Species Description: Luidia clathrata is a member in the family Luiidae. This sea star has a small central disc surrounded by five long, flat arms. The arms contain tube feet which are used for locomotion (Pomory and Lares 2000). The arms of the gray sea star are 2 - 3 times the size of the disc diameter. The surface of the body is covered in plates. The upper surface of the body ranges from gray to light brown, rose or salmon color, although most living specimens are gray. This species differs from other Luidia species by the dark gray or black stripe on the dorsal midline of each arm (Hendler et. al. 1995). Behavioral studies of L. clathrata have shown that this species displays negative phototaxis and will burrow in the sand to avoid light (Hendler et. al. 1995).
Regional Occurrence: Luidia clathrata occurs from the Virginia coast to Brazil in the Atlantic Ocean and as far west as Alabama in the Gulf of Mexico (McClintock and Lawrence 1985, Miller and Lawrence 1999). The gray sea star is found at depths from 0-100 m but usually encountered in shallow-waters less than 40 m, on soft bottom habitats (Hendler et. al. 1995, Pomory and Lares 2000).
IRL Distribution: The gray sea star is common in the IRL and other Florida waters (Miller and Lawrence 1999).
Age, Size, Lifespan: Luidia clathrata is large, growing to 20 - 30 cm in length (Hendler et al. 1995).
Abundance: Populations can be very dense (McClintock and Lawrence 1985, Watts and Lawrence 1990).
Regeneration: The arms of Luidia clathrata can be lost as a result of predation. This process can affect the ability of an individual to survive because the arms are important for locomotion, feeding, energy storage, and reproduction (Lawrence et al. 1986, Pomory and Lares 2000). Regeneration of the exposed end of the damaged arm begins by immediately sealing the damaged area. A new tip appears in approximately one week (Lawrence et al. 1986). The average rate of regeneration in field collected specimens has been reported to be approximately 3.7 mm per month. Arms appear to regenerate at a quicker rate until they reached 40-50% of the total length (Pomory and Lares 2000). In laboratory experiments, although the rate of regeneration was shown to be a function of food availability, regeneration did occur even when the animal was starved (Lawrence et al. 1986).
Reproduction: Similar to its close relative Luidia senegalensis, L. clathrata spawns annually (Heinz and Lawrence 1994).
Embryology: The gray sea star has one larval stage before metamorphosis, a large bipinnaria larva (2 mm long) that is competent (ready for metamorphosis) within one month.
Temperature: There are no studies specifically addressing the temperature tolerance of the gray sea star.
Salinity: Luidia clathrata is reported to tolerate salinities as low as 14 ppt (Hendler et al. 1995).
Trophic Mode: The gray sea star is a forager that can feed on a variety of different taxa including foraminiferans, nematodes, ostracods, gastropods, bivalves, crustaceans, as well as sediment and detritus. In Tampa Bay, Florida, Luidia clathrata prefers the bivalve Mulinia lateralis (McClintock and Lawrence 1985). This sea star obtains its food by ingesting sand and mud and then straining this material through oral spines (Hendler et al. 1995). When it is buried, it will evert its stomach to feed on detritus (Hendler et al. 1995).
Associated Species: Adults have a commensal polychaete worm, Podarke obscura Verrill, living in the ambulacral groove (Miller and Lawrence 1999).
Heinz JL and JM Lawrence. 1994. Acclimation of gametes to reduced salinity prior to spawning in Luidia clathrata (Echinodermata: Asteroidea). Marine Biology 120:443-446.
Hendler G, Miller JE, Pawson DE, and PM Kier. 1995. Sea Stars, Sea Urchins, and Allies. Smithsonian Institution Press, Washington, DC. pg. 68-71.
ITIS. Integrated Taxonomic Information System. Available online.
Lawrence JM, Klinger TS, McClintock JB, Watts SA, Chen C-P, Marsh A, and L Smith. 1986. Allocation of nutrient resources to body components by regenerating Luidia clathrata (Say) (Echinodermata: Asteroidea). Journal of Experimental Marine Biology and Ecology 102:47-53.
McClintock JB and JM Lawrence. 1985. Characteristics of foraging in the soft-bottom benthic starfish Luidia clathrata (Echinodermata: Asteroidea): prey selectivity, switching behavior, functional responses and movement patterns. Oecologia 66:291-298.
Miller SR and JM Lawrence. 1999. Gonad and pyloric caeca production nine-armed starfish Luidia senegalensis off the southwest Florida gulf coast during the annual reproductive cycle. Bulletin of Marine Science 65:175-184.
Pomory CM and MT Lares. 2000. Rate of regeneration of two arms in the field and its effect on body components in Luidia clathrata . Journal of Experimental Marine Biology and Ecology 254:211-230.
Watts SA and JM Lawrence. 1990. The effect of temperature and salinity interactions on righting, feeding and growth in the sea star Luidia clathrata. Marine Behavior and Physiology 17:159-165.
Aboral: In a direction away from the mouth; the part of the body opposite the mouth.
Anal Cone: In crinoids and echinoids, a fleshy projection bearing the anus at its apex; also known as an anal tube.
