Haliplectus shahinae, 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 : 156-160

Haliplectus shahinae n. sp.

( Figures 1 and 2 , Table 1 )

Material studied. Five females. Glycerin slides.

Type material. Holotype female: PAK/ NNRC / N321 , L: 408 µm.

Female paratypes: PAK/ NNRC / N322 , L: 428 µm; PAK/ NNRC / N323 , L: 440 µm; PAK/ NNRC / N324 , L: 445 µm; PAK/ NNRC / N325 , L: 440 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 species is named in honour of late Prof. Dr. Shahina Fayyaz, University of Karachi, Pakistan, for her contributions to the nematode taxonomy.

Description. Females: Body posture C-shaped in heated relaxed specimens, tapering at both ends. Cephalic region low, hemispherical. Cuticle prominent, thick 1–2 µm wide, strongly annulated, annules smooth 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 end about 2.7–3.0 times head width. Amphidial fovea circular, 3 µm long and 3 µm wide, 21–33% of corresponding body diameter. Stoma elongated tubular 28–32 µm long, 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) 9–10 µm long and 6–7 µm wide, slightly narrower isthmus surrounded by nerve ring, located at 60–70% of esophageal length, and a large well developed distinct spherical, muscular, bipartite basal bulb 16–20 µm long and 14–16 µm wide with unstriated valve plates. Esophageal glands and their orifices indistinct. Excretory pore not observed. Cardia distinct, large, cylindroid, with no associate glands. Intestine with large to medium sized cells with wide and distinct lumen throughout, attached to the basal region of cardia. Rectum opens through a distinct anus, 9–12 µm long or 0.5–0.6 anal body width long with three rectal glands seen proximally, 6–7 µm or 0.3 anal body width long. Prerectum not observed.

Vulva a short transverse slit like opening, slightly sclerotized, lips not raised above body surface, situated at 220–254 µm from anterior end. Vagina straight, not muscular, surrounded by weakly developed constrictor muscles. Reproductive system mono-prodelphic, with 18–26 µm long post-uterine sac, ovary reflexed with 7–10 oocytes. Spermatheca not observed. Tail short conoid, straight, 1.5–1.8 times anal body width long. Caudal glands three, tandem, distinct. Spinneret well defined.

Males. Not found.

Diagnosis. H. shahinae n. sp. is characterized by its comparatively shorter body length (0.40–0.44 mm); annulated cuticle; amphidial fovea at 6–9 µm from the anterior end; bipartite basal bulb with unstriated valve plates; reproductive system mono-prodelphic with reflexed ovary, presence of post uterine sac and vulva at 52–57% of body length and tail short conoid, straight, 1.5–1.8 times anal body width long.

Differential diagnosis. The new species is similar to H. minimus Gerlach, 1967 in ‘a’ and ‘b’ ratios (13.8–16.2 vs 15.8; 6.2–7.8 vs 7.3, respectively). However, compared to the description of H. minimus by Gerlach (1967), H. shahinae n. sp. can be distinguished by the relatively shorter tail length (27–31 vs 37 µm; c= 14.1–15.1 vs 10.7); the posterior location of the vulva to the body length (52–57 vs 48%); striations on basal bulb valve plates absent vs striated basal bulb; reproductive system mono-prodelphic vs reproductive system didelphic. The new species also resembles H. monodelphis Shahina, Siddiqi & Nasira, 2014 in having a mono-prodelphic reproductive system; similar stoma length (28–32 vs 26–34 µm); V% (52–57 vs 53–57) and anal body width (17–18 vs 17–19 µm) but differs from it in shorter body and tail length (0.40–0.44 vs 0.49–0.52 mm; 27–31 vs 34–40 µm, respectively); body slightly wider (27–31 vs 26–27 µm, a= 13.8–16.2 vs 18–19); shorter esophagus (57–70 vs 70–76 µm) and bipartite basal bulb vs monopartite basal bulb.

H. shahinae n. sp. is the second species having mono-prodelphic reproductive system within the genus, while the first species having mono-prodelphic reproductive system was H. monodelphis described by Shahina et al. (2014) also from Pakistan.

Figures

FIGURE 1. Haliplectus shahinae n. sp. Female: A. Anterior and esophageal region, B. Anterior region and amphidial fovea, C. Reproductive system, D. Tail region and E. Entire body.

FIGURE 2. Haliplectus shahinae n. sp. Female: A. Esophageal region, B. Anterior region, C–D. Reproductive system, E–F. Basal bulb with cardia, G. Vulval region, H, J. Tail region and I. Entire body (A–H, J = 20µm; I = 30 µm).