Ishèko (Pobè District, Ouémé drainage basin), Well Pb5: West from Pobè center along the principal road to Kétou District (details in Table 3).

Female holotype, dissected and mounted on 3 slides (RBINSc COP 10.304A-C), allotype male, dissected and mounted on 3 slides (RBINSc COP 10.305A-C), 1 female paratype dissected on 2 slides (RBINSc COP 10.306A-B) and 4 females, 5 males and 4 juveniles preserved (RBINSc COP 10.307), all collected 26/07/2012; additional paratypic material: 3 females, 4 males, 5 juveniles (preserved material RBINSc COP 10.353), topotypic, collected 16/04/2013.

derived from the Latin words spinula and ferre, respectively meaning small thorn and to carry, and referring to the spinular ornamentation on pediger 5, on leg 4 and on the caudal rami.

(1) Pobè District, Ouémé drainage basin:

– Well Pb6: 07/02/11: 6 ♀♀, 2 ♂♂ and 2 CV copepodids (♀ dissected RBINSc COP 10.308A-C, preserved material RBINSc COP 10.309); 27/11/2012: 19 ♀♀, 5 ♂♂, 1 CIV & 1 CV ♀ (CV dissected RBINSc COP 10.386A-B, preserved material RBINSc COP 10.327); 04/03/2013: 21 ♀♀, 11 ♂♂, 5 juveniles (preserved material RBINSc COP 10.339); 26/11/2012: 2 ♀♀ (preserved material RBINSc COP 10.377); 20/09/2013: 9 ♀♀, 2 ♂♂ (preserved material RBINSc COP 10.376).

– Well Pb12: 24/07/2012: 3 ♀♀, damaged (preserved material RBINSc COP 10.328).

(2) Zogbodomè District, Ouémé drainage basin:

– Well Zogbodomè: 21/10/2009: 2 ♀♀, 1 ♂ (preserved material RBINSc COP 10.387).

Female. Habitus (Fig. 2A) typically cyclopid with prominent prosome, 1.6 times longer than urosome. Body length 1175 μm (holotype), ranging from 1075 to 1200 μm (n=5). Urosome rather narrow, compared to wide cephalothorax and pediger 2. Urosomite 1 (pediger 5) with cluster of long and rigid spinules on the lateral and ventrolateral surface (Fig. 3D). Genital double-somite widest in anterior third, with distinct constriction of lateral margins in anterior half and a L/W ratio: 1/1.25. Ventral surface with, in frontal third, a transverse undulate ridge parallel with lateral arms of genital complex (dotted line between arrows in Fig. 3A) and, caudally from copulatory pore, some crescent ridges. Posterodorsal fringe of prosomites 1–3 narrow and un-incised, of prosomite 4 and first urosomite narrow and discretely serrate. Posterior margin of genital double-somite and urosomites 4–5 wide and serrate, coarsely incised. Anal somite with smooth crescent operculum and large anal sinus. The latter with an oblique row of minute and slender spinules on either side of the anal slit. Posterior margin of anal somite with uninterrupted row of spinules. Dorsal and lateral surface of urosomites adorned with minute, hardly visible spinules. Ventral surface of anal somite with an irregular pattern of slightly larger spinules.

Caudal rami (Fig. 2D) cylindrical, 2.7–3.0 times longer than wide, with distinct triangular depression in anterior half of medial margin. Anterolateral seta short, pinnate, and inserted in posterior half, without spinules at insertion. Distolateral element slightly longer than ramus (ratio 1.2–1.3/1) and longer than medial terminal element (ratio 1.2–1.4/1). Distolateral element with widely spaced long and slender spinules along outer side of stem, with widely spaced setules along inner side; spinules present near its insertion. Medial element as long as caudal ramus, and pinnate. Dorsal seta, articulating on small basal part, shorter than ramus (ratio 0.8–0.9/1). Principal terminal caudal setae pinnate, with breaking plane present in both. Surface of rami with irregular and defuse pattern of minute spinules on dorsal and ventral side, triangular anteromedial depression clearly delimited dorsally.

Antennule 11-segmented, not reaching beyond cephalothorax, and having the typical armature distribution i.e.: 1(8)-2(4)-3(6)-4(2)-5(2)-6(2)-7(3)-8(2+Aesth.)-9(2)-10(2+Aesth.)-11(7+Aesth). First segment with crescent row of slender spinules in proximal half (Fig. 4A). Aesthetasc on segment 8 half as long as accompanying seta, linguiform, and reaching just beyond distal margin of segment 8. Aesthetasc on segment 10 filiform, shorter than accompanying element and extending to middle of terminal antennulary segment. Terminal aesthetasc tubular, slightly longer than segments 10–11 combined, and fused at base with seta; both equally long (Fig. 4B).

