Allocyclops pilosus, 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 : 6-11

Taxon classification Animalia Cyclopoida Cyclopidae

Allocyclops pilosus sp. n. Figs 4C, D, K, 5 D–F, 7, 8, 9

Syn. Allocyclops sp. [partim] in Lagnika et al. 2014b

Type locality.

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

Type material.

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).

Etymology.

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

Additional material.

(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).

Description.

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 Allocyclops 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 Allocyclops cavicola . General aspect of maxilla as in Allocyclops 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 min ute 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 Allocyclops 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.