Elaphonema

Contents

Rev 04/29/2026

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
Return to Elaphonema menu Ecosystem Functions and Services
Distribution Management
Return to Elaphonematidae Menu Feeding  References
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Classification:

      Chromadorea
        Rhabditida
         Rhabditia

Cephaloboidea
          Elaphonematidae

                Elaphonema Heyns, 1962

The genus Elaphonema, and the type species E. mirabile were described by Dr. Heyns as part of his PhD thesis research under the direction of Gerald Thorne at the University of Wisconsin. I speculate (but do not know)  that the genus name is derived from the lateral fin-like structures which may have reminded Heyns of the ears of an elephant from his native South Africa.

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Morphology and Anatomy:

  • Small nematodes, 0.3 to 0.7 mm
  • Cuticle with coarse striations, 2-2.5 mu wide and fine longitudinal lines
  • Labial region bilaterally symmetrical and directed ventrally. Bordered by lateral fin-like structures.
  • Lips large, leaf-like, widely separated
  • Three labial probolae, not extending beyond lips
  • Slit-like amphid apertures.
  • Stoma short or long, consisting os a series of elements.
  • Esophagus with corpus, isthmus and posterior bulb and distinct cardia.
  • Female monodelphic prodelphic; ovary reflexed beyond.
  • Vulva a tyransverse slit.
  • Anterior lip of anus extendes over as a flap.
  • Male with cephaloboid spicules; no bursa.
  • Both sexes about equally abundant.
  • Tail short

Ref: Heyns, 1962; Andrassy, 2005.
  Elaphonema mirabile. From Heyns, 1962

Females: General characteristics:

  •  Reproductive system cephaloboid, monodelphic-prodelphic
  •  ovary posteriorly directed, on right of intestine, without
    flexures posterior to vulva;
  • oviduct slightly alveolated; spermatheca well developed; uterus cylindrical, differentiated into 2 parts, tubular and swollen
  • vulva protruding or slightly sunken.
  • Rectum with three small gland-like cells around the intestine-rectum junction.
  • Tail conoid, slightly curved ventrally and almost acute tip.
  • Phasmids at mid-length of tail
Ref: Abolafia et al., 2026		 Males: General characteristics:

  • Reproductive systm monorchic: testis reflexed. on right of intestine.

  •  Spicules paired, symmetrical, curved; manubrium rounded; calamus as
    wide as manubrium; lamina ventrally curved with finely rounded tip.

  • Gubernaculum with slightly ventrally curved tip.

  •  Genital papillae three pairs precloacal and five pairs postcloacal:

  • Tail conical, posteriorly ventrad curved with finely rounded or acute terminus.

  • Phasmids located laterally anterior or posterior to a postcloacal genital papilla

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

Specimens of E. mirabile were collected in a variety of locations in South Africa, expecially in sandy soils.

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Feeding:

Food Sources and Feeding strategies for the genus Elaphonema

Bacterial feeding..

The lips bear seta-like or triangular processes of which vary in size and shape in the different species of the genus. The subventral lips have a  triangular
process directed towards the ventral primary axil and one or two short seta-like processes that are directed towards the oral opening. Presumably these structures are involved in the accumulation of bacteria and in directing the food towards the pharynx. Channels at the beginning of the pharynx are curved at their junction with the posterior part of the stoma. The channels are involved in the secretion of fluids that facilitate the aggregation of bacteria on which the nematodes are feeding. Abolafia et al., 2026 provide excellent photomicrographs and 3-D models of the oral structures of Elaphonema spp.

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Biology and Ecology:

It seems reasonable to assume that the elaborate and complex structures of the lip region, stoma and pharynx are adaptations for survival in areas where bacterial food may not be in abundance.

All species of the genus are described and reported from South Africa. I have also seen Elaphonema (species undetermined) in sandy soils of Zimbabwe.

 

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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:

Abolafia, J., Robles, M-C., Pretorius, M., Fourie, H. 2026. Comparative morphology of four species of the genus Elaphonema Heyns, 1962 (Rhabditida, Elaphonematidae) from South Africa, with analysis of the morphology of the lip region and the stoma. Nematology 28:327-343

Andrassy, I. 2005. Free-livinmg nematodes of Hungary I. Hungarian Natural History Museum.

De Smidt, A., Rashidifard, M., Girgan, C., Jansen van Rensberg, C. 2025. Redescription of Elaphonema messinae Van den Berg, Swart & Heyns, 1984 and E. mirabile Heyns, 1962 (Nematoda: Rhabditida) from South Africa, including the first molecular data for the genus. Nematology 27: 981-1000

Heyns, J. 1962. Elaphonema mirabile n. gen., n. sp. (Rhabditida), a remarkable new nematode from South Africa. Proc. Helm. Soc. Wash. 29:128-130

 

 
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Copyright © 1999 by Howard Ferris.
Revised: April 29, 2026 .