Corresponding author: Jans Morffe (
Academic editor: H-P. Fagerholm
Two new genera and species parasitizing passalid beetles from the Democratic Republic of Congo are described.
The nematode family
One of these genera:
The African fauna of
As a continuation of the studies on Congolese hystrignathids, the present paper deals with two new genera. One of these is created in order to separate two peculiar species of
Several specimens of passalid beetles from the Democratic Republic of Congo were examined during a research visit to the Royal Museum of Central Africa, Tervuren, Belgium. Six specimens of
The hosts were dissected by making incisions in both pleural membranes and the last abdominal sternites. Intestines were extracted and kept in Petri dishes with 70% ethanol. The guts were excised and the parasites removed. Nematodes were transferred to anhydrous glycerine via the slow evaporation method and mounted in the same medium. The edges of the coverslips were sealed using nail polish. Measurements were made with a calibrated eyepiece micrometer attached to a compound microscope. De Man’s ratios a, b, c and V% were calculated. Each variable is shown as the range followed by the mean plus standard deviation in parentheses; the number of measurements is also given. Micrographs were taken with an AxioCam digital camera attached to a Carl Zeiss AxioScop 2 Plus compound microscope. Line drawings were made with the softwares CorelDRAW X3 and Adobe Photoshop CS2 using the micrographs as masters. Scale bars of all plates are given in millimeters.
Some specimens were processed for SEM as follows: they were dehydrated in a graded ethanol series, critical point-dried, mounted in aluminum stubs and coated in gold. SEM micrographs were taken at an acceleration voltage of 22–25 kV.
The type material and vouchers are deposited in the Colección Helmintológica de las Colecciones Zoológicas Collection of the Royal Museum of Central Africa Royal Belgian Institute of Natural Sciences Coleçao Helmintologica do Instituto Oswaldo Cruz
Female. Cervical cuticle armed with wide, scale-like projections, arranged initially in rows of eight elements. Scales divide gradually, forming pointed spines toward the end of the spiny region. Lateral alae present. Head bearing eight rounded, paired papillae. Two short, not prominent cephalic annuli next to head, the second slightly longer and wider than the first. Oesophagus with procorpus clavate, its base set-off from the isthmus. Excretory pore post-bulbar. Genital tract monodelphic-prodelphic. Eggs ovoid. Tail subulate.
Democratic Republic of Congo, Madagascar.
The generic epithet (neuter in gender), is a combination of Batwa, after the pygmy ethnic group that inhabits the D. R. of Congo, and the suffix–nema.
♀ holotype, Democratic Republic of Congo, Ituri province, Mongwalu; in
Vouchers: 3♀♀,Democratic Republic of Congo, Uele region, Bambesa,
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).
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).
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 (
The other genera with scales in the cervical cuticle are
The eggs of both taxa are similar in size (
Gut caeca.
Mongwalu, Ituri province, Democratic Republic of Congo.
Bambesa, Uele region, Democratic Republic of Congo.
Specific epithet in apposition refers to the country of the new taxon.
Female. Cervical cuticle armed with wide, scale-like projections, arranged initially in rows of eight elements. Scales divide gradually, forming spines. Head bearing eight rounded, paired papillae. First cephalic annule cone-like, truncated, comparatively long, moderately inflated. Oesophagus with procorpus sub-cylindrical, its base set-off from the short isthmus. Excretory pore post-bulbar. Genital tract didelphic-amphidelphic. Eggs ovoid. Tail subulate.
Democratic Republic of Congo.
The generic name (neuter in gender) is derived of Chokwe, after an ethnic group from Central Africa (including the D. R. of Congo) and the suffix–nema.
♀ holotype, Democratic Republic of Congo, Ituri province, Mongwalu; in
Vouchers: 3♀♀, Democratic Republic of Congo, Ituri province, Mongwalu; in
Holotype (female) a = 11.65, b = 5.25, c = 13.40, V% = 55.97, total length = 2.680, maximum body width = 0.230, first cephalic annule (length×width) = 0.018×0.063, stoma length = 0.038, procorpus length = 0.400, isthmus length = 0.025, diameter of basal bulb = 0.090, total length of oesophagus = 0.510, nerve ring to anterior end = 0.260, excretory pore to anterior end = 0.720, anus to posterior end = 0.200, eggs = 0.093–0.098×0.038–0.040 (0.095 ± 0.003×0.039 ± 0.001 n = 3).
Paratypes (females) (n = 8) a = 9.09–15.63 (10.87 ± 2.40 n = 6), b = 4.26–4.90 (4.62 ± 0.28 n = 5), c = 11.68–12.53 (12.04 ± 0.36 n = 4), V% = 54.40–57.75 (55.76 ± 1.24 n = 6), total length = 2.000–2.500 (2.192 ± 0.181 n = 6), maximum body width = 0.160–0.225 (0.209 ± 0.021 n = 8), first cephalic annule (length×width) = 0.015–0.020×0.058–0.063 (0.018 ± 0.002×0.060 ± 0.002 n = 6), stoma length = 0.030–0.040 (0.035 ± 0.004 n = 7), procorpus length = 0.330–0.420 (0.376 ± 0.032 n = 7), isthmus length = 0.023–0.038 (0.027 ± 0.006 n = 5), diameter of basal bulb = 0.088–0.100 (0.093 ± 0.005 n = 8), total length of oesophagus = 0.450–0.520 (0.487 ± 0.026 n = 6), nerve ring to anterior end = 0.210–0.260 (0.235 ± 0.021 n = 4), excretory pore to anterior end = 0.660, anus to posterior end = 0.170–0.210 (0.184 ± 0.019 n = 4), eggs = 0.090–0.100×0.038–0.050 (0.097 ± 0.004×0.043 ± 0.004 n = 11).
Female body robust, widening from the base of the first cephalic annule, maximum body diameter at level of the vulva, then tapering towards anus. Cuticle markedly annulated in the spiny region, annuli less marked in the rest of the body (
The other digonant genus with spines in the cuticle and sub-cylindrical procorpus is
gut caeca.
Mongwalu, Ituri province, Democratic Republic of Congo.
Specific epithet derived from the Greek
We thank Dr. Marc de Meyer, curator of the Entomological Collection of the Royal Museum of Central Africa, Tervuren, Belgium for his kind permission to access material deposited in this collection. To Dr. Wilfrida Decraemer, Dr. Yves Samyn, Dr. Marie-Lucie Susini and Dr. Alain Drumont for their assistance during the visit of the senior author to the Royal Belgian Institute of Natural Sciences (RBINS), Brussels. To Julien Cillis (RBINS) for technical help with SEM. To MSc. Yamir Arias, MSc. Eduardo Furrazola and Lic. Susett González (Instituto de Ecología y Sistemática) for their help with the micrographs. To Dr. Pedro Reyes-Castillo (Instituto de Ecología, Veracruz, México) and Dr. Stéphane Boucher (Museum of Natural History, Paris, France) for the identification of the hosts. We are indebted to Dr. Pedro Herrera (Instituto de Ecología y Sistemática) for his review of the English language. The visit to collections in Belgium to access the material and SEM techniques was supported by the Belgian Development Cooperation through the Belgian Focal Point of the Global Taxonomy Initiative (GTI), 2010 and 2012 calls. Open access to this paper was supported by the Encyclopedia of Life (EOL) Open Access Support Project (EOASP).