fossils 3.1

These flashcards cover key terms and concepts related to cephalopods and their characteristics, as introduced in the lecture on fossils.

Cephalopoda

A class of molluscs that includes living octopus, squid, cuttlefish, and nautilus, as well as extinct forms like ammonoids and belemnites.

Buoyancy

The ability of a cephalopod's chambered shell to float due to the air replacing water in its chambers.

Sexual dimorphism

The consistent co-occurrence of large and small individuals in cephalopods, suggesting a distinction between male (microconch) and female (macroconch).

Nautiloidea

A subclass of cephalopods characterized by an external, usually coiled shell, central siphuncle, and simple suture lines.

Ammonoidea

A subclass of cephalopods with an external shell, usually spiral, complex suture lines, and were prominent from the Devonian to Cretaceous periods.

Heteromorph ammonites

Ammonites that exhibit unusual shell shapes and characteristics.

Aptychi

Bivalved calcareous plates associated with ammonite apertures, possibly functioning as a jaw apparatus or protective operculum.

Phragmocone

A chambered structure in cephalopod shells that helps in buoyancy.

Mollusc

A phylum of invertebrates that cephalopods belong to, characterized by a soft body, mantle, and often a hard shell.

Hypothetical Archimollusc

A theoretical ancestor of all molluscs, representing the generalized morphology of molluscs.

Radula

A specialized feeding organ found in many molluscs, used for scraping or cutting food.