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Volume 27.1
January–April 2024
Full table of contents
ISSN: 1094-8074, web version;
1935-3952, print version
Recent Research Articles
See all articles in 27.1 January-April 2024
See all articles in 26.3 September-December 2023
See all articles in 26.2 May-August 2023
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Paul C. Murphey. Research Associate, Department of Paleontology, San Diego Museum of Natural History, 1788 El Prado, San Diego, California 92101, USA, pmurphey@sdnhm.org
Paul Murphey received a doctorate in geological sciences with an emphasis in vertebrate paleontology from the University of Colorado at Boulder in 2001. His professional experience includes appointments as the Collections Manager of Paleontology, Geology and Osteology in the Geology Section of the University of Colorado Museum; instructor in the Museum and Field Studies Program at the University of Colorado Museum; and graduate faculty member in the Department of Geological Sciences at the University of Colorado. He was an Associate Curator in the Department of Paleontology and the Associate Director of the Department of PaleoServices at the San Diego Natural History Museum. Dr. Murphey has been working as a consultant and Principal Investigator for paleontological resource impact mitigation projects throughout the United States for approximately 22 years. He was the Principal Paleontologist of the Paleontological Resources Program at SWCA Environmental Consultants for 11 years. In 2014, he joined Los Angeles–based Paleo Solutions as a partner and Vice President, forming Denver-based Rocky Mountain Paleo Solutions. Dr. Murphey is currently a research associate in the Department of Earth Sciences at the Denver Museum of Nature and Science and the Department of Paleontology at the San Diego Natural History Museum. His research is focused on the evolutionary history, stratigraphy, biochronology, and depositional environments of Paleogene fossil mammals and associated rock units in the Rocky Mountain region and southern California.
Thomas S. Kelly. Research Associate, Vertebrate Paleontology Department, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, California, USA, 90007, tom@tskelly.gardnerville.nv.us
Thomas Kelly received his B.A. and M.S. degrees in Biology from the California State University at Northridge (1968 and 1969) and a doctorate in Veterinary Medicine (DVM) from the University of California at Davis (1973). He did postgraduate research concentrating on the phylogenetic systematics of heteromyid rodents at the University of California, Davis in 1973-74. Since 1988, he has been a Research Associate in the Vertebrate Paleontology Department at the Natural History Museum of Los Angeles County and has been working as a consultant for paleontological resource impact mitigation projects in California for the last 25 years. He has published 52 paleontological articles, 39 of which were in peer-reviewed scientific journals. He has been the author or co-author of a number of new taxa in the paleontological literature, including nine mammal genera, 33 mammal species and one fish species. His interests are primarily in mammalian systematics and biostratigraphy.
FIGURE 1. Schematic stratigraphic column of type section Turtle Bluff Member on southwest flank of Cedar Mountain, Bridger Formation, showing relative stratigraphic positions of SDSNH, DMNS and UCM localities (along with the locality names in parentheses) that yielded the fossils described in this paper (reproduced from Kelly and Murphey, 2016a, figure 1). MPM Locality 2970 occurs on southwest flank of Sage Creek Mountain, and its approximate relative stratigraphic position is projected onto type section. Abbreviations are: Lithostr., lithostratigraphic; NALMA, North American Land Mammal age.
FIGURE 2. Apatemyidae from TBM. 1-6, Apatemys bellulus: RM1, UCM 70967 (1); Lm1, UCM 95804 (2); Lm2, UCM 68923 (3); partial Rm3, UCM 68424 (4); Lm3, UCM 95807 (5); Rm3, UCM 70676 (6). 7-12, Apatemys rodens: LM1, UCM 68580 (7); LM3, SDSNH 110342 (8); LM3, UCM 68970 (9); Rm3, UCM 95805 (10); partial Lm3, UCM 66324 (11). Rm3, 95801 (12). All occlusal views. Scale bar equals 1 mm.
