Megabalanus coccopoma ( Darwin, 1854 )

Shahdadi, Adnan, Sari, Alireza & Naderloo, Reza, 2014, A checklist of the barnacles (Crustacea: Cirripedia: Thoracica) of the Persian Gulf and Gulf of Oman with nine new records, Zootaxa 3784 (3), pp. 201-223 : 217

Megabalanus coccopoma ( Darwin, 1854)

( Figs 11a–-d , j, k, 12a–l)

Material examined. ZUTC-cirri 1179, 1180, 1181, 1182, 1183, 1184.

Persian Gulf. First record from the Persian Gulf.

Gulf of Oman. First record from the Gulf of Oman.

General distribution and habitat. Indo-Pacific and Atlantic Oceans; fouling species of various substrata, intertidal to sublittoral. ( Henry & McLaughlin 1986; Yamaguchi et al. 2009; Newman & Ross 1976; present study).

Descriptive features and remarks. The present specimens show some intraspecific morphological variations as well as some age-dependent variations ( Figs 12 a–l). Younger specimens: shell globo-conic, smooth or ribbed, orifice rhomboido-oval (fig. 11j); shell pink or red; tergum and scutum ( Figs 11a–d ) violet to white or yellow. Scutum with tergal segment wide. Tergum with distance between spur and baso-scutal angle equal to or more than spur width, basal margin sometimes straight on both sides. Older specimens: shell cylindrical, orifice diameter wider than half basal diameter (fig. 11k; see arrow). Largest specimen, ZUTC-cirri 1181, with basal diameter 46.9 mm, height 38.64 mm, orifice diameter 30.0 mm. Scutum with tergal segment narrow; during growth, rough crenulated ridges becoming blunt, closer together with longitudinal striae more obvious. Scutum with ratio of length of articular ridge to length the tergal margin becoming smaller. Tergum with ratio of length of articular ridge to length the scutal margin also becoming smaller ( Figs 8 a–l).

The specimens were collected from Dayyer (27° 49'N, 51° 55'E), Bandar-Lengeh (27° 02'N, 53° 16'E), Jask (25° 41'N, 57° 53'E) and Chabahar (25° 16'N, 60° 44'E) ( Fig. 1 ) from various substrata, such as rocks, jetties, floating objects, ropes and crab carapaces.

Figures

FIGURE 1. Map of sampling sites of the species recorded in the Persian Gulf and the Gulf of Oman.

FIGURE 8. Amphibalanus subalbidus (Henry, 1973), ZUTC-Cirri 1187 from Arvand River; a. tergum, external view; b. tergum, internal view; c. scutum, internal view; d. scutum, external view; e. sheath with vesicles; f. segments of cirrus IV; g. labrum, h. specimens on stone.

FIGURE 12. Megabalanus coccopoma (Darwin, 1854) age and size dependent variations in tergum and scutum; a-d. ZUTCcirri 1179, with basal (rostro-carinal) diameter 16 mm; e-h. ZUTC-cirri 1181, with basal (rostro-carinal) diameter 30 mm; i-l. ZUTC-cirri 1181, with basal (rostro-carinal) diameter 46 mm.

FIGURE 11. a – d: Megabalanus coccopoma (Darwin, 1854); a. scutum internal, view; b. scutum, external view; c. tergum, internal view; d. tergum, external view. e-h: Megabalanus occator (Darwin, 1854); e. scutum, internal view; f. scutum, external view; g. tergum, internal view; h. tergum, external view; i. Megabalanus occator, ZUTC-Cirri 1185, Chabahar, Gulf of Oman; j. Megabalanus coccopoma, ZUTC-cirri 1179, Chabahar, Gulf of Oman; k. Megabalanus coccopoma, ZUTC-cirri 1181, Chabahar, Gulf of Oman.