sign in sign up
<<
Home , Camelops, Columbian Mammoth, Smilodon

The sabertooth fatalis (Mammalia: ) from a () site in the Pecos River valley of southeastern New Mexico/ southwestern Gary S. Morgan and Spencer G. Lucas, New Mexico Museum of Natural History, 1801 Mountain Road NW, Albuquerque, NM 87104 Abstract We describe a nearly complete dentary of the sabertooth cat Smilodon fatalis from the 25 Mile Stream site, a Pleistocene (Rancho- labrean) fluvial/alluvial deposit of the ancestral Pecos River system near Carlsbad in southeastern New Mexico. The original field data for this site are somewhat conflict- ing, so it is not certain whether the locality is in Eddy County in southeastern New Mexico or in Culberson or Reeves Counties in the Trans-Pecos region of southwestern Texas. This sabertooth dentary is very simi- lar in size and morphological characters to dentaries of S. fatalis from the Rancho in south- ern . Because of its larger size, reduced mandibular flange, and absence of p3, it differs from the late (late ) and (Irving- tonian) sabertooth S. gracilis. This mandible represents the first record of S. fatalis from southeastern New Mexico/ FIGURE 1—Map of part of southeastern New Mexico and southwestern Texas. The southwestern Texas. The only other of 25 Mile Stream site (DMNH locality 263) is located south of Carlsbad and east of S. fatalis in New Mexico is from the late the Guadalupe Mountains in one of the drainages flowing eastward into the Pecos Rancholabrean Blackwater Draw site in the River in southeastern Eddy County, New Mexico, northeastern Culberson County, east-central part of the state. The horse Texas, or northwestern Reeves County, Texas. laurentius and are also present in the 25 Mile Stream site. The presence of Bison is southeastern New Mexico/southwestern the Pecos River on 25 Mile Stream below indicative of the Rancholabrean, but a more precise age assignment is not possible with Texas, a complete left lower jaw of an adult the southern high point of the Guadalupe the limited fauna currently known from this sabertooth from a site in the Pecos River Mountains, 50 miles south of Carlsbad on site. valley south of Carlsbad. We also briefly the Carlsbad–Pecos highway, then 8–10 describe of horse and bison found in miles west.” We cannot find “25 Mile Introduction association with the sabertooth mandible. Stream” on any map of New Mexico or The specimens reported here are from Texas, including maps dating to the time The sabertooth cat Smilodon fatalis has a the vertebrate paleontology collection of period when the fossils were collected. widespread distribution in North the Denver Museum of Nature and Science Indeed, it is possible that this locality is American late Pleistocene (Rancholabrean) (formerly the Denver Museum of Natural actually in Culberson County or Reeves faunas, but it is more common in the History [DMNH]), Denver, . County in Texas, based on the fact that 1) southern part of its range, particularly Dental terminology includes: (I/i), the collectors stated the site was “50 miles California, Texas, and Florida (Kurtén and canines (C/c), (P/p), and south of Carlsbad” (it is 32 mi from Carls- Anderson, 1980). A review of New Mexico molars (M/m). Upper teeth are indicated bad to the Texas border on US–285—the Pleistocene faunas (Harris, 1993) listed by upper-case letters (e.g., P4, M2), and Carlsbad–Pecos highway; Fig. 1) and that only one published record of S. fatalis from lower teeth are indicated by lower-case let- 2) it was “below the southern high point of New Mexico, a juvenile dentary from the ters (e.g., p3, m1). All measurements of fos- the Guadalupe Mountains” (the Guada- late Rancholabrean Gray Sand local fauna, sils are in mm. lupe Mountains extend from New Mexico Blackwater Draw locality number 1, south into Texas, but the “southern high Roosevelt County, in the east-central part Locality point,” perhaps Guadalupe Peak, is in of the state (Lundelius, 1972). There are no Texas; Fig. 1). Despite these discrepancies, published records of S. fatalis from south- Harold J. Cook and J. D. Figgins collected the original collectors placed this locality western Texas (Harris, 1985; Graham, the sabertooth cat jaw and