Membranobalanus longirostrum   (Hoek),  1913 (Barnacle)
Organism information awaits expert curation
Class: Maxillopoda

Image copyrights: Ocean Science and Technology Cell, CUSAT, Kochi

Size: Height 8 mm; diameter 4 mm

Color: White

Laterally compressed with a large orifice and a membranous oval basis. The walls of the shell are thin. The compartments are weakly united, not porose, and held in position by the epidermis. The rostrum is boat-shaped; it is two and a half times as long as the other compartments, with a median longitudinal furrow extending externally as far as the apex. The upper one-third of the rostrum is broad, with the lower two-thirds very narrow and tapering to a point; the top is rounded. The lateral compartments are twice as broad as the carina. The carinolaterals are very narrow, being one fifth as wide as the laterals. The carina is strongly arched with the upper half very narrow and the apex pointed. In many of the specimens the apices of all compartments are corroded and irregularly worn. The radii are very narrow; the sutural edges are not septate. The basal edges of the compartments are smooth and beveled. The alae are weak and have oblique summits. The parietes are smooth with faint growth lines. The basis is membranous.
The scutum is sculptured externally with close deeply cut ridges and without any longitudinal external depressions. The basal margin is strongly arched with the tergal margin almost straight and the occludent margin with strong teeth. Internally the scutum shows a straight well-developed adductor ridge, which runs to the basal margin, close to the lateral depressor muscle pit. The adductor scars are well marked. The articular ridge is high and angular, being half as long as the tergal margin.
The tergum is much wider than the scutum, it is slightly beaked. Externally it is flat, and sculptured with close deeply cut growth ridges. The articular ridge is long with the articular furrow wide. The spur is extremely short, being one third as wide as the basal margin; it stands extremely close to the basiscutal angle and finally curves into it. There are no crests for depressor muscles.
The number of segments in the anterior and posterior rami of the cirri in the specimens examined is as follows:
Cirrus I: 8-10, 18-22. Cirrus II: 9-10, 9- 10. Cirrus III: 12-14, 12-13. Cirrus IV: 23-26, 33-36. Cirrus V: 43-46, 46-48. Cirrus VI: 43-46, 46-48.
The first cirrus has very unequal rami, the posterior ramus being about one third as long as the anterior. The segments of the anterior ramus protrude. The second and third cirri are alike in shape and structure and do not bear any recurved teeth. In the fourth cirrus all segments of the outer ramus are armed with upward curved teeth on the anterior protuberance. The fifth and sixth cirri do not possess these teeth. Each segment of the fifth and sixth cirri bears three pairs of setae of different length.
The penis is nearly thrice as long as the sixth cirrus and has a few short hairs at its distal end; there is a minute point on the dorsal side near the proximal end.
The labrum has three teeth on each side of the central deep notch. The mandible bears six teeth. The first, second and fourth teeth are prominent and large. The third tooth is very short. The fifth and sixth teeth are very blunt. At the inferior angle of the mandible there is a long spine with two smaller spines about it. The first maxilla has the free edge straight and the upper pair of spines very large. There are six smaller spines below the large upper pair and two very large spines below. The second maxilla is oval and fringed with several hairs.

Synonym (s)
Balanus (Membranobalanus) longirostrum Hoek 1913
Balanus (Membranobalanus) longirostrum Nilsson-Cantell 1921
Balanus (Membranobalanus) longirostrum Sundara Raj 1927
Balanus (Membranobalanus) longirostrum Broch 1931
Balanus (Membranobalanus) longirostrum Nilsson-Cantell 1938a
Balanus longirostrum var. krusadaiensis Daniel 1956
Balanus (Membranobalanus) basiscupula Suhaimi 1966
Balanus (Membranobalanus) roonwali Premkumar and Daniel 1968

Common Name (s)
Economic Importance and Threats



• Andaman and Nicobar Islands, Great Nicobar Island, Dongi Nallah INDIA (Record: 2001)

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 -

Page last updated on:2012-05-21

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