Holotype specimen is from the South Pacific, Austral Ridge, Rapa I., Haurei Bay, off Point Turagainuu,
under basalt boulders, depth of 1–2 m, collected by D.M. Devaney,Feb 1971, BPBM W3507.
From O'Loughlin (2002).
Meridiastra rapa is a small, cryptically colored, tropical sea star from the South Pacific.Like many members of the family Asterinidae (the cushion stars), its short legs are mostly webbed, giving it a pentagonal shape, and it has a flat ventral surface adapted to clinging to hard rock surfaces. It is the smallest of the Meridiastra species, measuring about 1.1cm (0.4 inches) across.Its dorsal surface is a mottled pink and red coloration (O’Loughlin 2002).
This sea star lives on and under rocks in shallow intertidal waters between 1-2 m (3-6 feet) deep (O’loughlin 2002). Its name refers to the location where it was first found, Rapa Island (its type location); it is also reported from other parts of French Polynesia, including the Society Islands (O’Loughlin 2002; Mah 2015; IDigBio Portal 2016).
Meridiastra rapa and two of its three congenitors (M. nigranota and M. fissura) were all described as new species between 1997 and 2003.They were placed, along with a species from genus Asterina into the newly erected genus Meridiastra.More recent molecular and morphological comparisons and analysis suggest that the genus Meridiastra may include other Asterina species; further research may revise the nomenclature in these genera (Waters et al. 2004; O’Loughlin and Waters 2004).
