Shell small to medium-sized, adults reaching a height of almost 55 mm; relatively thin-shelled but solid; as tall as wide or slightly taller than wide (h/w=l.0-1.1). Apex white. Teleoconch of about 3 to 4 whorls, mostly rounded, sometimes slightly angulated with a distinct subsutural ramp; sculpture consisting of numerous close-set spiral cords, three of them on the body whorl bearing weak to strong nodules or fluted scales; between these cords there are single rows of beads or small nodules. Columella smooth and evenly rounded with a heavy columellar callus; aperture round; lower part of lip projecting downward; umbilicus closed. Basic color whitish-gray, maculated with large patches or flames of beige, greenish, orange-brown or reddish. Some specimens show distinct spiral color bands below the shoulder. Aperture and columella white, inside of aperture nacreous. Operculum thick, round and smooth; white with a small to very large tan to purplish-brown marking. The inshore form of Turbo (Marmarostoma) castanea has an operculum with a noticeable subcentral pit.

Shell turbinate, with five to six and a half whorls which are generally rounded, imperforate, and having a found aperture; the sculpture consisting of revolving, nodulous ridges everywhere closely set; two of these on the upper whorls and three on the body whorl are stronger than the rest, and often rise into knobs or vaulted scales, making the shell somewhat angulate. There is often a row of knobs just below the suture; columella thickened and rounded, the base of the shell projecting a little. The color pattern is much diversified, the ground being gray, orange, orange brown or greenish variously blotched with whitish. The operculum is chestnut colored within.
Height, 30; diameter, 23 mm.
Hoqueron Bay; Ponce Reefs; Puerto Real; Fajardo; Mayaguez; Catena; San Juan; Gnunica, Porto Rico. An abundant, widely distributed form.

Turbo castanea Gmelin, 1791 Chestnut Turban
Distribution: North Carolina to Florida, Texas; West Indies; Brazil. Size: 25 to 38 mm.
Description: Color variable grayish to orangish-brown, splotched with white; shape turbinate; spire short; beaded spiral cords of different strengths on teleoconch whorls; whorls can be beaded, knobby, or scaly; strong sculpture usually seen just below the suture with strongest sculpture occurring at the periphery and shoulder of teleoconch whorls; on base next to columella, beaded sculpture becomes elongate and swollen; aperture round and white; anomphalous.
Habitat: In Texas found on offshore banks, coral reefs, and platforms at depths of about 126 m (420 ft). Depth range 0 to 141 m (465 ft). Remarks: Throughout its range, usually found in grass beds in shallow water; but in Texas found in deeper water. See Lyons (1988); Redfern (2001).

The only other Caribbean Turbo which can be confused with less tuberculate forms of Turbo (Marmarostoma) castanea is Turbo (Taeniaturbo) cailletii, which can be easily recognized by the presence of a distinct umbilicus.

North Carolina to Florida, Texas and the West Indies, eastern Colombia through Venezuela and the Guyanas to northeastern Brazil.