Djeboa davecooki Pešić & Smit, 2018

Pešić, Vladimir, Smit, Harry & Mary, Nathalie, 2018, Fifth contribution to the knowledge of water mites (Acari: Hydrachnidia) from the Comoros: a checklist and description of one new genus and four new species, Zootaxa 4483 (2), pp. 331-348 : 345

Djeboa davecooki Pešić & Smit sp. nov.

( Figs. 9–10 , 11E–F )

Type series: Holotype male ( MNHN), dissected and slide mounted, Comoros, Mayotte, Dembéni River, upstream, 12°51'38,7"S, 43°09'30,8"E, alt. 156 m asl., 18-vii-2015, leg. Mary. Paratypes: same data as holotype, 31-vii-2014 1/0/0 ( RMNH); Hajangoua stream, 12°52'1,0"S, 45°10'25,7"E, alt. 265 m asl., 18-vii-2015 0/1/0 (dissected and slide mounted, RMNH); River Djalimou, upstream, 12°56'58,4"S, 45°07'23,7"E, alt. 165 m asl., 16-vii-2014 1/0/0 ( MNHN).

Diagnosis: Lateral ridges of central depression not extending to frontal and caudal margin of dorsal shield; gnathosomal bay Y-shaped, in posterior part widened; P-4 L/H 3.1, ventral margin almost straight; I-L-6 L/H 2.8- 2.9.

Description. General features —Dorsal shield oval (L/W ratio 1.15–1.16), with medial depression; muscle scars anterior and posterior to the postocularia, with moderately pronounced thickenings, second pair located well within the concavity ( Figs. 9A , 11E ); gnathosomal bay Y-shaped, in posterior part widened ( Fig. 11F ); tips of Cx-I extending to frontal margin; median margin of Cx-IV comparatively well developed. Palp: P-1 with a dorsal seta; P-2 with straight ventral and convex dorsal margin; P-3 ventral margin with a basal kink, distally straight; P-4 relatively slender, ventral margin almost straight ( Figs. 9D , 10B ). Legs: I-L ( Fig. 9E ) with I-L-6 L/H ratio 2.8–2.9, ventral margin distally convex; IV-L: Fig. 10C ; swimming setae numbers: III-L-4, 4; III-L-5, 4; IV-L-4, 2; IV-L-5, 4.

Measurements: Male (holotype)—Idiosoma (ventral view: Fig. 9B ) L/W 463/442. Dorsal shield ( Figs. 9A ) L/ W 392/340, ratio 1.15; gnathosomal bay L 91; distance between IV-L insertions 288. Gonopore long and narrow, L 69; ejaculatory complex L 109. Palp: total L, dL/H, dL/H ratio: P-1, 23/22, 1.04; P-2, 52/40, 1.29; P-3, 52/23, 2.21; P-4, 64/20, 3.14; P-5, 17/10, 1.69; P-2/P-4 ratio 0.81. Legs: dL of I-L: 38, 46, 45, 53, 72, 89; I-L-6 H 31, I-L-6 L/H ratio 2.85; dL of IV-L-4-6: 86, 92, 81.

Female (paratype)—Idiosoma (ventral view: Fig. 10A ) L/W 463/428. Dorsal shield L/W 406/350, ratio 1.16; gnathosomal bay L 91; distance between IV-L insertions 275. Gonopore L/W 81/72. Palp: total L, dL/H, dL/H ratio: P-1, 22/22, 1.0; P-2, 53/42, 1.26; P-3, 53/25, 2.1; P-4, 63/20, 3.1; P-5, 16/10, 1.64; P-2/P-4 ratio 0.85. Legs: dL of I-L: 42, 47, 45, 52, 69, 83; I-L-6 H 30, I-L-6 L/H ratio 2.8; dL of IV-L: 66, 66, 64, 80, 105, 118.

Etymology: The new species is named after David Cook (Paradise Valley) in appreciation of his studies of water mites.

Discussion: The combination of an Y-shaped gnathosomal bay, a relatively long and slender P-3 of nearly same height along the entire length (except for the proximoventral bulge), and the large dorsal shield concavity with the lateral ridges not extending to frontal and caudal margin, makes the new species most similar to D. granatica Cook, Pešić & Gerecke, 2013 from Madagascar ( Pešić et al. 2013) and D. dinosaurophila Pešić, Cook & Gerecke, 2013 from South Africa ( Pešić et al. 2013). Djeboa granatica , known only from a male, can be distinguished from the new species by a comparatively slender P-4, with a concave ventral margin (see fig. 24E in Pešić et al. 2013) and Cx-III/IV with longitudinal striation. Djeboa dinosaurophila differs in having a gnathosomal bay comparatively narrower proximally, a proportionally thicker distal segment of I-L and in the dorsal shield medial depression rounded in its posterior half ( Pešić et al. 2013).

Distribution: Comoros; known only from the loci typici.

Figures

FIGURE 9. Djeboa davecooki sp. nov., male, Dembéni River, Mayotte: A = dorsal shield; B = ventral; C = ejaculatory complex; D = palp; E = I-L. Scale bars = 100 µm.

FIGURE 10. Djeboa davecooki sp. nov., female, Dembéni River, Mayotte: A = ventral; B = palp; C = IV-L. Scale bars = 100 µm.

FIGURES 11. Photographs of dorsal (A, C–E) and ventral (B, F): A–B Platymamersopsis mayottensis sp. nov., male holotype. C–D Torrenticola mayottensis sp. nov.: C = male holotype, F = female paratype. E–F Djeboa davecooki sp. nov., male holotype.