Basirotyleptus goaensis, Islam & Ahmad, 2022

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 : 34-39

Basirotyleptus goaensis sp. nov.

urn:lsid:zoobank.org:act:E0A280BC-CE80-43F7-8637-BDE34EC5017F

Figs 12–13 , Table 9

Diagnosis

Basirotyleptus goaensis sp. nov. is characterized by having 0.73–0.87 mm long body; lip region cap-like, offset by deep constriction; lips rounded, slightly angular, separated, inner part elevated; odontostyle 13.0–14.5 μm long, odontophore 15.0–17.5 μm long, total stylet length 28.5–31.0 μm; pharynx with a slender anterior part, expanding gradually into a short pyriform basal bulb, occupying about 16–18% of total neck length; female genital system monodelphic-opisthodelphic; anterior genital branch reduced to a simple sac, 24.5–46.0 µm or 1.0–1.6 times midbody diameter long, tail short, rounded to conoid, 0.7–0.8 times anal body diameter long.

Etymology

The new species is named Basirotyleptus goaensis sp. nov. because of its type locality Goa.

Material examined

Holotype INDIA • ♀; Goa State, South Goa district, Madgaon ; 15º09′03.5″ N, 74º01′05.5″ E; 5–15 cm depth; 19 April. 2016; roots of shrubs (unidentified); slide reference number AMU/ZD/NC/ Basirotyleptus goaensis /1.

Paratypes INDIA • 7 ♀♀; same collection data as for holotype; slides reference number AMU/ZD/NC/ Basirotyleptus goaensis /2–6 .

Type habitat and locality

Soil samples collected from around the roots of shrubs and forest trees (unidentified) from Madgaon, Goa State.

Description

Female

Small sized nematodes, slightly curved ventrad or open C-shaped upon fixation; body cylindrical, tapering gradually towards both extremities but more so towards the anterior end. Cuticle with two distinct layers, 1.0–1.5 µm thick at anterior region, 2.0–2.5 µm at midbody and 2.5–3.0 μm on tail. Outer cuticle thin, finely striated, with distinct rows of punctations; inner layer thick, finely striated, loose, its outline irregular, with distinct radial refractive elements but more so towards posterior region. Lateral chords occupying about 24–32% of midbody diameter. Lateral body pores distinct; 1–3 in neck region; 2–3 from pharyngeal base to vulva; 3–7 in post-vulval region. Dorsal and ventral body pores indistinct. Lip region cap-like, offset by deep constriction, 2.0–2.2 times as wide as high or about onethird of the body diameter at neck base. Lips rounded, slightly angular, separated, inner part elevated. Labial and cephalic papillae distinct and slightly raised above the labial contour. Amphids large, duplex, cup-shaped, their aperture about three-fifths to two-thirds as wide as lip region diameter. Stoma a long, slender truncate cone, slightly sclerotized in the perioral region. Odontostyle slender, solid, needlelike, 1.5–1.6 times the lip region diameter long. Odontophore simple, sclerotized, about 1.1–1.2 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 pyriform bulb, with a perceptible thickening at the posterior part of its inner lining, occupying about 16–18% of total neck length. Nerve ring at 56–60% of neck length from anterior end. Cardia rounded to conoid, about one-seventh to one-fifth of the corresponding body diameter long.

Genital system monodelphic-opisthodelphic. Ovary reflexed, measuring 73–167 μm; oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally, measuring 73–132 μm, consisting of a slender distal portion and a well-developed pars dilatata. Oviduct-uterus junction marked by distinct sphincter. Uterus short and wide tubular, measuring 36–52 μm. Anterior genital branch reduced to a simple sac, about 1.0–1.6 times midbody diameter long. Sperm cells present throughout the genital tract. Vagina cylindrical, extending inwards, 12–14 μm or about one-half (46–51%) of midbody diameter; pars proximalis vaginae 8.5–9.5 × 5.5–7.5 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 3.0–4.1 and rectum 0.8–1.1 times anal body diameter long. Tail short, rounded to conoid, 0.7–0.8 times anal body diameter long, with a pair of caudal pores on each side.

