Search the Community
Showing results for tags 'Placodermi'.
Found 3 results
Red Hill is a site I first went to 10 years ago with my son, Ian who was 10 at the time. It is a very deep road cut into the uppermost part of the Catskill Formation representing a late Fammenian river system that was draining the Acadian mountains to the east and emptying into the inland sea in western PA and OH. It is one of a handful of sites in the world where Devonian tetrapods have been found. The site has fossil layers in both channel margin (red layers) and flood plain (gray-green layers) facies. While it is an active research site and groups go there under the understanding that anything of scientific importance will be donated to the museum, there is a lot there that is redundant in the collections and we've been able to retain. In 2014, Ian found an exceptionally preserved moderately large osteolepiform, Hyneria (Tristichopteridae). Some of the material went into the re-description of Hyneria, much we have been allowed to take home. Since then the project has expanded to a search for more tetrapod material using the jackhammer and generator the museum purchased. This may require multiple posts. I'll start with the jaws recovered over 2014/15 seasons. This lens containing most of the head from apparently a single individual. Here Ian is working with Ted Daeschler and Doug Rowe (site manager) of the Academy Of Natural Sciences in Philadelphia. Here are some images of the jaw material after removal and after prep by Fred Mullison of the ANSP. Lower left jaw after removal. This is the lower right jaw (right) and the vomer and very impressive fang. Amazingly, in 2016, we went back. I was leading a trip for DVPS. Ian found this amazing but poorly prepped jaw (I did this one). Here are a pair of cleithrums, about 29 cm long. The attachments for the scapulocoracoid are clearly visible between 17 and 21 cm. Here is part of the parietal shield. More to follow.
Mahnmut posted a topic in General Fossil DiscussionHello dear people, I wonder where to find information and reference-images on the postcranial skeleton of dunkleosteus or related species. You find images of their iconically armoured skulls everywhere, but not a hint of the "fishbones". Is there so little fossil record? I hope someone can give me a hint. Thanks, J
a book review of: "Swimming in Stone: The Amazing Gogo Fossils of the Kimberley" by John Long. Fremantle Arts Centre Press. 2006. 320 pages. Suggested Retail Price: $21.95 USD. Anyone who has collected fish fossils of any kind knows that they tend to be found in the form of isolated teeth, jaw sections, vertebrae, or the few other more durable bones. Even when you collect at one of those rare deposits where complete skeletons are common, the specimens are flattened, crushed by the rock layers that formed on top of them. In paleontology, a flattened skeleton is a good specimen but since many of the deposits are not that old, geologically speaking, scientists are dealing essentially with modern fish orders and families that date back to the Cretaceous at the earliest. Whole other classes existed long before that - back to the time when fishes were biting their way to the top of the food chain. "Swimming in Stone: The Amazing Gogo Fossils of the Kimberley" is the story of a 375 million-year -old marine deposit in an arid and remote part of Western Australia. The Gogo Formation is a nodule-bearing limestone layer, the nodules of which contain an incomparable treasure: fishes preserved as three-dimensional specimens: uncrushed skulls and skeletons with evidence of muscle and cartilage attachments. Thorough studies of the Late Devonian Gogo fishes have allowed scientists a much better understanding of early representatives of osteichthyans (bony fishes) and placoderms. a long-extinct class that appeared in the Early Silurian and ruled the Devonian seas. The author, John Long, has worked as a vertebrate paleontologist and museum curator/representative, specializing in Devonian fishes for nearly thirty years. He has been a prominent researcher of the Gogo with much of his professional life involved in the collection, preparation, and study of its fishes as well as in the conservation and promotion of the deposit. An extended introduction imagines the living Gogo environment, a tropical reef. It moves forward in time as geologic processes deeply buried it and later slowly exposed the nodule-bearing bed now representing the reef. The reader learns a little local human history as well. The book is then divided into 3 parts subdivided into 21 chapters. The first part is a historical account of Gogo studies from fieldwork to labwork; the second is a guide to the various fishes known from there. In the third part Long looks at how the deposit has been reinterpreted over the years, comparing it to other same-age fisheries. Long writes about how some anatomical features in humans can trace their origins to Devonian fishes and can be seen in Gogo forms (skull structure, basic limb structure, enamel-coated teeth, etc.). Long writes in an easy-going style pausing to define technical terms and explain complex concepts. The reader gets to know him as an average guy as well as a scientist. Captions in the margin provide further background on topics related to same-page text. This book is reasonably well-illustrated. The reader encounters 4-8 pages of solid text in only a few chapters. The figures are printed in black-and-white but Chapter 8 holds several full-color plates. The figures range from drawings (reconstructions, charts) to photos (locations, fossil photos, portraits) and it is a good mix. The paleogeographic map at the beginning of Chapter 19 confronts us with an unfamiliar jumble of continents still en route to uniting as Pangaea. I would recommend "Swimming in Stone" to anyone interested in Paleozoic fishes especially placoderms and their contemporaries. Collectors who have dug up pieces of placoderm armor in other parts of the world would appreciate a mainstream paleo title they can relate to. It is a good light read about unusual fossils within a story set in an exotic locale - almost foreign even to many Australians. It would also appeal to anyone who enjoyed the recent premiere of "Your Inner Fish" on American public television (based on Neil Shubin's 2008 book). Jess