Revised 03/25/25
Chromadoria
Desmodoroidea
Stilbonematinae
Described as subfamily Stilbonematinae of the Desmodoridae by Chitwood, 1936. Not clear when (or if) it became a family; probably retain as subfamily.
A small subfamily of free-living marine nematodes.
Associated with, and feeding on, dense coatings of sulfur-oxidizing chemoautotrophic bacteria with which they are apparently obligately symbiotic. The coating of bacteria gives the nematodes a white appearance, while the nematodes themselves are usually colourless.
The nematodes may inhabit environments with low oxygen availability and reducing conditions. However, in marine shallow-water, porous sediments, members of the subfamily Stilbonematinae may be found in high numbers. (Scharhauser et al., 2025)
Nematodes in the Stilbonematinae)associate with gammaproteobacteria that grow as a lawn on the cuticle of the nematode. These sulfur-fixing bacteria are a major food source for the nematode. Essentially, the nematodes ‘farm’ their bacterial associates by migrating to ocean sediments rich in hydrogen sulfide (Bulgheresi 2011; Murfin et al. 2012; Blaxter and Koutsovoulos, 2015).
References:
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.
Scharhauser, F. et al. 2025. Revision of the genus Robbea (Stilbonematinae: Desmodoridae), worldwide abundant marine nematodes with chromophoric Fe–Br inclusions and the description of a new stilbonematine genus, Zoological Journal of the Linnean Society, 203, Issue 1, January 2025, zlae005, https://doi.org/10.1093/zoolinnean/zlae005
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