phylloceratid

Phylloceratids are a group of extinct marine mollusks that lived during the Jurassic and Cretaceous periods, approximately 199.6 to 66 million years ago. They are characterized by their distinctive, leaf-like shells, which are often referred to as "phylloceratoid" or "phylloceratid" shells. These shells are typically flat, oval, or kidney-shaped, with a smooth or slightly ridged surface. The internal structure of the shell is complex, with a series of chambers that allowed the mollusk to adjust its buoyancy and maintain its position in the water column.

Phylloceratids are believed to have been suspension feeders, filtering small particles of organic matter from the water using their tentacles. They are thought to have lived in shallow, warm seas, and their fossils are commonly found in marine sedimentary rocks from this time period. The most well-known phylloceratid is the genus Phylloceras, which is known for its large, leaf-like shells that can reach up to 30 centimeters in length.

Phylloceratids are an important group of fossils for paleontologists, as they provide valuable information about the evolution of marine mollusks and the history of the oceans during the Mesozoic era. Their distinctive shells have also made them popular among collectors and enthusiasts of fossilized marine life.