Goffartia phalacra Singh, Yousuf, Kumar & Ahmad, 2014

Tahseen, Qudsia & Mustaqim, Malka, 2015, A taxonomic review of the genus Goffartia Hirschmann, 1952 (Rhabditida: Diplogastridae) with a note on the relationship of congeners, Zootaxa 4034 (1) : -

Goffartia phalacra Singh, Yousuf, Kumar & Ahmad, 2014

( Figs. 1 F, 2E, 3F, 4–6)

Measurements. Table 1, 2

Description. Adult: Body small, 0.3–0.6 mm in length, very slender; almost straight or slightly arcuate upon fixation. Cuticle smooth in LM, subcuticle with very fine transverse striations; faint longitudinal striae observed in few specimens. Lateral fields usually faintly visible, occasionally differentiated by two wide-spaced lines. Lip region rounded, continuous with adjoining body contour; lips fused, amalgamated; labial sensilla papilliform, not discernible in LM. Amphidial apertures large, transverse slits with a median depression, amphidial pouches large,bowl-shaped or wine glass-shaped, and ca 65%–85% of the corresponding body diameter wide, located at 2.5–4.0 Μm from anterior end. Stoma small, tubular, 1.0–1.4 lip diameters long, 4.0–5.0 times longer than wide. Cheilostom not cuticularised, rod-shaped, with walls parallel or diverging posteriorly, narrower than gymnostom; gymnostom cuticularised about 40–50% of stoma length; metastegostom apparently unarmed and non-cuticularised, anisomorphic; telostegostom sloping, merging with pharyngeal lumen. Pharyngeal collar surrounding 50–60% of stoma; pharynx diplogastroid type, differentiated into 42–45 Μm long, cylindrical corpus; with set off, weakly swollen, ellipsoidal median bulb, and slightly narrower, 52–60 Μm long isthmus continuing into an elongate, somewhat pyriform, glandular basal bulb. Nerve ring encircling isthmus at ca 57–64% of pharyngeal length from anterior end. Secretory-excretory pore usually obscure, located at ca 85–90% of the pharyngeal length from anterior end in some specimens. Pharyngeal corpus smaller or ca 0.7–0.8 times longer than isthmus and basal bulb together. Body at pharyngeal end ca 2.2–3.2 lip diameters wide. Cardia small, conoid, 2.0–2.5 Μm long. Intestine granular, intestinal lumen with thick, refractive lining. Rectum 1.0–1.7 anal body diameters long. Tail long filiform. Phasmids minute pore-like, usually indiscernible.

Female: Reproductive system didelphic, amphidelphic, compact. Ovaries moderately developed, laterally reflexed; anterior ovary right and posterior on left side of intestine. Distal ends of ovaries not reaching beyond vulva. Oviduct proximally continuous with rounded spermatheca containing sperms. Intra-uterine egg not observed. Vagina thin-walled at right angle to longitudinal body axis, about 1/3 of vulval body diameter long. Vulva a small transverse slit. A pair of ovoid unicellular vaginal glands located anterior and posterior to vagina opening into each uterus.

Male: Similar to female in general morphology except in greater posterior curvature of body. Testis single, reflexed laterally, located on right side of intestine. Ejaculatory glands absent. Tail apparently divided into an anterior conical part and an abruptly narrowing posterior filamentous part terminating in a whip. Spicules free, slender having weak, rounded capitula, 1.6–1.7 times anal body diam. long. Gubernaculum fan-shaped, 40–53% of spicule length with the distal stem of fan cuticularised and the dorsal flap noncuticularised providing attachment for muscles and lateral distal sleeves surrounding the spicules. Genital papillae minute, comprising two precloacals and seven post-cloacals in a v1, v2 / v3 d, v4, ad, Ph, (v5 + v6, v7), pd configuration. v1 and v2 subventral, slightly spaced; v3 d lateral, slightly posterior to cloacal opening; v4 subventral, slightly posterior to the level of v3 d; ad subventral, located in posterior 1/3rd region of conoid part of tail; v5 occasionally surrounded by rudimentary cuticular flap, subventral ventrolateral and distant from the closely placed subventral v6 and v7 and a subdorsal pd.

Locality and habitat. Moist alluvial soil collected from the bank of pond at Sikandra Rao, Aligarh, Uttar Pradesh, India.

The species was originally reported ( Singh et al. 2014) from Sukhravali village, Ramghat Road, Aligarh, Uttar Pradesh and also from farmyard manure from district Baramulla, Jammu and Kashmir, India.

Voucher specimens. Twelve females and twelve males on slide No. NOSR-1–8 deposited in the Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh.

