Megabalanus tintinnabulum (Linnaeus, 1758)

Trivedi, Jigneshkumar N., Doshi, Mahima, Patel, Krupal J. & Chan, Benny K. K., 2021, Diversity of intertidal, epibiotic, and fouling barnacles (Cirripedia, Thoracica) from Gujarat, northwest India, ZooKeys 1026, pp. 143-178 : 143

Megabalanus tintinnabulum (Linnaeus, 1758) Figures 2D, E , 7

Examined material.

Five specimens (BD: 10.57-24.26 mm), LFSc.ZRC-182, Veraval, Gir Somnath district (20°54.60'N, 70°21.13'E), 18 November 2019, Gujarat, India, rocky shore, leg. K. Patel.

Diagnosis

(modified from Chan et al. 2009). Shell cylindrical to conical, colouration variable, mostly with rosy pink longitudinal stripes, surface smooth (Fig. 2D ). Scutum triangular, with prominent transverse growth ridges, external surface bearing horizontal striations, inner surface with conspicuous articular ridges, articular ridges broad (Fig. 2E ). Tergum broad and triangular, spur long, narrow, prominent. External surface with median furrow (Fig. 2E ). Maxilla bilobed with setae on all margins (Fig. 7A ). Maxillule not notched, cutting edge straight (Fig. 7B ). Mandible with 5 teeth excluding inferior angle, 1st tooth largest, sharply pointed, inferior angle blunt (Fig. 7C-E ). Mandibulatory palp rectangular, with setae on superior margin (Fig. 7F ). Labrum with very hairy crest and a deep cleft (Fig. 7G, H ).

Remarks.

The specimens examined in the present study agree with the original description given by Linnaeus (1758) and the more recent one by Chan et al. (2009). However, in the present specimen, the labrum does not possess teeth whereas the specimen examined by Chan et al. (2009) has three sharp teeth on each side of the cutting edge.

Megabalanus tintinnabulum closely resembles M. validus Darwin, 1854, but differs from the latter in having a conical shell with a coloured external surface. The species also resembles M. volcano (Pilsbry, 1916), but differs from the latter in having the maxillule not notched.

Worldwide distribution.

The species has a cosmopolitan distribution with records from Brazil, Venezuela, European waters (UK, Ireland, Belgium and Netherlands; Southward, 2008) the Mediterranean Sea, Madagascar, Cape of Good Hope, New Zealand, Australia, Singapore, Thailand, Vietnam ( Jones and Hosie 2016), Hong Kong, Taiwan, Japan, and India ( Trivedi et al. 2015).

Distribution in India.

This species has been reported from Gujarat ( Trivedi et al. 2015; Parmar et al. 2018; present study), Maharashtra ( Karande and Palekar 1966), Goa ( Nandakumar 1990), Tamil Nadu ( Krishnamoorthy 2007), Andhra Pradesh ( Rao and Balaji 1988), Odisha (formerly Orissa) ( Pati et al. 2009), West Bengal ( Nilsson-Cantell 1938), Andaman and Nicobar Islands ( Daniel 1972), and the Bay of Bengal ( Nilsson-Cantell 1938).

Figures

Figure 2. Gujarat barnacles A Striatobalanus tenuis (Hoek, 1883) on gastropod shell (Murex ternispina Lamarck, 1822) B top view of Striatobalanus tenuis (BD: 11.28 mm) LFSc. ZRC- 157 C external and internal view of scutum and tergum D Megabalanus tintinnabulum on shores LFSc. ZRC- 182 E external and internal view of scutum and tergum F Amphibalanus amphitrite (Darwin, 1854), top view, (BD: 12.38 mm) LFSc. ZRC- 181, external and internal views of scutum and tergum G Amphibalanus reticulatus (Utinomi, 1967), top view, (BD: 14.99 mm) LFSc. ZRC- 158, external and internal views of scutum and tergum H Chelonibia testudinaria (Linnaeus, 1758) on crab Portunus sanguinolentus I Chelonibia testudinaria (Linnaeus, 1758), top view (BD: 5.33 mm) LFSc. ZRC- 159, internal view of scutum and tergum J Lepas anatifera Linnaeus, 1758, (CL: 16.39 mm) LFSc. ZRC- 162, a. Side view of capitulum K Lepas anserifera Linnaeus, 1758, (CL: 16.28 mm) LFSc. ZRC- 183, Side view of capitulum.

Figure 7. Megabalanus tintinnabulum (Linnaeus, 1758), (BD: 20.28 mm) LFSc. ZRC- 182, Light microscopy on mouth parts A maxilla B maxillule C mandible D close up on the inferior angle of mandible E close up on the teeth of mandible F mandibulatory palp G labrum H close up view on the cutting edge of labrum, showing the teeth. Scale bars in µm.