Scutellonema

 

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Rev 03/16/2021

Spiral Nematodes Classification Hosts
Morphology and Anatomy Life Cycle
Return to Scutellonema Menu Economic Importance Damage
Distribution Management
Return to Hoplolaimidae Menu Feeding  References
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 Classification:

          Tylenchina
         Tylenchoidea
          Hoplolaimidae
           Hoplolaiminae

           Scutellonema (Steiner, 1937) Andrassy, 1958

Spiral Nematodes

    Synonyms:
      None.

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Morphology and Anatomy:

Nematodes of the genus Scutellonema are characterized by scutella (enlarged phasmids) in the lateral fields.  The scutella are opposed (at the same location on either side of the body) and are located close to the level of the near the anus.

As of 2017, the genus contained more than 50 species (Kolombia et al., 2017).

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 Female: Body spiral to C-shaped or almost straight.  

Labial region narrow truncate to offset rounded; annulated, with or without longitudinal striae.  First labial annule divided into six sectors, lateral sectors smaller than the others (SEM). 

Amphid apertures oval between labial disc and lateral sectors.  

Lateral field with four lines usually areolated near phasmids (scutella) and anteriorly, sometimes transverse striae scattered over whole field.  

Labial framework, stylet, and stylet knobs average-sized for the family; knobs rounded to indented.  

Dorsal esophageal gland opening 4 to 8 µm from stylet base.  

Esophageal gland overlap dorsal and lateral.  

Two genital branches outstretched, equally developed.  

Epiptygma present.  

Tail short, rounded.

Phasmids enlarged, 3-4 um in diameter, just pre-anal. The term "scutellum" refers to Latin "shield" for shape and size of phasmids - hence Scutellonema.

 

 

 

A recent key to the species of Scutellonema is provided by Kolombia et al., 2017
Males: Caudal alae enveloping tail tip, regular or, rarely, deeply lobed.  

No secondary sexual dimorphism.

[Ref: Fortuner,  (1987), and H. Ferris.]

Examples of scutella in lateral field of Scutellonema clavicaudatum

(Drawings from Van den Berg et al., 2017)
Body size range for the species of this genus in the database - Click:
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Distribution:

Species of Scutellonema are widely distributed in tropical and subtropical regions with the greatest number of species recorded from Africa (van den Berg et al., 2017); approximately 60% of described species are from that continent..

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Economic Importance:

D-rated pests in California.

 Three species, the yam nematode S. bradys, S. cavenessi, and the Carolina spiral nematode S. brachyurum are reported as agricultural pests.  Other species are parasites of non-agricultural plants or are unknown to cause economic damage to crops (Van den Berg et al., 2017).

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Feeding:
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Hosts:
For an extensive host range list for this genus, click
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Life Cycle:

For Ecophysiological Parameters for this genus, click 

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Damage:

 

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Management:

 

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References:

Fortuner, Rev. Nematol. 10(2):219-232 (1987).

Kolombia, Y.A., G. Karssen, N. Viaene, P. L. Kumar, L . Joos, D. L. Coyne and W. Bert. 2017. Morphological and molecular characterisation of Scutellonema species from yam (Dioscorea spp.) and a key to the species of the genus. Nematology 19: 751-787

Van den Berg, E., Tiedt, L.R., Stanley, J.D., Inserra, R.N., Subbotin, S.A. 2017. Characterisation of some Scutellonema species (Tylenchida: Hoplolaimidae) occurring in Botswana, South Africa, Costa Rica and the USA, with description of S. clavicaudatum sp. n. and a molecular phylogeny of the genus. Nematology 19:131-173.

 

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Copyright © 1999 by Howard Ferris.
Revised: March 16, 2021.