FIGURE 3. Sespedectidae from TBM. 1-8, Scenopagus curtidens: LM1 (UCM 68966) in occlusal view (1); Ldp4 (UCM 110344) in occlusal (2) and labial (3) views; Lm1 or 2 (UCM 95685) in occlusal (4) and labial (5) views; Rm1 or 2 (UCM 95684) in occlusal (6) and labial (7) views; partial Rm3 (UCM 68968) in occlusal view (8). 9-11, Scenopagus priscus: Rm1 or 2 (UCM 95683) in occlusal (9) and labial (10) views; Rm3 (SDSNH 110345) in occlusal view (11). 12-13, Sespedectidae, genus undetermined, partial Lm1 or 2 (SDSNH 110343) in labial (12) and occlusal (13) views. Scale bar equals 1 mm.
FIGURE 4. Entomolestes westgatei new species from TBM. 1-2, partial dentary with Lp4-m1 (UCM 95687, holotype) in labial (1) and occlusal (2) views. 3-5, partial dentary with partial Rm1 and m2-3 (UCM 67884) in occlusal (3), labial (4), and lingual (5) views. Scale bar equals 1 mm.
FIGURE 5. Entomolestes westgatei new species from TBM. Specimens showing position of mental foramen (MF) and alveoli for antemolars anterior of p4. See text for proposed alveolar homologies. 1-2, partial dentary with Lp4-m1 (UCM 95686, m1 not shown) in occlusal (1) and labial (2) views. 3-4, partial dentary with Lp4-m1 (UCM 95687, holotype, m1 not shown) in occlusal (3) and labial (4) views. Scale bar equals 1 mm.
FIGURE 6. Geolabididae from TBM. 1-4, Centetodon bembicophagus: LP4 (UCM 68681) in occlusal view (1); partial Lm1 or 2 (UCM 68899) in occlusal view (2); Lm1 or 2 (DMNH 75256) in occlusal view (3); Lm3 (DMNH 75257) in occlusal view (4). 5-10, Centetodon pulcher: partial dentary with Lp4-m1 (UCM 95767) in occlusal (5) and labial (6) views; Rm1 or 2 (UCM 95768) in occlusal view (7); partial dentary with Lp1 and p4-m3 (UCM 68963) in occlusal (8), labial (9), and lingual (10) views. Scale bar equals 1 mm.
FIGURE 7. Nyctitherium gunnelli new species from TBM, associated Lp4-m2 (SDSNH 110393, holotype): Lp4 in occlusal (1), labial (4), and lingual (7) views; Lm1 in occlusal (2), labial (5), and lingual (8) views; Lm2 in occlusal (3), labial (6), and lingual (9) views. Scale bar equals 1 mm.
FIGURE 8. Nyctitheriidae from TBM. 1-6, Nyctitherium velox: RM2 (DMNH 75292) in occlusal view (1); RM2 (UCM 95771) in occlusal view (2); RM2 (UCM 68581) in occlusal view (3); RM3 (DMNH 75291) in occlusal view (4); partial Lm2 (DMNH 75317) in occlusal view (5); partial Lm2 (SDSNH 110409) in occlusal view (6). (7), Pontifactor bestiola, RM1 (UCM 71129) in occlusal view. 8-10, Nyctitherium gunnelli new species, LP4 (UCM 95769) in occlusal (8), labial (9), and lingual (10) views. Scale bar equals 1 mm.
FIGURE 9. Chart comparing m1-2 anteroposterior length (ap) versus m1-2 talonid width (trp) in mm of specimens of Nyctitherium velox (including two referred specimens from TBM, SDSNH 110409 and UCM 68967) and holotype m1-2 (SDSNH 110393) of Nyctitherium gunnelli new species. Black solid filled squares/circles are m1s and white filled squares/circles are m2s. Except for SDSNH 110409 and UCM 68967, measurements of other specimens of N. velox from Robinson (1968a) and Krishtalka (1976b).
FIGURE 10. Oligoryctidae and unnamed lipotyphlan from TBM. 1-4, unnamed apternodontid sp.: partial LM1 or 2 (SDSNH 110348) in occlusal (1) and anterior (2) views; partial Rm1 or 2 (SDSNH 110349) in occlusal (3) and labial (4) views. 5-6, unnamed lipotyphlan sp., partial dentary with Rp4 (DMNH 75258) in occlusal (5) and labial (6) views. Scale bars equals 1 mm.
