Rev 01/15/2026
Scutellonema afribrachyurus (Andrassy, 1958), Maosa, Sirengo, Singh, Couvreur, De Waele & Bert, 2025
Synonyms:
Scutellonema brachyurus Type B Scutellonema brachyurum Type B
Nomenclature Note: According to the International Code of Zoological Nomenclature (ICZN, Art. 31.2), the genus name and species name must be in gender agreement. Since the name ending of Scutellonema is gender neuter (ICNZ, Art. 30.1.2), the correct name for the species should be brachyurum as used by Andrassy (1958). However, Maosa et al (2025) present a convincing argument in support of the name ending brachyurus and herein that form is accepted in the interest of consistency.
Scutellonema brachyurus Clades
Through an integrative taxonomy approach, Van den Berg et al. (2013, 2017) distinguished Type A and B of S. brachyurus, based on D2-D3 of 28S rRNA, ITS rRNA and COI mtDNA gene sequences. Type A is predominantly found in the USA, Europe and Asia, while Type B is mainly observed in Africa. Some putative morphological differences between Type A and B include the number of lip annuli (4-6 vs mainly three annuli), variation in the number of regular and irregular blocks on the basal lip annulus (4-12 vs 8-20 blocks) and the position of the secretrory-excretory pore in relation to the pharyngeal lobe (mostly opposite the anterior part to about the middle of the lobe vs rarely opposite the middle to mostly the posterior part of the lobe). Additional differences in c′ ratio, tail length and male stylet length, c and o ratios, further differentiate the two types. Accordingly, Maosa et al (2025) redescribed S. brachyurus Type B as Scutellonema afribrachyurus.
Scutellonema afribrachyurus is characterizad by characterised by a combination of the following: lip region with usually three to exceptionally five annuli, basal lip annulus with ca 8-20 blocks, stylet 21-32 um long, a = 20-34, c′ = 0.5-1.4, S-E pore located rarely opposite the middle to mostly posterior part of the pharyngeal lobe, lateral field areolated at level of the scutella, spermatheca small, rounded and empty, tail bluntly rounded, dorsally convex with 9-17 annuli. Males rare.
Females:
Lateral fields with four incisures, areolated anteriorly and at level of scutella.
Lip region continuous to slightly set off, usually with three annuli, exceptionally up to five. Basal lip annulus with ca 8-20 irregular blocks resulting from longitudinal striations.
Stylet length 21-32 um, well developed with basal knobs rounded posteriorly and indented anteriorly
Pharynx with dorso-pharyngeal gland opening located 3-6 um posterior to stylet base, median bulb round to poval, about half body diam. with strong valve; pharyngeal glands with dorsal overlap of intesatine
Secretory-excretory pore located usually posterior part of pharyngeal gland lobe
Didelphic-amphidelphic with two outstretched genital tracts. Spermatheca small, rounded and without sperms. Vagina with thickened walls, frequently accompanied by indistinct small vaginal glands. Epiptygmata present, appearing double and folded into vulval opening.
Scutella moderately sized with rounded shape, situated three annuli either anterior or posterior to anus. Tail bluntly roundedwith 9-17 annuli.
Males:
Males rare. Similar to females with a slightly less robust stylet
Bursa prominent anrounded, extending to tail tip.
Gubernaculum protruding with distinct titillate.
Scutella located opposite or just posterior to cloaca. Tail 13-19 um long
Ref Maosa et al., 2025
[
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Primarily Africa. Species description baserd on specimens collected in Kenya, Uganda, Tanzania and South Africa (Maosa et al., 2025)
Ectoparasite of roots, but may invade the deeper cortical layers and become endoparasitic.
Finger millet, potato, leafy greens, maize and banana.
Ecophysiological Parameters:
Grass rotations between tobacco crops in Zimbabwe can be effective (Shepherd, 1968).
Fumigation with DBCP eliminated Scutellonema populations in cotton grown in Tanzania.
Heat treatment and use of nematicides on amaryllis bulbs grown in the greenhouse have been employed (Johansson & Niedieck, 1964).
Resistance
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Andrássy, I. 1958. Hoplolaimus tylenchiformis Daday, 1905 (syn. H. coronatus Cobb, 1923) und die Gattungen der Unterfamilie Hoplolaiminae Filipjev, 1936. Nematologica 3:44-56.
Maosa, J., Sirengo, D.K., Singh, P.R., Couvreur, M., De Waele, D. and Bert, W. 2025. Description of African Scutellonema brachyurus Type B populations as Scutellonema afribrachyurus n. sp. (Tylenchida: Hoplolaimidae) based on integrative taxonomy. Nematology 27: 1055-1080.
Sher, S.A. 1963. Revision of the Hoplolaiminae (Nematoda) III. Scutellonema Andrassy, 1958. Nematologica 9:421-443.
Van den Berg, E., Tiedt, L.R., Coyne, D.L., Ploeg, A.T., Navas-Cort�s, J.A., Roberts, P.A., Yeates, G.W. and Subbotin, S.A. 2013. Morphological and molecular characterisation and diagnostics of some species of Scutellonema Andr�ssy, 1958 (Tylenchida: Hoplolaimidae) with a molecular phylogeny of the genus. Nematology 15: 719-745. DOI: 10.1163/ 15685411-00002714
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. DOI: 10.1163/15685411-0000303