FIGURE 1. Map of Yosobé and La Lobera, near Tlaxiaco, Oaxaca, Mexico.
FIGURE 2. Map of the Tlaxiaco Basin and distribution of the vertebrate fossil localities and areas reported before the present manuscript. 1, Cerro de la Virgen; 2, Petlalcingo area; 3, Wieland´s area; 4, Amoltepec area; 5, Papalutla; 6; La Lobera; 7, Yosobé (6 and 7 are new localities reported in the present paper).
FIGURE 3. Geologic map of Tlaxiaco showing the position and shape Yosobé and La Lobera localities (modified from SGM 2000a, 2000b, 2009).
FIGURE 4. Geologic map and lithostratigraphical column of Yosobé. M, Marl stratum; L1-L8, limestone strata; the intermediate strata (L1-L2, L2-L3,... L7-L8) are the bituminous shales layers that carry the vertebrate assemblage of Yosobé.
FIGURE 5. Yosobé locality. 1, general view of this locality showing the limestone layers (arrows) and fossil-bearing shale strata (between the arrows), and part of the village of Tlaxiaco in background. 2, bituminous and fossiliferous shale layers at Yosobé with some nodules in situ (arrows).
FIGURE 6. Planohybodus sp. from Yosobé; 1, isolated and fragmented tooth, specimen IGM 9316. 2-5, fragment of a dorsal spine in anterior (2), lateral (3), posterior (4), and cross-section (5) views, specimen IGM 9317. Arrow indicates the anterior edge of the predorsal spine.
FIGURE 7. Gyrodus sp., specimen IGM 9318 from Yosobé. 1, general view. 2, close up of possible vomerine teeth. Abbreviations: dsoc, dermosupraoccipital; fr, frontal; hm, hyomandibular; op, opercle; pa, parietal; pop, preopercle; s, scale; sc, sclerotic.
FIGURE 8. Jurassic remains of Ginglymondi fishes from localities near Tlaxiaco. 1-4, Scheenstia sp., specimen IGM 9320 from Tithonian strata of La Lobera, including a group of disarticulated scales (1), isolated scale (2), and a possible fragment of a vomer with teeth (in ventral view and lateral view, 3 and 4, respectively). 5, isolated scale of an undetermined Lepisosteiform described here as Morphotype 1, specimen IGM 9321 from Kimmeridgian strata of Yosobé. 6-7, scales of both sides of the body of an undetermined Lepisosteiform described here as Morphotype 2, specimen IGM 9322 from Kimmeridgian strata of Yosobé. Abbreviations: adp, anterior dorsal process; avp, anterior ventral process; dp, dorsal process; arrows indicate the anterior edge of the scales.
FIGURE 9. Trunk remains of a Pleuropholidae fish, specimen IGM 9323 from Yosobé. Abbreviations: fsc, body-flak scales; rsc, rhomboidal scales.
FIGURE 10. Vertebrates of marine reptiles from Yosobé. 1-3, Specimen IGM 9324, undetermined thalattosuchian crocodyliform in anterior (1), dorsal (2), and lateral (3) views. 4-6, Specimen IGM 9325, undetermined ophtalmosaurid ichthyosaur in anterior (4), dorsal (5), and ventral (6) views. In both specimens the arrows show the anterior direction. Abbreviations: dp, diapophysial process; fna, facet for the neural arch; ias, intervertebral articular surfaces; ncf, neural canal floor; ncs, neurocentral suture; nf, nutritive foramen; ns, neural spine; pz, posterior zygapophysis.
