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. doi: [10.3897/zookeys.556.7011](10.3897/zookeys.556.7011)

Introduction
============

Several species of the genus *Congocepheus* have recently been redescribed, namely *Congocepheus heterotrichus* Balogh, 1958, *Congocepheus orientalis* Mahunka, 1987, *Congocepheus hauseri* Mahunka, 1989 ([@B12]) and *Congocepheus involutus* Mahunka, 1997, with descriptions of new species *Congocepheus gabonensis* [@B14], *Congocepheus ektactesi* [@B14] and *Congocepheus germanicus* [@B13]. A redefinition of *Congocepheus* was given, and the new genus *Cavaecarabodes*, related to *Congocepheus*, was defined and two new species described: *Cavaecarabodes pulchritude* [@B13], and *Cavaecarabodes anouchkai* [@B13].

*Cavaecarabodes* includes some species previously considered members of the genus *Congocepheus*. Type specimens of *Congocepheus ornatus* Mahunka, 1983, *Congocepheus latilamellatus* Mahunka, 1984 and *Congocepheus 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 Natural History Museum of Geneva(NHMG); and from Antilles, Namibia, the Democratic Republic of the Congo, Central African Republic, Tanzania, Ethiopia, Angola, Sudan and South Africa, from the Museum National d'Histoire Naturelle in Paris, France(MNHN). From this material numerous specimens of *Congocepheus* and related genera have been identified. A decision was made to continue with the series of studies of *Congocepheus*, including a number of very interesting new species related to *Congocepheus ornatus*, *Congocepheus latilamellatus* and *Congocepheus velatus*.

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.

Material and methods
====================

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 [@B16] and [@B17]. Drawings were made using a Zeizz GFL (West Germany) compound microscope equipped with a drawing tube.

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 ([@B1], [@B2], [@B3]; [@B5], [@B6], [@B4]; [@B9]). SEM observations were made using a FEI-Quanta Feg 250; with 10 Kv and working distance(WD) variable. Measurements taken: total length (tip of rostrum to posterior edge of notogaster); width (widest part of notogaster) in micrometres (μm).

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 terminology and abbreviations
-------------------------------------------

Morphological terms and abbreviations used are those developed by F. Grandjean (1928--1974) (cf. [@B20]; Norton & Behan-Pelletier (in [@B17]); [@B14]; [@B12]; [@B15]). For setal types [@B8]: 73; and for ornamentation of cuticular surfaces [@B18](in Evans *op.cit*: 9) were used.

New taxa descriptions
=====================

Congocepheus rwandensis sp. n.
------------------------------

Animalia

Oribatida

Carabodidae

http://zoobank.org/6675DD70-7300-426B-A766-0141BFE4C766

[Figures 1--3](#F1){ref-type="fig"} [, 4--6](#F2){ref-type="fig"} [, 7--10](#F3){ref-type="fig"} [, 11--14](#F4){ref-type="fig"} [, 15--18](#F5){ref-type="fig"} [, Table 1](#T1){ref-type="table"}

### Etymology.

The specific epithet is derived from Rwanda, country of origin of the type material.

### Material examined.

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 (MHNG), Switzerland; preserved in 70% ethanol.

Paratype: two adult females, same locality and date as Holotype; deposited in Collection of MHNG; preserved in 70 % ethanol. Material studied for SEM: three specimens, not deposited.

### Diagnosis adult female.

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; *ad~3~* near aggenital setae; anal plate polyhedral, sharply tipped; two pairs of anal setae; lyrifissures *iad* between *ad~3~* and *ad~2~*; conspicuous depressions situated laterally to genital and anal openings.

### Description.

***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 [4](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}).

![*Congocepheus rwandensis* sp. n. Adult female, optical observations. **1** prodorsal zone, anterolateral view **2** partial ventral view **3** dorsal view. Abbreviations: see "Material and methods". Scale bars: (**1, 3**) 100 μm; (**2**) 85 μm.](zookeys-556-019-g001){#F1}

![*Congocepheus rwandensis* sp. n. Adult female, SEM. **4** dorsal view **5** lateral view of bothridial ring and sensillus **6** lateral view *c~1~*, *c~2~* setae. Abbreviations: see "Material and methods". Scale bars: (**4**) 100 μm; (**5**) 10 μm; (**6**) 20 μm.](zookeys-556-019-g002){#F2}

***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 [4](#F2){ref-type="fig"}, [6](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}).

