ammonite with hematite - Fossilised animal - cleoniceras sp. - 180 mm - 140 mm

An extremely important fossil group from the Devonian–Cretaceous period. Totally extinct by the end of the Cretaceous, it is thought to have descended from Nautiloidea ancestors. Although belonging to the cephalopod mollusks group, CLEONICERAS is distinguished above all by the shape of its shell, characterized by bilateral symmetry. The shell divides into an undivided anterior region where the animal resided and a posterior region divided into chambers. The line of sutural closure between the chambers is very indicative and facilitates recognition of the species. Moreover, its contour, in the earliest forms rather simple and linear, gradually evolved to the more recent ammonites where it is often very jagged and almost Baroque. Sizes vary: it starts from a few centimeters but can reach up to 10 cm. Being a totally extinct marine species, it is only possible to hypothesize their lifestyle. It is believed that forms with smooth outer shells were swimmers, often predators. Species with more ribbed and ornamented shells were predominantly benthic. Unmissable lot: Impressive and splendid specimen of Cleoniceras sectioned to reveal the extraordinary internal structure, made possible by fossilization through silicification. The dark color typical of black hematite is visible, giving this ammonite a unique charm. Observing the exterior of this beautiful fossil, the characteristic sutural lines of the species are clearly visible, intertwining in a pattern that recalls the sinuous movements of flames. A true natural masterpiece. Pedestal not included; it is made from reclaimed materials used and employed for photographic purposes only.

估價:$302.86

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