This makes it a contemporary to some early eutherian species that have been found in the same area.
12.
There are, however, striking differences as well as a number anatomical features that separate them from Eutherians.
13.
Although it is an XY system, the platypus'sex chromosomes share no homologues with eutherian sex chromosomes.
14.
:: Humans and cats almost certainly didn't develop nipples independently; they are both Eutherian mammals.
15.
Dugongs and elephants share a monophyletic group with hyraxes and the aardvark, one of the earliest offshoots of eutherians.
16.
All extant eutherians lack epipubic bones, which are present in all other living mammals ( marsupials and monotremes ).
17.
The oldest known eutherian species is " Juramaia sinensis ", dated at from the Jurassic in China.
18.
Let's imagine metatherians and prototherians become completely extinct in a few years, and eutherians are the only surviving mammals.
19.
Paleontologists generally regard the monotremes as the most primitive mammals and the eutherians as the most advanced, and they classify fossils accordingly.
20.
Marsupials and eutherian mammals typically have an even number of nipples arranged bilaterally, from as few as two to as many as 19.