![*Congocepheus rwandensis* sp. n. Adult female, SEM. **7** lateral view, without *c~1~*, *c~2~* setae **8** anterior lateral zone **9** lamellar setae **10** notogastral setae. Abbreviations: see "Material and methods". Scale bars: (**7**) 100 μm; (**8**) 50 μm; (**9, 10**) 10 μm.](zookeys-556-019-g003){#F3}

Absent on: lamellar lateral border (*Lam*), bothridial ring (*bo.ri*), humeral apophysis (*h.ap*) and bothridium (*bo*) (Figures [5](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}, [8](#F3){ref-type="fig"}).

Sometimes absent: ventral depression (*dep*) behind leg IV and notogastral zone between *s.c* and notogastral edge (Figure [7](#F3){ref-type="fig"}).

***Integument*.** Microsculpture: *smooth* to *slightly irregular tuberculate* (Figures [2](#F1){ref-type="fig"}, [3](#F1){ref-type="fig"}, [5](#F2){ref-type="fig"}, [11](#F4){ref-type="fig"}): prodorsal, notogastral and ventral zones. Lateral zone of notogaster presenting slightly larger tubercles. Fingerlike projection (*f.l.p*) clearly visible on central notogastral zone (Figures [2](#F1){ref-type="fig"}, [11](#F4){ref-type="fig"}).

![*Congocepheus rwandensis* sp. n. Adult female, SEM. **11** frontal view **12** rostral setae **13** interamellar setae **14** notogastral setae. Abbreviations: see "Material and methods". Scale bars: (**11**) 100 μm; (**12, 14**) 10 μm; (13) 20 μm.](zookeys-556-019-g004){#F4}

![*Congocepheus rwandensis* sp. n. Adult female, optical observations. **15** leg IV, antiaxial **16** leg I, antiaxial **17** leg II, antiaxial **18** leg III, antiaxial. Abbreviations: see "Material and methods". Scale bar: (**15--18**) 130 μm.](zookeys-556-019-g005){#F5}

On central notogastral zone, network of irregular cord-shaped structures (*c.s.s*) (indicated byX, Figure [2](#F1){ref-type="fig"}) extending to setal insertion zone, *c.s.s* terminating in fingerlike projection (*f.l.p*) on anterior notogastral zone.

***Setation*.** SEM-observations were necessary in order to determine setal shapes. Notogastral and prodorsal setae (*ro*, *in*) (Figures [1](#F1){ref-type="fig"}, [2](#F1){ref-type="fig"}, [6](#F2){ref-type="fig"}, [10](#F3){ref-type="fig"}, [11](#F4){ref-type="fig"}, [12](#F4){ref-type="fig"}, [13](#F4){ref-type="fig"}, [14](#F4){ref-type="fig"}) with elevated medial vein and dentitions; lateral setal margin dentate (Figure [10](#F3){ref-type="fig"}); *ro* setae small (Figures [11](#F4){ref-type="fig"}, [12](#F4){ref-type="fig"}); *in* large directing backwards (Figures [1](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}). In many cases the setae are twisted, immensely complicating observation; the presence of small particles adhering to setal surfaces, further obscuring observation.

Wide, short *le* setae (Figure [9](#F3){ref-type="fig"}) with central vein and dentitions. Notogastral setae with medial dentate veins and dentate margin (Figures [10](#F3){ref-type="fig"}, [14](#F4){ref-type="fig"} central vein indicated by X). Epimeral, genital, aggenital, anal and adanal setae simple, sharply tipped (Figure [3](#F1){ref-type="fig"}).

