Balanus trigonus Darwin, 1854

(Figs 10 a–g)

Material examined. ZUTC-cirri 1167, 1168, 1169, 1170, 1171, 1172, 1173.

Persian Gulf. Nilsson-Cantell (1938) from an unknown locality; Utinomi (1969) from Larak Island in Iran (Fig. 1); present study.

Gulf of Oman. Nilsson-Cantell (1938) from an unknown locality; present study.

General distribution and habitat. Cosmopolitan, ranging from tropical to temperate seas; fouling species on various substrata, littoral to sublittoral (Jones et al. 2000; present study).

Descriptive features and remarks. Shell conic, with small triangle orifice. External surface of parietes ribbed, ribs white on red or pink field (Figs 10 e-g). Scutum externally with longitudinal rows of holes (Figs 10 b); tergum with spur wide (Figs 10 c, d). Largest specimen (ZUTC-cirri 1171) with basal diameter 17.56 mm, height 9.0 mm.

The specimens were collected from various substrata such as littoral rocks, mollusc shells and floating objects at Nayband (27° 23'N, 52° 39'E), Parsian (27° 02'N, 53° 16'E), Jask (25° 41'N, 57° 53' E), Chabahar (25° 19'N, 60° 37'E) and Gwatr (25° 08'N, 61° 27'E) (Fig. 1).