A THORNY ECHINODERM

In my personal collection of marine invertebrates, I have a small echinoderm typically referred to as a  "star fish." [Of course, it is neither a star, nor a fish!] 

This echinoderm, which is somewhat unusual in that it is very  thorny.  is Amphiaster insignis Verrrill. This is the only species known of this genus. Its “arms” are very wide near the central disc area. In life, the body and arms are uniformly colored red-orange to red brown. The specimen shown here has been bleached by exposure to the sun. 

Amphiaster insignis is known from the central and lower part of the Gulf of California, to at least as far south as Panama (Brusca, 1980, p. 405, fig. 26.10). It is a common species.

   Classification

Kingdom Animalia

Phylum Echinodermata

Class Asteroidea

Order Oreasterida

Family Goniasteridae

Genus Amphiaster

Type species: A. insignis

Figure 1. Dorsal view of starfish, specimen diameter 60 mm, thickness 12 mm.

Figure 2. Ventral view of specimen shown above.

Reference

Brusca, R.C. 1980. Common intertidal invertebrates of the Gulf of California, 2^nd ed., 513 pp.