FIGURE 11. Carnivoramorpha and Condylartha from TBM. 1, Viverravus gracilis, LM2 (UCM 95809). 2-3, Hyposodus lepidus: RM1 or 2, UCM 67958 (2); Rm1 or 2, UCM 67956 (3). All occlusal views. Scale bar = 1 mm.
FIGURE 12. Dinocerata and Perissodactyla from TBM. 1-3, Uintatherium anceps: Lp2, (DMNH 75310) in occlusal view (1); RP3 or 4 (DMNH 75308) in occlusal view (2); Lm2 (DMNH 75309) in occlusal view (3). 4-10, Wickia sp., cf. W. brevirhinus: LC (DMNH 75306) in labial view (4); RI3 (DMNH 75312) in lingual view (5); RP2 (DMNH 75311) in occlusal view (6); LM1 (DMNH 75305) in occlusal view (7); RM3 (DMNH 75304) in occlusal view (8); partial Lp4? (DMNH 75314) in occlusal view (9); Lm1 (DMNH 75307) in occlusal view (10). Scale bar equals 10 mm.
FIGURE 13. Perissodactyla from TBM. 1-4, Triplopus sp., cf. T. obliquidens, partial left dentary with alveolus for p1, p2, partial p3, p4 and partial m1 (UCM 69053 with 1, 3-4 original specimen, 2 cast showing detail better) in occlusal (1-2), labial (3) and lingual (4) views. 5-6, Epihippus sp., cf . E. gracilis, Rp3 (SDSNH 110408) in occlusal (5) and lingual (6) views. Scale bars for 1-2 and 3-4 equals 5 mm. Scale bar for 5-6 equals 1 mm.
FIGURE 14. Homacodon sp., cf. H. vagans from TBM. Partial Rp3 (UCM 95810) in occlusal (1), lingual (2), and labial (3) views. Scale bar equals 1 mm.
FIGURE 15. Merycobunodon? walshi new species from TBM. RM1 or 2 (UCM 67888, holotype, with 1 original specimen, 2-4 cast showing detail better) in occlusal (1-2), posterior (3), and anterior (4) views. Scale bar equals 1 mm.
TABLE 1. Measurements (in mm) of Apatemyidae from TBM. Abbreviations are: ap = greatest anteroposterior length; b = broken dimension; p. = partial; tr = greatest transverse width; tra = anterior transverse (trigonid) width; trp = posterior transverse (talonid) width.
Taxon/Specimen number | Position | ap | tr | tra | trp |
Apatemys bellulus | |||||
UCM 70967 | M1 | 1.96 | 1.90 | - | - |
UCM 95804 | m1 | 1.87 | - | 1.08 | 1.13 |
UCM 68923 | m2 | 1.85 | - | 1.39 | 1.31 |
UCM 68424 | p. m3 | 1.97 | - | - | 1.21 |
UCM 70676 | m3 | 1.92 | - | 1.23 | 1.05 |
UCM 95807 | m3 | 2.00 | - | 1.26 | 1.16 |
Apatemys rodens | |||||
UCM 68580 | M1 | 2.48 | 2.08 | - | - |
UCM 68970 | M3 | 1.36 | 2.37 | - | - |
SDSNH 110342 | p. M3 | 1.37b | 2.06b | - | - |
UCM 66324 | p. m3 | 2.79 | - | - | 1.74 |
UCM 95801 | p. m3 | 2.90 | - | - | 1.80 |
UCM 95805 | m3 | 2.82 | - | 2.13 | 1.74 |
TABLE 2. Measurements (in mm) of Lipotyphla and Carnivoramorpha from TBM. Abbreviations are: ap = greatest anteroposterior length; b = broken dimension; p. = partial; tr = greatest transverse width; tra = anterior transverse (trigonid) width; trp = posterior transverse (talonid) width.
