Pseudolella Cobb, 1920

Giri, Amalendu, Bera, Santosh Kumar, Das, Sujit, Mandal, Biplab & Ghorai, Sudipta Kumar, 2024, New distribution record: Pseudolella mangrovi Gagarin and Thanh, 2016 (free-living marine nematode) from Talsari Mangrove Mudflats, North-East Coast of India, Records of the Zoological Survey of India 124 (2), pp. 123-130 : 124-129

publication ID	https://doi.org/10.26515/rzsi/v124/i2/2024/172661
persistent identifier	https://treatment.plazi.org/id/03C13B0A-C068-FFDA-F9DC-0295A552F98D
treatment provided by	Felipe
scientific name	Pseudolella Cobb, 1920
status

Treatment

Genus- Pseudolella Cobb, 1920 View in CoL

Pseudolella mangrovi Gagarin and Thanh, 2016 View in CoL

Materials examined: Five specimens are examined(three male and two female): Regn. No. - Male: ZSI-HQ/ WN.4721/1; Female: ZSI-HQ/WN.4721/2.

Type locality and habitat: Intertidal mudflats of Subarnarekha river estuary, Talsari, Odisha, India , 21°35’50” N; 87°27’22” E. The mudflats are comprised primarily of clay with intermittent deposits of fine sand. This mixture creates a distinct substrate that supports a diverse range of marine life.

Measurement and abbreviation: All measurements are taken in µm (unit). But the ratio has no units. Curved lengths are measured along the middle line of the corresponding structure.

Abbreviations: a - total body length/ maximum body diameter, b - total body length/pharynx length, c - total body length/tail length, v’ - length of vulva from anterior end, v% - percentage of v’ in respect of total body length, abd - anal body diameter, cbd - corresponding body diameter, V arm - length of ventral arm of amphid.

Description: Male ( Figures 1 View Figure 1 , 2 View Figure 2 ; Table 1): This species exhibits a cylindrical, slender body, tapering anteriorly towards a rounded head and posteriorly towards a pointed tail. Finely striated body cuticle, visible under a light microscope. Six labial papillae are located at the anterior extremity. The diameter of the head in the lip region was measured to be 9-9.4 µm. Four cephalic sensilla, measuring 2.8-2.9 µm, are positioned immediately posterior to the anterior edge. Four sets of cervical setae, each consisting of two setae, are arranged sub-dorsally and sub-ventrally in a longitudinal row. Somatic setae are sparse and scattered. The bipartite stoma, 37.4-38.5 µm long, comprises a short, anterior cheilostome tapering towards the front and a long, cylindrical pharyngostome at the rear. Within the cheilostome, four tooth-like stout, sclerotized structures are positioned just above the odontia. The pharyngostome, measuring 29.9-30.8 µm, has cuticularized walls that expand at its base and bow sharply inward. The boundary between the cheilostome and pharyngostome is marked by two large odontia. In the labial region, a loop-shaped amphidial fovea, comprising a short dorsal branch terminating near the odontia level and a long ventral branch, 18.7-20 µm, reaching almost mid-stoma. The pharynx, occupying 8.6%-9.3% of the body length, is characterized by its short, cylindrical shape, muscular composition, and distinctive terminal bulb. A small, mascular, triangular cardia is positioned adjacent to the pharyngeal bulb. The renette gland is exceptionally large, measuring 37.8×15 µm -50.78×26.91 µm, and occupies 55.8%-80.6% of the corresponding body diameter. The renette gland is oval-shaped and located at the beginning of midgut. The excretory duct terminates at the odontia level, emptying through the excretory pore via a spacious cavity (1.1-1.2 times the stoma length) situated ventrally at the pharyngostomepharyngeal junction. Diorchic testes are arranged in tandem. The anterior testes commence 46.8-48.5% of the total body length from the anterior body end. The testes are asymmetrically positioned, with the anterior testes (74.6-134 µm) located on the right side of the intestine and the posterior testes (137-146 µm) on the left side. The paired spicules are equal in length (1.3 times of abd length), arcuate in shape, and feature double cephalation at the proximal end, tapering to a pointed tip distally. The paired gubernacula are equal, cuff-shaped with distinct dorsal apophysis, located adjacent to the distal one-third of the spicules. Tubular dorsal apophysis with rounded terminal head. Pre-cloacal supplements are absent. The tail is conical-cylindrical with a swollen tip, measuring approximately 4.7-5.9 times the abd length. Short, thin setae are arranged in single rows along the sub-dorsal and sub-ventral surfaces. Three caudal glands are located within the tail and exit through a terminal spinneret.

Female ( Figures 1 View Figure 1 , 3 View Figure 3 ; Table 1): The general morphology of female specimens is highly consistent, with uniformity observed in body shape, cuticle, labial papillae, cephalic and cervical setae, and amphid shape. A sexual dimorphism in body length is observed, with females being 938.3 µm and 964.4 µm longer than males. Female pharynx length exceeds that of males. Renette gland is exceptionally large, measuring (62.6×29.7 µm and 62.9×32.9 µm) and occupies approximately 78.4% and 82.5% of the corresponding body diameter. A sizable spacious cavity (44.3µm and 45.5µm) is located ventral to the pharyngostome-pharynx junction, terminating at the odontia level through an excretory pore. The ovary is didelphic and reflexed, without any mature eggs. The ovaries are positioned asymmetrically, with the anterior ovary located on the right side and the posterior ovary on the left side of the intestine. The anterior end of the anterior ovary is situated approximately 30.8% and

31.3% of the total body length from the anterior end. A short, thin-walled vagina connects to the uterus, while the vulva, lacking lips, is positioned midway along the body. Two ovoid vulvar glands flank the vagina, and brief spermathecae are likely situated between the ovary and uterus. The tail exhibits a conical-cylindrical shape with a swollen tip, measuring 5 and 5.8 times longer than abd. All measurements are taken in µm units. Ratio has no unit.

Data are taken from Gagarin and Thanh, 2016

Remarks ( Table 2): Pseudolella mangrovi Gagarin and Thanh, 2016 is characterized by comparatively long body length; finely striated cuticle; thin cephalic sensilla reaching 25.5%-31.2% of labial diameter; long, enlarged ventral branch of crook-shaped amphid, extending to mid-stoma; large and cylindrical stoma arched with expanded base with notable ventral odontia; slender pharynx with terminal bulb; excretory system with large Renette gland and spacious cavity posterior to the excretory pore; paired tandem testes; long, arcuate, double-headed spicules; small cuff-shaped gubernaculum with dorsal apophysis; paired reflexed ovary with no mature egg; long conical-cylindrical tail with swollen tip.

We report the first occurrence of P. mangrovi in India, confirming its original description by Gagarin and Thanh, 2016, except in having long body length (803.7-

964.4 µm vs 526-694 µm), greater value of ‘a’ and ‘b’ (‘a’:

24.9-32 vs 15-25; ‘b’: 10.7-12.4 vs 6.2-8.6), short pharynx length (71-77.9 µm vs 81-95 µm), long distance between pharynx base and vulva (363.4-387.4 µm vs 194-212 µm), significant separation between pharynx base and cloaca (593.4-611.3 µm vs 491-531 µm), long interval between vulva and anus (169-185 µm vs 317.9-323 µm), long tail length (77-95 µm vs 101.2-122 µm), relatively short spicule length compared to its anal body diameter (1.6-

1.7 fold vs 1.3 fold).