Family Desmodoridae

Revised 01/05/24






Desmodoridae Filipjex, 1922

   A family of free-living marine nematodes.

The family Desmodoridae is a diverse and widely distributed family of free-living marine nematodes. There is a large number of species, of which  very few have been described. Most species have been described from shallow water marine habitats. However, ecological studies on marine nematodes record nematodes of the Desmodoridae in deep-sea sediments, usually in low numbers, with their relative abundance reaching a maximum of 1% of the total mass (Soetaert and Heip, 1995).

The deep sea is the largest, the least known and one of the least studied environments on the planet. It contains extremely large habitats, and millions of square kilometers of continental slopes and abyssal plains. Frequently, more than 90% of the species collected in a typical abyssal sediment sample are new to science. The species richness of such assemblages often exceeds expectations.  Because of the diversity and abundance, it is difficult to select enough specimens of the same species for species descriptions:. Although there may be several hundred unknown species in a single sample of 1000 nematodes, most of the species present  may be represented by only one or a few specimens (Moura et al., 2014).


Desmodorella sp (family Desmodoridae)
Head end with spiral amphid and hair-like setae
(from Cesaroni et al., 2017)


Six Subfamilies: Desmodorinae, Spiriniinae, Stilbonematinae, Pseudonchinae, Molgolaiminae and Prodesmodorinae

Subfamily Desmodorinae Filipjev, 1922:

Subfamily Spiriniinae Chitwood, 1936:

Ref: Cavalcanti et al., 2009; Leduc and Zhao, 2016.

Subfamily Stilbonematinae Chitwood, 1936:

Subfamily Prodesmodorinae Lorenzen, 1981

Leduc and Zhae 2016 proposed that this subfamily be removed from the Desmodoridae because it includes terrestrial and freshwater nematodes.

Subfamily Molgolaiminae: Jensen, 1978

Subfamily Pseudonchinae: Gerlach & Riemann, 1973


An interesting feature of the family Desmodoridae is the sexual dimorphism of the amphids. In some species the amphid shape may extend longitudinally in males while in females it is a spiral.. Sexual dimorphism of amphids has been observed in several genera of marine Desmodoridae, including Onyx Cobb, 1891; Pseudochromadora Daday, 1899; Chromaspirina Filipjev, 1918; Croconema Cobb, 1920; Leptonemella Cobb, 1920; Zalonema Cobb, 1922; Spirinia Gerlach, 1963; Echinodesmodora Blome, 1982; and Psammonema Verschelde & Vincx, 1995 (Moura et al., 2014).


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.

Cavalcanti, M.D.F., Da Silva, M.C., Da Fonseca-Genevois, 2009. Spirodesma magdae nov. gen. nov. sp. (Nematoda: Desmodoridae) from the Brazilian deep sea (Campos Basin, Rio de Janeiro, Brazil). Zootaxa 2096: 109118.

Cesaroni, L. Guidi, L., Balsamo, M., Semprucci, F. 2017. Scanning electron microscopy in the taxonomical study of free-living marine nematodes. Microscopie 28:6970

Gharahkhani, A., Pourjam, E., Leduc, D., Pedram, M. 2021. Further data on Iranian marine nematode diversity, with description of three new Desmodoridae Filipjev, 1922 (Nematoda: Desmodorida) species from the Persian Gulf. Nematology 23:781-802.

Leduc, D., Zhao, Z. 2016. Phylogenetic relationships within the superfamily Desmodoroidea (Nematoda: Desmodorida), with descriptions of two new and one known species. Zoological Journal of the Linnean Society, 176: 511536.

Moura, J.D.R., Da Silva, M.C., Esteves, A.M. 2014. Four new species of Desmodora (Nematoda) from the deep south-east Atlantic, and a case of intersexuality in Desmodoridae. J. Mar. Biol. Associ. UK. 94:85-104.

Soetaert, K. and Heip, C.H.R. 1995. Nematode Assemblages of Deep-Sea and Shelf Break Sites in the North-Atlantic and Mediterranean-Sea. Marine Ecol. Progress Series 125:171-183.

Tchesunov. A.V. 2013. 7.13 Order Desmodorida de Coninck, 1965 In Schmidt-Rheas and de Gruyter, W. Handbook of Zoology.Gastrocticha, Cycloneuralia, Gnatifera. Volume 2: Nematoda


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