Rev 07/18/2020

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           Acrobeles von Linstow, 1877


Seleborca Andrassy, 1985

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Morphology and Anatomy:

Andrassy (1985) separated Seleborca from Acrobeles  mainly by the presence of a double cuticle and a lateral field with four incisures, two simple outer and two crenate or wavy inner lines. However, Shahina andf De Ley (1997) considered that the double cuticle feature had arisen independently in several genera and that the character was insufficient to establish a new genus.  They synonymized Seleborca with Acrobeles.  Species of Acrobeles are currently (2019) considered to be separated into two groups: the "Complexus group" with a double cuticle and the "Ciliatus group" with a single cuticle (Abolafia et al., 2019).

Distinguishing characteristics separating Seleborca and Acrobeles as described by Andrassy (1985) are:
(1) Cuticle double, outer layer thinner and inner layer thicker, heavily annulated in Seleborca; cuticle single in Acrobeles.
(2) Cuticle  structure  in Seleborca simple, rarely punctated, never divided into blocks by longitudinal striae. Cuticle in Acrobeles often
ornamented, simple or rarely divided into blocks by longitudInal lines.
(3) Lateral field in Seleborca with four incisures, two simple outer lines and two corrugated wavy inner lines; in Acrobeles there are two or
three incisures, the outer lines simple or slightly crenate.
Head structures and other morphological characters are similar in both genera.

Head end showing probollae and cuticular pattern of Acrobeles farzanae, an example of the cuticular pattern divided into blocks.
Photograph from Heyns, 1995


Acrobeles complexus
(source: Paul de Ley)

Lip region with triangular lips and bifurvcated labial probollae, bordered by trianguklar tines.

Stoma distinctly jointed, cheilostom wide followed by a funnel-shaped or narrow posterior part with heavy wall.

Cuticle double (complexus group) or single (ciliatus group).

Esophageal corpus cylindrical, isthmus present but sometimes indistinct, terminal bulb always valved. 

Tail of both sexes usually short.

Cuticle striated, often with two layers.

Female: gonad single, anterior directed usually reflexed several times. 

Acrobeles sp. - labial probollae
SEM photomicrograph from Nadler et al., 2006
  Male, whole body


Male: bursa absent but genital papillae present. 

Spicules paired, gubernaculum present. 

Male tail Spicules and gubernaculum

Photomicrographs by Howard Ferris

Body size range for the species of this genus in the database - Click:
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Prevalent in arid soils.

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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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Abolafia, J. E. Shokoohi, G. Du Preez and H. Fourie. 2019. Description of Acrobeles aenigmaticus sp. n. (Rhabditida: Cephalobidae), an unusual species with a poorly developed vulva, from the Kalahari Desert (Ngamiland, Botswana). Nematology 21:319-332.

Andrassy. I. 1985. A dozen new nematode species from Hungary.Opuscula Zoologica, Budapest. 19: 3-39.

Heyns, J. 1995. Acrobeles farzanae spec. nov. and Seleborca complexa (Thorne) from the West Coast National Park and Rocher Pan Nature Reserve (Nematoda: Cephalobidae). Koedoe 38:105-113

Nadler, S.A., DeLey, P.,Mundo-Ocampo, M., Smythe, A.B.,Stock, S.P., Bumbarger, D., Adams, B.J., Tandingan De Ley, I., Holovachov, O., Baldwin, J.G. 2006. Phylogeny of Cephalobina (Nematoda): Molecular evidence for recurrent evolution of probolae and incongruence with traditional classifications. Molecular Phylogenetics and Evolution. 40: 696-711.

Shahina, F., and De Ley, P. 1997. Two new species of Cephalobidae from Valle de la Luna, Argentina, and observations on the genera Acrobeles and Nothacrobeles (Nematoda: Rhabditida). Fundamental and Applied Nematology 20: 329-347.

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Copyright © 1999 by Howard Ferris.
Revised: July 18, 2020.