They weren't part of the perissodactyl group  itself; they're what's called a sister group.

它们本身不属于奇蹄类。他们就是所谓的姐妹团。

This was the environment that gave rise to the very first perissodactyls, hoofed mammals with an odd number of toes.

这是产生第一批奇蹄类动物的环境，奇蹄类动物是有奇数个脚趾的有蹄类哺乳动物。

From the anatomy of its feet, they could tell that it was a perissodactyl, or an " odd-toed ungulate, " that stood on three toes.

从它的脚的解剖结构来看，他们可以看出它是用三个脚趾站立的奇蹄类动物，或“奇蹄类动物”。

They were also most closely related to a group  called perissodactyls or odd-toed ungulates - like horses and rhinos - and not the group  that includes elephants and manatees.

它们也与称为奇蹄类或奇趾有蹄类动物（如马和犀牛）关系最密切，而不是包括大象和海牛在内的群体。

One of the first perissodactyls we know of was Hyracotherium, a small ungulate whose fossils were first discovered in England and named, for some reason, for its supposed resemblance to the rock hyrax.

我们所知道的最早的奇蹄类动物之一是始祖马，这是一种小型有蹄类动物， 其化石最早是在英格兰发现的，并出于某种原因因其与岩蹄兔的相似性而得名。