Tylocephalus auriculatus




Rev: 01/11/2022

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       Tylocephalus auriculatus (Butschli, 1873) Anderson, 1966


Plectus auriculatus Butschli, 1873

Wilsonema auriculatum (Butschli, 1873) Cobb, 1913

Tylocephalus bacillivorus Crossman, 1933

Wilsonema bacillivorus (Crossman, 1933) Chitwood & Chitwood, 1950


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Morphology and Anatomy:

  • Cuticle thin, annulated.
  • Lateral field 4.5-5.5 um wide at midbody;, consisting of two separate wings divided by striated cuticle, fading anteriorly at level of pharyngeal corpus and ending near tail terminus.
  • Deirid setiform, at level of excretory pore, inside lateral field.
  • Pharyngeal region with 11-14 somatic setae; body remainder with 13- 17 somatic setae
  • Anterior end with pronounced bilateral and dorsoventral symmetry; Cervical cuticular expansions with 9-13 annules, extending backward to the level of the four postcephalic setae
  • Cornua flattened, leaf-shaped with finely rounded terminus,
  •  Subdorsal and subventral lip pairs modified into two median ridges, each with a pair of submedian flaps of cuticle, projecting forward and inward.
  •  Lateral lips modified, bearing two sublateral cuticular plates shaped like large quadrants. Lateral lips midlaterally extending in between quadrants, each forming a tapering tip, containing a nerve ending.
  • Amphidial aperture 2 um wide, circular, located at about half of stoma length.
  • Stoma plectoid.
  • Pharyngeal corpus cylindrical, plump,  Isthmus plump, surrounded by nerve ring at its anterior end and by renette cell at its posterior end.
  • Basal pharyngeal bulb oval, with valves.
  • Cardia embedded in intestinal tissue.
  • Excretory gland duct weakly cuticularised, enveloped by renette cell. Excretory pore posterior to nerve ring.
  • Reproductive system didelphic, amphidelphic, ovary branches reflexed.
  •  Vulva equatorial, transverse. Vagina short, encircled by a single sphincter muscle. Epiptygmata absent.
  • Rectum short and stout.
  • Tail gradually narrowing, arcuate ventral, with five caudal setae
  •  Caudal glands and spinneret present.
Tylocephalus auriculatus
A,C.D.F,G: Male posterior; E: Spicules; B: Male testis; H: anterior region.
from Holovochov et al., 2004


  • Similar to female except  pharyngeal region with 14-15 somatic setae and remainder of body with 27-32 somatic setae
  • Cervical cuticular expansions with 7-9 annules.
  • Diorchic, testes opposed and poorly developed.
  • Gubernaculum absent.
  • Tail with 9-14 caudal setae  The posteriormost seta (spur) is always located left subdorsal.
  Ref: Holovachov et al., 2004

Labial region components of Tylocephalus

from Holovachov et al., 2003.

CE = cervical expansion, CORN = cornu; FLAB = flabellum; LR = lateral rim; MP = midlateral projection; MR = median ridge; QUAD = quadrant; RR = radial ridge; YI = Y-shaped incisure.

For comparisons among genera, go to subfamily Tylocephalustinae

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:


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Reported Ukraine, Russia, Greece. Often in dry, sandy areas.

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Bacterial feeding

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Biology and Ecology :

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Life Cycle:


Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters

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Ecosystem Functions and Services :

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Holovachov, O., Bostrom, S., Mundo-Ocampo, M. 2004. Description of three known and two new species of the genus Tylocephalus Crossman, 1933 with a revised taxonomy of the genus and key to species of the subfamily  Wilsonema (Plectida). Russian J. Nematol 12:115-130.

Wood, F.H. 1973. Nematode feeding relationships: Feeding relationships of soil-dwelling nematodes. Soil Riol. Biochem. 5: 593-601.

Copyright © 1999 by Howard Ferris.
Revised: January 11, 2022.