Taxon/Specimen number | Position | ap | tr | tra | trp |
Scenopagus priscus | |||||
UCM 95683 | m1 or 2 | 1.40 | - | 1.02b | 1.05 |
SDSNH 110345 | m3 | 1.35 | - | 0.85 | 0.67 |
Scenopagus curtidens | |||||
UCM 68966 | M1 | 1.77 | 2.49 | - | - |
SDSNH 110344 | dp4 | 1.60 | - | 0.91 | 1.00 |
UCM 70677 | p. m1 or 2 | 1.88 | - | 1.32 | - |
UCM 95684 | m1 or 2 | 1.80 | - | 1.49 | 1.51 |
UCM 95685 | m1 or 2 | 1.74 | - | 1.46 | 1.49 |
UCM 68968 | m3 | 1.60 | - | 1.12 | 0.94 |
Sespedectinae, genus undet. | |||||
SDSNH 110343 | p. m1 or 2 | 1.36b | - | 1.44 | - |
Entomolestes westgatei n. sp. | |||||
UCM 68540 | p4 | 0.90 | - | 0.67 | 0.62 |
UCM 95686 | p4 | 0.95 | - | 0.71 | 0.58 |
m1 | 1.56 | - | 0.93 | 0.95 | |
UCM 95687 (holotype) | p4 | 0.90 | - | 0.72 | 0.62 |
m1 | 1.59 | - | 0.94 | 0.95 | |
UCM 67884 | p. m1 | - | - | 0.90 | 0.88 |
m2 | 1.41 | - | 0.93 | 0.93 | |
m3 | 1.08 | - | 0.64 | 0.57 | |
UCM 78746 | p. m1 | - | - | 0.93 | - |
UCM 68423 | m2 | 1.39 | - | 0.91 | 0.93 |
UCM 68973 | m2 | 1.36 | - | 0.95 | 0.87 |
Centetodon bemicophagus | |||||
UCM 68681 | P4 | 1.46 | 1.49 | - | - |
SDSNH 110347 | M3 | 0.93 | 1.90 | - | - |
SDSNH 110391 | p4 | 1.21 | - | 0.67 | 0.67 |
UCM 68899 | m1 or 2 | 1.49 | - | 1.00 | 0.85 |
UCM 71128 | m1 or 2 | 1.34 | - | 0.77 | 0.70 |
DMNH 75256 | m1 or 2 | 1.50 | - | 0.85 | 0.70 |
DMNH 75257 | m3 | 1.46 | - | 0.85 | 0.70 |
Centetodon pulcher | |||||
UCM 67889 | p4 | 1.55 | - | 0.92 | 0.87 |
UCM 68534 | p4 | 1.59 | - | 0.93 | 0.87 |
UCM 95767 | p4 | 1.79 | - | 0.93 | 0.93 |
m1 | 2.01 | - | 1.28 | 1.18 | |
UCM 95768 | m1 or 2 | 1.83 | - | 1.25 | 1.16 |
UCM 68963 | p1 | 1.19 | 0.52 | - | - |
p4 | 1.59 | - | 1.10 | 0.93 | |
m1 | 1.75 | - | 1.31 | 1.20 | |
m2 | 1.70 | - | 1.21b | 1.15 | |
m3 | 1.68 | - | 1.10b | 0.90 | |
DMNH 75327 | m2 | 1.65 | - | 1.03 | 0.87 |
UCM 69968 | m3 | 1.55 | - | 1.03 | 0.93 |
UCM 95682 | m3 | 1.59 | - | 1.05 | 0.87 |
Nyctitherium gunnelli n. sp. | |||||
UCM 95769 | P4 | 2.08 | 2.54 | - | - |
SDSNH 110393 (holotype) | p4 | 2.09 | - | 0.93 | 1.00 |
m1 | 2.23 | - | 1.14 | 1.22 | |
m2 | 2.08 | - | 1.23 | 1.27 | |
Nyctitherium velox | |||||
DMNH 75292 | M2 | 1.71 | 2.27 | - | - |
UCM 68581 | M2 | 1.58 | 2.13 | - | - |
UCM 95771 | M2 | 1.62 | 2.11 | - | - |
DMNH 75290 | p. M1 or 2 | - | 2.10b | - | - |
DMNH 75291 | M3 | 1.21 | 1.90 | - | - |
UCM 68967 | m1 | 1.72 | - | 1.08 | 1.13 |
SDSNH 110409 | p. m2 | 1.60 | - | 1.13 | 1.18 |
DMNH 75317 | p. m2 | 1.74 | - | - | 1.23 |
