Abylopsis tetragona   Otto,  1823 (Hydrozoan)
Organism information awaits expert curation
Class: Hydrozoa

Image copyrights: Animal Pictures Archive

Polygastric phase: Anterior nectophore: Size: 7 mm long; 5.67 mm broad nectosac 5 mm, somatocyst 4 mm and hydroecium 3.47 mm in length. With 6 facets- 1 dorsal, 1 ventral, 2 apico-lateral, 2 ventro-lateral; dorsal facet smaller than ventral, pentagonal, elongated. Ridges usually smooth, rarely serrated at mouth of hydroecium. Somatocyst with oval-shaped base and thin; elongate apical branch. Apex of nectosac extend above main body of somatocyst in dorsal view (diagnostic character). Hydroecium small, conical, lying between and below nectosac and somatocyst. Nectosac long slightly bent towards dorsal facet in large nectophores. Lateral radial canals highly arched.

Posterior nectophore: Size: 26 mm long; 9.47 mm broad, three times as long as wide, 3 to 3 ½ times longer than anterior nectophore when fully grown. Apophysis small, oblique. With five complete ridges-one dorsal, two lateral ridges (left and right) and two ventral ridges; dorsal end in inconspicuous tooth and laterals in prominent teeth; ventrals form edges of hydroecial wings and end in asymmetrical teeth. Proximal part of hydroecial canal covered by a flap from left hydroecial wing (left ventral ridge). Proximal end of inner margin of right hydroecial wing bear nine comb-teeth. Left hydroecial wing closed in position between comb teeth and small cone-like projection from middle of hydroecial wing. Truncated apical portion of nectophore articulates with almost whole of ventral wall of anterior nectophore.

Nectosac with four radial canals arising from pedicular canal at apex of nectosac but with an extra blind ending canal arising from rete at junction between circular canal and ventral radial canal toward left and terminating near a blind down growth from displaced left lateral radial canal; new canal lying under left ventral ridge.

Eudoxid phase: Referred to as "Aglaisma": Bract 6.3 mm long; 4.7 mm broad, apical half cuboidal in shape (apical, ventral and lateral facets square in shape), with elongated, irregularly pentagonal dorsal facet. Lateral facets deep, with basal cross ridge lying far below level of lateral branches of phyllocyst. Phyllocyst with four branches-thin, thread-like anterior and posterior branches, and two thick bean-shaped lateral branches. Bracteal cavity deep, broadly conical.

Gonophore: Length ranging from 3.2 mm to 6 mm with four complete ridges, all ending in four teeth at ostium. Radial canals simple and straight. Manubrium shrink very much after shedding eggs or sperms and appear like special nectophore.

Synonym (s)
Abylopsis tetragona Bigelow, 1911
Abylopsis tetragona Daniel, 1974
Pyramis tetragona Otto, 1823

Common Name (s)
Economic Importance and Threats

Habitat:  Pelagic, Coastal


• Bay of Bengal (Lat: 15) (Long: 90) INDIA
• Bay of Bengal INDIA (Record: 1962-1965)
• Arabian Sea INDIA (Record: 1962-1965)
• Kerala, Off Kochi INDIA (Record: 1962-1965)
• West Coast INDIA (Record: 1962-1965)
• Tamil Nadu, Kanniyakumari INDIA (Record: 1962-1965)
• Tamil Nadu, Chennai Coast INDIA (Record: 1962-1965)
• Andaman and Nicobar Islands, Nicobar Islands INDIA (Record: 1962-1965)
• Andaman and Nicobar Islands, Andaman Islands INDIA (Record: 1962-1965)
• Lakshadweep (Lat: 10.95) (Long: 74.76) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 10.05) (Long: 75.7) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 9.9) (Long: 75.95) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 9.83) (Long: 75.63) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 9.2) (Long: 75.9) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 8.76) (Long: 76.08) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 8.5) (Long: 74.16) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 8.31) (Long: 73.11) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 8.25) (Long: 73.06) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 8.28) (Long: 72.95) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 11.25) (Long: 75.18) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 10.56) (Long: 75.66) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 10.63) (Long: 75.75) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 10.7) (Long: 75.7) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 10.58) (Long: 75.41) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 15.4) (Long: 73.7) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 15.31) (Long: 73.35) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 15.25) (Long: 73.16) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 71.25) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 71) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 70.51) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 69.75) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20) (Long: 69.25) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20.93) (Long: 68.83) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 20.48) (Long: 70.06) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 18.5) (Long: 72.25) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 18.5) (Long: 70.75) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 18.5) (Long: 70.43) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 18.5) (Long: 70) INDIA (Record: 01/1962-12/1963)
• West Coast (Lat: 17) (Long: 71.5) INDIA (Record: 01/1962-12/1963)
• Lakshadweep (Lat: 9.68) (Long: 75.16) INDIA (Record: 17/11/1963)
• Lakshadweep (Lat: 9.93) (Long: 76.15) INDIA (Record: 18/11/1963)
• West Coast (Lat: 16.41) (Long: 73.11) INDIA (Record: 07/12/1963)
• West Coast (Lat: 15.45) (Long: 71.36) INDIA (Record: 08/12/1963)
• West Coast (Lat: 14.66) (Long: 73.66) INDIA (Record: 11/12/1963)
• West Coast (Lat: 13.38) (Long: 73) INDIA (Record: 11/12/1963)
• West Coast (Lat: 9.88) (Long: 75.83) INDIA (Record: 18/12/1963)
• West Coast (Lat: 12.73) (Long: 74.73) INDIA (Record: 21/12/1963)
• West Coast (Lat: 15) (Long: 69) INDIA (Record: 12/09/1986-26/09/1986)
• West Coast (Lat: 19) (Long: 73) INDIA (Record: 12/09/1986-26/09/1986)
• South West Coast INDIA
• Lakshadweep Sea INDIA
• South West Coast INDIA
• Tamil Nadu, Chennai Coast INDIA
• West Coast INDIA
• 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
  • Zoological Survey of India (Eds) (1991) Animal resources of India (Protozoa to Mammalia) ZSI 1-694 Available at - NCL, Pune
  • Balasubramanian, T Lagoons of India Environmental Information System Centre, Envis Publication Series: 3/2001 105 pp Available at - http://aucasmbenvis.org/files/04-Publications/lagoon%20status.pdf
  • (2001) Invertebrate zoology collections Available at - http://goode.si.edu/mcs/iz/Query.php
  • Hussain, SM Brief report on biodiversity in the coastal areas of Pakistan p 113
  • 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/
  • Animal Photo Album Available at - http://www.animalpicturesarchive.com/
  • 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
  • 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 - http://eprints.cmfri.org.in/1580/1/Rao_125-259.pdf
  • Madhupratap, M; Nair, SRS; Haridas, P and Padmavati, G (1990) Response of zooplankton to physical changes in the environment: coastal upwelling along central west coast of India Journal of coastal research Coastal Education and Reserch Foundation 6 413-426 Available at - http://drs.nio.org/drs/handle/2264/2439
  • Rengarajan, K (1983) Quantitative and seasonal abundance of siphonophores along the southwest coast of India and the Laccadive sea Journal of marine biological association of India The marine biological association of India 25(1&2) 17-40 Available at - NIO, Goa
  • 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
  • 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 - http://map.seafdec.org/downloads/BIMSTEC/010-Zooplankton-Issaporn.pdf

Page last updated on:2011-06-23

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