***Prodorsum*.** Polyhedral (dorsal view) (Figure [2](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}); convex polyhedral in lateral view (Figures [1](#F1){ref-type="fig"}, [7](#F3){ref-type="fig"}); triangular in frontal view (Figure [11](#F4){ref-type="fig"}). Elevated wide interlamellar process (*e.i.p*) (Figures [1](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}, [11](#F4){ref-type="fig"}); *e.i.p* complete, with small depression in medial zone. Anteriorly situated setae *in* on elevated zone of *e.i.p*; *in* setae large (70 ± 5 μm), initially directing forward but tips curving backward; *in* setae inserted antiaxially to medial plane and slightly internally to *ro* insertion level (Figures [1](#F1){ref-type="fig"}, [2](#F1){ref-type="fig"}, [11](#F4){ref-type="fig"}, [13](#F4){ref-type="fig"}). Clearly visible *ro* setae, length 33 ± 3 μm, curving towards medial zone, apical tips adjacent to each other (Figures [9](#F3){ref-type="fig"}, [11](#F4){ref-type="fig"}, [12](#F4){ref-type="fig"}); *le* setae lateral, length 26 ± 3 μm and 12 ± 3 μm in the wider zone (Figure [9](#F3){ref-type="fig"}); *ro* setal insertion at level of *le* setal insertion.

Sensillus (*si*) cylindrical with short barbs (Figure [5](#F2){ref-type="fig"}). Bothridial ring (*bo.ri*) smooth, well defined, with bothridial tooth (Figure [5](#F2){ref-type="fig"}). Posterior prodorsal depressed zone (*p.p.d*) conspicuous, with notogastral anterior depression (*n.a.d*) (Figures [2](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}) delimiting a large depressed area. Rostral margin slightly rounded to hexagonal (Figure [11](#F4){ref-type="fig"}). Lamellae lateral; lamellar tip not observed, shallow lamellar furrow not discernible.

***Notogaster*.** Shape: in dorsal view anterior rectangular, in posterior view oval (Figure [2](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}); in lateral view anterior clearly depressed and rest convex (Figure [7](#F3){ref-type="fig"}); *d.sj* narrow, slightly rectilinear, well delimited; notogastral anterior depression (*n.a.d*) small (Figures [2](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}).

Fourteen pairs of setae: *c*~1~, *c*~2~, *da*, *dm*, *dp*, *la*, *lm*, *lp*, *h*~1~, *h*~2~, *h*~3~, *p*~1~, *p*~2~, *p*~3~; *c*~1~ setae directing forward (Figures [2](#F1){ref-type="fig"}, [6](#F2){ref-type="fig"}), other setae directing backward (Figures [2](#F1){ref-type="fig"}, [4](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}), *c*~1~ largest; *h*~3~, *p*~1~, *p*~2~, *p*~3~ smaller; c~2~, *da*, *dm*, *dp*, *la*, *lm*, *la*, *h*~1~, *h*~2~ more or less equal in length. Series of irregular *c.s.s* in central zone converging to form a short *f.l.p* (Figure [2](#F1){ref-type="fig"}). Circumgastric depression (*s.c*) situated in front of *p*~1~, *p*~2~, *p*~3~, *h*~3~ setae (Figure [4](#F2){ref-type="fig"}) clearly visible in posterior notogastral area). Humeral apophysis (*h.ap*) very long, clearly visible as large elongate projection resulting in characteristic shape of anterior notogastral zone (Figure [4](#F2){ref-type="fig"}).

***Lateral region*** (Figure [7](#F3){ref-type="fig"}). Lamellae (*lam*) well discernible, more or less truncate; cuticular surface of lamellar zone smooth, always without cerotegumental layer. Tutorium (*tu*) a prominent curving lamina, margin clearly discernible, smooth cuticula.

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 [5](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}); smooth bothridial ring (*bo.ri*) wider in inferior zone, *bo.ri* incomplete with bothridial tooth, clearly discernible. Sensilllus cylindrical with barbs arching toward the tip (Figures [5](#F2){ref-type="fig"}, [7](#F3){ref-type="fig"}). Humeral apophysis (*h.ap*): elongate extended structure, rounded apex, basally curved; anterior tip overlapping posterior bothridial part. Clearly visible large depression (*dep*) behind leg IV; two other *dep* present in lateral and posterior anal zones.

***Ventral region*** (Figure [3](#F1){ref-type="fig"}). Epimera slightly elevated, delimited by a narrow but deep furrow (*bo.1*, *bo.2*, *bo.sj*). Epimera 4 fused, epimeral furrow (*bo.3*) narrow; *apo.1*, *apo.2*, *apo.sj* and *apo.3* well discernible.

