|Distribution||Early Pliocene to Recent, Tropical and subtropical Pacific coast of the Americas (Mexico to Colombia).|
|Type||Mellita longifissa Michelin, 1858, by original designation.|
|Classification and/or Status||Clypeasteroida; Scutellina; Scutelliformes; Scutellidea; Mellitidae.|
|Remarks||It differs from Leodia in having no lunule in the anterior ambulacrum (see Mooi & Peterson 2000 for discussion) and from Mellita in having bidentate pedicellariae with simple valves and small peripheral teeth present along the edge of the blade (no enlarged terminal teeth) and food grooves passing close to the ambulacral lunule edges (widely spaced in Mellita). While highly similar to Mellita in morphology, the two genera form two very distinct groups in genetical analyses (based both on mtDNA and nDNA, see Coppard et al. 2013).
See Harold & Telford (1990) for an excellent review of the genus Mellita together with a key to the species.
Coppard, S. E., Zigler, K. S. & Lessios, H. A. 2013. Phylogeography of the sand dollar genus Mellita: Cryptic speciation along the coasts of the Americas. Molecular Phylogenetics and Evolution, 69, 1033-1042.
Harold, A. S. & Telford, M. 1990. Systematics, phylogeny and biogeography of the genus Mellita (Echinoidea: Clypeasteroida). Journal of Natural History 24, 987-1026. -