Apical System: In echinoids, a ring of specialized skeletal plates, including the genital plates and ocular plates; usually located on the highest point of the test.
Arm: In asteroids, crinoids, and ophiuroids, a movable, jointed ambulacral projection, distal to the disk or calyx that carries a radial branch of the water vascular system and the nervous system; sometimes called a ray.
Basket: One of several types of microscopic skeletal ossicles in holothuroids; minute cup-shaped ossicle, usually with four projections.
Button: One of several types of microscopic skeletal ossicles in holothuroids; minute ossicle with four perforations; may be smooth or knobbed.
Disk: The round or pentagonal central body region of ophiuroids and asteroids; see also Terminal Disk.
Distal: In a direction away from the center of the body; for example, toward the tip of the arm in asteroids or the tip of a spine in echinoids.
Dorsal: In echinoderms, this term is variously applied; in asteroids, ophiuroids and echinoids it usually refers to the surface of the body that is opposite the mouth, the surface that is uppermost; in holothuroids, with mouth and anus opposite ends of the cylindrical body, the uppermost surface is considered dorsal; in crinoids, the surface opposite the mouth in considered dorsal by convention, even though it is functionally the ventral (lower) side.
Echinulate: Something spiny or prickly, usually referring to the microscopic texture of a skeletal element such as a spine.
Hermaphrodism: A condition in organisms whereby one individual possesses both functional male and female reproductive structures; hermaphroditic individuals may express both sexes simultaneously, alternately, or sequentially.
Interambulacral Area: An oral or aboral section of the body lying between two ambulacra; in interradius; also known as an interambulacrum.
Interradial: Referring to interambulacral areas of the body; interradius and interradii also commonly used.
Oral: In a direction toward the mouth; a part of the body on the same surface as the mouth.
Oral Papillae: In ophiuroids, small plates at the edge of the mouth, attached to the edges of the jaw plate and/or to the aboral shield; may be variously shaped, from spine-like to scale-like.
Papillae: In holothuroids, specialized dorsal tube feet that lack a suckered tip; in ophiuroids, certain skeletal elements of the jaws or disk.
Papillate: Covered with papillae.
Papillose: Covered with papillae.
Pedicellariae: Small stalked or unstalked pincer-like organs on the body of asteroids and echinoids, used for defense and grooming.
Peltate: Shield-shaped; used to describe the tentacles of some holothuroids.
Perforated Plate: One of several types of microscopic skeletal ossicles in holothuroids; sieve-like and widespread; may also be found in other echinoderm classes, especially in juvenile individuals.
Periproct: In echinoids, a flexible region surrounding the anus, which consists of a membrane containing embedded plates and often bearing spines and pedicellariae.
Plates: One of several types of skeletal elements in echinoderms; tabular structures with a characteristic shape and a fixed position.
Primary Plates: The first-formed plates on the dorsal side of the disk; in ophiuroids, these are the central and five radial plates; in adults, they may form a rosette of scales near the center of the disk, or they may be separated by numerous secondarily developed scales.
Radial: In a direction toward the central axis of an arm or ambulacrum; a part of the body near an arm or ambulacrum.
Radial Shields: Pairs of plates on the dorsal surface of the ophiuroid disk, which lie near the base of each arm; usually relatively large and conspicuous, but may be hidden by granules or superficial scales.
Rods: One of several types of microscopic skeletal ossicles in holothuroids; commonly found as supporting structures in tentacles or tube feet.
Scales: One of several types of skeletal elements in echinoderms; flat, thin structures that are overlapping, tessellate, or haphazardly arrayed.
Sole: In some holothuroids, the flattened ventral part of the body, either covered with or surrounded by tube feet.
Spines: One of several skeletal elements in echinoderms; movable, articulating structures that are long, slender and attenuated.
Teeth: In ophiuroids, small plates or spines attached to the dental plate on the inner edge of the jaw, a series of them extending into the mouth; in echinoids, the five hard, sharp, and movable ossicles incorporated in Aristotle’s lantern; the term also refers to five movable ossicles that surround the anus of some holothuroids.
Tentacle Scales: Small, movable spines or scales, associated with ophiuroid tube feet, which are attached to the ventral arm plate and/or lateral arm plate; may cover the tentacle pores and protect the retracted tube feet.
Tentacles: In holothuroids, feeding structures in the form of highly modified tube feet arranged in a ring around the mouth.
Terminal Disk: Round portion on the end of the tube foot in many echinoderms; usually employed for attachment to substrates.
Tube Feet: Fluid-filled, fingerlike extensions of the water vascular system that protrude through the openings in the skeleton or between skeletal elements; muscles and nerves in the shaft of the tube feet control their movements; glands, and sometimes a muscular sucker, at the tip function in adhesion; specialized tube feet are used for locomotion, feeding, burrowing, respiration, and a combination of functions.
Ventral: In echinoderms, this term is variously applied; in asteroids, echinoids and ophiuroids, it is the surface of the body that carries the mouth; this surface is in contact with the substrate; in holothuroids, with mouth and anus at opposite ends of a cylindrical body, the ventral surface is lowermost, in contact with the substrate; in crinoids, the ventral surface carries the mouth and is functionally the uppermost surface.