lies posterior to these grooves. The same the proximal end, the mc V facet is continuous from the dorsal to the tubercles are present on the Red Corral tibia but the anteromedial one palmar surface as in P. leo. is not as prominent. The notch incising the anterior border of the distal The left metacarpal V is longer than that of Panthera leo. The surface is not as deep in the Red Corral specimen as in the lion tibia. proximal surface articulating with the unciform is relatively broader Measurements of 4236 are: transverse diameter of the shaft at the near the dorsal border than in the modern lion, whereas in the latter, middle = 28. 2; greatest transverse diameter of the distal end = 49. 3; it tapers dorsally to appear as a narrow triangle. The inner ear-shaped and greatest anteroposterior diameter of the distal end = 31. 0. A right projection of the proximal end, which supports a portion of the tibia, JWT 1031, from Cita Canyon matches the Red Corral specimen articulating surface for mc IV, is longer but less extended laterally in size and features. The distal end measures 46. 0 by 29. 0. The distal compared to the lion. To the palmar side of this projection, the notch half of a fibula, 4233, from Pit C measures 27. 4 x 13. 0 across the that indents the margin of the facet for mc IV is slightly deeper than in extremity. the lion. On the outer side of the proximal end, the tuberosity is very A left calcaneum, 4238 (Fig. 31A), was compared with that of the pronounced, as in mature P. leo. The shaft is less bowed than in the lion. It measures 105. 5 in length (lion = 102. 6). The greatest width modern lion. Measurements of the Red Corral metacarpals and those of across the astragalar facets As1 and As2 at the peroneal tubercle is P. leo are given below in Table 17. 36. 8. The cuboid facet has been restored on its inner border, and its The left metatarsal II is not as inwardly bowed, and the greatest width measured from astragalar facet As3 to the outer side mesocuneiform facet is transversely narrower and more elongated is approximately 27. 8. The greatest depth of the outer face of the compared to the lion. The right metatarsal IV is missing the mid portion calcaneum measured normal to the plantar border and to the edge of the of the shaft. The proximal surface for articulation with the cuboid is outer astragalar facet is 41. 0. As2 and As3 are separate – bridged by narrower but less indented externally near the palmar margin compared a narrow ridge or crest in the lion but in the Red Corral cat, this ridge to Panthera leo. It is more rectangular in shape front to back, whereas is missing. In both the lion and the Red Corral cat, As1 encroaches in the modern lion, it is broader dorsally and narrower at the palmar posteriorly on to the dorsal surface of the tuber calcis. In the lion, a border. The left metatarsal V is missing the tip of the proximal end, but short, wide tuberosity occurs dorsally on the lateral surface behind the the right metatarsal V is complete. It is considerably longer than that of cuboid facet (AP = 15. 2, vertical height = 8. 8). This feature is not P. leo. The shaft is narrow as in the lion and about as bowed. The mt developed in the Red Corral specimen, although a stout lateral ridge IV ventral facet is not as well-developed as in the lion, and the lateral connects the cuboid facet with As1. In the Red Corral specimen, the border of the proximal surface is more raised. Measurements of the Red tuber calcis is longer than in the lion but the Achilles end is not as Corral metatarsals and those of P. leo are given in Table 17. wide. Achilles height and width are 26. 7 and 27. 7 in the lion and 25. Several complete metacarpals and metatarsals from Cita Canyon 1and 23. 5 in the Red Corral specimen. Measurements of a smaller left were examined. They are from 7 to 10 shorter than the corresponding calcaneum, JWT 1940, from Cita Canyon are: greatest length = 96. 0; ones from Red Corral. Some are slightly wider and heavier than their greatest width across the astragalar facets = 34. 0; greatest depth = 39. counterparts, but a few are slightly narrower. One left metatarsal V is 0; Achilles height and width of the tuber calcis are 23. 0 and 23. 0. actually larger and heavier than its counterpart from Red Corral. A left astragalus, 4239 (Fig. 31B), appears to articulate well with Remarks. Carranza-Castañeda and Miller (1996) referred a skull the calcaneum. The greatest length is 48. 0, the greatest width is 40. 0, rostrum and mandible and several teeth from the Blancan age (~3. 6 and the width across the trochlea is 28. 0. The greatest diameter of the Ma) Rancho Viejo site, Guanajuato, Mexico, to the species studeri but navicular head is 28. 0 and the minimum distance across the neck is 16. assigned it to the genus Felis. Measurements of the mandible, IGM 5. The neck is narrower in the lion and the navicular head is slightly 6676, are given in Table 15. They noted that the taxonomic status of this smaller. The trochlear surfaces are similar in the lion and the Red species has changed several times in recent years. It was synonymized Corral specimen, and the medial surface of the inner trochlear ridge with Miracinonyx inexpectatus by Van Valkenburgh et al. (1990). is interrupted in the middle by a muscle scar in both. Measurements They gave a brief taxonomic history of cheetah-like cats from North 50 America thus following Kurtén (1976) in resurrecting Cope’s (1895) named by Leidy from the “Loup Fork” of Nebraska, is considered by species, “inexpectata. ”Savage (1960), however, considered Felis Lucas et al. (2011) to encompass most known Stegomastodon specimens inexpectata (Cope) to be a nomen dubium because the type, an isolated from late Blancan faunas whereas S. primitivus is characteristic of early upper canine and P4 and jaw fragments with broken p4 and m1, from Blancan faunas. They note that S. mirificus has cheek teeth that wear to the Irvingtonian age Port Kennedy Cave in Pennsylvania, does not double trefoils, second molars with rudimentary fourth lophs/lophids, represent sufficient material upon which to properly designate a species. and third molars with 6-7 lophs/lophids. The left m3, 4505, is assigned Carranza-Castañeda and Miller (1996) also noted that a major problem to S. mirificus based on the presence of 6 lophids and the more complex in identification is that a lineage of pumas in North America paralleled trefoiling, thus providing a good indicator for the late Blancan age of the Old World cheetahs morphologically (Martin et al., 1977). They the Red Corral LF. noted also that the specimens assigned to Miracinonyx inexpectatus by Based on the results of Carbon 13 isotope studies of tooth enamel Van Valkenburgh et al. (1990) are from Hamilton Cave, West Virginia, in Stegomastodon from the Pleistocene of South America (e. g. Prado which dates about 0. 82-0. 