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| Tamisiocaris borealis | |
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| Tweet Topic Started: Mar 27 2014, 04:19 AM (3,135 Views) | |
| Scalesofanubis | Mar 27 2014, 04:19 AM Post #1 |
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Omnivore
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Tamisiocaris borealis![]() Photo credit: Rob Nicholls, palaeocreations. Artist's reconstruction of T. borealis. Temporal range: Cambrian Stage 3 Scientific classification Kingdom: Animalia Class: † Dinocaridida Order: † Radiodonta (?) Genus: † Tamisiocaris Species: † Tamisiocaris borealis Tamisiocaris (see latin tamisium, sieve) is an anomalocaridid taxon initially only known from non-segmented great appendages from Sirius Passet. Further specimens revealed that the appendages near their mouths were adapted to filter feed in a manner analogous to modern baleen whales. http://www.nature.com/nature/journal/v507/n7493/full/nature13010.html http://arstechnica.com/science/2014/03/cambrian-hunter-switched-to-a-plankton-diet/ Edited by Taipan, Mar 30 2014, 02:07 PM.
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| Scalesofanubis | Mar 27 2014, 04:21 AM Post #2 |
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Omnivore
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Scientific Method / Science & Exploration Cambrian hunter switched to a plankton diet Like whale sharks, relatives of Anomalocaris evolved to filter feed. by Scott K. Johnson - Mar 26 2014, 1:00pm EST http://arstechnica.com/science/2014/03/cambrian-hunter-switched-to-a-plankton-diet/ The fossilized organisms of the Cambrian period some 500 million years ago are both alien and familiar. A few of them look a lot like the creatures around us today. But even some that don’t look at all familiar hold down ecosystem roles we can easily recognize—photosynthesizers, grazers, predators. The alien inhabitants of the ecosystem are well-represented by Anomalocaris and its kin. Looking like something out of a sci-fi movie, these arthropod-like animals were probably the kings and queens of the Cambrian seas—the top of the food chain. They grew up to a meter or two in length and swam around in search of prey to seize with the two appendages in front of their round, disc-like mouth. At least some of them did. New fossils suggest that one anomalocarid species ended up exchanging its role as a top predator for a more sedate lifestyle. While many sharks and whales live at the top of the modern marine food chain, some have evolved to harvest their meals much closer to the bottom instead. Baleen whales traded vicious teeth for a filter used to strain krill from the water. Similarly, whale sharks and basking sharks filter small morsels rather than chase after large prey. A new fossil find seems to show that some anomalocarids made the same career change. The fossil organism, named Tamisiocaris borealis, was first discovered a few years ago in northern Greenland by paleontologists Allison Daley and John Peel. New specimens analyzed by a team led by the University of Bristol’s Jakob Vinther have revealed that this organism was very different from other anomalocarids in an interesting way. The front appendages (which, together with one piece of the head, are the only parts of the organism found so far) don’t sport sturdy spikes well-suited to grasping large prey. Instead, a series of long, thin spikes each host many tiny spikes, like the structure of a feather. Together, this array of combs makes a fine net, with gaps of only one-half millimeter or so. Like a whale’s baleen, that suggests a very different style of feeding—filtering small plankton rather than spearing larger critters. And there were plankton around to be eating. Fossilized remains of both Cambrian photosynthetic phytoplankton and the zooplankton that eat them have been found. If this is correct, it implies some interesting things about the Cambrian world. First, the fossil comes from the early part of the Cambrian period, yet a pretty complex ecosystem must already have evolved in the ocean. It had been thought that such filter feeders, and a diverse set of plankton for them to snack on, didn’t appear until late in Cambrian time. Filter feeders also rely on dense concentrations of their prey— whales wouldn’t survive catching the odd krill here and there. That means that productivity in the Cambrian ocean must have been high, at least in some locations. The researchers also think that Tamisiocaris borealis also has something to say about the old debate over evolution’s predictability. It was this debate that prompted Stephen Jay Gould to write, “Wind back the tape of life to the early days of the [Cambrian]; let it play again from an identical starting point, and the chance becomes vanishingly small that anything like human intelligence would grace the replay.” More generally, this represents a view of evolution as largely free-form, with today’s life on Earth being just one realization of a nearly endless set of possibilities. On the other hand, it could be that environmental conditions and biological realities constrain those possibilities to a small subset (of which human-like intelligence may or may not be a high-probability member). The researchers point out that if sharks, whales, and anomalocarids all converged on similar adaptations and lifestyles within similarly structured ecosystems, the constraints on evolutionary possibilities seem pretty, well, constraining. It’s not just the similarities of those filter-feeding organisms, but the similarity of their ancestries—evolving from free-swimming apex predators. “This suggests that evolution is canalized not only in terms of outcomes,” they write, “but in terms of trajectories. The result is that independent evolutionary experiments by animals as different as anomalocarids, fish, and whales have converged on broadly similar outcomes.” Edited by Scalesofanubis, Mar 27 2014, 04:22 AM.
