placentals

与placentals相关的网络例句 [注：此内容来源于网络，仅供参考]

Modern mammals divide into three overarching groups: the placentals, the marsupials and the monotremes (the egg-laying platypus and echidnas).

现代哺乳动物可被划分为三种主要的群体：胎盘哺乳动物(大多数物种都属于这一类，包括人类)、有袋动物与单孔目动物。

The monotremes split off about 166m years ago and the marsupials parted company with the placentals 148myears ago. That, however, was not news; the fossils tell a similar story.

在一亿六千六百万前单孔目动物就出现了物种分化且有袋动物脱离群体，而胎盘哺乳动物在一亿四千八十万年前出现类似情况。

Nothing much then happened for 50m years when, all of a sudden, the placentals (or, at least, those with surviving descendants) split into four so-called superorders.

之后的五千万年内没有任何新奇的事发生，就在这时，胎盘哺乳动物(或者说是那些有后代存活的哺乳动物)突然之间分化为四种所谓的生物总目。

A new spalacotheriid mammal preserved with a complete postcranium and a partial skull has been discovered from the Yixian Formation1, 2, 3 of Liaoning, China. Spalacotheroid symmetrodonts4, 5, 6, 7, 8, 9, 10, 11 are relatives to modern therians (combined group of marsupials and placentals) and are characterized by many skeletal apomorphies of therians.

中国的义县化石产地在过去十年时间里已经出产了一些最为重要的哺乳动物化石，比如说一系列长羽毛的恐龙化石，并且还在继续出产对关于早期哺乳动物演化的传统观点形成挑战的化石。