Research Article |
Corresponding author: Nestor Fernandez ( nestorfernand51@yahoo.fr ) Academic editor: Vladimir Pesic
© 2016 Nestor Fernandez, Pieter Theron, Sergio Leiva.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Fernandez N, Theron P, Leiva S (2016) Revision of the family Carabodidae (Acari, Oribatida) V. Fourth part. Two new species of the genus Congocepheus from the Republic of Rwanda: Congocepheus rwandensis sp. n., and Congocepheus kayoveae sp. n. ZooKeys 556: 19-41. https://doi.org/10.3897/zookeys.556.7011
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Two new species from Rwanda are described utilizing optical and scanning electron microscope observations: Congocepheus rwandensis sp. n. and Congocepheus kayoveae sp. n. are compared to Congocepheus taurus
Congocepheus rwandensis sp. n., Congocepheus kayoveae sp. n., Rwanda, comparison
Several species of the genus Congocepheus have recently been redescribed, namely Co. heterotrichus Balogh, 1958, Co. orientalis Mahunka, 1987, Co. hauseri Mahunka, 1989 (
Cavaecarabodes includes some species previously considered members of the genus Congocepheus. Type specimens of Co. ornatus Mahunka, 1983, Co. latilamellatus Mahunka, 1984 and Co. velatus Mahunka, 1986 were studied to establish their position in Congocepheus, and at the same time large collections of material were obtained from Rwanda, Zimbabwe, Kenya, Cameroon, the Republic of the Congo, Côte d’Ivoire and Thailand, which are housed at the
In this paper, two new species from Rwanda are described, making use of optical microscopy and SEM. Valuable information was obtained from SEM studies, which would be extremely difficult to obtain with optical microscopy alone.
Specimens studied by means of light microscopy were macerated in lactic acid and observed in the same medium using the open-mount technique (cavity slide and cover slip) as described by
Specimens were also studied by means of scanning electron microscope (SEM). Specimens preserved in ethanol were carefully rinsed by sucking them several times into a Pasteur pipette, after which they were transferred to buffered glutaraldehyde (2.5%) in Sörensen phosphate buffer: pH 7.4; 0.1 m for two hours. After postfixation for 2 hours in buffered 2% OsO4 solution and being rinsed in buffer solution; all specimens were dehydrated in a series of graded ethanol and dried in a critical point apparatus. After mounting on Aluminium-stubs with double sided sticky tape, specimens were gold coated in a sputter apparatus (
Leg chaetotaxy studies using standard, polarized and phase contrast microscopes are provisional, due to the fact that only adult specimens were available. Setal formulae of the legs include the number of solenidia (in parentheses); tarsal setal formulae include the famulus (ε).
Morphological terms and abbreviations used are those developed by F. Grandjean (1928–1974) (cf.
The specific epithet is derived from Rwanda, country of origin of the type material.
Holotype: Female. “73/2. Kayove-Rwanda; 2100 mts.15/V/1973” Leg. P.Werner; material deposited in the Collection of the Natural History Museum of Geneva (
Paratype: two adult females, same locality and date as Holotype; deposited in Collection of
Integumental microsculpture: prodorsal, notogastral and ventral zones smooth to slightly irregularly tuberculate; notogaster with irregular cord-shaped structures and short, fingerlike projection. Setation: with medial dentate vein: rostral setae small; interlamellar setae large, directing backward; lamellar: wide, short with central dentate vein; notogastral, epimeral, genital, aggenital, anal and adanal setae: simple. Prodorsum: wide elevated interlamellar process; in setae anteriorly on elevated zone; sensillus: cylindrical, short barbs. Bothridial ring, bothridial tooth present, smooth. Large posterior prodorsal depression. Notogaster: small notogastral anterior depression; fourteen pairs of setae. Lateral zone: tutorium: large lamina, small relative to pedotectum I. Ventral region: epimera slightly elevated; 3-4 fused; epimeral chaetotaxy 3-1-3-3; discidum clearly discernible; anterior genital furrow clearly visible; four pairs of genital setae in a unique line; aggenital setae inserted posterior to genital opening. Three pairs of adanal seta; ad3 near aggenital setae; anal plate polyhedral, sharply tipped; two pairs of anal setae; lyrifissures iad between ad3 and ad2; conspicuous depressions situated laterally to genital and anal openings.
Measurements. SEM: 475 μm (473–477) × 225 μm (223–227) (measurements on three specimens). Light microscopy: 476 μm (473–478) × 227 μm (228–227) (measurements on three specimens).
Shape.
Elongate oval (Figures
Colour. Specimens without cerotegument, light brown to yellowish-brown when observed in reflected light.
Cerotegument.
Present on: prodorsum, notogaster, ventral region. Consistently granulated to amorphous layer covering body (1.5–3.0 μm), with adhering soil particles, impeding observation of cuticular ornamentations; on legs thin layer (less than 1 μm) (Figures
Absent on: lamellar lateral border (Lam), bothridial ring (bo.ri), humeral apophysis (h.ap) and bothridium (bo) (Figures
Sometimes absent: ventral depression (dep) behind leg IV and notogastral zone between s.c and notogastral edge (Figure
Integument.
