Cephalopoda - Ammonitida - Perisphinctidae
Alternative spelling: Siemiradzkia (Prevalia)
Parent taxon: Gracilisphinctes according to N. V. Besnosov and V. V. Mitta 1993
See also ZatoĊ 2010
Sister taxa: Procerites (Procerites), Procerites gallus, Procerites hodsoni, Procerites imitator, Procerites irregularis, Procerites laeviplex, Procerites pseudoperspicuus, Procerites pseudorjazanensis, Procerites quercinus, Procerites tmetolobus, Procerites verciacensis, Gracilisphinctes andranomantsyensis, Gracilisphinctes arkelli, Gracilisphinctes (Gracilisphinctes), Gracilisphinctes lemoinei
Subtaxa: Gracilisphinctes (Prevalia) thressa Siemiradzkia (Prevalia) stephanovi
Type: Siemiradzkia (Prevalia) thressa
Ecology: fast-moving nektonic carnivore
Distribution:
• Jurassic of Uzbekistan (3 collections)
Total: 3 collections each including a single occurrence