Lambdakalkyli

Lambdakalkyli is a genus of extinct ammonites, a type of cephalopod, that lived during the Cretaceous period. The name Lambdakalkyli is derived from the Greek word "λᾰμβδα" (lambda) meaning "lambdoid" and the word "Calkylius", a referencing one of the earliest described ammonites.

Lambdakalkyli fossils have been found in the Upper Cretaceous rock formations of North America and Eastern Europe. These cephalopods were characterized by their distinctive shell shape, which features a lambdoid suture at the junction of the chambers within the shell. This suture is a distinctively curved, suggesting that the shell grew in a scroll-like shape. Adult Lambdakalkyli individuals were relatively small, with shell diameters ranging from 10 to 30 centimeters.

Phylogenetic analysis suggests that Lambdakalkyli belongs to the family Neophyllitidae, a group of advanced, coiled ammonites. The geochronological framework places these fossils in the upper part of the Late Cretaceous, specifically between the Campanian and Maastrichtian epochs. The Lambdakalkyli genus is known primarily through shell fragments and disarticulated specimens. These finds indicate that ammonites like Lambdakalkyli likely dispersed their reproductive particles through with rapid, shell-based reproduction mechanisms.

The study of extinct ammonites, including Lambdakalkyli, contributes to our understanding of Cretaceous marine ecosystems and sheds light on the evolution and diversification of cephalopod species. Further research, incorporating new fossil discoveries and continued phylogenetic analysis, will provide a more complete picture of this fascinating extinct group.