Male

Not found.

Remarks

In the presence of a comparatively long body, simple odontophore and presence of long anterior uterine sac, the new species comes close to B. upicus Ahmad & Jairajpuri 1979 ; B. rotundicaudatus ( Khan, 1987) ; B. basiri Jairajpuri, 1964 and B. pini Siddiqi & Khan, 1965 but differs from B. upicus in the presence of distinct punctations on cuticle (vs punctations absent); lip region with differently shaped amphid (duplex, cup-shaped vs simple, cup-shaped); guiding ring slightly more posterior (1.2–1.3 times vs one lip region diameter from anterior end); longer total stylet and odontophore (stylet 28.5–31.0 vs 25–27 µm, odontophore 15.0–17.5 vs 11–13 µm); longer pharyngeal bulb (22.5–26.0 vs 20–22 µm or 16–18 vs 15–16% of total neck length); slightly anterior vulva position (V = 36–39 vs 39–42); longer prerectum (52–73 vs 45–50 µm or 3.0–4.1 vs 2.5–2.7 times anal body diameter); shorter tail (12–15 vs 17–20 µm, c = 51–62 vs 41–48) and absence of male (vs present).

From B. rotundicaudatus , the new species differs in having differently shaped amphids (duplex, cupshaped vs simple, cup-shaped), absence of hypodermal glands (vs present); pharyngeal expansion gradual (vs abrupt) and longer pharyngeal bulb (22.5–26.0 vs 19 µm); absence of flanges at base of odontophore (vs small flanges present); shorter anterior uterine sac (24.5–46.0 vs 65 µm); higher c (51–62 vs 42–47) ratio and absence of male (vs male present).

From B. basiri , the new species differs in having longer body (L = 0.73–0.87 vs 0.45–0.71 mm), presence of punctations on cuticle (vs punctations absent); lip region offset by deep constriction (vs slight constriction); differently shaped amphid (duplex, cup-shaped vs simple, stirrup-shaped); wider lip region (8.5–10.0 vs 8.0–8.5 µm); longer total stylet length and odontophore (28.5–31.0 vs 22.0– 24.5 µm, 15.0–17.5 vs 11.5–13 µm); longer pharyngeal bulb (22.5–26.5 vs 16.5–20.5 µm) and absence of male (vs present).

From B. pini , the new species differs in having a longer body (L = 0.73–0.87 vs 0.49–0.62 mm), presence of punctations on cuticle (vs punctations absent); longer odontostyle (13.0–14.5 vs 11.0–12.5 µm); longer pharyngeal bulb (22.5–26.5 vs 17–20.5 µm); longer anterior uterine sac (24.5–46 vs 8.0–18 µm or 1.0–1.6 times vs less than one midbody diameter long).

Figures

Fig. 12. Basirotyleptus goaensis sp. nov., ♀. A–E, G. Paratypes (AMU/ZD/NC/Basirotyleptus goaensis/2–6). A. Paratype 7. B, D, G. Paratype 4. C. Paratype 2. E. Paratype 1. F. Holotype (AMU/ ZD/NC/Basirotyleptus goaensis/1). A. Entire specimen. B. Anterior region. C. Anterior region showing amphid. D. Pharyngeal region. E. Pharyngeal bulb. F. Genital system. G. Posterior region.

Fig. 13. Basirotyleptus goaensis sp. nov., ♀ (LM photographs). A–B, D–M. Paratypes (AMU/ZD/NC/ Basirotyleptus goaensis/2–6). A, D–F, H, K. Paratype 1. B, G, J. Paratype 2. C. Holotype (AMU/ ZD/NC/Basirotyleptus goaensis/1). I. Paratype 4. L. Paratype 5. M. Paratype 3. A–B. Anterior region. C–D. Anterior region showing amphid.E. Pharyngeal region.F–G. Pharyngeal bulb.H. Cuticle showing punctations. I–K. Genital system. L. Posterior region. M. Posterior end. Scale bars: A–D, F–H, J–K, M = 10 µm; E, I = 20 µm.