Basirotyleptus, Jairajpuri, 1964

Islam, Md Niraul & Ahmad, Wasim, 2022, Description of five new and six known species of the genus Basirotyleptus Jairajpuri, 1964 (Nematoda: Dorylaimida: Tylencholaimoidea) from the Western Ghats, India, European Journal of Taxonomy 791 (1), pp. 1-57 : 49-51

Key to species of the genus Basirotyleptus (modified after Goseco et al. 1974)

1. Female genital system amphidelphic ................................................................................................ 2

– Female genital system monodelphic ................................................................................................. 3

2. Tail bluntly conoid; c = 23–29, c’ = 1.4–1.7 .............................................. B. westralis Siddiqi, 1970

– Tail hemispheroid; c = 43–57, c’ = 1.0 ....................................................... B. rugosus Siddiqi, 1982

3. Female genital system mono-prodelphic .......................................................................................... 4

– Female genital system mono-opisthodelphic .................................................................................... 6

4. Body length more than 0.6 mm; spicules longer, 24–28 µm ............... B. lieberi Goseco et al., 1970

– Body length less than 0.6 mm; spicules shorter, 15–21 µm ............................................................. 5

5. Odontophore with basal flanges; post-uterine sac long, 1.8–3.5 times midbody diameter long; tail comparatively long, conoid, 18–28 µm ................................................. B. heynsi Furstenberg, 1980

– Odontophore without basal flanges; post-uterine sac short, 1.2 times midbody diameter long; tail short, conoid, 15 µm ...................................................................... B. eximius Siddiqi & Khan, 1964

6. Labial disc present ............................................................................................................................ 7

– Labial disc absent ........................................................................................................................... 17

7. Odontophore with basal flanges ...................................................................... B. constrictus sp. nov.

– Odontophore without basal flanges .................................................................................................. 8

8. Anterior uterine sac absent ..................................................................... B. ethiopicus Siddiqi, 1970

– Anterior uterine sac present .............................................................................................................. 9

9. Anterior uterine sac <15 µm or less than one midbody diameter long .......................................... 10

– Anterior uterine sac> 15 µm or more than one midbody diameter long ....................................... 12

10. Body 0.41–0.57 mm long; b = 3.8–4.2 ..................................................... B. nemoralis Siddiqi, 1970

– Body more than 6.0 mm long; b = 4.3–5.8 ......................................................................................11

11. c = 74–100; prerectum 48 µm or about 3.0 times anal body diameter ............................................... .................................................................................................... B. coronatus Siddiqi & Khan, 1965

– c = <69; prerectum 73–104 µm or 4.0–5.4 times anal body diameter ............................................... ................................................................................................ B. indicus Dhanam & Jairajpuri, 1999

12. V => 50 .......................................................................................................................................... 13

– V = <50 .......................................................................................................................................... 14

13. Body longer, L = 0.68–0.77 mm; a = 39–42; c = 80–90 ............................... B. curvus Siddiqi, 1982

– Body shorter, L = 0.45 mm; a = 28; c = 35 ................................................. B. discinus Siddiqi, 1995

14. Body less than 0.6 mm .................................................................................................................... 15

– Body more than 0.6 mm ................................................................................................................. 16

15. Pharynx short, 90 µm, b = 4.7–6.0; V = 36–43; c = 42–44 ....... B. modestus Hussain & Khan, 1968

– Pharynx long, 110–124 µm, b = 3.8–4.9; V = 42–47; c = 47–67 ................... B. safiae Siddiqi, 1997

16. Odontostyle 6.0 µm, odonotophore 10.5–11 µm; spicules 24 µm ............. B. barbarae Siddiqi, 1997

– Odontostyle 7.5–8.5 µm, odonotophore 12–15 µm; spicules 29–32 µm .... B. robustus Siddiqi, 1982

17. Odontophore flanged ...................................................................................................................... 18

– Odontophore simple, with sclerotized or slightly swollen base, not flanged ................................. 25

18. V = 47–58 ....................................................................................................................................... 19

– V = up to 47 .................................................................................................................................... 23

19. Body 0.50–0.58 mm long; posterior uterine sac 2.0–2.8 times midbody diameter long .................... ............................................................................................................... B. longisaccus Siddiqi, 1995

– Body 0.30–0.51 mm long; posterior uterine sac about as long as midbody diameter long ............ 20

20. Tail short, with rounded to hemispheroid terminus; c = 30–44 ...................................................... 21

– Tail short, conoid with acute terminus; c <28 ............................................ B. conicuadatus sp. nov.

