Octolasmis tridens   (Aurivillius),  1893 (Barnacle)
Organism information awaits expert curation
Class: Maxillopoda

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

Size: Capitular length 5 mm with breadth of 3.5 mm; peduncle length 9 mm, breadth 1.5 mm. Capitulum oval; valves well developed, calcified and opaque.

Scutum: Consisting of two segment sickle shaped with upper extremity blunt and extending a little higher than the upper extremity of carinal segment. In full grown specimens carinal segment approximated closely to occludent; separated from carina to a considerable extent.
Tergum: Triangular; anterior part of scutal margin deeply excavated to received apex of occludent segment of scutum.
Carina: Curved, broad and expanding at the base into a well developed transverse discs, somewhat concave externally in this region with a broad flat inferior margin; a dorsal ridge present on entire length of carina; apex situtated at a point about half the distance between carinal angle and umbo of tergum.
Peduncle: Short or moderately long and slender; base always broader than the region where it joins capitulum; surface either ringed or smooth with numerous chitinous points covered all over.
Caudal appendages: compressed and variable in length; reach the tip of first segment of sixth cirri; bears long slender hairs; naked edges without hairs.
Mouth parts: (i) Labrum: Distinctly bullate. Closely spaced 20-22 sharp conical teeth observed on the labral crest.
(ii) Mandible: With 5 teeth; the fourth and fifth angle close together and usually bifid; sometimes fifth teeth with 3-4 small and slender teeth; superior margin with three clusters of setae equally spaced; inferior margin with series of setae.
(iii) Inner maxilla: Distinctly notched cutting edge, below two large and equally long spines; lower part with 5-6 spines of varying length and breadth interspersed with minute spines; superior margin with only 4 clusters of setae, 3 in each; inferior margin slightly sinuate at 6 points each with 2-3 setae; body surface clothed with numerous fine setae.

Synonym (s)
Poecilasma tridens Aurvillius 1893
Dichelaspis occlusa Lanchester 1902
Dischelaspis tridens Annandale 1909
Octolasmis tridens Nilsson-Cantell 1938a

Common Name (s)
Economic Importance and Threats



• Tamil Nadu, Parangipettai INDIA (Record: 2002)
• Bay of Bengal (Record: 2006)
• Tamil Nadu, Off Chennai Coast INDIA (Record: 2006)
• Tamil Nadu, Gulf of Mannar INDIA (Record: 2003)
• Tamil Nadu, Chennai Coast INDIA (Record: 2008)

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 - http://www.marinespecies.org
  • Marine Biological Station, Chennai, Tamil Nadu (2003) Checklist of marine fauna of Tamil Nadu Department of Environment, Government of Tamil Nadu Available at - http://tnenvis.nic.in
  • Dr. Ramesh, R; Dr. Nammalwar, P and Dr. Gowri, VS (2008) Database on coastal information of Tamil Nadu Report Submitted to Environmental Information System (ENVIS) Centre, Department of Environment, Government of Tamil Nadu Institute for Ocean Management, Anna University, Chennai, Tamil Nadu. Available at - http://tnenvis.nic.in/PDF/coastal%20data.pdf

Page last updated on:2012-05-21

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