Pedicellariae
Encyclopedia
A pedicellaria is a small wrench or claw-shaped structure commonly found on Echinoderm
s, particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organism
s, and other debris in conjunction with the ciliated epidermis present in all echinoderms. Pedicellariae in some taxa, such as the deep-sea Brisingida, and the Antarctic Labidiaster are known to function in food capture. In forcipulate sea stars, each pedicellaria is typically composed three forceps
-like valves. Other asteroids can have pedicellariae composed of only two components. In some asteroid sea stars pedicellariae are present around the base of a spine
or on the surface of the animal's body. In other sea stars, they are present in pits on the abactinal, marginal, or actinal surface; oftentimes on the adambulacral plate adjacent to the tube foot furrow.
Echinoderm
Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....
s, particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s, and other debris in conjunction with the ciliated epidermis present in all echinoderms. Pedicellariae in some taxa, such as the deep-sea Brisingida, and the Antarctic Labidiaster are known to function in food capture. In forcipulate sea stars, each pedicellaria is typically composed three forceps
Forceps
Forceps or forcipes are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term 'forceps' is used almost exclusively...
-like valves. Other asteroids can have pedicellariae composed of only two components. In some asteroid sea stars pedicellariae are present around the base of a spine
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
or on the surface of the animal's body. In other sea stars, they are present in pits on the abactinal, marginal, or actinal surface; oftentimes on the adambulacral plate adjacent to the tube foot furrow.