My daughter is six today.
How did THAT happen so fast?!
Almost 600 million years ago, before the rampant evolution of diverse life forms known as the Cambrian explosion, a community of seaweeds and worm-like animals lived in a quiet deep-water niche under the sea near what is now Lantian, a small village in Anhui Province of South China. Then they simply died, leaving some 3,000 nearly pristine fossils preserved between beds of black shale deposited in oxygen-free waters.Scientists from the Chinese Academy of Sciences, Virginia Tech in the U.S., and Northwest University in Xi'an, China report the discovery of the fossils and the mystery in the Feb. 17 issue of Nature. *In addition to perhaps ancient versions of algae and worms, the Lantian biota – named for its location – included macrofossils with complex and puzzling structures. In all, scientists identified about 15 different species at the site.The fossils suggest that morphological diversification of macroscopic eukaryotes – the earliest versions of organisms with complex cell structures -- may have occurred only tens of millions of years after the snowball earth event that ended 635 million years ago, just before the Ediacaran Period. And their presence in the highly organic-rich black shale suggests that, despite the overall oxygen-free conditions, brief oxygenation of the oceans did come and go."So there are two questions," said Shuhai Xiao, professor of geobiology in the College of Science at Virginia Tech. "Why did this community evolve when and where it did? It is clearly different in terms of the number of species compared to biotas preserved in older rocks. There are more species here and they are more complex and larger than what evolved before. These rocks were formed shortly after the largest ice age ever, when much of the global ocean was frozen. By 635 million years ago, the snowball earth event ended and oceans were clear of ice. Perhaps that prepared the ground for the evolution of complex eukaryotes."The team was examining the black shale rocks because, although they were laid down in waters that were not good for oxygen-dependent organisms, "they are known to be able to preserve fossils very well," said Shuhai. "In most cases, dead organisms were washed in and preserved in black shales. In this case, we discovered fossils that were preserved in pristine condition where they had lived – some seaweeds still rooted."The conclusion that the environment would have been poisonous is derived from geochemical data, "but the bedding surfaces where these fossils were found represent moments of geological time during which free oxygen was available and conditions were favorable. They are very brief moments to a geologist," said Xiao. "but long enough for the oxygen-demanding organisms to colonize the Lantian basin and capture the rare opportunities."The research team suggests in the article in Nature that the Lantian basin was largely without oxygen but was punctuated by brief oxic episodes that were opportunistically populated by complex new life forms, which were subsequently killed and preserved when the oxygen disappeared. "Such brief oxic intervals demand high-resolution sampling for geochemical analysis to capture the dynamic and complex nature of oxygen history in the Ediacaran Period," said lead author Xunlai Yuan, professor of palaeontology with the Chinese Academy of Sciences.
The postcranial anatomy of Suminia getmanovi (Synapsida: Anomodontia), the earliest known arboreal tetrapodJÖRG FRÖBISCH, ROBERT R. REISZArticle first published online: 21 JAN 2011DOI: 10.1111/j.1096-3642.2010.00685.xAbstract:The basal anomodont Suminia getmanovi Ivakhnenko, 1994 from the late Palaeozoic of Russia is highly specialized in its masticatory apparatus, and has been suggested to represent the earliest arboreal tetrapod in the fossil record. Its postcranial anatomy is described in detail for the first time, revealing a large number of autapomorphies for this small herbivore. These include a reduced number of presacral and therein dorsal vertebrae, an elongate neck, a long and possibly prehensile tail, a procoracoid with a notch at its ventromedial margin rather than a foramen, an iliac blade with a robust ridge at its anteromedial edge, a pubis with a puboischiadic fenestra and separate pubic foramen, and elongate limbs. Additional autapomorphic characters are displayed in the autopodium, which comprises about 40% of the entire limb length. These features include an enlarged, phalangiform distal carpal 1 and tarsal 1, a short and robust first metacarpal, a crescent-shaped distal tarsal 4, and elongate penultimate phalangeal elements. The phylogenetic relationships of basal anomodonts are revisited using an expanded data set, with the addition of key taxa and several postcranial characters. Unlike dicynodonts, Suminia retained the plesiomorphic phalangeal formula for amniotes of 2-3-4-5-3 (manus) and 2-3-4-5-4 (pes). This pattern is achieved by the retention of disc-like phalangeal elements between the proximal and penultimate phalanges in digits III, IV (manus and pes), and V (pes only). In light of the new material, Suminia can be recognized as the most complete basal anomodont, offering new insights into the early evolution of the group.
As a former owner of a PT Cruiser, I can safely say the iPad probably did more damage to the car than the other way around.
Surprising new research shows that, contrary to conventional belief, remains of chitin-protein complex—structural materials containing protein and polysaccharide—are present in abundance in fossils of arthropods from the Paleozoic era. Previously the oldest molecular signature of chitin-protein complex was discovered in 25 million year old Cenozoic fossils and remnants of structural protein have also been discovered in 80 million-year-old Mesozoic fossils. Carnegie's George Cody and an international team of scientists discovered relicts of protein-chitin complex in fossils of arthropods from the Paleozoic era. Their findings, published online by Geology, could have major implications for our understanding of the organic fossil record.Among other common features, arthropods have exoskeletons, or cuticles. The outer portions of these cuticles are made up of a composite of chitin fibers, which are embedded in a matrix of protein. It is well known that chitin and structural protein are easily degraded by microorganisms and it has long been believed that chitin and structural proteins would not be present in fossils of moderate age, let alone in fossils dating back to the early Paleozoic.Cody and his team studied fossil remains of a 310-million-year-old scorpion cuticle from northern Illinois and a 417-million-year-old eurypterid—an extinct scorpion-like arthropod, possibly related to horseshoe crabs—from Ontario, Canada. Using sophisticated analytical instrument at the Advanced Light Source facility, the research team measured the absorption spectra of low-energy X-rays by carbon, nitrogen, and oxygen in the fossils. These measurements were taken at a resolution on the order of 25 nanometers. The researchers showed that the majority of carbon, nitrogen and oxygen found in these fossils from the Paleozoic era were derived from a protein-chitin complex. Not surprisingly, the protein-chitin material was somewhat degraded, either by chemical processes or partial bacterial degradation.