Allocyclops sakitii, Fiers, Frank & Lagnika, Moissou, 2015

Fiers, Frank & Lagnika, Moissou, 2015, Four new representatives of the genus Allocyclops Kiefer, 1932 from semi-consolidated subsoil aquifers in Benin (Copepoda, Cyclopoida, Cyclopidae), Subterranean Biology 16, pp. 1-36 : 13-20

Taxon classification Animalia Cyclopoida Cyclopidae

Allocyclops sakitii sp. n. Figs 4G, H, L, 5I, J, 13, 14, 15

Type locality.

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

Type material.

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).

Etymology.

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.

Additional material.

(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).

Description.

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 Allocyclops 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 Allocyclops 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. 15 A–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 Allocyclops 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.