Nanomia bijuga   (Delle Chiaje,  1844) (Hydrozoan)
Organism information awaits expert curation
Class: Hydrozoa

Image copyrights: DiComp

Size: Grows upto 45 cm long.

Color: Pinkish in living condition, with red pigmented spots on nectosome and nectophores; gastrozooids and palpons with network of red pigment.

Elongated, slender, highly contractile.

Pneumatophore: 1.8-2 mm long, 1-2 mm diameter, with 8 septa. Apex with light brown pigment spots, surrounded by wine red colored polygonal pigmented cells.

Nectosome: One fifth of total length with 8-25 pairs of biserial and alternate nectophores. Red pigment spots occur on nectosome at points of attachment of nectophores.

Nectophores: Square-shaped when viewed from abaxial or axial sides, flattened from stem-side to ostial side. Upper lateral corners with sharp ear-like expansions. 1.33 mm to 3.67 mm long and 1.17 mm to 3.17 mm broad. Soft, almost round-shaped in living condition, highly transparent with red pigment spots on velum of ostium at junction of lateral radial canals. Nectosac not extending into lateral ear-like extensions, with bulged rounded appearance. Ostium directed dorsally. Lateral radial canals long and looped; loops situated higher up than in any other species of Agalmidae. Mouth plates small and clefted.Two dorso-lateral ridges extend from apices of lateral wings to ostium. Vertical ridges present but faintly marked.

Siphosome: Four-fifth of total length, slender, highly contractile, with dissolved cormidia.

Gastrozooids: Twenty-four fully formed, well spaced gastrozooids in a colony 45 cm long. 8 mm by 2 mm, stalked. Basigaster well developed, with extensible probosis and flexible mouth opening. Network of red pigment at base and irregular red spots around mouth. Red pigment patches on stem.

Tentacle: Protosiphon (primary gastrozooid) with larval type of tentilla; other gastrozooids with adult type. At times larval type of tentilla persist in all gastrozooids in colonies measuring 10-20 mm long.

Larval type of tentilla: With many tentilla ending in rounded cnidosacs; with 6-8 proximal, bean shaped, large and distal radially arranged cigar shaped slender nematocysts; 6-8 stiff bristles (cnidocils) at distal surface; without terminal filament.

Adult type of tentilla: 6-8 tentilla in a tentacle; with coiled maroon colored cnidoband 2 ½ turns and single terminal filament (unicornuate) covered at base with involucrum.

Palpons: About 6 palpons in a row on ventral side of internode between two gastrozooids. Network of red pigment at base, and transparent at distal half. Palpacles very fine, short, threadlike. Male and female gonodendra alternate at bases of palpons.

Female Gonodendra: Gonophores borne on long stalk of gonodendron as two bunches of grapes, on one side at base of a palpon. Each gonophore very small, sessile, highly reduced, with a single ovum.

Male Gonodendra: Stalk of gonodendron highly reduced; with 2 or 3 pedicelate gonophores on other side of same palpon (bearing female gonodendron) at its base; largest gonophore with a short stalk, elongated and saccular in structure (i.e. without medusoid umbrella). Smaller ones budded from base of predecessor.

Bracts: Numerous, covering entire stem. Two types, single large ones situated at base of each gastrozooid; numerous smaller ones along entire stem. Large bracts, broad, thicker, trident, and at times folded to form chambers for retraction of gastrozooids. Smaller ones, thin, stiff, tetragonal shaped, attached at right angles to stem by pointed small peg-like pedicels. Bracteal canal extends to tip of central teeth.

Synonym (s)
Physophora bijuga delle Chiaje, 1844
Stephanomia bijuga (Delle Chiaje, 1842)
Physophora bijuga Della Chiage, 1841
Nanomia bijuga Daniel, 1974
Stephanomia bijuga Bigelow, 1911

Common Name (s)
Economic Importance and Threats

Habitat:  Coastal


• Bay of Bengal INDIA (Record: 1962-1965)
• Arabian Sea (Record: 1962-1965)
• West Coast INDIA (Record: 1962-1965)
• Andaman and Nicobar Islands, Andaman Islands INDIA (Record: 1962-1965)
• Tamil Nadu, Chennai Coast INDIA
• Westcoast (Lat: 11.31) (Long: 75.01) INDIA (Record: 01/1962-12/1963)
• Westcoast (Lat: 11.23) (Long: 75) INDIA (Record: 01/1962-12/1963)
• Westcoast (Lat: 11.06) (Long: 75.11) INDIA (Record: 01/1962-12/1963)
• Westcoast (Lat: 11.16) (Long: 75.45) 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
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Sealifebase Available at -
  • 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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