Eudorylaimus blisterocaudatus Liang, Islam, Du, Li, Liang, Ahmad, Zhang, Mahamood, Alhewairini & Li, 2025, sp. nov.
Creators: name: Liang, Siwei
name: Islam, Md Niraul
name: Du, Xiaofang
name: Li, Ying bin
name: Liang, Wenju
name: Ahmad, Wasim
name: Zhang, Xiaoke
name: Mahamood, Mohammad
name: Alhewairini, Saleh
name: Li, Qi
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Enoplea
Dorylaimida
Dorylaimidae
Eudorylaimus
Eudorylaimus blisterocaudatus

description: Eudorylaimus blisterocaudatus sp. nov.
Figs 4, 5, 6, Tables 3, 4
Type material.
Holotype • China (IAE / NC / EU / E. blisterocaudatus / 1), Liaoning Province, Huludao City, Xingcheng; 40.860423°N, 120.95638°E; soil samples collected from around the roots of grasses (unidentified). Paratypes • China (4 ♀ / 4 ♂; IAE / NC / EU / E. blisterocaudatus / 2-5), same data as holotype. (2 ♀ IAE / NC / EU / E. blisterocaudatus / 6), Liaoning Province, Yingkou City, Gaizhou; 40.475832°N, 122.421428°E; soil samples collected from around the roots of Poplar (Populus L.).
Diagnosis.
Eudorylaimus blisterocaudatus sp. nov. is characterized by its 1.0– 1.3 mm long slender body; lip region offset by constriction and 15–17 μm broad; odontostyle 18–19 μm with an aperture ~ 37–40 % of its length, odontophore 24–28 μm long, 1.3–1.5 times the odontostyle length, total stylet length 42–46 μm; pharynx 300–339 μm long, pharyngeal expansion 129–156 μm or ~ 41–47 % of the total pharyngeal length; cardia long 17–26 μm or 0.42–0.58 times the corresponding body diameter long; female genital system didelphic-amphidelphic, uterus long, well-differentiated; V = 59–63 %; tail short (35–49 μm, c = 23.3–34.7, c’ = 1.2–1.7), conoid with rounded to sub-clavate terminus, and bearing series of blisters (thickening) on the ventral side, hyaline part 20–33 % of its length; males with 39–45 µm long spicules, lateral guiding pieces rod-like, slightly curved ventrally, bifurcated with claw-like distal end, and 6–8 irregularly spaced ventromedian supplements with hiatus.
Description.
Female. Slender nematodes of medium-sized, 1.0– 1.3 mm long body; curved ventrally or open C-shaped upon fixation. Body cylindrical, tapering gradually towards both extremities but more so towards the posterior region. Cuticle with two distinct layers, 1.5–2.0 μm thick at the anterior region, 2.5–4.0 μm at midbody, and 4.0–5.0 μm on tail. Outer cuticle smooth or finely striated, inner layer thin with fine transverse striations. Lateral, dorsal, and ventral body pores indistinct. Lateral chords 13–15 μm at midbody, occupying ~ 1 / 3 (28–34 %) of the corresponding body diameter. Lip region offset from the body by constriction, 2.2–2.6 times as wide as high or ~ 1 / 3 to 2 / 5 (32–40 %) of the body diameter at the pharyngeal base. Lips angular, separated. Amphidial fovea cup-shaped, aperture slit-like, 8.0–10 μm wide or occupying ~ 1 / 2 to 3 / 5 (50–62 %) of lip region diameter. Cheilostom a truncate cone. Odontostyle typical dorylaimid in shape, 6.0–7.4 times as long as wide, 1.1–1.2 times the lip region diameter long or 1.3–1.7 % of total body length, its aperture 7.0–7.5 μm or ~ 2 / 5 (37–40 %) of its length. Odontophore linear, rod-like, 1.3–1.5 times the odontostyle length. Guiding ring simple, at 0.5–0.6 times lip region diameter from anterior end. Pharynx consisting of a weakly muscular anterior part, expanding gradually into a cylindroid basal part, occupying ~ 41–47 % of total neck length; expanded part of the pharynx 5.1–6.6 times as long as wide, 2.8–3.8 times body diameter at neck base. Pharyngeal gland nuclei and their orifices are located as follows: DO = 57–61, DN = 59–65, DO – DN = 2.3–4.2, S 1 N 1 = 71–76, S 1 N 2 = 77–81, S 2 N = 87–89, S 2 O = 88–91. Nerve ring encircling the pharynx at 34–39 % of neck length from the anterior end. Cardia rounded to conoid, ~ 2 / 5 to 3 / 5 (42–58 %) of