Rhizophysa filiformis   (Forskal,  1775) (Hydrozoan)
Organism information awaits expert curation
Class: Hydrozoa

Size: 30-100 cm long.

Pneumatophore: 12 by 8 mm, cap of red pigment around apical pore. No septa, cavity filled with hypocystic villi containing giant gas gland cells.

Siphosome: Thin, long, with numerous pale green colored gastrozooids occurring on one side of stem only. Younger gastrozooids with underdeveloped bud-like tentacle at base occur just below pneumatophores. Mature gastrozooids placed 2-3 cm apart, 8-10 mm long. Developmental stages of tentilla traceable in young gastrozooids.

Tentacle: 3 types, depending on growth stages, distal tip knob-like in young tentilla. Tricornuate numerous, with median thicker lobe and two thinner and shorter or longer lateral lobes, nematocysts at tips. 10 or 12 tricornuate, branches with web connecting lateral to central branch. 17 or more dentritic or palmate tentilla.

Gonodendron: Male or female, between two gastrozooids; with long stalk, 20-24 branchlets each with 3 or 4 pairs of sessile gonophores, sub-terminal gonopalpon and single asexual nectophore at side.

Gonophore: Androphore and gynophores alike in shape, size, position on branchlets and reduced into sporosacs. Androphore with spadix bearing sperms. Gynophores with oval shaped ova borne on sinous band.

Synonym (s)
Physophora filiformis Forskal, 1775
Rhizophysa filiformis Bigelow, 1911
Rhizophysa filiformis Daniel, 1974

Common Name (s)
Economic Importance and Threats

Habitat:  Pelagic


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

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 - http://www.marinespecies.org
  • Sealifebase Available at - http://www.sealifebase.org/
  • Boltovskoy, D (Ed.) Zooplankton of the South Atlantic Ocean Marine Species Identification Portal Available at - http://species-identification.org/species.php?species_group=Zsao&menuentry=inleiding

Page last updated on:2011-09-09

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