Wednesday, July 29, 2009

Oldest Known Aboreal Herbivore Found...IN THE PERMIAN!

(Reconstruction of the basal anomodont Suminia getmanovi. (a) Flesh and (b) skeletal reconstruction.)
The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems

Jorg Frobisch(1)*
Robert R. Reisz(2)

1 Department of Geology, The Field Museum, Chicago, IL 60605, USA
2 Department of Biology, University of Toronto at Mississauga, Mississauga, ON L5L 1C6, Canada

Vertebrates have repeatedly filled and partitioned the terrestrial ecosystem, and have been able to occupy new, previously unexplored habitats throughout their history on land. The arboreal ecospace is particularly important in vertebrate evolution because it provides new food resources and protection from large ground-dwelling predators. We investigated the skeletal anatomy of the Late Permian (approx. 260 Ma) herbivorous synapsid Suminia getmanovi and performed a morphometric analysis of the phalangeal proportions of a great variety of extant and extinct terrestrial and arboreal tetrapods to discern locomotor function and habitat preference in fossil taxa, with special reference to Suminia. The postcranial anatomy of Suminia provides the earliest skeletal evidence for prehensile abilities and arboreality in vertebrates, as indicated by its elongate limbs, intrinsic phalangeal proportions, a divergent first digit and potentially prehensile tail. The morphometric analysis further suggests a differentiation between grasping and clinging morphotypes among arboreal vertebrates, the former displaying elongated proximal phalanges and the latter showing an elongation of the penultimate phalanges. The fossil assemblage that includes Suminia demonstrates that arboreality and resource partitioning occurred shortly after the initial establishment of the modern type of terrestrial vertebrate ecosystems, with a large number of primary consumers and few top predators.

Keywords: Synapsida; Anomodontia; arboreality; terrestrial ecosystem; evolution


A fscking Permian squirrel! Or monkey! Well, not exactly, but, fscking wow with a blink tag!

Paper link above...and it's freely available. GO READ!

UPDATE: Possible prehensile tail AND *THUMBS*.


Zachary Miller said...

As just as an added bonus, he's CUTE, too!

Anonymous said...

Looks more like a chameleon than anything else, to me.

The Squamata have gone in for arboreality in a big way, especially in the tropics; hot-climate trees are generally crawling with lizards and snakes. So, what filled that niche before Squamata really got going? (The earliest squamate fossils are from the early Jurassic; the group is probably older than that, but it didn't start to radiate massively until the Cretaceous. So, what was scampering around in the trees in the Triassic?

Doug M.

Will Baird said...

Drepanosaurs, Doug, were the Triassic tree swingers.

Some bits of Suminia seem like they are chameleon like, except, well, this guy is related to dicynodonts and, therefore, a synapsid/therapsid. It also is a herbivore, which is rare so far for deep time tree climbers.