THIS IS A DRAFT - INFORMATION MAY BE INCORRECT
In the middle Famennian there occurred the fastest, shortest-lived burst of evolution in Paleozoic ammonoid history: the radiation of the Clymeniida. This unusual goniatitic group differed from all other ammonoids in possessing a dorsal siphuncle, contrary to a ventrally located siphuncle in all other ammonoids. Whether this was a key to their success is not known, but more than 60 clymeniid genera evolved during that period. Clymeniida measured about 4cm in diameter and is restricted to Europe, North Africa and possibly Australia. It probably adapted to a predatory role high in the water column.
- Gonioclymeniaceae
- Hexaclymeniidae - includes: Soliclymenia (had a triangular form and was smaler - about 2cm across)
- Acanthoclymeniidae
- Gonioclymeniidae - includes: Gonioclymenia, Kalloclymenia
- Wocklumeriidae - includes: Wocklumeria, Epiwocklumeria
- Glatziellidae
- Clymeniaceae
- Clymeniidae - includes: Clymenia, Platyclymenia
- Cyrtoclymeniidae - includes: Cymaclymenia, Cyrtoclymenia, Genuclymenia, Kosmoclymenia
- Rectoclymeniidae
- Parawocklumeriaceae
- Parawocklumeriidae