Luidia
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 fringed with spines. Their upper surfaces are covered with paxillae, pillar-like spines with flattened summits covered with minute spinules. The upper marginal plates are replaced by paxillae, but the lower marginal plates are large and covered with paxillae. The tube feet do not have suckers, but have two swollen regions. A mouth, oesophagus, and cardiac stomach are seen, but no pyloric stomach or anus is present. The gonads are underneath the sides of each arm.The early larval stages of starfish are known as bipinnarial larvae, and members of this genus do not continue their development after this stage into a brachiolar stage before undergoing metamorphosis. However, they are capable of larval cloning, with asexual reproduction taking place while they are larvae. This has been shown to take place both in the field and in laboratory cultures and has been studied by molecular analysis of sequences of mitochondrial tRNA to identify the taxa involved.
Species
, the following species are recognized by the World Register of Marine Species:- Luidia alternata – banded sea star
- Luidia amurensis
- Luidia armata
- Luidia asthenosoma
- Luidia atlantidea
- Luidia australiae
- Luidia avicularia
- Luidia barbadensis
- Luidia bellonae
- Luidia changi
- Luidia ciliaris – seven-armed star
- Luidia clathrata – slender-armed starfish, gray sea star, lined sea star
- Luidia columbia
- Luidia denudata
- Luidia difficilis
- Luidia ferruginea
- Luidia foliolata – spiny mudstar, leafy flat star, sand star
- Luidia gymnochora
- Luidia hardwicki
- Luidia herdmani
- Luidia heterozona
- Luidia hexactis
- Luidia inarmata
- Luidia integra
- Luidia iwakiensis
- Luidia latiradiata
- Luidia lawrencei
- Luidia longispina
- Luidia ludwigi
- Luidia maculata
- Luidia magellanica
- Luidia magnifica – magnificent star
- Luidia mauritiensis
- Luidia neozelanica
- Luidia orientalis
- Luidia patriae
- Luidia penangensis
- Luidia phragma
- Luidia porteri
- Luidia prionota
- Luidia quinaria – spiny sand sea star
- Luidia sagamina
- Luidia sarsii
- Luidia savignyi
- Luidia senegalensis – nine-armed sea star
- Luidia sibogae
- Luidia superba – giant sea star
- Luidia tessellata
- ''Luidia yesoensis''