Kongonema meyeri, Morffe, Jans & Garcia, Nayla, 2013

Morffe, Jans & Garcia, Nayla, 2013, Two new genera of nematode (Oxyurida, Hystrignathidae) parasites of Passalidae (Coleoptera) from the Democratic Republic of Congo, ZooKeys 257, pp. 1-15 : 2-4

Kongonema meyeri sp. n. Figs 1 A–G, 2 A–D, 3 A–E

Type material.

♀ holotype, Democratic Republic of Congo, Kivu Region, Katale, 1°19'S, 29°22'E; in Didimus sp.; 4.V.1939; Hautmann coll.; CZACC 11.4653. Paratypes: 10♀♀, same data as holotype, CZACC 11.4654-11.4663; 10♀♀, same data as holotype, RMCA; 4♀♀, same data as holotype, CHIOC; ♂, same data as holotype, CZACC 11.4664; ♂, same data as holotype, RMCA.

Additional material.

Vouchers: 2♀♀, Democratic Republic of Congo, Kivu Region, Katale, 1°19'S, 29°22'E; in Didimus sp.; 4.V.1939; Hautmann coll., RBINS. 2♀♀, Democratic Republic of Congo, Kivu Region, Katale, 1°19'S, 29°22'E; in Erionomus pilosus ; 4.V.1939; Hautmann coll.;CZACC 11.4665-11.4666; 2♀♀, same data as the latter, RMCA;

Measurements.

Holotype (female) a = 12.15, b = 5.06, c = 7.26, V% = 58.08, total length = 1.670, maximum body width = 0.138, first cephalic annule ( length×width) = 0.013 × 0.038, stoma length = 0.050, procorpus length = 0.260, isthmus length = 0.020, diameter of basal bulb = 0.058, total length of oesophagus = 0.330, nerve ring to anterior end = 0.185, excretory pore to anterior end = 0.440, vulva to posterior end = 0.700, anus to posterior end = 0.230, eggs = 0.123 × 0.050 (n = 1).

Paratypes (females) (n = 24) a = 8.65-13.08 (10.68 ± 0.90 n = 23), b = 4.30-5.03 (4.71 ± 0.71 n = 21), c = 5.65-7.45 (6.43 ± 0.37 n = 23), V% = 53.02-58.82 (55.91 ± 1.43 n = 23), total length = 1.400-1.670 (1.530 ± 0.075 n = 23), maximum body width = 0.120-0.170 (0.144 ± 0.012 n = 24), first cephalic annule ( length×width) = 0.013-0.025 × 0.038-0.043 (0.016 ± 0.003 × 0.041 ± 0.002 n = 19), stoma length = 0.033-0.050 (0.045 ± 0.005 n = 19), procorpus length = 0.210-0.270 (0.244 ± 0.013 n = 20), isthmus length = 0.020-0.033 (0.024 ± 0.003 n = 22), diameter of basal bulb = 0.053-0.070 (0.061 ± 0.004 n = 24), total length of oesophagus = 0.283-0.350 (0.324 ± 0.014 n = 21), nerve ring to anterior end = 0.148-0.190 (0.172 ± 0.011 n = 21), excretory pore to anterior end = 0.320-0.490 (0.402 ± 0.046 n = 23), vulva to posterior end = 0.620-0.750 (0.674 ± 0.038 n = 23), anus to posterior end = 0.200-0.280 (0.239 ± 0.019 n = 23), eggs = 0.120-0.133 × 0.043-0.063 (0.125 ± 0.004 × 0.051 ± 0.006 n = 26).

Paratypes (males) (n = 2) a = 15.67-17.33 (16.50 ± 1.18 n = 2), b = 3.47-3.58 (3.52 ± 0.08 n = 2), c = 121.33-125.33 (123.33 ± 2.83 n = 2), total length = 0.910-0.940 (0.925 ± 0.021 n = 2), maximum body width = 0.053-0.060 (0.056 ± 0.005 n = 2), procorpus length = 0.250 (n = 2), isthmus length = 0.018-0.020 (0.019 ± 0.002 n = 2), diameter of basal bulb = 0.035 (n = 2), total length of oesophagus = 0.263 (n = 2), nerve ring to anterior end = 0.138-0.148 (0.143 ± 0.007 n = 2), excretory pore to anterior end = 0.290-0.330 (0.310 ± 0.028 n = 2), cloacae to posterior end = 0.008 (n = 2).

Specimens from Erionomus pilosus .

Females (n = 4) a = 9.46-10.75 (10.06 ± 0.68 n = 4), b = 4.75-4.97 (4.87 ± 0.09 n = 4), c = 6.58-7.13 (6.82 ± 0.23 n = 4), V% = 55.56-61.59 (57.75 ± 2.72 n = 4), total length = 1.640-1.750 (1.703 ± 0.046 n = 4), maximum body width = 0.153-0.185 (0.170 ± 0.015 n = 4), first cephalic annule ( length×width) = 0.018-0.020 × 0.043-0.048 (0.019 ± 0.001 × 0.045 ± 0.002 n = 4), stoma length = 0.048-0.053 (0.050 ± 0.003 n = 4), procorpus length = 0.255-0.275 (0.267 ± 0.009 n = 4), isthmus length = 0.020-0.025 (0.023 ± 0.002 n = 4), diameter of basal bulb = 0.068-0.075 (0.071 ± 0.004 n = 4), total length of oesophagus = 0.330-0.360 (0.350 ± 0.014 n = 4), nerve ring to anterior end = 0.185-0.195 (0.189 ± 0.004 n = 4), excretory pore to anterior end = 0.420-0.510 (0.475 ± 0.040 n = 4), vulva to posterior end = 0.630-0.760 (0.720 ± 0.61 n = 4), anus to posterior end = 0.230-0.260 (0.250 ± 0.014 n = 4), eggs = 0.120-0.130 × 0.048-0.065 (0.126 ± 0.004 × 0.058 ± 0.007 n = 7).

