''Luidia clathrata'' is a tropical

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...

in the family

Luidiidae ''Luidia'' is a genus of starfish in the family Luidiidae in which it is the only genus. Species of the family have a cosmopolitan distribution. Characteristics Members of the genus are characterised by having long arms with pointed tips frin ...

. It is variously known as the slender-armed starfish, the gray sea star, or the lined sea star. It is found in the western Atlantic Ocean.

Description

''Luidia clathrata'' is a large, flattish starfish, sometimes growing to a diameter of . It has a relatively small disc and five slender arms, which are two or three times the diameter of the disc. The upper surface of the disc and arms is clad in longitudinal rows of

calcified Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...

plates called ossicles, and in paxillae, pillar-like spines with flattened summits covered with minute spinules. No plates are found along the margins of the arms, these being replaced by paxillae, but on the underside, the marginal plates are large and themselves covered with paxillae. The

tube feet Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...

, found in longitudinal rows on the underside, do not have suckers, but have two swollen regions. A mouth is in the centre of the underside, with an oesophagus and cardiac stomach which can be everted. The

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

s are underneath the sides of each arm. Its colour is usually grey or light brown, but can be tinged with pink. The central row of plates on the upper side of the arms is usually dark grey or black. The underside of the starfish is a paler colour.''Luidia clathrata'' Gray sea star
Smithsonian Marine Station at Fort Pierce. Retrieved 2012-01-30.

Distribution and habitat

''L. clathrata'' is found around the coastlines of the western Atlantic Ocean, from

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

south to

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

, and the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. It is usually on sandy or muddy sea beds down to a depth around , although it is occasionally found in deeper waters down to .

Biology and ecology

When ''L. clathrata'' loses part or all of an arm through

predation Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

, it can regenerate the limb. The damaged area is sealed off, and a new small arm-tip appears within a week. Subsequent development is at the rate of about a month, although this slows down when regeneration is nearly complete. A study on the regenerative capacity of ''L. clathrata'' found that increased

ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxid ...

, as is likely to happen under

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

, had no significant effect on the starfish's ability to regenerate its limbs. ''L. clathrata'' is both a predator and a forager. It selectively feeds on the "coot clam", ''

Mulinia lateralis ''Mulinia lateralis'', the dwarf surf clam or coot clam, is a species of small saltwater clam, a bivalve mollusc in the family Mactridae. It occurs in the western Atlantic Ocean and the Caribbean Sea. Description ''Mulinia lateralis'' has a some ...

'', when it is abundant, using chemoreceptors to help it find its prey. The coot clam is the preferred food of ''L. clathrata'' in Tampa Bay in Florida. At other times, it feeds by ingesting sediment and straining the material through spines around its mouth, extracting food particles in the process. Its diet includes both

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

and

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

molluscs,

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...

ns,

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

s, small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s, and

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

. It is photosensitive and mostly spends the daylight hours buried in the sediment. While buried, it sometimes everts its stomach to ingest detritus. ''L. clathrata'' spawns annually. The larvae pass through a

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic bipinnaria stage, which lasts about a month before settling on the seabed, undergoing

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

, and becoming juvenile starfish.

References

{{Taxonbar, from=Q2777443 Luidia Fauna of the Atlantic Ocean Animals described in 1825 Taxa named by Thomas Say