Monatractides convexiscutata ( K. Viets, 1958 )

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Ghana, Zootaxa 3820 (1), pp. 1-80 : 30-32

Monatractides convexiscutata ( K. Viets, 1958)

( Figs. 18A–E , 19A–E , 25B–C , 26B–C , 44A )

Torrenticola (Torrenticola) convexiscutata K. Viets 1958: 102 .

New records. Ghana: stream Asukuma, Kakum NP, 5º 26.995 N, 1º 25.071 W, alt. 131 m asl., 12.ii.2013 Smit 1/2[1 juvenile]/0 (1/1/0 mounted).

Morphology. General features —Idiosoma roundish; shoulder platelet elongated (shoulder/frontal platelets L ratio 1.7–1.9); frontal margin medially with large anterolaterally pointed apodemes ( Figs. 18D–E ); Cxgl-4 located far anteriorly, near tips of Cx-I; gnathosomal bay V-shaped; suture line of Cx-IV distinct, originating from lateral edge of genital field; line of primary sclerotization close to posterior margin of genital field; excretory pore and Vgl-2 well separated from the line of primary sclerotization, Vgl-2 posterior to excretory pore; gnathosoma elongated in lateral view, rostrum truncated ( Fig. 19E ); P-2 shorter than P-4, ventral and dorsal setae of P-2 and P- 3 relatively strong and long, P-2 and P-3 distal margins without pointed tips; P-4 swollen in distal half, with two ventral setae, one of which is very long and away from distal edge ( Figs. 19A–B ). Male: medial margin of Cx-II/III relatively short; genital field small and rounded, ejaculatory complex with small proximal chamber, carina anterior long ( Figs. 19D , 44A ). Female: genital field large and rounded.

Measurements. Male—Idiosoma (ventral view: Figs. 18A , 26B ) L 483, W 378; dorsal shield ( Figs. 18B , 25A ) L 426, W 332, L/W ratio 1.28; dorsal plate L 391; shoulder platelets L 153, W 54, L/W ratio 2.8; frontal platelets L 88, W 62–63, L/W ratio 1.4; shoulder/frontal platelets L ratio 1.74. Gnathosomal bay L 86, Cx-I total L 197, Cx-I mL 112, Cx-II+III mL 70; ratio Cx-I L/Cx-II+III mL 2.8; Cx-I mL/Cx-II+III mL 1.6. Genital field L/W 97/94, ratio 1.03; ejaculatory complex L 150; distance genital field-excretory pore 91, genital field-caudal idiosoma margin 114. Gnathosoma vL 85; chelicera total L 109; palp total L 154, dL/H, dL/H ratio: P-1, 17/17, 1.0; P-2, 39/28–29, 1.35; P-3, 30/23, 1.3; P-4, 43/14 [maximum 20], 3.1 [2.1]; P-5, 25/8, 3.2; P-2/P-4 ratio 0.89; dL of I-L-2–6: 43, 52, 55, 54, 62–62; I-L-6 H 26, dL/H I-L-6 ratio 2.35.

Female—Idiosoma (ventral view: Figs. 18C , 26C ) L 547, W 413; dorsal shield ( Fig. 25C ) L 453, W 362, L/W ratio 1.25; dorsal plate L 422; shoulder platelets L 145–148, W 50–52, L/W ratio 2.88–2.91; frontal platelets L 78–81, W 53, L/W ratio 1.47–1.53; shoulder/frontal platelets L ratio 1.8–1.9. Gnathosomal bay L 78, Cx-I total L 184, Cx-I mL 106, Cx-II+III mL 65; ratio Cx-I L/Cx-II+III mL 2.8; Cx-I mL/Cx-II+III mL 1.6. Genital field L/W 117/122, ratio 0.96; distance genital field-excretory pore 134, genital field-caudal idiosoma margin 148. Gnathosoma vL 99; chelicera total L 119; palp total L 155, dL/H, dL/H ratio: P-1, 19/18–19, 1.0; P-2, 39/28, 1.4; P-3, 31/21–22, 1.43; P-4, 43/14, 3.1; P-5, 23/7, 3.2; P-2/P-4 ratio 0.91; dL of I-L-2–6: 41, 53, 58, 57, 64; I-L-6 H 25, dL/H I-L-6 ratio 2.61.

Remarks. The specimens from stream Asukuma agree well in general morphology with Monatractides convexiscutata ( K. Viets, 1958) , a species originally described from Cameroon ( K. Viets 1958), and later on reported by Cook (1966) from Liberia.

Distribution. West Africa: Cameroon ( K. Viets 1958), Liberia ( Cook 1966), Ghana (new record).

Figures

FIGURE 18 A – E. Monatractides convexiscutata (K. Viets, 1958), stream Asukuma (A – B, D = male, C, E = female): A, C = idiosoma, ventral view; B = dorsal shield; D – E = frontal margin of idiosoma, dorsal view. Scale bar = 100 Μm.

FIGURE 19 A – E. Monatractides convexiscutata (K. Viets, 1958), stream Asukuma (A – B, D = male, C, E = female): A = palp, lateral view; B = palp, medial view (P- 1 lacking); C = I-L- 5 and - 6; D = ejaculatory complex; E = gnathosoma. Scale bar = 100 Μm.

FIGURE 25 A – I. Photographs of dorsal shield. A Monatractides acutiscutatus (K. Viets, 1914), female, unnamed creek upstream Sagyimase. B – C M. convexiscutata (K. Viets, 1958), stream Asukuma: B = male, C = female. D – E M. koenikei (K. Viets, 1916): D = male from Nubui River, E = female from Akaa Falls. F – G M. stigeophora (Cook, 1966), female: F = specimen from Supon stream, G = juvenile specimen from stream upstream Sagyimase. H – I M. cf. ventriosus (K. Viets, 1916): H = male from Laboun River, I = female from Agumatsa River.

FIGURE 26 A – I. Photographs of ventral shield. A Monatractides acutiscutatus (K. Viets, 1914), female, unnamed creek upstream Sagyimase. B – C M. convexiscutata (K. Viets, 1958), stream Asukuma: B = male, C = female. D – E M. koenikei (K. Viets, 1916): D = male from Nubui River, E = female from Akaa Falls. F – G M. stigeophora (Cook, 1966), female: F = specimen from Supon stream, G = juvenile specimen from stream upstream Sagyimase. H – I M. cf. ventriosus (K. Viets, 1916): H = male from Laboun River, I = female from Agumatsa River.

FIGURE 44 A – L. Photographs of ejaculatory complex: A Monatractides convexiscutata (K. Viets, 1958), male, Asukuma River. B M. melpomene n. sp., Amedzofe Falls. C M. euterpe n. sp., creek upstream Sagyimase. D M. cf. ventriosus (K. Viets, 1916), male, Laboun River. E – L Monatractides microstoma - species complex (E – G—Form '' A' ', H – L—Form '' B' '; E – H—ejaculatory complex reduced to sclerotized framework above the genital field, I – L ejaculatory complex slide-mounted): E, L = specimens from Tagbo River, F, H – K = specimens from Apkonu stream, G = specimen from Plunge pool Agumatsa Falls.