The world’s largest ammonite, Parapuzosia (P.) seppenradensis (Landois, 1895), has fascinated the world since the discovery in 1895 of a specimen measuring 1.74 metres (m) in diameter near Seppenrade in Westfalia, Germany. Subsequent findings of this taxon have been rare. For this study (Ifrim et al., 2021), the historical specimens have been revised, and abudant material from England and Mexico was documented. It comprises 154 specimens of large (< 1 m diameter) to giant (> 1m diameter) Parapuzosia from the Santonian and lower Campanian, mostly with stratigraphical information. High-resolution integrated stratigraphy allows for precise trans-Atlantic correlation of these occurrences. The Tepeyac section in northeastern Mexico, where 66 specimens of diameters from 10 to 150 cm were found in their original layer was documented with integrated stratigraphy. With 330 ammonoids and >100 inoceramids, among other fossils, it is the section with the richest fossil record in that interval. It has become Associated Stratotype Section and Point for the base of the Campanian (Gale et al. 2023). The high- resolution correlation allows for further insight into the palaeobiology, evolution and dispersal of worlds largest ammonite
References
Gale, A., et al. 2023. The Global Boundary Stratotype Section and Point (GSSP) of the Campanian Stage at Bottaccione (Gubbio, Italy) and its Auxiliary Sections: Seaford Head (UK), Bocieniec (Poland), Postalm (Austria), Smoky Hill, Kansas (U.S.A), Tepayac (Mexico). Episodes. doi: 10.18814/epiiugs/2022/022048.
Ifrim, C. et al. 2021. Ontogeny, Evolution and palaeobiogeographic distribution of Parapuzosia (P.) seppenradensis, the world's largest ammonite. PLoS ONE 16, e0258510. doi: 10.1371/journal.pone.0258510.