A new species of the ammonite genus Physodoceras Hyatt (Aspidoceratidae) from the Hybonotum Zone (Lower Tithonian) of Southern Germany, with comments on the phylogeny of the genus

Abstract We here introduce a new species of the aspidoceratid genus Physodoceras, P. widerai n. sp., the corresponding microconchs of which are represented by Sutneria eugyra Barthel. The Physodoceras succession of the upper Kimmeridgian (Pseudomutabilis to Beckeri zones) to Lower Tithonian (Hybonotum to Ciliata zones) is summarized. Lectotypes are designated for Perisphinctes casimirianus Fontannes, Aspidoceras episoides Fontannes, Ammonites hoplisus Oppel, and Ammonites aporus Oppel.