Brittle stars (Echinodermata: Ophiuroidea) are a common component of marine communities and often make up a significant portion of the biomass. Identification, however, can be problematic, particularly in the small fissiparous species. Fissiparity, asexual reproduction in which an individual divides in two and regenerates missing parts, occurs in 34 of the 2,000 species of brittle star (Emson & Wilkie 1980). One of these is Ophiactis simplex, an eastern Pacific species, with distribution from the Channel Islands to Panama and the Galapagos Islands (Neilsen 1932; Lonhart & Tupen 2001). Like other fissiparous brittle stars most specimens have six arms and are asymmetrical, with three long arms and three shorter arms. However, individuals with five and seven arms are not uncommon; the author has collected one with nine arms. One of the distinguishing characteristics of this species is the red tube feet. The red color is due to the presence of hemoglobin containing coelomocytes (RBCs) present in the water vascular system (Christensen 1999).

In late May 2001, five specimens of O. simplex were collected in a tide trap located on the research pier at the University of Texas Marine Science Institute, in Port Aransas, Texas. The specimens were found on algae caught in the net and were very small (disc diameter < 2 mm). Later that week approximately 200 specimens were collected from algae and other fouling material scraped from the rocks of the south jetty at Port Aransas. This represents a first report of this species along the Texas coast. Official counts were not made at this time. Voucher specimens were sent to Dr. Gordon Hendler at Museum of Natural History of Los Angeles for positive identification. Several subsequent collections have been made from the south jetty to determine habitat preference and population structure.

In January 2002, various species of algae, sponge, hydroid and tunicate colonies were scraped from the south jetty during an extremely low tide. Brittle stars were removed from the substrate, counted, and the volume...