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.