UCM 67899 | p. m2 | 1.59b | - | - | 1.25 |
Pontifactor bestiola | |||||
UCM 71129 | M1 | 1.58 | 1.78 | - | - |
unnamed apternodontid sp. | |||||
SDSNH 110348 | p. M1 or 2 | 0.49b | 1.05b | - | - |
SDSNH 110349 | p. m1 or 2 | 0.79b | 0.63b | - | - |
unnamed lipotyphlan sp. | |||||
DMNH 75258 | p4 | 0.80 | - | 0.54 | 0.54 |
Viverravus gracilis | |||||
UCM 95809 | M2 | 2.60 | 4.15 | - | - |
TABLE 3. Measurements (in mm) of Hyopsodus sp., Uintatherium anceps, Wickia sp., cf. W. brevirhinus, Triplopus sp., cf. T. obliquidens, Epihippus sp., cf. E. gracilis, and Merycobunodon? walshi new species from TBM. Abbreviations are: ap = greatest anteroposterior length; b = broken dimension; p. = partial; tr = greatest transverse width; tra = anterior transverse (trigonid) width; trp = posterior transverse (talonid) width.
Taxon/Specimen number | Position | ap | tra | trp |
Hyopsodus lepidus | ||||
UCM 67956 | M1 or 2 | 3.92 | 4.97 | 4.67 |
UCM 67958 | m1 or 2 | 3.71 | 3.05 | 2.99 |
Uintatherium anceps | ||||
DMNH 75308 | P3 or 4 | 20.4 | 29.3 | 26.8 |
DMNH 75310 | p2 | 20.9 | 11.7 | 14.1 |
DMNH 75309 | m2 | 32.3 | 28.3 | 24.1 |
Wickia sp., cf. W. brevirhinus | ||||
DMNH 75312 | I3 | 21.8 | 22.3 | - |
DMNH 75306 | C | 21.2 | 18.1 | |
DMNH 75311 | P2 | 20.4 | 19.8 | - |
DMNH 75305 | M1 | 40.6 | 39.3 | - |
DMNH 75304 | M3 | 50.8 | 49.1 | - |
DMNH 75314 | p. p4 | - | - | 27.1 |
DMNH 75307 | m1 | 47.8 | 28.1 | 28.7 |
Triplopus sp., cf. T. obliquidens | ||||
UCM 69053 | p2 | 7.85 | 4.00 | 4.09 |
p3 | 9.94 | - | - | |
p4 | 10.55 | 6.52 | 7.38 | |
m1 | 13.10 | 8.15 | - | |
DMNH 75320 | p4 | 10.07 | 6.20 | 6.56 |
p. m2 | - | - | 8.52 | |
DMNH 75315 | m1 | 13.45 | 6.77 | 7.52 |
Epihippus sp., cf. E. gracilis | ||||
SDSNH 110408 | p3 | 7.40 | 4.35 | 4.70 |
Homacodon sp., cf. H. vagans | ||||
UCM 95810 | p. p3 | 3.36b | 1.51b | - |
Merycobunodon? walshi n. sp. | ||||
UCM 69053 (holotype) | M1 or 2 | 5.98 | 7.71 | 7.19 |
TABLE 4. Comparison of dental characters of M1 or 2 of Merycobunodon? walshi to the M1-2s of other middle Eocene oromeryicids and homacodonts (Mercobunodon littoralis, Protylopus stocki, Protylopus annectans, Protylopus pearsonensis, Oromeryx plicatus, Malaquiferus tourteloti, Helohyus milleri, Antiacodon pygmaeus, Homacodon vagans, Bunomeryx montanus, Hylomeryx annectans, Mytonomeryx scotti, Pentacemylus progressus, Mesomeryx grangeri and Apriculus praeteritus). Shared characters are shown in bold.
