Congocepheus rwandensis, Fernandez, Nestor, Theron, Pieter & Leiva, Sergio, 2016

Fernandez, Nestor, Theron, Pieter & Leiva, Sergio, 2016, Revision of the family Carabodidae (Acari, Oribatida) V. Fourth part. Two new species of the genus Congocepheus from the Republic of Rwanda: Congocepheusrwandensis sp. n., and Congocepheuskayoveae sp. n., ZooKeys 556, pp. 19-41 : 20-25

Taxon classification Animalia Oribatida Carabodidae

Congocepheus rwandensis sp. n. Figures 1-3, 4-6, 7-10, 11-14, 15-18, Table 1

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; 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.

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, 7).

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, 6, 7).

Absent on: lamellar lateral border (Lam), bothridial ring (bo.ri), humeral apophysis (h.ap) and bothridium (bo) (Figures 5, 7, 8).

Sometimes absent: ventral depression (dep) behind leg IV and notogastral zone between s.c and notogastral edge (Figure 7).

Integument. Microsculpture: smooth to slightly irregular tuberculate (Figures 2, 3, 5, 11): 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, 11).

On central notogastral zone, network of irregular cord-shaped structures (c.s.s) (indicated byX, Figure 2) 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, 2, 6, 10, 11, 12, 13, 14) with elevated medial vein and dentitions; lateral setal margin dentate (Figure 10); ro setae small (Figures 11, 12); in large directing backwards (Figures 1, 4). 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) with central vein and dentitions. Notogastral setae with medial dentate veins and dentate margin (Figures 10, 14 central vein indicated by X). Epimeral, genital, aggenital, anal and adanal setae simple, sharply tipped (Figure 3).

Prodorsum. Polyhedral (dorsal view) (Figure 2, 4); convex polyhedral in lateral view (Figures 1, 7); triangular in frontal view (Figure 11). Elevated wide interlamellar process (e.i.p) (Figures 1, 4, 7, 11); 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, 2, 11, 13). Clearly visible ro setae, length 33 ± 3 μm, curving towards medial zone, apical tips adjacent to each other (Figures 9, 11, 12); le setae lateral, length 26 ± 3 μm and 12 ± 3 μm in the wider zone (Figure 9); ro setal insertion at level of le setal insertion.

Sensillus (si) cylindrical with short barbs (Figure 5). Bothridial ring (bo.ri) smooth, well defined, with bothridial tooth (Figure 5). Posterior prodorsal depressed zone (p.p.d) conspicuous, with notogastral anterior depression (n.a.d) (Figures 2, 4, 7) delimiting a large depressed area. Rostral margin slightly rounded to hexagonal (Figure 11). Lamellae lateral; lamellar tip not observed, shallow lamellar furrow not discernible.

Notogaster. Shape: in dorsal view anterior rectangular, in posterior view oval (Figure 2, 4); in lateral view anterior clearly depressed and rest convex (Figure 7); d.sj narrow, slightly rectilinear, well delimited; notogastral anterior depression (n.a.d) small (Figures 2, 4).

Fourteen pairs of setae: c1, c2, da, dm, dp, la, lm, lp, h1, h2, h3, p1, p2, p3; c1 setae directing forward (Figures 2, 6), other setae directing backward (Figures 2, 4, 7), c1 largest; h3, p1, p2, p3 smaller; c2, da, dm, dp, la, lm, la, h1, h2 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). Circumgastric depression (s.c) situated in front of p1, p2, p3, h3 setae (Figure 4) 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).

Lateral region (Figure 7). 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, 7); 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, 7). 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). 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; 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 9-12). 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.

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.