Myrmeconema

  

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Rev: 10/02/2026

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
Return to Myrmeconema Menu Ecosystem Functions and Services
Distribution Management
Return to Tetradonematidae Menu Feeding  References
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Enoplea
Dorylaimia
       Mermithida
Mermithina
Tetradonematoidea
Tetradonematidae

Myrmeconema Poinar & Yanoviak, 2008

Type species of the genus: Myrmeconema neotropicum Poinar & Yanoviak, 2008

    Synonyms:
     

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Morphology and Anatomy:

Diagnostic characteristics of the egnus:

Females:

  • Pharynx greatly reduced; pharyngeal lumen ends shortly after nerve-ring area;
  • Three penetration gland-cells located posterior to nerve-ring area;
  • Intestine greatly reduced, represented by some loosely connected cells continuing through body to faint anal opening;
  • Hypodermal cells well developed;
  • Vulva centrally located; vagina very short, barrel-shaped;
  • Ovaries opposed, filling body cavity with at least 1 and often 2 loops; tips usually reflexed but sometimes outstretched;
  • Ttail bluntly rounded.

Infective Juveniles:

  • Development completed inside egg in uterus of female;
  •  body narrow, elongate; stylet present;
  • Three penetration glands (involved in host penetration);
  • Pharynx and intestine connected; stichocytes not observed; intestinal lumen open, terminating in anus;
  • First molt occurs in egg.

 

 

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

   

Males:

  • Stout, tightly coiled at death;
  • Stylet present, often located sub-terminally;
  • Nerve-ring area reduced;
    Pharynx and intestine degenerate, rarely detected past mid-body;
  • Gonads paired, opposite, outstretched or occasionally reflexed at tip;
  • Spicule single, large, from nearly straight to noticeably
    curved;
  • Ggenital papillae absent;
  • Ttail tip rounded, tightly coiled around female mid-body during mating.

 

Ref: Poinar and Yanoviak (2008).
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Distribution:

Type species described as a parasite of the larvae, pupae and adults of a Neotropical ant, Cephalotes atratus (L.), in Peru and Panama.

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Feeding:

Food Sources and Feeding strategies for the genus Myrmeconema

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Biology and Ecology:

The Tetradonematidae is a small group of mermithoid nematodes

How ants become infected with M. neotropicum is unknown.  Myrmeconema is the only member of the Mermithoidea that causes its host to
radically change colour (from black to red).

The infective stages of M. neotropicum possess a well-developed stylet, penetration glands for entering the host, a complete digestive tract with the pharynx connected to the intestine, and an anus. Similar characters are found throughout the infective stages of mermithid nematodes (Poinar & Hess, 1974).
Penetration glands are a feature of mermithid infective juveniles and are often also seen in early parasitic stages (Poinar, 1975).
A pharynx with stichocytes (cells containing prominent nuclei) are common in mermithids. This characteristic appears to be absent in Mrymeconema, but may be difficult to discern. Mermithids usually have 16 but the number can vary. In the Tetradonematidae there is a tendency for the reduction or complete elimination of the stichocytes.
All mermithids have a prominent intestine, which becomes separated from the remaining alimentary tract and functions as a trophosome (food storage organ). The trophosome provides nutrients to the non-feeding postparasites and adults during their free-living existence. While an anus is sometimes evident in the infective stages of mermithids and tetradonematids, it is often degenerate in the adults (adapted from Poinar and Yanoviak, 2008).

 Myrmecanema, like other Tetradonematidae, has a degenerate intestine since nourishment is obtained directly from the host, probably by direct absorption through the cuticle (Poinar & Hess, 1977).

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Life Cycle:

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

Regulation of host species.

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Management:

 
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References:

Poinar, G.O., Jr 1975. Entomogenous nematodes: a manual and host list of insect-nematode associations (317 pp).Leiden: E. J. Brill.

Poinar, G.O. Jr, and  Hess, R. 1977. Romanomermis culicivorax: morphological evidence of transcuticular uptake. Experimental Parasitology, 42, 27-33.

Poinar, Jr, G., Yanoviak, S.J. 2008. Myrmeconema neotropicum n. g., n. sp., a new tetradonematid nematode parasitising South American populations of Cephalotes atratus (Hymenoptera: Formicidae), with the discovery of an apparent parasite-induced host morph. Syst Parasitol (2008) 69:145–153
DOI 10.1007/s11230-007-9125-3


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Revised by Howard Ferris: October 02, 2026.