Nygellus

  

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Rev 06/16/2023

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
Return to Nygellus Menu Ecosystem Functions and Services
Distribution Management
Return to Nygellidae Menu Feeding  References
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Classification:

Enoplea
Dorylaimia
      Dorylaimida
Nygolaimina
Nygellidae
Nygellinae
       Nygellus  Thorne, 1939
Type species of the genus: Nygellus clavatus Thorne, 1939

Nygellus  is distinct among dorylaims in having characteristics of both the superfamily Nygolaimoidea in having a mural tooth, and the superfamily Belondiroidea in having a spiral muscle sheath around the expanded portion of the esophagus. Jairajpuri (1964) established the family Nygellidae for the genus.. Authors have differed over whether the Nygellidae (and Nygellus) should be in the Nygolaimoidea or the Belondiroidea but Ahmad and Jairajpuri (1981) suggested that the combination of a mural tooth and cardiac glands indicated placement in the Nygolaimoidea.  They noted that a spiral sheath has been described for saome other dorylaims outside that superfamily..

 

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Morphology and Anatomy:

      

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 Female:  

  • Medium size, under 2 mm long.

  • Cuticle thin and with fine transverse striations.

  • Lip region continuous with body contour; lips amalgamated.

  • Spear a mural tooth.

  • Cheilostom simple.

  • Expanded basal portion of the esophagus surrounded by a conspicuous spiral sheath.

  • Esophago-intestinal junction with three cardiac cells.

Female:

  • Genital system monodelphic, opisthodelphic.

  • Vagina without sclerotized pars refringens vaginae.

  • Vulva a transverse slit.

  • Female tail clavate.

 

Ref. Pena-Santiago (2006)
Males:   unknown


Body size range for the species of this genus in the database - Click:
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Distribution:

 

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Feeding:

Classified as predators (Yeates et al, 1993).

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Biology and Ecology:
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Life Cycle:

 
For Ecophysiological Parameters for this genus, click 
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Ecosystem Functions and Services:

 

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Management:

 

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References:

Ahmad, M.  and Jairajpuri, M.S. 1981. .Notes on the systematic position of the genus Nygellus Thorne, 1939. Indian J. Nematology 11:114-115.

Andrassy, I. 2009. Free-living Nematodes of Hungary III.  Hungarian Natural History Museum, Budapest. 608p.

Heyns, J. 1968. A monographic study of the nematode families Nygolaimidae and Nygolaimellidae. Republic of South Africa Entomology Memoirs 19.

Heyns, J. 1982. On the authority for the family Nygellidae. Nematologica 28:452-453.

Jairajpuri, M.S. 1964. Studies on Nygellidae n. fam. and Belondiridae Thorne, 1939 (Nematoda: Dorylaimoidea) with description of ten new species from India. Proc. Helminthol. Soc. Washington 31:173-187.

Pena-Santiago, R. 2006. Dorylaimida Part 1. Superfamilies Belondiroidea, Nygolaimoidea and Tylencholaimoidea. Pp 326-391 in  E. Abebe, Istvan Andrassy, W. Traunspurger (eds) Freshwater Nematodes: Ecology and Taxonomy. CABI Publishing.

Thorne, G. 1939. A monograph of the nematodes of the superfamily Dorylaimoidea. Capita Zool. 8: 1-263.

Yeates, G.W., T. Bongers, R. G. M. De Goede, D. W. Freckman, and S. S. Georgieva. 1993. Feeding habits in soil nematode families and genera—An outline for soil ecologists. Journal of Nematology 25:315-331.

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Copyright © 1999 by Howard Ferris.
Revised: June 16, 2023.