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; *ad~3~* close to *ag* setae. Anal plate polyhedral, sharply tipped. Two pairs of anal setae. Lyrifissures *iad* well discernible, situated laterally between *ad~3~* and *ad~2~*. Depressions (*dep*) clearly visible, situated laterally to genital and anal openings.

***Legs*** (Figures [9](#F3){ref-type="fig"}--[12](#F4){ref-type="fig"}). All legs monodactyle. Setal formulae I (1-3-2-3-16-1) (1-2-2); II (1-4-3-3-15-1) (1-1-2); III (2-3-1-2-14-1) (1-1-0); IV (1-2-2-3-13-1) (0-1-0). See Table [1](#T1){ref-type="table"}.

###### 

*Congocepheus rwandensis* sp. n. setae and solenidia.

  ------------- ------------------- -------------- -------------- -------------------------------------------------------- ------
  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              φ~1~, φ~2~     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              \-                                                       
  ------------- ------------------- -------------- -------------- -------------------------------------------------------- ------

### Remarks.

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.

Congocepheus kayoveae sp. n.
----------------------------

Animalia

Oribatida

Carabodidae

http://zoobank.org/BFD45F16-4D42-4684-81C2-17A3D5F723C7

[Figures 19--24](#F6){ref-type="fig"} [, 25--28](#F7){ref-type="fig"} [, 29--33](#F8){ref-type="fig"} [, 34--38](#F9){ref-type="fig"} [, 39--43](#F10){ref-type="fig"} [, 44--47](#F11){ref-type="fig"} [; Table 2](#T2){ref-type="table"}

### Etymology.

The specific epithet is derived from Kayove, Rwanda, where the type material was collected.

### Material examined.

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 (MHNG), Switzerland; preserved in 70% ethanol. Four adult female paratypes, same locality and date as holotype; deposited in Collection of MHNG; preserved in 70 % ethanol. Material studied by SEM: six specimens, not deposited.

### Diagnosis adult female.

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 *ad~3~*.

### Description.

***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 [19](#F6){ref-type="fig"}). ***Colour*.** Specimens without cerotegument; light brown to yellowish-brown when observed in reflected light.

![*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.](zookeys-556-019-g006){#F6}

***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 [19](#F6){ref-type="fig"}, [21](#F6){ref-type="fig"}, [22](#F6){ref-type="fig"}, [23](#F6){ref-type="fig"}, [24](#F6){ref-type="fig"}). Observation of cuticular ornamentation not impeded by cerotegumental layer (Figures [20](#F6){ref-type="fig"}, [22](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}). Absent: bothridial ring (*bo.ri*) (Figure [20](#F6){ref-type="fig"}).

![*Congocepheus kayoveae* sp. n. Adult female, optical observations. **25** dorsal view **26** prodorsum, frontal inclined view **27** prodorsum, dorsal inclined view **28** lateral view. Abbreviations: see "Material and methods". Scale bars: (**25, 28**) 220 μm; (**26, 27**) 80 μm.](zookeys-556-019-g007){#F7}

![*Congocepheus kayoveae* sp. n. Adult female, SEM. **29** lateral view **30** frontal inclined view **31** lateral inclined view **32** notogastral setae **33** damaged cerotegumental layer. Abbreviations: see "Material and methods". Scale bars: (**29**) 100 μm; (**30--31**) 50 μm; (**32**) 10 μm; (**33**) 5 μm.](zookeys-556-019-g008){#F8}

***Integument*.** *Pusticulate* (Figure [22](#F6){ref-type="fig"}): prodorsum: *e.i.p* posterior zone, lamellar margin and bothridial zone; central notogastral zone and humeral apophysis (Figures [19](#F6){ref-type="fig"}, [20](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}); legs: femurs (Figure [38](#F9){ref-type="fig"}). Smooth to granulate: prodorsum: anterior *e.i.p* (Figure [19](#F6){ref-type="fig"}); notogaster: *s.c*, *b.ng* zone (Figure [29](#F8){ref-type="fig"}); lateral zone: *Tu*, *s.tu.d*, *Pd I*, *Pd II*. Ventral zone: subcapitulum, epimeral, genital, anal and *dep* (Figures [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}, [34](#F9){ref-type="fig"}, [39](#F10){ref-type="fig"}, [40](#F10){ref-type="fig"}, [41](#F10){ref-type="fig"}, [42](#F10){ref-type="fig"}). Series of irregular *c.s.s.* on notogastral zone, forming central elongate *f.l.p* (Figures [25](#F7){ref-type="fig"}, [28](#F7){ref-type="fig"}) (described in detail under notogaster), well visible without cerotegumental layer.

