lyratum

Lyratum is a genus of extinct ammonite mollusks that lived during the Late Jurassic period, approximately 150 million years ago. As members of the subclass Ammonoidea, lyratum ammonites are characterized by their coiled, chambered shells, which are divided into numerous segments separated by septa. Their shells often exhibit intricate ribbing or patterning, which varies across species within the genus.

The fossil record of lyratum provides valuable insights into marine ecosystems of the Jurassic period. These organisms thrived in warm, shallow seas and are frequently found in sedimentary rock formations that were once seafloor environments. The distinctive features of lyratum shells, such as their ornamentation and shell morphology, are used by paleontologists to identify and classify fossils and to understand evolutionary relationships among ammonites.

Lyratum ammonites are believed to have been active predators, feeding on smaller marine animals such as plankton, small fish, and other invertebrates. Their buoyancy control, enabled by the chambered shells, allowed them to navigate different depths within their marine habitats. The evolutionary history of lyratum shows a diversification that aligns with environmental changes during the Jurassic epoch, but like many ammonite groups, they faced extinction at the end of the Cretaceous period, approximately 66 million years ago.

Today, lyratum fossils are important tools for biostratigraphy, helping geologists date and correlate sedimentary layers. Their fossilized shells are often found in museum collections and are studied for clues about ancient marine environments and the evolutionary history of cephalopods.