85 Ma., and that it seems unlikely that a et al., 2001; Sanchez et al., 2003; Lopes et al., 2013), one might single species of felid would have a chronologic range of nearly three reasonably conclude that S. mirificus was probably a mixed feeder (C3 million years. Miracinonyx has been identified from several other browse and C4 grasses). Irvingtonian sites and was also listed as present in the Blancan age fauna from 111 Ranch, Arizona (White and Morgan, 2005). Order Perissodactyla No doubt the taxonomic status of this felid will continue to Family Equidae be debated. For now I retain the species studeri but assign it to the Nannippus peninsulatus (Cope, 1885) currently recognized genus Miracinonyx. In any event, the importance Figures 34H-I of the Red Corral felid is that it provides an association of dental and Referred specimens. Pit C: 4264, upper right molar; 4265, three postcranial elements of one individual from the same quarry site, as upper left molars; 4266, four upper tooth fragments; 4267, incisors; there is no duplication of elements. It demonstrates that this cat had 4268, isolated lower teeth; UMMP 50254, upper right molar. Pit D: long, relatively slender femora and large, stout metapodials. 4172, four upper molars; 4173, seven lower molars/premolars including Felis sp. – small three that are associated; 4174, incisors; 4175, right calcaneum; 4176, carpals and tarsals; 4200, two second phalanges. WT Loc. 5, draw west Referred specimens. Pit C: 4508, proximal left metacarpal IV. of Pit D: 4548, two lower right molars. Additional unstudied material is Pit D: 4100, upper right canine fragment; 4101, a phalanx. WT Loc. 5, in the Frick Collection. draw west of Pit D: 4547, proximal left metacarpal IV. Description. This small horse (much smaller than Equus) is not Description. The metacarpals are too small to belong to abundant in the fauna and is represented primarily by upper and lower Miracinonyx studeri but are about the size of a large mountain lion. They molars and premolars. No jaw material was found. Slightly worn upper might belong to the Blancan species Felis lacustris or F. rexroadensis molars are very hypsodont (Fig. 34H-I). In the lower cheek teeth, the which are tentatively retained in the genus Felis (sensu lato) because metaconid and metastylid are rounded loops. Measurements are given of the usual limitations of scarce and fragmentary fossil material that in Table 18. precludes assignment to one of the currently recognized cat genera. The A small right calcaneum, 4175, of an immature individual lacks proximal width of 4508 is 12. 6 and that of 4547 is 12. 6. The proximal the posterior epiphysis. The overall length would be in excess of 67. depth of 4508 is 14. 2 and that of 4547 is 14. 8. The canine fragment is The width across the astragalar facet is 31. 5, and the greatest anterior not diagnostic. height is 35. 4. Measurements, respectively, of two medial phalanges, Order Proboscidea 4200, are: length = 31. 1 and 28. 2; proximal width = 24. 9 and 23. 5; Family Gomphotheriidae proximal depth = 18. 5 and 18. 5; distal width = 22. 0 and 22. 5; distal Stegomastodon mirificus (Leidy, 1858) depth = 13. 2 and 13. 0. Remarks. Nannippus peninsulatus is one of the most characteristic Referred specimens. Pit C: 4505, left m3; 4506, small juvenile Blancan mammals. It is known from the late Blancan of Florida and tusk; F:AM 103209, a partial skull, jaws, and tusks. from numerous early and late Blancan faunas in Arizona, New Mexico, Description. The left m3, 4505, measures about 220 long and Texas; a few localities in Kansas; and a single tooth from the and about 88 wide and is that of a late mature adult. There are six Sand Draw LF of Nebraska. Some of the more notable occurrences lophids, and all show wear but not sufficient to obliterate trefoiling. cited by Morgan et al. (2008, p. 160-161) include the early Blancan The anterior part of the tooth contains several fractures and breaks, Bear Springs, Benson, Clarkdale, and Duncan local faunas and the and much of the enamel is missing on the inner and outer sides of the late Blancan 111 Ranch and Wolf Ranch local faunas of Arizona; the protolophid and metalophid and on the outer sides of the remaining early Blancan Buckhorn, Williamsburg, and Tonuco Mountain local lophids except the fifth, on which the enamel loop is complete. The faunas and the late Blancan Pearson Mesa, Anapra, Palomas Creek, and remaining central part of the protolophid shows complex or compound Santo Domingo local faunas of New Mexico; and the late Blancan Cita trefoiling (ptychodonty). The metalophid has a compound entofoil. Canyon, Hudspeth, Red Light, and Mount Blanco local faunas of Texas. The remaining lophids have simple entofoils and compound ectofoils Most Blancan records are from strata that date to the upper Gauss chron where the enamel is preserved. There is a small hypoconulid on which or older (older than 2. 58 Ma). The only well-documented late Blancan the enamel is missing. A small conulid is present between the trilophid records of Nannippus younger than the Gauss/Matuyama boundary and the tetartolophid. The anterior root is large and single, although the (2. 58 Ma) are Mount Blanco, Texas, and the Macasphalt Shell Pit in ventral part of the outer side has been broken and displaced. The tooth Florida, both of which are in reversely magnetized sediments of the is slightly concave on the dorsal surface. early Matuyama chron (2. 16-2. 58 Ma) (Bell et al., 2004; Morgan et The skull and jaws, F:AM 103209, are large and contained within al., 2008). N. peninsulatus apparently became extinct sometime during a partially opened jacket. Cheek teeth are present. Because of its large this interval. size and lack of preparation, the specimen was not borrowed for study. Stable Carbon 13 isotope studies of tooth enamel of Nannippus Remarks. The left m3 appears to be that of Stegomastodon from the late Blancan of Florida indicate a grazing diet with a mirificus, the most common Blancan species in the Great Plains. preference for C4 grasses although seven enamel samples indicate that Morgan and Lucas (2011) and Lucas et al. (2011) reviewed the nominal a significant proportion (up to ~ 50 %) of C3 browse was probably species of Stegomastodon including some no longer considered valid. included in the diet of some of the individuals sampled (Feranec and They regarded S. primitivus Osborn, based on a specimen from the late MacFadden, 2000, p. 162). early Blancan Sand Draw Lf of Nebraska, as the most primitive species of Stegomastodon characterized by cheek teeth with relatively simple Equus sp. trefoils, second molars with three lophs/lophids, and third molars with Figures 34A-G 5-6 lophs/lophids despite the fact, as Savage (1955, p. 66) noted, that Referred specimens. Pit C: 4269, right dentary with symphysis the morphology of the S. primitivus sample described by Osborn (1936) (missing incisors) and p2-m3; 4270, left dentary with p3-m3 (probably overlaps that of the late Blancan Cita Canyon and Blanco Formation same individual as 4269); 4271, right dentary with p2-m3; 4295, samples assigned to S. mirificus thus leading Savage (1955) to express anterior part of both dentaries with symphysis, all incisors, right skepticism about the validity of S. primitivus. Lucas et al. (2011) also canine, broken left canine, right p2 and p3, broken left p2, p3,and p4; regarded S. rexroadensis Woodburne (1961) from the early Blancan 4296, dentary fragment with two worn teeth; 4292, isolated incisors Rexroad LF of Kansas, as a junior synonym of S. primitivus. S. mirificus, and canines; 4293, isolated lower molars and premolars; 4294, isolated 51