![*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.](zookeys-556-019-g009){#F9}

![*Congocepheus kayoveae* sp. n. Adult female SEM. **39** ventral view **40** genital plate **41** anal zone **42** genital plate, lateral view **43** epimeral setae. Abbreviations: see "Material and methods". Scale bars: (**39**) 100 μm; (**40, 42, 43, 44**) 10 μm; (**38, 41**) 20 μm.](zookeys-556-019-g010){#F10}

![*Congocepheus kayoveae* sp. n. Adult female, optical observations. **44** leg I antiaxial **45** leg IV, antiaxial **46** leg III, antiaxial **47** leg II antiaxial. Abbreviations: see "Material and methods". Scale bar: (**44--47**) 100 μm.](zookeys-556-019-g011){#F11}

***Setation*.** *Simple*: epimeral (Figures [39](#F10){ref-type="fig"}, [43](#F10){ref-type="fig"}), genital (Figures [40](#F10){ref-type="fig"}, [42](#F10){ref-type="fig"}), aggenital (Figure [42](#F10){ref-type="fig"}), anal, adanal (Figure [41](#F10){ref-type="fig"}), subcapitular (Figure [34](#F9){ref-type="fig"}) and seta of genu, tibia and tarse of legs. *One central dentate vein and dentate margin*: notogastral (Figures [32](#F8){ref-type="fig"}, [37](#F9){ref-type="fig"}); two types of notogastral setae: large *c~1~*, *c~2~*, *dp*, *h~1~*, with upward directing dentate margin (Figure [37](#F9){ref-type="fig"}); small *da*, *dm*, *la*, *lm*, *lp*, *h~2~*, *h~3~*, *p~1~*, *p~2~*, *p~3~*, dentate margin not directing upward (Figure [32](#F8){ref-type="fig"}). *Two dentate veins and dentate margin* (Figures [21](#F6){ref-type="fig"}, [24](#F6){ref-type="fig"}), *ro* (Figure [21](#F6){ref-type="fig"}), *in* setae (Figure [24](#F6){ref-type="fig"}). *Flat setae, dentate margin with central dentate vein*: *le* setae (Figure [36](#F9){ref-type="fig"}), superior margin presenting few teeth; numerous large teeth on inferior margin. *Barbate, with central dentition*: large femoral setae (legs I-IV) (Figure [38](#F9){ref-type="fig"}).

***Prodorsum*.** Polyhedral (dorsal view) (Figure [19](#F6){ref-type="fig"}); slightly convex polyhedral in lateral view (Figure [29](#F8){ref-type="fig"}); triangular in frontal view (Figure [35](#F9){ref-type="fig"}). Elevated interlamellar process (*e.i.p.*) almost flat in dorsal view (Figures [19](#F6){ref-type="fig"}, [25](#F7){ref-type="fig"}); large surface between *p.p.d* and *in* setae insertion zone (Figures [19](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}), flat in frontal view (Figure [35](#F9){ref-type="fig"}) (see Remarks); *in* setae (Figure [24](#F6){ref-type="fig"}) large (82 μm ± 5), curving, directing backward (Figures [19](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}), setae inserted anteriorly on *e.i.p.* (Figures [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}) at same longitudinal level as *ro* insertion (Figure [35](#F9){ref-type="fig"}); *ro* setae (Figure [21](#F6){ref-type="fig"}) length (38 μm ±3 μm), directing forward and paraxially (Figures [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}), curving downward (Figures [29](#F8){ref-type="fig"}, [36](#F9){ref-type="fig"}) with criss-crossing tips (Figures [21](#F6){ref-type="fig"}, [30](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}); *le* setae lateral (Figures [29](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}, [36](#F9){ref-type="fig"}), length (58 μm ± 3), wider zone (10 μm ± 2); *ro* and *le* setal insertion at same level.

