Torrenticola fasciata ( K. Viets, 1916 )

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Ghana, Zootaxa 3820 (1), pp. 1-80 : 10

Torrenticola fasciata ( K. Viets, 1916)

( Figs. 5A–E , 12E–F , 14E–F )

Atractides damkoehleri fasciata K. Viets 1916: 267 .

New records. Ghana: unnamed creek crossing road to Ankasa NP, 5º 11.435 N, 2º 39.429 W, alt. 20 m asl, 27.ii.2011, Smit, 19/0 (1/1/0 mounted); Ankasa River, Ankasa NP, 5º 13.011 N, 2º 39.126 W, alt. 60 m asl., 13.ii.2013, Smit, 0/1/0; Supon stream near Asiakwa, Atewa Hills, 6º 15.530 N, 0º 30.642 W, 7.iii.2011, Smit, 1/1/0.

Morphology. General features —Idiosoma roundish; shoulder platelets fused to the large dorsal plate; dorsal shield with colour pattern as illustrated in Figs. 12E–F ; gnathosomal bay U-shaped, proximally pointed; Cxgl-4 far posterior at margin of Cx-I/II near insertion of II-L; Vgl-2 on the margin of primary sclerotization, excretory pore posterior to Vgl-2 ( Fig. 5B ); gnathosoma with curved ventral margin; P-2 nearly equal in length as P-4, P-2 ventral margin straight, P-2 ventrodistal protrusion, bluntly pointed and cone-shaped, curved towards distal; P-3 ventrodistal protrusion pointed and cone-shaped; P-4 with well developed ventral protuberances, ending in two tips separated by a concavity ( Figs. 5D–E ). Male: medial suture line of Cx-II+III moderately long; posterior suture line of Cx-IV distinct, medially starting from posterior margin of genital field in a right angle to the main idiosoma axis; genital field large and subrectangular in shape; ejaculatory complex conventional in shape (with well developed anterior keel and proximal arms—Fig. 5C); postgenital area short. Female: posterior suture line of Cx-IV curved and extending more posterior from the genital field than in male, genital field pentagonal in shape.

Measurements. Male (from unnamed creek crossing road to Ankasa NP, n = 1)—Idiosoma (ventral view: Figs. 5B , 14E ) L 559, W 442; dorsal shield ( Fig. 5A , 12E ) L 453, W 359, L/W ratio 1.26; dorsal plate L 427; frontal platelets L 103, W 50, L/W ratio 2.1. Gnathosomal bay L 125, Cx-I total L 225, Cx-I mL 100, Cx-II+III mL 102; ratio Cx-I L/Cx-II+III mL 2.2; Cx-I mL/Cx-II+III mL 0.98. Genital field L/W 142/119, ratio 1.2; ejaculatory complex L 213; distance genital field-excretory pore 78, genital field-caudal idiosoma margin 88. Gnathosoma vL 252; chelicera total L 323; palp total L 289–291, dL/H, dL/H ratio: P-1, 34–35/35–36, 0.97; P-2, 89/49, 1.8; P-3, 58–59/46, 1.27; P-4, 88/32, 2.7; P-5, 20/14, 1.43; P-2/P-4 ratio 1.02; dL of I-L-4–6: 86, 94, 92; I-L-6 H 31, dL/H I- L-6 ratio 3.0.

Female (from unnamed creek crossing road to Ankasa NP, n = 1)—Idiosoma (ventral view: Fig. 14F ) L 634, W 475; dorsal shield ( Fig. 12F ) L 510, W 397, L/W ratio 1.28; dorsal plate L 477; frontal platelets L 117–119, W 50–52, L/W ratio 2.3. Gnathosomal bay L 141, Cx-I total L 241, Cx-I mL 100, Cx-II+III mL 69; ratio Cx-I L/Cx- II+III mL 3.5; Cx-I mL/Cx-II+III mL 1.5. Genital field L/W 150/144, ratio 1.04; distance genital field-excretory pore 147, genital field-caudal idiosoma margin 152. Gnathosoma vL 295; chelicera total L 375; palp total L 318–320, dL/H, dL/H ratio: P-1, 41–42/41–42, 1.0; P-2, 97/57, 1.7; P-3, 61–62/50, 1.23; P-4, 99/34, 2.9; P-5, 20/ 15, 1.3; P-2/P-4 ratio 0.98; dL of I-L-4–6: 94, 102, 97; I-L-6 H 32, dL/H I-L-6 ratio 3.0.

Remarks. Torrenticola fasciata belonged to the former subgenus Rusetria , characterized by the fusion of the shoulder platelets with the large dorsal plate. This group includes six rather similar African species: T. fasciata , T. ima K.O. Viets, 1974 , T. obtusidens Lundblad, 1951 , T. procera K.O. Viets, 1965 , T. proxima Lundblad, 1951 , and T. solitaria K.O. Viets, 1974 . The combination of the characteristic colour pattern on the dorsal shield ( Figs. 12E–F ) and Cxgl–4 far posterior, at the margin between Cx-I and Cx-II, separates T. fasciata from all other members of this group.

Distribution. Cameroon ( K. Viets 1916), Liberia ( Cook 1966), Kenya ( Lundblad 1952).

Figures

FIGURE 5 A – E. Torrenticola fasciata (K. Viets, 1916), unnamed creek crossing road to Ankasa NP (A – D = male, E = female): A = dorsal shield; B = idiosoma, ventral view; C = ejaculatory complex; D = palp, medial view; E = palp, lateral view. Scale bars = 100 Μm.

FIGURE 12 A – I. Photographs of dorsal shield: A – B Torrenticola anomallela Cook, 1966: A = male from Akaa Falls, B = female from Apkonu stream. C – D Torrenticola bomiensis Cook, 1966: C = male from Supon stream, D = female from Tagbo river. E – F Torrenticola fasciata (K. Viets, 1916), unnamed creek crossing road to Ankasa NP: E—male, F—female. G – H Torrenticola motasi Cook, 1966: G = female from tributary of Oguntwe, H = male from stream downstream of Wanjakli Falls. I Neoatractides erato n. sp., holotype male, upstream Sagyimase.

FIGURE 14 A – I. Photographs of ventral shield: A – B Torrenticola anomallela Cook, 1966: A = male from Akaa Falls, B = female from Apkonu stream. C – D Torrenticola bomiensis Cook, 1966: C = male from Supon stream, D = female from Tagbo river. E – F Torrenticola fasciata (K. Viets, 1916), unnamed creek crossing road to Ankasa NP: E = male, F = female. G – H Torrenticola motasi Cook, 1966: G = male from stream downstream of Wanjakli River, H = female from tributary of Oguntwe. I Neoatractides erato n. sp., holotype male, upstream Sagyimase.