Chengjiang Chain Gang
Some impressive fossils from the Chengjiang Lagerstätte in China hit the news this week—a heretofore undescribed type of Cambrian arthropod that was preserved shell-to-tail in long chains, kind of like half-billion year-old invertebrate snap-lock beads.
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.
—Matt Celeskey.
File under: Cambrian, Invertebrates.
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Gerobatrachus hottoni
- Gerobatrachus hottoni
Painting by Michael Skrepnick,
from the press release at EurekAlert.
- 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:
—Matt Celeskey.
File under: Permian, Recent Discoveries, Tetrapods.
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Permian Meanderings
In which I play “catch-up” for a few sites overlooked in my absence (note the partially-updated blogroll to the left). Today I’ll point out some excellent posts from the past few months dealing with different aspects of the Permian:
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.
—Matt Celeskey.
File under: Permian, Reptiles, Synapsids, Tetrapods.
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It came from WIPP
From Will Baird I learned of this story of 253 million year-old biological material recovered from subterranean salt deposits near Carlsbad. The material was found by analyzing the contents of microscopic bubbles in salt and halide crystals from the site of the Waste Isolation Pilot Plant (WIPP), a repository for low-level radioactive waste deep beneath the southeast New Mexico desert.
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…
—Matt Celeskey.
File under: Permian, Recent Discoveries.
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Paleo news wrap-up
Several interesting tidbits of paleo news have been reported this week:
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.
—Matt Celeskey.
File under: Cretaceous, Devonian, Dinosaurs, Invertebrates, Recent Discoveries.
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