Leedsichthys - Facts and Figures

Leedsichthys - Facts and Figures Name: Leedsichthys (Greek for Leeds fish); pronounced leeds-ICK-thissHabitat: Oceans worldwideHistorical Period: Middle-Late Jurassic (189-144 million years ago)Size and Weight: 30 to 70 feet long and five to 50 tonsDiet: PlanktonDistinguishing Characteristics: Large size; semi-cartilaginous skeleton; thousands of teeth About Leedsichthys The last (i.e., species) name of Leedsichthys is problematicus, which should give you some clue about the controversy occasioned by this gigantic prehistoric fish. The problem is that, although Leedsichthys is known from dozens of fossil remains from around the world, these specimens dont consistently add up to a convincing snapshot, leading to grossly divergent size estimates: more conservative paleontologists venture guesses of about 30 feet long and 5 to 10 tons, while others maintain that superannuated Leedsichthys adults could attain lengths of over 70 feet and weights of over 50 tons. Were on much firmer ground when it comes to Leedsichthys feeding habits. This Jurassic fish was equipped with a whopping 40,000 teeth, which it used not to prey on the larger fish and marine reptiles of its day, but to filter-feed plankton (much like a modern Blue Whale). By opening its mouth extra-wide, Leedsichthys could gulp in hundreds of gallons of water every second, more than enough to cover its outsized dietary needs. As with many prehistoric animals discovered in the 19th century, the fossils of Leedsichthys were an ongoing source of confusion (and competition). When the farmer Alfred Nicholson Leeds discovered the bones in a loam pit near Peterborough, England, in 1886, he forwarded them to a fellow fossil hunter, who misidentified them as the back plates of a stegosaur dinosaur. The next year, during a trip overseas, the eminent American paleontologist Othniel C. Marsh correctly diagnosed the remains as belonging to a giant prehistoric fish, at which point Leeds made a brief career of excavating additional fossils and selling them to natural history museums. One little-appreciated fact about Leedsichthys is that its the earliest identified filter-feeding marine animal, a category that also includes prehistoric whales, to attain giant sizes. Clearly, there was an explosion in plankton populations during the early Jurassic period, which fueled the evolution of fish like Leedsichthys, and just as clearly this giant filter-feeder went extinct when krill populations mysteriously plunged at the cusp of the ensuing Cretaceous period.

