{"product_id":"colonial-rugose-coral-head","title":"Colonial Rugose Coral Head","description":"\u003cp\u003eRugose corals are an extinct group of coral that lived on the ocean floor or within reefs, feeding off of tiny microplankton.\u003c\/p\u003e\n\u003cp\u003eRugose corals can form solitarily or as a colonial mass.\u003c\/p\u003e\n\u003cp\u003eThe skeletal wall of the coral is made of calcite and called the \u003cem\u003etheca\u003c\/em\u003e, which can be covered by the outermost skeletal sheath, the \u003cem\u003eepitheca\u003c\/em\u003e. Growth lines along the \u003cem\u003eepitheca\u003c\/em\u003e can appear wrinkly, hence they are called Rugose Corals -- \"\u003cem\u003eruga\u003c\/em\u003e\" being Latin for \"wrinkled.\" \u003c\/p\u003e\n\u003cp\u003eThe circular, bike-spoke parts are \u003cem\u003esepta\u003c\/em\u003e, and the lines radiating out from the center of the \u003cem\u003esepta\u003c\/em\u003e (\u003cem\u003ecolumella\u003c\/em\u003e) are \u003cem\u003ecosta\u003c\/em\u003e. \u003cem\u003eCosta\u003c\/em\u003e are not always visible in specimens due to preservation quality. \u003c\/p\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003eThe most well-known rugose coral is the Michigan Petoskey Stone (part of the Hexagonaria genus) which were rounded and tumbled by glaciers. \u003c\/p\u003e\n\u003cp\u003eFun fact: Corals grow a little bit every day and produce growth rings. Scientists studied daily fossil rugose coral growth lines, finding on average 400 lines for Middle Devonian corals (meaning around 400 days in a year 380 million years ago) and less than 390 rings for Pennsylvanian corals (around 390 days in a year 300 million years ago). This discovery suggests that over time, Earth's rate of rotation continues to slowly decrease. \u003c\/p\u003e\n\u003cp\u003eThis particular specimen has wonderfully detailed preservation of the septa and costa. The fossil is preserved with a reddish hue. \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eType: Colonial Rugose Coral Head\u003cbr\u003eSpecies: \u003cem\u003eHexagonaria\u003c\/em\u003e\u003cbr\u003eAge: Middle Devonian (390 mya)\u003cbr\u003eLocality: Assa Zag, Morocco \u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eSize: 2.5 x 2.5 x .69 inches\u003cbr\u003eWeight: 3.15 oz.\u003c\/p\u003e","brand":"Past \u0026 Present Science and Nature Store","offers":[{"title":"Default Title","offer_id":45462464364681,"sku":null,"price":24.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0364\/6069\/1593\/files\/IMG_59382.heic?v=1774985187","url":"https:\/\/pastpres.com\/products\/colonial-rugose-coral-head","provider":"Past \u0026 Present Science and Nature Store","version":"1.0","type":"link"}