Axonchium phukani Rahman, Jairajpuri & Ahmad, 1985

Naz, Tabbasam & Ahmad, Wasim, 2012, Description of two new and five known species of the genus Axonchium Cobb, 1920 (Nematoda: Dorylamida) from India with diagnostic compendia and keys to species of the genera Axonchium and Syncheilaxonchium Coomans & Nair, 1975, Zootaxa 3264, pp. 1-37 : 16-19

Axonchium phukani Rahman, Jairajpuri & Ahmad, 1985

( Figs. 7–8 )

Measurements. Table 4 .

Description. Female: Cuticle 2–3 µm thick at mid body and 6–9 µm on tail. Lateral chords about one-fourth of body width at mid body.

Lip region offset by constriction, about one-sixth of body width at neck base; lips separate. Amphids cupshaped, their aperture about two-thirds or 0.8 times lip region width. Odontostyle 1.0–1.2 times lip region width long. Odontophore 1.1–1.3 times the odontostyle length. Anterior part of pharynx muscular, separated from the posterior expanded part by a deep constriction, the latter occupying about 60–70% of total neck length. Cardia conoid, about one-third of the corresponding body width long.

Anterior genital branch represented by a simple uterine sac, 80–150 µm long, filled with sperms and provided with a proximal constriction. Posterior branch well developed; ovary reflexed, not reaching the oviductuterus junction, measuring 50–112 µm; oviduct measuring 80–115 µm, consisting of a long slender part with prismatic cells and a slightly wider pars dilatata filled with sperms; well developed sphincter present at oviduct-uterus junction. Uterus filled with sperms, measuring 60–110 µm, tripartite, having a distal dilated bulb-like part with wide lumen, intermediate narrow convoluted part with narrow lumen and a proximal wide tubular part. Vagina straight, extending inwards about half of the corresponding body width; pars proximalis vaginae 15–23 µm long; pars refringens vaginae absent; pars distalis vaginae 4–5 µm with slightly concave walls. Prerectum 4.2–6.4 times anal body width long. Rectum about one anal body width long. Tail broadly rounded, 0.8–0.9 times anal body width long. Caudal pores two on each side.

Male: Spicules dorylaimoid, ventrally curved with bluntly rounded distal ends, 1.3–1.5 times the cloacal body width long, inner walls heavily sclerotized. Lateral guiding pieces slender, rod-like with bifid distal ends, about one-fourth of the spicule length. Supplements consisting of an adcloacal pair and four to five spaced ventromedians, starting anterior to the range of spicules. Prerectum 5.5–6.5 times cloacal body width long. Rectum about as long as cloacal body width. Tail broadly rounded, 0.8–0.9 times cloacal body width. Caudal pores two on each side.

Characters Females Males Paratype female Paratype male Habitat and locality. From soil around the roots of forest trees (unidentified), from Kaziranga National Park, Assam, India. GPS coordinate 26.64071/93.39958; latitude 26o36’N, longitude 93o28’E

Remarks. Rahman et al. (1985) described this species from Meghalaya and Assam in India and Jongkar in Bhutan. The present population from Assam conforms well to the original description. A paratype female and a male of this species available in the collection of the Department of Zoology, Aligarh Muslim University were also examined and were found to fit well with the present population, except that the present specimens are slightly more robust (a = 32.8–40.6 vs 42). This species is closely related to A. heynsi Nair, 1973 and A. thoubalicum Dhanachand & Jairajpuri, 1981 . From the former it differs in having a shorter prerectum (5.5–6.5 anal body widths vs 10–15 anal body widths long), longer tail (c = 48–58 vs c = 73–108) and in spicule shape (vs stout with a blunt posterior projection at the distal end, sometimes inner walls irregularly crenate). From A. thoubalicum , it differs in the nature of anterior uterine sac (presence vs absence of proximal constriction), in the absence of characteristic swollen portion near the distal end of the middle piece of spicules and in the shape of lateral guiding pieces (vs simple rod-like).

Figures

FIGURE 7. Axonchium phukani Rahman, Jairajpuri & Ahmad, 1985. A: Entire female. B: Entire male. C: Anterior region. D: Anterior end showing amphid. E – F. Junction between two parts of pharynx. G – H: Pharyngo-intestinal junction. I: Female genital system. J: Vulval region showing anterior uterine sac. K: Female posterior end. L: Male posterior region. M: Spicule. N: Lateral guiding piece.

FIGURE 8. Axonchium phukani Rahman, Jairajpuri & Ahmad, 1985. A: Anterior region. B: Anterior end showing amphid. C: Junction between two parts of pharynx. D: Pharyngo-instestinal junction. E: Vulval region. F: Female posterior end. G: Ventromedian supplements. H – I: Male posterior end. (Scale bars: A, B = 10 µm; C – I = 20 µm).

Tables

TABLE 4. Morphometrics of Axonchium phukani Rahman, Jairajpuri and Ahmad, 1985 (All measurements in µm (except L) and in the form: mean ± standard deviation (range).

n: 6	3	1	1
L (mm) 1.47±0.08 (1.4-1.6)	1.5±0.1(1.4-1.6)	1.6	1.6
a 35±3.22 (32.8-40.6)	37.7±2.7 (34.7-39.9)	42	46.4
b 2.6±0.24 (2.2-2.8)	2.9±0.45 (2.5-3.4)	2.8	3.4
c 54.5±4.22 (48.1-58.1)	50.5±2.8 (47.5-53.2)	48	50.7
c`0.86±0.05 (0.8-0.9)	1.02±0.01 (1-1.03)	1.0	1.06
V 53.9±1.01 (52.9-54.9)	-	53.5	-
G1 8.6±1.38 (7.01-10.4)	-	10.4	-
G2 14.9±3.01 (12.5-20.7)	-	16.07	-
Lip region width 7.5±0.5 (7-8)	7.3±0.57 (7-8)	8	8
Lip region height 3.67±0.52 (3-4)	4	4	4
Amphid aperture 6.34±0.51 (6-7)	5		7
Odontostyle length 9±0.63 (8-10)	9.3±0.57 (9-10)	10	10
Odontophore length 11±0.89 (10-12)	11±1 (10-12)	12	12
Guiding ring from anterior end 7.8±0.75 (7-9)	8.3±0.57 (8-9)	8	8
Nerve ring from anterior end 118±2.47 (115-120)	127±11.5 (120-140)	140	-
Neck length 576±51.1 (510-662)	576±53.6 (465-570)	625	470
Expanded part of pharynx 370±57.06 (295-465)	318±65.2 (250-380)	440	265
Cardia length 14±2.23 (11-17)	13.7±4.7 (10-19)		14
Body width at mid body 42.8±2.1 (40-45)	41±1 (40-42)	40	35
Body width at neck base 43.5±2.16 (41-47)	42±1.5 (41-44)	35	32
Body width at anus/cloaca 30.5±1.37 (28-32)	30±1 (29-31)	35	30
Anterior genital branch 106±23.9 (80-150)	-	175	-
Posterior genital branch 223±37.06 (190-315)	-	270	-
Vaginal depth 22.5±3.2 (17-25)	-	-	-
Vulva from anterior end 810±29.9 (771-862)	-	900	-
Prerectum length 153±26.6 (120-200)	170±10 (160-180)	205	-
Rectum length 32.2±3.34 (27-35)	-	40	40
Tail length 27.6±2.06 (25-30)	30.7±1.15 (30-32)	35	32
Spicules length -	41±6.14 (40-47)	-	40
Lateral guiding pieces -	11.6±0.47 (11-12)	-	11
Ventromedian supplements -	4	-	4