Second contribution to the knowledge of water mites from the Comoros, with the description of one new species (Acari: Hydrachnidia) Author Smit, Harry Author Pesic, Vladimir Author Mary-Sasal, Nathalie text Zootaxa 2010 2413 51 60 journal article 10.5281/zenodo.194335 0832d1cc-89b1-46ea-b018-7c0876d6109e 1175-5326 194335 Monatractides ventriosus (K. Viets, 1916) Material examined . Comoros , Mayotte : Koual River, downstream, 12°48'19,5"S 45°09'49,7"E , 08-x-2008 , 1/2/0 (1/1/0 mounted); Koual River, legion, 12°47'49,7"S 45°11'08,6"E , 08-x-2008 , 17/23/1 (1/1/0 mounted); River Chirini, downstream, 12°46'39,7"S 45°06'16,4" E , 08-x-2008 , 82/2; River Comboni, 12°46'17,2"S 45°08'51,1"E , 07-x-2008 2/3/0; River Botirini, 12°45'37,7" S 45°06'42,6" E , 05-x-2008 , 52/4 (1/0/0 mounted); Mro oua Goulou (Goulou River), 12°47'27,2"S 45°11'22,9"E , 7-x-2008 , 81/2 (1/1/0 mounted); River Ourouveni, downstream (Old Bridge), 12°48'29,9"S 45°07'39,4"E , 2-x-2008 , 1/0/0; River Bouyouni, downstream, 12°44'25,3"S 45°08'33,3"E , 5-x-2008 , 12/12/0; River Djalimov, downstream, 12°47'14,4"S 45°06'51,7"E , 3-x-2008 , 1juvenile /0/0. Remarks. As already pointed out by Cook (1966) , Monatractides ventriosus is an extremely variable species or, more likely, a series of very closely related species which are presently being confused. The specimens from Comoros agree well with the measurements for specimens from South Africa given by K.O.Viets (1965) . In addition we give the measurements based on the specimens from Koual River. Male . Idiosoma L 750, W 669; dorsal shield L 663, W 506, L/W ratio 1.3; dorsal plate 594; frontal plate L 128, W 88, L/W ratio 1.46; shoulder plate L 202, W 84, L/W ratio 2.4; capitular bay L 140, its lateral margin with three pairs of knob-shaped protrusions; Cx-1 total L 272, Cx-1 medial L 131, Cx-2+3 medial 82; ratio Cx-1 L/Cx-2+3 medial L 3.3; Cx-1 medial L/Cx-2+3 medial L 1.6; genital field L/W 141/120, L/W ratio 1.2; ejaculatory complex L 197; distance genital field–excretory pore 148, genital field–caudal idiosoma margin 244; capitulum ventral L 158; chelicera L 225; palp total L 214, dL and %L (in parentheses): P-1, 28 (13.1); P-2, 58 (27.1); P-3, 39 (18.2); P-4, 57 (26.6); P-5, 32 (15.0); L P-2/P-4 ratio, 1.02. Female . Idiosoma L 813, W 725; dorsal shield L 681, W 556, L/W ratio 1.23; dorsal plate 613; frontal plate L 125, W 91, L/W ratio 1.37; shoulder plate L 209, W 84, L/W ratio 2.5; capitular bay L 144, lateral margin as in males; Cx-1 total L 283, Cx-1 medial L 138, Cx-2+3 medial 55; ratio Cx-1 L/Cx-2+3 medial L 5.2; Cx-1 medial L/Cx-2+3 medial L 2.5; genital field L/W 170/157, L/W ratio 1.08; distance genital field– excretory pore 169, genital field–caudal idiosoma margin 297; capitulum ventral L 163; chelicera L 210; palp total L 218, dL and %L (in parentheses): P-1, 22 (10.1); P-2, 61 (28.0); P-3, 42 (19.3); P-4, 61 (28.0); P-5, 32 (14.7); L P-2/P-4 ratio, 1.0. Distribution . West Africa ( Cameroon , Liberia ), East Africa ( Kenya ), Central Africa ( Congo ), South Africa , Comoros . The variability of populations from different regions of the whole distribution area needs to be examined to clarify the taxonomy (Smit et al. 2009).