Hildoceratidae

Hildoceratidae is a family of ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian (Jamesoni zone) to lower Bajocian (maybe even upper Bajocian) substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae (= Phymatoceratidae), Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea. The Hildoceratidae are derived from the Polymorphitidae, a family in the Eoderoceratoidea, and gave rise to the Hammatoceratidae and Graphoceratidae.

Hildoceratidae

Hildoceratidae is a family of ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian (Jamesoni zone) to lower Bajocian (maybe even upper Bajocian) substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae (= Phymatoceratidae), Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea. The Hildoceratidae are derived from the Polymorphitidae, a family in the Eoderoceratoidea, and gave rise to the Hammatoceratidae and Graphoceratidae.