Torrenticola harrisoni K. Viets, 1956

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Ghana, Zootaxa 3820 (1), pp. 1-80 : 13-20

Torrenticola harrisoni K. Viets, 1956

( Figs. 7A–C , 8A–F , 9A–C , 10A–E , 13A–F , 15A–F , Tabs. 1–2)

Torrenticola harrisoni K. Viets 1956: 9 .

New records. Ghana: Laboun River, downstream, Kyabobo NP, 8º 19.931 N, 0º 34.476 E, 24.ii.2013, Smit, 8/6/0 (2/ 1/0 mounted); Tagbo River, downstream of falls, 7º 00.708 N, 0º 34.326 E, alt. 394 m asl., 23.ii.2013, Smit, 2/2/0 (1/ 1/0 mounted); stream downstream of Wanjakli Falls, Likpe Todome, 7º 09.976 N, 0º 36.456 E, alt. 478 m asl., 23.ii.2013, Smit, 14/10/0 (2/0/0 mounted); Apkonu stream, downstream of falls, 6º 53.054 N, 0º 28.024 E, alt. 362 m asl., 21.ii.2013, Smit, 7/5/0 (1/0/0 mounted); small rainforest stream upstream Sagyimase, Atewa Hills, 6º 13.964 N, 0º 33.116 W, alt. 654 m asl., 08.iii.2011, Smit, 1[juvenile]/1[juvenile]/0.

Morphology. General features —Idiosoma roundish; Cxgl-4 far posterior at margin of Cx-I/II, between I-L and II-L insertions, but close to I-L insertion; excretory pore posterior to Vgl–2 ( Figs. 7A–B ); ventral margin of gnathosoma moderately curved, rostrum well developed and slender ( Fig. 8D ); P-2 shorter than P-4, P-2 ventral margin slightly S-shaped, P-2 and P-3 with a subrectangular, apically serrated distoventral projection ( Figs. 8A–C ), P-2 ventral seta very short (hardly visible), denticle-like, inserted close to distal margin of ventridistal protrusion, P-4 slender with well developed ventral protuberance in distal half of segment, bearing one long and 1–3 short setae. Male: medial suture line of Cx-II+III moderately long; 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 subrectangular in shape; ejaculatory complex with small proximal chamber; Vgl–2 close to the line of primary sclerotization, excretory pore near posterior end of idiosoma. Female: suture line of Cx-IV curved and extending further posterior to the genital field than in male; genital field pentagonal in shape; excretory pore and Vgl–2 away from the line of primary sclerotization.

Measurements. Male (from Laboun River, downstream, n = 2)—Idiosoma (ventral view: Figs. 7A , 15A–C ) L 522–541, W 375–377; dorsal shield ( Figs. 5C , 11A–C ) L 422, W 324, L/W ratio 1.3; dorsal plate L 391–392; shoulder platelets L 119–120, W 38–44, L/W ratio 2.7–3.2; frontal platelets L 106–111, W 41–44, L/W ratio 2.4–2.7; shoulder/frontal platelets L ratio 1.07–1.11. Gnathosomal bay L 74–94, Cx-I total L 191–203, Cx-I mL 109–116, Cx-II+III mL 86–103; ratio Cx-I L/Cx-II+III mL 2.0–2.2; Cx-I mL/Cx-II+III mL 1.06–1.35. Genital field L/W 110–113/90–91, ratio 1.22–1.25; ejaculatory complex L 166; distance genital field-excretory pore 86–113, genital field-caudal idiosoma margin 103–153. Gnathosoma vL 213–229; chelicera total L 252–259; palp total L 227–229, dL/H, dL/H ratio: P- 1 21–22/20 –22, 1.0–1.03; P-2 66–69/36–37, 1.83–1.86; P-3 48–52/31–32, 1.51–1.62; P-4 72–79/17, 4.36–4.73); P- 5 13–14/11, 1.25; P-2/P-4 ratio 0.84–0.95; dL of I-L-2–6: 48, 54, 69, 74–77, 74–78; I-L-6 H 29–31, dL/H I-L-6 ratio 2.4–2.7.