the corresponding body diameter long, its junction with pharyngeal base apparently surrounded by cardiac disc. Genital system didelphic-amphidelphic; both the genital branches almost equally developed. Anterior genital branch 14.3–26.8 % and the posterior genital branch 15.3–26.3 % of body length. Ovaries reflexed, not reaching the oviduct-uterus junction; measuring 76–105 μm or 1.7–2.5 (anterior) and 82–110 μm or 1.5–2.2 (posterior) times the corresponding body diameter long; oocytes arranged in a single row except near the distal end. Oviduct joining the ovaries sub-terminally, measuring 82–110 μm or 1.5–2.2 (anterior) and 57–98 μm or 1.0–2.3 (posterior) times the corresponding body diameter long; consisting of a slender distal portion and a well-developed pars dilatata. Oviduct-uterus junction marked by the well-developed sphincter. Uterus well-differentiated, tripartite, the proximal part short and well-developed muscular, the median part also short, wider than the proximal part, the distal part comparatively long, somewhat spheroid, measuring 63–170 μm or 1.4–3.8 (anterior) and 65–124 μm or 1.3–2.8 (posterior) times the corresponding body diameter long. Vagina extending inwards, 17–22 μm or ~ 2 / 5 to 1 / 2 (38–46 %) midbody diameter; pars proximalis 12–15 × 8.0–11 μm, with somewhat sigmoid wall encircled by circular muscles; pars refringens with two small triangular-shaped sclerotized pieces, measuring 5–6 × 3–4 μm and the combined width 7.5–9 μm; pars distalis 2.0–3.0 μm. Vulva a transverse slit. Sperm cells present (n = 4). Prerectum 1.1–3.0 and rectum 1.0–1.3 times the anal body diameter long, a distinct blind sac extending posteriorly to the prerectum-rectum junction (Fig. 6 D, E). Tail short, dorsally convex, conoid, almost straight or distal part slightly bent ventrally with a rounded to sub-clavate terminus, 1.3–1.6 times anal body diameter long; with characteristic series of thickening (blisters) on the ventral side of tail (Fig. 6 C – E, G); hyaline portion of tail perceptible, ~ 1 / 5 to 1 / 3 of total tail length with a pair of caudal pores on dorsal side.
Male. General morphology similar to that of the female except for the posterior region being more ventrally curved. Genital system diorchic, testes opposed, sperm cells spindle-shaped, 6.0–8.0 μm long. In addition to the adcloacal pair, situated at 7–8 µm from the cloacal aperture, there are six to eight irregularly spaced ventromedian supplements, the first ventromedian supplement located outside the range of spicules, 35–51 μm from the adcloacal pair. Spicules typically dorylaimoid, curved ventrad, relatively robust, 4.3–5.0 times as long as wide and 1.2–1.5 times as long as body diameter at the level of cloacal aperture, dorsal contour regularly convex, ventral contour bearing a moderately developed hump, curvature of 120–127 °. Head occupying 16–21 % of total spicules length, its dorsal side longer than ventral side, both sides slightly curved. Median pieces 9.6–10 times as long as wide or occupying ~ 33–38 % of the spicules’ maximum width, reaching the spicule tip, posterior end 3–4 μm wide. Lateral guiding pieces distinct, rod-like, slightly curved ventrally, bifurcated with claw-like distal end, ~ 4.8–6.0 times as long as wide or ~ 1 / 3 (30–33 %) of the spicules’ length. Prerectum 1.9–4.4 and rectum 1.3–1.5 times the cloacal body diameter long. Tail short, dorsally convex, conoid, almost straight or distal part slightly bent ventrally with a rounded to sub-clavate terminus, 1.3–1.5 times anal body diameter long; with characteristic series of thickening (blisters) on ventral side; hyaline portion of tail perceptible, ~ 1 / 3 of total tail length long with a pair of caudal pores on dorsal side.
Etymology.
The new species is named Eudorylaimus blisterocaudatus because of the presence of blisters in the caudal region.
Remarks.
