Taxonomic remarks of the genus Luidia

Luidia alternata alternata differs from its Atlantic congeners by having a conspicuous (~ 1.5 mm) spine in the center of most paxillae from the abactinal region (vs. central spine[s] not as conspicuous [<1 mm]).

Luidia clathrata differs from L. lawrencei by having two subambulacral spines (vs. three subambulacral spines in large specimens) and paxillae of central disc circular and dense (vs. paxillae of central disc squarish and not dense), from L. patriae by having unequal paxillar spinelets (vs. spinelets of same size), from L. senegalensis by having five arms (vs. nine arms), and from the remaining Atlantic species (i.e. L. alternata, L. barbadensis, L. heterozona, L. ludwigi, L. sagamina, L. ciliaris, L. sarsi, and L. atlantidea) by not having pedicellariae (vs. pedicellariae present).

Luidia senegalensis differs from its Atlantic congeners by having nine (rarely 7–8) arms and a larger actinal interradial area. Luidia senegalensis also differs from L. ciliaris by having four ambulacral spines (vs. two).