Culcita schmideliana

Lore & Background

Culcita schmideliana has a leathery surface and an inflated appearance, with a very convex aboral surface and flat base. The aboral surface is scattered with small conical spines that supposedly never enter the papular zones, while the oral surface has small granulations and large conical tubercles, those nearest the ambulacral grooves and margin being ovate in cross section and the largest. Its color varies but often features a greyish background with small pink patches mostly adjacent to black tubercles, and the madreporite is usually orangeish.

This starfish hosts several commensal animals: a carapid fish typically lives in its stomach, the polychaete worm Gastrolepidia clavigera crawls over its surface, and the tiny shrimp Periclimenes soror hides almost invisibly on its aboral surface. It is native to the tropical western Indo-Pacific, ranging from Madagascar and the Red Sea to Australia, and is found in lagoon areas and inner reef flats with seagrasses and algae at depths down to about 92 m.

Culcita schmideliana feeds mainly on epibenthic film of organic detritus and micro-organisms growing on algae and seagrasses. It also browses on the sponge Gellius cymiformis, associated with the symbiotic alga Ceratodictyon spongiosum, and on the living tissues and polyps of stony corals Galaxea and Goniopora and the soft coral Xenia. In this grazing behavior it resembles the better known cushion star Culcita novaeguineae.

Reader's Guide

Culcita schmideliana is significant as a species of pin-cushion star that illustrates the ecological role of cushion stars in tropical Indo-Pacific reef systems. Its feeding habits, which include grazing on epibenthic film, sponges, and corals, mirror those of the better known Culcita novaeguineae, highlighting a shared niche among cushion stars. The species is notable for its commensal relationships, hosting a carapid fish in its stomach, a polychaete worm on its surface, and a shrimp on its aboral surface, demonstrating a complex micro-ecosystem. Its rarity in the hobby aquarist trade underscores its specialized habitat requirements. The starfish's variable coloration, with greyish background and pink patches near black tubercles, and its orangeish madreporite, contribute to its distinct appearance. Its distribution across a wide Indo-Pacific range, from East Africa to Australia, and its occurrence in lagoon and reef flat habitats down to 92 meters, indicate its adaptability to various shallow marine environments. The species' leathery, inflated, pentagonal form and the presence of conical spines and tubercles are key morphological traits. Overall, Culcita schmideliana serves as an example of the biodiversity and symbiotic interactions within coral reef ecosystems.

Did You Know?

• A carapid fish is usually found living in its stomach.
• It browses on the sponge Gellius cymiformis and the corals Galaxea, Goniopora, and Xenia.