Figure 1
Scanning electron micrograph (SEM) images of Tylenchus zeae n. sp.
A: Female specimen, anterior end, arrow pointing toward the excretory pore; B: Female specimen, head; C: Female specimen, face view; D: Lateral field (midbody); E: Female specimen, anal opening; F: Female specimen, vulval opening; G: Male specimen, spicule; H: Female specimen, arrow showing the anal opening; I: Female specimen, tail; J: Male specimen, posterior end.
Table 1
Morphometrics of Tylenchus zeae n. sp. All measurements are in μm and in the form: mean ± standard deviation (range).
| Character | Holotype | Female (n = 9) | (Male n = 4) |
|---|---|---|---|
| L | 830 | 830.0 ± 39.3 (765.0–895.0) | 813.0 ± 45 (775.0–885.0) |
| Stylet | 20 | 20.0 ± 0.7 (20.0–22.0) | 20.0 (20.0–20.0) |
| MBW | 27 | 25.0±2.58 (20.0–30.0) | 22.0 (20.0–25.0) |
| Ant. end to exc. pore distance | 102 | 103.0 ± 6.0 (92.0–115.0) | — |
| Ant. end to esophago-intestinal valve | 122 | 123.0 ± 5.5 (115.0–130.0) | 123.0 ± 2.0 (120.0–125.0) |
| Tail | 112 | 121.0 ± 5.9 (112.0–127.0) | 127.0 ± 5.0 (122.0–135.0) |
| a | 31 | 33.0 ± 3.7 (28.0–42.0) | 37.0 ± 2.0 (35.0–39.0) |
| b | 7 | 7.0 ± 0.5 (6.0–8.0) | 7.0 ± 0.4 (6.0–7.0) |
| c | 7 | 7.0 | 6.0 ± 0.3 (6.0–7.0) |
| V% | 63 | 63.0 ± 1.2 (61–65%) | — |
| Anal body width | 15 | 15 ± 1.28 (12.0–17.0) | 13.0 (12.0–14.0) |
| Spicules | — | — | 21.0 ± 1.0 (20.0–23.0) |
| Gubernaculum | — | — | 6.0 ± 0.5 (5.0–6.0) |
[i] L, body length; MBW, maximum body width.
Figure 2
Photomicrographs of Tylenchus zeae n. sp. males and females. A–B: Anterior end with arrows pointing toward the excretory pore; C: Excretory pore; D: Areolated lateral field; E: Entire female body; F: Female basal bulb; G: Female gonad; H–I: female posterior end with arrow pointing the anal area (H); J: Female vulva region with arrow pointing toward the spermatheca; K: Male spicule.
Figure 3
Line drawings of Tylenchus zeae n. sp. A: Female pharyngeal region; B: Female lip region showing stylet; C: Areolated lateral field; D: Male spicule, gubernaculum, and bursa. E: Vulval region showing vulva, uterus, and spermatheca; F–G: female tails.
Table 2
Measurements for Tylenchus zeae n. sp. comparison with T. rex and T. sherianus female populations. Measurements are in μm and in the form: mean ± standard deviation (range).
| Character | T. zeae n. sp. (n = 9) | T. sherianus Andrassy (1979) | T. rex Brzeski (1996) (n = 12) | T. rex Andrassy (1979) | T. rex Geraert (2008) |
|---|---|---|---|---|---|
| L | 830.0 ± 39.3 (765.0–895.0) | 750–840 | 1007.0 ± 52.4 (963.0–1087.0) | 960.0–980.0 | 960–1009 |
| Stylet | 20.3 ± 0.7 (20.0–22.0) | 19–20 | 20.4 ± 0.4 (19.5–205) | 20.0–21.0 | 19–21 |
| MBW | 26.0 (20.0–30.0) | — | 30.7 (based on author calculations) | — | — |
| Ant. to exc. pore distance | 103.0 ± 6.0 (92.0–115.0) | — | 130.0 ± 4.9 (121.0–157.0) | — | — |
| Ant. to esophago-intestinal valve | 123.0 ± 5.5 (115.0–130.0) | — | 151.0 ± 4.4 (142.0–157.0) | — | 133–157 |
| Tail | 120.0 ± 5.9 (112.0–127.0) | 100–116 | 134.0 ± 4.7 (127.0–141.0) | 134.0–160.0 | 127–160 |
| a | 33.0 ± 3.7 (28.0–42.0) | 25–28 | 32.8 ± 1.9 (30.0–36.0) | 32.0–34.0 | — |
| b | 7.0 ± 0.5 (6.0–8.0) | 5.7–6.0 | 6.7 ± 0.3 (6.4–7.3) | 6.8–7.0 | — |
| c | 7.0 | 6.8–8.0 | 7.5 ± 0.4 (7.0–8.4) | 6.0–7.1 | 6.0–8.4 |
| V% | 63.0 ± 1.2 (61–65%) | 65–68 | 64.9 ± 0.8 (63.0–66.0) | 61.0–63.0 | 61–66 |
| MB% | — | 43 | 44.2 ± 0.8 (43–45) | 43–45 | 43–45 |
[i] L, body length; MBW, maximum body width.
Figure 4
Phylogenetic relationships of Tylenchus zeae n. sp. with other select Tylenchidae, as inferred from a 1585 bp alignment of 18S rRNA sequences, according to the GTR + I + G model of nucleotide substitution and incorporated into MrBayes (MB) as described. A 50% majority rule consensus tree was generated with posterior probabilities (PP) shown on appropriate branches, with Aphelenchoides besseyi as the outgroup. New sequences are indicated in bold.
Figure 5
Phylogenetic relationships of Tylenchus zeae n. sp. with other select Tylenchidae, as inferred from an 822 bp alignment of 28S rRNA sequences, according to the GTR + I + G model of nucleotide substitution and incorporated into MrBayes (MB) as described. A 50% majority rule consensus tree was generated with posterior probabilities (PP) shown on appropriate branches, with Bursaphelenchus mucronatus as the outgroup. New sequences are indicated in bold.
Figure 6
Phylogenetic relationships of Tylenchus zeae n. sp. with other select Tylenchidae, as inferred from a 418 bp alignment of mitochondrial COI sequences, according to the GTR + I + G model of nucleotide substitution and incorporated into MrBayes (MB) as described. A 50% majority rule consensus tree was generated with posterior probabilities (PP) shown on appropriate branches, with Bursaphelenchus conicaudatus as the outgroup. New sequences are indicated in bold.