Tantunema intermedium ( Peña-Santiago and Coomans 1996 ) Andrássy, 2009

Ahad, Sumaya & Ahmad, Wasim, 2016, Taxonomy of the genus Tantunema Siddiqi, 1982 (Dorylaimida: Tylencholaimidae) with description of one new and two known species, Journal of Natural History 50 (27), pp. 1669-1685 : 3-6

Tantunema intermedium ( Peña-Santiago and Coomans 1996) Andrássy, 2009

( Figures 1 and 2 ; Table 2 )

Description

Female. Small sized nematodes, slightly curved upon fixation; body cylindrical tapering gradually towards both the extremities. Cuticle with two distinct layers, 1.5 – 2.0 μm thick at midbody and 2 μm on tail. Outer cuticle finely striated; inner layer thick with indistinct radial refractive elements. Lateral chords occupying about 28 – 33% of the midbody diameter. Lateral, dorsal and ventral body pores indistinct. Lip region rather flattened, low, set off by a shallow constriction, 2.3 – 3.5 times as wide as high or about one-third of the body diameter at neck base; lips rounded and amalgamated, with their inner part scarcely elevated. A weakly developed post-labial sclerotization present. Amphids cup-shaped, their aperture 28 – 33% of lip region diameter. Cheilostome a truncate cone. Odontostyle 1.0 – 1.1 times the lip region diameter long and its aperture about one-quarter of the odontostyle length. Odontophore rod-like with slight basal thickening, 1.0 – 1.2 times the odontostyle length. Guiding ring simple, refractive, at 0.5 – 0.8 times lip region diameter from anterior end. Pharynx consists of a slender and weakly muscular anterior part, expanding abruptly into a cylindrical basal expansion, with thick-walled lumen, occupying about 36 – 42% of the total neck length. Pharyngeal gland nuclei and their orifices located as follows: DO = 60 – 70, DN = 63 – 72, DO – DN = 3.2 – 3.3, S1N1 = 74 – 84, S1N2 = 76 – 85, S2N = 90 – 91, S2O = 90 – 91. Cardia short, rounded-hemispheroid, about one-sixth to one-third of the corresponding body diameter long. Nerve ring located at 39 – 42% of neck length from anterior region. Genital system mono-opisthodelphic. Ovary reflexed, measuring 40 – 79 µm long; oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally. Oviduct separated from the uterus by a narrowing but no apparent sphincter seen. Anterior genital branch completely absent. Vagina directed backward; pars proximalis vaginae 4 – 6 µm long, its wall encircled by muscles; pars distalis vaginae short, 1.5 µm long with slightly curved walls; pars refringens absent. Vulva apparently a transverse slit. Prerectum 1.8 – 3.3 and rectum 0.8 – 1.1 times anal body diameter long. Tail cylindroid, 1.1 – 1.4 anal body diameter long, with indistinct caudal pores.

Male. Not found.

Habitat and locality. From soil around the roots of bushy trees and herbs of Naqvi Park, Aligarh, India.

Remarks. Peña-Santiago and Coomans (1996) described this species as Tylencholaimus intermedius from Spain. Ahmad and Araki (2003), Ahmad et al. (2009) and Ahmad and Baniyamuddin (2010) re-described this species from Japan, Korea and Singapore, respectively. The morphometrics of the present population corresponds well with the type population, except for having comparatively longer odontophore (8 – 9 µm versus 7.0 – 7.5 µm). The present population also conforms well to the population described by Ahmad and Araki (2003) from Japan except in the absence of hemizonid at the level of nerve ring (versus present at the level of nerve ring) and slightly higher ‘ c ’ ratio (versus 30, 31). It also agrees fairly well with the Korean as well as Singapore population. Peña-Santiago (2008) synonymized Opisthotylencholaimus karnataki Dhanam and Jairajpuri, 1999 with Tylencholaimus intermedius . The present population also corresponds well with this population recorded from Karnataka, India except for having slightly lower ‘ a ’ ratio (versus 31 – 35) and cup-shaped amphids (versus conical). Andrássy (2009) rightly transferred this species to the genus Tantunema because of the presence of a small amphid aperture, a weakly developed post-labial sclerotization and the absence of basal knobs in odontophore.

Figures

Figure 1. Tantunema intermedium (Peña-Santiago and Coomans, 1996) Andrássy, 2009. A. Entire female; B. Anterior region; C. Anterior end showing amphid; D. Pharyngeal region; E. Pharyngeal bulb; F. Female genital system; G. Female posterior region.

Figure 2. Tylencholaimus intermedius Peña-Santiago and Coomans, 1996. A. Anterior region; B. Anterior end showing amphid; C. Pharyngeal bulb; D. Female genital system; E. Vulval region; F. Female posterior region. A, B, E, = 10 μm; D, C, F, = 20 μm.

Tables

Table 2. Measurements of Tantunema intermedium (Peña-Santiago & Coomans, 1996) Andrássy, 2009 and Tantunema pakistanense (Timm, 1964) comb. nov. (all measurements in µm).

Characters	n	Females 5	Females 2
n	Females 5	Females 2
L	555.4 ± 33.3 (512 – 606)	466, 546
Body diameter at neck base Body diameter at midbody Body diameter at anus	17.2 ± 0.9 (16 – 19) 18.2 ± 0.9 (17 – 20) 13.2 ± 1.3 (11 – 15)	16, 18 17, 20 12, 15
a	30.5 ± 1.1 (28.4 – 31.6)	27.4, 27.3
b c	3.5 ± 0.2 (3.3 – 3.9) 34.2 ± 1.0 (32.8 – 35.5)	3.5, 4.0 31.0, 32.1
c ’	1.2 ± 0.1 (1.1 – 1.4)	1.2, 1.1
V	51.0 ± 0.9 (49.6 – 52.7)	43.9, 42.8
G2 Lip region diameter Lip region height	14.4 ± 1.4 (12.9 – 17.3) 6.8 ± 0.4 (6 – 7) 2.2 ± 0.4 (2 – 3)	15.4, 12.2 5, 6 3, 3
Amphid aperture	2	2, 2
Odontostyle length	7.6 ± 0.4 (7 – 8)	6, 6
Odontophore length	8.6 ± 0.4 (8-9)	8, 8
Guiding ring from anterior end	4.5 ± 0.4 (4 – 5)	4, 4
Nerve ring from anterior end	62.6 ± 2.8 (57 – 65)	58, 61
Neck length Expanded part of pharynx	155.2 ± 6.9 (143 – 163) 60.4 ± 3.7 (55 – 65)	131, 134 46, 45
Cardia length	4.4 ± 1.0 (3 – 6)	5, 6
Posterior genital branch	80.8 ± 10.1 (73 – 99)	72, 67
Vaginal depth	8 ± 0.6 (7 – 9)	9, 7
Vulva from anterior end	283.6 ± 12.3 (269 – 301)	205, 234
Prerectum length	33.7 ± 3.4 (28 – 37)	30, 32
Rectum length	13.2 ± 2.1 (10 – 16)	7, 15
Tail length	16.2 ± 0.9 (15 – 18)	15, 17