Stenomastigus, Leleup, 1968

Jałoszyński, Paweł, 2025, Two new species of the South African genus Stenomastigus Leleup (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5590 (1), pp. 101-112 : 110-111

Species and subspecies of Stenomastigus can be identified using the key given below (males only).

The systematics of this genus is still unclear, and the status of some subspecies requires further study. Populations of Stenomastigus inhabit strongly fragmented habitats separated by areas transformed by humans, and specimens from such separated populations within some species differ. This problem was solved by Leleup (1968) by establishing many subspecies (not only in Stenomastigus , but also in Palaeostigus Newton ). Some of them differ mainly in external features (e.g., pigmentation), and some show strong differences in the shape of the aedeagus. It seems that all subspecies of S. longicornis Leleup may be in future elevated to species rank, S. varii saxatilis Leleup and S. varii fontinalis Leleup are candidates for synonymization and seem to represent one species separate from S. varii varii Leleup , and S. varii riparius Leleup also may be a separate species. Moreover, S. holmi Franz requires redescription, because the aedeagus was illustrated only in the lateral view, and the original description is too fragmentary.

1 Protibia with subtriangular tooth with sharp-angled apex.......................................... S. kochi Leleup

- Protibia lacking subtriangular tooth with sharp-angled apex.................................................... 2

2 Distoventral region of protrochanter forming elongate projection at least as long as proximal (articulating) region of trochanter........................................................................................... 3

- If distoventral region of protrochanter is developed as elongate projection, it is much shorter than proximal region of trochanter........................................................................................... 5

3 Elytra dark brown; protrochanteral projection gradually narrowing distally; capsular region of aedeagus delimited distally by constriction as narrow as ~1/3 of its width............................................... S. kosianus Jałoszyński

- Elytra light umbra brown; protrochanteral projection indistinctly broadening distally; capsular region of aedeagus delimited distally by constriction wider than half of its width........................................................... 4

4 Protibia widest proximad subapical emargination; paramere in lateral view with conspicuously long lateral subtriangular process opposite endophallus........................................................... S. basilewskyi Leleup

- Protibia widest distad subapical emargination; paramere in lateral view with vestigial lateral rounded process opposite endophallus............................................................................. S. allaeri Leleup

5 Protrochanter nearly quadrate; paramere in lateral view distad apex of copulatory piece as long as or longer than remaining region of aedeagus; and basal capsule delimited by constriction much broader than its half width or not delimited......... 6

- Protrochanter clearly elongate; paramere distad apex of copulatory piece shorter than remaining region of aedeagus, if longer, then basal capsule delimited by constriction narrower than its half width.......................................... 9

6 Parameral apex in lateral view bifurcate................................................................... 7

- Parameral apex in lateral view not bifurcate................................................................ 8

7 Paramere distad apex of endophallus much longer than remaining region of aedeagus, in lateral view largely straight, bent toward abparameral side only in subapical region..................................... S. longicornis bicolor Leleup

- Paramere distad apex of endophallus as long as remaining region of aedeagus, in lateral view bent twice, in submedian and subapical regions...................................................... S. longicornis umkomaasiensis Leleup

8 Paramere in abparameral view bent in subapical region......................... S. longicornis longicornis (Boheman)

- Paramere in abparameral view straight............................................. S. longicornis errans Leleup

9 Distoventral region of protrochanter forming pointed subtriangular projection............. S. berlinafricanus Jałoszyński

- Distoventral region of protrochanter not subtriangular....................................................... 10

10 Basal capsule in abparameral view distinctly narrower than remaining region of aedeagus........................... 11

- Basal capsule in abparameral view broader than or subequal in width to remaining region of aedeagus................. 12

11 Elytra nearly black; basal capsule in abparameral view much narrower than remaining region of aedeagus.................................................................................................... S. vulgaris (Lhoste)

- Elytra dark umbra brown; basal capsule in abparameral view as wide as remaining region of aedeagus............................................................................................. S. mpumalanganus Jałoszyński

12 Basal capsule in abparameral view distinctly broader than remaining region of aedeagus............................ 13

- Basal capsule in abparameral view subequal in width to remaining region of aedeagus.............................. 14

13 Elytra nearly black; paramere in abparameral view nearly straight and conspicuously slender....... S. dendrophilus Leleup

- Elytra light umbra brown; paramere in abparameral view recurved and conspicuously stout............ S. jeanneli Leleup

14 Aedeagus (together with paramere) more than 10 times as long as wide.............................. S. moori Leleup

- Aedeagus (together with paramere) at most 9 times as long as wide............................................. 15

15 Distal region of aedeagus (together with paramere) shorter than basal capsule.................................... 16

- Distal region of aedeagus (together with paramere) longer than basal capsule..................................... 17

16 In lateral view paramere strongly broadened in subapical region............................. S. pilicornis (Boheman)

- In lateral view paramere not broadened......................................................... S. holmi Franz

17 Elytra black.............................................................................. S. franzi Leleup

- Elytra light or dark umbra brown........................................................................ 18

18 Distal region of aedeagus (together with paramere) only slightly longer than basal capsule........... S. inopinatus Leleup

- Distal region of aedeagus (together with paramere) several times longer than basal capsule.......................... 19

19 In abparameral view distal region of paramere subtriangular, gradually narrowing towards apex, only ~3 times as long as wide and much shorter than copulatory piece...................................................... S. joannae Leleup

- In abparameral view distal region of paramere rod-like, over 5 times as long as wide and as long as or longer than copulatory piece.............................................................................................. 20

20 In lateral view, apex of paramere broadened, spatulate....................................................... 21

- In lateral view, apex of paramere not broadened............................................................ 22

21 Head pitch brown or black, pronotum pitch brown......................................... S. varii saxatilis Leleup

- Head dark reddish, pronotum light reddish brown........................................ S. varii fontinalis Leleup

22 Pronotum black.................................................................... S. bulirschi Jałoszyński

- Pronotum reddish brown.............................................................................. 23

23 In abparameral view basal capsule more than twice as long as wide; basal and distal regions of paramere confluent, not delimited by rapid narrowing...................................................... S. pseudofranzi Jałoszynski

- In abparameral view basal capsule at most twice as long as wide; distal region of paramere delimited from basal region by rapid narrowing.......................................................................................... 24

24 In abparameral and lateral views paramere distinctly recurved, with lateral margins sinuate............ S. varii varii Leleup

- In abparameral and lateral views paramere weakly curved, with lateral margins not sinuate......... S. varii riparius Leleup