Microsculpture: smooth to slightly irregular tuberculate (Figures
On central notogastral zone, network of irregular cord-shaped structures (c.s.s) (indicated byX, Figure
Setation.
SEM-observations were necessary in order to determine setal shapes. Notogastral and prodorsal setae (ro, in) (Figures
Wide, short le setae (Figure
Prodorsum.
Polyhedral (dorsal view) (Figure
Sensillus (si) cylindrical with short barbs (Figure
Notogaster.
Shape: in dorsal view anterior rectangular, in posterior view oval (Figure
Fourteen pairs of setae: c1, c2, da, dm, dp, la, lm, lp, h1, h2, h3, p1, p2, p3; c1 setae directing forward (Figures
Lateral region (Figure
Deep supra tutorial depression (s.tu.d) running between and parallel to lamellae and tutorium; large pocket depression (a.tu.d) anteriorly. Pedotectum I, large extended lamina, covering acetabulum I, rounded apex. Pedotectum II, small ovoid lamina; discidium (dis) well discernible, small, triangular, rounded apex.
Bothridia cup-shaped; bothridial opening directing downward (Figures
Ventral region (Figure
Epimeral chaetotaxy 3-1-3-3. Discidum easily discernible; anterior genital furrow (a.g.f) clearly visible, situated in front of genital plate. Large genital plate; four pairs of genital setae, simple linear arrangement; all setae more or less equal in length; aggenital setae (ag) situated posteriorly to genital opening. Three pairs of adanal seta; ad3 close to ag setae. Anal plate polyhedral, sharply tipped. Two pairs of anal setae. Lyrifissures iad well discernible, situated laterally between ad3 and ad2. Depressions (dep) clearly visible, situated laterally to genital and anal openings.
Legs (Figures
Leg I | Femur | Genu | Tibia | Tarsus | Claw |
---|---|---|---|---|---|
setae | d,l”,v | l”,v | v,l’,d | (ft),ε,(tc),(it),(p), (u),(a),s,(pv) | 1 |
solenidia | σ | φ1, φ2 | ω 1, ω 2 | ||
Leg II | |||||
setae | dp,da,l,v | d,l’,v | v,d,l” | (pv),s,(a),(u),(p), (it),(tc),(ft) | 1 |
solenidia | σ | φ | ω 1, ω 2 | ||
Leg III | |||||
setae | d,l’,v | l’’ | l”,v | (pv),s,(a),(u),(p), (it),(tc),ft’’ | 1 |
solenidia | σ | φ | - | ||
Leg IV | |||||
setae | d,v | d,l’’ | l”(v) | (pv),s,(a),(u),(p), (tc),(ft) | 1 |
solenidia | - | φ | - |
The cerotegumental layer impedes clear observation of c.s.s and f.l.p. Observation of notogastral setae was complicated due their length and the fact that they are twisted. Residues adhering to setal surfaces further hampered clear observation.
The specific epithet is derived from Kayove, Rwanda, where the type material was collected.
Holotype Female. “73/2. Kayove- Rwanda; 2100 mts. 15/V/1973” Leg. P.Werner; material deposited in the Collection of the Natural History Museum of Geneva (
Integumental microsculpture: notogaster with irregular cord-shaped structures and elongate fingerlike projection.
Setation: simple: epimeral, genital, aggenital, anal, adanal, subcapitular; one central dentate vein, margin dentate: notogastral; two dentate veins, margin dentate: rostral, interlamellar; flat setae, margin dentate, central dentate vein: lamellar.
Prodorsum: elevated interlamellar process complete; margin of laterodorsal lamellae slightly elevated. Prominent triangular lamellar tip, lamellar setae situated externally; shallow lamellar furrow terminating near internal limit of lamellar tip. Tutorium spoon-shaped, larger than Pedotectum I. Rostrum: rounded undulate margin, wide, large, projecting forward. Epimera elevated, delimited by deep furrow; deep hollow paraxially to epimere 1; epimeres 3 and 4 unfused. Epimeral chaetotaxy 3-1-3-3. Genital plate rounded; four or five pairs of genital setae; aggenital setae posterior to genital opening, far from ad3.
Measurements. SEM: 464 μm (462–467) × 173 μm (172–180) (measurements on six specimens). Light microscopy: 467 μm (465–468) × 175 μm (173–183) (measurements on five specimens).
Shape.
Elongate oval (Figure
Congocepheus kayoveae sp. n. Adult female, SEM. 19 dorsal view, with detail of fingerlike projection (f.l.p) 20 lateral view, bothridium, sensillus and humeral apophysis 21 rostral setae 22 cuticular microsculpture 23 cerotegumental layer and cuticular microsculpture 24 interlamellar setae. Abbreviations: see “Material and methods”. Scale bars: (19) 100 μm (detail of f.l.p = 20 μm); (20) 20 μm; (21, 23, 24) 10 μm; (22) 5 μm.
