Table 1.
Morphometric data of Geocenamus vietnamensis n. sp. from fixed specimens. All measurements are in μ m (except for ratio) and in the form: mean ± s.d. (range).
| Paratypes | ||||
|---|---|---|---|---|
| Geocenamus measurement | Holotype female | Allotype male | Female (n = 18) | Male (n = 15) |
| Body length (L) | 877 | 712 | 875 ± 64 (776–979) | 706 ± 35 (631–754) |
| Lip region height | 3.1 | 3.6 | 3.6 ± 0.5 (3.1–4.2) | 3.4 ± 0.3 (3.1–3.6) |
| Lip region width | 6.2 | 5.7 | 6.5 ± 0.7 (5.2–7.3) | 6.1 ± 0.5 (5.2–6.8) |
| Stylet cone | 18.7 | 15.6 | 15.7 ± 1.4 (13.5–18.7) | 15.1 ± 1.4 (13–17.7) |
| Stylet shaft | 9.4 | 8.3 | 10.4 ± 0.5 (9.4–11.4) | 8.8 ± 1.6 (5.7–10.9) |
| Stylet length | 28 | 24 | 26 ± 1 (24–28) | 24 ± 1 (23–26) |
| Stylet knob height | 2.1 | 1.6 | 2.0 ± 0.4 (1.6–2.6) | 1.9 ± 0.4 (1.6–2.6) |
| Stylet knob width | 4.2 | 3.1 | 3.5 ± 0.8 (1.6–4.2) | 3.6 ± 0.2 (3.12–3.6) |
| Stylet base to dorsal gland orifice (DGO) | 3.1 | 3.12 | 2.9 ± 0.3 (2.6–3.1) | 3.0 ± 0.3 (2.6–3.6) |
| Body width at stylet base | 16.6 | 11.9 | 16.7 ± 2.8 (13.0–20.8) | 13.7 ± 1.0 (11.9–15.6) |
| Maximum body diameter (MBD) | 31 | 22 | 29 ± 3 (25–34) | 22 ± 1 (22–25) |
| Body width at vulva | 22 | 27 ± 3 (22–34) | ||
| Body width at anus | 18.7 | 13 | 19.1 ± 2.4 (15.6–23.9) | 16.1 ± 2.6 (13–21.8) |
| Anterior end to the end of pharynx | 152 | 125 | 138 ± 9 (124–152) | 122 ± 7 (114–135) |
| Anterior end to the end of median bulb | 89 | 73 | 81 ± 8 (74–99) | 72 ± 5 (67–81) |
| Anterior end to median valve | 78 | 65 | 72 ± 7 (66–88) | 63 ± 5 (57–71) |
| Median bulb width | 10.9 | 9.8 | 11.0 ± 0.7 (10.4–12.5) | 9.6 ± 1.2 (6.8–10.4) |
| Median bulb length | 15.6 | 15.6 | 17.0 ± 1.6 (14.6–18.7) | 15.5 ± 1.2 (13.5–17.7) |
| Anterior end to nerve ring | 86 | 86 | 90 ± 6 (83–104) | 83 ± 8 (74–99) |
| Anterior end to secretory–excretory pore | 94 | 89 | 94 ± 5 (86–102) | 86 ± 6 (76–97) |
| Isthmus length | 39 | 31 | 32 ± 4 (26–39) | 30 ± 2 (26–31) |
| Basal bulb length | 27 | 21 | 25 ± 2 (23–28) | 22 ± 2 (19–25) |
| Tail length | 86 | 75 | 104 ± 14 (85–125) | 84 ± 9 (68–96) |
| Spicule length | 21 | 20 ± 1 (19–22) | ||
| Gubernaculum length | 5.2 | 6.5 ± 1.0 (5.2–7.8) | ||
| Anus to phasmid | 23 | 17.7 | 23 ± 3 (18.7–26) | 18.6 ± 2.6 (13.5–23) |
| Tail annuli (ventral) | 61 | 48 | 64 ± 5 (58–73) | 59 ± 6 (48–65) |
| a = L/MBD | 28 | 33 | 30 ± 3 (25–34) | 32 ± 1 (29–33) |
| b′ = L/distance from anterior end to pharyngo–intestinal valve | 5.8 | 5.7 | 6.4 ± 0.5 (5.8–7.2) | 5.8 ± 0.2 (5.5–6.2) |
| c = L/Tail length | 10.2 | 9.5 | 8.5 ± 0.8 (7.3–10.2) | 8.5 ± 0.7 (9.3–9.5) |
| c′ = Tail length/ABD | 4.6 | 5.8 | 5.5 ± 0.7 (4.3–6.5) | 5.3 ± 0.7 (4.3–6.3) |
| V = Anterior end to vulva/L ×100 | 50 | 49 ± 2 (47–52) | ||
| M = stylet conus length/stylet length ×100 | 67 | 65 | 60 ± 3 (56–67) | 62 ± 4 (57–69) |
| MB = % distance from anterior end to median bulb in relation to the length of pharynx | 51 | 52 | 52 ± 3 (49–59) | 51 ± 1 (50–53) |
| O = % distance of dorsal pharyngeal gland opening from stylet knobs in relation to the stylet length | 11.1 | 13.0 | 11.0 ± 1.3 (9.6–13.0) | 12.5 ± 1.3 (10.2–14.3) |
| Phasmid % tail | 27 | 24 | 22 ± 2 (18.3–27) | 22 ± 3 (17–28) |
Figure 1:
Geocenamus vietnamensis n. sp. (♀). (A): Entire body; (C): Pharyngeal region; €: Head region; (F): Lateral field at mid-body; (G): Vulva region with posterior gonad; (H): tail region; (K): Vulva region. (♂). (B): Entire body; (D): Pharyngeal region; (I): Tail region; (L): Cloacal region showing spicule and gubernaculum.
Figure 2:
Geocenamus vietnamensis n. sp. (Light microscope). (A): Entire body of female and male (female in the left side and male in the right side); (B): Head region of the female; (C): Head region of the male; (D): Vulva region with spermatheca at arrow position; (E): Female pharyngeal region; (F): Spicule and Gubernaculum; (G): Phasmid in the tail of the male; (H): Vulva region; (I): Tail of the male; (J): Phasmid in the tail of the female; (K): Lateral field; (L): Tail of the female.
Figure 3:
Geocenamus vietnamensis n. sp. (SEM ♀). (A): Labial region; (B): Head region; (C): Enface view with amphid orifice (ap) at arrow position; (D): Vulva region with lateral field at arrow position; €: Secretory–excretory pore (ep); (F): Vulva with epyptigma (ept) at arrow position; (G): anus position (a) and phasmid position (ph); (H): phasmid position; (I): Tail region; (J): Tail tip.
Figure 4:
Geocenamus vietnamensis n. sp. (SEM ♂). (A): Labial region; (B): Head region; (C): Enface view with amphid orifice (ap) at arrow position; (D): Lateral field; (E): Secretory–excretory pore; (F): Tail region with spicule (sp); (G): Tail tip; (H): Side view of tail with spicule (sp) and phasmid (ph) positions; (I): Cloacal region; (I): Cloaca with hypotigma; (J): Phasmid position.
Figure 5:
Phylogenetic tree generated from D2–D3 of 28S rDNA sequences based on ML method (TN93 + G model) with 1,000 replications.
Figure 6:
Phylogenetic tree generated from ITS rDNA sequences based on ML method (GTR + G model) with 1,000 replications.