Salient characters. Cuticle with faint transverse striations often indiscernible under LM; longitudinal striations faintly visible with lateral fields demarcated, often with two lines; lip region rounded or dome-shaped with labial sensilla almost indiscernible; amphidial aperture transverse slit with a median depression, amphidial pouch wine glass-shaped; anterior part of pharynx smaller than posterior part; a pair of vaginal glands opening close to the junction of vagina and uteri; males with spicules cephalated, arcuate and gubernaculum fan-shaped having a non cuticularised dorsal flap and a median cuticularised stalk with lateral sleeves.

Remarks. The present population resembles G. phalacra Singh, Yousuf, Kumar & Ahmad, 2014 in most morphological and morphometric characters, however, some intraspecific differences could be observed that largely were due to different habitats or locations. The individuals of the present population show faint longitudinal striae in a few specimens whereas striae were not reported in the original population. The present population also differs on account of demarcated lateral fields with two faintly visible lines while lateral fields remained undifferentiated in original population of G. phalacra ( Singh et al. 2014) . The stoma in the latter population has been shown to be barrel-shaped with an arched gymnostom whereas the gymnostom in the present specimens shows parallel walls. In contrast to the short and isomorphic stegostom of original population, the stegostom in the present population appears to be slightly anisomorphic. Some other minor differences noted in the present population were the position of nerve ring (57–64% vs 55–60%) and the length of rectum in terms of anal body diameter (1.0–1.7 vs 1.2). The secretory-excretory pore in the present population remains largely obscure but in some specimens it is located at ca 85–90% of the pharynx length from anterior end. Contrary to the observations in original population of G. phalacra , intra-uterine eggs could not be found in present population. The gubernaculum as reported in the present population appears fan-shaped or keel-shaped with a median cuticularised stalk and small lateral sleeves. Finally the present population also differs on account of the genital papillae v4 and ad: the v4 pair is located close to the posterior lip of cloaca in contrast to its more posterior position in the originally-described specimens (2.5 anal body diameter posterior to cloaca) whereas the ad pair is located subventrally in present specimens in contrast to its lateral position in original population ( Singh et al. 2014).

S. No. Character Character state

1 Female body length body <0.6 mm (0),> 0.6 mm (1)

2 Cuticular transverse striations obscure (0), fine (1), medium (2), coarse (3) 3 Cuticular longitudinal striations absent (0), present (1)

4 Lateral fields not demarcated (0), demarcated (1), demarcated with lines (2) 5 Lip region rounded to dome-shaped (0), slightly truncate (1) 6 Labial sensilla papilliform (0), small setose (1), large setose (2) 7 Shape of amphidial aperture oval (0), rectangular (1), transverse slit with median depression (2) 8 Amphid size ¼ (0), 1/3–1/2 (1),>1/2 (2) of lip region width 9 Shape of stoma barrel-shaped (0), elongated (1), narrow tubular (2) 10 Adradial plates absent (0), prominent (1)

11 Posterior region of stoma simple (0), with one ring (1), with two parallel rings (2) 12 Dorsal metastegostomal tooth Indiscernible/absent (0), prominent (1) 13 Pharyngeal corpus + median bulb vs rest of smaller (0), larger (1), equal (2)

pharynx

14 Median bulb strongly (0), moderately (1), weakly (2) developed 15 Glandular part of pharynx slightly demarcated (0), not demarcated (1) from isthmus 16 Shape of glandular part rounded-ovoid (0), pyriform (1), elongated (2) 17 Excretory pore indistinct (0), conspicuous (1)

18 Vulva preequatorial (0), equatorial (1)

19 Female tail length ½–1/3 (0), 1/4–1/6 (1) of total body length 20 Spicule shape Slender, straight (0), slender arcuate (1), falcate (2),massive arcuate

(3)

21 Spicule size <20 Μm (0),>20 Μm (1)

22 Gubernaculum shape attenuated (0), blunt (1), hooked (2) proximally, fan-shaped (3) 23 Gubernaculum length vs spicule length up to 30% (0), 55% (1), 65% (2), 75% (3) 24 Position of papillae v1 and v2 closely spaced (0), slightly spaced (1), well spaced (2) 25 Position of papillae v5, v6, v7 all three (0), anterior two (1), posterior two (2) closely spaced; no

such grouping (3)

Characters 15 16 17 18 19 20 21 22 23 24 25 G. africana 0 0 0 1 0 1 0 2 3 0 0 G. heteroceri 0 1 0 0 0 2 0 0 1 0 1 G.filicaudata 0 1 0 1 0 2 0 2 2 0 2 G. phalacra 1 2 0 0 0 1 0 0 1 1 2 G. praepilata 0 0 1 1 1 2 1 0 0 0 3 G. variabilis 0 0 0 1 1 0 1 1 1 2 1 A. dendrophilus 0 1 1 1 1 3 1 0 3 0 0

Figures

FIGURE 1. Anterior body ends. A: Goffartia africana. B: G. filicaudata. C: G. heteroceri. D: G. variabilis. E: G. praepilata. F: G. phalacra. G: Female reproductive system in Goffartia sp. (Scale bar = 10 µm).