Luidia alternata can be found from North Carolina down to Argentina. Although they concentrate on the coasts of Mississippi, Texas, and Mexico, L. alternata are also seen in the Caribbean and off of Florida's coast.

Biogeographic Regions: atlantic ocean (Native )

Caribbean Sea, Colombia, Cuba, Dominican Republic, Gulf of Mexico, Honduras, Mexico, Panama, Puerto Rico, Venezuela

Luida alternata usually reaches 20 cm from arm to arm but some may increase to a diameter of 40 cm. Its dorsal side is white or cream-colored with bands of dark green, purple, black or brown scattered on it. Its ventral surface is yellow with bright orange tube feet. They have five straplike arms fringed with slender spines. They appear fragile with the rows of paxillae irregularly arranged. The paxillae near the arm margins are larger than the midline and they hold a single long, pointed erect spine surrounded by small spinelets.

These sea stars occur in sandy and muddy sediment in 3-50 meters of water.

Aquatic Biomes: benthic

Depth range based on 147 specimens in 3 taxa.
Water temperature and chemistry ranges based on 92 samples.

Environmental ranges
  Depth range (m): 5.8 - 1500
  Temperature range (°C): 19.415 - 27.880
  Nitrate (umol/L): 0.325 - 8.870
  Salinity (PPS): 35.682 - 36.886
  Oxygen (ml/l): 2.616 - 4.992
  Phosphate (umol/l): 0.055 - 0.707
  Silicate (umol/l): 0.756 - 3.912

Graphical representation

Depth range (m): 5.8 - 1500

Temperature range (°C): 19.415 - 27.880

Nitrate (umol/L): 0.325 - 8.870

Salinity (PPS): 35.682 - 36.886

Oxygen (ml/l): 2.616 - 4.992

Phosphate (umol/l): 0.055 - 0.707

Silicate (umol/l): 0.756 - 3.912
 
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L. alternata usually preys on other echinoderms like brittle stars, but on occasion they consume dead bait thrown overboard by fishermen. Since it is a common inhabitant of scallop beds off the Carolina coast, it usually preys on small individuals of the sea star species Astropecten articulatus. Because their tube feet lack the suckers needed to open bivalves, they swallow their prey whole, then regurgitate the undigestable portions.

The ovaries of a female are pale salmon and contains egg cells about 1.9 mm in diameter. Female stars release their eggs into the water when they detects the presence of sperm, and vice versa for males. The triggers to begin the process are not known. The eggs that are fertillized develop into a free-swimming bilaterally symmetrical larvae called a bipinnaria. After about a month the 2mm long bipinnaria settles to the bottom and metamorphoses into the radially symmetric adult form.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

US Federal List: no special status

CITES: no special status

Since this species feeds on other seastars, it may be beneficial to shellfish fisheries because it eats other sea stars, some of which eat shellfish. Also, L. alternata is often used for eductional study.