Scutellonema (Steiner, 1937) Andrassy, 1958
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.,
Labial region narrow truncate to offset rounded; annulated, with or
without longitudinal striae. First labial
six sectors, lateral sectors smaller than the others (SEM).
apertures oval between labial disc and lateral sectors.
field with four lines usually
areolated near phasmids
and anteriorly, sometimes transverse striae scattered over whole
Labial framework, stylet, and stylet knobs average-sized for the
family; knobs rounded to indented.
esophageal gland opening 4 to 8 Âµm from stylet
Esophageal gland overlap dorsal and lateral.
Two genital branches outstretched, equally developed.
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
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)
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
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).
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