FIGURE 1. Location map of Late Oligocene mammal localities and sections from the Kızılırmak Formation (Çankırı-Çorum Basin, north central Anatolia, Turkey). 1, geotectonic map of Central Anatolia showing the basins including the Çankırı-Çorum Basin, and the main structural features of the area; 2, Geological map of the studied area with the four fossil localities of the Kızılırmak Formation discussed in the text.

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FIGURE 2. The four sampled sections showing the stratigraphic position of fossil localities in the Kızılırmak Formation (modified from Karadenizli et al., 2004).

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FIGURE 3. Dental remains of Iberomeryx parvus and Iberomeryx sp. from the Kızılırmak Formation (early late Oligocene, Central Anatolia). Iberomeryx parvus : 1, Right maxilla with D2-M1 in occlusal view, GK2-4; 2, Left M2 in occlusal view, GK3-31; 3, Left M1 in occlusal view, KZ-7; 4-5, Left M2 in occlusal (4) and labial (5) views, TP641-12; 6-7, Right lower jaw with d3-d4 and the trigonid of m1 in occlusal (6, with line drawing below) and lingual (7) views, GK2-11; 8, Right P4 in occlusal view, GK3-5; 9-10, Right P2 in occlusal (9) and labial (10) views, GK3-4; 11, Left m1 in occlusal view, TP641-4; 12-13, Right m1 in occlusal (12) and labial (13) views, GK3-3; 14-15, Left lower jaw with the talonid of m1 and the trigonid of m2 in occlusal (14) and labial (15) views, TP641-1; 16-17, Left lower jaw with m3 in occlusal (16) and lingual (17) views, TP641-2; 18, Left i1 in lingual view, GK3-7; 19, Left i2 or i3 in lingual view GK3-6; 20, Right p3 in occlusal view, GK3-11; 21, Right p4 in occlusal view, GK3-36. Iberomeryx sp.: 22, Talonid of a left p4 in occlusal view, GK3-35. The scale bar 3 mm goes exclusively with the views 20 to 22.

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FIGURE 4. Postcranial remains of Iberomeryx parvus and Iberomeryx sp. from the Kızılırmak Formation (early late Oligocene, Central Anatolia). Iberomeryx parvus : 1, Right cubonavicular in anterior view, TP641-16; 2-3, Right astragalus in anterior (2) and posterior (3) views, GK3-39; 4, Right cubonavicular in anterior view, GK2-5; 5-6, Right astragalus in anterior (5) and posterior (6) views, GK3-37; 7, Left calcaneum in medial view, GK3-24. 8 , Right calcaneum in medial view, KZ-11; 9-11, Left distal humerus in anterior-cranial (9), lateral (10), and medial (11) views, GK3-22; 12-13, Proximal part of coalescent metatarsals III and IV in anterior (12), and medial (13) views, GK3-54; 14-16, phalanx proximalis in anterior (14), lateral (15), and proximal views, GK3-13; Iberomeryx sp. 17, Left cubonavicular in anterior view, KZ-2; 18-21, Right astragalus in anterior (18), posterior (19), lateral (20), medial (21) views, TP641-24. Anatomical abbreviations: acf, astragalo-calcaneal facet; ca, capitulum; daf, distal astragalar facet; fbf, fibular facet; imf, internal malleous facet; me, medial epicondyle; of, olecranon fossa; smt2, contact surface of the Mt2; stf, sustentacular facet.

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FIGURE 5. Dremotherium guthi : 1-3, Left m1 in occlusal (1), labial (2), and lingual (3) views, BA-1; 4, M2? In occlusal view, BA-6; Cf. Palaeohypsodontus sp.: 5-6, Right M2? in occlusal (5) and lingual (6) views, TP641-10; Lophiomerycidae indet.: 7, Right calcaneum in medial view, GK2-7; 8, Right p1 in labial view, TP641-9; 9, Right cubonavicular in anterior view, GK2-3. Large Pecora indet.: 10-11, Right astragalus in anterior (10) and posterior (11) views, KZ-9. Anatomical abbreviations: cf, calcaneal facet; fbf, fibular facet; stf, sustentacular facet. The scale bar 10 mm goes exclusively with the views 7 to 11.

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FIGURE 6. Stratigraphic ranges of Late Eocene to Oligocene ruminant species in Eurasia (adapted from Métais and Vislobokova, 2007); the Land Mammal Ages are based on Tong et al. (1995), and Woodburne (2006). The colored area designates the duration of the Late Oligocene Warming according to the chart of Zachos et al. (2001).

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FIGURE 7. Oligocene chronostratigraphic chart indicating the preliminary ages of the different fossil localities based on the unpublished magnetostratigraphic study (Sevket Sen, personal commun., 2016), and the Paleoclimatic context during the Oligocene. Oi1 and Oi2 designate main cooling and glaciation events (Adapted from Berggren et al. 1995, and Zachos et al., 2001 for the paleoclimatic chart)

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