FIGURE 1. Simplified map of Montana, North Dakota, South Dakota, and Wyoming, USA, illustrating the known county distribution of Axestemys infernalis sp. nov. in the Late Cretaceous (Maastrichtian) Hell Creek and Lance formations. Outcrops of the Hell Creek and stratigraphically equivalent Lance Creek, Scollard, and Frenchman formations are highlighted in grey. Abbreviations: D = Dawson County; G = Garfield County; H = Harding County; M = McCone County; N = Niobrara County; S = Slope County.
FIGURE 2. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Bonebed locality of Harding County, South Dakota, USA. Photograph and line drawings of TMP 2009.24.10, a carapace, in (1) dorsal and (2) ventral views. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural.
FIGURE 3. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Bonebed locality of Harding County, South Dakota, USA. Photograph and line drawings of TMP 2009.24.137, a carapace, in (1) dorsal and (2) ventral views. Abbreviations: co = costal; ent = entoplastron; il = ilium; is = ischium; ne = neural; nu = nuchal; pu = pubis; pn = preneural; sc = scapula.
FIGURE 4. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Bonebed locality of Harding County, South Dakota, USA. Photograph and line drawings of (1) TMP 2009.24.4, a carapace, and (2) TMP 2009.24.105, a partial carapace, in dorsal view. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural.
FIGURE 5. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Bonebed locality of Harding County, South Dakota, USA. Photographs of (1) TMP 2009.24.75, right epiplastron, in ventral and dorsal views; (2) TMP 2009.24.73, right epiplastron, in ventral and dorsal views; (3) TMP 2009.24.72, right epiplastron, in ventral and dorsal views; (4) TMP 2009.24.16, right epiplastron, in ventral and dorsal views; (5) TMP 2009.24.51, left epiplastron and entoplastron, in dorsal and ventral views; (6) TMP 2009.24.52, entoplastron, in dorsal and ventral views; (7) TMP 2009.24.56, entoplastron, in dorsal and ventral views; (8) TMP 2009.24.93, left hyoplastron, in dorsal and ventral views; (9) TMP 2009.24.97, right hyoplastron, in ventral and dorsal views; (10) TMP 2009.24.98, right hyo/hypoplastron, in ventral and dorsal views; (11) TMP 2009.24.44, right hyo/hypoplastron, in ventral and dorsal views; (12) TMP 2009.24.95, left hyo/hypoplastron, in dorsal and ventral views; (13) TMP 2009.24.101, right hyo/hypoplastron, in ventral and dorsal views; (14) TMP 2009.24.48, left hyo/hypoplastron, in dorsal and ventral views; (15) TMP 2009.24.80, right xiphiplastron, in ventral and dorsal views; (16) TMP 2009.24.54, right xiphiplastron, in ventral and dorsal views; (17) TMP 2009.24.55, right xiphiplastron, in ventral and dorsal views; (18) TMP 2009.24.47, right xiphiplastron, in ventral and dorsal views; (19) TMP 2009.24.125, right xiphiplastron, in ventral and dorsal views; (20) TMP 2009.24.43, right xiphiplastron, in ventral and dorsal views; (21) TMP 2009.24.46, right xiphiplastron, in ventral and dorsal views; (22) TMP 2009.24.42, left xiphiplastron, in dorsal and ventral views; (23) TMP 2009.24.81, left xiphiplastron, in dorsal and ventral views. See Figure 6 for line drawings of these specimens.
FIGURE 6. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Bonebed locality of Harding County, South Dakota, USA. Line drawings of specimens depicted in Figure 5.
FIGURE 7. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Big Turtle Cove locality of Slope County, North Dakota, USA. Photographs of (1) DMNH 131100, holotype, partial carapace in dorsal and ventral views; (2) DMNH 130958, costal VI in dorsal and ventral views; (3) DMNH 130949, preneural in dorsal and ventral views; (4) DMNH 130957, costal I in dorsal and ventral views; (5) DMNH 130948, neural in dorsal and ventral views; (6) DMNH 97045, posterior two thirds of carapace in dorsal and ventral views; (7) DMNH 130942, dorsal vertebra I in dorsal and ventral views. See Figure 8 for line drawings of these specimens.
FIGURE 8. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Big Turtle Cove locality of Slope County, North Dakota, USA. Line drawings of specimens depicted in Figure 7. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural.
FIGURE 9. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Big Turtle Cove locality of Slope County, North Dakota, USA. Photographs and line drawings of (1) DMNH 97093, a nearly complete carapace in dorsal view; (2) DMNH 130959, right hyoplastron in ventral and dorsal views; (3) DMNH 130963, left hyoplastron in ventral and dorsal views; (4) DMNH 130964, right hyoplastron in ventral and dorsal views; (5) DMNH 130956, right hypoplastron in ventral and dorsal views; (6) DMNH 130954, left hyo/hypoplastron in ventral and dorsal views; (7) DMNH 130951, cranium in dorsal and ventral views; (8) DMNH 130952, mandible in dorsal view; (9) DMNH 130947, ungual phalanx in dorsal and palmar views; (10) DMNH 130955, right pelvis in dorsal view; (11) DMNH 130943, right partial scapulocoracoid in medial view; (12) DMNH 130953, left humerus in dorsal and ventral views; (13) DMNH 130945, right humerus in ventral and dorsal views; (14) DMNH 130950, right femur in dorsal and ventral views; (15) DMNH 130946, left femur in dorsal and ventral views. Abbreviations: co = costal; hyo = hyoplastron; hyp = hypoplastron; ne = neural; nu = nuchal; pn = preneural.
