Panagrellus Thorne, 1938

Type species of the genus Panagrellus pycnus Thorne, 1938

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Morphology and Anatomy:

The main morphological charachters useful for separating species of Panagrellus are the shape of the spicules and, sometimes, the form of the vulva (Hechler, 1971).

General characteristics of the genus:

• Cuticle with extremely shallow transverse stria
• Lateral fields with four deeper longitudinal striations at midbody
•  Head continuous with or only slightly offset from body and with six slightly separated lips.
• Cheilostom  hexagonal in cross section, lining not sclerotized. Prostom partially surrounded with esophageal collar, lining sclerotized, thicker posteriorly.
• Stoma triangular behind prostom, dorsal wall slightly protruding with a small central wart.
• Three narrow dorsal teeth just behind wart, two pairs subventral teeth posterior to dorsal teeth.
• Procorpus 55 to 65% of esophageal length, nerve ring just anterior to basal bulb,
• Excretory pore between nerve ring and anterior limits of isthmus
• Female mondelphic-prodelphic
• Vulva and anus in females transverse slits, slightly curved anteriorly. Vagina shape varying between species.
• Female tails elongate-conical .
• Male tail tapering to slightly offset flagellum.
•  Posterior end of males with seven pairs of papillae: (i) subventral just anterior to spicule manubrium; (ii) subventral adanal; (iii) lateral adanal; (iv, v) two closely approximated subventral pairs midway between anus and beginning of tail flagellum; (vi) subdorsal, position variable within species, behind anus; (vii) subdorsal just anterior to tail flagellum. the the position of each pair of papillae may vary considerably within a species,.
•  Phasmids obscure, located at 45 to 50%, rarely as far forward as 35%, of tail length in females; opposite posterior subdorsal papillae in males.
• Spicules differing among species. Detailed descriptions in Hechler (1971).

Ref: Hechler, 1971

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Distribution:

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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:

Ferris, H. 2009. The beer mat nematode: A study of the connectedness of scientific discovery. Journal of Nematode Morphology and Systematics 12:19-25.

Hechler, H.C. 1971. Taxonomic Notes on Four Species of Panagrellus Thorne (Nematoda: Cephalobidae). J. Nematology 3:227-237.

Stock, S.P., Nadler, S.A. 2006. Morphological and molecular characterisation of Panagrellus spp. (Cephalobina: Panagrolaimidae): taxonomic status and phylogenetic relationships. Nematology 8:921-938.

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Copyright © 1999 by Howard Ferris.
Revised: December 17, 2024 .