Haliplectus sandspitensis, Waheed & Decraemer & Kazi & Tariq & Iqbal, 2024

Waheed, Samina, Decraemer, Wilfrida, Kazi, Nasira, Tariq, Rajput Muhammed & Iqbal, Erum, 2024, Description of two new species of Haliplectus Cobb, 1913 (Nematoda, Plectida, Haliplectidae) from mangrove areas of Sandspit backwater, Karachi, Pakistan, Zootaxa 5468 (1), pp. 154-166 : 160-163

Haliplectus sandspitensis n. sp.

( Figures 3 and 4 , Table 1 )

Material studied. Sixteen females. Glycerin slides.

Type material. Holotype female: PAK/ NNRC / N326 , L: 1115 µm.

Female paratypes: PAK/ NNRC / N327 , L: 1108 µm; PAK/ NNRC / N328 , L: 1269 µm; PAK/ NNRC / N329 , L: 1114 µm, PAK/ NNRC / N330 , L: 1202 µm; PAK/ NNRC / N331 , L: 1150 µm; PAK/ NNRC / N332 , L: 1155 µm; PAK/ NNRC / N333 , L: 1116 µm; PAK/ NNRC / N334 , L: 1108 µm; PAK/ NNRC / N335 , L: 1080 µm; PAK/ NNRC / N336 , L: 1185 µm; PAK/ NNRC / N337 , L: 1092 µm; PAK/ NNRC / N338 , L: 1068 µm; PAK/ NNRC / N339 , L: 1140 µm; PAK/ NNRC / N340 , L: 1170 µm; PAK/ NNRC / N341 , L: 1232 µm .

Type locality and habitat. Sandspit backwater, Karachi, Sindh, Pakistan. The area is dominated with the dense vegetation of mangrove ( Avicennia marina ). The specimens were found in muddy-sand with algal matter.

Type specimens. Slides of holotype and paratype specimens are deposited in the Nematode Collection of National Nematological Research Centre , University of Karachi, Karachi-75270, Pakistan.

Etymology. The name refers to the locality from where the samples were collected.

Description. Females: Body elongated, cylindrical, tapering at both ends, irregularly curved upon relaxed. Cephalic region low, hemispherical. Cuticle prominent, thick 1–2 µm wide, strongly annulated, annules smooth, about 2–3 µm wide at mid body and 1–2 µm wide towards head and tail. Body pores not observed. Labial and cephalic sensilla indistinct. Lips amalgamated, body diameter at level of posterior esophagus about 3–4 times cephalic region width.Amphidial fovea circular, 3–6 µm long, 5–6 µm wide, 40–41% of corresponding body diameter, situated 1.1– 1.3 times head width. Stoma elongate tubular, 6.5–7.1 times head width, metastom with about 1–2 µm wide lumen, extending to the median esophageal bulb. Stoma without teeth or denticles. Esophagus muscular, with differentiation consisting of narrow procorpus and somewhat wider fusiform median bulb (metacorpus) 14–21 µm long and 8–13 µm wide, slightly narrower isthmus surrounded by nerve ring, located at 56–64% of esophageal length, and a large well developed distinct spherical, muscular, bipartite basal bulb 24–30 µm long and 20–31 µm wide with striated valve plates. Longitudinal oval valvula about 17–23 µm long and 5–12 µm wide. Esophageal glands and their orifices indistinct. Cardia cylindroid, large, distinct with no associated glands. Intestine with distinct lumen throughout, attached to the basal region of cardia. Rectum opens through a distinct anus, 12–24 µm long or 0.5–0.8 anal body width long. Three rectal glands 6–7 µm or 0.2 anal body width long present at junction of intestine and rectum. Prerectum not observed.

Vulva a short transverse slit like opening, surrounded by thickened cuticle, lips not raised above body surface, situated at 436–568 µm from anterior end. Vagina straight, weakly muscular. Reproductive system didelphic, opposed ovaries reflexed with 7–10 oocytes. Anterior branch usually longer (90–136 µm) than posterior branch (60–116 µm). Tail elongated, conoid, 1.4–2.2 times anal body width long. Three caudal glands distinct, tandem with well defined spinneret.

Males. Not found.

Diagnosis. H. sandspitensis n. sp. is characterized by more than 1 mm body length (1.0– 1.2 mm); annulated cuticle; amphidial fovea at 8–12 µm from the anterior end; bipartite basal bulb with striated valve plates; didelphic reproductive system, with the vulva at 40–47% of body length and tail elongated, conoid, 1.4–2.2 times anal body width long.

Differential diagnosis. The new species is similar to H. bidenticulatus Heyns & Swart, 1993 in body length (1.0–1.2 vs 1.1–1.4 mm); tail length (40–50 vs 41–57 µm) and didelphic reproductive system but differs from it in higher value of ‘a’ ratio (24.6–41.3 vs 22–24); head width (7–9 vs 12–14 µm); shorter body width (27–40 vs 50–58 µm); V% (40.4–47.0 vs 46.9–56.3); shorter rectum (12–24 vs 30–33 µm); stoma without denticles vs stoma with two small denticles; bipartite esophageal basal bulb with striated valve plates vs bipartite basal bulb with unstriated valve plates.

The new species also resembles H. pakistanensis Shahina, Siddiqi & Nasira, 2014 in body length (1.0–1.2 vs 1.1–1.3 mm); tail length (40–50 vs 46–54 µm) and having didelphic reproductive system but differs from it by smaller value of ‘b’ ratio (8.3–10.6 vs 11.3–13.9); head width (7–9 vs 9–11 µm); longer stoma length (46–64 vs 32–42 µm); shorter cardia length (8–16 vs 16–18 µm); smaller anal body width (22–29 vs 30–36 µm) and bipartite esophageal basal bulb with striated valve plates vs bipartite basal bulb with unstriated valve plates.

Figures

FIGURE 3. Haliplectus sandspitensis n. sp. Female: A. Entire body, B. Anterior region and amphidial fovea, C. Anterior and esophageal region, D. Tail region and E. Reproductive system.

FIGURE 4. Haliplectus sandspitensis n. sp. Female:A. Entire body, B. Esophageal region, C. Anterior region, D. Reproductive system, E. Vulval region, F. Basal bulb with cardia and G–H. Tail region (Scale A=100µm; B–H = 20µm).