The Aulacostephanidae (Ammonoidea) of the Oxfordian/Kimmeridgian boundary beds (Upper Jurassic) of southern England

A comprehensive analysis of Aulacostephanidae ammonites from the Oxfordian/Kimmeridgian boundary beds in southern England reveals significant insights into the fossil record. The study confirms the established subdivision of the Late Oxfordian Pseudocordata Zone, while also identifying an incomplete sequence in the Early Kimmeridgian Baylei Zone, with only one faunal biohorizon present. This finding contrasts with more complete sequences found elsewhere, such as on the Isle of Skye. The research focuses on well-preserved ammonites from four key areas, including Swindon, Westbury, Bourton, and the Dorset coast near Weymouth, providing systematic descriptions of genera like Ringsteadia, Pictonia, Microbiplices, and Prorasenia. This study enhances our understanding of Jurassic paleontology and stratigraphy.

WRIGHT, J. K. (2010). The Aulacostephanidae (Ammonoidea) of the Oxfordian/Kimmeridgian boundary beds (Upper Jurassic) of southern England. Palaeontology, 53(1), 11–52. https://doi.org/10.1111/j.1475-4983.2009.00916.x