Amphibalanus amphitrite (Darwin, 1854)

(Figs 7 a–n)

Material examined. ZUTC-cirri 1101, 1102, 1103, 1104, 1105, 1106, 1107, 1108, 1109, 1110, 1111, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1120, 1121.

Persian Gulf. Nilsson-Cantell (1938) as Balanus amphitrite hawaiiensis from an unknown locality; Stubbings (1961) as B. amphitrite var. communis, and B. amphitrite var. hawaiiensis, from Kuwait; Utinomi (1969) as B. amphitrite from Hormoz Island; Jones (1986) as B. amphitrite var. communis from Kuwait (Fig. 1); present study.

Gulf of Oman. Utinomi (1969) as Balanus amphitrite from an unknown locality; present study.

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

Descriptive features and remarks. Specimens examined show some morphological variations. Most specimens with conic shells (Figs 7 m, n) and typical tergum and scutum (Figs 7 a–d). In dense clusters, shell cylindrical, but specimens within oyster populations with depressed shell, with tergum and scutum long, narrow (Figs 7 e–h).

Exposed and eroded shells with no purple stripes externally. Tergum with spur short, round, and carinal margin rounded; scutum with articular furrow deep (Figs 7 i–l).

Largest specimen (ZUTC-cirri 1110) with basal diameter 27.2 mm, height 11.2 mm.

This species is common in various localities along the Iranian coast, occurring in habitats with salinities ranging from 5 ppt in the Bahmanshir River, together with A. subalbidus (Fig. 1) to 43 ppt. Specimens also attach to various substrata, such as mangrove trunks and pneumatophores, human-made structures, intertidal rocks, mollusc shells, crab carapaces, ship and vessel hulls and floating objects.