The History and Archaeology of Chauvet Cave

The History and Archaeology of Chauvet Cave Chauvet Cave (also known as  Chauvet-Pont dArc) is currently the oldest known rock art site in the world, apparently dating to the Aurignacian period in France, about 30,000-32,000 years ago. The cave is located in the Pont-dArc Valley of Ardà ¨che, France, at the entrance of the Ardà ¨che gorges between the Cevennes and Rhone valleys. It extends horizontally for nearly 500 meters (~1,650 feet) into the earth and consists of two main rooms separated by a narrow hallway. Paintings at Chauvet Cave Over 420 paintings have been documented in the cave, including numerous realistic animals (reindeer, horses, aurochs, rhinoceros, bison, lions, cave bears among others), human handprints, and abstract dot paintings. The paintings in the front hall are primarily red, created with the liberal applications of red ochre, while the ones in the back hall are mainly black designs, drawn with charcoal. The paintings at Chauvet are highly realistic, which is unusual for this period in Paleolithic rock art. In one famous panel (a little bit is shown above) an entire pride of lions is illustrated, and the feeling of movement and power of the animals is tangible even in photographs of the cave taken in poor light and at low resolution. Archaeological Investigation The preservation in the cave is remarkable. Archaeological material in Chauvet caves deposits include thousands of animal bones, including the bones of at least 190 cave bears (Ursus spelaeus). The remains of hearths, an ivory spearhead, and a human footprint have all been identified within the caves deposits. Chauvet Cave was discovered in 1994 by Jean-Marie Chauvet; the relatively recent discovery of this remarkably intact cave painting site has allowed researchers to closely control the excavations using modern methods. In addition, the researchers have worked to protect the site and its contents. Since 1996, the site has been under investigation by an international team led by Jean Clottes, combining geology, hydrology, paleontology, and conservation studies; and, since that time, it has been closed to the public, to preserve its fragile beauty. Dating Chauvet The dating of Chauvet cave is based on 46 AMS radiocarbon dates taken on tiny pieces of paint from the walls, conventional radiocarbon dates on human and animal bone, and Uranium/Thorium dates on speleotherms (stalagmites). The deep age of the paintings and their realism has led in some circles to a scholarly revision of the notion of paleolithic cave art styles: since radiocarbon dates are a more recent technology than the bulk of cave art studies, codified cave art styles are based on stylistic changes. Using this measure, Chauvets art is closer to Solutrean or Magdalenian in age, at least 10,000 years later than the dates suggest. Paul Pettitt has questioned the dates, arguing that the radiocarbon dates within the cave are earlier than the paintings themselves, which he believes are Gravettian in style and date to no earlier than about 27,000 years ago. Additional radiocarbon dating of the cave bear population continues to support the original date of the cave: the bone dates all fall between 37,000 and 29,000 years old. Further, samples from a nearby cave support the idea that cave bears may have been extinct in the region by 29,000 years ago. That would mean that the paintings, which include cave bears, must be at least 29,000 years old. One possible explanation for the stylistic sophistication of Chauvets paintings is that perhaps there was another entrance to the cave, that allowed later artists access to the cave walls. A study of the geomorphology of the cave vicinity published in 2012 (Sadier and colleagues 2012), argues that the cliff overhanging the cave collapsed repeatedly beginning 29,000 years ago, and sealed the only entrance at least 21,000 years ago. No other cave access point has ever been identified, and given the morphology of the cave, none is likely to be found. These findings do not resolve the Aurignacian/Gravettian debate, although even at 21,000 years of age, Chauvet cave remains the oldest known cave painting site. Werner Herzog and Chauvet Cave In late 2010, film director Werner Herzog presented a documentary film of Chauvet Cave, shot in three-dimensions, at the Toronto film festival. The film, Cave of the Forgotten Dreams, premiered in limited movie houses in the United States on April 29, 2011. Sources Abadà ­a OM, and Morales MRG. 2007.  Thinking about style in the post-stylistic era: reconstructing the stylistic context of Chauvet.  Oxford Journal of Archaeology  26(2):109-125. Bahn PG. 1995. New developments in Pleistocene art.  Evolutionary Anthropology  4(6):204-215. Bocherens H, Drucker DG, Billiou D,  Geneste  J-M, and van der Plicht J. 2006.  Bears and humans in Chauvet Cave (Vallon-Pont-dArc, Ardà ¨che, France): Insights from stable isotopes and radiocarbon dating of bone collagen.  Journal of Human Evolution  50(3):370-376. Bon C, Berthonaud V, Fosse P, Gà ©ly B, Maksud F, Vitalis R, Philippe M, van der Plicht J, and Elalouf J-M.  Low Regional Diversity Of Late Cave Bears Mitochondrial  Ã‚  Journal of Archaeological Science  In Press, Accepted Manuscript.Dna  At The Time Of Chauvet Aurignacian Paintings. Chauvet J-M, Deschamps EB, and Hillaire C. 1996. Chauvet Cave: The worlds oldest paintings, dating from around 31,000 BC.  Minerva  7(4):17-22. Clottes J, and Lewis-Williams D. 1996. Upper Palaeolithic cave art: French and South African collaboration.  Cambridge Archaeological Journal  6(1):137-163. Feruglio V. 2006  De la faune au bestiaire - La grotte Chauvet-Pont-dArc, aux origines de lart parià ©tal palà ©olithique.  Comptes Rendus Palevol  5(1-2):213-222. Genty D, Ghaleb B, Plagnes V, Causse C, Valladas H, Blamart D, Massault M, Geneste J-M, and Clottes J. 2004.  Datations U/Th (TIMS) et 14C (AMS) des stalagmites de la grotte Chauvet (Ardà ¨che, France) : intà ©rà ªt pour la chronologie des à ©và ©nements naturels et anthropiques de la grotte.  Comptes Rendus Palevol  3(8):629-642. Marshall M. 2011.  Bear DNA hints at age of Chauvet cave art.  The New Scientist  210(2809):10-10. Sadier  B, Delannoy JJ, Benedetti L, Bourlà ©s DL, Stà ©phane J,  Geneste  J-M, Lebatard A-E, and Arnold M. 2012. Further constraints on the Chauvet cave artwork elaboration. Proceedings of the National Academy of Sciences Early edition. Pettitt P. 2008.  Art and the Middle-to-Upper Paleolithic transition in Europe: Comments on the archaeological arguments for an early Upper Paleolithic antiquity of the Grotte Chauvet art.  Journal of Human Evolution  55(5):908-917. Sadier  B, Delannoy JJ, Benedetti L, Bourlà ©s DL, Stà ©phane J,  Geneste  J-M, Lebatard A-E, and Arnold M. 2012.  Further constraints on the Chauvet cave artwork elaboration.  Proceedings of the National Academy of Sciences  Early edition.