FIGURE 34. Equus sp. : A, right lower dentition, 4269, Pit C; B, left lower premolar,4181, Pit D; C, left metacarpal, 4282, Pit C; D, first phalanx, 4481, Pit C; E, first phalanx, 4284, Pit C; F, second phalanx, 4482, Pit C; G, second phalanx, 4483, Pit C. Nannippus peninsulatus: H, left upper molar UMMP 50254, Pit C; I, right upper molar, 4264, Pit C. 52 TABLE 18. Measurements (in mm) of upper and lower teeth of astragalus; 4514, distal end of metapodial; 4512, proximal phalanx; Nannippus peninsulatus from Red Corral sites. 4515, medial phalanx; 4518, medial phalanx; 4519, medial phalanx; 4520, right ectocuneiform; 4521, magnum. Loc. 5: 4525, associated left p2-m2 and right m1-m3; 4529, right Tooth Length Width Protocone dentary with p2-m3; 4527, associated right dp2-dp3 and left dp2; 4528, length two lower left deciduous premolars; 4526, palate with right DP2-DP4 Pit C and left DP3-DP4; 4530, left tibia; 4531, distal right tibia; 4532, right 4264 right M1? 16. 7 15. 1 6. 1 metacarpal; 4533-4537, four distal ends of metapodials; 4538, 4539, 4265a left M1 brkn. 17. 1 6. 3 4541, 4543, four proximal phalanges; 4542, medial phalanx; 4540, 4265b left M2 18. 2 17. 5 8. 5 associated proximal and medial phalanges; 4544, right navicular; 4545, splint bones. 4265c left M3 19. 2 15. 7 9. 5 Additional unstudied horse teeth and other material are in the Pit D Frick Collection and the Panhandle-Plains Historical Museum. 4172a right M 19. 2 18 6. 9 Description. A medium-sized horse is best represented at Pit C 4172b left M 19. 9 17. 5 8. 4 by several dentaries bearing complete or nearly complete dentitions. A right dentary, 4269 (Fig. 34A), bears the edentulous symphysis and p2-m3 with an occlusal length of 167. 2. A left dentary, 4270, contains Metaconid- the alveolus of p2 and p3-m3 with an occlusal length of 136. 5. The two Tooth Length Width Metastylid jaws probably represent a single individual, as the size, shape, and wear length stage of the teeth are nearly identical, and there appear to be two points Pit C of contact across the left p2 alveolus despite weathering of the broken 4268a left p2 19 12. 2 9. 9 edges. In the lower molars, the ectoflexid penetrates slightly into the 4268b left p/m 17. 2 11 12 isthmus between the pre- and post-flexids (further in m1 than in m2 or 4268c left p/m 16. 5 10. 5 10. 8 m3). The entoflexid between the metaconid and metastylid is broad and V-shaped. A right dentary, 4271, contains p2-m3 that are slightly more 4268d left m 19 12. 3 13 worn with an occlusal length of 170. 9. The ectoflexid in the molars just 4268e left m 20. 2 10. 2 11. 2 reaches but does not penetrate into the isthmus between the pre- and 4268f left m 19 11. 4 13. 5 post-flexids, and the entoflexid is also broad and V-shaped. A mandible, 4268g left m 17. 5 11. 8 11. 4 4295, contains all incisors, canines (left broken), left p2 (broken), p3, 4268h left p/m 15. 7 10. 8 10. 6 p4, and right p2-p3. Width across the incisors = 64. 0. Individual cheek tooth measurements from the above specimens as well as those of lower 4268i left m3 19. 5 8. 7 10. 1 teeth from Pit D and Loc. 5 are given in Table 19. No maxillaries or 4268j right p2 15. 8 10. 2 9. 2 associated upper dentitions were collected at Pit C. Numerous upper 4268k right p/m 16. 1 10. 9 10. 9 and lower molars, adult and deciduous premolars in different wear 4268l right p/m 16. 2 10. 2 10. 7 stages are present in the sample, however. In the upper teeth, the 4268m rightp/m 15. 5 9 11 fossettes are simple, and the protocones are not greatly elongated. Two upper teeth show the development of a small pli caballin fold. The 4268n right p/m 17. 2 10. 6 10. 7 occlusal length and width of the largest upper premolar (right) are 29. 4268o right p/m 16. 5 11. 5 11. 5 9 and 32. 5, respectively; the occlusal length and width of the smallest 4268p right p/m 18. 1 9. 9 10. 4 upper molar (left) are 24. 0 and 25. 5, respectively. The ectostyles are 4268q right m3? 19. 9 10. 6 11. 5 well-developed in the premolar. Both teeth are moderately worn. A few 4268r right m3 21. 5 8 10. 4 of the lower molars are narrower than the rest, although there is little 4268s right m3 21. 3 7. 4 10 variation in occlusal length at any given wear stage. In seven lower molars the ectostylid deeply invades the isthmus between the pre- and 4268t right m 15. 6 10. 1 11. 2 post-flexids. In the remaining molars in which the occlusal pattern is Pit D clearly discernable, the ectostylid just reaches the isthmus. 4173a right p2 17 10. 3 9. 1 At Pit D, where bone preservation is poor, Equus is best 4173b right p/m 17. 1 11. 5 11. 5 represented by an associated left and right lower dentition, 4181 (Fig. 4173c right p/m 18. 3 12 11. 7 34B), lacking both m1s. The teeth are those of a young adult and are very hypsodont. The ectoflexid penetrates just to the base of the isthmus 4173d right p/m 18 12. 7 12. 6 between the pre- and post-flexids in m2 but well into the isthmus in 4173e right p/m 16. 7 9. 9 9. 6 m3. The entoflexids are wide and V-shaped. A left dentary fragment, 4173f right p/m 17. 9 10. 2 10. 3 4178, contains p2-m3 in an advanced stage of wear. In m2 and m3, 4173g left p2 18 11 9 the ectostylid also penetrates just to the isthmus and the entoflexid is Loc. 5 broad and V-shaped. Measurements of 4181 and 4178 are given in Table 19. Several isolated lower cheek teeth include molars in which 4548a right p 18. 2 12. 1 12. 4 the ectoflexid penetrates to or into the isthmus. No maxillaries are 4548b right m 19. 3 10. 1 10. 9 present, but 4180 consists of an associated left P2-M2 and right M2- upper molars and premolars; 4298, lower right molar; 4481, lower right M3 of a very young adult. The teeth are very hypsodont and lingually molar; 4272, lumbar vertebra; 4273, lumbar vertebra; 4274, lumbar curved. P4 and M3 are unerupted, and an extremely worn left DP4 was vertebra; 4299, distal right tibia; 4482, distal right tibia; 4275, left associated with the unworn P4. The protocones in the newly erupted calcaneum; 4297, right calcaneum; 4276, right astragalus; 4277, right teeth are somewhat elongated, pointed at their extremities, and possess astragalus; 4278, left astragalus; 4279, right astragalus; 4280, patella; a slight lingual indentation. However, the fossettes are simple, and the 4281, proximal right metacarpal; 4282, left metacarpal; 4283, 4284, styles are not strongly developed. Several isolated upper molars show 4481, three proximal phalanges; 4285, 4286, 4482-4485, six medial shorter protocones as well as simple fossettes. In all upper teeth present, phalanges; 4287, distal