Antennal general aspect and armature as in A. cavicola: i.e.: 4-segmented, short exopodal seta, 2 abexopodal setae, first endopodite segment with 1, second one with 9, and ultimate segment with 7 elements. Frontal surface of coxobasis (Fig. 5A) with 2 rows of coarse spinules parallel to outer margin (proximal one with 10–12, distal one with 9–10 spinules) and short proximal transverse row of tiny spinules near abexopodal margin. Caudal surface (Fig. 5B, C) with 3 clusters of long and slender spinules in proximal half: 2 clusters near outer margin, 1 near inner margin.

Mandible, maxillule and maxilliped as in A. cavicola. General aspect of maxilla as in A. cavicola. Medial claw of maxillary basis (Fig. 4I) long and blunt, armed with 4 large teeth increasing in length medially. Accessory seta as long as claw, serrate on both sides in proximal half, on one side in distal half. Both elements on first endopodite segment with set of large spinules in middle. Distal half either smooth or with minute spinules along both sides of the stem. Terminal element on second endopodite segment articulating on segment, furnished with minute spinules along one side of the stem. Both lateral elements on second segment slender and naked.

Legs 1–4 protopodite (Fig. 6A, C, D, F, G). Praecoxa of legs 1–3 with short row of slender spinules along distal margin close to outer edge. Praecoxa of leg 4 smooth. Outer part of coxa with 2 (legs 1–3) or 3 (leg 4) short rows of spinules on frontal surface. Coxal caudal surface of legs 1–3 with set of spinules near proximal outer edge (see ex. for leg 2: Fig. 6D). Medial coxal seta of legs 1–4 pinnate and reaching beyond proximal endopodite segment. Intercoxal sclerites unadorned on both sides. Lateral distal edges crescent without ornamentation. Mediodistal region concave (legs1–3: Fig. 6B) or nearly straight (leg 4). Inner edge of leg 1 basis crescent, of legs 2–4 produced in sharp triangular process. Medial margin hairy in legs 1–3, naked in leg 4. Inner element on leg 1 basis present, serrate and reaching beyond proximal endopodite segment, but not beyond middle of distal segment. Outer element on basis of the legs setiform: longest on leg 1 basis, shortest one on basis of leg 2.

Legs 1–4 with 2-segmented rami (Fig. 6A, C, F, G). Exopodite and endopodite equally long. Rami with the following armament distribution:

EXO END

Leg 1 I,1 - III,2,3 0,1 - 1,I+1,3

Leg 2 I,1 - III,I+1,4 0,1 - 1,I+1,4

Leg 3 I,1 - III,I+1,4 0,1 - 1,I+1,4

Leg 4 I,0 - II,I+1,4 0,1 - 1,II,3

Outer distal edge of second endopodite segment of legs 1–3 distinctly protruded, of leg 4 small and as large as inner one. Frontal and caudal surface of leg segments of legs 1–2 and frontal surface of leg 3 unadorned. Caudal surface of distal endopodite segment of leg 3, and frontal and caudal surface of leg 4 segments with diffuse pattern of tiny spinules.

Caudal surface of proximal endopodite segment of leg 4 inflated. Distal endopodite segment of leg 4 twice as long as wide with inner terminal spine as long as segment. Outer terminal spine slightly longer than half inner one (ratio: 0.55–0.56). Inner terminal spine set with long slender spinules. Outer subdistal and inner setae, equally long, not reaching noticeably beyond longest (outer) terminal spine.

Leg 5 (Fig. 3E) confluent with pediger, represented by narrow crescent expansion. Ancestral basal segment represented by long pinnate element, and ancestral distal segment marked by narrow truncate elevation, bearing 2 elements: setiform outer one, spiniform medial one, the latter twice as long as the former.

Leg 6 vestiges located laterally with 3 elements: dorsal one short and setiform, middle and ventral one dwarfed, blunt triangular, with hyaline appearance. Valves unadorned. Copulatory pore located midventrally in anterior third of somite, leading to U-shaped duct (Fig. 3C). Anterior receptacle expanded with undulate frontal margin. Posterior receptacle produced caudally extending to middle of double-somite, bilobed. Lateral arms (= narrow canal-like rim extending from copulatory duct to genital aperture) straight.

Male. Habitus (Fig. 2C) as in female, but with narrower prosome and 6-segmented urosome. Body length: 1000 μm (allotype), ranging from 807–1000 μm (n=5). Integumental ornamentation, fringe structure and L/W ratio of caudal rami as in the female (2.7–3.0/1). Armature: distolateral element 1.27–1.30 times longer than ramus, terminal medial element nearly 0.9–1.0 times ramal length, dorsal seta as long as ramus.

