Early perisphinctid ammonites from the early/late Bajocian boundary interval (Middle Jurassic) from Lókút, Hungary - 28/06/12
Abstract |
On the basis of an evaluation of data from the literature and a systematic study of rich material from the Stephanoceras humphriesianum and Strenoceras niortense Zones of the Bakony Mountains (Transdanubian Hungary), it is supported that leptosphinctids, the earliest Perisphinctidae s.str., most probably originated from Western Tethyan Stephanoceratidae. This descent is documented here with stephanoceratids very close to earliest leptosphinctids (Phaulostephanus exilis nov. sp. and Ph. apertus nov. sp.) and with very early leptosphinctids showing mixed stephanoceratid and perisphinctid characters. This latter group is represented by species described previously elsewhere plus new species (Stephanosphinctes tuberculatus nov. sp., a macroconch, and Leptosphinctes (Cleistosphinctes) umbilicatus nov. sp., a microconch). Possible migration routes of early perisphinctids are discussed and the Hispanic Corridor is suggested as the most probable.
Le texte complet de cet article est disponible en PDF.Keywords : Ammonoidea, Perisphinctidae, Bajocian, Hungary, Systematics, Origins
Plan
Corresponding editor: Pierre Hantzpergue. |
Vol 45 - N° 3
P. 285-295 - mai 2012 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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