Monatractides

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 67-68

Key to the Monatractides species from Borneo

1 Gnathosoma cylindrical, elongated posterior to palp insertion, rostrum long and bent ventrally; P-5 almost reduced but clawlike setae of this segment lengthened and down-turned, partially hidden by the heavy setae at the distal margin of P-4....................................................................................... M. plumosa Wiles, 1987

- Gnathosoma laterally compressed, not elongated posterior to palp insertions, rostrum short; P-5 not reduced, claw-like setae normal in shape....................................................................................... 2

2 Frontal and shoulder platelets fused with dorsal plate forming an undivided dorsal shield............... M. phobetor n. sp

- Frontal and shoulder platelets not fused with dorsal plate...................................................... 3

3 Gnathosomal bay V-shaped, posteriorly equally narowed...................................................... 4

- Gnathosomal bay U-shaped, in posterior part with subparalel margins or slightly widened............................ 5

4 Gnathosomal bay with three pairs of knob-like protrusions at lateral margins, distal margin of P-3 and P-4 with several pointed extensions, ventral seta on P-4 long and away from distal edge........................... M. oxystomus (K. Viets, 1935)

- Gnathosomal bay without knob-like protrusions at lateral margins, distal margin of P-3 and P-4 straight, P-4 ventral setae short, not reaching the tip of P-5........................................................... M. phantasos n. sp.

5 Shoulder platelets much longer than frontal platelets (L/W ratio> 2.0,> 50 % length of dorsal plate)................................................................................................. M. circularis (K. Viets, 1935)

- Shoulder platelets shorter (L/W ratio <1.5, <50 % length of dorsal plate)......................................... 6

6 Gnathosomal bay narrow (L/W ratio> 3.0), Cx-I anteriorly slender and long....................................... 7

- Gnathosomal bay relatively wide (ratio L/W <3.0), Cx-I anteriorly broad and short................................ 10

7 Large in size (Idiosoma L> 1300 µm); posterior suture line of Cx-IV medially approaching and parallel to each other, distal margins of P-2 and P-3 with pointed extensions, ventral seta on P-4 thickened....................... M. heracles n. sp.

- Smaller in size (Idiosoma L <1000); posterior suture line of Cx-IV medially not parallel to each other; distal margins of P-2 and P-3 without pointed extensions, ventral seta on P-4 slender................................................. 8

8 Idiosoma slender (L/W ratio 1.7–1.8), suture line of Cx-IV lightly accentuated............ M. longiventris (K. Viets, 1939)

- Idiosoma broader (L/W ratio 1.4–1.5), posterior suture line of Cx-IV distinct...................................... 9

9 Ejaculatory complex normal with small proximal chamber, proximal and distal arms well developed, carina anterior long............................................................................... M. macroporus (K. Viets, 1935)

- Ejaculatory complex with large proximal chamber, proximal and distal arms short, carina anterior short.... M. epiales n. sp.

10 Frontal platelets distinctly longer than shoulder platelets (L/W ratio 0.7–0.8).............. M. parviventris (K. Viets, 1935)

- Frontal platelets shorter than shoulder platelets (L/W ratio> 1.0)............................................... 11

11 Large in size (Idiosoma L 800–1000 µm); posterior suture line of Cx-IV distinct, ventral setae on P-2 and P-3 slender; P-4 more slender.......................................................................... M. morpheus n. sp.

- Smaller in size (Idiosoma L <600 µm); posterior suture line of Cx-IV nearly obliterated; ventral setae on P-2 and P-3 thickened; P-4 stouter.................................................................. M. minuta n. sp. (female)