| Perisphinctidae Temporal range: Middle - Upper Jurassic |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Ammonoidea |
| Order: | †Ammonitida |
| Superfamily: | †Perisphinctoidea |
| Family: | †Perisphinctidae |
| subfamilies | |
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See text |
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Perisphinctidae is a family of Middle and Upper Jurassic discoidal ammonites in the order Ammonitida. They have a shell morphology that is mostly evolute, typically with biplicate, simple, or triplicate ribbing. Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.[1]
Perisphinctidae[2] were derived from the Stephanoceratidae in the Middle Jurassic Bajocian and ranged into the Tithonian at the end of the Jurassic. This family forms the root stock of the Perisphinctoidea which gave rise directly or indirectly to the other perisphinctoid families.
The Treatise on Invertebrate Paleontology (Part L, 1957) includes the subfamilies Leptosphinctinae, Zigzagiceratinae, Pseudoperisphincinae, Perisphinctinae, Aataxioceratinae, Pictoniidae, Aulocostephaninae, Virgostephaninae, Dorsoplanitinae, and Virgatitinae in the Perisphictidae.[1] Donavan et al [2] also recognizes the Leptosphinctinae, Zigzagiceratinae, Pseudoperisphincinae, and Perisphinctinae but leaves out the others, adding instead the Epipletoceratinae, and Idoceratinae
Epipeltoceratinae is based on Epipletoceras, a genus in the Aspidoceratidae in the Treatise, (subfamily Peltoceratinae). The Idoceratinae is based on Idoceras, a genus in the, according to the Treatise, polyphyletic Ataxioceratinae. Donavan et al separates the Aulocostephaninae, including the Pictoniidae, as the Aulocosphanidae. The Virgostephaninae, Dorsoplanitinae, and Virgatitinae are thereby separated also as separate families. all from the Upper Jurassic.