phalanx; 4288, distal phalanx; 4289, two left the connection of the protocone to the protoselene is about 1/3rd of the naviculars and two sesamoids; 4290, splint bones; 4291, petrosal bones. distance from the anterior end of the protocone. Measurements of 4180 Pit D: 4181, associated lower left and right dentitions with p2-p4 and several other upper teeth are given in Table 20. and m2-m3; 4178, left dentary with p2-m3; 4182, isolated lower molars At Locality 5, in a small draw west of Pit D, several specimens and premolars; 4183, lower deciduous premolars; 4180, associated left were collected, including 4529, a right dentary with p2-m3. The teeth P2-M2 and right M2-M3; 4184, upper molars and premolars; 4179, are broken and unmeasurable, although the molars show a slight incisors; 4186, incisor; 4185, left astragalus; 4201, left astragalus; 4202, invasion of the ectoflexid. No. 4525 consists of associated lower left proximal phalanx; 4203, periotic; 4204, left cuboid; 4205, splint bones. p2-m2 and right m1-m3 of a young adult. The ectoflexids in the molars Pit A: 4522, left tibia; 4523, proximal end of right metacarpal; extend to but not into the isthmus, and the entoflexids are broad and 4524, carpal. V-shaped. Measurements of 4525 are given in Table 19. Pit B: 4513, right astragalus; 4516, right astragalus; 4517, left Postcranial elements were collected at all five localities and 53 TABLE 19. Measurements (in mm) of lower teeth of Equus sp. from Red Corral sites. L = length; W = width. Dentition p2 p3 p4 m1 m2 m3 L W L W L W L W L W L W Pit C 4269 right 31. 8 18 28. 2 19. 8 28. 1 19. 4 25. 5 17. 6 24. 5 16. 9 27. 7 15. 4 4270 left NA NA 28 19. 4 27. 8 19. 4 24. 8 17. 5 24. 5 16. 6 27. 3 15. 2 4271 right 32. 5 17. 2 29. 3 20. 5 28. 2 19. 5 25 17. 1 26. 2 15 29 14. 6 4295 28. 4 18. 9 26. 8 18. 9 26. 5 19 NA NA NA NA NA NA Pit D 4181 left 35. 3 17. 8 29. 9 16. 2 32. 8 20. 5 NA NA 27. 8 17. 5 24. 8 14 4181 right 35. 6 17. 8 29. 7 16. 2 32. 6 20. 4 NA NA 27. 5 17. 3 24. 7 14 4178 left 33 17. 2 28. 3 19. 1 26. 4 19. 4 23 17. 4 25. 7 18. 9 34. 6 15. 6 Loc. 5 4525 left 30 16. 8 28. 6 20 28. 8 brk 27. 5 17. 8 31. 4 16 NA NA 4525 right NA NA NA NA NA NA 27. 5 17. 7 31. 6 15. 9 unworn

TABLE 20. Measurements (in mm) of upper teeth of Equus sp. from incisor are in the Frick Collection of the American Museum of Natural Red Corral Pit D. History but were not examined. Tooth Length Width Protocone Description. The upper canine (Fig. 35A) shows a prominent anterior wear facet and is broken across the tip. The greatest length Pit D anteroposterior dimension is 21. 9, and the greatest width is 12. 9. Remarks. The Red Corral fossils are too fragmentary for 4180 left P2 39. 6 26. 6 9. 5 species identification, although they very likely belong to Platygonus 4180 left P3 31. 5 26. 7 14. 5 bicalcaratus, the most common Blancan species of peccary. Family Camelidae 4180 left P4 31. 2 27. 1 16. 2 Camelops sp. 4180 left M1 29. 9 27. 6 13. 9 Figure 35D 4180 left M2 30. 3 24. 2 15. 1 Referred specimens. Pit C: 4251, left dentary with dp3-dp4 and m1-m2. WT Loc. 5, draw west of Pit D: 4549, left radius-ulna; 4546, proximal end of a proximal phalanx. 4184a left P3 32. 4 30. 7 16 Description. Remains of this camel are rare in the fauna. The dentary, 4251, is that of a young individual (Fig. 35D). It is broken 4184b left M1 or M2 28 28 11. 8 anterior to the dp3 and behind m2. A detached portion of the ascending ramus and coronoid process was also found. The rooted dp3 and 4184c left M3 28. 5 25. 1 15. 4 3-cusped dp4 are much worn and were about to be shed. The m1 is 4184d left M3 28. 7 23. 5 16. 3 fully erupted; the m2 is erupted, but there is little or no wear on the posterior lobe. Occlusal tooth measurements are: dp3 = 15. 5 x 12. 4; dp4 = 49. 7 x 20. 6 (across 3rd lobe); m1 = 42. 7 x 17. 8; m2 = 48. 9 x presumably belong to the same species as the dentitions. These include 20. 5. Medial jaw depth below dp4 is 50. 7 and below the posterior lobe two tibiae; two calcanea; 7 astragali; a left metacarpal, 4282 (Fig. 34C); of m2 is 82. 5. and several phalanges (Figs. 34D-G). Measurements of these elements The left radius-ulna, 4549, is missing the ulnar process. The are given in Table 21. length of the complete radial portion is 470. The greatest width of the Remarks. At least some of the Red Corral dentitions and isolated proximal end across the lateral tuberosity is 81. 5. The width of the teeth are probably referable to Equus (Dolichohippus) simplicidens, proximal articular surface is 75. 0, and the width of the distal articular a common Blancan horse, based on the simple fossettes and short surface is 79. 0. The greatest width across the distal end is 88. 4. The simple protocones in the upper teeth and the fact that in some of the distal interosseous foramen is small. The proximal phalanx, 4546, is lower molars, the ectoflexid penetrates into the isthmus between the broken. Width and depth across the proximal end are 35. 2 and 33. 5, pre- and post-flexids, and the valleys between the metaconid and respectively. metastylid are V-shaped. E. scotti, another large horse found in Blancan Remarks. Of the three best known genera of Blancan camels, and Irvingtonian faunas, is larger and has more complex fossettes and the dentary and radius most closely match the genus Camelops in size. longer protocones on the upper molars and lacks the deep ectoflexids They are too large to be those of Hemiauchenia and too small to be on the lower molars. Equus cumminsi is a much smaller horse and quite those of Gigantocamelus. Although remains of large camels are fairly rare in Blancan faunas and is still poorly known. common in many Blancan faunas, identification ofCamelops species is The calcanea and astragali seem smaller and the metacarpals and difficult when based on lower jaws alone. the proximal phalanges more slender compared with measurements of similar bones assigned to Equus (D. ) simplicidens from other Blancan Hemiauchenia cf. blancoensis (Meade, 1945) faunas. The left metacarpal, 4282 (Fig. 34C), has a length to width ratio Figure 35B of 5. 