Antennule as described for A. cavicola: i.e.16-segmented with the following armature distribution: 1(8+3 Aesth.)-2(4)-3(2)-4(1)-5(2)-6(2)-7(2)-8(2)-9(2+Aesth.)-10(2)-11(2)-12(2)-13(1+Aesth.)-14(4)-15(3)-16(11+Aesth.). Aesthetascs on segment 1, 9 and 13 long, narrow and linguiform. Mouthparts as in the female. Legs 1–4 with general structure and armature as in the female, but terminal segment of endopodites slightly narrower (see ex. for leg 3: Fig. 6H) and leg 4 proximal endopodite segment not expanded caudally.

Leg 5 (Fig. 3D) with expansion representing distal segment more accentuated than in female. Proportional lengths of armament as in the female. Spinule ornamentation on lateral and ventral surface of pediger less dense than in the female.

Leg 6 (Fig. 3B) represented as a large, unadorned, valve with outer distal edge distinctly produced bearing 2 elements: outer one setiform, half as long as medial spiniform element.

Animals from Well Pb 6 collected on 07/02/2011 are smaller with the body length of the females ranging from 875 to 1009 μm, that of the males between 890–895 μm. They display shorter caudal rami (L/W ratio 1/2.6–2.7) with slightly longer setae: distolateral one 1.3–1.4 times longer than the ramus, and medial terminal element 1.1–1.3 times longer than ramus. In all other respects they resemble A. spinifer sp. n. as described above.

Guéma, Parakou District, Ouémé drainage basin: Well C2 (details in Table 2).

Female holotype, dissected and mounted on 3 slides (RNBNSc COP 10.313A-C), allotype male, dissected and mounted on 2 slides (RBINSc COP 10.312A-B), paratypes: 11 females and 2 males preserved in alcohol (RBINSc COP 10.314), all collected 07/03/2013; and additional (topotypic) paratypes collected on 13/02/2011: 4 females, 1 male, 1 juvenile; on 08/03/2013: 37 females, 15 males, 7 juveniles (preserved material RBINSc COP 10.340).

From the Latin word “pilus” meaning hair and refers to the rows of delicate hairs along the medial margin of the caudal rami.

(1) Parakou District, Ouémé drainage basin:

– Well A1: 10/07/12: 5 ♀♀, 1 CV juvenile ♀ (preserved material RBINSc COP 10.321);

– Well B6: 26-10-11: 1 ♀ (preserved material RBINSc COP 10.320); RBINSc COP 10.311);

– Well C6: 13/12/10: 11 ♀♀ (dissected ♀ RBINSc COP 10.316A-B, preserved material RBINSc COP 10.317; 29/10/2011: 33 ♀♀, 1 juvenile (preserved material RBINSc COP 10.342).

(2) Pobè, Plateau District, Ouémé drainage basin:

– Well Pb6: 07/02/11: 4 ♀♀ (preserved material RBINSc COP 10.332); 27/07/2012: 4 ♀♀, 2♂♂ (♀ dissected RBINSc COP 10.385A-B, preserved material RBINSc COP 10.336); 26/11/12 : 2 ♀♀ (preserved material RBINSc COP 10.374); 04/03/2013: 3 ♀♀, 3♂♂, 2 juveniles (preserved material RBINSc COP 10.345); 20/09/2013: 5 ♀♀, 1 CV copepodite (preserved material RBINSc COP 10.375);

– Well Pb7: 27/7/12: 15 ♀♀, 4 ♂♂ (dissected ♀ RBINSc COP 10.325A-B, preserved material RBINSc COP 10.326); 16/04/2013: 28 ♀♀, 2 ♂♂, 1 juvenile (preserved material RBINSc COP 10.346);

– Well Pb 8: July 2013: 2 juveniles (preserved material RBINSc COP 10.343);

– Well Pb 9: 17/04/2013: 2 ♀♀ (preserved material RBINSc COP 10.341);

– Well Pb10: 27/07/2012: 2 ♀♀ (preserved material RBINSc COP 10.347); 30/09/2012: 2 ♀♀, 2 ♂♂ (preserved material RBINSc COP 10.384); 25/11/2012: 3 ♀♀ (preserved material RBINSc COP 10.383);

– Well Pb11: 27/07/2012: 68 ♀♀, 3 ♂♂ (preserved material RBINSc COP 10.344); 30/09/2012: 387 F 5 CV females; 23/02/13: 3 ♀♀, 6 CIV juvenile ♀♀, 4 CV juvenile ♀♀ (dissected adult ♀♀ RBINSc COP 10.322A-C and COP 10.323A-C, preserved material RBINSc COP 10.324);

(3) Porto-Novo, Ouémé District, Ouémé drainage basin:

– Well SA: 01/01/10: 8♀♀, 1 CIV ♀ juvenile (dissected ♀ RBINSc COP 10.318A-B, preserved material RBINSc COP 10.319); 24/10/2010: 625 adult females and males (preserved material RBINSc COP 10.382);

– Well AH: 01/11/2009: 12 ♀♀ with body covered with stalked ectoparasites (preserved material RBINSc COP 10.329 and COP 10.330); 30/03/2013: 1 ♀ (preserved material, RBINSc COP 10.380); 31/01/2014: 6 ♀♀ 2 CV juveniles (preserved material, RBINSc COP 10.381);

– Well AR: 09/12/2010: 1 ♀ (material preserved RBINSc COP 10.331); June 2013: 1 ♀, damaged (preserved RBINSc COP 10.379);

– Well LB: 20/01/2014: 83 ♀♀ 5 ♂♂ 6 copepodites (damaged, material preserved RBINSc COP 10.373); 09/03/2014: 5 ♀♀ (material preserved RBINSc COP 10.374).