Sensillus (*si*) (Figure [20](#F6){ref-type="fig"}) (66 μm ± 3) uncinate, curving upward (Figures [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}). Bothridial ring (*bo.ri*) smooth, well defined, with bothridial tooth (Figure [20](#F6){ref-type="fig"}).

Rostral margin slightly rounded, margin undulate (Figure [30](#F8){ref-type="fig"} indicated byJ; 35 indicated by Y).

Lamellae running dorsolaterally (Figures [26](#F7){ref-type="fig"}, [27](#F7){ref-type="fig"}); semicircular shallow lamellar furrow (*l.l.f*) originating on bothridial zone and terminating near lamellar tip (*la.ti*), clearly discernible when cerotegumental layer absent (Figures [26](#F7){ref-type="fig"}, [27](#F7){ref-type="fig"}). Posterior prodorsal depressed zone (*p.p.d*) large, normal (Figures [19](#F6){ref-type="fig"}, [25](#F7){ref-type="fig"}).

***Notogaster*.** Ovoid in dorsal view, with slight constriction at level of *da*, *la* setae (Figure [19](#F6){ref-type="fig"}); in lateral view zone anterior to *da*, *la* setae slightly depressed, rest convex (Figure [29](#F8){ref-type="fig"}); *d.sj* narrow, slightly rectilinear, well delimited (Figure [25](#F7){ref-type="fig"}); notogastral anterior depression (*n.a.d*) reduced (Figures [19](#F6){ref-type="fig"}, [25](#F7){ref-type="fig"}).

Fourteen pairs of setae: *c*~1~, *c*~2~, *da*, *dm*, *dp*, *la*, *lm*, *lp*, *h*~1~, *h*~2~, *h*~3~, *p*~1~, *p*~2~, *p*~3~; *c*~1~ (86 ± 5 μm); c~2~ (75 ± 5 μm) both setae long and thin, direction variable but in most cases directing forward (Figure [19](#F6){ref-type="fig"}, [31](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}), however not uncommon for these setae to be directing backward (Figure [29](#F8){ref-type="fig"}). Setae *da* (35 ±3 μm); *dm* (30 ± 3 μm); *dp* (65 ± 3 μm); *la* (35 ± 3 μm); *lm* (27 ± 3 μm); *lp* (42 ± 3 μm); *h*~1~ (48 ± 3 μm); *h*~2~ (45 ± 3 μm); *h*~3~ (25 ± 3 μm); *p*~1~ (13 ± 3 μm); *p*~2~ (15 ± 3 μm); *p*~3~ (17 ± 3 μm).

Cord-shaped structures (*c.s.s*) converging in central anterior zone forming an elongate fingerlike projection (*f.l.p*) (53 ± 5 μm (Figure [25](#F7){ref-type="fig"}). Circumgastric depression (*s.c*) present, clearly visible (Figures [19](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}), from *h.ap* surrounding notogaster, situated between *la*, *lm* , *lp*, *h~2~*, *h~1~* and *h~3~*, *p~3~*, *p~2~*, *p~1~* setae (Figure [19](#F6){ref-type="fig"}). Humeral apophysis (*h.ap*) large elongate projection (Figure [19](#F6){ref-type="fig"}).

***Lateral region*** (Figures [29](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}). Lamellae (*lam*) easily discernible; cuticular microsculpture near bothridial zone pusticulate with several round depressions (Figure [20](#F6){ref-type="fig"}); *le* setal insertion at same level as *ro* setal insertion; conspicuous *la.ti* (Figures [25](#F7){ref-type="fig"}, [26](#F7){ref-type="fig"}, [35](#F9){ref-type="fig"}) (details in frontal view).

Tutorium (*tu*) prominent lamina, curving margin, clearly discernible, smooth cuticula (Figures [29](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}). Deep supratutorial depression (*s.tu.d*) running parallel to and between lamellae and tutorium; *p.tu.d* and *a,tu d* present, large (Figure [31](#F8){ref-type="fig"}). *Tu* larger than *Pd I*, expanded laterally (Figure [31](#F8){ref-type="fig"}).

