FIGURE 1. A: Map of Mexico with the state of Coahuila marked. B: Geological map of the Jimenez area (redrawn from Servicio Geológico de México, 2008). The Tepeyac locality is marked by an asterisk.
FIGURE 2. The Tepeyac section, the stable carbon isotope curve and events, ammonoid species occurrences and ranges, and biozonation by ammonoids. Dashed lines mark species occurrences elsewhere.
FIGURE 3. Plesiotexanites shiloensis Young, 1963 from the Tepeyac section. A-C: IGM 12795, bed TPY 14; D-F: CPC-2378, bed TPY 33; G: bed TPY 38, not collected. Scale: 50 mm.
FIGURE 4. Texanites lonsdalei Young, 1963 from the Tepeyac section. A: in bed TPY11; B: IGM 12796, bed TPY 21 C-D: IGM 12797, bed TPY 14; E-G: CPC-2377, bed TPY33. Scale: 50 mm.
FIGURE 5. Bevahites from the Tepeyac section. A-B, G-J: Bevahites bevahensis, A-B: CPC-2374; G-J: CPC-2547, both bed TPY26; C-F: Bevahites costatus coahuilaensis, C-D: CPC-2372, bed TPY27; E-F: CPC-2548, beds TPY40-46. Scale: 50 mm.
FIGURE 6. Menabites (Delawarella) tequesquitense (Young, 1963) from bed TPY33 of the Tepeyac section. A-B: CPC-2381. Scale: 50 mm.
FIGURE 7. Menabites (Delawarella) tequesquitense (Young, 1963) from the middle Tepeyac section. A: CPC-2381, TPY33, B-C: CPC-2383, TPY36. Scale: 50 mm.
FIGURE 8. Menabites (Delawarella) tequesquitense (Young, 1963) from bed TPY36 of the Tepeyac section. CPC-2383, left lateral view. Scale: 50 mm.
FIGURE 9. Menabites (Delawarella) tequesquitense (Young, 1963) from bed TPY36 of the Tepeyac section. CPC-2383, right lateral view. Scale: 50 mm.
FIGURE 10. Menabites (Delawarella) tequesquitense (Young, 1963) from the Tepeyac section. CPC-2422, bed of origin unknown. Scale: 50 mm.
FIGURE 11. Menabites (Delawarella) delawarensis (Morton, 1830) from bed TPY35 of the Tepeyac section. A-D: CPC-2382. Scale: 50 mm.
FIGURE 12. Menabites (Delawarella) delawarensis (Morton, 1830) from the middle Tepeyac section. A-C: CPC-2386, TPY40. D-G: CPC-2388, TPY50. Scale :50 mm.
FIGURE 13. Menabites (Delawarella) delawarensis (Morton, 1830) from bed TPY50. A-D: CPC-2388. Scale: 50 mm.
FIGURE 14. Menabites (Delawarella) danei (Young, 1963) from bed TPY77. A-B: CPC- 2421. Scale: 50 mm.
FIGURE 15. Menabites (Delawarella) n. sp. from the upper Tepeyac section. A-C: CPC- 2393, TPY73. D-F: CPC-2560, TPY74. Scale: 50 mm.
FIGURE 16. Menabites (Delawarella) vanuxemi (Morton, 1830) from the middle Tepeyac section. A-D: CPC-2379, TPY33. E: CPC-2390, TPY50. F: CPC-2391, TPY50. Scale: 50 mm.
FIGURE 17. Menabites (Delawarella) mariscalense (Young, 1963) from the Tepeyac section. A-D: CPC-2402, from bed TPY74, E-G: CPC- 2401 from bed TPY75, H-K: CPC-2380 from bed TPY33. Scale: 50 mm.
FIGURE 18. Compressed Menabites (Delawarella) from the Tepeyac section. A-B: Menabites (Delawarella) vandaliense (Young, 1963), CPC-2576 from bed TPY77. Menabites (Delawarella) uddeni (Young, 1963) C-D: CPC-2399, E-H: CPC-2400, both from bed TPY74; I-J: CPC-2416, K-N: CPC- 2415, both from bed TPY77. Scale: 50 mm.
FIGURE 19. Menabites (Bererella) walnutensis (Young, 1963) from beds TPY54 to TPY60. A-B: CPC-2392, TPY54-56. C-D: CPC-2581, TPY60. E-G: CPC- 2549, TPY69top. Scale: 50 mm.
FIGURE 20. Menabites (Bererella) walnutensis (Young, 1963) from bed TPY74. A-B: CPC-2404. C-F: CPC- 2406. Scale: 50 mm.
FIGURE 21. Menabites (Bererella) walnutensis (Young, 1963) from bed TPY77. A-C: CPC-2394 from bed TPY73; D-F: CPC-2419 from bed TPY77. CPC- 2582 from bed TPY77. Scale: 50 mm.
