Table 1 —Measurements of molar teeth of Rhynchotherium and Cuvieronius , following Alberdi et al. (2002). In the source column, for each molar specimen either the collection number or the reference where the metric data were obtained is indicated. In the tooth column the letter beside the molar

Table 2 —Known localities of Rhynchotherium and Cuvieronius in Mexico. The column symbol (S) refers to its position in Figure 6 . (x) = Undetermined localities, not shown in map. Source column indicates the latest known reference; see text for other references

Figure 5 —Detail of the maxillary tusk of Cuvieronius Osborn, 1923 in lateral view (DP-5778), showing enamel band. Scale bar = 10 cm

Figure 2 —IGM 6084. Lower jaw of Cuvieronius tropicus . Scale ×1/3.

Table 1 —Measurements of lower jaws of Cuvieronius : IGM 6084 and 6083 are specimens from Puebla and IGM 4007 is the type specimens of C. oligobunis (Cope, 1884). Abbreviations used by Ficcarelli et al., (1993) and Figure 4

Figure 3 —IGM 6084. Occlusal view of the molars of the right ramus of Cuvieronius tropicus . Scale ×1/3

Figure 6 —Approximate location of the known records in Mexico of Rhynchotherium (letters) and Cuvieronius (numbers), including localities reported herein. See Table 2 for details

Figure 3. Variation in δ 13 C (A) and δ 18 O (B) during the middle and late Pleistocene for South American Cuvieronius and Stegomastodon . BBAA = Buenos Aires

Figure 7 —Bivariate diagram of length versus maximum width from measurements in Table 1; m2, M2, m3, and M3 for Rhynchotherium specimens; m3-C for Cuvieronius specimens

Figure 1. A, Geographical distribution and dispersal routes of different species of the family Gomphotheriidae in South America. Pointed arrow: possible dispersion route of the genus Cuvieronius . Solid arrow: possible dispersion route of species from genus Stegomastodon . B, Geographical

Figure 2. Bivariate plots of stable isotope values and dental microwear attributes for proboscidean samples from the Atlantic Coastal Plain. Circles (blue online), Cuvieronius hyodon ; triangles (brown online), Mammut americanum ; squares (green online), Mammuthus columbi . Mean values

). δ 13 C vmeq VPDB (‰) δ 18 O enamel VSMOW (‰) Age Taxon n Mean Median Min Max Range SD (1σ) SE p -value Mean Median Min Max Range SD (1σ) SE p -value Bl5 Cuvieronius hyodon 20 −20.9 −20.2 −27.6 −17.8 9.8 2.3 0.5 0 . 004 29.6 29.4 27.8 32.9 5.1 1.1

Table 3. Descriptive statistics for eight compared groups of South American gomphotheres. A, Cuvieronius , all specimens. B, C. hyodon from Ecuador. C, C. hyodon from Bolivia. D, Stegomastodon , all specimens. E, S. platensis , all specimens. F, S. platensis from late Pleistocene. G, S

factor (ɛ*) obtained using body-size estimates. Ch, Cuvieronius hyodon ; Ma, Mammut americanum ; Mc, Mammuthus columbi . C, UF 80004, left m3. Scale bar, 10 cm. Cross-hatching represents area where dental microwear texture analysis (DMTA) mold was sampled, with 3D surface model of wear facet (higher