Metaxonchium		Contents		Rev 04/03/2023
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Metaxonchium Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Belondiridae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

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Morphology and Anatomy:

Metaxonchium resembles the genera Axonchium, Dactyluraxonchium Coomans & Nair, 1975 and Syncheilaxonchium Coomans & Nair, 1975, but differs from them in having well-developed pars refringens vaginae, which are absent in the other genera. The genus is relatively homogeneous taxon, mainly characterized by having separate lips with the lip region offset by a constriction, the odontostyle short and fusiform, pharyngeal sections separated by an isthmus-like narrowing, pars refringens vaginae well developed, caudal region short and rounded to convex conoid in both sexes, and evenly-spaced ventromedian supplements in the male.

• Medium to large-sized nematodes, body 1.6 to 4.2 mm long.
•  Cuticle two- or three-layered, with fine transverse striation; thicker in caudal region.
• Lip region offset by constriction, lips separate.
• Amphid openings large, encircling most of the base of the lip region base.
• Odontostyle fusiform, 8 to 23 um long or about equal to lip region diameter.
• Guiding ring simple, visibly refractive.
• Odontophore rod-like, simple.
• Anterior slender and posterior enlarged regions of esophagus separated by a narrower isthmus region.
• Basal expansion of esophagus occupying up to three-fourths of total esophagus length.
• Cardia tongue-like, well developed.
• Female genital system mono-opisthodelphic, with anterior branch reduced to a uterine sac with a vestigial terminal cell mass, posterior uterus long and often tripartite with apophyses in several species.
• Pars refringens vaginae well-developed; vulva a transverse slit.
• Tail similar in both sexes, short and rounded to convex conoid.
• Males often frequent, with variably sized and shaped spicules, and 7 to 17 spaced ventromedian supplements (but 19 to 30 contiguous in two species), with or without hiatus in spacing anterior to cloaca..

Ref: Pena-Santiago et al (2014)

Metaxonchium persicum - anterior	M. persicum - isthmus-like narrowing in esophagusr	M. persicum - tongue-shaped cardia
Drawings from Pena-Santiago et al (2014)
Body size range for the species of this genus in the database - Click:

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Distribution:

Species of the genus reported from various areas of the world, many from USA and Europe but also South Africa, India, Iran, Japan and South Korea, Costa Rica and New Zealand.

 Pena-Santiago et al. (2014), who listed a  25 valid species (Varela Banavides andf Pena-Santiago, 2017.,

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Feeding:

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Biology and Ecology:

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Life Cycle:

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Ecosystem Functions and Services:

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Management:

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References:

Pena-Santiago, R., Niknam, G. Alvarez-Ortega, S., Jabbari, H. 2014. Metaxonchium persicum sp. n. from Iran (Nematoda, Dorylaimida, Belondiridae), with an updated taxonomy of the genus. Zootaxa 3785 (4): 501-517 .

Varela-Benavides, I. & Pena-Santiago, R. (2017) Metaxonchium toroense n. sp. (Nematoda, Dorylaimida, Belondiridae) from Costa Rica, with the first molecular study of a representative of the genus. Journal of Helminthology. https://doi.org/10.1017/S0022149X17001134

Yeates, G.W., T. Bongers, R. G. M. De Goede, D. W. Freckman, and S. S. Georgieva. 1993. Feeding habits in soil nematode families and genera—An outline for soil ecologists. Journal of Nematology 25:315-331

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Copyright  1999 by Howard Ferris.
Revised: April 03, 2023.