Batwanema congo, Morffe, Jans & Garcia, Nayla, 2013

Morffe, Jans & Garcia, Nayla, 2013, Batwanema gen. n. and Chokwenema gen. n. (Oxyurida, Hystrignathidae), new nematode genera as parasites of Passalidae (Coleoptera) from the Democratic Republic of Congo, ZooKeys 361, pp. 1-13 : 3-5

Batwanema congo sp. n. Figure 1 A–G, 2 A–E

Type material.

♀ holotype, Democratic Republic of Congo, Ituri province, Mongwalu; in Pentalobus barbatus ; 5.VI.1939; Lepersonne coll.; CZACC 11.4700. Paratypes: 4 ♀♀, same data as holotype, CZACC 11.4701-11.4704; 3 ♀♀, same data as holotype, RMCA; 1 ♀♀, same data as holotype, RIT820; 1 ♀♀, same data as holotype, CHIOC.

Additional material.

Vouchers: 3♀♀,Democratic Republic of Congo, Uele region, Bambesa, 3°28'N, 25°43'E; in Pentalobus sp.; 15.V.1937; J. Vrijdagh coll.; CZACC 11.4705-11.4707. 2♀♀, same data as the latter, RMCA.

Measurements.

Holotype (female) a = 14.81, b = 6.24, c = 7.90, V% = 50.63, total length = 2.370, maximum body width = 0.160, stoma length = 0.045, procorpus length = 0.290, isthmus length = 0.033, diameter of basal bulb = 0.070, total length of oesophagus = 0.380, nerve ring to anterior end = 0.200, excretory pore to anterior end = 0.550, anus to posterior end = 0.300, eggs = 0.100 –0.110×0.045– 0.050 (0.106 ± 0.005 × 0.048 ± 0.003 n = 3).

Paratypes (females) (n = 9) a = 13.20-17.50 (14.72 ± 1.50 n = 9), b = 4.92-5.56 (5.33 ± 0.24 n = 9), c = 6.28-7.48 (6.87 ± 0.40 n = 9), V% = 51.83-54.29 (52.76 ± 0.92 n = 7), total length = 1.820-2.170 (2.013 ± 0.138 n = 9), maximum body width = 0.120-0.160 (0.138 ± 0.015 n = 9), stoma length = 0.040-0.050 (0.045 ± 0.003 n = 9), procorpus length = 0.270-0.320 (0.283 ± 0.016 n = 9), isthmus length = 0.025-0.035 (0.031 ± 0.004 n = 9), diameter of basal bulb = 0.060-0.075 (0.067 ± 0.004 n = 9), total length of oesophagus = 0.350-0.420 (0.378 ± 0.020 n = 9), nerve ring to anterior end = 0.170-0.210 (0.191 ± 0.013 n = 9), excretory pore to anterior end = 0.490-0.550 (0.515 ± 0.026 n = 4), anus to posterior end = 0.260-0.310 (0.293 ± 0.015 n = 9), eggs = 0.098 –0.123×0.030– 0.053 (0.108 ± 0.006 × 0.041 ± 0.006 n = 16).

Specimens from Bambesa.

Females (n = 5) a = 15.91-21.00 (18.40 ± 2.22 n = 5), b = 5.11-6.10 (5.60 ± 0.40 n = 5), c = 5.39-6.13 (5.68 ± 0.30 n = 5), V% = 49.74-54.30 (51.84 ± 1.65 n = 5), total length = 1.510-1.890 (1.716 ± 0.162 n = 5), maximum body width = 0.080-0.110 (0.094 ± 0.011 n = 5), stoma length = 0.040-0.050 (0.043 ± 0.004 n = 5), procorpus length = 0.185-0.270 (0.227 ± 0.030 n = 5), isthmus length = 0.025-0.038 (0.032 ± 0.005 n = 5), diameter of basal bulb = 0.033-0.058 (0.049 ± 0.010 n = 5), total length of oesophagus = 0.258-0.360 (0.308 ± 0.036 n = 5), nerve ring to anterior end = 0.135-0.180 (0.155 ± 0.019 n = 4), excretory pore to anterior end = 0.380-0.430 (0.397 ± 0.029 n = 3), anus to posterior end = 0.280-0.340 (0.302 ± 0.023 n = 5), eggs = 0.095 –0.118×0.033– 0.045 (0.110 ± 0.008 × 0.039 ± 0.005 n = 10).

Description.