FIGURE 22. Menabites (Bererella) walnutensis (Young, 1963) from bed TPY77. A-C: CPC-2580. Scale: 50 mm.
FIGURE 23. Morphometry of Menabites (Bererella) walnutensis (Young, 1963). Full Diamonds: WB/WH for TPY, empty diamonds: WB/WH from Kennedy et al. (1997b), full circles: U/D for TPY, empty circles: U/D from Kennedy et al. (1997b).
FIGURE 24. Pseudoschloenbachia (P.) mexicana (Renz, 1936) from the lower and middle Tepeyac section. A-C: CPC-2339, TPY13. D-F: CPC-2334, TPY48-50. Scale: 50 mm.
FIGURE 25. Pseudoschloenbachia (P.) mexicana (Renz, 1936) from bed TPY48 of the Tepeyac section. A-D: CPC-2337. Scale: 50 mm.
FIGURE 26. Pseudoschloenbachia (P.) mexicana (Renz, 1936) from the Jiménez region. A-C: CPC-2351. Scale: 50 mm.
FIGURE 27. Pachydiscus (Pachydiscus) duelmensis (Schlüter, 1972) from bed TPY40. A-B: CPC-2561. Scale: 50 mm.
FIGURE 28. Pachydiscus (Pachydiscus) duelmensis (Schlüter, 1972) from bed TPY50. A-B: CPC- 2195. Scale: 50 mm.
FIGURE 29. Pachydiscus (Pachydiscus) duelmensis (Schlüter, 1972) from bed TPY50. A-B: CPC-2545. Scale: 50 mm.
FIGURE 30. Pachydiscus (Pachydiscus) duelmensis (Schlüter, 1972) from the Tepeyac section. A: CPC-2545, imprint of inner whorl. B-E: CPC-2197, bed TPY76. Scale: 50 mm.
FIGURE 31. Morphometry of lower Campanian Menuites and Pachydiscus. A: WB/WH and U/D against D for Pachydiscus (P.) duelmensis from Tepeyac (red) and Germany (green), the holotype of Pachydiscus jimenezi Renz, 1936 (turquoise) and Pachydiscus paulsoni of Young (1963, grey) and Cobban and Kennedy (1992b, blue). B: WB/WH and U/D against D for Menuites stephensoni from Tepeyac (red) and western Coahuila (Ifrim et al., 2013, black). Morphometric data of Young (1963) are implausible and thus not shown.
FIGURE 32. Pachydiscids from the Tepeyac section. A-B: Pachydiscus (Pachydiscus) duelmensis (Schlüter, 1972), CPC-2193 from bed TPY40; C-F: Menuites stephensoni Young, 1963, CPC-2194 from bed TPY50. Scale: 50 mm.
FIGURE 33. Menuites stephensoni Young, 1963 from bed TPY62. A-B: CPC-2562. Scale: 50 mm.
FIGURE 34. Menuites stephensoni sp. from the Tepeyac section. A-D: CPC-2196 from bed TPY69-89. Scale: 50 mm.
FIGURE 35. Glyptoxoceras texanum Kennedy, Landman and Cobban, 2001 from the Tepeyac section. A-D: CPC-2349, bed TPY48-50; E-F: CPC-2610, bed TPY73. Scale: 50 mm.
FIGURE 36. Amapondella amapondense (van Hoepen, 1921) from bed TPY50 of the Tepeyac section. A-C: CPC-2345, D-E: CPC-2346. Scale: 50 mm.
FIGURE 37. Amapondella amapondense from bed TPY 50 of the Tepeyac section. A-E: CPC-2347. Scale: 50 mm.
FIGURE 38. Baculites from the Tepeyac section. A-B, G-H: Baculites taylorensis, A-B: CPC-2198, bed TPY64; G-H: CPC-2199 before extraction from bed TPY77; C-F, I-L: Baculites haresi, C-F: CPC-2607, bed TPY52; I-L: CPC2606, bed TPY77. Scale: 50 mm.
FIGURE 39. Scaphites (S.) hippocrepis III from bed TPY73 of the Tepeyac section. A–D, I–L: CPC–2599; E–H, M–P: CPC–1600, both from bed TPY72. Scale: 50 mm.
FIGURE 40. Biozonations used for the upper Santonian to lower Campanian stages in the northwestern Gulf Coast Plain.
FIGURE 41. The early Campanian World with localities presenting ammonites with affinities to northeastern Coahuila (e.g., Tepeyac). Endemic species are summarized in the asterisk. Species with a wider occurrence are marked in other regions, but not in the northwestern Gulf region. Map courtesy of Scotese (2021).
