Monatractides stigeophora ( Cook, 1966 )

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Ghana, Zootaxa 3820 (1), pp. 1-80 : 35-36

Monatractides stigeophora ( Cook, 1966)

( Figs. 22A–G , 25F–G , 26F–G )

Torrenticola (Monatractides) stigeophora Cook 1966: 86

New records. Ghana: Supon stream near Asiakwa, Atewa Hills, 6º 15.530 N, 0º 30.642 W, alt. 250 m asl., 7.iii.2011, Smit, 0/1/0 (mounted); Small rainforest stream upstream Sagyimase, Atewa Hills, 6º 13.964 N, 0º 33.116 W, alt. 654 m asl., 8.iii.2011, Smit, 0/1[juvenile]/0 (mounted); Apkonu stream, downstream of falls, Logba Tata, 6º 53.054 N, 0º 28.024 E, alt. 362 m asl., 21.ii.2013, Smit, 0/1/0.

Morphology. Female. General features —Idiosoma elongated oval; frontal platelets shorter than shoulder platelets (shoulder/frontal platelets L ratio 1.2–1.4); frontal margin medially convexly rounded, between anterolaterally pointed apodemes ( Fig. 22C ); Cx-I with rounded tips, Cxgl–4 located far distal, nearly at tips of Cx- I; gnathosomal bay deep, U-shaped; genital field pentagonal; suture line of Cx-IV distinct, originating from lateral edge of genital field and extending far beyond posterior margin of the genital field ( Fig. 22B ); excretory pore and Vgl-2 posterior to the line of primary sclerotization, Vgl-2 slightly posterior to excretory pore; gnathosoma with protruding rostrum, pointed in lateral view ( Fig. 22G ); chelicera with a long, needle-like claw; palps compact and stout, P-4 ventral margin almost straight without ventral setae ( Figs. 22D–E ); I-L with I-L-6 L/H ratio 1.9, basally narrowed, distally thickened ( Fig. 22F ).

Measurements (from Supon stream, in parentheses juvenile specimen [indicated by weak sclerotization and caudal position of excretory pore, see Figs. 25G , 26G ] from stream upstream Sagyimase)—Idiosoma (ventral view: Figs. 22B , 26F ) L 738 (595), W 463 (418); dorsal shield ( Figs. 22A , 25F ) L 628 (541), W 395 (372), L/W ratio 1.59 (1.45); dorsal plate L 594 (506); shoulder platelets L 150 (168–172), W 56 (50), L/W ratio 2.7 (3.4); frontal platelets L 119–122 (125), W 48–50 (47–50), L/W ratio 2.44–2.45 (2.5–2.66); shoulder/frontal plate L ratio 1.23–1.26 (1.34–1.38). Gnathosomal bay L 153 (167), Cx-I total L 272 (272), Cx-I mL 119 (105), Cx-II+III mL 46 (51); ratio Cx-I L/Cx-II+III mL 5.9 (5.3); Cx-I mL/Cx-II+III mL 2.6 (2.1). Genital field L/W 164 (155)/141 (136), ratio 1.16 (1.14); distance genital field-excretory pore 184, genital field-caudal idiosoma margin 256. Gnathosoma vL 192; chelicera total L 260 (262), basal segment L 155–160 (166), claw L 103–105 (99); palp total L 195–198 (199), dL/H, dL/H ratio: P-1, 28/28, 1.0 (29/32, 0.91); P-2, 61–62/51, 1.2 (66/49, 1.34); P-3, 38–39/43, 0.89 (37/41, 0.9); P-4, 47/31, 1.53 (46/29, 1.58); P-5, 21–22/15, 1.5 (21/15, 1.34); P-2/P-4 ratio 1.31 (1.43); dL of I-L: 51, 60, 66 (65), 77 (77), 83 (80), 92 (89); I-L-6 H 48 (46), dL/H I-L-6 ratio 1.93 (1.93).

Remarks. The specimens from Ghana agree well in general morphology with Monatractides stigeophora ( Cook, 1966) , a species described by Cook (1966) based on a single female from a stream in Liberia. Within the genus, Monatractides (M.) stigeophora ( Cook, 1966) ( Liberia) , M. (M.) neostigeophora ( Cook, 1966) ( Liberia, Cook 1966), and M. (M.) falcifera ( K.O. Viets, 1974) ( Congo, K.O. Viets & Böttger 1974) form a group of similar species, the “ stigeophora species group“. This group is characterized by a pointed, protruding gnathosomal rostrum and chelicera with a long, needle-like claw.

Distribution. Liberia ( Cook 1966), Ghana (first record).

Figures

FIGURE 22 A – G. Monatractides stigeophora (Cook, 1966), female (A – B, D – G = from Supon stream, C = from Apkonu stream): A = dorsal shield; B = idiosoma, ventral view; C = frontal margin of idiosoma, dorsal view; D = palp, medial view; E = palp, lateral view; F = I-L- 5 and - 6; G = gnathosoma and chelicera. Scale bars = 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.