other fossils in Eddy County in New Mexico. The state 1987). The smaller late Pliocene (late described here in November 1927, from the and county boundaries in New Mexico Blancan) and early Pleistocene (early western drainage slope of the Pecos River, and Texas were well established by the ) species S. gracilis is repre- supposedly in Eddy County, southeastern 1920s, and thus we are inclined to follow sented by a mandible from the Camp Rice New Mexico (DMNH locality 263; Fig. 1). the original collectors who placed this site Formation in the Mesilla Basin, Doña Ana We have not been able to relocate this site, in New Mexico, not Texas. However, County in southernmost New Mexico and thus have reproduced the exact locali- because of the conflicting site information, (Vanderhill, 1986). Here, we report and ty description from the collectors’ field we feel it is most prudent to consider both describe the first specimen of S. fatalis from notes: “On the western drainage slope of possibilities. This site, hereafter referred to

130 NEW MEXICO GEOLOGY November 2001 as DMNH site 263 or the 25 Mile Stream of the horse Equus in the 25 Mile Stream attempted to place a species name on this site, is located south of Carlsbad and east fauna: left P3 or P4 (DMNH 1230), left M2 bison jaw. The only other bovid of similar of the Guadalupe Mountains in one of the (DMNH 1231; Figs. 2D, 2E), distal metapo- size known from Rancholabrean sites in drainages flowing eastward into the Pecos dial (DMNH 1232; Fig. 2F), and a proximal New Mexico, the musk ox Bootherium, has River in southeastern Eddy County, New phalanx (DMNH 1232; Fig. 2G). Both of the a much simpler enamel pattern on the Mexico, northeastern Culberson County, upper are comparatively large lower molars than do the m1 and m2 in Texas, or northwestern Reeves County, and have a fairly complicated enamel pat- DMNH 1234. The presence of Bison in the Texas. tern. The partial metapodial and proximal 25 Mile Stream site is significant because it There is no geologic information record- phalanx also represent large horses. establishes a Rancholabrean age. ed for DMNH site 263. However, one of Measurements of the upper cheek teeth of the fossil specimens had a small amount of the 25 Mile Stream Equus are (DMNH 1230, Discussion sediment adhering to it, which consists of a 1231, respectively): anteroposterior length very coarse to conglomeratic sand with (= ectoloph length), 30.5, 27.7; width per- The 25 Mile Stream site is not particularly and quartzite pebbles. This suggests pendicular to ectoloph, 28.2, 26.9; meso- rich or diverse, consisting of six specimens that the site was in fluvial or alluvial sedi- style crown height, 72.5, 86.5. Harris and representing three taxa. Certainly, the pres- ments that were part of the Pleistocene Porter (1980) provided a comprehensive ence of Smilodon fatalis is the most signifi- Pecos River system. series of measurements for the extensive cant feature of this site. The only other late Pleistocene sample of five species of record of S. fatalis from New Mexico is Vertebrate fauna Equus from Dry Cave, also located near from the latest Pleistocene (late Carlsbad in Eddy County, New Mexico. Rancholabrean) Gray Sand local fauna in The 25 Mile Stream Equus teeth are most Blackwater Draw (Lundelius, 1972), locat- Smilodon fatalis similar in morphology and size to teeth ed approximately 300 km (186 mi) north- The sabertooth cat Smilodon fatalis is repre- referred to E. niobrarensis from Dry Cave east of the 25 Mile Stream site. The Gray sented at the 25 Mile Stream site by a com- (Harris and Porter, 1980, table 2). Sand fossils were preserved in sediments plete left dentary with m1 and roots for the Measurements of the proximal phalanx deposited in a spring-fed pond (Lundelius, canine and p4 (DMNH 1229; Figs. 2A–C). from 25 Mile Stream (DMNH 1232: total 1972). The 25 Mile Stream site apparently This specimen possesses the morphologi- length, 89.0; proximal width, 60.7; distal represents fluvial/alluvial deposits associ- cal characters of S. fatalis, including: large width, 50.5) are also within the observed ated with the ancestral Pecos River system. size, long post-canine diastema, reduced range of