RARE Argonauticeras argonautus Fossil Ammonite | Aptian Cretaceous | Madagascar | Authentic Specimen with COA

Description Available here is a RARE and visually striking fossil ammonite of the species Argonauticeras argonautus, sourced from Madagascar and dating to the Aptian stage of the Early Cretaceous period (approximately 125 to 113 million years ago). This exceptional ammonite specimen is highly desirable due to its evolutionary and geographic significance, and displays classic morphological traits. You will receive the exact fossil pictured, accompanied by a 1cm scale cube in the photo for precise sizing. This is a 100% genuine fossil and is supplied with a Certificate of Authenticity. Geological & Scientific Information: Species: Argonauticeras argonautus Type: Fossil Ammonite (extinct marine cephalopod) Geological Period: Cretaceous Stage: Aptian (approx. 125–113 million years ago) Location Found: Madagascar Order: Ammonitida Superfamily: Desmoceratoidea Family: Douvilleiceratidae Morphological Features: Argonauticeras is recognised for its evolute shell, broad whorls, and fine ribbing extending radially from the umbilicus. The ribs may form subtle nodes and undulations that are distinctive for this genus. This specimen displays excellent preservation, with pronounced suture patterns and intact surface detail. Depositional Environment: Likely deposited in a shallow marine shelf setting, where calcareous mud and sediment aided fossil preservation. The region that is now Madagascar was part of the ancient Gondwanan landmass during the Cretaceous, contributing to unique ammonite faunal assemblages. Notable: Argonauticeras species are notable for their unique shell ornamentation and are occasionally used in biostratigraphic correlation in southern hemisphere Cretaceous deposits. Additional Notes: Argonauticeras ammonites are increasingly rare on the market, especially in such well-preserved condition. This fossil is ideal for collectors of Cretaceous ammonites, paleontologists, or anyone seeking a display-worthy piece of Madagascar’s prehistoric marine life. Why Buy From Us? 100% authentic fossils with accurate identification Includes a Certificate of Authenticity You receive the exact fossil pictured Perfect for education, collection, or display Add this rare and beautiful Argonauticeras argonautus ammonite fossil to your collection and own a genuine piece of Early Cretaceous history from Madagascar!