Search results for "Ceratitida"
showing 3 items of 3 documents
Guodunites, a low-palaeolatitude and trans-panthalassic Smithian (Early Triassic) ammonoid genus
2009
11 pages; International audience; Based on new, bed-rock controlled material from Oman and Utah, USA, the Early Triassic genus Guodunites, which was recently erected on the basis of scarce specimens from northwestern Guangxi, South China, is now shown to be a representative of Proptychitidae. This solves the question of the previously unknown phylogenetic affinity of this genus. The genus is restricted to the late middle Smithian, and to date, its biogeographical distribution comprises Oman, South China and Utah, thus indicating an essentially low palaeolatitudinal distribution during the Early Triassic. Its palaeobiogeographical distribution further strengthens the existence of significant…
Evolutionary trends of Triassic ammonoids.
2015
The Triassic represents a key interval in the evolutionary history of ammonoids. Characterized by the dominance of the Ceratitida with their typical suture line indented on the lobes only, the Triassic quasi-monophyletic clade shows a remarkable biostratigraphic and geographic record. However, very few studies have thoroughly investigated their evolutionary trends, except for taxonomic richness. Although Triassic ammonoids show a very large range of morphologies, suture complexity and adult size, little is currently known about their trends, except for peculiar time intervals or taxonomic groups. Nevertheless, it seems that taxonomic diversity and morphological disparity of Triassic ammonoi…
Biostratigraphy of Triassic Ammonoids
2015
The Triassic is a turning point in the evolutionary history of ammonoids, characterized by the flourishing Ceratitida and the appearance of the first heteromorphs. Following the end-Permian mass extinction, ammonoids were among the first groups to rediversify by producing many new taxa. Already in the late nineteenth century, the still currently recognized Triassic stages and substages were introduced. The historical development of Triassic ammonoid biostratigraphy is a good example of worldwide cooperation between many geographically-diverse research groups, which initially began in Germany and the European Alps. This cooperation was then extended to North America, Transcaucasia, North Ind…