Family Selachonematidae

Revised 09/06/24

Nematoda

Chromadorea

Chromadoria

Chromadorida

Chromadorina

Chromadoroidea

Selachinematidae Cobb, 1915

Two subfamilies: Choniolaiminae Schuurmans-Stekhoven & Adam, 1931 and Selachinematinae Cobb, 1915

A family of marine nematodes.

Choniolaiminae: Buccal cavity spacious, divided into two compartments, anterior portion broad, posterior narrow; reinforced by cuticularised rhabdions in both portions. Mandibles absent.

Selachinematinae: Buccal cavity spacious, divided into two compartments, with posterior rhabdions modified into protrusible denticulate mandibles

Ref:  Leduc, 2013; Leduc and Zhao, 2016; Tchesunovet al., 2020.

 

Females: didelphic-amphidelphic, ovaries reflexed

Males: Usually two outstretched testes, either on same or different sides of the intestine; pre-cloacal supplements usually present, usually cup-shaped, sometimes setose, papilliform, rarely tubular.

 

Species of Selachinematidae are specialised predators feeding on other nematodes – or at least on other large-sized items. Ingestion of prey nematodes by selachinematid species has been documented (Allgén, 1939; Jensen, 1987; Okhlopkov, 2003).

Usually, the quota of predatory nematode species is higher in coarse-grained sediments and thus the role of selachinematids as regulators of community structure may be more significant in in sandy sediments (Warwick, 1971; Kennedy, 1994)

 

 References:

Allgen, C.A. 1939. Räuberische Ernährungsweise mariner Nematoden, insbesondere Halichoanolaimini. Folia Zoologica et Hydrobiologica 9, 321-32

Bongers, T. De Nematoden van Nederland.

Goodey, T and J.B. Goodey, 1963. Soil and Freshwater Nematodes. Methuen. London

Jensen, P. 1987. Feeding ecology of free-living aquatic nematodes. Marine Ecology Progress Series 35, 187-196.

Kennedy, A.D. 1`994.. Predation within meiofaunal commnities: description and results of a rapid-freezing method of investigation. Marine Ecology Progress Series 114, 71-79.

Leduc, D.  2013. Two new genera and five new species of Selachinematidae (Nematoda, Chromadorida) from the continental slope of New Zealand.  European Journal of Taxonomy 63: 1-32.

Leduc, D., Zhao, Z.Q. 2016. Molecular characterisation of five nematode species (Chromadorida, Selachinematidae) from shelf and upper slope sediments off New Zealand, with description of three new species. Zootaxa 4132:59-76.

Neira, C., Decraemer, W. 2009. Desmotersia levinae, a new genus and new species of free-living nematode from bathyal oxygen minimum zone sediments off Callao, Peru, with discussion on the classification of the genus Richtersia (Chromadorida: Selachinematidae. Organisms, Diversity and Evo;ution 9, 1:e1-1.e15

Okhlopkov, J.R. 2003. [Feeding of free-living nematodes of the families Selachinematidae and Richtersiidae in the White Sea.] Proceedings of the Pertsov White Sea Biological Station 9, 127-139.

Tchesunov, A., Jeong, R. Lee W. 2020.  Two New Marine Free-Living Nematodes from Jeju Island Together with a Review of the Genus Gammanema Cobb 1920 (Nematoda, Chromadorida, Selachinematidae). Diversity 2020, 12, 19; doi:10.3390/d12010019.

Warwick, R.M. 1971. Nematode associations in the Exe estuary. Journal of the Marine Biological Association of the United Kingdom 51, 439-454

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