Semibalanus madrasensis   Daniel  1958 (Barnacle)
Organism information awaits expert curation
Class: Maxillopoda

Size: Height 5.5-7.5 mm, basal diameter 20-27mm

Color: The parietes are pale brown with the radii white and the alae bluish white.

Greatly depressed with rhomboidal orifice and circular basis.
Shell basis is membranous. The parietes are porous. Externally they are provided with small anastomosing wrinkles near the basal edge. The inner faces of the parietes are smooth at the base without any denticulation. The parietal pores are small; the septa between the pores branching near the outer lamina of the wall.
The radii are very narrow without any pores and the alae are smooth. The compartments are easily separable and the rostrum and carina are almost of the same length (i.e.) rostrum not prolonged downward below the other compartments. The opercular valves are sunken slightly below the peritreme. The tergum has a horst carinal margin. Articular ridge is well developed and articular furrow is very broad. Spur is moderately long, nearly one-third the width of the valve and is pointed at the basal tip and is located very close to the basiscutal angle.
The outer face is flat with a slight depression running to the spur. The scutum has prominent growth ridges. The upper ends are slightly reflexed with the tips projecting as points. The articular ridge is very prominent and the adductor ridge is only faintly visible.
Cirri: The number of segments in the anterior and posterior rami of the cirri is as follows:
I Cirrus-16,13; II Cirrus-12,14; III Cirrus -14,15; IV Cirrus - 24,24; V Cirrus- 24,24; VI Cirrus -26,26.
The pedicels and the basal segments are long. There are no spinules or 'teeth' on any of the cirrus. The 4th, 5th and 6th pairs of cirri are alike. Each segment bears two pairs of long and a pair of short setae. The bristles at the posterior distal angles of the segments are always very short.
Mouth parts- Labrum: With three teeth on either side of the central notch.
Inner maxilla: With the free edge bearing a pair of long spines at the apex and at the base, with three pairs of shorter spines placed in between. A notch is present above the lower pair of spines placed in between. A notch is present above the lower pair of spines. Outer maxilla is rounded and broad.
Mandible provided with five teeth and a stout spine at the lower angle. The distance between the first and second teeth is almost equal to that between the second and third teeth. The fourth and fifth teeth are very near to each other and the third basal margin. At the lower angle there is a distinct stout spine.

Synonym (s)
Semibalanus madrasensis Daniel 1958

Common Name (s)
Economic Importance and Threats



• Tamil Nadu, Chennai Coast INDIA (Record: 1955 - 1956)

Literature Source(s)
  • Fernando, SA (2006) Monograph on Indian Barnacles Ocean science and technology Cell, Kochi 9-199 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

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