Thonus		Contents		Rev 03/14/2023
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Thonus Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Dorylaimidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Note: Although Thonus is considered a synonym of Crassolobium and, based on dates of publication, would be the junior synonym, Pena-Santiago and Ciobanu (2007) suggest a reversal of the precedence condition because (i):the name Thonus identifies a highly diversified taxon (more than 40 species are currently named with this generic substantive while Crassolabium is a poorly known and seldom used name, with only two species; (ii) Thonus is a name that identifies a worldwide-distributed taxon, recorded in many (50) bibliographic references on taxonomical, faunistical and ecological subjects, whereas by contrast only a few (10) references are available on Crassolabium, mostly discussing its taxonomy and status; (iii) Thonus is a name that identifies a rather well-defined morphological pattern among dorylaimid nematodes, and relevant morphological (and also biogeographical and ecological information) is associated with it, obviously, that is not at all the case of Crassolabium; (iv) the etymology of Crassolabium, meaning thick or fat lip, refers to a peculiar morphological feature that does not fit the Thonus pattern and whose taxonomical value has been demonstrated to be of minor significance and interest.

However, despite those arguments, Pena-Santiago and Alvarez-Ortega (2014) listed Thonus as a junior synonym of Crassolobium!  In the same paper, the rounded tail members of the subfamily Qudsianematinae of the family Qudsianematidae were transferred to a new subfamily (Labronematinae) of the family Dorylaimidae.  In his recent book, Dorylaimida Mundi (Nematoda) 2021, Pena-Santiago, ever and appropriately an advocate for the Rules of Zoological Nomenclature, listed the current species of Thonus under the genus name Crassolobium.

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Morphology and Anatomy:

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Distribution:

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Feeding:

  Designated omnivore-predator by Yeates et al (1993).     

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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. and Ciobanu, M. 2007. On the Identity of the Genus Crassolabium Yeates, 1967 (Dorylaimida: Qudsianematidae). J. Nematology 39:231-236.

Pena-Santiago, R. and S. Alvarez-Ortega. 2014. An integrative approach to assess the phylogeny and the systematics of rounded-tailed genera of the subfamily Qudsianematinae (Nematoda, Dorylaimida). Zoologica Scripta 43:418-428.

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: March 14, 2023.