Ceratitic

Ceratitic refers to a subclass of extinct cephalopods belonging to the order Ceratitida. These marine mollusks are characterized by their distinctive, often ornate, ammonoid shells. Ceratitids flourished during the Triassic period, appearing around 252 million years ago and going extinct around 201 million years ago at the end of the Triassic-Jurassic boundary. Their fossils are widespread and are important index fossils for dating Triassic rock strata.

The defining feature of ceratitids, and the reason for their name, is their suture line. The suture is the pattern formed where the inner surface of the shell wall meets the outer shell, and it is clearly visible when the shell is sectioned. In ceratitids, the ventral lobe of the suture is trifid (three-lobed), while the lateral lobes are ceratitic, meaning they have a deeply frilled or lobed appearance, but without the additional smaller crenulations found in the later ammonitic suture. This specific suture pattern distinguishes them from earlier ammonoids like goniatites and later ammonites.

Ceratitic shells varied greatly in shape and size, from coiled forms to more evolute or involute shells. They were nektonic organisms, meaning they were active swimmers in the ancient seas. The distribution of ceratitic fossils indicates they inhabited shallow to moderately deep marine environments across the globe. Their evolutionary lineage is a significant part of understanding the development and extinction patterns of cephalopods throughout the Mesozoic Era.