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Showing results for tags 'lochkovian'.
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Adam's Early / Lower Devonian
Tidgy's Dad posted a topic in Member CollectionsThe Devonian period is known as "The Age of Fish", but could also be known as "The Age of Brachiopods." In the Early / Lower Devonian, brachiopods reached the height of their diversity towards its end in the Emsian. We see the ancestral groups occurring, lingulids, craniids, orthids, protorthids, pentamerids, rhynchonellids and strophomenids, as well as the later successful groups we have seen before such as atrypids, athyrids and orthotetids, plus the rise of spiriferids, spiriferinids and productids and the beginning of the terebratulids. By the end of the Devonian , several of these g
Tidgy's Dad posted a topic in Fossil IDHello, friends. This specimen comes from the Catskills, New York and is from the Helderberg Group, Lochkovian or Lowermost Early Devonian in age. It could be from Becraft Mountain. It's not a rhynchonellid, it's too flat and there's no notable fold or sulcus. It develops second second order costellae half way toward the anterior margin : I have a couple of not very convincing thoughts but would be very interested in your opinions. Thank You.
Details of two Rhinopteraspid Fish's Ventral Preoral Regions
Biotalker posted a topic in General Fossil DiscussionI thought I would share this recent fossil purchase. I was fortunate to obtain this fossil from the lower Devonian in the southwestern region (Podolia) of Ukraine. Two ventral snout regions of type of heterostracan (jawless) fish called rhinopteraspid are exposed. The bone detail is simply remarkable. There is “tiling” of the underside of the long (rhino) snouts with dentine and/or aspidine (acellular enamel-like substance) in parallel lines arrays with a more uniform bone matrix underneath. The pre-oral-plate is angled in toward the mouth and displays many external textures of bone that presu
oilshale posted a fossil in PlantsProbably Gosslingia breconensis Heard 1927. Taxonomy from Fossilworks.org. Edwards 1970, p. 226: “In his preliminary report in 1925, Heard had called the plant Psilophyton, but he renamed it Gosslingia when he presented an account of its anatomy and morphology in 1927.” Emended diagnosis for the genus (Edwards 1970, p. 237): "Plant rootless and leafless. Gregarious erect axes cylindrical, dichotomously and pseudomonopodially branched, arising from dichotomously branched rhizomes with rhizoids. Stems circinately coiled in apical regions: surfaces of some axes with protuberances;