(4) Kéwi, Kétou District, Ouémé drainage basin:

– village well: 08/02/11: 17 ♀♀, 1 ♂ (preserved material RBINSc COP 10.315).

Female. Body (Fig. 7A) typically cyclopid with prosome and urosome almost equally long. Prosome less prominent than in preceding species. Body length: 745 μm (730–820 μm, n=5). Laterocaudal expansion of urosomite 1 (pediger 5) accentuated by outwards directed leg 5 (Fig. 8A). Genital double-somite widest in anterior third, tapering caudally. Length/width ratio 1/1. Urosomites 4–5 parallel sided. Cephalothorax, metasomites and first urosomite with narrow and straight posterior fringe. Posterior fringe of genital double somite and urosomites 4–5 narrow and delicately serrate. Surface of somites smooth. Anal somite (Fig. 7D) with continuous row of spinules along posterior margin. Anal operculum crescent, not expanded. Anal sinus with single oblique row of minute spines on both sides.

Caudal rami (Fig. 7D) cylindrical with large mediodorsal triangular depression and 2.7 times as long as wide. Lateral anterior seta short, inserted at caudal end of median third. Distolateral element longer than ramus (ratio: 1/1.2–1.3), furnished with long slender and widely spaced spinules along outer side of stem, and widely spaced setules along medial side. Medial terminal element longer than distolateral one (ratio: 1/0.75) and ramus (ratio: 1/0.65). Breaking plane in both principal terminal setae present; each seta pinnate. Dorsal seta located in caudal third, near medial edge, articulating on short basal part and as long as medial terminal seta. Medial depression with two series of slim spinules (hairlike) arranged perpendicularly on principal axis of the rami. Posterolateral element with spinules at insertion, anterolateral one without.

Antennule 11-segmented with typical armature distribution. First segment with crescent row of slender spinules in proximal half (Fig. 4D). Aesthetasc on segment 8 as long as accompanying seta, linguiform, and reaching almost to distal margin of segment 9. Aesthetasc on segment 10 filiform, shorter than accompanying element and reaching beyond middle of terminal antennulary segment. Terminal aesthetasc as long as segments 9–11 combined, fused at base with seta. The latter longer than aesthetasc (Fig. 4C).

Antennal general aspect and armature as in A. cavicola. Frontal surface of coxobasis with defuse pattern of minute spinules in proximal half on and near outer margin (Fig. 5D). Caudal surface with 3 short rows of tiny spinules in proximal half: 1 near outer margin, 1 below a diffuse distal cluster of tiny spinules, and 1 near inner margin (Fig. 5E, F).

Mandible, maxillule and maxilliped as in A. cavicola. General aspect of maxilla as in A. cavicola. Medial claw of basis rather short and sharp, furnished with 4 large teeth increasing in length medially (Fig. 4K). Accessory element as long as claw, furnished with widely spaced spinules in proximal half, densely serrate in distal half. First endopodite segment with one smooth and one serrate element. Terminal element on second endopodite segment confluent with segment, with long widely spaced spinules in proximal half and densely serrate in distal half.

Legs 1–4 protopodite (Fig. 9A, C, F, G). Praecoxa of legs 1–3 completely devoid of ornaments, of leg 4 with a short row of spinules along distal frontal margin, near outer edge. Both sides of the coxa of legs 1–3 unadorned, except for short rows of minute spinules along the frontal distal margin. Leg 4 coxa with some spinules on the outer distal frontal edge. Caudal surface of leg 4 coxa with 2 short rows of narrow spinules near the proximal outer caudal edge, and one median row parallel with distal margin. Intercoxal sclerites smooth on both sides, with crescent unadorned laterodistal expansions in legs 1–3 (see ex. Fig. 9B). Leg 4 intercoxal sclerite (Fig. 9H) with concave distal margin, lacking laterodistal expansions. Medial coxal element present in all legs, pinnate and rather short, reaching slightly beyond the distal edge of the basis in legs 1–3, being shorter in leg 4. Medial element on leg 1 basis serrate and long, reaching to upper quarter of distal endopodite segment. Medial margin of leg 1 basis crescent and hairy. Outer seta of leg 1 basis longer than exopodite. Medial margin of legs 2–3 basis hairy, naked in leg 4. Distal inner edge of basis of legs 2–4 with short triangular expansion. Outer element on basis of leg 2 short, of legs 3–4 long.

