Rev: 11/21/2023

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
Return to Leptonemella Menu Ecosystem Functions and Services
Distribution Management
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  •         Leptonemella Cobb, 1920


    Type species:  Leptonemella cincta Cobb, 1920

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    Morphology and Anatomy:


    • Cuticle with fine but distinct striation.

    • Head capsule convex, surface smooth or punctuated, well demarcated from annulated body cuticle.

    •  Amphidial fovea latero-subterminal, small, spirally coiled in 1.5 turns, loop-shaped or formed as a shepherd’s crook,.

    • Pharynx very slightly swollen anteriorly. 

    • Tail elongateconical.


    • Didelphic, ovaries antidromously reflexed, both genital branches to the left of intestine.



    • Monorchic,

    • Gubernaculum with or without dorsocaudal apophysis.

    • Males of some species with stout postcervical, preanal, and postanal subventral setae.


    Ref: Armenteros et al., 2014

    Body size range for the species of this genus in the database - Click:
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    Marine nematodes in tidal sands and coral reefs.

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    Nematodes in the subfamily Stilbonematinae of the Desmodoridae are associated with, and feed on,  dense coatings of sulfur-oxidizing chemoautotrophic gammaproteobacteria with which they are apparently obligately symbiotic. The nematodes inhabit environments with low oxygen availability and reducing conditions. Essentially, the nematodes "farm" their bacterial associates by migrating to ocean sediments rich in hydrogen sulfide (Bulgheresi Reference Bulgheresi2011; Murfin et al. Reference Murfin, Dillman, Foster, Bulgheresi, Slatko, Sternberg and Goodrich-Blair2012; Blaxter and Koutsovoulos, 2015).

    The symbiotic bacteria are coccoid to short stick-shaped



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    Biology and Ecology:


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    Life Cycle:

    For Ecophysiological Parameters for this genus, click 
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    Ecosystem Functions and Services:


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    Armenteros, M., Ruiz-Abierno, A., Decraemer, W. 2014. Taxonomy of Stilbonematinae (Nematoda: Desmodoridae): description of two new and three known species and phylogenetic relationships within the family. Zool; J. of the Linnean Soc. 171-1-21.

    Blaxter, M. and Koutsovoulos, G. 2015. The evolution of parasitism in Nematoda. Parasitology 142: S26-S39.

    Bulgheresi, S. 2011. Calling the roll on Laxus oneistus immune defense molecules. Symbiosis 55, 127-135.

    Chitwood, B.G. 1936. Some marine nematodes from North Carolina. Proc. Helmint. Soc. Wash. 3: 1-16.

    Murfin, K. E., Dillman, A. R., Foster, J. M., Bulgheresi, S., Slatko, B. E., Sternberg, P. W. and Goodrich-Blair, H. 2012. Nematode-bacterium symbioses - cooperation and conflict revealed in the “omics” age. Biological Bulletin 223, 85-102.


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    Copyright © 1999 by Howard Ferris.
    Revised: November 21, 2023.