Paleontologists have described the earliest known animal adapted for life in the treetops, according to a paper in the Proceedings of the Royal Society B, released online today. Jörg Fröbisch, of the Field Museum, and Robert Reisz, from the University of Toronto, found several adaptations for arboreality when they examined fossil skeletons of Suminia getmanovi , a small (20 inches/50 cm) herbivore from the Late Permian of Russia.

The most striking features of the skeleton of Suminia are the relatively large hands and feet. Most of their length is taken up by long, slender fingers and toes tipped with strongly curved, laterally (side-to-side) compressed claws, which are similar in proportion and shape to some modern tree-clinging animals, including dermopterans, megabats, and lizards. The first digits on the hands and feet diverge from the remaining four digits as well, and may have been used as opposable ‘thumbs’ as the animal clung to the branches.

Skeleton of Suminia getmanovi, Paleontological Institute (Moscow) specimen number 2212/116 (spec. 1) Photo by Diane Scott.

More subtle features also point toward arboreal habits. The tail of Suminia is relatively long, and the vertebrae show strong processes halfway down its length. These processes could have supported muscles that allowed Suminia to use its tail for balance or, possibly, as a prehensile grasping organ.

Suminia, at 260,000,000 years old, is the first known vertebrate with this degree of arboreal specialization. Fröbisch and Reisz note that the Late Permian Period, and the Kotel’nich locality where Suminia was found, provides some of the earliest evidence for “modern terrestrial ecosystems with large numbers of plant-eaters supporting few top predators.” While large megaherbivores fed on the greenery below, Suminia found a new way to exploit the foliage in the treetops, taking the first known step into a niche that vertebrates would return to several times over the next 260 million years.

Life restoration of Suminia getmanovi by Christina Stoppa.

Lawless teeth

In part because of some very poorly-written articles and headlines, and in part because talking about vertebrate relationships is just plain enjoyable, it seems like a good place to put in a little bit of context regarding exactly what Suminia is related to.

Suminia is a synapsid, a group of vertebrate animals that would eventually (some 50-100 million years after Suminia) give rise to the ancestors of today’s mammals. Although some synapsids have been called “mammal-like reptiles,” (because they certainly laid eggs and might have looked something like lizards) there are no true reptiles in the synapsid group. All true reptiles—turtles, lizards, snakes, crocodiles—even dinosaurs and birds—belong to a completely separate group.

Among the synapsids, Suminia is considered a therapsid, a phrase commonly used to indicate a grade of synapsid development in between the earlier pelycosaur-grade (think Dimetrodon) and the later mammal-grade. (Although, since mammals evolved from therapsids, we’re technically therapsids too, and since therapsids evolved from pelycosaurs, we can all claim that title as well.)

Among the therapsids, Suminia is an early member of the anomodont (“lawless tooth”) lineage. Sometime during the Early/Middle Permian period, the anomodont line split off from the line of therapsids that would, by way of a whole bestiary of gorgonopsians and therocephalians and countless cynodonts, eventually lead to mammals. The closest relatives we (and all other mammals) share with Suminia would have lived before the Late Permian, around 275,000,000 years ago (give or take several million years) .

The anomodonts have no living descendants, but their roster includes the great radiation of dicynodonts that survived the end-Permian extinction, became some of the largest terrestrial herbivores of the Triassic, and might possibly have survived into the Cretaceous if the identification of an Australian fossil is correct.

Placerias hesternus, a Late Triassic anomodont from Arizona. (Illustration by me, for the day job)

Contrary to what you might have read regarding this discovery, dinosaurs did not evolve from synapsids, and while Suminia is a human relative, this potential predator of Suminia is a much closer relation.

• Reference: Fröbisch, J. and Reisz, R. R. 2009. The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems. Proc. Royal Soc. B Published online before print July 29, 2009, doi: 10.1098/rspb.2009.0911.
• Web Coverage:
  • Press Release [ZIP file]
  • BBC News: Fossil is the earliest tree-dweller
  • Laelaps: Suminia: Life in the trees 260 million years ago
  • The Dragon’s Tales: Oldest Known Arboreal Herbivore Found…IN THE PERMIAN!

Some images and info for this post came from this press release.

• Several prime pelycosaur posts from recent field work in the Permian beds of Seymour, including Dimetrodon-as-chondrichthivore and new material that may be from the narrow-snouted finback Secodontosaurus .
• And a step-by-step look at how Julius T. Csotonyi recreated the world of Leonardo, the fantastically well-preserved Brachylophosaurus, for the museum’s Dinosaur Mummy CSI: Cretaceous Science Investigation exhibit. Csotonyi’s digital paintings are about the best I’ve seen, and this post gives valuable insight into his process.