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| Scalesofanubis | Mar 27 2014, 04:41 AM Post #3 |
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Omnivore
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The Big Friendly Giants of the Cambrian Ocean March 24, 2014 | by Justine Alford Read more at http://www.iflscience.com/plants-and-animals/big-friendly-giants-cambrian-ocean#YeKM5JkzwDjctuqi.99 ![]() Photo credit: Rob Nicholls, palaeocreations. Artist's reconstruction of T. borealis. This is Tamisiocaris borealis, a newly described fossilized creature from Greenland that lived around 520 million years ago. Like certain types of modern whale, it possessed large appendages that were used to filter plankton and other small organisms from the ocean. These animals belonged to a group called anomalocarids. Anomalocarids were traditionally known as giant apex predators who used similar appendages as those possessed by Tamisiocaris to capture large prey. Intriguingly, Tamisiocaris borealis seems to have actually evolved its filter-feeding equipment from these prey-catching appendages during the Cambrian explosion, and is therefore an ancestor of modern-day suspension feeders. Why some of these animals underwent this dramatic transition in feeding is unclear, but it has happened several other times in history. The findings have demonstrated not only the diversity of different anomalocaridid species, but have also shed light on some of the ocean ecosystems that existed during this period. Lead author of the study published today in Nature, Dr Jakob Vinther, said in a press release "The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem. Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy- and therefore lots of food." A 3D computer animation of the animal was generated by Dr Martin Stein of the University of Copenhagen, in the hope of gaining insight into how these specialized appendages were utilized to feed. "Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth," said Dr. Stein. "This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence." The expeditions carried out in this area have revealed a gold mine of fossils just waiting to be characterized by scientists. Who knows what other exciting discoveries may be in the pipeline. Read more at http://www.iflscience.com/plants-and-animals/big-friendly-giants-cambrian-ocean#AIApE1O6iPZQghlk.99 |
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| Taipan | Mar 27 2014, 01:22 PM Post #4 |
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A suspension-feeding anomalocarid from the Early Cambrian Jakob Vinther, Martin Stein, Nicholas R. Longrich & David A. T. Harper Nature 507, 496–499 (27 March 2014) doi:10.1038/nature13010 Received 28 November 2013 Accepted 09 January 2014 Published online 26 March 2014 Abstract Large, actively swimming suspension feeders evolved several times in Earth’s history, arising independently from groups as diverse as sharks, rays and stem teleost fishes1, and in mysticete whales2. However, animals occupying this niche have not been identified from the early Palaeozoic era. Anomalocarids, a group of stem arthropods that were the largest nektonic animals of the Cambrian and Ordovician periods, are generally thought to have been apex predators3, 4, 5. Here we describe new material from Tamisiocaris borealis6, an anomalocarid from the Early Cambrian (Series 2) Sirius Passet Fauna of North Greenland, and propose that its frontal appendage is specialized for suspension feeding. The appendage bears long, slender and equally spaced ventral spines furnished with dense rows of long and fine auxiliary spines. This suggests that T. borealis was a microphagous suspension feeder, using its appendages for sweep-net capture of food items down to 0.5 mm, within the size range of mesozooplankton such as copepods. Our observations demonstrate that large, nektonic suspension feeders first evolved during the Cambrian explosion, as part of an adaptive radiation of anomalocarids. The presence of nektonic suspension feeders in the Early Cambrian, together with evidence for a diverse pelagic community containing phytoplankton7, 8 and mesozooplankton7, 9, 10, indicate the existence of a complex pelagic ecosystem11 supported by high primary productivity and nutrient flux12, 13. Cambrian pelagic ecosystems seem to have been more modern than previously believed. http://www.nature.com/nature/journal/v507/n7493/full/nature13010.html |
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| hawkkeye | Mar 27 2014, 09:10 PM Post #5 |
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Autotrophic Organism
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pls, what animals is that hollow fish-things on the picture with tamisiocaris? with some bioluminescence pattern on their sides. |
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| Taipan | Mar 27 2014, 09:40 PM Post #6 |
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Not sure - artists imagination? |
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