Stilestrongylus azarai

Stilestrongylus azarai	Contents	Rev: 04/10/2026
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Stilestrongylus Menu	Economic Importance	Ecosystem Functions and Services
	Distribution	Management
Return to Heligmonellidae Menu	Feeding	References
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Classification:

Chromadorea
Chromadoria

Rhabditida
Rhabditina
Infraorder Rhabditomorpha
Heligmosomoidea: Helligmonellidae
Nippostyrongylinae
Stilestrongylus azarai (Durette-Desset & Sutton, 1985), Digiano & Serrano, 2024

Synonyms:

Stilestrongylus oryzomysi Sutton & Durette-Desset, 1991

Morphology and Anatomy:

Worms small to medium-sized, loosely to tightly coiled, usually with 2-3 spires in anterior portion of body.
Head rounded, buccal opening surrounded by thin ring; 2 amphids;4 outer labial, and 4 cephalic papillae visible
Synlophe with 25 subequal ridges in both sexes. Double axis of orientation of ridges: right axis inclined at 60 degrees to sagittal
axis, left axis at 80 degrees. Twelve dorsal and 13 ventral ridges with respect to axis of orientation

Females:

Reproductive tract monodelphic. Uterus less than 20% of body length; .
Infundibulum slightly longer than vestibule.
Eggs few in uterus (3-9)
Slight cuticular inflation from level of distal uterus up to vulvar aperture.
Posterior extremity straight or barely curved. Tail short and stout, ending in mucron Posterior end moderately retractile.

Ref: Digiania and Serrano, 2024

Males:

Bursa large, bellshaped, asymmetrical, dorsal lobe well developed and right lobe markedly larger than left.
Prebursal papillae absent.
Bursa with 2 ventral papillae close to each other. Right
lobe pattern of type 1-4, with ray 2 arising
first from long common trunk of rays 3-6. (see greater detail in original description). Left lobe pattern of type 2-2-1. Rays 2 and 3 diverging in a V-shape. Short common trunk of rays 4-6, with rays 3 and 6 diverging at same level; rays 4 and 5 diverging last.
Genital cone long, well developed, bulbous at base, strongly curved ventrally in distal part. Distal half of cone with sclerotized walls; dorsal lip with two rounded conspicuous papillae; ventral lip with single lappet-shaped papilla..
Spicules thin and alate, ending in single sharp tip.
Gubernaculum conspicuous.

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

Distribution:

Originally desribed from Akadon azarae (Azara's grass mouse) from Buenos Aires province, Argentina.

Biology and Ecology:

An intestinal parasites of Akodon azarae (Cricetidae).

Life Cycle:

Ecophysiological Parameters:

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

Ecosystem Functions and Services:

Digiani, M.C., Serrano, P.C. 2024. Synonymy, redescription, molecular characterisation, and new distribution data of species of Stilestrongylus and Guerrerostrongylus (Nematoda, Heligmonellidae) parasitic in sigmodontine rodents from Argentina and Uruguay: a collection-based survey. Zoosyst. Evol. 100 (4) 2024, 1315-1331 | DOI 10.3897/zse.100.125466

Durette-Desset, M-C., Sutton, C.A. 1985. Contribucion al conocimiento de la fauna parasitolÃ³gica argentina X, Nematodes (Trichostrongyloidea) en Akodon azarae azarae (Fischer) y Reithrodon auritus Fischer. Revista del Museo de La Plata 14: 21-33.

Sutton, C.A., Durette-Desset, M-C. 1991. Nippostrongylinae (Nematoda: Trichostrongyloidea) parasites dâ€™Oryzomys flavescens en Argentine et en Uruguay. Revue Suisse de Zoologie 98: 535-553. https://doi.org/10.5962/bhl.part.82072