RT Journal Article T1 La subfamilia Ataxioceratinae (Ammonoidea) en el Oxfordiense Superior de la Provincia Submediterránea: origen y evolución T1 The Subfamily Ataxioceratinae (Ammonoidea) from Upper Oxfordian of the Submediterranean Province: origin and evolution A1 Pérez Urresti, I. A1 Bello Villalba, J. A1 Meléndez Hevia, Guillermo AB The subfamily Ataxioceratinae Buckman arises at the turn of the Middle-Upper Oxfordian (Upper Jurassic) in the South-European Platform, spreading mostly throughout the Submediterranean province during Upper Oxfordian-Lower Kimmeridgian times. The genus Orthosphinctes Schimdiwoíf, type-species Ammonites tizianí Omt, is the first genus of this family and is first recorded al the Bifurcatus-Bimammatum Zone boundary in most of the West-Tethys areas. The successive forms of this genus appear fairly well-represented all across the Iberian Range (E Spain), allowing the recognition of many Orthosphinctes biohorizons within the classical biosiratigraphic scheme for the Upper Oxfordian in the Submeditarranean Province. The origin of the genus Subnebrodites at the base of the Planula Zone is proposed from the main Orthosphinctes stem via the 'intermediate', synthetic form O. fontannessi (Chofpaj) PB Sociedad Geológica de España YR 1996 FD 1996 LK http://hdl.handle.net/10272/11406 UL http://hdl.handle.net/10272/11406 LA spa DS Repositorio Institucional de la Universidad de Huelva RD 30 may 2026