RT Journal Article
T1 New species of Franchia and Protozigzagiceras (Ammonoidea, Middle Jurassic): The phyletic origin of Zigzagiceratinae
A1 Fernández López, Sixto Rafael
A1 Pavia, Giulio
AB Three genera and seven species belonging to thesubfamily Zigzagiceratinae (family Perisphinctidae) aredescribed from the Lower Bathonian of France and SaudiArabia. Intraspecific dimorphism is recognized. A revision ofthe genus Franchia proposed by Sturani (1967), based on thesyntypes and new specimens from south-east France, ispresented. Franchia arkelli Sturani, Franchia subalpina sp.nov., Protozigzagiceras torrensi (Sturani), Protozigzagicerastethycum sp. nov., Protozigzagiceras flexum sp. nov. and Protozigzagicerasdensum sp. nov. are described from the Digne–Castellane region of south-east France. Megazigzagicerassubarabicum, gen. et sp. nov. is described from the Dharmaregion of Saudi Arabia. The successive Early Bathonian speciesof Franchia and Protozigzagiceras herein identified inWest Tethyan areas, as members of the Mediterranean–CaucasianSubrealm, formed lasting separate peramorphoclinescharacterized by increasing hydrodynamic coiling of theshell. In contrast, rapid proterogenesis originated and diversifiedthe earliest Bathonian zigzagiceratin lineages, givingpaedomorphic members, commonly neotenic and more scarcelyprogenetic. Procerites–Siemiradzkia seems to be the oldestzigzagiceratin member in the French Subalpine, Iberianand Lusitanian basins, branched off by paedomorphosis fromleptosphinctins at the Bajocian–Bathonian transition. TheMediterranean–Caucasian genera Franchia, Zigzagiceras, Zigzagitesand Wagnericeras branched from successive species ofProtozigzagiceras, in turn, a direct derivative of Procerites.The oldest lineages of the clade Zigzagiceratinae evolved byiterative, rapid, paedomorphic changes and additional, lasting,peramorphic modifications during the Early Bathonian.
PB Blackwell Publishing Ltd
SN 0031-0239
YR 2013
FD 2013
LK https://hdl.handle.net/20.500.14352/33457
UL https://hdl.handle.net/20.500.14352/33457
LA eng
DS Docta Complutense
RD 30 abr 2024