The genus Gonioclymenia (Ammonoidea; Late Devonian) in Central Europe

摘要

The stratigraphically important Late Devonian ammonoid genus Gonioclymenia is revised based on material from the type regions in the Franconian Forest and the Rhenish Mountains. Based on differences in conch shape, suture line and particularly in sculpture, two Franconian species (G. speciosa, G. subcarinata) and five Rhenish species (G. subcarinata, G. praematura, and the new species G. pricei, G. wunderlichi and G. parabolica) can be separated. Gonioclymenia shows distinct palaeogeographical patterns; all the Central European species differ, in their narrower umbilicus and the higher coiling rate, from the species known from the South Urals. Based on these conch shape differences, three new Uralian species G. asperornata, G. mediornata and G. facetornata are introduced for material previously attributed to Central European species. A stratigraphical succession of species from the Rhenish Mountains is documented based on a weakening of the sculpture through the Clymenia laevigata, Ornatoclymenia ornata and Piriclymenia piriformis zones.