Sandracottus mixtus ( Blanchard, 1843 )

Alarie, Yves, Michat, Mariano C., Shaverdo, Helena & Hájek, Jiří, 2023, Morphology of the larvae of Sandracottus femoralis Heller, 1934, and S. mixtus (Blanchard, 1843) and phylogenetic comparison with other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae), Zootaxa 5263 (3), pp. 301-334 : 306

Sandracottus mixtus ( Blanchard, 1843)

( Figs 31–39 )

Source of material. The larvae (19 instar I, seven instar II, 13 instar III) were collected from three sampling sites (cf., notes below) near the following locality: Myanmar, Shan State: Mintaingbin Forest Camp, ca. 1290 m; 20˚55.640′N, 96˚33.634′E; 14/15/17/19/20/22. VI.2004, leg. H. Shaverdo. The identification is firm as S. mixtus represents the only species of the genus Sandracottus and the tribe Aciliini known from Myanmar.

Diagnosis. Larvae of S. mixtus can be distinguished from those of S. femoralis , the only other Sandracottus species described in detail, by the following combination of characters: antennomere 1 subequal to slightly longer than antennomere 3 (instar I) ( Table 1 ); antennomeres 1–2 sparsely covered with spinulae ( Fig. 33 ); anterior process of prementum longer relative to length of labial palpomere 1 ( Tables 1 , 3 , 5); pro- and mesofemur with more than 28 and 33 anteroventral additional natatory setae, respectively (instar I) ( Table 2 ).

Figures

FIGURES 31–32. Sandracottus mixtus (Blanchard, 1843), lateral habitus: (31) instar I; (32) instar II. Photo by H. Schillhammer.

FIGURES 33–34. Sandracottus mixtus (Blanchard, 1843), instar I: (33) antenna, dorsal aspect; (34) labium, dorsal aspect.AN, antenna; LB, labium. Numbers and lowercase letters refer to primary setae and pores, respectively. Scale bars = 0.1 mm.

FIGURES 35–36. Sandracottus mixtus (Blanchard, 1843), instar III: (35) dorsal habitus; (36) lateral habitus. Photo by H. Schillhammer.

FIGURES 37–39. Habitat of Sandracottus mixtus (Blanchard, 1853) near Mintaingbin Forest Camp, Shan State, Myanmar; (37) roadside puddles on a muddy limestone bed with decomposing leaves; (38) open and partly shaded pond on clay bed with fine limestone gravel and decomposing leaves; (39) shallow open pools on a white clay bed covered with vegetation. Photos by H. Shaverdo.