Taxon | Characters | |||||||
Mesostyle | Hypocone | Protoconule | Post- protocrista bifurcation |
Paracone & metacone ribs |
Enamel crenulation | Selenodonty (crescentic primary cusps) | Crown height | |
M.? walshi | present moderate | absent | ? | present | present - weak | present -weak | buno-selenodont | low |
M. littoralis | present moderate | absent | present | present | present - moderate | present moderate | buno-selenodont | low |
P. stocki | present strong | absent | absent | present | present - strong | present -moderate | moderate | moderate |
P. annectans | present strong | absent | absent | present | present - strong | present -moderate | moderate | moderate |
P. pearsonensis | present strong | absent | absent | present | present - strong | present -moderate | moderate | moderate |
O. plicatus | present strong | absent | absent | present | present - strong | present - heavy | moderate | moderate |
M. tourteloti | present strong | absent | absent | present | present - very strong | present - heavy | moderate | moderate |
H. milleri | incipient | present | present | absent | absent | absent | bunodont | low |
A. pygmaeus | absent | present | present | absent | absent | absent | bunodont | low |
H. vagans | absent | present | present | absent | absent | absent | bunodont | low |
B. montanus | present | present | present | absent | present -moderate | absent | moderate | moderate |
H. annectans | absent to incipient | present | present | absent | incipient | absent | moderate | moderate |
M. scotti | present strong | present | present | absent | present -strong | absent | moderate | moderate |
P. progressus | present strong | M1 vestigial M2 absent | present | absent | present -strong | present -moderate | moderate | moderate |
M. grangeri | absent | absent | present | absent | present -weak | absent | moderate | moderate |
A praeteritus | absent | absent | present | absent | absent | absent | bunodont | low |
TABLE 5. Taxa lists of mammals of Uintan biochron Ui1a from TBM and the basal Tertiary Conglomerate Local Fauna (BTC) of lower member of the Devil's Graveyard Formation, Texas, along with taxa from lower in Bridger Formation (Br2 or Br3) that are holdovers in the TBM and BTC, and taxa that range-through to Ui1b or later. Superscripts in the table indicate the reference numbers. References: 1, Leidy (1872b); 2, Marsh (1872b); 3, Matthew (1909); 4, Troxell (1923a); 5, Wilson (1937); 6, McKenna and Simpson (1959); 7, Wood (1959); 8, Wood (1973); 9, Robinson (1968a); 10, Szalay (1969); 11, Szalay (1976); 12, West (1974); 13, Gazin (1976); 14, Krishtalka (1976b); 15, Lillegraven et al. (1981); 16, West and Hutchinson (1981); 17, Wilson and Schiebout (1984); 18, West (1982); 19, Wilson (1984); 20, Wilson (1986); 21, Krishtalka, personal communication in Wilson (1986); 22, McCarroll et al. (1996); 23, Walsh (1996b); 24, Asher et al. (2002); 25, Turnbull (2002); 26, Williams and Kirk (2008); 27, Gunnell et al. (2008a); 28, Gunnell et al. (2009); 29, Mihlbachler (2008); 30, Murphey and Dunn (2009); 31, Campisano et al. (2014); 32, Kelly and Murphey (2016a); 33, this paper. FAD = first appearance datum. Index species = taxa restricted to Ui1a. N = number of taxa.
Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, USA, Part 2: Apatotheria, Lipotyphla, Carnivoramorpha, Condylartha, Dinocerata, Perissodactyla and Artiodactyla
Plain Language Abstract
The Turtle Bluff Member (TBM) of the Bridger Formation in southwestern Wyoming, formerly known as the Bridge E, is designated as the stratotype section for the earliest Uintan or biochron Ui1a of the Uintan North American Land Mammal age. The TBM overlies the Twin Buttes Member of the Bridger Formation, upon which the Twinbuttean Subage or biochron Br3 of the Bridgerian North American Land Mammal age is based. For over a century, the TBM yielded only a few fragmentary specimens, but extensive field work over the last 23 years has resulted in the discovery of numerous mammal fossils from the member, which provides an unprecedented opportunity to better define this poorly known interval. This is the second in a series of three papers that provides detailed descriptions and taxonomic revisions of the fauna from the TBM. Here we document the occurrence of 21 mammal species from the TBM: two species of the primitive insectivore-like mammal Apatemys; 11 species of 'insectivores' including two new species, Nyctitherium gunnelli and Entomolestes westgatei; the primitive carnivoran Viverravus gracilis; the small ungulate-like (condylarth) mammal Hyopsodus lepidus; the giant primitive ungulate Uintatherium anceps; the early brontothere (rhino-like) Wickia; the small rhino Triplopus; the small horse Epihippus; and two artiodactyls (the primitive Homacodon and a new species, Merycobunodon? walshi). A greater understanding of the faunal composition of the TBM allows a better characterization of the beginning of the Uintan and further clarifies the Bridgerian-Uintan transition.
