I know, I know, nobody gives two craps anymore, but I try.
Say hello to
Suminia getmanovi, who has already broken some important barriers in the 15 years since it was first described (Ivakhnenko 1994). Until just recently, the cute little synapsid was known only from a wonderfully-preserved skull, which demonstrated that Suminia was among the first tetrapods to develop a shearing bite (herbivorous). In the newest edition of Proceedings of the Royal Society B, (
http://rspb.royalsocietypublishing.org/content/early/2009/07/24/rspb.2009.0911), Frobisch & Reisz describe a slab containing some fifteen Suminia skeletons at various levels of completeness, and make a rather startling claim about them:
Suminia was arboreal!
Arboreality--that is, climbing around in trees--is fairly easy to spot in a skeleton. Grasping climbers (like squirrels, monkeys, and chameleons) have predictably convergent skeletal features that allow easy movement through the trees. Among these adaptations are elongate fingers and toes with small claws and (usually) opposability of one or more digit. An elongate torso also helps.
Suminia has both elongate hands and feet, and its 1st manual digit (thumb) is offset from the other four, implying opposability. The tail shows some features suggesting it was prehensile (like chameleons, drepanosaurs, and new world monkeys), but the skeletons will require further, more detailed study for that verdict.
The media, who never know what to do with non-mammalian synapsids, have been running some funny headlines, including "Early human relative predates dinosaurs!" (MSNBC) which they then changed to "Mammals' family tree predates dinosaurs," which misses the point entirely and still manages to be sort of wrong.
Y'see, kids, Mammalia is a monophyletic group of amniotes that form BUT ONE BRANCH of the Synapsida, an enormous group that also bore out critters like Lystrosaurus, Dimetrodon, Gorgonops, and Lycosuchus. Synapsida is the sister group of the Sauropsida, which includes every other group of living amniotes, including turtles, snakes, lizards, crocs, and dinosaurs. So saying Suminia is an early human relative is kind of like saying that turtles are early bird relatives. Yeah, they're on the same major branch (Sauropsida) but it's a meaningless statement at best, and a dishonest one at worst.
Anyway, Suminia is an arboreal synapsid from the PERMIAN, which is mind-blowing in itself.