Legs 1–4 with 2-segmented rami. Exopodite and endopodite of the legs equally long (Fig. 9A, C, F, G). Armament distribution and general aspect of segments as in preceding species. Segments devoid of ornamentation on frontal and caudal surface. Proximal endopodite segment of leg 4 flat, not expanded caudally. Leg 4 distal endopodite segment 2.2–2.3 times longer than wide with inner terminal spine slightly shorter than segmental length. Outer terminal spine half as long as inner one. Outer subdistal seta reaching to or just beyond tip of inner terminal spine, inner subdistal seta reaching far beyond tip of inner terminal spine. Proximal inner seta shorter than segment.

Leg 5 (Fig. 8A, B) confluent with pediger, represented as a single semi-circular expansion. Ancestral basal segment obsolete, represented by long pinnate seta. Ancestral distal segment represented by two equally long elements: outer one setiform, inner one spiniform.

Leg 6 (Fig. 6B) positioned laterally. Valve surface unadorned and bearing three elements on outer caudal edge: outer one setiform, median and medial one minute and truncate. Genital complex with copulatory pore leading to U-shaped duct. Lateral arms straight. Anterior receptacle expanded, with straight frontal margin. Posterior receptacle bi-lobed, expanded far caudally.

Male. Prosome and urosome equally long with metasome narrower than in the female (Fig. 7C). Urosomite 2 or pediger 6 (Fig. 8C) wide and short (W/L ratio: 2/1). Posterodorsal fringe of prosomites and posterior fringe of urosomites as in the female. Caudal rami with medial hairy ornamentation and armament as in the female. Body length: 668 μm (allotype, paratypes 665–700 μm, n=5).

Antennule as described for A. cavicola in Fiers (2012) with 3 long linguiform aesthetascs on segment 1. Antennary armament and spinule pattern, mouthparts and legs 1–4 as in the female.

Leg 5 (Fig. 8C) as in the female. Leg 6 (Fig. 7 C) represented by large semi-ovate unadorned valve. Outer caudal edge expanded, bearing two elements: outer one setiform, medial one spiniform. The former shorter than the latter.

Variability: In most cases the medial triangular depression of the caudal rami is furnished with two parallel sets of fragile hairs as shown in Fig. 7D. In some specimens an additional row is present. Apart from the ornamentation of the caudal rami a single female shows an aberrant armament of the distal endopodite of right leg 2 with only 3 medial setae instead of 4. Body length and slightly different ratios of the caudal rami and armament are noticeable. Female body lengths range from 720 μm (Well A1 population) to 835 μm (Kéwi population); males from 620 (Well A1 population) to 800 μm (Kéwi population). Length/width ratio of the caudal rami varies between 2.4 to 3.0 with the laterodistal spine 1.2–1.4 and the terminal medial seta 1.6–1.9 times longer than the rami.

Ladjifarani or “Nouveau quartier”, Parakou District, Ouémé drainage basin: Well B6 (details in Table 2).

Holotype female, dissected and mounted on 2 slides, RBINSc COP 10.334A-B, allotype male, dissected and mounted on 2 slides, RBINSc COP 10.335A-B; paratypes: dissected female RBINSc 10.367A-B, preserved material: 7 females, 3 males, 5 juveniles (RBINSc COP 10.333) all collected 29/10/2011; additional paratypic material (topotypes): 3 females collected 16/01/11 (preserved RBINSc COP 10.352).

From the Latin adjective “nudus” meaning naked and refers to the absence of hairy or spinular ornamentation on the pedigers surface and caudal rami, contrasting the species from A. spinifer sp. n. and A. pilosa sp. n.

(1) Parakou District, Ouémé drainage basin.

– Well A1: 27/08/2011: 1 ♀, 8 ♂♂ (preserved material RBINSc COP 10.337); 11/01/2011: 4 ♀♀, 1 ♂, 40 juveniles, decomposed condition (preserved material RBINSc COP 10.348); 15/02/2011: 2 ♀♀, 3 ♂♂, 20 juveniles (preserved material RBINSc COP 10.351); 10/07/2012: 48 ♀♀, 12 ♂♂ (preserved material RBINSc COP 10.338);

– Well A5: 16/11/2010: 2♂♂, 4 juveniles (preserved material RBINSc COP 10.350);

– Well C3: 30/10/2011: 1 ♂ (dissected male RBINSc COP 10.368); 14/02/2011: 27 ♀♀, 1 ♂ (preserved material RBINSc COP 10.349).