Description.

Female.Body comparatively robust, widening from the base of the first cephalic annule, maximum body diameter at level of the vulva, then tapering towards anus. Cervical cuticle unarmed, markedly annulated (annuli ca. 5-7 µm). Rest of the body with marked annuli decreasing their width towards the level of the anus. Sub-cuticular longitudinal striae present. Lateral alae ca. 9 µm wide, from the oesophageal region (ca. 30 µm before the level of the nerve ring) to a very short distance beyond the level of the anus. Posterior ends of the lateral alae rounded, forming short lobes. Head well developed, set-off from body by a single, deep groove and bearing eight rounded, paired papillae. Amphids pore-like, laterally situated. Mouth sub-triangular in shape. First cephalic annule cone-like, truncate, barely inflated, about two head-lengths long. Stoma comparatively long, about three first cephalic annule lengths long, surrounded by an oesophageal collar. Oesophagus consisting of a muscular, sub-cylindrical procorpus, its base slightly wider and well set-off from the short isthmus. Basal bulb sub-spherical, valve plate well developed. Intestine simple, sub-rectilinear, anterior portion dilated. Rectum short, anus not prominent, as a crescent-like slit. Nerve ring encircling procorpus at about its midpoint. Excretory pore situated at about half of a body width posterior to basal bulb. Genital tract didelphic-amphidelphic, both ovaries reflexed. Anterior ovary reflexed behind the excretory pore, posterior ovary reflexed at about a body width before the anus. Distal flexures of ovaries about one body width-length long. Oöcytes in single rows. Vulva a median transverse slit slightly displaced to the posterior half of body, lips prominent. Vagina muscular, forwardly directed. Eggs ovoid, bearing eight longitudinal, rough, ridges on the shell. Tail comparatively long, filiform, subulate, ending in a sharp point.

Male.

Body shorter than female, comparatively slender, posterior region ventrally curved. Cervical cuticle unarmed. Sub-cuticular longitudinal striae present. Lateral alae from the oesophageal region (about three body-widths posterior to the cephalic end) to the level of the single mammiform papilla (about a body-width before the level of anus). Head not set-off from body. First cephalic annule not developed. Stoma not defined. Oesophagus consisting of a sub-cylindrical procorpus, well set-off from the short isthmus. Basal bulb rounded, valve plate well developed. Intestine simple, anterior portion slightly dilated. Nerve ring encircling procorpus at its posterior half, about 65% of its length. Excretory pore situated at about 1.5 body-widths posterior to basal bulb. Monorchic. Testis outstretched, arising at a short distance behind the excretory pore. Spicule absent. Dorsal cuticle of the tail region thickened. A single, large, pre-cloacal ventromedian mammiform papilla situated at about a body width before the posterior end. A pair of small, pre-cloacal, sub-lateral papillae situated at a short distance before the level of the cloaca. Tail region becoming sharp visibly from the beginning of the cuticular thickening, until forming a very short tail appendage, its tip rounded.

Discussion.

There are three genera of hystrignathids the female of which present the cervical cuticle unarmed, procorpus sub-cylindrical and reproductive system digonant: Anomalostoma Cordeira, 1981; Coynema (Coy, García & Alvarez, 1993) Morffe & García, 2011 and Ventelia Travassos & Kloss, 1958. The first differs by having the anterior region of the procorpus strongly swollen, surrounding the stoma ( Cordeira 1981). The stoma of Kongonema gen. n. is surrounded only by an oesophageal collar, as occur in many hystrignathids. Anomalostoma lacks an evident first cephalic annule vs. conspicuous first cephalic annule of Kongonema gen. n.

Females of Coynema can be segregated by the basal dilatation of its procorpus and the anterior region of the intestine notably inflated, forming a saccular structure ( Morffe and García 2011). Both traits are absent in Kongonema gen. n., which procorpus increases its diameter slightly and gradually towards its base and the fore region of the intestine is only moderately inflated, without the saccular structure mentioned above. The oviduct next to the vagina forms a loop in Coynema , instead of the straight oviduct of the present genus.

The males of Kongonema gen. n. resemble their counterparts of Coynema (only close genus where the male is known) by lacking of spicule and by having a similar arrangement of the copulatory papillae: the ventromedian pre-cloacal papilla (typical of Hystrignathidae ) and another pair of small sub-lateral pre-cloacal papillae. Kongonema gen. n. differs by having a sub-cylindrical procorpus, without the basal dilation and by lacking the saccular region of the intestine characteristic of Coynema . The posterior end of Kongonema gen. n. forms a short, rounded tail appendage vs. the sharp tail of Coynema .

On the other hand, Ventelia has the procorpus barely set-off from the isthmus, since the posterior third of the procorpus decreases its diameter. The hind procorpus of Kongonema gen. n. increases its diameter slightly and is well differentiated from the isthmus.

Type host.

Didimus sp. ( Coleoptera : Passalidae ).

Other host.

Erionomus pilosus Aurivillus, 1896 ( Coleoptera : Passalidae ).

Site.

Gut caeca.

Type locality.

Katale, Kivu region, Democratic Republic of Congo.

Etymology.

Specific epithet dedicated to Dr. Marc de Meyer, curator of the Entomological Collection of the Royal Museum of Central Africa, Tervuren, Belgium. In appreciation of his kind help by permitting access to the material assessed.