APPENDIX 1.
Key to extinct species of Trichodesma (modified from Zahradník and Háva, 2017).
| (1) | Elytra without tufts of erect setae. Body length 4.8 mm | Trichodesma amberica |
| - Elytra with tufts of erect setae | 2 | |
| (2) | Each elytron with 8 tufts of black, erect setae (Figure 2.2). Body length 6.9 mm | Trichodesma electra |
| - Each elytron with less than 8 tufts of erect setae | 3 | |
| (3) | Each elytron with 5 tufts of black, erect setae (Figure 2.1). Body length 4.2 mm | Trichodesma groehni |
| - Each elytron with 6 tufts of reddish-brown, erect setae (Figure 2.3). Body length 6.2 mm | Trichodesma fennosarmatica sp. nov. |
