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5 December 2013 11:26 am ,
Vol. 342 ,
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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ScienceShot: Fossils of Enigmatic Sea Creature Surface
17 January 2013 9:00 am
New fossil finds reveal that an enigmatic seafloor dweller first described more than a decade ago was armored and much larger than its modern-day kin. Cotyledion tylodes had a goblet-shaped body that surrounded a U-shaped gut (dark feature in fossil at left; arrows denote flow of food), and the animal spent its life anchored to the seafloor or to hard objects that had settled there, such as the molted exoskeletons of trilobites (artist's representation at right). C. tylodes was first described in 1999 based on a couple of fragmentary fossils unearthed from 520-million-year-old rocks in southern China. Previously, some scientists have proposed that the tentacled creatures were related to cnidarians, a group that contains jellyfish. But analyses of the new fossils—hundreds of well-preserved specimens extracted from the same ancient rocks—reveal that the animals belong to a group called entoprocts, aquatic creatures that attach to surfaces and filter their food from passing currents, the researchers report online today in Scientific Reports. The oldest undisputed fossils of entoprocts are less than one-third the age of C. tylodes, so the new fossils push back the origin of the entoproct lineage all the way back to the so-called Cambrian explosion, an interval when life diversified very quickly to produce most of the groups seen today or their ancestors. C. tylodes, which measured between 8 and 56 millimeters tall, dwarfed its modern kin, which typically range between 0.1 and 7 millimeters. Also unlike modern-day entoprocts, C. tylodes was covered with distinctive, scalelike features called sclerites—a hint, the scientists say, that such armor may have been more common among ancestral entoprocts than has been previously recognized.
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