Basirotyleptus pini Siddiqi & Khan, 1965

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 : 7-10

Basirotyleptus pini Siddiqi & Khan, 1965

Fig. 2 , Table 2

Basirotyleptus pini Siddiqi & Khan, 1965: 641–645 .

Basirotyleptus pini – Baqri 1991: 75–77. — Li et al. 2008: 2008–2009 .

Material examined

INDIA – Kerala State • 9 ♀♀; Kollam district, Pathanampuram ; 9º05′34.8″ N, 76º51′39.6″ E; 5–15 cm depth; 3 Nov. 2017; soil samples collected from around the roots of grasses (unidentified); slides reference number AMU/ZD/NC/ Basirotyleptus pini /1–3 • 9 ♀♀; Pathanamthitta district, Thannithode ; 9°15′21.6″ N, 76°55′19.2″ E; 5–15 cm depth; 1 Nov. 2017; soil samples collected from around the roots of shrubs (unidentified); slides reference number AMU/ZD/NC/ Basirotyleptus pini /4–6 .

Description

Female

Small sized nematodes, slightly curved ventrad or open C-shaped upon fixation; tapering gradually towards both extremities but more so towards anterior end. Cuticle with two distinct layers, 1.0–1.5 µm thick at anterior region, 2.0–2.5 µm at midbody and 2.5–3.5 μm on tail. Outer cuticle thin, smooth or with very fine transverse striations; inner layer thick, its outline irregular, loose, finely striated, with radial refractive elements. Lateral chords occupying about 30–35% of midbody diameter. Lateral body pores distinct; 1–2 in neck region; 2–3 at neck to vulval region and 5–9 at post-vulval region. Dorsal and ventral body pores indistinct. Lip region cap-like, offset by deep constriction, 2.1–2.5 times as wide as high or about two-fifths to one-half of the body diameter at neck base. Lips rounded, amalgamated, angular, projected, inner part elevated. Labial and cephalic papillae distinct and slightly raised above the labial contour. Amphids stirrup-shaped, their aperture about one-half to three-fifths as wide as lip region diameter. Stoma a long, slender truncate cone, slightly sclerotized in the perioral region. Odontostyle slender, solid, needle-like, 1.3–1.5 times the lip region diameter long. Odontophore simple, sclerotized, slightly swollen at base surrounded by pharyngeal tissue, 1.0–1.1 times the odontostyle length. Guiding ring simple, refractive, at 1.2–1.3 times the lip region diameter from anterior end. Pharynx consisting of a slender anterior part, expanding gradually into a short, pear-shaped basal bulb, with a perceptible thickening at the posterior part of its inner lining, occupying about 14–17% of total neck length. Nerve ring at 50–59% of neck length from anterior end. Cardia short, rounded to conoid, about one-fifth to one-third of the corresponding body diameter long.

Genital system monodelphic-opisthodelphic. Ovary reflexed, measuring 56–98 μm; oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally, measuring 45–95 μm, consisting of a slender distal portion and a well-developed pars dilatata. Oviduct-uterus junction marked by weak sphincter. Uterus short and tubular, measuring 19–31 μm. Anterior genital branch reduced to small sac, 0.40–0.81 times midbody diameter long. Sperm cell absent. Vagina cylindrical, extending inwards, 10.5–12.5 μm or about one-half to three-fifths (50–62%) of midbody diameter; pars proximalis vaginae 6.0–7.5 × 4.0–6.5 μm, encircled by circular muscles; pars distalis vaginae 4.0–5.0 μm with slightly curved walls; pars refringens absent. Vulva apparently a transverse slit. Prerectum 2.0–3.5 and rectum 1.1–1.3 times anal body diameter long. Tail short, rounded to conoid, 0.7–1.0 times anal body diameter long, with a pair of caudal pores on each side.

Male

Not found.

Remarks

Siddiqi & Khan (1965) described this species from Kashmir, India. Baqri (1991) reported it from South Sikkim, India, whereas, Li et al. (2008) recorded it from the China. The morphometrics of present populations conform well with the type population except in having slightly lower c ratio (33–43 vs 43–55). The present populations conform well with the Sikkim population except for longer total stylet (24.5–26.0 vs 18–23) and odontostyle (11.0–12.5 vs 8.0–9.0 µm); lower c (33–43 vs 50–60) and higher c’ (0.76–1.0 vs 0.6–0.7) ratios, and longer tail (12–16 vs 8.0–9.0 µm). The present specimens also conform well with the Chinese specimens except in having anterior vulva position (V = 35.5–40.6 vs 42.0–43.5); slightly longer tail (12–16 vs 10–13 µm) and lower c ratio (33–43 vs 55–61). Goseco et al. (1974) in their revision of the genus Basirotyleptus restudied the type material of B. pini and they observed amphids are duplex, stirrup-shaped, but Siddiqi & Khan (1965) in their description mentioned that amphids are simple, stirrup-shaped. Whereas Baqri (1991) mentioned amphids as simple cup-shaped. The shape of amphids is apparently difficult to observe and in present specimens the amphids appeared as simple, stirrup-shaped. This species is recorded here for the first time from the Western Ghats.

In the presence of simple odontophore and anterior uterine sac, this species also comes close to Basirotyleptus basiri Jairajpuri, 1964 but differs in having outer and inner cuticle finely striated (vs distinctly striated), lip region offset by deep constriction (vs slight constriction) and shorter anterior uterine branch (two-fifths to two-thirds vs always more than midbody diameter long).

Figures

Fig. 2. Basirotyleptus pini Siddiqi & Khan, 1964, ♀ (AMU/ZD/NC/Basirotyleptus pini/1–3) (LM photographs). A–B. Anterior region. C. Anterior region showing amphid. D. Pharyngeal region. E–F. Pharyngeal bulb. G. Genital system. H. Vulval region. I. Posterior region. J. Posterior end. Scale bars =10 µm.