A few weeks old, but worth noting: World’s oldest flying insect fossil. A beautiful resting trace from a Carboniferous insect that landed with its limbs sprawled out like a mayfly; found in Massachusetts by a geology student at Tufts University.

Moving back in time, Chris Nedin kicks off his new Ediacaran blog with a compelling Cambrian tale of how flexible trilobites avoided unlucky breaks in The Spandrels of San Marco and the Anomalocaris Paradigm.

Speaking of the Cambrian, scientists are furthering their insight into the exceptional preservation of the famous Burgess Shale fossils, according to this article.

And  The Life of Madygen provides a brief introduction to the Triassic titanopterans, an extinct group of insects, related to grasshoppers and crickets, but with wingspans reaching half-a-meter across!

A photo and a closeup of the astounding Chengjiang “Chained Arthropods”
Photos by Derek Siveter from the University of Oxford Media Release.

The researchers who reported on these fossils in this week’s issue of Science suspect that these ancient “conga lines” might reflect some sort of migratory behavior.

• Reference: Hou, X.-G., Siveter, D. J., Aldridge, R. J., and Siveter, D. J. 2008. Collective Behavior in an Early Cambrian Arthropod. Science: 322: 5899, p. 224. doi: 10.1126/science.1162794
• Web Coverage:
  • University of Oxford press release
  • Science News: New Arthropod Species Really Stuck Together
  • National Geographic: “Daisy Chains” of Fossil Creatures Found in China
  • Catalogue of Organisms: Chain Chain Chain

• New Amphibian: Gerobatrachus hottoni
• Name means:Hotton’s Elder Frog
• Relations: Amphibamid temnospondyl and stem-batrachian (an early offshoot on the lineage leading to frogs and salamanders)
• Location: Texas, U.S.A.
• Age: Early Permian, ~290,000,000 years ago
• Size: Less than 12cm (5 inches) long
• Info: The three groups of living amphibians (frogs, salamanders, and caecilians) most certainly had their roots in the great amphibian radiations of the Late Paleozoic Era, but the fossil record has provided few clues that help pinpoint their precise ancestry. Gerobatrachus was a small temnospondyl, part of a very successful and numerous group of amphibians in the latter part of the Paleozoic. The remains of Gerobatrachus exhibit a unique mosaic of features in its teeth, ears, limbs, and vertebrae that suggest it may have been close to the origins of both modern frogs and salamanders. Although many researchers have proposed a close relationship between all three groups of living amphibians, a phylogenetic analysis that included Gerobatrachus found that caecilians had their origins in a completely different group of Paleozoic amphibians, the lepospondyls.
• Reference: Anderson, J. S., Reisz, R. R., Scott, D., Fröbisch, N. B., and Sumida, S. S. 2008. A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature 453, 515–518 (22 May 2008) | doi:10.1038/nature06865. The article is available for download from the Center for North American Herpetology PDF Library.
• Web coverage:
  • Press Release
  • LiveScience on MSNBC
  • The Dragon’s Tales 1 & 2
  • Palaeoblog
  • El PaleoFreak

First up, Will at The Dragon’s Tales has had a couple of great articles on two of the more charismatic groups from the latter days of the Paleozoic: the carnivorous, sabre-toothed gorgonopsians and the herbivorous, tusk-beaked dicynodonts. Plus, he notes that there are some fantastic restorations of Permian vertebrates showing up on Wikipedia.

Speaking of dicynodonts, The Lord Geekington, mentions the ubiquitous Permo-Triassic straddler Lystrosaurus in his review of aquatic habits in stem-group synapsids. At the other end (that is, the beginning) of the Permian, he also discusses the potentially piscivorous pelycosaur Ophiacodon.

Finally, I recently came across the Houston Museum of Natural Science’s Prehistoric CSI blog, whose archives are chock full of fossil finds from Seymour, Texas—a treasure trove of Early Permian vertebrates—with videos and photos, and field sketches by Dr. Robert Bakker.

According to Wikipedia, the WIPP site was chosen, in part, because the salt deposits have remained relatively stable since they precipitated from a receding Permian sea, over 250,000,000 years ago. Presumably, the same stability helped preserve the earliest direct evidence of biological life—nearly four times the age of the previous record holder: traces of protein from 68 million year-old T. rex fossils.

Cellulose microfibers, from the UNC News press release.

Cellulose microfibers were the most abundant biological materials found, although the article tantalizingly mentions that some evidence of ancient DNA was “observed.”

