Basirotyleptus basiri 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 : 3-6

Basirotyleptus basiri Jairajpuri, 1964

Fig. 1 , Table 1

Basirotyleptus basiri Jairajpuri, 1964: 59–64 .

Trichonchium archium Siddiqi & Khan, 1964: 141–143 .

Basirotyleptus basiri – Siddiqi & Khan 1965: 23–31. — Furstenberg 1980: 154–155.

Material examined

INDIA – Kerala State • 7 ♀♀, 1 ♂; Kollam district, Ottakkal ; 8º59′24.0″ N, 77º00′28.8″ E; 5–15 cm depth; 2 Nov. 2017; soil samples collected from around the roots of grasses and shrubs (unidentified); slides reference number AMU/ZD/NC/ Basirotyleptus basiri /1–3 • 5 ♀♀; Ernakulum district, Kalady ; 11°03′40.7″ N, 76°32.7′23.8″ E; 5–15 cm depth; 27 Oct. 2017; soil samples collected from around the roots of grasses (unidentified); slides reference number AMU/ZD/NC/ Basirotyleptus basiri /4–6 • 8 ♀♀; Ernakulum district, Neriamangalam ; 10°03′50.4″ N, 76°41′38.4″ E; 5–15 cm depth; 29 Oct. 2017; soil samples collected from around the roots of pineapple ( Ananas comosus (L.) Merr.); slides reference number AMU/ZD/NC/ Basirotyleptus basiri /7–9.

Description

Female

Small sized nematodes, slightly curved ventrad upon fixation; body cylindrical, 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, 1.5–2.0 µm at midbody and 2.5–3.0 μm on tail. Outer cuticle thin, with transverse striations; inner layer thick, its outline loose, irregular, distinctly striated, with radial refractive elements. Lateral chords occupying about 28–35% of midbody diameter. Lateral body pores distinct; 1–3 in neck region; 2–3 at neck to vulval region and 4–7 at post-vulval region. Dorsal and ventral body pores indistinct. Lip region cap-like, offset by slight constriction, 2.0–2.4 times as wide as high or about two-fifths to one-half of the body diameter at neck base. Lips rounded, amalgamated, 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, needlelike, 1.2–1.5 times the lip region diameter long. Odontophore simple, sclerotized, about 1.0–1.1 times the odontostyle length. Guiding ring simple, refractive, at 1.0–1.3 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 15– 17% of total neck length. Nerve ring at 51–60% of neck length from anterior end. Cardia short, rounded to conoid, about one-fifth of the corresponding body diameter long.

Genital system monodelphic-opisthodelphic. Ovary reflexed, measuring 41–98 μm; oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally, measuring 45–81 μm, consisting of a slender distal portion and a well-developed pars dilatata. Oviduct-uterus junction marked by welldeveloped sphincter. Uterus short and tubular, measuring 21–36 μm. Anterior genital branch reduced to a simple sac, 1.0–1.4 times the midbody diameter long. Sperm cell absent. Vagina cylindrical, extending inwards, 9.5–11.5 μm or about one-half to three-fifths (50–61%) of midbody diameter; pars proximalis vaginae 5.5–7.5 × 4.5–6.0 μm, encircled by circular muscles; pars distalis vaginae long, 4.0–5.0 μm with slightly curved walls; pars refringens absent. Vulva apparently a transverse slit. Prerectum 2.0–3.2 and rectum 0.8–1.2 times anal body diameter long. Tail short, rounded to conoid, 0.8–1.0 times anal body diameter long, with a pair of caudal pores on each side.

Male

General morphology similar to that of female except for posterior region being more ventrally curved. Genital system diorchic, testes opposed, sperm cell spindle-shaped. In addition to adcloacal pair situated at 6 µm from cloacal aperture, there is single ventromedian supplement located at 25 μm from adcloacal pair, beyond the range of spicules. Spicules typically dorylaimoid, curved ventrad, slightly robust, 5.0 times as long as wide and 1.3 times as long as cloacal body diameter, dorsal contour regularly convex, ventral contour bearing a moderately developed hump and hollow, curvature 132º, head occupying 20% of total spicules length, median pieces 10.6 times as long as wide or occupying about 37% of the spicules maximum width, reaching the spicules tip, posterior end 2.5 μm wide. Lateral guiding pieces distinct, rod-like, about 5.0 times as long as wide or about one-fourth of the spicules length. Prerectum 3.0 and rectum 1.4 times cloacal body diameter long. Tail short rounded to conoid, about as long as the cloacal body diameter, with a pair of caudal pores on each side.

Remarks

Jairajpuri (1964) proposed the genus Basirotyleptus with B. basiri as its type species from Jorhat, Assam, India. Siddiqi & Khan (1964, 1965) recorded this species from Assam and Madhya Pradesh respectively. Furstenberg (1980) described this species from Malaysia, whereas, Shamim et al. (2014) from Pakistan. The morphometrics of present populations conform well with the type population except in having slightly lower c (35–47 vs 45–58) ratio and presence of male (vs absent). The present populations also conform well with Siddiqi & Khan (1964) population except in having slightly shorter body (0.45–0.54 vs 0.59–0.67 mm); lower b (4.0–4.9 vs 5.4–6.4) and c (36–47 vs 47–56) ratios and presence of male (vs absent). The present specimens also conform well with Madhya Pradesh population described by Siddiqi & Khan (1965) except in having short and robust body (0.45–0.54 vs 0.68–0.71 mm, a = 22–29 vs 29–31); slightly shorter odontostyle (10.5–12 vs 13–14 µm); lower b (4.0–4.9 vs 6.3–6.5) and c (36– 47 vs 58–61) ratios and smaller spicules (20 vs 25–26 µm). The morphometrics of present populations agree well with the Malaysia population except in having slightly longer odontostyle (10.5–12.0 vs 9.3–10.5 µm); longer rectum (11.5–20.0 vs 10–11 µm) and presence of male (vs absent). The present populations conform well with the Pakistan population except in having shorter body (0.45–0.54 vs 0.63–0.78 mm); lower b (4.0–4.9 vs 5.0–6.8), lower c (35–47 vs 56–69) ratios and slighter higher c’ (0.7–1.0 vs 0.5–0.7) ratio. These differences are considered here as intraspecific variability. This species is recorded here for the first time from the Western Ghats.

Figures

Fig. 1.Basirotyleptus basiriJairajpuri,1964(AMU/ZD/NC/ Basirotyleptusbasiri/1–3)(LMphotographs). A –B. Female, anterior region. C. Female, anterior region showing amphid. D. Female, pharyngeal region. E–F. Female, pharyngeal bulb. G–I. Female, genital system. J–K. Female, posterior region. L–M. Male, posterior end. Scale bars = 10 µm.