proximal phalanx measurements It may be significant that the only records mandibular flange, single large mental of E. niobrarensis from Dry Cave (Harris of S. fatalis in New Mexico are in two open foramen positioned below diastema near and Porter, 1980, table 1). Although identi- sites characterized by freshwater deposits. ventral margin of ramus, greatly reduced fied as E. niobrarensis by Harris and Porter Although S. fatalis is widespread in North coronoid process, reduced lower canine, (1980), we follow Winans (1989) and Harris American late Pleistocene faunas (Kurtén p3 absent, and posterior edge of proto- (1993), who referred the large late and Anderson, 1980), it is generally rare, conid on m1 serrated. The only other spec- Rancholabrean horse from Dry Cave to the with the notable exception of Rancho La imen of S. fatalis from New Mexico, a juve- Equus laurentius group. E. laurentius occurs Brea where over a thousand individuals nile dentary with partially erupted decidu- in more than 20 Rancholabrean sites have been documented (Merriam and ous canine and dp3 from the Gray Sand throughout New Mexico (Harris, 1993). Stock, 1932; Miller, 1968; Stock and Harris, local fauna at Blackwater Draw in 1992). The sabertooth cat is absent from Roosevelt County (Lundelius, 1972, figs. Bison sp. late Rancholabrean cave faunas in New 122a,b), cannot be directly compared to the Bison is represented in the 25 Mile Stream Mexico, including the large concentration 25 Mile Stream dentary because they lack site by a partial left mandible with m1–m3 of cave deposits in the Guadalupe equivalent teeth. The single specimen of S. and roots of p3–p4 (DMNH 1234; Figs. 2H, Mountains in Eddy County, most of which gracilis known from New Mexico 2I). Measurements of the teeth of DMNH are located within 50 km (30 mi) or less of (Vanderhill, 1986), a dentary with p3 and 1234 are: m1 length, 29.0; m1 width, 20.6; the 25 Mile Stream site (Harris, 1993). With m1 from a Blancan–Irvingtonian transi- m2 length, 31.7; m2 width, 19.5, m3 (dam- the exception of Muskox Cave, large tional fauna in the Mesilla Basin, is consid- aged, not measurable). Because Bison can are represented in the Guadalupe erably smaller than DMNH 1229 (length of be identified to the species level only with Mountains caves only by the mountain m1: 22.1, 29.3, respectively), and also dif- well-preserved horn cores, we have not concolor, which still inhabits this fers in having a p3. Measurements in Table 1 clearly demonstrate that the 25 Mile TABLE 1—Measurements (in mm) of the dentary and lower teeth of Smilodon fatalis from the 25 Mile Stream Smilodon mandible falls within the Stream site and the Rancho La Brea local fauna in southern California. Measurements of the Rancho observed range for all measurements of La Brea S. fatalis are from Merriam and Stock (1932) and Berta (1985), and include the mean and the dentary and lower dentition in the observed range (in parentheses) for 25 individuals. large sample of S. fatalis from the Rancho Measurements 25 Mile Stream site, Rancho la Brea, La Brea tar pits in southern California. New Mexico/Texas California For use of the name Smilodon fatalis, we (DMNH 1229) follow Kurtén and Anderson (1980) and Total length (mandibular Kurtén and Werdelin (1990), who regarded symphysis to articular condyle) 208.7 209.5 (178.3–230.0) all North American late Pleistocene Length of post-canine Smilodon as a single species, S. fatalis. These diastema (c–p4) 70.6 61.7 (46.3–71.8) Alveolar length of authors considered S. fatalis and the con- mandibular toothrow (p4–m1) 57.6 54.1 (48.3–60.9) temporary South American species S. pop- Depth of ramus below m1 45.3 40.3 (36.0–45.6) ulator to be separate species, although Height of coronoid process 66.5 68.9 (60.3–76.3) Berta (1985) referred all late Pleistocene Length of lower canine 13.71 14.7 (13.0–16.6) Smilodon in and South Length of p4 25.91 24.6 (22.5–26.8) America to S. populator. Length of m1 29.3 28.7 (25.9–32.1) Width of m1 13.6 14.3 (12.8–16.1) Equus laurentius 1The length of the lower canine and p4 in DMNH 1229 are measurements of the alveolus, as these two teeth There are four fossils of an extinct species are missing in this specimen.

