{"product_id":"middle-jurassic-macrocephalites-sp-ammonite-approx-165-million-years-old","title":"Middle Jurassic Macrocephalites sp. Ammonite — Approx. 165 Million Years Old","description":"\u003ch2\u003eA spiral from the Middle Jurassic\u003c\/h2\u003e\n\u003cp\u003eThis beautifully ribbed ammonite is provisionally identified as \u003cem\u003eMacrocephalites\u003c\/em\u003e sp., a member of the Macrocephalitidae. Its coiled form, dense radial ribs and substantial shell are characteristic of this Middle Jurassic group.\u003c\/p\u003e\n\u003ch2\u003eAround 165 million years old\u003c\/h2\u003e\n\u003cp\u003eThe specimen most likely dates from the Callovian Stage of the Middle Jurassic, approximately 165 million years ago. Ammonites evolved rapidly, making their shells valuable markers for dating Jurassic marine rocks. Closely related \u003cem\u003eMacrocephalites\u003c\/em\u003e specimens are recorded from the Bathonian–Callovian interval by the British Geological Survey. \u003c\/p\u003e\n\u003ch2\u003eWhere was it found?\u003c\/h2\u003e\n\u003cp\u003eThe exact collecting locality of this specimen is not recorded. Related \u003cem\u003eMacrocephalites\u003c\/em\u003e fossils are known from marine Jurassic rocks across Europe, India and other former Tethyan sea regions. Because its provenance is unknown, no specific country of origin is being claimed. \u003c\/p\u003e\n\u003ch2\u003eHow rare is it?\u003c\/h2\u003e\n\u003cp\u003e\u003cem\u003eMacrocephalites\u003c\/em\u003e was a widespread genus, so it would be misleading to describe this as a scientifically rare species. However, every fossil is individually unique, with its own pattern of ribs, mineral staining, weathering and preservation. This specimen is a small, tangible archive of Jurassic time.\u003c\/p\u003e\n\u003ch2\u003eDetails\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApprox. dimensions: 6 × 5 × 2 cm\u003c\/li\u003e\n\u003cli\u003eWeight: 81 g\u003c\/li\u003e\n\u003cli\u003eIdentification: probable \u003cem\u003eMacrocephalites\u003c\/em\u003e sp.\u003c\/li\u003e\n\u003cli\u003eAge: Middle Jurassic, probable Callovian\u003c\/li\u003e\n\u003cli\u003eProvenance: unknown\u003c\/li\u003e\n\u003cli\u003eCondition: natural weathering, mineral staining and damage\/loss around the outer edge\/apertural area\u003c\/li\u003e\n\u003cli\u003eThe photographs show the exact specimen\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eExact ammonite identification depends heavily on locality, shell proportions and ornament, so the genus-level wording is intentionally cautious. \u003c\/p\u003e","brand":"Deep Time Atelier","offers":[{"title":"Default Title","offer_id":49016614846689,"sku":"DTA-AMM-MACRO-001","price":89.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0841\/7892\/7841\/files\/20260831-P8310045_9d58f7ad-2285-4bd5-82ab-267db2d6148b.jpg?v=1788259395","url":"https:\/\/deeptimeatelier.com\/products\/middle-jurassic-macrocephalites-sp-ammonite-approx-165-million-years-old","provider":"Deep Time Atelier","version":"1.0","type":"link"}