Mixaderus, Collado & Alonso-Zarazaga, 1996

Gompel, Nicolas, 2021, New Mixaderus species from the Mascarene Islands (Coleoptera: Aderidae), Zootaxa 4969 (1), pp. 166-174 : 173-174

Updated key to Mixaderus species from the Mascarene Islands

For illustration of the characters referred to in this key, see previous synopsis in Gompel (2012).

1. Elytra uniformly coloured, legs entirely pale................................................................ 2

- Elytra bicolour: brown or black, with a pattern of pale stripes and spots.......................................... 6

2. Head, thorax and abdomen entirely black.................................................................. 3

- Head, thorax and abdomen entirely pale................................................................... 4

3. Elytra mat, species from Madagascar.............................................................. M. perrieri

- Elytra shiny, species from La Réunion.............................................................. M. voisini

4. Thorax transverse............................................................................... M. snelli

- Thorax as long as wide......................................................................... M. simplex

6. Antennae thick, densely pubescent and entirely dark......................................................... 7

- Antennae thinner, yellow to partially dark.................................................................. 9

7. Antennomeres 4‒10 transverse........................................................................... 8

- Antennomeres 4‒10 as long or longer than wide. Length <2mm ................................. M. angustefasciatus

8. Pattern of white pubescence extending to the posterior fifth of the elytra. Length> 2mm ................ M. ptinomorphus

- Pattern of white pubescence excluded from the posterior third of the elytra. Length <2mm ............... M. reunionensis

9. Elytra brown with an alternating pattern of whitish and dark bands................................... M. mauritiensis

- Elytra with a different coloration........................................................................ 10

10. Elytra dark with a single transverse yellow stripe, located in their anterior half.................................... 11

- Elytra pigmentation more complex, involving at least two pale, transverse and sinuate stripes, or multiple patches........ 12

11. Elytral stripe broad, reaching the humeral region laterally........................................... M. basithorax

- Elytral stripe narrower, remote from the humeral region........................................ M. cinereofasciatus

12. Anterior elytral stripe strongly sinuate.................................................................... 13

- Anterior elytral stripe broad, with weak or no sinuation, sometimes reduced to discrete blotches, or pattern more complex. 16

13. Thorax transverse.................................................................................... 14

- Thorax as long as wide...................................................................... M. poussereaui

14. Anterior elytral stripe extends anteriorly and posteriorly along suture.................................. M. mantillerii

- Anterior stripe not extended along suture................................................................. 15

15. Posterior stripe with a deep, loop-shaped sinuation............................................. M. sinuatefasciatus

- Posterior stripe with milder sinuation............................................................. M. emmerezi

16. Apex of elytra with a broad, distinct band of pale pigmentation (whitish or yellow)................................ 17

- Apex of elytra dark, at most with a very narrow stripe of pale pigmentation, but then pronotum pale, contrasting with the overall darker elytra........................................................................................ 18

17. Elytra with three simple transversal yellow stripes. Base of pronotum only marked with withe pubescence.... M. madecassus

- Elytra with a complex pattern of white pubescence, not limited to simple stripes. Pronotum entirely covered with whitish pubescence................................................................................... M. tamisieri

18. Pronotum pale, contrasting sharply with the dark head and elytra....................................... M. chassaini

- Background color of the pronotum similar to the background color of the head and elytra, with at most a pattern of pale pubescence.............................................................................................. 19

19. Yellow humeral spot barely visible. Elytra less than 3.5 longer than pronotum.................................... 20

- Yellow humeral spot distinct. Elytra 3.5 totimes longer than pronotum.................................. M. superbus

19. Antennae at least partially dark, male foretarsae with first tarsomere slightly wider than next ones............... M. gomyi

- Antennae entirely yellow, male foretarsae with first tarsomere twice as wide as the following............... M. lemagneni