Agalma elegans   (Sars,  1846) (Hydrozoan)
Organism information awaits expert curation
Class: Hydrozoa

Image copyrights: Observatoire Océanologique de Villefranche sur Mer

Adult specimens, which will only be represented by fragments in the plankton samples, have a terminal pneumatophore, approximately 1 mm in height with a red cap. Often the siphosomal stem is found on its own with the pneumatophore still attached. The nectophores are up to 7 mm in length, v-shaped and have two prominent lateral wings and an internal t-shaped nectosac. The bracts are triangular, approximately 9 mm in length with three terminal projections and a convex dorsal surface.

Gonophores: Clusters of male and female gonophores, borne on short stalks arising from bases of palpons; female ones at proximal and male at distal end of each cormidium.

Gynophores: Round gynophores borne on long thin stalks, in various stages of growth; umbrella and radial canals well developed, with single large ovum in each.

Androphore: Fewer in number, in various stages of development, larger than gynophores, with thin, longer pedicels, and oval in shape with well developed umbrella and radial canals. Spadix fill entire space inside.
Larvae occurring in the plankton: Two larval stages - "Athorybia" stage and "Nectalia" stage occur in plankton.

"Athorybia Stage": 1-1.5 mm long, pneumato¬phore round surrounded by a corona of 6-8 typical larval bracts 4-6 of them thicker, 3 sided, with 3-4 finally serrated ribs or ridges on dorsal surface and 2 large banana shaped nematocysts at tips. Other bracts thinner, broader and leaf-like. Nectosome and siphosome not yet elongated. Siphosome with one gastrozooid, larval type of tentacle and 4-6 palpons.

"Nectalia stage”: Nectosome and Siphosome slightly elongated, 3-8 mm long, with one or two pairs of nectophores, 2 or 3 cormidia and few long, trident bracts surrounding cormidia.

Early Agalma elegans specimens, usually less than 4 mm in length, can be recognised as a young physonectid by the presence of a pneumatophore with a cap tinged dark red.


Synonym (s)
Agalmopsis elegans Sars 1846
Agalma elegans (Sars) 1846
(Senior synonym)
Agalma elegans Bigelow 1911
Agalma elegans Daniel 1974

Common Name (s)
Economic Importance and Threats

Habitat:  Coastal


• Bay of Bengal (Lat: 15) (Long: 90) INDIA
• Bay of Bengal (Record: 1962-1965)
• Arabian Sea (Record: 1962-1965)
• INDIA (Record: 1962-1965)
• Tamil Nadu, Chennai Coast INDIA
• West Coast (Lat: 10.85) (Long: 75.16) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 8.31) (Long: 73.11) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 11.23) (Long: 75) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 11.11) (Long: 75.36) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 10.7) (Long: 75.7) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 14.78) (Long: 74.01) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 15.25) (Long: 73.01) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 15.16) (Long: 72.68) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 16.7) (Long: 71.73) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 72) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 18.5) (Long: 72) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 10.95) (Long: 75.11) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 9.81) (Long: 75.66) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 9.88) (Long: 75.88) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 16.25) (Long: 72.63) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 16.16) (Long: 72.75) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 13.38) (Long: 73) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 9.85) (Long: 73.63) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 12.46) (Long: 73.53) INDIA (Record: 01/1962-12/1963)
• Red Sea (Record: 01/1962-12/1963)
• Gulf of Aden (Record: 01/1962-12/1963)
• Bay of Bengal INDIA
• Arabian Sea INDIA (Record: 01/1962-12/1963)
• West Coast INDIA
• Lakshadweep Sea INDIA

Literature Source(s)
  • Daniel, R (1985) Fauna of India and the adjacent countries (Coelenterata: Hydrozoa: Siphonophora) ZSI 440 pp Available at - NIO, Goa
  • Zoological Survey of India (Eds) (1991) Animal resources of India (Protozoa to Mammalia) ZSI 1-694 Available at - NCL, Pune
  • Conway, DVP; White, RG; Hugues-Dit-Ciles, J; Gallienne, CP and Robins, DB (2003) Guide to the coastal and surface zooplankton of the south western Indian Ocean Occasional publication no 15 Marine Biological Association of the United Kingdom Occasional Publication of the Marine Biological association of the United Kingdom 354 pp Available at -
  • Hussain, SM Brief report on biodiversity in the coastal areas of Pakistan p 113
  • Daniel, R and Daniel, A (1969) Siphonophora collected during the 35th cruise of the R. V. VITYAZ in the eastern part of the Indian Ocean Symposium on Indian Ocean, Part II 571-574 Available at - Library, CAS, Parangipettai
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Sealifebase Available at -
  • Integrated Taxonomic Information System (ITIS) Available at -
  • Observatoire océanologique de Villefranche sur mer Available at -
  • 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 -
  • Rengarajan, K (1973) Siphonophores obtained during the cruises of R. V. Varuna from the west coast of India and the Laccadive Sea Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin, India 15(1) 125-129 Available at -
  • Daniel, R and Daniel, A (1963) On the siphonophores of the Bay of Bengal I.Madras coast2( Journal of the Marine Biological Association of India The marine biological association of India 5(2) 185-220 Available at - NIO, Goa
  • Rengarajan, K (1975) Distribution of siphonophores along the west coast of India and the Laccadive sea Journal of the marine biological association of India The marine biological association of India 17(1) 56-72 Available at - NIO, Goa

Page last updated on:2011-06-06

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