65 which is close to the minimum ratio given by Winans (1989) Referred specimens. Pit B (WT Loc. 3): 4511, first phalanx. Pit for her E. francisci group and suggests the possible existence of a stilt- C: 4252, partial left dentary with m1-m3; 4253, isolated lower teeth; legged horse in the fauna such as E. calobatus, which is based on a 4254, upper premolar; 4255, four incisors; 4256, complete proximal long and slender metacarpal but lacks an associated skull or dentition. phalanx; 4257 and 4258, distal ends of two metapodials; 4259, distal It seems likely that there is only one large horse in the Red Corral LF, end of proximal phalanx; 4260, fibula; 4501, distal right tibia epiphysis; however, and that the postcranial elements belong to the same species Tentatively referred: 4261, left calcaneum; 4480, right calcaneum; as the dentitions. Morgan et al. (2008) recognize several large to 4262, left astragalus; 4263, right astragalus; 4497, left cuneiform; 4498, medium-sized horses from the Blancan age Pearson Mesa LF in the left cuneiform; 4499, right unciform; 4500, scaphoid. Pit D: 4206, six Duncan Basin in southwestern New Mexico – some of which are only incisors. Loc. 5: 4546, proximal end of proximal phalanx. Additional assigned to generic level. material from Pits A, B, C, and D is in the Frick Collection of the Order Artiodactyla American Museum of Natural History but was not examined. Family Tayassuidae Description. A small llama is represented at Pits B, C, and D Platygonus sp. by fragmentary material. A partial left dentary fragment, 4252 (Fig. Figure 35A 35B), from Pit C is that of an old individual. The teeth are sufficiently worn so that no trace of the anterior external buttress exists on m2, Referred specimens. Pit C: 4250, upper canine. Pit D: 4121, tooth although one is present on m3. The posterior lobe of m1 and complete fragments. A dentary fragment with two teeth and an isolated molar and m2-m3 are present. Measurements are: m2 = 27. 8 x 16. 4; m3 = 38. 54 TABLE 21. Measurements (in mm) of postcranial elements of Equus sp. from Red Corral sites. Abbreviations: L = length; W = width; D = depth; Prox. = proximal; Dist. = distal. Bone element L Prox. W Prox. D Shaft W Dist. W Dist. D Metacarpal 3 4282 left Pit C 243 42. 9 28. 6 29. 8 40. 1 29. 1 4281 right Pit C >38. 9 29. 9 4532 right Loc. 5 44. 2 32. 2 28 4523 right Pit A 46. 4 33. 2

Dist. Metapodial 3 4514 Pit B 46. 2 31. 3 4533 Loc. 5 30. 1 42. 2 32. 4 4534 Loc. 5 47. 4 36. 6 4535 Loc. 5 40. 2 31. 7 4536 Loc. 5 37. 3 30 4537 Loc. 5 40 29

Prox. Phalanx 4512 Pit B >73 49 >33. 4 30 34 20. 1 4283 Pit C 76. 6 39. 5 27. 9 brk. brk. 18. 9 4284 Pit C 72. 5 41 28. 8 25. 1 33. 2 19. 9 4481 Pit C 74. 8 46. 8 31. 9 26 35. 3 21. 8 4202 Pit D >78. 2 brk. brk. 33. 1 brk. brk. 4538 Loc. 5 79. 2 43. 8 29. 5 25 34. 6 20. 1 4539 Loc. 5 82 brk. 28. 1 29. 4 40. 7 21. 5 4540a Loc. 5 78. 9 brk. 34. 7 30. 7 39. 5 23. 5 4541 Loc. 5 71. 9 48 33. 8 29. 6 33 19. 2

Medial Phalanx 4515 Pit B 47. 5 51. 1 34. 6 47. 4 28. 9 4518 Pit B 39. 7 38. 6 28. 3 37. 2 22. 5 4519 Pit B 40. 7 brk. 29 36. 5 >22. 5 4285 Pit C brk. brk. 26. 8 41. 6 23. 4 4286 Pit C 38. 3 38. 7 27. 1 32. 6 21. 2 4482 Pit C 43 43. 7 29. 3 38. 7 25 4483 Pit C 41. 2 39 25. 9 33. 8 19. 6 4484 Pit C 40. 1 40 26. 6 36. 9 23. 5 4485 Pit C 38. 5 41. 3 26. 5 37. 8 20. 5 4540b Loc. 5 47. 2 46. 6 30. 2 42. 2 25. 4 4542 Loc. 5 44 44. 6 30. 5 36. 6 24. 2

Distal Phalanx 4287 Pit C 52. 4 40. 1 facet 4288 Pit C 44. 3 34. 3 facet

Tibia 4522 left Pit A 69. 2 47 4530 left Loc. 5 47. 5 74 50. 7

Calcaneum 4275 left Pit C 103. 8 46 48. 2 31 40. 1 4297 right Pit C 104. 8 46. 5 46. 3 31. 6 c. 47. 8

Astragalus 4513 right Pit B 55. 3 42 facet 4516 right Pit B 59. 4 c. 49 (brk) 4517 left Pit B 54 44. 1 facet 4276 right Pit C 61. 2 49. 6 facet 4277 right Pit C 53. 3 37. 2 facet 4278 left Pit C 56. 7 44. 6 facet 4279 right Pit C 59. 5 48. 8 facet 55

FIGURE 35. Platygonus sp. : A, upper right canine, 4250, Pit C. Hemiauchenia cf. blancoensis: B, left dentary, m1-m3, 4252, Pit C. Capromeryx sp. : C, left m3, UCMP 43393, Pit C. Camelops sp. : D, left dentary, dp3-dp4, m1-m2, 4251, Pit C.

1 x 15. 5. Other isolated lower teeth and tooth fragments, 4253, and of Tanupolama (= Hemiauchenia) from Broadwater A, Lisco B, and an upper premolar, 4254, are of comparable size. The lower teeth Gordon-Hay Springs-Rushville, Nebraska. Measurements of the Red are in various wear stages, and several possess the llama buttresses. Corral calcanea are: 4261 (left):L = 130. 0, W across astragalar facet Four small incisors, 4255, are referred. Measurements of a complete = 48. 5, greatest anterior height across parasustentacular facet = 55. proximal phalanx, 4256, are: L = 91. 3; proximal W and depth = 26. 2, posterior W and height = 32. 7 and 38. 0 respectively; 4480 (right 2 and 26. 7; distal W and depth = 22. 0 and 19. 9. Two calcanea and juvenile lacking posterior epiphysis): W across astragalar facet = two astragali are tentatively referred. They appear to be too small to be 40. 5, greatest anterior height across parasustentacular facet = 45. 9. those of Camelops judging by measurements given by Webb (1965) Measurements of the Red Corral astragali are: 4262 ( left): Length for Camelops hesternus. According to measurements given by Breyer (lateral = 81. 2, medial = 71. 8, minimum = 60. 7) and distal width = 53. (1974), the calcanea appear to be about the size of those of Tanupolama 8; 4263 (right): Length (lateral = 79. 0, medial = 72. 2, minimum = 59. (now Hemiauchenia) from Gordon-Hay Springs-Rushville, Nebraska. 5) and distal width = 52. 5. However, the astragali appear to more closely resemble in size those Remarks. The Red Corral dentary and teeth compare favorably of Camelops from Broadwater A, Nebraska, and are larger than those with those of the type of Hemiauchenia blancoensis in size and 56 development of the anteroexternal buttresses. Hemiauchenia is the Genus and species indeterminate most frequently occurring species of llama in Blancan faunas of the A 3-inch antler fragment without tines, UCMP 43405, from Pit C United States. Stable Carbon 13 isotope values in tooth enamel studies is indistinguishable from that of Odocoileus, the white-tailed or mule of Hemiauchenia in Florida indicate a preference for a C3 browse diet deer, but is inadequate for even generic assignment. It may represent an in Blancan time but with a higher proportion of C4 grasses through extinct genus of cervid. Irvingtonian and Rancholabrean time during the Pleistocene (Feranec and MacFadden, 2000; Feranec, 2003; Kohn et al., 2005; and Yann and AGE AND CORRELATION DeSantis, 2014). Several methods of more finely subdividing the Blancan in an Family Antilocapridae attempt to achieve better temporal resolution have been proposed over Capromeryx sp. the last 40 years. As noted by Bell et al. (2004, p. 252) “most of them Figures 29D, 35C rely on the first and last appearances of certain mammalian taxa in specified stratified sequences or isolated localities. These appearances Referred specimens. Pit C: UCMP 43393, left m3; 4503, molar reflect immigration and extinction events and progressive species fragment; 4504, astragalus. Pit D: 4119, isolated teeth; 4120, broken evolution within particular lineages. Such efforts may be hampered phalanx; F:AM 117078, left dentary with p2-m3 (broken). An upper by problems of provinciality. Latitudinal, regional, elevational, and molar from Pit C and an isolated right m3 from Pit D are in the Frick ecological factors lead to faunal provincialism that, together with the Collection of the American Museum of Natural History but could not lack of radiometric and paleomagnetic control, can make correlation of be found for study. faunas difficult. Despite such difficulties, some progress has been made Description. The left m3, 43393 (Fig. 35C), from Pit C is in dividing the Blancan, although to date no single method or proposal approximately 34 high. The occlusal length is 16. 