Resumen en Español
Mamíferos del Miembro Turtle Bluff del Uintano más temprano (Eoceno medio), Formación Bridger, suroeste de Wyoming, EE.UU., Parte 2: Apatotheria, Lipotyphla, Carnivoramorpha, Condylartha, Dinocerata, Perissodactyla y Artiodactyla
El Miembro Turtle Bluff (TBM) de la Formación Bridger en el suroeste de Wyoming, anteriormente conocido como Bridger E, es designado como la sección estratotipo para el Uintano más temprano o biocrón Ui1a del Uintano como edad de Mamíferos Terrestres Norteamericanos. El TBM se encuentra sobre el Miembro Twin Buttes de la Formación Bridger, sobre el cual se caracteriza la subedad "Twinbuttean" o biocrón Br3 del Bridgeriano como edad de Mamíferos Terrestres Norteamericanos. Durante más de un siglo, el TBM produjo sólo unos pocos ejemplares fragmentarios, pero un extenso trabajo de campo realizado en los últimos 23 años ha supuesto el descubrimiento de numerosos fósiles de mamíferos del miembro, lo que proporciona una oportunidad sin precedentes para definir mejor este intervalo poco conocido. Este es el segundo de una serie de tres artículos que proporcionan descripciones detalladas y revisiones taxonómicas de la fauna del TBM. Aquí documentamos el hallazgo de los siguientes taxones del TBM: Apatemys bellulus; Apatemys rodens; Scenopagus priscus; Scenopagus curtidens; Sespedectinae, género indeterminado; Entomolestes westgatei nov. sp.; Centetodon bemicophagus; Centetodon pulcher; Nyctitherium gunnelli nov. sp.; Nyctitherium velox; Pontifactor bestiola; un Oligoryctidae sin nombre asignado por ahora; un Lipotyphla sin nombre asignado por ahora; Viverravus gracilis; Hyopsodus lepidus; Uintatherium anceps; Wickia sp., cf. W. brevirhinus; Triplopus sp., cf. T. obliquidens; Epihippus sp., cf. E. gracilis; Homacodon sp., cf. H. vagans; y Merycobunodon? walshi nov. sp. Un mayor conocimiento de la composición faunística del TBM permite una mejor caracterización del comienzo del Uintano y aclara aún más la transición Bridgeriano-Uintano.
Palabras clave: bioestratigrafía, Eoceno; mamíferos; nuevas especies; Uintano
Traducción: Enrique Peñalver (Sociedad Española de Paleontología)
Résumé en Français
Mammifères de l'Uintien basal (Éocène moyen) du membre Turtle Bluff, formation de Bridger, sud-ouest du Wyoming, États-Unis, 2ème partie : Apatotheria, Lipotyphla, Carnivoramorpha, Condylarthra, Dinocerata, Perissodactyla, et Artiodactyla
Le membre Turtle Bluff (TBM) de la formation de Bridger dans le sud-ouest du Wyoming, précédemment connu sous le nom de « Bridger E », est désigné comme la section stratotype de l'Uintien basal ou le biochrone Ui1a de l'âge Uintien de l'échelle chronostratigraphique des mammifères terrestres d'Amérique du Nord (NALMA). Le TBM recouvre le membre Twin Buttes de la formation de Bridger, membre d'après lequel le sous-âge « Twinbuttean » ou biochrone Br3 de l'âge Bridgérien NALMA est caractérisé. Pendant plus d'un siècle, le TBM n'a livré que quelques spécimens fragmentaires, mais un travail de terrain approfondi pendant ces 23 dernières années a entrainé la découverte de nombreux fossiles de mammifères dans ce membre, ce qui fournit une opportunité sans précédent de mieux définir cet intervalle peu connu. Dans la deuxième partie d'une série