Species belonging to the genus
The genus has a cosmopolitan distribution, with Europe being particularly rich in species (Andrássy, 2006). To date, 30 species have been described from this genus worldwide (Kim et al., 2018). Most of the species in the genus have been collected from moss, leaf litter, and forest soil (Susulovsky and Winiszewska, 2002; Winiszewska and Susulovsky, 2003; Orselli and Vinciguerra, 2007) associated with riverbanks and mountainous regions (Susulovsky and Winiszweska, 2006; Farahmand et al., 2009).These predatory nematodes play an important role in bioregulation of litter and soil communities (Dipchikova et al., 2019).
During a survey of the Jonkershoek Mountains in Stellenbosch, South Africa, samples were collected from seven localities to study nematodes associated with leaf litter. Among the various nematodes extracted, one population of
Measurements and drawings of mounted
Mounted specimens were removed carefully from slides, hydrated in distilled water, dehydrated in a graded ethanol series, critical point dried, and coated with gold (Green, 1967), and observed under a JEOL JSM-7800F Field Emission Scanning Electron Microscope at 5 kV.
Genomic DNA was extracted from a single female specimen using the modified Chelex method as described by Rashidifard et al. (2019). The DNA was amplified using the following reagents: 12.5 µl master mix (Promega), 4 µl of specimen’s DNA, 1 µl of forward and reverse primers (10 µM), and 6.5 µl of ddH2O in a Vacutec thermocycler machine (
The newly generated sequences were aligned using MUSCLE alignment tool (Edgar, 2004) in Geneious Prime 2020.2.3 (
Bayesian inference (BI) analyses were conducted using MrBayes v3.1.2 (Ronquist and Huelsenbeck, 2003) implemented in Geneious Prime 2020.2.3. Two Markov chain Monte Carlo (MCMC) were run from a random starting tree for 2 million generations and trees were sampled every 100 generations. Burn-in sampled trees (25%) were discarded. The remaining trees were used to calculate the 50% majority rule consensus tree using the MCMC algorithm to estimate the Bayesian posterior probabilities (BPP) (Larget and Simon, 1999).
Female: Slender to moderately slender (a = 23–30) nematodes, 1.78–2.14 mm long. Body cylindrical, tapering toward tail terminus. Habitus ventrally curved at posterior end upon fixation, J-shaped. Cuticle moderately thick, with two layers, outer layer thinner than inner layer, with fine transverse striations. Cuticle appears more thickened at vulva and caudal region (2–4 µm). Lateral chord 27–38% of midbody diameter. Body pores obscure. Lip region rounded, offset by weak depression but of similar width with adjacent body, about 3–4 times as wide as high. Lips amalgamated, rounded to angular. Labial papillae slightly more conical and protruding than cephalic papillae.
Amphidial fovea cup-shaped, opening (oval to ellipsoid) at level of anterior denticle above dorsal tooth apex, 3–6 µm in diameter and occupying 1/5–1/6 of lip region width. Stoma consists of a vestibulum and a buccal cavity 1.4–1.7 times as long as wide, with 2–4 µm thick walls and tapering at its base, funnel shaped. Dorsal tooth of medium size situated in lower anterior half of buccal cavity, its apex sharply pointed, located 30–34 µm or 75–81% of the buccal cavity length from its base, its upper edge slightly curved, directed forward. Subventral denticles present, 11–14 in number, relatively large, orientated anteriorly, separated, arranged irregularly in some specimens. Two small foramina observed. Pharynx muscular, cylindrical, about 8–10 times as long as wide, surrounding basal part of stoma. Pharyngeal gland nuclei and outlets indistinct. Nerve ring located at 29–33% of the neck length. Secretory-excretory pore visible, situated 30–38% of the neck length. Cardia oval to rounded, smooth, 0.3–0.5 times as long as wide, 0.2 times as long as body diameter at neck base, non-tuberculate. Intestine uniformly granulated; inner surface lined by short rod-like structures (bacillary layer).
Genital system didelphic-amphidelphic. Genital branches almost symmetrical; anterior branch 300–390 µm and posterior branch 252–362 µm long. Ovaries reflexed, well developed, similar; anterior ovary 124–218 µm and posterior ovary 124–186 µm long; not reaching oviduct-uterus junction. Oviduct with well-marked
Tail conical, 144–158 µm long, bent ventrally, distal 1/3 more curved ventrad, sickle shaped, tapering to finely pointed terminus. Hyaline portion 7 µm long, 5% of tail length. Caudal glands absent. Three pairs of caudal pores present.
