Tricirronema		Contents		Rev 11/24/2021
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Tricirronema menu				Ecosystem Functions and Services
		Distribution		Management
Return to Bicirronematidae menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

      Chromadorea
        Rhabditida
         Rhabditia
          Bicirronematidae

                Tricirronema Siddiqi, 1993

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Morphology and Anatomy:

• Body arcuate ventrad, almost cylindrical anterior to anus.
• Cuticle striated, annuli smooth.
•  Lateral field with 3 incisures begins just anterior to nerve ring, terminates somewhat posterior to the level of phasmid in females and at base of terminal tail mucro in males.
• Lip region weakly offset, with six globular lips arranged in three pairs: one dorsal and two subventral. Pairs of lips separated by primary axils with two long irregularly branching cirri in each axil.
•  Cephalic and labial probolae absent. Six outer labial and four cephalic papilliform sensilla, located near anterior margin of lips.
•  Amphid apertures small, oval, located on lateral lips.
• Stoma divided into cheilostom, gymnostom and stegostom. Cheilostom wide, barrel-shaped; cheilorhabdia strongly sclerotized, bar-shaped in median section. Gymnostom short and as wide as cheilostom, gymnorhabdia strongly sclerotized. Stegostom comprises the remaining part of stoma, enveloped by pharyngeal muscular tissue, clearly subdivided into funnel-shaped prostegostom, and mesostom, metastom and telostegostom with rectangular rhabdia.
• Metastegostomatal denticle absent.
• Dorsal gland orifice inserted between meta- and telostegorhabdia.
• Pharynx cephaloboid. Pharyngeal procorpus and metacorpus cylindrical.
•  Isthmus narrower than metacorpus and delineated from it by a discontinuity in muscular tissue and by orifices of subventral pharyngeal glands.
• Basal pharyngeal bulb oval, with strongly developed valves.
• Cardia distinct, enveloped by intestinal tissue.
• Nerve ring encircling metacorpus.
• Hemizonid present, just anterior to excretory pore.
• Secretory-excretory gland cell located dorsally on lefthand side at level of isthmus. Excretory pore opens at level of or posterior to nerve ring.
• Deirid located posterior to excretory pore, inside lateral field.

Female:

•  Reproductive system monodelphic, prodelphic; ovary branch antidromously reflexed, on righthand side of intestine (dextral). Posterior part of ovary straight.
• Spermatheca offset, projecting anteriorly between oviduct and uterus, filled with round spermatozoa.
• Strong sphincter between uterus and ovijector.
• Vulval lips slightly protruding.
• Postvulval uterine sac (PUS) well developed.
• Vagina straight or sigmoid, encircled by single sphincter muscle in its proximal part.
• Rectum very long, its proximal part surrounded by three gland-like cells.
• Phasmids at level of or just posterior to anal opening.
• Tail conoid, arcuate ventrad, tail tip with harpoon-shaped or ragged mucro.

Male:

• Reproductive system monorchic; testis on right-hand side of intestine (dextral), reflexed ventrally anteriorly.
• Spicules cephaloboid, with ventral velum.
• Gubernaculum arcuate, wedge-shaped; cornua crurum absent.
• Tail conoid, arcuate ventrad, tail tip with harpoonshaped mucro.
• 16 paired male genital papillae, arranged as follows: two ventrosublateral pairs anterior to cloaca; one subventral and one ventrosublateral pair at one-third of tail length, anterior to phasmids; one dorsosublateral pair just posterior to middle of tail; two subventral and one subdorsal pair near tail terminus.
• A prominent midventral papilla somewhat anterior to cloacal opening.
• Phasmids located just posterior to the ventrosublateral caudal papillae.

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Distribution:

Species have been described from tropical Africa, Vietnam and Cost Rica.

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Feeding:

Bacterial feeder.

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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:

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Copyright © 1999 by Howard Ferris.
Revised: November 24, 2021 .