Cerotegument.
Present: thin amorphous layer (0,3–0,5 μm) on prodorsum, notogaster, ventral region; with adhering soil particles principally on e.i.p and central notogastral zone (Figures
Integument.
Pusticulate (Figure
Congocepheus kayoveae sp. n. Adult female SEM. 34 subcapitulum, ventral view 35 prodorsum, frontal view 36 lamellar setae (le), lateral view 37 setae dp, dorsal view 38 seta d femur III, lateral view. Abbreviations: see “Material and methods”. Scale bars: (33) 20 μm; (34) 50 μm; (35–37) 10 μm.
Setation.
Simple: epimeral (Figures
Prodorsum.
Polyhedral (dorsal view) (Figure
Sensillus (si) (Figure
Rostral margin slightly rounded, margin undulate (Figure
Lamellae running dorsolaterally (Figures
Notogaster.
Ovoid in dorsal view, with slight constriction at level of da, la setae (Figure
Fourteen pairs of setae: c1, c2, da, dm, dp, la, lm, lp, h1, h2, h3, p1, p2, p3; c1 (86 ± 5 μm); c2 (75 ± 5 μm) both setae long and thin, direction variable but in most cases directing forward (Figure
Cord-shaped structures (c.s.s) converging in central anterior zone forming an elongate fingerlike projection (f.l.p) (53 ± 5 μm (Figure
Lateral region (Figures
Tutorium (tu) prominent lamina, curving margin, clearly discernible, smooth cuticula (Figures
Bothridial ring (bo.ri) smooth, with bo.to, hardly discernible due to positioning of lateral antiaxial setae (l”) of genu II (Figure
Clearly delimited zone on s.c with more or less smooth cuticula, immediately followed by clearly delimited pusticulate zone (Figure
Frontal view (Figures
Complete, flat e.i.p (Figure
Ventral region (Figures
Legs (Figures
Leg I | Femur | Genu | Tibia | Tarsus | Claw |
---|---|---|---|---|---|
setae | da, dp, v, l” | d,v | (v), l”,d | (ft),ε,(tc),(it),(p),(u),(a), s,(pv), Ad” | 1 |
solenidia | σ | φ1, φ2 | ω 1 , ω 2 | ||
Leg II | |||||
setae | dp, da, l’ | d,l’,v | v, d, l’ | (pv), s,(a),(u),(p), (it), (tc), (ft) | 1 |
solenidia | σ | φ | ω 1, ω 2 | ||
Leg III | |||||
setae | d, l’,v | l’ | (v) | (pv),s,(a),(u),(p),(it),(tc), ft’’ | 1 |
solenidia | σ | φ | - | ||
Leg IV | |||||
setae | d , v | d, l’ | l’, (v) | (pv), s,(a),(u), (p), (tc), ft” | 1 |
solenidia | - | φ | - |
In some specimens the cerotegumental layer appears damaged (Figure
Twisting setae complicate and obscure observation; use of SEM vital in providing adequate information, while small particles adhering to setal surfaces further complicate observation. In several cases study material presents slight genital neotrichy; in two instances five pairs of setae were observed. One example of neotrichy was observed in Congocepheus, with notogastral neotrichy present in Co. germanicus; but Co. kayoveae is the first observed occurrence of genital neotrichy.
The two species described in this paper are related to Congocepheus taurus
The description given by
Commonalities: Co. taurus and Co. rwandensis are similar in terms of body shape; presence of irregular cord-shaped structures on notogaster; one central vein present on setae c1 and in; e.i.p elevated with in setae situated anteriorly; p.p.d and n.a.d determine a large depression; presence of f.l.p. Co. taurus is similar to Co. kayoveae with regard to the presence of irregular cord-shaped structures on notogaster; c1 setae with one central vein; presence of f.l.p.
Differences: Co. taurus differs from Co. rwandensis in terms of very short c1 setae; e.i.p divided; f.l.p very different in shape; disposition, direction and shape of notogastral setae. Co. taurus differs from Co. kayoveae in terms of body shape; very short setae c1; p.p.d and n.a.d different in shape and size; greatly differing shape of e.i.p; in setae with only one vein; disposition and direction of notogastral setae; f.l.p very different shape.
The complexity of several structures present in species studied, necessitated observation from many different angles, as was the case in Antongilibodes paulae
In Congocepheus kayoveae sp. n. a similar situation was observed to that in Mangabebodes kymatismosi,
Other interesting aspects are the position of the lateral setae (l”) of genu II (Figure
We express much gratitude to Dr Peter Schwendinger, Curator of the Geneva Museum, for his extraordinarily kind assistance and collaboration which allowed us to conduct this study. Our gratitude is also extended to Dr Louwrens Tiedt at the Laboratory for Electron Microscopy, North-West University, South Africa, for his support in obtaining the best quality micrographs. This work is based on research supported in part by the National Research Foundation of South Africa (UID) 85288. Any opinion, findings and conclusions or recommendations expressed in the manuscript are those of the authors and therefore the NRF does not accept any liability in regard thereto.