Auanema freiburgense		Contents		Rev 07/02/2023
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Auanema Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Rhabditidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Chromadorea

  Rhabditia

    Rhabditida

      Rhabditoidea

        Rhabditidae

Rhabditinae

Synonyms

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Morphology and Anatomy:

• Cuticle with fine annulation. Lateral field inconspicuous, only weakly separated from the other part of body surface by lack of annules, ridges (alae) absent.
• Lip region not clearly offset from body contour, with six equal-sized sectors, two dorsal sectors, right lateral and subventral sectors and left lateral and subventral sectors form a triangular stomatal opening.
• Each lip with a setiform labial sensillum.
• Four setiform cephalic sensilla.
• Amphids oval-shaped pores at the level of the posterior end of cheilostom.
• Stoma cylindrical, about 7x longer than wide, with cheilostom, gymnostom and stegostom. Cheilostom and gymnostom simple cylinder; Pro- and meso-stegostom simple cylinder, comprising a little more than half of the stomatal tube (form pharyngeal sleeve); meta-stegostom slightly anisotopic and isomorphic with one small denticle on each sector.
•  Procorpus cylindrical; metacorpus a well-developed median bulb, isthmus slender, basal bulb rounded (not polygonal) with weak duplex haustrulum posterior to valves.
•  Cardia conspicuous.
• Nerve ring surrounding the posterior part of isthmus.
• Excretory pore conspicuous .Excretory tube extends anteriorly, and then reflexes to continue posterior. An excretory cell is located a little posterior to the excretory pore opening.
• Deirid at the same level as excretory pore.

Female and Hermaphrodite:

• Females and hermaphrodites morphologically indistinguishable.
• Vulva a hotizontal slit mid body; cuticle around the vulva lacks annulations.
• Didelphic, amphidelphis, gonads dorsally reflexed
• Germ cells arranged in two to three rows in distal half, well-developed oocytes arranged in a single row;
•  Oviduct connecting ovary (ovotestis) and spermatheca, formed by small rounded cells. Spermatheca and uterus with thick wall.
• Vagina perpendicular to body surface, with thick wall, constricted by sphincter muscle at the vagina-uterus junction.
•  Young females/hermaphrodites carry usually none or only one embryo in each uterus, older individuals, often more than 10 well-developed embryos are present in an expanded uterus.
• Two subventral and one dorsal rectal glands surrounding intestine-rectum junction and anterior part of rectum.
• Rectum as long or slightly longer than anal body diam.
• Anal opening a horizontal slit; posterior anal lip expands slightly in lateral view.
• Tail smoothly tapered to finely elongated conical tip but not filiform.

Males:

• Monorchic, testis on right of intestine;
• Two subventral and one dorsal cloacal (anal) glands visible at the level of anterior end of retracted spicules.
• Spicules with rounded manubrium, paired, forming a V� shape in ventral view; smoothly arcuate in lateral view.
•  Gubernaculum short, narrow.
• Bursa open peloderan, with smooth edges, covering the whole tail region.
• Eight pairs of genital papillae arranged as <GP1, GP2, (GP3, CO), GP4, GP5d, GP6, (GP7d, GP8)>, where the distance between GP1-GP2 is large.Two pairs of GP are located precloacally, one pair adcloacally. Tips of GP5 and GP 7 attached to the dorsal side of bursa, all other GPs are attached ventrally.
• Papilliform phasmids with ventral openings in a terminal position near the tail tip.

Dauer Juveniles:

• Anterior end dome-shaped, continuous with body contour.
• Amphids oval-shaped pore, conspicuous, at the level of the posterior end of cheilostom.
• Initially ensheathed in coarsely annulated J2 cuticle as a protective tube; J2 cuticle is attached to substrate when dauer juvenile nictates.
• Stoma narrow, cylindrical, weakly sclerotized, anterior end closed;
• Procorpus narrow, not well-developed. Metacorpus a weak median bulb. Isthmus, slender. Basal bulb with duplex haustrulum posterior to valves,
•  Excretory pore opening and tube similar to that of female.
•  Tail conical with bluntly pointed tip

Ref: Kanzaki et al., 2017

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Distribution:

Auanema freiburgense was originally isolated from a dung pile (mostly horse dung) in Freiburg, Germany in August 2003 by Dr. Walter Sudhaus.

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Feeding:

  Bacterial feeding.

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Biology and Ecology:

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Life Cycle:

Life Cycle:

In A. rhodense, the three sexual morphs are produced by selfing hermaphrodites and crossing females, independently of the environmental conditions (Chaudhuri et al., 2015).  However, in A. freiburgense, mothers exposed to crowding cues derived from high population densities produce mostly hermaphrodite offspring. In the absence of those crowding cues, mothers produce predominantly females and a few males (Tandonnet et al., 2020, Zuco et al., 2018).

Ecophysiological Parameters:

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Ecosystem Functions and Services:

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Management:

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References:

Chaudhuri J., Bose N., Tandonnet S., Adams S., Zuco G., Kache V., Parihar M., von Reuss S. H., Schroeder F. C., Pires-daSilva. 2015.  A.. Mating dynamics in a nematode with three sexes and its evolutionary implications. Scientific Reports. 5:17676.

Kanzaki, K., Kiontke, K., Tanaka, R., Hirooka, Y., Schwarz, A., Muller-Reichert, T., Chaudhuri, J., Pires-daSilva, A. 2017. Description of two three-gendered nematode species in the new genus Auanema (Rhabditina) that are models for reproductive mode evolution. Nature Scientific Reports 7:11135

Tandonnet, S., Haq, M., Turner, A., Grana, T., Paganopoulou, P., Adams, S., Dhawan, S., Kanzaki, N., Felix, M-A., Pires-daSilva, A. 2022. De novo Genome Assembly of Auanema melissensis, a Trioecious Free-Living Nematode. J. Nematology 54: | DOI: 10.2478/jofnem-2022-0059

Zuco G., Kache V., Robles P., Chaudhuri J., Hill B., Bateson C., Pires da Silva A.. 2018. Sensory neurons control heritable adaptation to stress through germline reprogramming. bioRxiv, 406033 

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Copyright  1999 by Howard Ferris.
Revised: July 02, 2023.

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