The Xenodiscidae are the earliest of the Ceratitida and comprise Middle and Upper Permian genera characterized by compressed, discoidal, evolute shells with rounded to acute venters and commonly with lateral ribs. Sutures are goniatitic to weakly ceratitic.[1]

Xenodiscidae
Temporal range: Guadalupian–Lopingian
Xenodiscus besairiei on display at the Museo Civico di Storia Naturale di Milano
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ceratitida
Superfamily: Xenodiscoidea
Family: Xenodiscidae
Frech, 1902
Genera

The Xenodiscidae, which are part of the superfamily Xenodiscoidea, are derived from the Daraelitidae, a family in the Prolecanitida (ibid). In turn, the Xenodiscidae provided the root stock for the subsequent expansion and diversification of the Ceratitida in the Triassic.

Notes

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  1. ^ Arkell et al, 1957

References

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