Bothridial ring (*bo.ri*) smooth, with *bo.to*, hardly discernible due to positioning of lateral antiaxial setae (*l*") of genu II (Figure [20](#F6){ref-type="fig"}) (see Remarks); *h.ap* triangular, inferior margin rounded; anterior zone of *h.ap* overlapping posterior bothridial zone (Figures [20](#F6){ref-type="fig"}, [29](#F8){ref-type="fig"}).

Clearly delimited zone on *s.c* with more or less smooth cuticula, immediately followed by clearly delimited pusticulate zone (Figure [29](#F8){ref-type="fig"}), and slightly below insertion of setae *h~3~*, *p~3~*, *p~2~*, *p~1~* to *h.ap*, a smooth zone extending to *b.ng*. Clearly delimited depressed zone behind leg IV. Cuticular ribbon (Figure [29](#F8){ref-type="fig"} indicated by X) parallel to *b.ng*.

***Frontal view*** (Figures [26](#F7){ref-type="fig"}, [27](#F7){ref-type="fig"}, [30](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}). Actual shape and disposition of: *e.i.p*, *in* setae, *Lam*, *le* setae, *la.ti*, *Tu*, *Pd I*, *s.tu.d.* and characteristics of rostral margin visible in frontal view.

Complete, flat *e.i.p* (Figure [35](#F9){ref-type="fig"}); *in* setae placed far from *e.i.p* margin; *Lam* present slightly higher up on margin, terminating anteriorly in large triangular *la.ti*, with *le* setae situated in the external limit of *la.ti* (Figures [30](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}) and the *l.l.f* terminating near internal limit of *la.ti* (Figure [26](#F7){ref-type="fig"}, [27](#F7){ref-type="fig"}). Insertions of *ro* and *le* setae at the same transverse level (Figure [34](#F9){ref-type="fig"}). The *l.l.f* is only clearly discernible under optical observation (Figures [26](#F7){ref-type="fig"}, [27](#F7){ref-type="fig"}); in SEM observation the zone between *l.l.f* and lamellar margin is a slightly flat zone (Figure [30](#F8){ref-type="fig"}). Laterally expanded spoon-shaped *Tu* appearing larger than *Pd I* (Figures [30](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}); very deep *s.tu.d* completely concealing leg I (Figure [30](#F8){ref-type="fig"}). Rounded, undulate rostral margin with prominent forward extension, parallel to *Tu*, extending backward *Pd I* level (Figures [30](#F8){ref-type="fig"}, [35](#F9){ref-type="fig"}) (See Discussion).

***Ventral region*** (Figures [34](#F9){ref-type="fig"}, [39](#F10){ref-type="fig"}, [40](#F10){ref-type="fig"}, [41](#F10){ref-type="fig"}, [42](#F10){ref-type="fig"}, [43](#F10){ref-type="fig"}). Large, clearly discernible rostral margin (Figure [34](#F9){ref-type="fig"} indicated by X). Elevated epimera delimited by deep furrow (Figure [39](#F10){ref-type="fig"}); deep hollow zone paraxial to epimere 1(Figure [39](#F10){ref-type="fig"}, indicated by K); complete epimere *sj*; epimera 3 and 4 well discernible, unfused. Epimeral chaetotaxy 3-1-3-3. Epimeral setae *1a*, *2a*, *3a*, *4a*, largest. Discidum clearly discernible; *a.g.f* clearly visible, situated anterior to genital plate (Figure [40](#F10){ref-type="fig"}). Genital plate rounded, with four or five pairs of genital setae, (see Remarks) (Figures [40](#F10){ref-type="fig"}, [42](#F10){ref-type="fig"}); all setae more or less equal in length; *ag* setae situated posterior to genital opening, far from *ad~3~* (Figure [39](#F10){ref-type="fig"}). Three pairs of *ad* seta, more or less equal in length (Figure [41](#F10){ref-type="fig"}); anal plate polyhedral (Figure [41](#F10){ref-type="fig"}), sharply tipped; two pairs of anal setae; anterior pairs larger than posterior. Shallow depressions (*dep*) (Figure [39](#F10){ref-type="fig"}) situated laterally on either side of as well as between genital and anal openings. Subcapitulum diarthric (Figure [34](#F9){ref-type="fig"}); setae *h* largest.