FIGURE 10. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Ridge locality of Slope County, North Dakota, USA. Photographs and line drawings of (1) DMNH 98825, a nuchal, in dorsal view; (2) DMNH 97037, anterior portions of carapace, in dorsal view; (3) DMNH 98809, parts of left costal I and II, in dorsal view; (4) DMNH 98824, right costal IV in dorsal view; (5) DMNH 98831, right costal V, in dorsal view; (6) DMNH 97027, anterior portions of carapace, in dorsal view; (7) DMNH 98814, a partial cranium, in dorsal view; (8) DMNH 97038, right hyo/hypoplastron in ventral and dorsal views; (9) DMNH 98863, left hyoplastron in dorsal and ventral views. Abbreviations: co = costal; hyo = hyoplastron; hyp = hypoplastron; ne = neural; nu = nuchal; pn = preneural.
FIGURE 11. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Graveyard locality of Slope County, North Dakota, USA. Photographs of (1) DMNH 97021, nuchal in dorsal and ventral views; (2) DMNH 130931, anterior portions of carapace in dorsal and ventral views; (3) DMNH 125911, left costal V in dorsal and ventral views; (4) DMNH 130934, right costal IV in dorsal and ventral views; (5) DMNH 130932, right costal V in dorsal and ventral views; (6) DMNH 96955, right costal VI in dorsal and ventral views; (7) DMNH 130935, right costal VI and VII in dorsal and ventral views; (8) DMNH 96928, partial mandible in dorsal view; (9) DMNH 125912, partial entoplastron in ventral and dorsal views; (10) DMNH 130927, right hyo/hypoplastron in ventral and dorsal views; (11) DMNH 130929, left hyoplastron in ventral and dorsal views; (12) DMNH 125919, left hypoplastron in ventral and dorsal views; (13) DMNH 125913, right xiphiplastron in ventral and dorsal views; (15) DMNH 125914, left xiphiplastron in ventral and dorsal views. See Figure 12 for line drawings of these specimens.
FIGURE 12. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) Turtle Graveyard locality of Slope County, North Dakota, USA. Line drawings of specimens depicted in Figure 11. Abbreviations: co = costal; hyo = hyoplastron; hyp = hypoplastron; ne = neural; nu = nuchal; pn = preneural; xi = xiphiplastron.
FIGURE 13. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) of Dawson County, Montana, USA. Photograph and line drawings of AMNH 14149, a partial carapace, in dorsal view. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural. Photograph courtesy of Division of Paleontology, AMNH, New York.
FIGURE 14. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) of Garfield County, Montana, USA. Photograph and line drawings of LACM 15432 in (1) dorsal and (2) ventral views. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural. Photograph courtesy of the Dinosaur Institute, LACM, Los Angeles.
FIGURE 15. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) of McCone County, Montana, USA. Photograph and line drawings of RAM 9393 in (1) dorsal and (2) ventral views. Abbreviations: co = costal; ne = neural; nu = nuchal; pn = preneural. Photograph courtesy of the RAM, Claremont.
FIGURE 16. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) of Harding County, South Dakota, USA. Photographs and line drawings of (1) NSM PV24644, a right epiplastron, in ventral and dorsal views; (2) NSM PV24645, a right hyoplastron, in ventral and dorsal views; (3) NSM PV24646, a right hypoplastron, in ventral and dorsal views; (4) NSM PV24647, a right xiphiplastron, in ventral and dorsal views; (5) NSM PV24648, a left xiphiplastron, in dorsal and ventral views; (6) NSM PV24649, a right hypoplastron, in ventral and dorsal views; (7) NSM PV24650, a cranium, in dorsal and ventral views.
FIGURE 17. Axestemys infernalis sp. nov. from the Late Cretaceous (Maastrichtian) of Niobrara County, Wyoming, USA. Photographs and line drawings of (1) the posterior portion of the carapace in dorsal view and of the (2) the left hyo/hypoplastron, (3) the right xiphiplastron, and (4) the left xiphiplastron in ventral and dorsal views of FHSM VP200. Two neurals and two partial costals mounted with this specimen were digitally removed, as they do not appear to belong to the same individual. Abbreviations: co = costal; ne = neural.
FIGURE 18. Enlarged photographs and line drawings of Axestemys infernalis sp. nov. crania from the Late Cretaceous (Maastrichtian) Hell Creek Formation. DMNH 130951 in (1) dorsal, (2) ventral, and (3) lateral views; NSM PV24650 in (4) dorsal and (5) ventral views; DMNH 98814 in (6) dorsal and (7) ventral views. Abbreviations: bo = basioccipital; bs = basisphenoid; fr = frontal; ju = jugal; mx = maxilla; op = opisthotic; pa = parietal; pal = palatine; pf = prefrontal; po = postorbital; pr = prootic; pt = pterygoid; qj = quadratojugal; qu = quadrate; so = supraoccipital; sq = squamosal; vo = vomer.
FIGURE 19. Enlarged photographs and line drawings of an Axestemys infernalis sp. nov. mandible from the Late Cretaceous (Maastrichtian) Hell Creek Formation. DMNH 130952 in (1) dorsal, (2) left lateral, and (3) left medial views. Abbreviations: ang = angular; art = articular; cor = coronoid; den = dentary; fM = fossa Meckelii; fna = foramen nervi auriculotemporalis; pra = prearticular; sM = sulcus Meckelii; sur = surangular.
