Figure 1.
Satellite image of the Devil’s Graveyard Formation study area and surrounding region.
WSQ = Whistler Squat Quarry; JCT = Junction locality; AF = Agua Fria Mountain; HE = Hen Egg Mountain; DB = Devil’s Graveyard basalt; DM = Dogie Mountain.
Figure 2.
Lithostratigraphy, biochronology and radiometric ages of the Devil’s Graveyard Formation in the Agua Fria and Hen Egg Mountain region.
Sample numbers for dated horizons are in parentheses. The 1980s K/Ar age for sample B-5367 of 42.7±1.6 Ma [8], [14] has been assumed to be erroneously old by others (e.g., [96]) and is being redated. Locality numbers: Hen Egg Mountain (TMM 42028, TMM 42287); 0.6 miles east of Junction (TMM 41444); Junction (TMM 41443); Boneanza (TMM 41747); Wax Camp (TMM 41576); Whistler Squat Quarry (TMM 41372); 300 yd east of Whistler Squat Quarry (TMM 41466); Titanothere Hill (TMM 41723); Serendipity (41745); Purple Bench (TMM 41672); Tepee Canyon (TMM 41578); Above Skyline (TMM 41580); Dalquest’s Canyon (TMM 41715).
Figure 3.
Photos of the Whistler Squat Quarry locality.
From the archives of the Vertebrate Paleontology Laboratory and courtesy of Sarah Wilson. A, 1970 aerial view of the locality prior to any significant quarrying with key features marked; B, excavation at the quarry, July 1971; C, close-up of the ∼20 cm fossiliferous horizon immediately overlying the Quarry Tuff, August 1971.
Figure 4.
40Ar/39Ar age distribution of JW-1 phenocrysts.
Age-probability density function and weighted-mean age of the 40Ar/39Ar single-crystal total-fusion (SCTF) analyses of individual sanidine phenocrysts from sample JW-1. Complete analytical data provided in Table S1.
Table 1.
Summary single-crystal total-fusion 40Ar/39Ar analytical results for JW-1 sanidine phenocrysts.
Figure 5.
40Ar/39Ar incremental heating spectra of JW-2 phenocrysts.
Spectra derived from 40Ar/39Ar single-crystal incremental-heating (SCIH) analyses of individual biotite phenocrysts from sample JW-2. Excludes steps yielding less than 2% of the total 39Ar released. Complete analytical data provided in Table S1.
Figure 6.
40Ar/39Ar age distribution of JW-2 phenocrysts.
Age-probability density function and weighted-mean age of the plateau ages from the single-grain biotite 40Ar/39Ar SCIH analyses. Complete analytical data provided in Table S1.
Table 2.
Summary single-crystal incremental-heating 40Ar/39Ar analytical results for JW-2 biotite phenocrysts.
Figure 7.
Select dental specimens from the Whistler Squat local fauna.
A–B, Herpetotherium sp., left m1/2 (TMM 41372-403), lingual view (A) and occlusal view (B); C, Scenopagus cf. S. edenensis, right mandibular molar (TMM 41372-118), occlusal view; D, Microsyops annectens, partial right maxilla with P4-M3 (TMM 41466-7), occlusal view; E, Ourayia uintensis, right m2 trigonid (TMM 41372-301), occlusal view.
Figure 8.
Select rodent dental specimens from the Whistler Squat local fauna.
A–H, Thisbemys plicatus, (A) right m1 (TMM 41372-25), (B) right M3 (TMM 41372-56), (C) left M3 (TMM 41372-129), (D) right P4 (TMM 41372-270), (E) left m3 (TMM 41372-130), (F) right m2 (TMM 41372-131), (G) left m3 (TMM 41372-117), (H) left M2 (TMM 41372-135); I–J, Microparamys minutus, (I) right p4 (TMM 41372-298); J, left m1/2 (TMM 41372-260); K, Microparamyinae gen. et sp. indet., left m3 (TMM 41372-286); L–S, Mysops boskeyi, (L) left M1 (TMM 41372-141), (M) left m2 (TMM 41372-250), (N) left m3 (TMM 41372-253), (O) right m3 (TMM 41372-258), (P) left M2 (TMM 41372-290), (Q) right M1 (TMM 41372-307), (R) left M1 (TMM 41372-144), (S) right m1 (TMM 41372-293); T–Y, Prolapsus sibilatoris, (T) partial right mandible with m1–3, holotype (TMM 41372-179), (U) left M1 (TMM 41372-300), (V) left M1 (TMM 41372-256), (W) right M1 (TMM 41372-285), (X) right m1 (TMM 41372-291), (Y) right m3 (TMM 41372-265); Z, Pauromys texensis, right M2 (TMM 41372-279). All occlusal views.
Figure 9.
Select dental specimens from the Whistler Squat local fauna.
A, Hyopsodus sp., right M2 (TMM 41372-227), occlusal view; B–C, Helohyus sp., left m1/2 (TMM 41446-12), buccal view (B) and occlusal view (C).
Figure 10.
Select Leptoreodon marshi specimens from the Whistler Squat local fauna.
A, left maxilla with C–P3, M1–3 (TMM 41372-175), occlusal view; B, left mandible with dp2–dp4, m1–m2 (TMM 41372-176), oblique occlusal view and C, buccal view; D, right mandible with p2–m3 (TMM 41372-178), oblique occlusal view and E, lingual view.
Figure 11.
Select specimens from the Whistler Squat local fauna.
A, Leptoreodon major, partial right maxilla with M1 crown base and M2-M3 (TMM 41466-2), occlusal view; B–C, Protitanotherium emarginatum, (B) right p2 (TMM 41372-536), occlusal view, (C) left M2 (TMM 41466-6), occlusal view; D, Equidae gen. et sp. indet., right astragalus (TMM 41372-204), superior view.
Figure 12.
Select Amynodon advenus specimens from the Whistler Squat local fauna.
A, partial left maxilla with C–M3 (TMM 41372-45), occlusal view; B, partial left maxilla with P4–M3 (TMM 41372-72), occlusal view; C, partial left mandible with p3–m3 (TMM 41372-99), buccal view and D, occlusal view.
Figure 13.
Select dental specimens from the Whistler Squat local fauna.
A-B, Sinopa major, partial left mandible with m1–m2 (TMM 41466-9), buccal view (A) and occlusal view (B); C–E, Miacidae gen. et sp. indet., partial left P4 (TMM 41372-389), lingual view (C), buccal view (D), and occlusal view (E); F–H, Miocyon sp., left p4 (TMM 41372-367), buccal view (F), lingual view (G), and occlusal view (H).
Figure 14.
Whistler Squat faunal list and associated Bridgerian and Uintan biochronological zone ranges.
Mammalian taxa identified from Whistler Squat local fauna localities TMM-41372 and TMM-41466 and their Bridgerian (Br) and Uintan (Ui) biochronological zone ranges based on Wilson [7], Wilson and Runkel [51], Walton [60], Williams and Kirk [12], Robinson [1], Gunnell et al. [2], and this study. Gray bars indicate range extension of non-endemic taxa compared to Robinson et al. [1] and Gunnell et al. [2]. 1Herpetotherium species candidates range throughout the Bridgerian and Uintan, 2Range listed is for S. edenensis, 3Endemic species, but extends LRD of genus from Ui3. 4Endemic species, but extends HRD of genus from Ui1a. 5Range is genus/species specific. 6Extends LRD of genus from Ui2.