Dactylioceras was a widespread genus of ammonites from the Lower Jurassic period, approximately 180 million years ago (mya).
In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.3 Ma to around 168.3 Ma. The Bajocian age succeeds the Aalenian age and precedes the Bathonian age.
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma. The Bathonian age succeeds the Bajocian age and precedes the Callovian age.
Stephanoceras is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian. It is the type genus of the family Stephanoceratidae.
Echioceras is an extinct genus of ammonites from the Early Jurassic of Europe and North America.
Cadomites is an extinct ammonite genus from the superfamily Stephanoceratoidea that lived during the Middle Jurassic.
Durotrigensia is a genus of ammonites (Ammonitida) in the perisphinctoid family Parkinsoniidae.
Okribites is a perisphinctoidean ammonite from the middle Jurassic of the Republic of Georgia. It is assigned to the family Parkinsoniidae, a group of strongly but evenly ribbed evolute, commonly discoidal ammonites. Parkinsonia is a related genus.
Nannolytoceras is an extinct genus of lytoceratid ammonite, family Lytoceratidae, with a stratigraphic range extending from the Bajocian age to Bathonian age.
Hyperlioceras is an extinct genus of cephalopod included in the ammonitid family Graphoceratidae that lived during the Bajocian stage of the Middle Jurassic. The type species is Hyperlioceras discites
Psiloceras is an extinct genus of ammonite. Psiloceras is among the earliest known Jurassic ammonites, and the appearance of the earliest Psiloceras species form the definition for the base of the Jurassic. Unlike most earlier ammonites, which had complex shell shapes and ornamentation, Psiloceras had a smooth shell.
Phylloceras is an extinct genus of ammonoid cephalopods belonging to the family Phylloceratidae. These nektonic carnivores lived from Early Jurassic to Late Cretaceous.
Lytoceras is an ammonite genus that was extant during most of the Jurassic and Cretaceous periods, and is the type genus for the family Lytoceratidae. These cephalopods were fast-moving nektonic carnivores.
Reineckeia is an extinct genus of ammonoid cephalopods belonging to the family Reineckeiidae.
Lithacoceras is an extinct Ammonite cephalopod genus included in the superfamily Perisphinctoidea. These fast-moving nektonic carnivores lived during the Jurassic period, from the Oxfordian age to the Tithonian age.
Cardioceras is an extinct ammonite genus belonging to the family Cardioceratidae. These fast-moving nektonic carnivores lived during the Jurassic period, Oxfordian age.
Pseudopeltoceras is a genus of perisphinctoid ammonites belonging to the family Perisphinctidae.
Skirroceras bayleanum is a Stephanoceratacean (ammonite) species belonging to the family Stephanoceratidae.
Mercaticeras is an extinct genus of ammonites belonging to the family Hildoceratidae.
Pictonia is an extinct ammonoid cephalopod genus belonging to the family Aulacostephanidae. These fast-moving nektonic carnivores lived during the Jurassic period, Kimmeridgian age.