November 2001 NEW MEXICO GEOLOGY 131 132 NEW MEXICO GEOLOGY November 2001 FIGURE 2—Mammalian fossils from the Ran- 1996). The mammalian fauna from the Kurtén, B., and Anderson, E., 1980, The Pleistocene cholabrean 25 Mile Stream site (DMNH locality Roswell sites consists of a large horse of of North America: Columbia Univer- 263), southeastern New Mexico/southwestern the Equus laurentius group, , Bison, sity Press, New York, 442 pp. Kurtén, B., and Werdelin, L., 1990, Relationships Texas. A. medial view, B. lateral view, C. and the Columbian Mammuthus occlusal view, Smilodon fatalis, left dentary with between North and South American Smilodon: m1, DMNH 1229, D. occlusal view, E. medial columbi. Like the 25 Mile Stream site, the Journal of Vertebrate Paleontology, v. 10, pp. view, Equus laurentius, left M2, DMNH 1231, F. age of the Roswell fauna cannot be deter- 158–169. Equus laurentius, distal metapodial, DMNH mined more precisely than Rancholabrean. Logan, L. E., 1981, The mammalian fossils of 1232, G. Equus laurentius, proximal phalanx, Pecos River deposits in the vicinity of Fort Muskox Cave, Eddy County, New Mexico; in Beck, B. F. (ed.), Proceedings of the Eighth DMNH 1232, H. lateral view, I. occlusal view, Sumner in De Baca County have produced International Congress of Speleology, v. 1, pp. Bison sp., left dentary with m1–m3, DMNH fossils of Mammuthus, Equus, and Camelops 159–160. 1234. Scale bars are 1 cm for D, E; 2 cm for A–C, (Lucas and Effinger, 1991; Morgan et al., Lucas, S. G., and Effinger, J. A., 1991, Mammuthus F–I. 2001). Axial river deposits of the ancestral from Lincoln County and a review of the mam- Pecos River system, extending from the moths from the Pleistocene of New Mexico; in vicinity of Fort Sumner in De Baca County Barker, J. M., Kues, B. S., Austin, G. S., and Lucas, region, and the onca S. G. (eds.), Geology of the Sierra Blanca, (Harris, 1993). The cheetah-like cat south approximately 300 km (186 mi) to Sacramento, and Capitan Ranges, New Mexico: Miracinonyx trumani and the the vicinity of the Texas border, have pro- New Mexico Geological Society, Guidebook 42, Panthera atrox occur in Muskox Cave, duced a fairly typical Pleistocene large pp. 277–282. together with Puma concolor (Logan, 1981). fauna, including sabertooth cat, Lucas, S. G., and Morgan, G. S., 1996, Pleistocene The presence of Bison establishes a several species of horse, , bison, and vertebrates from the Pecos River valley near mammoth. Most of these sites are Roswell, Chaves County, New Mexico: New Rancholabrean age (probably between 300 Mexico Geology, v. 18, no. 4, pp. 93–96. and 10 ka) for the 25 Mile Stream site, but Rancholabrean in age, but more field work Lundelius, E. L., Jr., 1972, Vertebrate remains from a more precise age assignment is not possi- is necessary to further refine the ages of the Gray Sand; in Hester, J. J. (ed.), Blackwater ble with the limited fauna present. The these faunas within the Rancholabrean. Draw Locality No. 1—a stratified early-man site species of Bison in the site cannot be deter- Acknowledgments. We thank Logan in eastern New Mexico: Fort Burgwin Research mined, and the horse Equus laurentius (pre- Ivy for his help during our visit to the Center, Publication no. 8, pp. 148–163. Merriam, J. C., and Stock, C., 1932, The Felidae of viously referred to E. niobrarensis) occurs DMNH and for loaning us the mandible of Rancho La Brea: Carnegie Institution of throughout the Rancholabrean. Smilodon Smilodon