Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which …

Ammonoidea, or ammonoids, constitute one of the most important clades of extinct invertebrate animals. Their lovely shells have long made them favorites of collectors and their fossils have …

The subclass Ammonoidea, a group that is often referred to as ammonites, first appeared about 450 million years ago. Ammonoidea includes a more exclusive group called Ammonitida, also …

Ammonoids (Ammonoidea) are an extinct group of marine invertebrates with an external shell. They were cephalopods, and hence closely related to modern cuttlefish, squid, octopuses and …

Nov 11, 2025 · Ammonoid, any of a group of extinct cephalopods (of the phylum Mollusca), forms related to the modern pearly nautilus (Nautilus), that are frequently found as fossils in marine …

Jul 6, 2023 · Ammonites belong to the subclass Ammonoidea, part of the larger class Cephalopoda, which also includes modern squid, octopus, and cuttlefish. Their closest living …

Jul 28, 2025 · They are classified as the subclass Ammonoidea. These animals were free-swimming predators that navigated ancient seas. Their fossils are found globally in marine …

Ammonoidea is one of three subclasses of cephalopods, the others being Coleoidea (octopuses, squids, cuttlefishes, extinct belemites), and Nautiloidea (nautilus and extinct relatives).

Ammonoidea by Dr. Neale Monks. Ammonoids are a group of externally-shelled cephalopods probably more closely related to the coleoids than to the nautilus.

Phylum Mollusca Class Cephalopoda – Subclass Ammonoidea The phylum Mollusca includes the familiar classes Gastropoda (snails), Pelecypoda (clams, oysters and scallops) and …