Luidia superba
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| Luidia superba | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Paxillosida |
| Family: | Luidiidae |
| Genus: | Luidia |
| Species: | L. superba |
| Binomial name | |
| Luidia superba A. H. Clark, 1917 [1] | |
Luidia superba is a tropical species of starfish in the family Luidiidae. A single specimen was found off the Pacific coast of Colombia in 1888; the species has since been found in the Galapagos Islands. It is endemic to this area and has not been recorded elsewhere.
A typical Luidia superba has five long, tapering arms with pointed tips. The holotype, the first specimen to be observed and described, had six arms, which was unfortunate as that led to the belief for many years that the normal number of limbs was six.[2] As in other members of the genus, the upper surface of the disc and the arms is covered with paxillae, pillar-like spines with truncated ends. On the underside there are multiple rows of tube feet running down each arm.[3] The colour is greenish-brown above and creamy yellow beneath, the tube feet being tipped with orange.[4]
Luidia superba is probably the largest five-armed starfish in the world.[2] The largest specimen from Tagus Cove in the Galapagos Islands had a radius, measured from the centre of the disc to the tip of the arms, of 41.5 centimetres (16.3 in). Its other dimensions were a disc radius of 4.5 centimetres (1.8 in), a maximum arm width of 6 centimetres (2.4 in) and a longest spine of 1.5 centimetres (0.59 in).[2] By comparison, a specimen of the ten-armed Luidia magnifica from Hawaii had a radius of 38 centimetres (15 in) and the nine-armed Luidia savignyi at 37 centimetres (15 in) was the largest known starfish at the time at which it was measured.[2] The site at Tagus Cove is species rich because of the upwelling of the nutrient-laden, cool water Equatorial Undercurrent nearby, providing an optimum environment for growth which may encourage gigantism.[2]