0 and the occlusal is universally adopted or considered universally applicable. ” width is 5. 0. The left dentary, 117078, from Pit D (Fig. 29D) is broken Several attempts have been made to establish arvicoline rodent across m3 and the ascending ramus is missing. The occlusal length of zones for the Blancan and Irvingtonian (L. D. Martin, 1979; Repenning, p2-m2 is 37. 5. The length and width of the individual lower molars 1987; R. A. Martin, 2003). In recent years, increasing interest has in the dentary are m1 = 9. 5 x 5. 5, m2 =11. 0 x 6. 3 and m3 = 15. 5 been focused on the second phase of the Great American Biotic est. x 6. 3 (posterior loop is missing). Estimated length of p2-m3 is Interchange (GABI) between North and South America. Some workers 53. 5. Lingual jaw depth below m1 = 19. 5 and below anterior of m3 (e. g. Morgan, 2008) define the late Blancan in temperate North = 27. 2. Maximum jaw width at m2 = 9. 3 and at m3 = 10. 9. Tooth America as beginning with the appearance of certain South American measurements are given in Table 22. immigrants such as the xenarthrans Eremotherium, Paramylodon, and Remarks. Antilocaprid remains are usually uncommon but widely Glyptotherium and the rodents Neochoerus and Erethizon in faunas in distributed in Blancan faunas of the western United States. Fossils the southeastern and/or southwestern United States at about 3. 0 Ma usually consist of isolated teeth, jaw fragments, and post-crania and (first appearance of interchange mammals in the southwestern United are listed as antilocaprid indeterminate, or sometimes as Capromeryx States). Early Blancan faunas would date between about 4. 9 and 3. 0 sp. Horn cores, necessary for species identification, are rarely found. Ma, whereas late Blancan faunas might date as late as 1. 8 Ma at the Two species based on horn cores are known from Blancan faunas in end of the Olduvai subchron. In terms of the paleomagnetic time scale, the United States. C. tauntonensis, a larger species, based on a cranium Blancan faunas would span the later part of the Gilbert reversed chron, with the lower portion of the horn cores and associated teeth from the all of the Gauss normal chron (3. 58-2. 58 Ma) and the early part of late early Blancan Taunton LF of Washington was described by Morgan the Matuyama reversed chron. Another perspective suggests that the and Morgan (1995). C. arizonensis, a smaller species, is based on a left Blancan-Irvingtonian boundary be set at 2. 0 Ma, coincident with the horn core and cranial fragment from the late Blancan 111 Ranch LF Microtus immigration event on the Central Great Plains (Martin et al., of Arizona (Skinner, 1942). The premolars of FM 117078 are shorter 2008; Martin and Peláez-Campomanes, 2014), bounded below by the but wider than those associated with the type of C. tauntonensis, but Huckleberry Ridge ash (2. 11 Ma) and above by the Olduvai subchron the first and second molars closely match in size those of the Taunton (1. 95 Ma) in the Borchers Badlands of Meade County, Kansas. sample. The two m3s from Red Corral are shorter but comparable Assuming that sediments containing the Red Corral LF were in width to those in the Taunton sample. Jimenez-Hidalgo et al. deposited near the second phase of the GABI, the fauna probably falls (2004) referred some isolated teeth from Guanajuato, Mexico, to C. near the beginning of the late Blancan (contra early Blancan in Janis et tauntonensis, although horn cores were absent. Morgan et al. (2011) al., 1998, p. 637, SP1G; Janis et al., 2008, p. 713, SP1G). Paramylodon gave a brief description and measurements of isolated teeth from two cf. garbanii is present based on a single tooth from Pit B and a left Blancan faunas in New Mexico but assigned them only to genus. Table dentary containing the last two teeth from Pit C. However, no remains 22 gives comparative measurements of these teeth. of Glyptotherium have been found in the fauna. Both taxa are present Family Cervidae in the upper level of the Cita Canyon LF about 80 km (50 miles) to

TABLE 22. Measurements (in mm) of lower teeth of Capromeryx from Red Corral sites and other Blancan local faunas. Abbreviations: RC = Red Corral; F:AM = Frick American Museum; UC = Univ. California; WA = Washington; Mex. = Mexico; T or C = Truth or Consequences; A-P = Arroyo de la Parida; NM = New Mexico. L = length; W = width. Tooth RC Pit D RC Pit C Taunton, WA. Guanajuato, Mex. T or C, NM A-P, NM F:AM 117078 UC 43343 N OR (Mean) N OR (Mean) p2 L 4. 3 3 5. 0-5. 7 (5. 4) 2 4. 1-4. 2 (4. 15) p2 W 3 3 2. 5-2. 8 (2. 7) 2 2. 2-2. 4 (2. 3) p3 L 6. 3 3 7. 6-8. 0 (7. 8) 4 5. 6-7. 1 (6. 35) p3 W 3. 8 3 3. 2-3. 5 (3. 3) 4 3. 4-3. 6 (3. 47) p4 L 7. 5 4 8. 4-9. 2 (8. 8) 8 7. 6-9. 6 (8. 53) 9. 1 p4 W 4 4 4. 1-4. 6 (4. 3) 8 4. 0-4. 9 (4. 46) 4. 2 m1 L 9. 5 4 9. 1-10. 4 (9. 8) 5 8. 5-9. 5 (8. 9) m1 W 5. 5 4 5. 0-5. 7 (5. 3) 5 5. 2-5. 5 (5. 36) m2 L 11 6 11. 4-12. 7 (12. 0) 5 10. 3-11. 6 (10. 88) 12. 2 m2 W 6. 3 6 5. 1-6. 4 (5. 6) 5 5. 7-6. 3 (5. 9) 5. 9 m3 L c. 15. 5 16 5 17. 7-18. 9 (18. 4) 6 16. 7-17. 8 (17. 0) 17. 9 15. 7 m3 W 6. 3 5 5 5. 0-6. 2 (5. 8) 6 5. 8-6. 3 (6. 11) 6 5. 6 57 the southeast of Red Corral, but neither of these genera have been a land snail, though rare, nevertheless indicated the presence of found in Blancan faunas further north in Kansas. The Red Corral LF woodland and moist humus, but since there were so few land snails and contains several characteristic taxa that are restricted to the Blancan but most of those were so scarce, this habitat was probably not close to the range throughout most or all of that age. These include Procastoroides site of deposition. sweeti, Sigmodon minor, Borophagus diversidens, Canis lepophagus, Hibbard (1941d) described the paleoecology of the Blancan age and Nannippus peninsulatus. Present also, however, are several Rexroad LF from Meade County, Kansas, based on fossils from his taxa which first appear during middle to late Blancan time. These localities 1, 2, and 3. Later studies showed that this fauna is not a single include Miracinonyx (Savage, 1960), Sylvilagus (White, 1991), and contemporaneous unit. . As understood by Hibbard (1941d, p. 88-89) the Stegomastodon mirificus (Lucas et al., 2011). Bell et al. (2004, p. 244- Rexroad mammalian fauna at that time contained 37 identified genera 245) provide an excellent temporal range chart that includes many key and 32 identified species. The faunal list includedPliolemmus antiquus genera found in Blancan faunas. Unfortunately, radiometrically datable and Pliopotamys meadensis which Hibbard recognized might be from ash beds which could provide supporting data for age assignment are another fauna because they did not occur at Localities 2 and 3 but only lacking in the Red Corral stratigraphic section despite the fact that the at Locality 1. The fauna at Locality 1 was later shown to be younger section is fairly thick (about 60 meters). and became known as the Deer Park LF. The animals in the Rexroad Lindsay et al. (1975) reported the results of paleomagnetic faunal list were presumed to have lived