Truxonchus, Siddiqi, 1984

Vu, Tam T. T., 2021, A newspecies of araregenus, Truxonchus quangi sp. n. (Mononchida, Anatonchidae) from Bat Xat nature reserve in Lao Cai Province, Vietnam, Zootaxa 4985 (2), pp. 253-260 : 258-259

Currently, nine species of the genus Truxonchus have been recorded. The following key is based on characteristics of females and adapted from Ahmad and Jairajpuri (2010):

1 Tail cylindroid with bluntly rounded tip, c´ less than 3 ( ♀: L = 3.2 mm; a = 39; b = 3.4; c = 27; c´ = 2–2.5; V = 68; ♂: unknown; Germany)..................................................................................... mulveyi

- Tail long filiform or elongate conoid with sharp or rounded tip, c´ > 3........................................... 2

2 Tail long filiform, caudal glands present and spinneret subventral, c´ = 18.5–20.5, advulval pores present ( ♀: L = 4.8–5.8 mm; a = 35.7–37.3; b = 4.8–4.9; c = 3.4–3.5; c´ = 18.8–20.5; V = 45–47.2; ♂: unknown; Vietnam).............. quangi sp. n.

- Tail elongate conoid with sharp or rounded tip, c´ ≤ 14........................................................ 3

3 c´ = 12–14, buccal cavity oblong, 1.7–1.9 as long as wide ( ♀: L = 5.8–6.5 mm; a = 36–43; b = 4.6–5; c = 4.3–5.4; c´ = 12–14; V = 49–55; ♂: L = 5.9–6.3 mm; a = 40–50; b = 4.5–5; c = 5.5–5.9; supplements = 20; The Netherlands, Denmark, Germany, UK, Poland, Norway, Faroe Islands, Switzerland, Austria, Slovakia, Spain, USA, Canada)................... dolichurus

- c’ <12, buccal cavity nearly globular, barely longer than wide................................................. 4

4 Large nematodes 4–6 mm, c’ = 10–12.................................................................... 5

- Smaller nematodes 2–3.5 mm, c’ ≤ 8..................................................................... 6

5 Body slender, a = 50–71, caudal spinneret subventral, L = 4.8–6 mm, teeth large ( ♀: L = 4.8–6.0 mm; a = 50–71; b = 4.3–6.5; c = 8–12; c´ = 11–12; V = 60–67; ♂: L = 4.8–6.0 mm; a = 56–78; b = 4.8–5.9; c = 6.6–10.8; supplements = 17–19; USA).......................................................................................... gracilicaudatus

- Body less slender, a = 44–50, caudal spinneret terminal, L = 4–4.8 mm, teeth smaller ( ♀: L = 4.8–6.0 mm; a = 44–48.4; b = 4.8–5.2; c = 7.5–10; c´ = 10; V = 63–67; ♂: L = 3.8–4.6 mm; a = 42–51; b = 4.7–5.2; c = 8.3–10.3; supplements = 15–16; USA)....................................................................................... paralleni

6 c’ = 7–8 ............................................................................................ 7

- c’ = 3–4 ............................................................................................ 8

7 Tail subacute terminal, caudal glands and spinneret absent ( ♀: L = 2.5–3.5 mm; a = 36–46; b = 4.2–5.6; c = 8–13; c´ = 7–8; V = 60–66; ♂: L = 2.1–3.2 mm; a = 33–50; b = 4.2–5.6; c = 8–13; supplements = 12–18; USA)................. subacutus

- Tail rounded terminal, caudal glands present and spinneret terminal ( ♀: L = 2.5–3.5 mm; a = 33–50; b = 4.4–5.5; c = 6.7–11; c´ = 8; V = 60–66; ♂: L = 2.7–3.0 mm; a = 37–548; b = 4.7–5.5; c = 8.5–10; supplements = 12–17; USA)............ alleni

8 Addvuval pappilae present, vagina with sclerotized pieces ( ♀: L = 2.4–3.2 mm; a = 26–39; b = 4.0–4.8; c = 13–17; c´ = 3.0–4; V = 65–71; ♂: unknown; Bulgaria).................................................................. genovi

- Addvuval pappilae absent, vagina without sclerotized pieces ( ♀: L = 3.6 mm; a = 30; b = 4.8; c = 13.6; c´ = 4.2; V = 65; ♂: unknown; Bulgaria)............................................................................. penevae