Now a quarter-billion year-old bit of biomass is pretty darn nifty, and since the research is published in April’s issue of Astrobiology it leads to some interesting ideas about the possibility of finding durable bio-molecules preserved in salt deposits on other worlds. But I think there’s far greater potential for speculation here. I mean, we’ve got Paleozoic biology in proximity to low-level radiation. Forget the atom-bomb triggered monster ants of THEM!—imagine a pickled monuran, revivified and grotesquely enlarged by the careless placement of a used radiation suit, leaping out across the desert as it attempts to satisfy 250 million years worth of salt-cured hunger…

First up, a fossil claw of the eurypterid (sea scorpion) Jaekelopterus rhenaniae could have come from the largest arthropod that ever lived. The claw, described in Biology Letters, measures 46 cm in length, and presumably was part of a Jaekelopterus individual 2.5 meters (8.2 feet) long. The story has been well-covered by National Geographic News, The Loom, and Palaeoblog.

This week’s issue of the journal Science has a few brief articles on research presented at last month’s Society of Vertebrate Paleontology Annual Meeting. One provocatively titled story, “Did Horny Young Dinosaurs Cause Illusion of Separate Species?”, reports on the work of John Horner, Mark Goodwin, and Holly Woodward, which suggests that the spiky-headed pachycephalosaurs Dracorex hogwartsia and Stygimoloch spinifer might, in fact, be juvenile forms of the knobby domehead Pachycephalosaurus wyomingensis. Update (11/24): Manabu Sakamoto has a summary of Horner et al.’s presentation up at his blog, Raptor’s Nest.

Finally, researchers at the Royal Tyrrell Museum have announced the discovery of a new ceratopsian dinosaur: Eotriceratops xerinsularis (ee-oh-try-SAIR-ah-tops zeer-in-soo-LAIR-iss), the “Dawn Three-horned face from Dry Island (Buffalo Jump Provincial Park)”. This 68,000,000 year old dinosaur is a couple of million years older than Triceratops, and it may be the ancestor of that well-known genus. Eotriceratops and Triceratops shared several features such as large brow horns and a solid frill, but Eotriceratops also possessed some more primitive characteristics than its younger relative, according to this story in the Edmonton Journal. The three-meter-long skull of Eotriceratops (reconstructed in this photo) would seem to put it in the running for the largest head of any terrestrial animal, alongside other ceratopsian contenders such as Torosaurus and Pentaceratops.

Photo credit: Spencer G. Lucas,
New Mexico Museum of Natural History and Science

Spencer G. Lucas (New Mexico Museum of Natural History and Science), David L. Fillmore and Edward L. Simpson (both from Kutztown University in northeastern Pennsylvania) presented this unique fossil at the 2007 GSA Annual Meeting. Spencer asked me to draw up a reconstruction showing the temnospondyls whose imprints were preserved in the fossil, which I took particular pride in, since I, too, happen to be a tetrapod from eastern Pennsylvania. My take on the temnospondyl trio is shown below:

My take on the temnospondyl trio. The impressions in the fossil slab are raised, so when you look at it you are
actually seeing the animals’ imprints from underneath; in this top-down view their positions are flipped horizontally.

This drawing was included in the press release but, due to a miscommunication, it was not initially credited. Oddly enough, I was back in northeast PA visiting family when the release went out, so I didn’t realize it until I returned to New Mexico yesterday. I’m happy to say that the oversight has since been corrected on the GSA page.

But beyond my personal stake in the story, the fossil really is quite spectacular. The imprints seem to show your standard temnospondyl four-fingered hand, and what looks like a crease of skin down the midline of their bellies, with no apparent sign of scales. As Lucas et al. note in their abstract, the fact that the three were preserved together indicates some sort of gregarious activity, and the tastefully phrased “head-to-tail overlap” shown in two of the impressions is reminiscent of the courtship behaviors of some modern amphibians.

While looking it over, and with any number of gift-shopping seasons fast approaching, I thought it might be handy to use the HMNH Paleo-Pop Shop page to help promote other purveyors of paleontology-themed items around the web, at least until I scrape together the funds to come up with some more custom Hairy Museum merchandise. I’ve listed a few worthy shops, but I’m sure there are many more out there, so pass along any recommendations in the comments or directly to me at paleopopshop [at] hmnh.org.

At this point, my only rules are: 1. There should be a way to order (or at least browse) store merchandise online, 2. There should be a significant portion of paleontology or natural history themed merchandise, and 3. I’d just as soon bypass any ethical issues surrounding the sale of fossils, so no shops selling actual fossil material will be included.

Other than that, feel free to plug yourself, your friends, or anything else you’d like to see!