Sathytes Westwood 1870

Sathytes Westwood, 1870

Chinese common name: ḛà甲¤

Sathytes Westwood, 1870: 128; Löbl 1979 (revision of world species); Yin et al. 2012a (redescription); Yin & Shen 2020 (checklist of world species). Type species: Sathytes punctiger Westwood, 1870: 128 (monotypy).

= Batoxylina Jeannel, 1957: 8. Type species: Batoxylina clavalis Jeannel, 1957: 9 (original designation). Synonymized by Löbl 1979: 285.

This is a rather easily recognizable genus with all included members possessing a coarsely punctate dorsal surface of the body, and a great number of foveae at the elytral bases and the bases of the abdominal segments. The males of all species, except S. simplex Löbl, possess strongly modified and enlarged antennal clubs of characteristic forms, thus making identifications less difficult in most cases with enough careful comparisons. In Tibet, it is common to find several species at the same location, making it sometimes impossible to associate females with males of species that have a similar body size with 100% assurance. Sathytes is diverse in China, and seven species have been previously reported from Tibet (Yin et al. 2012a; Shen & Yin 2020; Yin & Shen 2020), with another 12 species being described here. Additionally, Sathytes simplex is newly reported to occur in Tibet.

The 20 Tibetan species are keyed below. It should be kept in mind that in some cases a direct and careful comparison between the specimens is the only means for separating morphologically similar species due to often different angles showing the antennal modifications in published literatures.

Key to Tibetan species of Sathytes (male)

1 Antenna simple, lacking modifications (Fig. 58C)............................................... S. simplex Löbl

- Antenna with antennomeres 9 and 11 modified (Figs 49–57, 59–61)............................................. 2

2 Antennomere 11 markedly elongate, ratio (length/width) greater than 1.85 (Figs 49C, 60C; Yin & Shen 2020: fig. 3B)..... 3

- Antennomere 11 weakly to moderately elongate, ratio (length/width) less than 1.80................................. 5

3 Body length less than 2.7 mm (2.64 mm); ratio (length/width) of antennomere 11 less than 1.9 (1.89) (Fig. 60C); aedeagus expanded apically and with broadly emarginate apical margin (Fig. 60F).......................... S. virupaksa sp. nov.

- Body length 2.8 mm or more; ratio (length/width) of antennomere 11 greater than 2.0; aedeagus apically as broad as basal half................................................................................................ 4

4 Setae of head relatively much longer and sparser (Fig. 49A); pronotum more elongate, ratio (length/width) 80/71 (Fig. 49A, B); distributed in Cona..................................................................... S. aequalis sp. nov.

- Setae of head relatively much shorter and denser (Yin & Shen 2020: fig. 3A); pronotum less elongate, ratio (length/width) 80/78 (Yin & Shen 2020: fig. 3A); distributed in Zayü.......................................... S. chayuensis Yin & Shen

5 Antennomere 11 with two basal protuberances (Yin & Shen 2020: fig. 6B, D).................. S. linzhiensis Yin & Shen

- Antennomere 11 with single basal protuberance............................................................. 6

6 Hyaline apophysis located on apical 1/2 of antennomere 9 (Figs 55D, 56D, 61D; Yin & Shen 2020: figs 10C, 13C)........ 7

- Hyaline apophysis located at middle or on basal 1/2 of antennomere 9 (e.g., D in Figs 50–54, 57, 59).................. 11

7 Body length less than 2.0 mm (1.94–1.95 mm); antennomere 10 of unique form (Fig. 55D).......... S. pengzhongi sp. nov.

- Body length greater than 2.0 mm; antennomere 10 not formed as above.......................................... 8

8 Body length greater than 2.5 mm (2.61–2.72 mm); antennomere 9 strongly expanded mesally (Yin & Shen 2020: fig. 13C); basal protuberance of antennomere 11 conspicuously extended posteriorly to reach antennomere 10 (Yin & Shen 2020: fig. 13B)............................................................................ S. transversus Yin & Shen

- Body length less than 2.3 mm; antennomere 9 moderately expanded mesally or obliquely expanded at anteromesal portion; basal protuberance of antennomere 11 not short and not reach antennomere 10… 9

9 Anterior margin of antennomere 9 distinctly oblique (Fig. 56D); antennomere 11 with relatively shorter basal protuberance, apical margin subtruncate (Fig. 56C)....................................................... S. proclivis sp. nov.