21. Odontostyle 9.0–10 µm; neck length 110–119 µm ................................ B. syncheillus Siddiqi, 1995

– Odontostyle 7.5–8.5 µm; neck length 95–106 µm ......................................................................... 22

22. Lip region flat; V = 54–56; c’ = 0.9 ...................................................................... B. siddiqii sp. nov.

– Lip region elevated; V = 47–53; c’ = 1.2–1.7 .............................................. B. siremps Siddiqi, 1995

23. Lips separated, angular; c’ = 1.0–1.2 ............................................................. B. nindei Siddiqi, 1970

– Lips amalgamated, slightly elevated; c’ = 0.6–0.9 ......................................................................... 24

24. Longer body, L = 0.38–0.48 mm; amphids duplex; odontostyle 10–14 µm ....................................... ........................................................................................................................ B. minutus Khan, 1987

– Shorter body, L = 0.29–0.36 mm; amphids simple; odontostyle 7.5–8.5 µm ..................................... ................................................................................................................. B. deminutus Siddiqi, 1995

25. Anterior uterine sac absent ............................................................................................................. 26

– Anterior uterine sac present ............................................................................................................ 29

26. Tail conoid to digitate, with acute terminus; c’ = 1.1–1.7 .............................................................. 27

– Tail rounded to hemispheroid; c’ = <1.0 ........................................................................................ 28

27. Liplets distinct; amphids cup-shaped; odontophore about one-half of odontostyle length ................ ................................................................................................................ B. caudatus Jairajpuri, 1966

– Liplets absent; amphids stirrup-shaped; odontophore about 1.2–1.5 times odontostyle length ......... ....................................................................................................................... B. neocaudatus sp. nov.

28. V = 31–41; tail rounded, with terminal caudal pore ............................... B. acus Goseco et al., 1974

– V = 47–48; tail conoid, without terminal caudal pore ......... B. soueastus Ahmad & Jairajpuri, 1979

29. Vulva posterior, V => 50 ................................................ B. penetrans (Thorne, 1964) Siddiqi, 1969

– Vulva anterior, V = <44 ................................................................................................................. 30

30. Body long, 0.68–0.98 mm; pharyngeal bulb 20–26 µm ................................................................. 31

– Body short, 0.45–0.68 mm; pharyngeal bulb 14–20 µm ................................................................ 33

31. Cuticle without punctations; amphids stirrup-shaped ............... B. upicus Ahmad & Jairajpuri, 1979

– Cuticle bearing punctations; amphids cup-shaped ......................................................................... 32

32. Amphids duplex, cup-shaped; anterior uterine sac 24.5–46 µm; males absent .................................. ............................................................................................................................. B. goaensis sp. nov.

– Amphids simple, cup-shaped, anterior uterine sac 65 µm; males present .......................................... .............................................................................. B. rotundicaudatus ( Khan, 1987) Andrássy, 2009

33. Anterior uterine sac more than one midbody diameter long .......................................................... 34

– Anterior uterine sac less than one midbody diameter long ............................................................. 35

34. Odontostyle 10–14 µm; tail 11–16 µm ....................................................... B. basiri Jairajpuri, 1964

– Odontostyle 6.0–7.0 µm; tail 8.0–10 µm ......................................... B. minimus Jana & Baqri, 1981

35. Lip region distinctly offset; odontostyle, 11–15 µm ............................ B. pini Siddiqi & Khan, 1965

– Lip region distinctly not offset; odontostyle, 4.6 µm ......... B. striatus (Thorne, 1964) Siddiqi, 1969