Plunge pool, River Tordzi, Nubui River, Ankasa River, Ankasa River, Tagbo River,

♂ ♂ ♂ ♂ ♀ ♂ Female (from Laboun River, downstream, n = 1)—Idiosoma (ventral view: Figs. 9B , 15B–C ) L 550, W 372; dorsal shield ( Fig. 13C ) L 409, W 327, L/W ratio 1.25; dorsal plate L 378; shoulder platelets L 115–116, W 44–47, L/W ratio 2.46–2.65; frontal platelets L 100–103, W 41–42, L/W ratio 2.46; shoulder/frontal platelets L ratio 1.12–1.16. Gnathosomal bay L 84, Cx-I total L 184, Cx-I mL 100, Cx-II+III mL 77; ratio Cx-I L/Cx-II+III mL 2.4; Cx-I mL/Cx-II+III mL 1.3. Genital field L/W 113/109, ratio 1.03; distance genital field-excretory pore 126, genital field-caudal idiosoma margin 172. Gnathosoma vL 219; chelicera total L 249; palp total L 227–228, dL/H, dL/H ratio: P-1, 21–22/22, 1.0; P-2, 69/35, 1.97; P-3, 49/32, 1.53; P-4, 74/17, 4.35; P-5, 14/11, 1.27; P-2/P-4 ratio 0.94; dL of I-L-3–6: 52, 65, 75, 75; I-L-6 H 29, dL/H I-L-6 ratio 2.6.

In addition to the populations listed above (here assigned as form ''A'') we give locality records and measurements of the specimens (here assigned as form ''B'') differing in the larger dimensions of idiosoma, more stout palp segments, especially P-4, with the ventral protuberance just in the distal half (compare Figs. 13A–C with 13D–F). Furthermore, these specimens differ in having a somewhat banded colour pattern rather than the solid colour pattern on the dorsal plate of the dorsal shield in specimens listed above (compare Figs. 9 F–G with 9I –M). These differences could reflect some degree of genetical diferentiation between these populations.

New records. Ghana: Agumatsa River at first bridge, Agumatsa Wildlife Sanctuary, 7º 06.830 N, 0º 35.760 E, alt. 253 m asl., 22.ii.2013, Smit, 6/3/0 (2/1/0 mounted); Plunge pool, Agumatsa Falls, Agumatsa Wildlife Sanctuary, 7º 06.350 N, 0º 36.476 E, alt. 258 m asl., 22.ii.2013, Smit, 1/0/0 (mounted); River Tordzi, 6º 32.819 N, 0º 41.445 E, alt. 79 m asl., 19.ii.2013, Smit, 1/3[one specimen damaged, palps and gnathosoma lacking]/0 (1/0/0 mounted); Nubui River, Agumatsa Wildlife Sanctuary, 7º 06.986 N, 0º 35.548 E, alt. 254 m asl., 22.ii.2013, Smit, 3/ 3/0 (1/0/0 mounted); Ankasa River, Ankasa NP, 5º 13.011 N, 2º 39.126 W, alt. 60 m asl., 13.ii.2013, Smit, 1/5/0 (1/ 1/0 mounted); Tagbo River, downstream, 7º 00.974 N, 0º 33.471 E, alt. 255 m asl, 23.ii.2013, Smit, 1/3/0 (1/0/0 mounted).

Measurements. Male (from Agumatsa River at first bridge, n = 1)—Idiosoma (ventral view: Figs. 9A , 15D ) L 569–578, W 400–403; dorsal shield ( Figs. 9C , 13D ) L 444–450, W 350–352, L/W ratio 1.26–1.29; dorsal plate L 409–411; shoulder platelets L 116–127), W 44–50), L/W ratio 2.4–2.7; frontal platelets L 122–128, W 45–50, L/W ratio 2.44–2.69; shoulder/frontal platelets L ratio 0.92–1.04. Gnathosomal bay L 91–94, Cx-I total L 200–203, Cx- I mL 109, Cx-II+III mL 94–109; ratio Cx-I L/Cx-II+III mL (1.86–2.1); Cx-I mL/Cx-II+III mL 1.0–1.16. Genital field L/W 117–123/95–97, ratio 1.23–1.27; ejaculatory complex L 162; distance genital field-excretory pore 106–119, genital field-caudal idiosoma margin 139–163. Gnathosoma vL 221–226; chelicera total L 260; palp total L 243–244, dL/H, dL/H ratio: P-1, 24–25/24–25, 1.0–1.02; P-2, 71–74/42–43, 1.64–1.75; P-3, 55/39–41, 1.36–1.44; P-4, 76–79/22, 3.4–3.65; P-5, 17–20/11–12, 1.4–1.85; P-2/P-4 ratio 0.93–0.94; dL of I-L-2–6: 51, 63, 75–77, 81–82, 83–89; I-L-6 H 32, dL/H I-L-6 ratio 2.6–2.8.