***Legs*** (Figures [44--47](#F11){ref-type="fig"}). All legs monodactyle. Setal formulae I (1-4-2-4-16-1) (1-2-2); II (1-3-3-3-15-1) (1-1-2); III (2-3-1-2-14-1) (1-1-0); IV (1-2-2-3-12-1) (0-1-0). See Table [2](#T2){ref-type="table"}.

###### 

*Congocepheus kayoveae* sp. n. setae and solenidia.

  ------------- ----------------------- -------------- ----------------- --------------------------------------------------------------- ------
  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*            *φ~1~*, *φ~2~*    *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                 \-                                                              
  ------------- ----------------------- -------------- ----------------- --------------------------------------------------------------- ------

### Remarks.

In some specimens the cerotegumental layer appears damaged (Figure [33](#F8){ref-type="fig"}), as more than 40 years have passed since collection, preservation of specimens may have been influenced by the quality of the initial diluted alcohol. Material of much greater age has been studied previously without problems, but in this case, the description of the cerotegumental layer must be regarded as provisional.

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 *Congocepheus germanicus*; but *Congocepheus kayoveae* is the first observed occurrence of genital neotrichy.

Discussion
==========

The two species described in this paper are related to *Congocepheus taurus* [@B7]. Unfortunately, as we were unable to obtain the type material, *Congocepheus taurus* is the only species within the genus *Congocepheus* we were unable to study. The type locality given by Balogh is "Africa Orientalis: Meru", and searching through our material from Tanzania, we were unable to locate this species.

The description given by [@B7] (page 522) is short and imprecise with only two figures, 10 (dorsal) and 11 (lateral) (page 523); figures lack detail, with important omissions. The following comparison is confined to an analysis of characters and figures provided by the author in 1961.

Commonalities: *Congocepheus taurus* and *Congocepheus rwandensis* are similar in terms of body shape; presence of irregular cord-shaped structures on notogaster; one central vein present on setae *c~1~* 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*. *Congocepheus taurus* is similar to *Congocepheus kayoveae* with regard to the presence of irregular cord-shaped structures on notogaster; *c~1~* setae with one central vein; presence of *f.l.p*.

Differences: *Congocepheus taurus* differs from *Congocepheus rwandensis* in terms of very short *c~1~* setae; *e.i.p* divided; *f.l.p* very different in shape; disposition, direction and shape of notogastral setae. *Congocepheus taurus* differs from *Congocepheus kayoveae* in terms of body shape; very short setae *c~1~*; *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* [@B15] and *Mangabebodes kymatismosi* [@B15]. In the description of *Congocepheus kayoveae* sp. n., Figures [29](#F8){ref-type="fig"}, [30](#F8){ref-type="fig"}, [31](#F8){ref-type="fig"}, and [34](#F9){ref-type="fig"} are complementary; lateral, frontal and frontal inclined views permit understanding of several characteristics and aspects not clearly observed (or difficult to interpret) in only the lateral or ventral position. Succinct studies such as that of *Congocepheus taurus*, with a short description and poorly developed figures, confound comparison, and several particularities of this species may go unnoticed.

In *Congocepheus kayoveae* sp. n. a similar situation was observed to that in *Mangabebodes kymatismosi*, [@B15]; where the *tutorium* forms a prominent lateral expansion and is relatively large; considered to be the first instance where this particularity is observed in *Congocepheus*. In *Congocepheus kayoveae* sp. n., the *s.tu.d* is very deep, completely concealing leg I.

Other interesting aspects are the position of the lateral setae (*l*") of genu II (Figure [20](#F6){ref-type="fig"}), which during the leg folding process (See [@B12]) protect the opening of the bothridium, and the perfect coaptation of the legs and depressions during leg folding (Figure [29](#F8){ref-type="fig"}).

Supplementary Material
======================

###### XML Treatment for Congocepheus rwandensis

###### XML Treatment for Congocepheus kayoveae

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.

[^1]: Academic editor: V. Pesic
