Instead they belonged to another, now extinct group called the " multituberculates."

相反，它们属于另一个现已灭绝的群体，称为“多瘤齿兽类”。

And so the fact we're finding these multituberculate mammals-a totally unrelated and ancient group of mammals-exhibiting social behavior means this was probably not uncommon among these early Mesozoic mammals.

因此，我们发现这些多瘤齿兽类动物——一种完全无亲缘关系的古老的哺乳动物群体——表现出社会行为的事实意味着，这在这些早期中生代哺乳动物中可能并不罕见。