axopodal

An axopodal is a long, slender, and usually temporary projection found on certain protozoa, particularly those belonging to the class Radiolaria. These structures are distinct from pseudopods, which are more general-purpose extensions of the cytoplasm used for locomotion and feeding. Axopods are characterized by an internal axial filament, which is a rigid rod composed of microtubules. This filament provides structural support and determines the shape of the axopod, allowing it to maintain a consistent and often radiating form.

The primary functions of axopods are related to feeding and sensing. They are used to capture small prey, such as bacteria and other planktonic organisms, by ensnaring them in a sticky mucus that covers the axopod's surface. Once captured, the prey is slowly moved towards the cell body for digestion. Additionally, axopods can play a role in buoyancy, helping the organism to remain suspended in the water column. The arrangement and length of axopods can vary significantly between different species, contributing to their identification and classification. They can be retracted or extended as needed by the organism.