Body comparatively slender, widening from the base of the second cephalic annule, maximum body diameter at level of the vulva, tapering towards anus. Cuticle markedly annulated in the spiny region, annuli (ca. 2 µm) less marked in the rest of body. Cervical region armed with rows of cuticular projections from the end of the second cephalic annule to the base of isthmus. First row consisting of eight wide, rectangular, scale-like cuticular projections. At level of row 3-4, a shallow cleavage at midpoint of the scales becoming deeper and wider towards the posterior region of body, until reaching row 8-9, where each scale is divided in two or three spines, their tips rounded. Next to it, spines become pointed gradually and increase their number: ca. 22 elements in the median rows and ca. 34 in the last rows. Lateral alae commencing at level of the isthmus, within the spiny region and extending to about three body-widths posterior to the vulva. Sub-cuticular longitudinal striae present. Head set-off from body by a deep groove, bearing eight rounded, less prominent, paired papillae. Amphids lateral, pore-like. Next to head, two short, not prominent cephalic annule; the second slightly wider and longer than the first. Cephalic annuli poorly differentiated one from the other, only by a shallow groove. Mouth circular. Stoma about four head-lengths long, surrounded by an oesophageal collar. Lumen of anterior region of stoma triangular, with a ridge in each side. Oesophagus consisting of a muscular clavate procorpus, well set-off from the isthmus. Basal bulb rounded, valve plate well developed. Intestine simple, sub-rectilinear. Rectum short, anus not prominent. Nerve ring encircling procorpus at about its midpoint. Excretory pore situated at about half of body width posterior to basal bulb. Vulva a median transverse slit near midbody, lips slightly prominent. Vagina muscular, forwardly directed. Genital tract monodelphic-prodelphic. Ovary reflexed behind the excretory pore, distal flexure ca. 1.5 body-widths long. Eggs ovoid, shell with eight rough, longitudinal, hardly prominent ridges. Tail conical, subulate, ending in a sharp point. Male unknown.

Discussion.

Batwanema gen. n. presents a similar arrangement of the cervical cuticular projections to Chokwenema gen. n., consisting of a first row of eight rectangular scales that gradually bifurcate, becoming pointed spines. It can be differentiated by its reproductive system monodelphic-prodelphic contrary to didelphic-amphidelphic. The genus has two cephalic annuli barely expanded vs. the unique truncate, more expanded first cephalic annule of Chokwenema gen. n. In addition, the procorpus of Batwanema gen. n. is clavate vs. sub-cylindrical.

The other genera with scales in the cervical cuticle are Lepidonema Cobb, 1898 and Salesia Travassos & Kloss, 1958, both having genital tracts didelphic-amphidelphic and with more elements in the first row of spines: 16 vs. 8 and a single, large cephalic annuli vs. the two shorter of Batwanema gen. n. Also, Lepidonema has a sub-cylindrical procorpus vs. the clavate of Batwanema gen. n.

Van Waerebeke (1973) described 14 species of Malagasian Artigasia , all of these quite variable in the shape of the cephalic end and the form and arrangement of spines. Two of such species: Artigasia lata and Artigasia annulata are characterized, in addition to the clavate procorpus and the monogonant genital tract, by the presence of two cephalic annuli (the second larger) and the cervical region with scale-like cuticular projections. These scales are arranged initially in a row of eight elements, which increase their number and become gradually in pointed spines. The latter features agree with the diagnosis of Batwanema gen. n., supporting the establishment of Batwanema latum comb. n. and Batwanema annulatum comb. n. as new combinations of Artigasia lata and Artigasia annulata .

Batwanema congo gen. n. et sp. n. can be segregated from Batwanema latum comb. n. by the extension of the cervical spines and lateral alae. In the new species, the spines end at level of the basal bulb vs. the level of the nerve ring in Batwanema latum comb. n. On the other hand, the lateral alae of Batwanema congo gen. n. et sp. n. arise within the spiny region and extend to a distance beyond the vulva, whereas Batwanema latum comb. n. presents lateral alae from the beginning of the isthmus to the level of anus. Batwanema congo gen. n. et sp. n. has a larger body (1.820-2.370 vs. 1.360-1.472) but the oesophagus is comparatively shorter (b = 4.92-6.24 vs. 4.10-4.60).

The eggs of both taxa are similar in size ( Batwanema congo gen. n. et sp. n. = 0.098 –0.123×0.030– 0.053; Batwanema latum = 0.112 –0.116×0.039– 0.042), but are ridged-shelled in Batwanema congo gen. n. et sp. n. vs. the smooth-shelled eggs of Batwanema latum comb. n. The tail of Batwanema congo gen. n. et sp. n. is comparatively longer (c = 6.28-7.90 vs. 11.00-13.00).

Batwanema congo gen. n. et sp. n. differs from Batwanema annulatum comb. n. by the cervical spines extending further down the body, whereas Batwanema annulatum comb. n. has spines ending before the level of the basal bulb. Lateral alae of Batwanema annulatum comb. n. extend from the level of the isthmus to the level of the anus in opposition to Batwanema congo gen. n. et sp. n. where the lateral alae clearly finish before the anus. Batwanema congo gen. n. et sp. n. is also longer (1.820-2.370 vs. 1.439-1.509), with the oesophagus comparatively shorter (b = 4.92-6.24 vs. 4.50-4.60). Moreover, the eggs of Batwanema annulatum comb. n. are smooth-shelled vs. the ridged-shelled ones of Batwanema congo gen. n. et sp. n.

Type host.

Pentalobus barbatus (Fabricius, 1801) ( Coleoptera : Passalidae ).

Other host.

Pentalobus sp. ( Coleoptera : Passalidae ).

Site.

Gut caeca.

Type locality.

Mongwalu, Ituri province, Democratic Republic of Congo.

Other locality.

Bambesa, Uele region, Democratic Republic of Congo.

Etymology.

Specific epithet in apposition refers to the country of the new taxon.