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Laimaphelenchus africanus n. sp. (Tylenchomorpha: Aphelenchoididae) from South Africa, a morphological and molecular phylogenetic study, with an update to the diagnostics of the genus

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May 21, 2021

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Figure 1:

Line drawings of Laimaphelenchus africanus n. sp. (B, D, G, L, M: Male; A, C, E, F, H-K: Female). (A and B): Pharynx; (C and D): Anterior end; (E and F): Part of reproductive system; (G and H): Total body; (I and J): Details of the stalk at the tail tip; (K and M): Posterior body region; (L): Spicule.
Line drawings of Laimaphelenchus africanus n. sp. (B, D, G, L, M: Male; A, C, E, F, H-K: Female). (A and B): Pharynx; (C and D): Anterior end; (E and F): Part of reproductive system; (G and H): Total body; (I and J): Details of the stalk at the tail tip; (K and M): Posterior body region; (L): Spicule.

Figure 2:

Light photomicrographs of Laimaphelenchus africanus n. sp. (A-C, E, G-K, female; D, F, F1, F2, male). (A): Part of pharynx; (B-D): Anterior end; (E): Part of reproductive system; (G and H): Vulva; (F, I-K): Posterior body region; (F1): Spicule; (F2, I1-K1): Details of the stalk at the tail tip. (Scale bars: B-D, F1, F2, G, H, I1-K1 = 5 µm; A, E, F, I-K = 10 µm).
Light photomicrographs of Laimaphelenchus africanus n. sp. (A-C, E, G-K, female; D, F, F1, F2, male). (A): Part of pharynx; (B-D): Anterior end; (E): Part of reproductive system; (G and H): Vulva; (F, I-K): Posterior body region; (F1): Spicule; (F2, I1-K1): Details of the stalk at the tail tip. (Scale bars: B-D, F1, F2, G, H, I1-K1 = 5 µm; A, E, F, I-K = 10 µm).

Figure 3:

Scanning electronic microscopy of Laimaphelenchus africanus n. sp., female. (A-C): Details of anterior end; (D): Secretory-excretory pore; (E): Lateral field; (F): Vulva in ventral view; (G and H): Tail in ventro-lateral and ventral views; (I-L): Details of the stalk at the tail tip. (Scale bars = 3 µm)
Scanning electronic microscopy of Laimaphelenchus africanus n. sp., female. (A-C): Details of anterior end; (D): Secretory-excretory pore; (E): Lateral field; (F): Vulva in ventral view; (G and H): Tail in ventro-lateral and ventral views; (I-L): Details of the stalk at the tail tip. (Scale bars = 3 µm)

Figure 4:

Bayesian 50% majority rule consensus tree of Laimaphelenchus africanus n. sp. based on LSU rDNA D2-D3 sequences under GTR + I + G model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The new sequences are indicated in bold.
Bayesian 50% majority rule consensus tree of Laimaphelenchus africanus n. sp. based on LSU rDNA D2-D3 sequences under GTR + I + G model. Bayesian posterior probability values more than 0.50 are given for appropriate clades. The new sequences are indicated in bold.

Figure 5:

The close-up view (pruned tree) showing the clade L in the original Bayesian 50% majority rule consensus tree of Laimaphelenchus africanus n. sp. based on LSU rDNA D2-D3 sequences under GTR + I + G model. Data on stalk type, vulval flap status and lateral lines number for the currently sequenced species are given in right.
The close-up view (pruned tree) showing the clade L in the original Bayesian 50% majority rule consensus tree of Laimaphelenchus africanus n. sp. based on LSU rDNA D2-D3 sequences under GTR + I + G model. Data on stalk type, vulval flap status and lateral lines number for the currently sequenced species are given in right.

Morphometric characteristics of Laimaphelenchus africanus n_ sp_

Characteristics Holotype female Paratype females Paratype male
n 21 1
L (micron) 916 898 ± 67 (750–987) 696
a 48.2 42.6 ± 3.0 (37.0–48.2) 43.5
b 11.2 11.6 ± 0.6 (10.8–12.7) 10.4
b′ 4.4 4.7 ± 0.4 (4.1–5.7) 4.9
c 22.3 24.3 ± 2.3 (20.8–30.8) 17.8
c′ 3.4 3.2 ± 0.4 (2.5–3.8) 2.4
V or T % 71.2 70.0 ± 1.1 (67.1–71.9) 58.2
Cephalic region width 7 6.8 ± 0.4 (6–7) 6.5
Cephalic region height 2.5 2.8 ± 0.5 (2–4) 3
Stylet length 12.5 11.8 ± 0.6 (10.0–12.5) 12
Conus length 6 4.9 ± 0.5 (4–6) 5
m 48 41.7 ± 3.2 (34.8–50.0) 41.7
Anterior end to valves of median bulb 63 62.0 ± 4.1 (53–67) 56
MB 76.8 80.0 ± 2.5 (76.5–84.4) 83.6
Anterior end to nerve ring 100 97.0 ± 6.8 (80–106) 82
Anterior end to pharyngeal intestinal junction 82 77.0 ± 5.5 (65–85) 67
Anterior end to posterior of pharyngeal glands 206 192 ± 17.6 (150–217) 143
Overlap 124 115.7 ± 14.2 (83–141) 76
Median bulb width 15 12.0 ± 1.3 (10–15) 10.5
Median bulb length 17 16.0 ± 1.3 (13–18) 15
Diam. at median bulb 15 16.0 ± 0.9 (14–17)
Max. diam. 19 21.0 ± 2.1 (16–25) 16
Median bulb length/diam. ratio 1.1 1.4 ± 0.1 (1.1–1.6) 1.4
Anterior to SE-pore 102 100 ± 7.4 (87–112) 86
Anterior end-vulva 652 628 ± 50.4 (520–700)
Post-vulval uterine sac (PUS) 100 91.0 ± 14.2 (63–125)
Vulva to anus distance 308 238 ± 73.4 (139–388)
PUS/vulva to anus (%) 32.5 41.3 ± 11.6 (23.2–63.1)
PUS/L (%) 10.9 10.2 ± 1.3 (7.6–12.7)
Diam. at anus or cloaca 12 12.0 ± 1.1 (9–13) 16
Tail 41 37.0 ± 3.6 (30–44) 39
Spicules (arc) 17
Spicules (chord) 16.6
Calamus 7
Spicules width 5
Language:
English
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1 times per year
Journal Subjects:
Life Sciences, Life Sciences, other