Torrenticola

Smit, Harry, Pesic, Vladimir & Mary-Sasal, Nathalie, 2010, Second contribution to the knowledge of water mites from the Comoros, with the description of one new species (Acari: Hydrachnidia), Zootaxa 2413, pp. 51-60 : 52-54

Torrenticola sp.

( Figs. 2A–D )

Material examined. Comoros, Mayotte: Mro oua Dembeni (Dembeni River), downstream, 6-x-2008, 0/1/0 (0/1/0 mounted).

Morphology. Female. Idiosoma (ventral view: Fig. 2B ) L 725, W 533; dorsal shield ( Fig. 2A ) L 594, W 430, L/W ratio 1.38; dorsal plate 563; frontal plate L 128, W 52, L/W ratio 2.5; shoulder plate L 164, W 59, L/ W ratio 2.8; Cxgl-4 apical; capitular bay L 176, Cx-1 total L 322, Cx-1 medial L 145, Cx-2+3 medial 27; ratio Cx-1 L/Cx-2+3 medial L 11.9; Cx-1 medial L/Cx-2+3 medial L 5.5; genital field L/W 153/150, L/W ratio 1.02; distance genital field–excretory pore 147, genital field–caudal idiosoma margin 216; capitulum ( Fig. 2D ) proximally higher, ventral margin strongly curved, rostrum mid-sized, proximally high, ventral L 347; chelicera L 411; palp ( Fig. 2C ) total L 305, L and %L (in parentheses): P-1, 34 (11.2); P-2, 109 (35.7); P-3, 63 (20.7); P-4, 82 (26.9); P-5, 17 (5.6); L P-2/P-4 ratio, 1.33; P-2 longer than P-4; ventrodistal protrusion at P-2 and P-3 slender spatula-shaped, distally finely serrate; long seta laterally at base of P-2 and P-3 protrusions; P- 4 relatively short, setae-bearing projection on ventral margin broad bifurcate.

Remarks. The species described here belongs to the group of similar species comprising T. binga K. O. Viets , T. bomiensis Cook , T. harrisoni K. Viets , and T. spatulifera Goldschmidt & Smit which most likely represent a sister-group of the T. serratipalpis -group (see: Goldschmidt & Smit 2009 for diagnostic characters). Due to the similar shape of the palp (relatively long seta laterally at base of P-2 protrusions, P-4 relatively short, setae-bearing projection on ventral margin broad bifurcate) and capitulum (proximally higher, ventral margin strongly curved, rostrum mid-sized, proximally high) the female specimen from Comoros is most similar to T. spatulifera from South Africa ( Goldschmidt & Smit 2009). However, the female specimen from the Comoros differs from the female of T. spatulifera in having a shorter medial margin of Cx-2+3, a longer P-2 and a shorter ventrodistal projection at P-2 and P-3. It is worth to note that Goldschmidt & Smit (2009) found one female different from the other mounted females of T. spatulifera in the aforementioned characters. Further important differences in our specimen are the apical Cxgl-4 (in T. spatulifera Cxgl-4 located between tips of Cx-1, and insertion of leg-I), a longer P-2 ventral seta and excretory pore fused with the area of primary sclerotization (in T. spatulifera excretory pore posterior to caudal margin of primary sclerotization) in the female specimen from the Comoros.

Most probably our specimen represents a species new to science. However, since additional material (including male specimens) is not available, the introduction of a new name will create more confusion than information given the present state of knowledge.

Figures

FIGURE 2 A – D. Torrenticola sp., female, Dembeni River: A = dorsal shield; B = idiosoma, ventral view; C = palp, medial view; D = capitulum. Scale bars = 100 μm.