Simocephalus (Simocephalus) mixtus Sars, 1903

Simocephalus (Simocephalus) mixtus Sars, 1903 View in CoL

Fig. 1F–J View FIGURE 1

Sars 1903b: 174; Orlova-Bienkowskaja 2001: 56–58, Figs. 85–86, Pl. I, II, VI; Rogers et al. 2019: 678, Figs. 16.2.18 I; Korovchinsky et al. 2021b: 156–157, Figs. 46, 9.

Material examined. Four juvenile parthenogenetic females from a pond at the Lake Permai, Ipoh , Perak (4.47728° N, 101.0492° E), 28.01.2018 GoogleMaps .

The species has been recorded in Peninsular Malaysia only once ( Mizuno & Mori 1970), and Idris (1983) did not include it in his monograph. Only juvenile females were present in the studied materials. Juvenile females ( Fig. 1F View FIGURE 1 ) have no distinctive protruding backward dorsal margin, characteristic for large adult females. Studied specimens have typical of subgenus S. ( Simocephalus ) morphology of head ( Fig. 1G View FIGURE 1 ) and postabdomen ( Fig. 1I View FIGURE 1 ), with outer side of postabdominal claw bearing uniform thin setulae ( Fig. 1J View FIGURE 1 ). Studied specimens have the morphology of posterior-dorsal valve prominence characteristic of the species ( Fig. 1H View FIGURE 1 ). The species was recently found in Sabah State, East Malaysia ( Sinev & Yusoff 2018). In South-East Asia, S. mixtus was recorded in the North-East Thailand ( Maiphae et al. 2008) and in Hainan Island (Sinev et al. 2015). For detailed description, see Orlova-Bienkowskaja (2001). Two other species of S. ( Simocephalus ), S. (S.) vetulus (O. F. Muller, 1776) and S. (S.) vetuloides Sars, 1898 were also recorded in South-East Asia ( Korovchinsky 2013), but no morphological descriptions were provided for them. According to Orlova-Bienkowskaja (2001), these species are distributed in temperate regions only, so their presence in the region is doubtful.