Female: Body (Fig. 10A) typically cyclopid with prosome longer than urosome (ratio: 1/0.8). Principal body flexure well marked, rather wide. Genital double-somite widest in anterior third, tapering caudally, and as long as widest part. Anal somite with crescent operculum, not expanded. Anal sinus unadorned. Length 900 μm (holotype, paratypes 890–962 μm, n=5). Posterodorsal margins of cephalothorax and pedigers 2–3 straight, of pediger 4 slightly irregular. Urosomite 1 with straight posterodorsal fringe. Posterior margin of genital double-somite and urosomites 4–5 wide, coarsely serrate. Posterior margin od anal somite with uninterrupted row of spinules along ventral and dorsal margins.

Caudal rami cylindrical with triangular depression along anterior half of medial margin, less than 3 times longer than wide (L/W-ratio 1/2.7–2.8). Anterolateral seta, pinnate, short, without spinules near articulation. Posterolateral element shorter than ramus in holotype (ratio: 0.9/1) ranging from 0.8/1–1.0/1 in paratypes), with long and slender spinules along outer side of the stem, pinnate along the inner side. Spinules present at it insertion with ramus. Medial element longer than ramus (ratio: 1.15–1.25/1) and pinnate. Principal terminal setae with breaking plane and pinnate. Dorsal seta 1.3–1.4 times longer than ramus, and articulating on small basal part. Integument of rami unadorned.

Antennule 11-segmented with typical armament, not reaching to posterolateral edge of cephalothorax. Segment 1 with set of slender spinules and set of short ones (Fig. 4 F). Aesthetasc on segment 8 linguiform, reaching beyond middle of segment 9. Aesthetasc on segment 10 filiform, shorter than accompanying seta and reaching halfway terminal segment. Aesthetasc on segment 11 tubular, as long as segments 9–11 combined, and shorter than accompanying seta (Fig. 4E).

Antenna with general appearance and armature as in A. chappuisi (see Fiers 2012). Frontal surface of coxobasis with a cluster of 7–9 small spinules near middle of outer margin and a row of slender spinules in proximal half near abexopodal margin (Fig. 5G). Caudal surface of coxobasis with 3 sets of narrow spinules in proximal half: 2 near outer margin, 1 near abexopodal margin (Fig. 5H).

Mouthparts as in preceding species. Maxillary basis (Fig. 4J) prominent and blunt, with set of 4–5 large spinules in middle, increasing in length medially. Accessorial seta robust, with large spinules on both sides of the stem in proximal half, finely serrate along one side in distal half. Armature of proximal endopodite segment and terminal armature element on distal endopodite segment robust, with large spinules in proximal half and finely serrate in distal half on one side of the stem. Terminal seta on distal endpodite segment confluent with segment. Additional elements on distal segment sparsely serrate.

Leg 1–4 protopodite (Fig. 12A–D). Frontal margin of praecoxa with short row of slender spinules near outer corner. Frontal surface of legs 1–4 coxa unadorned except for some minute spinules along distal margin. Caudal surface of leg 1 unadorned, of legs 2 and 3 with some slender spinules near outer proximal corner. Caudal surface of leg 4 coxa with a transverse row of spinules parallel to distal margin and some slender spinules near outer proximal corner. Intercoxal sclerite of legs 1–4 as in preceding species. Medial coxal seta present, pinnate and reaching beyond basis, attending distal margin of proximal endopodite segment in leg 1, and middle of proximal endopodite segment in legs 2 and 3. Medial element somewhat shorter in leg 4. Medial margin of basis of leg 1 crescent, hairy, and with pinnate element reaching beyond proximal endopodite segment. Spinules present at its insertion. Medial margin of basis of legs 2–4 crescent, produced distally in short triangular expansion. Hairy in legs 2–3, naked in leg 4. Outer seta on leg 1 basis as long as exopodite, and as long as first exopodite segment in legs 2–4.

Leg 1–4 rami 2-segmented with general appearance and armament distribution as in preceding species. Frontal and caudal surface of ramal segments unadorned. Proximal segment of leg 4 endopodite inflated caudally (Fig. 12D). Distal endopodite segment of leg 4 2.10–2.15 times longer than wide. Inner terminal spine as long as segment, and 1.8–2.1 times longer than outer spine. Medial setae on second endopodite segment equally long, not reaching beyond inner terminal spine.

Leg 5 (Fig. 11E) with ancestral segments confluent with pediger, represented as a semi-ovate expansion with a discreet truncation distally. Ancestral basal segment represented by a long setiform element. Ancestral distal segment represented by 2 elements: outer one setiform, half as long as medial spiniform element, both inserted on the distal discreet truncation.

Leg 6 (Fig. 11B) typically represented by 3 elements: outer one setiform, middle and medial ones dwarfed, hyaline and blunt. Valves unadorned. Genital complex with frontal and caudal parts of receptacles expanded. The former with undulate frontal margin, the latter with single medioventrally expansion. Copulatory pore leading to U-shaped duct (Fig. 11D). Lateral arms straight.