Males: Not found.
The type material was collected from leaf litter and moss near the First Waterfall hiking trail in the Jonkershoek mountains, Stellenbosch, South Africa (coordinates 33°59ʹ54.9ʺ S, 18˚58ʹ59.7ʺ E).
Holotype female (slide 51180), and one female and three juvenile paratypes (slide 51181) deposited in the National Collection of Nematodes (NCN), Agricultural Research Council-Plant Health and Protection (ARC-PHP), Pretoria, South Africa; 23 female paratypes deposited in the nematode collection of the University of the Free State (UFS), Bloemfontein, South Africa.
The specific epithet refers to the geographical origin of the new species in the Jonkershoek Mountains in South Africa.
The combination of the above-mentioned characters differentiates
During the survey, two sequences for each gene were generated. However, since they were identical only one sequence of 18 S rDNA (accession number MW218002, 848 bp long) and one sequence of 28 S rDNA (accession number MW227656, 730 bp long) were selected for phylogenetic analyses. A BLASTn search for matches to the partial 18 S rDNA sequence of
The 18 S alignment was prepared using 47 sequences (739 nt long) in which 223 nt were variable, while the 28 S alignment contained 23 sequences (760 nt long), of which 494 nt were variable.
Bayesian inference analyses using partial 18 S rDNA sequences clustered
During this study, a population of
Morphometric data of
Female | ||
---|---|---|
Characters | Holotype | Paratypes |
n | – | 24 |
L | 1.84 | 1.97 ± 0.1 (1.78–2.14) |
a | 23 | 26.9 ± 1.8 (23.0–29.7) |
b | 3.1 | 3.3 ± 0.2 (3.0–3.5) |
c | 11.6 | 13.0 ± 0.7 (11.6–14.3) |
c’ | 3.3 | 3.2 ± 0.2 (2.9–3.5) |
V | 67 | 63.3 ± 2.6 (58.6–67.4) |
Lip region height | 9 | 9.8 ± 1.3 (8.0–12.0) |
Lip region width | 37 | 37.0 ± 2.4 (32.0–40.0) |
Amphid from anterior end | 14.4 | 14.6 ± 1.7 (11.2–18.0) |
Buccal cavity length | 42 | 41.6 ± 1.4 (38.0–44.0) |
Buccal cavity width | 26 | 27.2 ± 1.9 (24.0–31.2) |
Position of tooth apex (%) | 29 | 28.5 ± 2.4 (25.0–33.0) |
Nerve ring to anterior end | 195 | 184 ± 5.0 (175–195) |
Secretory-excretory pore to anterior end | 220 | 206 ± 14.0 (185–220)* |
Neck length | 600 | 597 ± 10.9 (580–610) |
Cardia length | 11.2 | 12.3 ± 1.3 (10.0–15.0) |
Cardia width | 36 | 35.0 ± 2.6 (30.0–40.0) |
Cuticle – lip region | 2.0 | 1.8 ± 0.3 (0.8–2.4) |
Cuticle – at vulva | 2.4 | 2.8 ± 0.9 (2.0–4.0) |
Cuticle – at tail | 4 | 3.0 ± 1.0 (2.0–4.0) |
Lateral chord width | 22 | 25 ± 2.4 (20.0–28.0) |
Body diameter – neck base | 67 | 67.2 ± 2.7 (64.0–75.0) |
Body diameter – at midbody | 80 | 73.5 ± 4.3 (66.0–82.0) |
Body diameter – at anus | 48 | 46.6 ± 2.4 (44.0–52.0) |
Vagina length | 26 | 31.2 ± 2.9 (26.0–35.0) |
Rectum length | 36 | 40.1 ± 3.1 (36.0–48.0) |
Tail length | 158 | 152 ± 4.7 (144–158) |
Hyaline length | 6 | 6.8 ± 1.7 (4.0–8.0) |
Egg length | 95 | 84.0 ± 7.5 (76.0–95.0)** |
Egg width | 60 | 45.0 ± 9.0 (37.0–60.0)** |
Notes: *
**