Amphicaryon acaule   Chun,  1888 (Hydrozoan)
Organism information awaits expert curation
Class: Hydrozoa

Polygastric phase: Two nectophores of unequal size and shape. No reserve buds present. Older larger larval nectophore retained; younger heteromorph nectophore embraced by larger one, vestigeal, and shield-like in shape.
Functional Nectophore: Smooth, devoid of ridges, round to oval in shape, 2.5-4.5 mm long (largest upto 15 mm in height) 3.4-4.3 mm broad. Nectosac well developed, 0.93-1.6 mm long, 0.55-1.4 mm wide, with broad ostium 1.4 mm in diameter. All radial canals simple straight, unbranched, join circular canal at ostium; ostium lying slightly below surface of nectophore. Somatocyst small, distinct and curved. Hydroecium large, circular in shape, shallow, occurring on upper lateral side of nectophore. Stem long, highly contractile, bearing many cormidia.
Vestigeal Nectophore: Nearly circular, flat, firm, shield-like in shape, 2.33-3.45 mm in length, 2.16-3.25 mm in breadth, inner concave surface fit like a shield over hydroecium of larger nectophore forming a cavity for retraction of stem and cormidia. Somatocyst small thin short canal occurring on inner concave surface. Nectosac highly reduced, non-functional, no ostium; with 4 simple, straight radial canals which join at their distal ends; no circular canal.
Eudoxid phase: Older cormidia detach from polygastric phase, lead independent life. Bract dome shaped 2 mm long, 1.6 mm broad, smooth without any ridges. Bracteal or hydeoecial cavity deep, conical with phyllocyst occurring as two lateral bracteal canals originating from slightly enlarged central body. Dorsal and ventral branches not developed. Single grastrozooid, tentacle with tentilla bearing kidney-shaped cnidosacs. Gonophores smooth, devoid of ridges, rounded in shape; 1.4 mm long, 1.2 mm broad, manubrium bearing germ cells. Nectosac well developed, with broad ostium and 4 simple unbranched radial canals. Each eudoxid with either male or female gonophores. Female gonophore bears 4 ova on manubrium.

Synonym (s)
Amphicaryon acaule Chun, 1888
Amphicaryon acaule Bigelow, 1911
Amphicaryon acaule Daniel, 1974

Common Name (s)
Economic Importance and Threats

Habitat:  Pelagic


• Andaman and Nicobar Islands, Andaman Islands (Lat: 10) (Long: 93) INDIA
• Arabian Sea INDIA (Record: 1962-1965)
• Bay of Bengal INDIA (Record: 1962-1965)
• INDIA (Record: 1962-1965)
• Andaman and Nicobar Islands, Andaman Islands INDIA (Record: 1962-1965)
• Bay of Bengal INDIA

Literature Source(s)
  • Daniel, R (1985) Fauna of India and the adjacent countries (Coelenterata: Hydrozoa: Siphonophora) ZSI 440 pp Available at - NIO, Goa
  • 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 -
  • Jitlang, I; Pattarajinda, S; Mishra, R and Wongrat, L (2007) Composition, Abundance and Distribution of Zooplankton in the Bay of Bengal The Ecosystem-Based Fishery Management in the Bay of Bengal 65-92 Available at -
  • Marine Species Identification Portal Available at -

Page last updated on:2011-09-08

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