Female (from Agumatsa River at first bridge, n = 1)—Idiosoma (ventral view: Figs. 9B , 15F ) L 609, W 409; dorsal shield ( Fig. 13F ) L 481, W 350, L/W ratio 1.37; dorsal plate L 450; shoulder platelets L 122–127, W 42, L/ W ratio 2.9–3.0; frontal platelets L 116–123, W 45, L/W ratio 2.6–2.7; shoulder/frontal platelets L ratio 0.99–1.08. Gnathosomal bay L 106, Cx-I total L 209, Cx-I mL 103, Cx-II+III mL 69; ratio Cx-I L/Cx-II+III mL 3.0; Cx-I mL/ Cx-II+III mL 1.5. Genital field L/W 128/117, ratio 1.09; distance genital field-excretory pore 141, genital fieldcaudal idiosoma margin 203. Gnathosoma vL 235; chelicera total L 273; palp total L 252, dL/H, dL/H ratio: P-1, 26/25, 1.03; P-2, 81/46, 1.75; P-3, 59/42, 1.41; P-4, 67/22, 3.89; P-5, 19/12, 1.54; P-2/P-4 ratio 0.93; dL of I-L-2–6: 53, 62, 75, 81, 86; I-L-6 H 31, dL/H I-L-6 ratio 2.8.

Remarks. With respect to the general morphology of idiosoma and palp the specimens examined from Ghana agree well with Torrenticola harrisoni K. Viets, 1956 . This species was described by K. Viets (1956) based on a single male from Transvaal, South Africa. The female was described by K.O. Viets (1965) based on a juvenile specimen from Vaal River in South Africa. Later on, Motas & Tanasachi (1968) and Goldschmidt & Smit (2009) described and illustrated specimens from Ethiopia (see under Torrenticola calliope n. sp. for a discussion on these populations).

Together with Torrenticola bomiensis (see above), T. binga K.O. Viets, 1971 ( Zimbabwe, K.O. Viets 1971), and T. calliope n. sp. (see below), T. harrisoni forms a group of similar species ( Goldschmidt and Smit 2009) characterized by the V-shaped gnathosomal bay and P-2 and P-3 ventrodistally with spatula-shaped, finely serrate protrusions. The position of the Cxgl-4 far posteriorly, at the margin of Cx-I/II, between I-L and II-L insertions, is a very characteristic feature of T. harrisoni and separates later species from T. binga and T. bomiensis .

Distribution. South Africa ( K. Viets 1956, K.O. Viets 1965, 1971), Congo ( Zaire) ( K.O. Viets & Böttger 1974), Ghana (first record).

Figures

FIGURE 7 A – C. Torrenticola harrisoni K. Viets, 1956, Form '' A' ', Laboun River (A, C = male, B = female): A – B = idiosoma, ventral view; C = dorsal shield. Scale bar = 100 Μm.

FIGURE 8 A – F. Torrenticola harrisoni K. Viets, 1956, Form '' A' ', Laboun River (A – B, D – F = male, C = female): A, C = palp, medial view; B = palp, lateral view; D = gnathosoma; E = ejaculatory complex; F = I-L- 5 and - 6. Scale bars = 100 Μm.

FIGURE 9 A – C. Torrenticola harrisoni K. Viets, 1956, Form '' B' ', Agumatsa River (A, C = male, B = female): A – B = idiosoma, ventral view; C = dorsal shield. Scale bar = 100 Μm.

FIGURE 10 A – E. Torrenticola harrisoni K. Viets, 1956, Form '' B' ' (A – B, D – E = male, C = female; B = specimen from Plunge pool Agumatsa Falls, A, C – E = specimens from Agumatsa River): A, C = palp, medial view; B = palp, lateral view; D = I-L- 5 and - 6; E = gnathosoma. Scale bars = 100 Μm.

FIGURE 13 A – F. Photographs of dorsal shield of Torrenticola harrisoni K. Viets, 1956 (A – C—form '' A' ', D – F—form '' B' '): A = male from Laboun River, B = male from Tagbo River, downstream of falls, C = female from Laboun River, D = male from Agumatsa River, E = male from Plunge pool, F = female from Agumatsa River.

FIGURE 15 A – F. Photographs of ventral shield of Torrenticola harrisoni K. Viets, 1956 (A – C—form '' A' ', D – F—form '' B' '): A = male from Laboun River, B = female from Laboun River, C = female from Tagbo River, downstream of falls; D = male from Agumatsa River, E = male from River Tordzi, F = female from Agumatsa River.

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 11 A – F. Neoatractides erato n. sp., holotype male, upstream Sagyimase: A = dorsal shield (left frontal platelet missing); B = idiosoma, ventral view; C = palp, medial view; D = gnathosoma and chelicera; E = ejaculatory complex; F = I-L- 5 and - 6. Scale bars = 100 Μm.