Allocyclops spinifer, 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 : 3-6

Taxon classification Animalia Cyclopoida Cyclopidae

Allocyclops spinifer sp. n. Figs 2, 3, 4A, B, I, 5 A–C, 6

Type locality.

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

Type material.

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.

Etymology.

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.

Additional material.

(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).

Description.

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

Variability.

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 Allocyclops spinifer sp. n. as described above.