What are the 3 major groups of cephalopods?

A highly intelligent group of ocean dwelling creatures, the living cephalopods include the eight-armed octopuses, the ten-armed squids and cuttlefishes, and the shelled chambered nautiluses.

What are the two characteristics of cephalopods?

Cephalopods are characterized by a completely merged head and foot, with a ring of arms and/or tentacles surrounding the head. The arms, tentacles, and funnel are all derivatives of the foot.

What is the structure of a cephalopod?

All cephalopods have an internal cartilaginous covering of the consolidated ganglia of the nervous system. In all except ammonites and nautiloids, it constitutes a cranium. Various other skeletal supports are found at the base of the fins and in the “neck,” gills, and arms.

What are the 4 orders of cephalopods?

Classification

• †Order Belemnoidea (belemnites)
• Order Sepioidea (cuttlefishes and bottle-tailed squids)
• Order Teuthoidea (squids)
• Order Vampyromorpha.
• Order Octopoda (octopuses)

Do all cephalopods have 3 hearts?

Cephalopods have not one but three hearts. The central heart pumps oxygenated blood to the body, while the other two hearts are responsible solely for the gills.

What is the oldest cephalopod?

Tannuella. Tannuella is the oldest fossil to have been assigned to the cephalopods, dating from the Early Cambrian (Atdababian and Botomian), ~522 million years ago. Its position in this group is suggested based on its shape and the presence of chambers.

What are the main types of cephalopods?

Cephalopods are members of a class of marine animals that includes octopuses, squid, cuttlefish and nautiluses.

What is the largest cephalopod in the world?

Squids
Squids are the largest living cephalopods in terms of each of mantle length, total length, and mass, with the largest species by at least two of these measures being the colossal squid, Mesonychoteuthis hamiltoni.