- Anterior margin of antennomere 9 even; antennomere 11 with relatively longer basal protuberance and angulate apical margin .................................................................................................. 10

10 Antennomere 11 relatively longer, ratio (length/width) 1.72 (Fig. 61C); hyaline apophysis of antennomere 9 more anteriorly positioned (Fig. 61D)................................................................. S. yigongensis sp. nov.

- Antennomere 11 relatively shorter, ratio (length/width) 1.6 (Yin & Shen 2020: fig. 10B); hyaline apophysis of antennomere 9 more posteriorly positioned (Yin & Shen 2020: fig. 10C)................................. S. panzhaohuii Yin & Shen

11 Body length greater than 3.0 mm........................................................................ 12

- Body length less than 3.0 mm.......................................................................... 14

12 Antennomere 9 strongly inclined at mesal margin (Yin et al. 2012a: fig. 7F); aedeagus (Yin et al. 2012a: fig. 8F)............................................................................................... S. magnus Yin & Li

- Antennomere 9 oblique, but not as inclined as above; aedeagus of a different form................................. 13

13 Body length approximately 3.5 mm; tempus relatively longer, length of eye/tempus 0.78 (Fig. 51B); aedeagus at middle weakly narrowed (Fig. 51F)................................................................. S. caichenyangi sp. nov.

- Body length approximately 3.1 mm; tempus relatively shorter, length of eye/tempus 0.81 (Fig. 53B); aedeagus at middle strongly narrowed (Fig. 53F)................................................................ S. duojii sp. nov.

14 Body length 2.1 mm or slightly less (Fig. 54A).............................................. S. laticornis sp. nov.

- Body length greater than 2.3 mm ........................................................................ 15

15 Antennomere 9 relatively more elongate (Fig. 52D), ratio (length/width) 1.18–1.23.................... S. dawai sp. nov.

- Antennomere 9 relatively less elongate, ratio (length/width) less than 1.05....................................... 16

16 Hyaline apophysis located at approximately middle of antennomere 9 (Yin & Shen 2020: fig. 16C).................................................................................................... S. xizangensis Yin & Shen

- Hyaline apophysis located on basal 1/2 of antennomere 9..................................................... 17

17 Aedeagus broadened apically (Fig. 57F)............................................... S. pseudograndis sp. nov.

- Apical part of aedeagus as broad as basal half.............................................................. 18

18 Hyaline apophysis of antennomere 9 relatively longer (Fig. 59D); basal protuberance of antennomere 11 relatively short (Fig. 59C).............................................................................. S. sympatricus sp. nov.

- Hyaline apophysis of antennomere 9 relatively shorter; basal protuberance of antennomere 11 relatively long........... 19

19 Body smaller in size (length 2.7 mm or slightly more), antenna shorter (1.39–1.43 mm), antennomeres 9 slightly more elongate (Fig. 50D) and antennomere 11 stouter (Fig. 50C), apical margin of aedeagus not expanded on left side (Fig. 50F)................................................................................................ S. asura sp. nov.

- Body larger in size (length 2.9 mm or slightly more), antenna longer (1.51 mm), antennomeres 9 slightly stouter (Yin & Shen 2020: fig. 1C) and antennomere 11 more elongate (Yin & Shen 2020: fig. 1B), apical margin of aedeagus expanded on left side (Yin & Shen 2020: fig. 1E)............................................................. S. alpicola Yin & Shen