Heterometridae

Heterometridae is a family of marine invertebrates belonging to the order Comatulida, commonly known as feather stars. These echinoderms are characterized by their distinctive feathery arms, which they use for locomotion and filter feeding. Unlike their more sedentary relatives, sea lilies, feather stars are free-swimming and can move across the seabed or through the water column.

The family Heterometridae is distinguished by several morphological features, primarily related to the structure of their cirri (small, prehensile appendages) and their arms. The number of arms can vary significantly among species, ranging from five to over forty. Their bodies, or central disc, are typically small and often hidden by the bases of their arms.

Heterometridae species are found in tropical and subtropical waters worldwide, inhabiting a variety of marine environments from shallow coral reefs to deeper abyssal plains. They are suspension feeders, capturing small planktonic organisms and organic particles from the water column using the tube feet located along their arms. The diversity within Heterometridae reflects adaptations to different ecological niches and geographical distributions. Scientific classification places this family within the class Crinoidea, subclass Articulata, and order Comatulida.