Grey Sea Star, Luidia clathrata

The grey sea star (Luidia clathrata), also known as the slender-armed starfish or the lined sea star, is a species that can be found in westerns areas of the Atlantic Ocean. Its range extends from Brazil in the south to Virginia in the United States and includes the Gulf of Mexico and Caribbean Sea. It prefers to reside in muddy or sandy areas along the coastline, at depths of up to 131 feet, although it can sometimes be found in deeper waters. This species was first discovered by Thomas Pennant in 1777, but was given the name Asterias clathrata, but was later named Luidia clathrata by Thomas Say. After some debate over this name, which turned out to be invalid, the International Code of Zoological Nomenclature renamed this sea star Asterias clathrata. In 1982, the ICZN, prompted by A. M. Clark, renamed the grey sea star Luidia clathrata.

The grey sea star can reach a diameter of up to twelve inches. This size comes not from the body, or disc, but from measuring around the points of its slender arms. It is typically light brown or grey in color, but it can appear to have pink undertones. The upper side of the arms and disc contain spines that resemble pillars known as paxillae and rows of hardened plates known as ossicles. The underside of the sea star, which is pale in color, is also covered with plates, which hold a number of paxillae. Although this species does have tube feet along the underside in longitudinal patterns, these feet do not have suckers, instead holding two enlarged areas. As is typical to sea stars, this species holds a mouth in the center of the disc and reproductive organs on the sides of each arm.

The grey seat star spawns once a year, releasing larvae into the water column where they remain for about one month. After this period, the larvae are developed enough to sink to the sea floor after which time they will undergo metamorphosis and grow into young seat stars. This species is a forager and a predator, consuming species like Mulinia lateralis if it is abundant. When preferred species are not available, the sea star will eat sediment, sifting the nutrients and particles out by using the spines in its mouth. Its diet consists of nematodes, detritus, small crustaceans, bivalve and gastropod molluscs, ostracods, and foraminiferans. The grey sea star will spend the daylight hours buried in the sediment, and may turn its mouth inside out to consume particles from its hiding spot. If a predator takes a limb from this species, it is able regenerate the lost limb.

Image Caption: Lined Sea Star at St. Lucie County Marine Center in Fort Pierce, St. Lucie County, Florida, U.S.A. Credit: Hans Hillewaert/Wikipedia (CC BY-SA 3.0)