New materials of Exallerix pustulatus (Erinaceidae, Eulipotyphla) from Nei Mongol and other Brachyericinae of China Vertebrata Palasiatica    2025, 63 (4): 335-349.   DOI: 10.19615/j.cnki.2096-9899.250910

Fig. 2 Exallerix pustulatus from IM 2204, Nei Mongol inlateral (1) and occlusal (2) views
A. left mandibular fragment with p4-m1 (IVPP V34183.1); B. left mandibular fragment with m1-2 (V34183.2); C. left mandibular fragment with m1-2 (V34183.3); D. left mandibular fragment with trigonid of m1 and m2 (V34183.4); E. right mandibular fragment with i1, p4-m1 (V34183.5); F. right mandibular fragment with m1 (V34183.6)

Extracts from the Article

(Fig. 2)

The p4: the p4 possesses a single prominent main cusp, the protoconid, centrally located over the anterior root. The protoconid is roughly triangular-pyramidal in shape, with a slightly swollen labial surface. A vestigial paraconid is visible on the p4 of V34183.5 (Fig. 2E), similar to that seen in Synexallerix junggarensis (Bi, 1999). A well-developed heel is present on the posterolingual side. The crown slopes sharply downward, forming an extremely deep labial face that is almost entirely covered by embossed sculpturing. Only the upper portion of the labial surface of the protoconid, along with the lingual and distal surfaces, remains unornamented. The arrangement of the enamel ornamentation appears irregular.

The m1: as noted by Ziegler et al. (2007), the trigonid of the m1 is relatively short anteroposteriorly and wide transversely. The ratio of trigonid length to width ranges from 1.05 to 1.32 (Fig. 2). This ratio is significantly higher than that of Metechinus from North America and comparable to or lower than that of other short-faced hedgehogs (Lopatin and Zazhigin, 2003). The trigonid is fully open lingually. The ratio of talonid length to trigonid length ranges from 0.48 to 0.60 (Fig. 4), which is slightly higher than in other species of Exallerix (Lopatin and Zazhigin, 2003). The talonid is approximately equal in width to the trigonid. The metaconid sits close to the protoconid, and the two cusps are separated by a shallow depression. The entocristid is low, with a height approximately equal to that of the cristid obliqua and postcristid. The talonid lacks a hypoconulid, though some individuals have a metastylid (e.g., V 34183.6, Fig. 2F). The labial surface of the crown, particularly the paralophid and cristid obliqua, is unornamented in the upper third to quarter. The lingual surface of the crown is mostly unornamented except near the lingual opening of the trigonid. Enamel knobs or tubercles form at least three elongated longitudinal rows on the labial face of the crown and several shorter rows on the labial aspect of the roots. These rows are wavy and run approximately parallel to each other. Additional enamel tubercles are scattered between or along the margins of these rows.

Other Images/Table from this Article

• Fig. 1  Geological historical distribution of short-faced hedgehogs in the world For data and source references see Supplementary data 1
• Table 1  Measurement of Exallerix pustulatus from IM 2204, Nei Mongol (mm)
• Fig. 3  CT graphs of mandibular fragment of Exallerix pustulatus (IVPP V34183.2) A. transverse plane, through anterior root of the m1, anterior view; B. sagittal plane, lateral view, the white dashed line shows the alveolus of the i1
• Fig. 4  Comparison measurements of the m1 of Exallerix pustulatus with other short-faced hedgehogs For data and source references see Supplementary data 2
• Fig. 5  Statistics and comparison measurements of m1 of Exallerix pustulatus with other short-faced hedgehogs n: number of samples. Data and source references see Supplementary data 2
• Fig. 6  Statistics and comparison measurements of the m1 and m2 of Exallerix pustulatus with other short-faced hedgehogs n: number of samples. For data and source references see Supplementary data 2