together in the area during the sampling of the stratotype and related sequences of Hemphillian, Pliocene, because none of the fossils showed evidence of having been Blancan, and Irvingtonian faunas in Texas and Kansas. They found re-worked or transported any great distance before deposition. Hibbard the sediments at some sites, particularly in the Red Corral section, to grouped the fossil mammals into several communities based upon the be weakly magnetized and only partially stable to alternating fields. adaptive characters presented by them and upon the known habitats Nevertheless, the Red Corral section appears to include three normal of living species of genera represented in the fauna. He recognized an events that Lindsay et al. (1975) correlated with the Gauss chron, upland grass community (5), a semiaquatic community (2), a meadow and based on the mammalian fauna, in particular the rodents, this (3) and marsh (2) community, a forest community, and a valley slope assessment is consistent with the replacement chronology of Blancan community (4). mammalian assemblages from the Meade Basin of Kansas (Martin and Hibbard’s community model was refined by Skinner et al. (1972) Peláez-Campomanes, 2014). when they established a set of habitat communities for the Sand Draw The Red Corral section is relatively thick at about 60 meters (200 LF in north-central Nebraska. They postulated the existence of (1) ft). Paleomagnetic sampling of sediment from the fossil-bearing level at stream-bank and lake-bank communities, (2) marsh and semiaquatic Pit C yielded a normal polarity result. A questionable reversed polarity communities, (3) savanna valley communities, (4) valley slope result was obtained on sediment 5 meters (16 ft) below the fossil level communities, and (5) upland communities. These communities were and a normal polarity result was obtained about 25 meters (80 ft) below again modified and utilized by Eshelman (1975) in his analysis of the Pit C at the bottom of the hill. At Pit D, a sample taken from the fossil- White Rock LF in north-central Kansas. He recognized a permanent bearing, papery maroon shales gave a very weak but possibly normal water habitat, a stream-river habitat, a lowland meadow-savanna polarity reading, and a sample from just above in the unfossiliferous habitat, a valley slope habitat, and an upland prairie habitat. brown clay gave a reversed polarity result. About 25 meters (80 ft) More recent studies suggest that these community models are higher in the section near the upland surface, two samples yielded a too simplistic, inaccurate, or inadequate for several reasons. First, a normal polarity result. Lindsay et al. (1975) tentatively placed the Red good pollen record is needed to establish vegetation patterns and such Corral LF within the middle normal unit of the Gauss (3. 22-3. 11 Ma) evidence is usually lacking. Second, good geologic data is needed to between the Mammoth and the Kaena subchrons – earlier than the Cita establish whether a depositional site is fluvial, lacustrine, or paludal. Canyon LF of Texas and the Sanders LF of Kansas but later than the Third, as noted by R. A. Martin (written communication, 2015), the Benson LF of Arizona and the Rexroad Locality 3 LF of Kansas. It combination of heteromyids, ground squirrels, grasshopper mice, should be emphasized that this placement was tentative, and that more harvest mice, and badger shows that the predominant habitat was a magnetic samples and/or more fossils are needed to determine the prairie mosaic of some kind, at least slightly upland from the more magnetic polarity limits of the Red Corral quarries. mesic communities but this could have been as little as 2-3 m up from a Taylor (1960) noted that the molluscan fauna from Pit D was stream or lake bank. Such terrains can be seen in the High Plains today. similar to that at Rexroad Locality 3 in Meade County, Kansas, 235 Fourth, large mammals have large home ranges and freely traverse all km (146 miles) to the northeast. The fauna also shares several fossil habitats and will use streams or ponds in lowland habitats as waterholes. mammals with Rexroad Loc. 3 including Sorex taylori and Scalopus Furthermore, as pointed out by R. A. Martin (written communication, (Hesperoscalops) rexroadi. Other mammal species are like those found 2015), “large mammals are also opportunistic and will take whatever in the younger Blancan Sanders and Deer Park local faunas in Meade energy is available anywhere they can get it. The same is true for the County. In particular, the recognition of Sigmodon minor /medius at small mammals, but as they are more stenotopic they do provide more Red Corral rather than the smaller S. m /minor is important as S. minor information. ” experienced a dwarfing episode just prior to its extinction in the Meade The habitat at Pits A, B, and C appears to have been a low energy Basin of Kansas (Peláez-Campomanes and Martin, 2005). On the other stream bounded by a prairie mosaic. The sediments from which the hand, the Neotoma and Onychomys specimens are more similar to those fossils were collected were gray to buff fine silty sands and clays. from Arizona faunas. Unfortunately, arvicolids (microtines), which are Many of the fossils excavated here were isolated remains of large so useful for biostratigraphic zonation in the Great Plains, do not occur or medium-sized animals such as horse, camel, stegomastodont, and in the Red Corral LF. They are found, however, in the upper level of coyote, plus some dental and postcranial remains of the large cat, the Cita Canyon LF along with Glyptotherium and Paramylodon 80 km Miracinonyx studeri, which must have died near the site of deposition (50 miles) to the southeast. It would seem that such differences between at Pit C. The absence of water birds, frog, pond turtles, water snake, these two faunas are more likely due to differences in geologic age beaver, and aquatic snails and the near absence of shrews indicate the rather than climate/environment, given the short geographic distance absence of pond, lake, or marsh conditions at these sites. The nearby and latitude separating them. The upper Cita Canyon LF occurs in the prairie mosaic habitats are represented at Pit C by an abundance of upper normal polarity part of the Gauss magnetic chron just below jaws, teeth, and a few postcranial bones of small rodents such as the Gauss-Matuyama boundary at 2. 58 Ma. Thus, the Red Corral LF Geomys, Prodipodomys, Perognathus, ground squirrels, Bensonomys, probably dates between the first arrival ofParamylodon at about 3. 0-3. Peromyscus, Reithrodontomys, Onychomys, and Neotoma, and the 2 Ma and the Gauss-Matuyama boundary at 2. 