Octolasmis warwickii   Gray,  1825 (Barnacle)
Organism information awaits expert curation
Class: Maxillopoda

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

Size: Capitular length 11.5 mm; breadth 10 mm; peduncle length 13 mm; breadth, 3.5 mm.

Capitulum irregularly ovoid and laterally composed; occludent margin nearly straight; slightly depressed where vertical branch of the scutum ends; carinal margin broadly arched; apex usually bluntly pointed and at times rounded. Capitular membrane semi-transparent; often thick and dark purple; some times deep orange; the calcified valves although widely separated from each other, cover about half the surface of the capitulum.
Carina: Bow shaped, narrow, extending upwards far above the carinal angle of the tergum; slightly concave inside; on the basal third or quarter, directed inward divided transversely into two pieces or plates; basal plate well developed, buried in and running parallel to and below the basal margin of the scutum; basal plate terminated in a large, broad flat rectangular and slightly concave disc; lateral surfaces of the disc usually ridged; lateral margin of the disc deeply notched.
Scutum: Separated into two segments; occludent segment nearly straight and dagger shaped, slanting outward from the occludent margin of the capitulum; apex separated from the scutal margin of the tergum but corresponds to the excavation of the tergum; carinal segment sub-triangular and much reduced than the occludent segment; carinal margin broadly concave.
Tergum: Axe shaped with stout lower arm, disproportionately longer in young and adult; slanting downwards towards scutal margin of the carina; vertically, the lower arm slightly depressed; third projection of tergum near apex absent in young forms; occludent margin smooth in young specimens and stepped in adults.
Peduncle: Distinct from capitulum; stout and cylindrical; usually narrow towards the base; body transparent with sparsely scattered chitinous points or spines.
Caudal appendages: Slender and unsegmented, reaching the tip of the pedicel of the sixth cirrus; curving outwards from the base; tip rounded with a group of 30-35 terminal setae; posterior margin with a row of fine setae.
Mouth parts: Labrum: Annandale (1909) reported the presence of a row of large teeth. Fernando (2006) observed that the labrum is bullate bearing minute teeth. with fine setae dispersed between them. Daniel (1955c) did not mention about the labrum.
Mandible: Five major teeth with inferior angle highly pectinated bearing five to seven spines; at times specimens bear mandibles of varying teeth structures, having 2nd, 3rd and 4th bifid and 5th blunt; sometimes the cleft between 3rd and 4th bears a small additional tooth; superior margin with very few setae; inferior margin with a row of fine hairs of equal length; the body of the mandible with fine short spinules concentrating near the base of the last three teeth.
Inner maxilla: Cutting edge almost straight with a deep notch bearing 2-3 slender and short spinules; above the notch normally two long and stout spines (sometimes three); below the incisure 10-12 smaller spines; superior margin with clusters of setae spaced at equal distance; inferior margin straight with a row of 8-10 strong spinules; the body bears long, strong spinules especially at lower region.

Synonym (s)
Dichelaspis eguina Annandale 1906b
Dichelaspis eguina Lanchester 1902
Dichelaspis warwickii Darwin 1851
Dischelaspis warwickii Annandale 1909a
Octolasmis warwickii Barnard 1924
Octolasmis warwickii Nilsson-Cantell 1938

Common Name (s)
Economic Importance and Threats

Habitat:  Estuarine, Coastal


• Tamil Nadu, Chennai (Lat: 13.09) (Long: 80.29) INDIA
• Tamil Nadu, Tharangambadi INDIA (Record: 2001)
• Tamil Nadu, Chennai INDIA (Record: 2006)
• East Coast INDIA (Record: 2006)
• Tamil Nadu, Pulicat Lake INDIA
• West Bengal, South 24 Parganas INDIA

Literature Source(s)
  • Ramakrishna; Sarkar, J and Talukdar, S (2003) Marine invertebrates of Digha coast and some recomendations on their conservation Records of the Zoological Survey of India ZSI, Kolkata 101(3-4) 1 Available at - NCL, Pune
  • Jeffries, WB; Voris, HK and Yang, CM (1989) Observations on the incidence of the pedunculate barnacle, Octolasmis warwickii (Gray, 1825) on horseshoe crabs (Xiphosura) in the seas adjacent to Singapore The Raffles Bulletin of Zoology 37 58-62 Available at - Zoological Records
  • Jeffries, WB; Voris, HK and Chang Man Yang (1982) Diversity and distribution of the pedunculate barnacle Octolasmis in the seas adjacent to Singapore Journal of Crustacean Biology 2 (4) 562-569 Available at - Zoological Records
  • 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
  • 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
  • Raj, PJS (2006) Macro fauna of Pulicat lake NBA bulletin No.6 NBA Available at - http://www.nbaindia.org/docs/bulletin6-pulicatlake.pdf
  • Roy, MK (2010) Diversity and Distribution of Crustacea Fauna in wetlands of West Bengal Journal of Environment and Sociobiology Social Environmental and Biological Association, Kolkata, India 7(2) 147-187 Available at - NIO,Goa

Page last updated on:2011-10-25

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