Arnioceras Semicostatum

Arnioceras semicostatum fossil ammonite specimens embedded within limestone matrix from the Jurassic rocks of the, East Yorkshire, UK. Arnioceras is an extinct genus of ammonite which existed during the lower Lias stage of the Jurassic period around 180 million years ago. Their shells represent the typical ammonite form and shape one would expect and is evolute, bearing pronounced, sharp ribs with a ventral keel without furrows. Under these ribs some specimens may show the ammonitic suture lines, which are much easier to see with aid of magnification. Lime all ammonoids, they were aquatic in lifestyle and possessed a soft squid like body, part of which was housed and protected within the shell, which was a form of defence against predators. Over all, the species was distributed world wide with specimens found Europe, South Asia, and the Americas, they exhibit a grey sometimes faded brown colouration and are on a solid limestone matrix making them fairly solid and less prone to damage. They are excellent specimens and suitable for those with an interest in geology, fossils or educational use and for collectors and come available in various optional sizes and will arrive in a card tray with an information label.