58 Ma. [See discussion leporid Hypolagus concentrated in a small layer at the top of Pit C from below about Hudspeth and Red Light LFs] which 12 tons of matrix were screen washed. Predation by owls may PALEOECOLOGY AND CLIMATE have been responsible for their abundance at the site although no actual fossil owl pellets were found. The cotton rat, Sigmodon minor /medius, Taylor (1960) suggested, based on the abundance of the mollusks was the most abundant species collected at Pit C (at least 40 individuals). Physa anatina Lea, Gyraulus parvus (Say), Promenetus umbilicatellus Its presence indicates that some kind of mesic or semi-mesic lowland (Cockerell), and Stagnicola bulimoides techella Haldeman, that the environment was present. Sigmodon is considered a grazer and today local habitat at Pit D was a shallow pond fluctuating annually and with can be found in all kinds of grassy habitats along streams, not 2 m from thick submerged vegetation. He noted that Ferrissia rivularis was rare, slightly upland, drier prairie habitats. The modern species, Sigmodon but that it requires permanent water. He postulated that probably the hispidus, ranges today throughout much of the southern United States pond was a lagoon or oxbow lake near a permanent stream. Strobilops, and into northeastern most Mexico occurring as far north as northern 58 Kansas and Missouri. It is found today in southwestern Kansas and the McKenna of the American Museum of Natural History Division of central and eastern Texas Panhandle. Vertebrate Paleontology provided a faunal list and the privilege of The habitat at Pit D appears to have consisted of a pond, examining some of the fossil specimens in the Frick Collection early in small lake, or stream surrounded by marsh grasses. Fossils, mostly the study, and the author wishes to thank the museum for the recent loan microvertebrates, were recovered by screen washing 28 tons of matrix of selected specimens from the Proctor Ranch sites and for permission from a papery maroon shale unit. An aquatic environment is indicated to include descriptions of them in this publication. The author is also by the presence of ictalurids, frog, pond turtles, water snake, coots, indebted to the following institutions for the loan of specimens in their rails, duck, and heron as well as many of the mollusks. Moreover, the care used for comparison purposes: the University of Kansas for the water was sufficiently deep to accommodate the beaver,Procastoroides loan of rodent fossils from southwest Kansas; Texas Tech University sweeti. The most abundant mammal recovered at the site is the cotton for the loan of fossil Sigmodon and Hesperoscalops specimens from the rat, Sigmodon minor /medius, (represented by at least 139 individuals) Blanco LF; Midwestern State University for the loan of Hesperoscalops which would have lived in the nearby bordering grassy habitat. specimens from the Beck Ranch LF; the University of Nebraska for the According to Hibbard (1941d), Sigmodon was the third most abundant loan of the type specimen of Hesperoscalops mcgrewi; the University species collected from the Rexroad LF (localities 2 and 3). of Texas at Austin for the loan of the skull and skeleton of the modern The second-most abundant species collected at Pit D is the lion for comparison with specimens of Miracinonyx studeri; and the shrew, Sorex taylori, which is represented by 50 dentaries (at least 27 Panhandle-Plains Historical Museum for in house access to specimens individuals) whereas only one toothless dentary was collected at Pit from the Cita Canyon LF. C. According to Hibbard (1941d, 1953a), Sorex taylori was the most Appreciation is expressed to the following individuals for their abundant species collected from the Rexroad LF (localities 2 and 3) aid in identification of fossil material and comments on the text. Robert and was a moist, lowland dweller. Today, the majority of Sorex species Weigel of Illinois State University examined the fossil bird specimens live along streams and marshes. The genus reaches northern Kansas and provided preliminary identifications. The late J. Alan Holman of but does not extend to the Texas Panhandle today. The closest points Michigan State University provided preliminary identifications of the of known occurrence are northeastern Kansas, the edge of the Rocky fossil amphibians and reptiles in the fauna, and Gerald Smith of the Mountains in eastern Colorado (Frey and Moore, 1990), and central Museum of Paleontology at the University of Michigan identified the New Mexico (Wilson and Reeder, 2005). Sorex taylori also appears to fish as belonging to the ictalurid group. Nicholas J. Czaplewski and have lived along streams and marshes. If so, it would seem to indicate Jon Baskin offered comments on the identification of the bat jaw and that the region of southwestern Kansas and the Texas Panhandle enjoyed the Bassariscus molar, respectively. The late John A. White studied lower summer temperatures and slightly more humid conditions in the and identified the rabbit fossils and provided the author with camera Pliocene compared to conditions in the region today. lucida drawings of the diagnostic teeth. Colleagues Robert A. Martin, As noted above, it is significant that no remains of arvicolid rodents Nicholas J. Czaplewski, and Xioaming Wang critically reviewed all or such as voles, lemmings, and muskrats were recovered at any of the Red parts of the manuscript and offered many helpful comments. Above Corral sites. Such animals today are primarily northern or boreal forms. all, the author is indebted to and greatly appreciative of the late Claude The Red Corral LF at that time may have been too far south and climate W. Hibbard, who provided much encouragement and helpful comments conditions not sufficiently cool and moist for such species, although it early in the study. should also be noted that remains of muskrat, vole, and lemming were recovered from the slightly younger Cita Canyon LF about 80 km (50 REFERENCES miles) to the southeast (Schultz, in prep. ). Dalquest (1978) reported Akersten, W. A., 1972, Red Light local fauna (Blancan) of the Love Formation, the vole, Ogmodontomys, from the early Blancan Beck Ranch LF near southeastern Hudspeth County, Texas: Texas Memorial Museum Bulletin Snyder, Scurry County, Texas, about 354 km (220 miles) southeast of 20, 53 p. the Red Corral localities. Ogmodontomys was also the second most Albright, L. B., III, 1999, Biostratigraphy and vertebrate paleontology of the abundant mammal species at the Rexroad Locality 3 site. Arvicolids San Timoteo Badlands, southern California: University of California were also in Arizona during the Blancan and, in the early Blancan, they Publications in Geological Sciences, n. 144, p. 1-121. were at Yepomera in Mexico. Consequently, Red Corral time represents Anderson, E., 1984, Review of the small carnivores of North America during a different sampling interval from Beck Ranch and Cita Canyon. the last 3. 5 million years; in Genoways, H. H. and Dawson, M. R., Arvicolids are also absent from the Blanco (Meade, 1945; Dalquest, eds., Contributions in Quaternary vertebrate paleontology: A volume 1975), Hudspeth (Strain, 1966), and Red Light (Akersten, 1970) late in memorial to John E. Guilday: Carnegie Museum of Natural History Blancan local faunas. 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