Equus sp.
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publication ID |
https://doi.org/ 10.26879/1285 |
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persistent identifier |
https://treatment.plazi.org/id/542C8794-FFD8-FF81-BD06-FAA58073FABA |
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treatment provided by |
Felipe |
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scientific name |
Equus sp. |
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Referred material. Left mandible with three complete deciduous premolars dp2, dp3, and dp4 ( BUAPAL 780; Figure 3I–J View FIGURE 3 ), right p3 ( BUAPAL 771; Figure 3G View FIGURE 3 ), and left m2 ( BUAPAL 772; Figure 3H View FIGURE 3 ). Description. The left hemimandible has three deciduous premolars that are slightly worn. The length of the dp2 to dp4 is approximately 100 mm. The molariform p3 and m2 have an Al = 24.0 mm, Tw = 13.04 mm, Al = 22.4 mm, and Tw = 14.47 mm, respectively.
Comparison and remarks. The values of the dp2 to dp4 is within the variation of length of p2-p4 of adults E. mexicanus p2-p4 length = (86.99–109.95 mm), instead the other species of Pleistocene adult horses the maximum value of p2-p4 length is 92.6 mm (Priego-Vargas et al., 2017) ( Table 3). Jiménez-Hidalgo et al. (2019) describe a jaw of a juvenile E. mexicanus with deciduous premolars with a length of the dp2 to dp4 = 120 mm from Chiapas, Mexico. The juvenile specimen from Chiapas is larger than BUAPAL 780 and because the teeth of juvenile individuals do not present diagnostic
Anteroposterior length Transverse width Species Mean Min–Max N Mean Min-Max N
M2
BUAPAL 773 — 24.6
E. mexicanus 29.65 26.35–31.50
E. conversidens 22.75 20.50–25.80
H. francisci 19.55 18.10–20.50
M3
BUAPAL 774 — 24.33
E. mexicanus 31.35 27.5–36.33
E. conversidens 23.85 21.50–27.45 1 — 23.81 1
6 28.18 25.80–31.40 6
32 22.54 19.79–24.20 32
4 18.28 16.37–20.00 4
1 — 19.31 1
6 24.89 23.30–27.80 6
32 19.51 17.10–23.70 32
H. francisci 22.45 21.60–23.05 3 15.53 14.00–17.30 3
characters to separate between species of horses, we determine the fossil material to genus level.
The molariforms are smaller than E. mexicanus , and its measurements are within the ranges of E conversidens and E. cedralensis . The molariforms exhibit advanced deterioration on the occlusal surface, but the prefosette and postfosette are visible. In the right p3 the u-shaped linguaflex, possibly pointed metastyle, entoconid possibly square and almost absent equine fold. The left m2 presents a v-shaped linguaflex, apparently round entoconid and # aballing fold. Several qualitative occlusal characters do not fall into the description reported for small horses in the literature (Sánchez-Salinas et al., 2016; Priego-Vargas et al., 2017), therefore we determine the fossil material to genus level.
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