Atractides (Atractides) ghanaensis, Pešić, Vladimir & Smit, Harry, 2015

Pešić, Vladimir & Smit, Harry, 2015, Water mites of the genus Atractides Koch, 1837 (Acari: Hydrachnidia: Hygrobatidae) from Ghana, Zootaxa 3911 (3), pp. 343-356 : 344-348

Atractides (Atractides) ghanaensis n. sp.

( Figs. 2A–E , 3A–E )

Type series. Holotype male ( RMNH), dissected and slide mounted, small rainforest stream upstream Sagyimase, Atewa Hills, 6º 13.964 N, 0º 33.116 W, alt. 654 m asl., 8.iii.2011, Smit. Paratypes ( RMNH): one female, same data as holotype, dissected and slide mounted; two males, unnamed creek upstream Sagyimase, Atewa Hills, 6º 13.966 N, 0º 33.114 W, alt. 671 m asl., 28.ii.2013, Smit, one male dissected and slide mounted.

Diagnosis. Dorsal muscle insertions sclerotized, forming an unpaired plate in males, two paired and one unpaired plate(s) in females; Cx-IV with extended border of secondary sclerotization including Vgl-3; excretory pore smooth; Vgl-1: fused to Vgl-2; palp with weak sexual dimorphism, ventral margins P-2–3 slightly concave; S- 1 and -2 distanced, S-1 long and slender, S-2 distinctly shorter, I-L-6 slender.

Description. Integument finely striated; muscle insertions sclerotized: sexual dimorphism in the dorsal area. Coxal field: posteromedian margin Cx-I+II rounded, Cx-IV with extended caudal and lateral margins of secondary sclerotization completely including Vgl-3 ( Fig. 2B ). Excretory pore smooth; Vgl-1: fused to Vgl-2. Palp: with weak sexual dimorphism, ventral margin of P-2 and P-3 weakly concave, P-4 sword seta near to, or distally from, distoventral seta ( Figs. 2C , 3C ). Legs: I-L-5 strongly thickened, with ventral and dorsal margins diverging from base to S-1 insertion, in the extended area between S-1 and -2 subparallel, S-1 and -2 heteromorphic and distanced, S-1 long, slightly bent inwards and with rounded tip, S-2 shortened, thicker than S-1, tip bluntly pointed; I-L-6 long and slender, only slightly narrowed from the base to the tip ( Figs. 2D–E , 3D ); claws with ventral and dorsal clawlets ( Fig. 3E ). Male: extended dorsal shield with irregular undulating margins including prefr, postoc, Dgl-3–6, and D-1–5 (further Lgl–3 can be fused to the lateral margin of the shield, Fig. 2A ), other glandularia on extended platelets. Genital field: anterior margin with extended and convexly protruding secondary sclerotization, posterior margin medially indented; P-4 sword seta distal to distoventral seta. Female: Arrangement of dorsal muscle insertions and glandularia as illustrated in Fig. 3B : postoc + D-1 + Dgl-3 fused, Dgl-4 + D-3 fused, asymmetrically fused with, or separate from, unpaired posterior shield including Dgl-5/-6 and D-4/-5.

Measurements. Male (holotype, in parentheses specimen from unnamed creek upstream Sagyimase)—Idiosoma length/width 475 (454)/394 (375); dorsal shield length/width 331 (334)/253 (259); coxal field: length 341 (334); Cx-III width 281 (269); Cx-I+II medial length 115 (115), lateral length 181 (183); genital field length/width 134 (129)/131 (123), length Ac 1–3: 25–27 (22–24), 24 (22), 22–27 (19–21).

Palp: Total length 207, dorsal length/height, dorsal length/height ratio: P-1, 20/17, 1.2 (22/17, 1.25); P-2, 43/ 27, 1.57 (41/26, 1.59); P-3, 49/24, 2.03 (48/24, 1.96); P-4, 66/16, 4.1 (62/15, 4.1); P-5, 29/9, 3.4 (29/8, 3.8); length P-2/P-4 ratio 0.65 (0.65). Capitulum ventral length 78 (79); chelicera total length 122 (127).

Legs: I-L-5 dorsal length 141 (140), ventral length 82 (79), dorsal length/ventral length ratio 1.72 (1.78), maximum height 52 (55), dorsal length/maximum height 2.7 (2.53), S-1 length 101 (101), length/width ratio 8.2 (7.3), S-2 length 62 (68), length/width ratio 4.0 (4.4), distance S-1-2, 34 (34), length ratio S-1/2, 1.64 (1.49); I-L-6 length 118 (125), central height 14 (15), length/central height ratio 8.4 (8.5); length I-L-5/6 ratio 1.19 (1.12).

Female—Idiosoma length/width 566/447, coxal field: length 363; Cx-III width 307; Cx-I+II medial length 114, lateral length 184; genital field length/width 146/156, pregenital sclerite width 111, genital plates length/ width 95-97/50-54, length Ac 1–3: 26–32, 25–29, 24; egg (n = 2) maximum diameter 119–122.

Palp: Total length 208, dorsal length/height, dorsal length/height ratio: P-1, 23/17, 1.33; P-2, 42/27, 1.57; P-3, 51/23, 2.2; P-4, 63/15, 4.3; P-5, 29/9, 3.1; length P-2/P-4 ratio 0.67.

Legs: I-L-5 dorsal length 146, ventral length 81, dorsal length/ventral length ratio 1.8, maximum height 58, dorsal length/maximum height 2.53, S-1 length 114, length/width ratio 8.2, S-2 length 72, length/width ratio 4.9, distance S-1-2, 41, length ratio S-1/2, 1.58; I-L-6 length 134, central height 14, length/central height ratio 9.6; length I-L-5/6 ratio 1.09.

Etymology. Named after the country where the new species was found.

Remarks. Atractides splendidus (Lundblad, 1927) , a species known from East Africa ( Lundblad 1927a, b) closely resembles A. ghanaensis n. sp. due to extended sclerotization of dorsal muscle insertions, in mature specimens forming one extended shield in males, two paired and one unpaired plate(s) in females, and the similar shape of palp and I-L-5 and - 6 in both sexes. It can be distinguished from the new species in the more extended ventral sclerotization, in the male including the coxae, genital field and Vgl-3–4, and in both sexes an extended excretory pore sclerite. Furthermore, A. splendidus differs in distinctly larger dimensions (idiosoma length 552 in male, 700 in female, palp total length 298 in male, 373 in female, I-L-5/6 length 157/ 150 in male, 200/ 214 in female; data taken from Lundblad 1927b), and more slender setae S-1 and S-2.

Distribution. Ghana.

Figures

FIGURE 2 A – E. Atractides ghanaensis n. sp., male (A, C, E = holotype, B, D = paratype), small rainforest stream upstream Sagyimase: A = idiosoma, dorsal view; B = idiosoma, ventral view; C = palp, medial view; D – E = I-L- 5 and - 6. Scale bars = 100 Μm.

FIGURE 3 A – E. Atractides ghanaensis n. sp., paratype female, small rainforest stream upstream Sagyimase: A = idiosoma, ventral view; B = idiosoma, dorsal view; C = palp, lateral view; D = I-L- 5 and - 6; E = IV-L claw. Scale bars = 100 Μm.