With the presence of blisters on tail, the new species is morphologically close to E. caudatus Mushtaq & Ahmad, 2006; E. pectinatus Mukhina, 1970; E. pussulosus Andrássy, 1991; E. coniceps Loof, 1975 and E. schraederi Altherr, 1974 but differs from former in having a longer body size (L = 1.0–1.3 vs 0.79–0.93 mm); broader (15–17 vs 10.4–12.5 µm and 2.0–2.3 vs 2.2–2.6 times as long as high) and differently shaped lip region (lips distinctly separated, strongly angular with wider expansion vs less separated, moderately angular with less expansion) and wider amphidial aperture (8.0–10 vs 5.0–7.5 µm); long and slender odontostyle (18–19 vs 11–14 µm or 6.0–7.4 vs 5.0–6.5 times as long as wide), longer odontophore (24–28 vs 16.5–18.5 µm) and total stylet length (42–46 vs 28–32.5 µm); longer pharyngeal length and its expansion (300–339 vs 210–291 µm, 129–156 vs 99–122 µm), longer cardia (17–26 vs 11–15 µm); longer tail length (35–49 vs 25.5–33 µm) and longer spicules (39–45 vs 32 µm). The new species differs from E. pectinatus in having a pre-rectal blind sac (vs pre-rectal blind sac absent); differently shaped tail (tail dorsally convex-conoid conoid, slightly bent ventrally with rounded terminus vs tail dorsally convex-conoid to sub digitate with acute terminus), ventral surface of the tail not pectinate (vs ventral surface of tail pectinate) and longer spicules (39–45 vs 32 µm). From E. pussulosus in its more posteriorly vulval position (V = 59–63 vs 48–55 %); presence of pre-rectal blind sac (vs absence); smaller spicules (39–45 vs 47–49 µm), fewer ventromedian supplements (6–8 vs 17), first one beginning outside the range of spicules (vs within the range of spicules) and differently shaped tail (tail conoid, dorsally convex, straight to slightly bent ventrally vs dorsally concave, straight to slightly bent dorsally). From E. coniceps in its smaller body size (L = 1.0–1.3 vs 1.6–2.6 mm); differently shaped lip region (lip region offset by distinct constriction, lips angular, separated vs offset by slight depression, lips amalgamated); lower c value (23–35 vs 41–54); posteriorly vulval position (V = 59–63 vs 42–49 %); presence of pre-rectal blind sac (vs blind sac absent); smaller spicules (39–45 vs 60–80 µm) and differently shaped tail terminus (tail tip rounded to sub-acute vs tail tip acute, pointed). From E. schraederi in having a shorter and robust body (L = 1.0–1.3 vs 1.6–2.6 mm, a = 22–30 vs 44–53), shorter tail (c’ = 1.3–1.6 vs 4.4), comparatively shorter odontostyle (18–19 vs 20 µm); posteriorly vulval position (V = 59–63 vs 51 %); presence of pre-rectal blind sac (vs absence) and presence of male (vs male absent).
In the presence of blisters on the ventral cuticle of the tail, the new species is also similar to E. maritus Andrássy, 1959 but differs in having a shorter and robust body (L = 1.0–1.3 vs 2.0– 2.3 mm, a = 22–30 vs 30–37), narrower lip region offset by constriction (15–17 vs 19–21 µm, offset by depression), shorter odontostyle (18–19 vs 24–28 µm); lower b (3.5–3.9 vs 4.0–5.0) and c (23–35 vs 40–43) values, and posterior vulval position (V = 59–63 vs 48–50 %).
In its medium-sized body and the presence of pre-rectal blind sac, the new species is similar to E. productus (Thorne & Swanger, 1936) Andrássy, 1959 and E. bombilectus Andrássy, 1962 but differs from former in having a slender body (a = 22–30 vs 18.9–22.6), comparatively wider lip region offset by constriction (15–17 vs 13–14.5 µm, lip region continuous or offset by slight depression); longer odontostyle (18–19 vs 14–15 µm) and odontophore (24–28 vs 19–24 µm); comparatively posterior vulval position (V = 59–63 vs 52–55 %); presence of blisters on the ventral cuticle of the tail (vs blisters absent) and comparatively smaller spicules (39–45 vs 45–50 µm).
The new species differs from E. bombilectus in its lip region offset by constriction (vs depression), longer odontostyle (18–19 vs 14 µm); comparatively lower b value (3.5–3.9 vs 4.2–4.4) in female; comparatively posterior vulval position (V = 59–63 vs 52–54 %), cuticle near vulva simple, without any sclerotization (vs finely wrinkled near vulva); presence of blisters on the ventral side of the tail (vs blisters absent) and fewer numbers of ventromedian supplements (6–8 vs 10–12).
description: Published as part of Liang, Siwei, Islam, Md Niraul, Du, Xiaofang, Li, Ying bin, Liang, Wenju, Ahmad, Wasim, Zhang, Xiaoke, Mahamood, Mohammad, Alhewairini, Saleh & Li, Qi, 2025, Two new and two known species of the genus Eudorylaimus Andrássy, 1959 (Nematoda, Dorylaimoidea, Qudsianematidae) from Northeast China, pp. 41-74 in ZooKeys 1238 on pages 41-74, DOI: 10.3897/zookeys.1238.138550