de trois papiers, nous fournissons des descriptions détaillées et des révisions taxinomiques de la faune du TBM. Nous documentons ici les occurrences des taxons suivants dans le TBM : Apatemys bellulus ; Apatemys rodens ; Scenopagus priscus ; Scenopagus curtidens ; Sespedectinae gen. indet. ; Entomolestes westgatei sp. nov. ; Centetodon bemicophagus ; Centetodon pulcher ; Nyctitherium gunnelli sp. nov. ; Nyctitherium velox ; Pontifactor bestiola ; un oligoryctidé non nommé ; un Lipotyphla non nommé ; Viverravus gracilis ; Hyopsodus lepidus ; Uintatherium anceps ; Wickia sp., cf. W. brevirhinus ; Triplopus sp., cf. T. obliquidens ; Epihippus sp., cf. E. gracilis ; Homacodon sp., cf. H. vagans ; et Merycobunodon? walshi sp. nov. Une compréhension approfondie de la composition faunique du TBM permet une meilleure caractérisation du début de l'Uintien et éclaircit la transition Bridgérien-Uintien.
Mots-clés : biostratigraphie ; Éocène ; mammifères ; nouvelle espèce ; Uintien
Translator: Antoine Souron
Deutsche Zusammenfassung
Säugetiere aus dem frühesten Uintum (mittleres Eozän) Turtle Bluff Member, Bridger Formation, südwestliches Wyoming, USA, Teil 2: Apatotheria, Lipotyphla, Carnivoramorpha, Condylartha, Dinocerata, Perissodactyla und Artiodactyla
Das Turtle Bluff Member (TBM) der Bridger Formation im südwestlichen Wyoming, das früher als Bridger E bekannt war, wird als Stratotyp-Sektion für das früheste Uintum oder Biochron Ui1a der Uintum Nordamerikanischen Landsäugetier Stufe ausgewiesen. Das TBM überlagert das Twin Buttes Member der Bridger Formation, auf der die Twinbuttean Substufe oder Biochrone BR3 der bridgerischen Nordamerikanischen Landsäugetierstufe charakterisiert ist. Über ein Jahrhundert lieferte die TBM nur ein paar fragmentarische Stücke, jedoch führte eine umfassende Geländearbeit in den letzten 23 Jahren zu zahlreichen fossilen Säugetierfunden und lieferte damit eine unerwartete Möglichkeit dieses kaum bekannte Intervall besser zu definieren. Dies ist die zweite Veröffentlichung einer Serie, die detaillierte Beschreibungen und taxonomische Revisionen der TBM-Fauna zur Verfügung stellt. Hier dokumentieren wir das Vorkommen folgender Taxa aus der TBM: Apatemys bellulus; Apatemys rodens; Scenopagus priscus; Scenopagus curtidens; Sespedectinae, Gattung unbestimmt; Entomolestes westgatei neue Art; Centetodon bemicophagus; Centetodon pulcher; Nyctitherium gunnelli new species; Nyctitherium velox; Pontifactor bestiola; ein unbenannter Oligoryctide; ein unbenannter Lipotyphlane; Viverravus gracilis; Hyopsodus lepidus; Uintatherium anceps; Wickia sp., cf. W. brevirhinus; Triplopus sp., cf. T. obliquidens; Epihippus sp., cf. E. gracilis; Homacodon sp., cf. H. vagans; and Merycobunodon? walshi neue Art. Ein tieferes Verständnis der Faunenzusammensetzung der TBM erlaubt eine bessere Charakterisierung des Beginns des Uintums und klärt außerdem den Bridger-Uintum Übergang.
Schlüsselwörter: Biostratigraphie, Eozän; Säugetiere; neue Art; Uintum
Translator: Eva Gebauer
Arabic
Translator: Ashraf M.T. Elewa
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Review: The Princeton Field Guide to Mesozoic Sea Reptiles
The Princeton Field Guide to Mesozoic Sea Reptiles
Article number: 26.1.1R
April 2023 -