Monatractides oxystomus (K. Viets, 1935 )

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72: 48-49

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Monatractides oxystomus (K. Viets, 1935 )


Monatractides oxystomus (K. Viets, 1935)  

( Figs. 28E View FIGURE 28 , 29E View FIGURE 29 , 30B View FIGURE 30 , Tab. 4 View TABLE 4 )

Atractides oxystomus K. Viets 1935: 571   .

Material examined. Malaysia, Borneo , Kipungit River , Poring Hot Springs , Mt Kinabalu, 6º02.776 N, 116º41.432 E, 568 m asl., 15.ix.2012 Smit 1/0/0 (mounted); Kibamabangan River, at waterfall, GoogleMaps   Crocker Range, 5º51.280 N, 116º08.417 E, 433 m asl., 18.ix.2012 Smit 0/1/0 GoogleMaps   .

Compared material

Monatractides oxystomus (K. Viets, 1935)   : Lectotype ♀, here designated, SMF 4361 View Materials Torrenticola oxystoma   ♀, type, K.Viets 47777, Java, Tjibodas, 1400 m, Kali Tjiwalen, 13.7.1929   . Paralectotype ♀, on the same slide, here designated.

Monatractides tobaensis (K. Viets, 1935)   : Lectotype ♂, here designated, SMF 4509 View Materials Torrenticola tobaensis   ♂, type, K.Viets 47804, Sumatra, Toba-Meer, 5 m, 8.4.1929   . Paralectotype ♀, on the same slide, here designated.


Male. General features —Idiosoma elongated-oval; shoulder platelet elongated (shoulder/frontal plate L ratio 2.0); frontal margin medially with large anterolaterally pointed apodemes; Cxgl–4 located far anteriorly, near tips of Cx-I; gnathosomal bay V-shaped, three pairs of knob-like protrusions at the lateral margins of gnathosomal bay; medial margin of Cx-II/III moderately long; genital field subrectangular; ejaculatory complex: proximal and distal arms well developed, carina anterior long, proximal chamber small ( Fig. 30B View FIGURE 30 ); suture line of Cx-IV distinct, originating from lateral edge of genital field, laterally curved; 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 with long dorsal apodemes, rostrum truncated; distal margin of P-3 and P4 medially and laterally with several pointed extensions; P-4 with two ventral setae, one very long and away from distal edge.

Remarks. The male specimen from Kipungit River agrees well in general morphology with Monatractides oxystomus (K. Viets, 1935)   , a species originally described from Sumatra (K. Viets 1935) based on two females. The male was described by Lundblad (1971) from Central Java.

Monatractides oxystomus   seems to be most similar to M. tobaensis (K. Viets, 1935)   , a species decribed from Toba Lake, in N Sumatra from at depth of 5 m (K. Viets 1935). The main difference between M. macroporus   and M. tobaensis   concerns the gnathosomal bay, characteristically V-shaped in the both species: in M. oxystomus   three pairs of knob-like protrusions laying at the lateral margins of gnathosomal bay, while they are lacking in M. tobaensis   . However there is one another important difference between these two species—the presence of swimming setae on the legs II–IV in M. tobaensis   . The presence of swimming setae on legs was mentioned by K.Viets in the original description of M. tobaensis   and its confirmed by our re-examination of the holotype of M. tobaensis   . The numbers of swimming setae are as follows: II-L-4, 1; II-L-5, 1; III-L-4, 1; III-L-5, 1; IV-L-4, 1; IVL-5, 1. This is the second species of the genus characterized by the presence of swimming setae on legs. Recently, Pešić & Smit (2014) erected a new subgenus, Vietsclio   , to accommodate Monatractides uniscutatus (K. Viets, 1925)   , a species known from Cameroon (K. Viets 1925) and Ghana ( Pešić & Smit 2014). The latter species can easily be distinguished from M. tobaensis   due to the anterolateral platelets fused with the large dorsal plate forming an undivided dorsal shield. Therefore we propose to shift M. tobaensis   to the subgenus Vietsclio Pešić & Smit, 2014   .

Distribution. Sumatra (“ Atractides oxystomus ” K. Viets 1935   ), Java (“ Torrenticola oxystoma ” Lundblad 1971   ), Thailand ( Pešić & Smit 2009b). New for Borneo.














Monatractides oxystomus (K. Viets, 1935 )

Pešić, Vladimir & Smit, Harry 2014

Atractides oxystomus K. Viets 1935: 571

Viets, K. 1935: 571