Samus anonymus Gray, 1867

(Figure 9)

Synonymy and references. Samus anonymus Gray, 1867: van Soest and Hooper (2002): 100, fig.1.

Material. USNM 1228911, Columbus Cay cave, 18–25 m; G. Hendler, I. Macintyre, P. Kier, T. Rath & C. Clark col. 21 Mar 1979.

External morphology. Excavating and filling crevices in and between vacated serpulid worm tubes (“pseudostalactites”). Color in life yellowish tan.

Skeleton structure. Megascleres (triaenes) and microscleres (sigmaspires) dispersed throughout the tissue, without organization. Abundance of foreign spicules accumulated from the sediment.

Spicules. The megascleres are essentially variants of short-shafted amphitriaenes, some symmetrical, others asymmetrical in branching patterns (dichotomous or trichotromous); smaller (possibly developing) spicules are microspined: 44–117 x 35 –103 (71 x 65) Μm; sigmaspires with few but long, hook-like spines: 9–13 (11) Μm. Ecology. Common but inconspicuous in many cryptic habitats, to 25 m or more.

Distribution. First described from off Brazil, the species is reported worldwide, primarily from tropical and subtropical locations. Previos reports of this species do not mention microspined amphitriaenes, but the spination may have been overlooked or can be attributed to developmental stages of these spicules.