Male: Body narrower than female body (Fig. 10C). Prosome 1.5 times longer than urosome. Principal body flexure wide. Second urosomite (pediger 6) 2 times wider than long. Body length 795 μm (allotype, ranging from 744 to 817 in paratypes). Posterodorsal margins of prosomites and first urosomite narrow and straight. Posterior hyaline fringe margins of urosomite 2 narrow and serrate, of urosomites 3–5 wide and serrate. Anal somite with crescent, not expanded, anal operculum. Anal sinus smooth. Posterior margin of anal somite with uninterrupted row of spinules.

Caudal rami cylindrical with short triangular medial depression in anterior half. L/W-ratio: 2.7/1 (allotype, ranging from 2.7–3.0/1 in other male paratypes). Anterolateral seta short, pinnate, without spinules at insertion. Distolateral element shorter than ramus (ratio: 0.8–0.9/1) serrate along outer margin, pinnate along inner one. Spinules at insertion present. Terminal medial element longer and dorsal one longer than ramus:1.15–1.25/1 and 1.25–1.35, respectively. Dorsal seta articulating on basal part. Principal terminal setae with breaking plane and pinnate.

Antennule as described for A. cavicola in Fiers 2012. Mouthparts and legs 1–4 as in the female, except for leg 4 endopodite lacking expansion of caudal surface of the proximal segment. Leg 5 (Fig. 11C) with region representing ancestral distal segment more pronounced than in the female. Armature elements as in the female.

Leg 6 (Fig. 11C) represented as large, unadorned valve with caudally produced outer distal edge bearing 2 elements: outer one very short, setiform, medial long, spiniform and serrate.

Variability. Except for slight variation (less than 15 µm) in the body length and the L/W ratio of the caudal rami and its armament, no structural differences were observed in the type series nor in the other populations.

at Addrodji, Lokossa District, Mono Couffo drainage basin: Well P2 (details in Table 1).

Female holotype, dissected and mounted on 3 slides, RBINSc COP 10.354; allotype male, dissected and mounted on 2 slides, RBINSc COP 10.356; female paratypes dissected: RBINSc COP 10.355A-C, COP 10.357 A, COP 10. 358 A-C; 14 females and 5 males preserved (RBINSc COP 10.359), all collected 1-12-2012. Additional paratypic material (topotypic), collected 19/06/2012: 185 females, 15 males (preserved material RBINSc COP 10.360).

Named after Nestor G. Sakiti who initiated, in collaboration with Claude Boutin, subterranean biology research in Bénin, and supported the junior author initializing his investigations.

(1) Lokossa, Mono District, Mono-Couffo drainage basin:

– Well P6: 17-06-2012: 1 ♀ (preserved material RBINSc COP 10.364); 06/09/2012: 18 ♀♀ 1 ♂ (preserved material RBINSc COP 10.378); Well PM (about 20 m from well P6, cemented, closed and abandoned, and considered here as identical with well P6): 07/01/2012: 65 ♀♀, 4 ♂♂ (dissected ♀ RBINSc COP 10.370A-C; preserved material RBINSc COP 10.365).

– Well P7: 13-06-2012: 74 ♀♀, 4 ♂♂, 2 juveniles (dissected ♀ RBINSc COP 10.369A-C; preserved material RBINSc 10.363);

– Well P9: 11-06-2012: 116 ♀♀, 11 ♂♂, 9 juveniles (preserved material RBINSc COP 10.361); 30-11-2012: 9 ♀♀, 2 ♂♂ (preserved material RBINSc COP 10.362 ).

(2) Abomey-Calavi District, Ouémé drainage basin:

– Well near Campus: 27-02-2013: 24 ♀♀, 3 ♂♂, 1 juvenile (preserved material RBINSc COP 10.366).

Female: Body (Fig. 13A) typically cyclopoid with prominent prosome (1.8–1.9 times urosome length). Genital double-somite widest in anterior third, and as long as widest part. Posterodorsal fringe of prosomites and urosomite 1 narrow and straight. Posterior fringe of genital double-somite and urosomites 3–4 narrow and discretely serrate (Fig. 14A, B). Anal somite with shallow crescent operculum (Fig. 13C). Anal sinus apparently smooth. Posterior margin of anal somite with uninterrupted row of spinules: rather short dorsally, laterally and along outer half of ventral margin, twice as long along medial half of ventral margin (Fig. 14A). Body length: 833 μm (holotype, paratypes ranging from 807–876 μm, n=5).

Caudal rami (Fig. 13C) cylindrical, between 2.5 and 2.6 times longer than wide, with triangular medial depression reaching halfway the margin. Integument of caudal rami smooth. Anterolateral seta short and pinnate, without spinules at insertion. Distolateral element equally or slightly longer than ramus (ratio: 1.0–1.1/1), furnished with widely spaced setules on both sides of the stem. Spinules at insertion of distolateral element present. Terminal medial element longer than ramus (ratio: 1.3–1.5/1) and pinnate. Principal terminal setae with breaking plane and pinnate. Dorsal seta, articulating on small basal part, and as long as medial element.