fatalis from the 25 Mile Stream , Publication no. 422, 232 pp. fatalis is known from late Irvingtonian site. Russell W. Graham, Arthur H. Harris, Miller, G. J., 1968, On the age distribution of through late Rancholabrean sites (Kurtén and Jim I. Mead provided helpful com- Smilodon californicus Bovard from Rancho La and Anderson, 1980; Berta, 1985), so its ments on the manuscript. Brea: Natural History Museum of County, Contributions in Science, no. 131, 17 pp. presence does not help to limit the age of Miller, R. R., 1982, First fossil record (Plio– this site within the Rancholabrean. References Pleistocene) of threadfin shad, Dorosoma pete- Two other Pleistocene sites are known nense, from the Gatuña Formation of southeast- from ancestral Pecos River deposits in Berta, A., 1985, The status of Smilodon in North and ern New Mexico: Journal of Paleontology, v. 56, : Natural History Museum of Los pp. 423–425. southeastern Eddy County, not far north of Angeles County, Contributions in Science, no. the 25 Mile Stream site. The Nash Draw Morgan, G. S., Lucas, S. G., Sealey, P. L., and Hunt, 370, pp. 1–15. A. P., 2001, A review of Pleistocene vertebrate fauna (Harris, 1993) from Nash Draw, a Graham, R. W., 1987, Late mammalian faunas from northeastern New Mexico; in Lucas, tributary of the Pecos River, contains two faunas and paleoenvironments of the southwest- S. G., and Ulmer-Scholle, D. S. (eds.), Geology of species of Equus and the camel Camelops. ern plains of the United States; in Graham, R. W., the Llano Estacado: New Mexico Geological Semken, H. A., Jr., and Graham, M. A. (eds.), Late The threadfin shad, Dorosoma petenense, Society, Guidebook 52, pp. 265–284. Quaternary mammalian biogeography and envi- Stock, C., and Harris, J. M., 1992, Rancho La Brea— was reported from the type locality of the ronments of the and Prairies: Illinois Gatuña Formation in the Pecos River val- a record of Pleistocene life in California, 7th edi- State Museum Scientific Papers, v. 22, pp. 24–86. tion: Natural History Museum of Los Angeles ley near Loving (Miller, 1982). The age of Harris, A. H., 1985, Late Pleistocene vertebrate County, Science Series, no. 37, 113 pp. these two faunas is unclear because they paleoecology of the West: University of Texas Vanderhill, J. B., 1986, Lithostratigraphy, vertebrate lack age-diagnostic mammals, although Press, Austin, 293 pp. paleontology, and magnetostratigraphy of Plio– Harris, A. H., 1993, Quaternary vertebrates of New Pleistocene sediments in the Mesilla Basin, New both are presumed to be Pleistocene. Mexico; in Lucas, S. G., and Zidek, J. (eds.), The best documented Pleistocene verte- Mexico: Unpublished Ph.D. dissertation, Univer- Vertebrate paleontology in New Mexico: New sity of Texas (Austin), 305 pp. brate fauna from ancestral Pecos River Mexico Museum of Natural History and Science, Winans, M. C., 1989, A quantitative study of North deposits is the Roswell fauna, collected Bulletin 2, pp. 179–197. American fossil species of the genus Equus; in from a series of gravel pits on the east side Harris, A. H., and Porter, L. S. W., 1980, Late Prothero, D. R., and Schoch, R. M. (eds.), The evo- of the Pecos River northeast of Roswell, Pleistocene horses of Dry Cave, Eddy County, lution of perissodactyls: Oxford University Press, New Mexico: Journal of Mammalogy, v. 61, pp. New York, pp. 262–297. approximately 200 km (125 mi) north of 46–65. the 25 Mile Stream site (Lucas and Morgan,

November 2001 NEW MEXICO GEOLOGY 133