Tetraclita squamosa ( Bruguiere , 1789)

Pochai, Ashitapol, Kingtong, Sutin, Sukparangsi, Woranop & Khachonpisitsak, Salinee, 2017, The diversity of acorn barnacles (Cirripedia, Balanomorpha) across Thailand's coasts: The Andaman Sea and the Gulf of Thailand, Zoosystematics and Evolution 93 (1), pp. 13-34 : 20

Tetraclita squamosa ( Bruguiere, 1789) Figure 8 ; Suppl. material 3; Tables 2, 3

Balanus squamosa Bruguiére, 1789: 170.

Lepas porosa Gmelin, 1791: 3212.

Tetraclita porosa var. viridis : Darwin 1854: 329; Borradaile 1900: 799; Gruvel 1905: 228; Krüger 1911: 61, pl. 4, fig. 41b; Hoek 1913: 254;

Tetraclita squamosa : Stebbing 1910: 570; Barnard 1924: 90; Oliveira 1941: 6.

Tetraclita squamosa squamosa : Pilsbry 1916: 251; Kolosváry 1943: 96; Henry 1957: 33; Stubbings 1967: 294; Newman and Ross 1976: 48; Ren and Liu 1979: 339, pl. 1, figs. 1-11.

Tetraclita squamosa forma viridis : Broch 1922: 337; 1931: 116.

Tetraclita porosa perfecta Nilsson-Cantell, 1921: 364.

Tetraclita squamosa : Yamaguchi 1987: 344; Chan 2001: 625, fig. 8; Chan et al. 2007b: 82, fig. 4.

Non-type material examined.

Gulf of Thailand: 2 specimens, Nakhon Si Thammarat province, Sichon district, Hin Ngam beach, 04.VII.2015, A. Pochai (BUU16.TC.TSS01-02) .

Description.

Peduncle absent; base membranous; shell green mixed with brownish grey, shell with 4 plates (1 carina, 2 latus, 1 rostrum); parietes conical, plate fused, inseparable, 8 rows of parietal tubes (parietes multiple tubiferous), external surface with longitudinal lines from base to apex, internal surface of parietes smooth and white with purplish grey striations close to aperture, External surface of operculum brownish grey, internal surface of operculum purplish grey. Scutum larger than tergum, scutum triangular, long articular ridge-basal margin, external surface of scutum with horizontal striations, occludent margin of scutum with very shallow teeth; tergum higher than wide, basi-scutal margin 158-160°, tergum apex obviously beaked, tergum with spur long and sharp, spur angle 25°. Mandible with 4 big teeth, 1st tooth with three small spines, lower margin pectinate; maxillule notched, two large setae above notch, 11 big setae below notch and some smaller setae at the edge; labrum with 4 large teeth on each side; cirri I possessing bidenate serrulate setae.

Distribution.

Tetraclita squamosa is widespread in tropical and subtropical waters from West Africa, the Indo-Pacific, the Indian Ocean, Australia, Indonesia and Singapore ( Newman and Ross 1976; Ren and Liu 1979; Jones et al. 2000; Chan et al. 2007b). Its distributions in Thailand were previously recorded in two places: the Andaman Islands and the Gulf of Siam (recently called the Gulf of Thailand) ( Jones 2000). In this present study, Tetraclita squamosa has restricted areas of distribution and it was found specifically at Hin Ngam beach, the Gulf of Thailand coast. Regarding vertical zonation, Tetraclita squamosa found in Thailand occurs on the mid shore.

Remark.

As described in Chan et al. 2007a, b, Tetraclita squamosa (southern China) has unique tergum characteristics including tergum with beak and long spur, and scutum with long articular ridge-basal margin. Our specimens from Hin Ngam beach have all of these characteristics; hence, it is more fitted into Tetraclita squamosa (Southern China) rather than Tetraclita squamosa (Singapore), which is reassigned as Tetraclita singaporensis .

Figures

Figure 8. Tetraclita squamosa collected from Hin Ngam beach, Nakhon Si Thammarat (BUU 16. TC. TS 01). A. Dorsal and ventral view of external shell, B. External (left panel) and internal (right panel) view of tergum (upper panel) and scutum (lower panel), C. External (upper panel) and internal (lower panel) view of shell plates, D. Close up on external surface of shell, E-H. Light microscopy on mouthparts, E. Labrum, E. Close up on the teeth of the labrum, G. Mandible, G. Close up on the pectinated lower margin of mandible. E-H. Scale bars in µm. Abbreviations: c, carina; l, latus; r, rostrum.