Antennule 11-segmented, not reaching to posterior edge of cephalothorax. Segment 1 with crescent row of spinules in proximal half (Fig. 4H). Aesthetasc on segment 8 linguiform, as long as accompanying seta, and reaching middle of segment 9. Aesthetasc on segment 10 filiform, as long as accompanying seta, and reaching nearly to distal end of terminal segment. Aesthetasc on segment 11 tubular, as long as segments 9–11 combined, and shorter than accompanying seta (Fig. 4G).

Antennary general morphology and armature as in A. chappuisi. Frontal surface of coxobasis with a cluster of minute spinules (6–7 spinules) in middle of outer margin and a short transverse set of slender ones in the proximal half bear the abexopodal margin (Fig. 5J). Caudal surface nearly completely naked only furnished with a few slender spinules in the proximal half near the abexopodal margin. (Fig. 5I).

Mandible, maxillule, maxilliped and general aspect of maxilla as in A. cavicola and the preceding species. Claw of maxillary basis blunt, armed with 8–9 large spinules, increasing in width and length medially. Claw shorter than accessory element (Fig. 4L). The latter furnished with groups of long spinules on both sides in proximal half and along one side in distal half, besides the finely serrate ornamentation of the distal part of the stem. Both elements on proximal endopodite segment and terminal element on distal segment furnished partially with long spinules along one side of the stem, finely serrate at the opposite side. Additional setae on distal endopodite segment slender, unequal in length.

Leg 1–4 protopodite without ornamentation on praecoxa (Fig. 15A, C, E, F). Frontal surface of coxa unadorned except for the usual minute spinules along distal margin. Caudal coxal surface smooth in leg 1, with some slender and short spinules near outer proximal corner in legs 2 and 3 (Fig. 15D). Caudal surface of leg 4 coxa with 2 small clusters of spinules near outer proximal distal corner and a median row of narrow spinules parallel with distal margin (Fig. 15F). Medial coxal seta present in all legs, pinnate and reaching to middle of proximal endopodite segment in legs 1–3, but hardly beyond basis in leg 4. Intercoxal sclerites as in preceding species. Basis in leg 1 with long medial spine, reaching to middle of distal endopodite segment and with spinules at insertion. Medial margin of legs 1–3 crescent and hairy, naked in leg 4. Medial distal edge of basis in leg 1 rounded, slightly triangularly produced in legs 2–4. Outer seta on basis of legs 1 and 4 as long as exopodite, of legs 2 and 3 half as long.

Leg 1–4 rami 2-segmented with general appearance and armament distribution as in preceding species (Fig. 15A–C, E–F). Proximal segment of leg 4 endopodite slightly expanded caudally. Distal endopodite segment of leg 4 2.2–2.4 times longer than wide. Inner terminal spine shorter than segment (ratio: 0.9/1), outer spine half as long as inner one. Medial setae on distal endopodite segment of leg 4 reaching distinctly beyond longest terminal spine.

Leg 5 (Fig. 14A, B) confluent with pediger, represented as a semi-circular expansion bearing 3 elements. Ancestral basal segment represented by long setiform element, ancestral distal segment by two equally long elements: outer one setiform, inner one spiniform. Surface of leg 5 expansion with some short and hairy-like spinules.

Leg 6 (Fig. 14B) located laterally on genital double-somite, typically with 3 elements: outer one setiform, middle and medial one dwarfed, hyaline and blunt. Valve unadorned. Genital complex with small ovate anterior receptacle. Caudally expanded receptacle with single medioventral lobe. Copulatory pore leading to U-shaped duct. Lateral arms straight.

Male: General appearance of body as in the female with prosome 1.5 times longer than urosome. The latter with pediger 6 half as long as wide (Fig. 14G). Posterodorsal fringes of prosomite and first urosomite, and posterior fringes of urosomites as in the female. Body length: 676 µm (allotype and other male paratypes ranging between 650 and 695 μm; n=4).

Caudal rami 2.5–2.7 times longer than wide, distolateral element 1–1.15 times longer than caudal rami, and terminal medial element 1.30–1.45 times longer than ramus.

Antennule as described for A. cavicola in Fiers (2012). Mouthparts and legs as in the female but proximal endopodite segment of leg 4 without expansion.

Leg 5 (Fig. 14G) with general appearance and integumentary ornamentation as in the female, but with outer setiform element on distal segment vestige longer than inner spiniform element.

Leg 6 vestige (Fig. 14G) large, with protruded outer distal edge, bearing 2 elements: outer one setiform, half as long as inner one. The latter spiniform. Surface of valve unadorned.

Variability: Apart from slight variation in body length and L/W-ratio of the caudal rami and the setae on the caudal rami, no structural variability was observed.