| 释义 |
symmetrodont, n. and a.|sɪˈmɛtrəʊdɒnt|
[f. mod.L. order name Symmetrodonta (G. G. Simpson 1925, in Amer. Jrnl. Sci. CCX. 560), f. symmetry + Gr. ὀδούς, ὀδοντ- tooth, in allusion to the form of the teeth (see quot. 19792).]
A. n. A fossil mammal of the order Symmetrodonta, known from remains found in North America and Europe.
B. adj. Of or pertaining to an animal of this kind or the order including it.
1933A. S. Romer Vertebr. Paleont. xii. 260 The symmetrodonts seem to have been somewhat off the main evolutionary line. 1950Nature 21 Oct. 696/2 The specimen can easily be described as a lower symmetrodont cheek tooth. 1977A. Hallam Planet Earth 223 Triconodont and symmetrodont mammals died out during the Cretaceous. 1979R. C. Fox in Fairbridge & Jablonski Encycl. Paleont. 429/2 Symmetrodonts were small shrew⁓sized mammals, probably having insectivorous food habits. Ibid., Symmetrodont molars are highly characteristic; both upper and lower crowns formed simple occlusal triangles... The lower molar triangles are reversed in respect to the uppers and occlusion was alternate in the sense that each molar occluded within the embrasure between two successive molars on the opposite jaw. |