戈壁锯齿象(Serridentinus gobiensis Osborn & Granger, 1932)和同心中新乳齿象(Miomastodon tongxinensis Chen, 1978)再研究：关于粗壮型轭齿象(Zygolophodon)的讨论

王世骐, 张晓晓, 李春晓

Reappraisal of Serridentinus gobiensis Osborn & Granger and Miomastodon tongxinensis Chen: the validity of Miomastodon

WANG Shi-Qi, ZHANG Xiao-Xiao, LI Chun-Xiao

Fig. 1 Terminology and measurements of mastodont molars A. right M3 of Sinomastodon praeintermedius, denoting the terminology of tooth crown; B. molar crown measurements; C. molar height measurements; D, E. the development of pretrite accessory elements in a typical zygodont molar, Zygolophodon turicensis, only pretrite crescentoids present (D), and in a typical bunodont molar, Gomphotherium connexum, only pretrite central conule present in the lophid 2 (E);F, G. the cross-sections of lower tusks, showing the “erected oval cross-sectioned mandibular tusk” in Miomastodon merriami, in which Ddv > Dml (F), and the “laid oval cross-sectioned” in Gomphotherium productum, in which Ddv < Dml (G). Note that the discrimination of the pretrite accessory elements in the panels A, D, E: green color, pretrite crescentoids; blue color, pretrite central conules. Panels F and G were modified from Frick (1933). Abbreviations: L. length; L1+2. length of the first two loph(id)s; H. height;Hpo. height of the posttrite side; Hpr. height of the pretrite side; W. width;W1, 2, …, 5. width of the 1st, 2nd, …, 5th loph(id); Wpo2. width of the second posttrite half loph(id)