Diplotrichus, Jordal, 2021

Jordal, Bjarte H., 2021, An integrated taxonomic revision of Diplotrichus (Coleoptera, Scolytinae) supports a Malagasy origin and single colonisation of South Africa, Zootaxa 5047 (2), pp. 101-122 : 103-104

Key to the species of Diplotrichus

1 South African species; interstrial setae rather long in most species, separated by less than their length; body 2.4–2.9 × as long as wide; elytral declivity steep, rounded................................................................... 2

- Malagasy species; interstrial setae rather short, in all except two species separated by their length or more, or if not, stout species <2.4 × as long as wide, or elytral apex extended......................................................... 6

2 Interstrial setae of variable length, the overall appearance dotted or slightly variegated; sutures on antennal club weakly procurved, almost bisinuate; length 2.4–2.5 mm ................................................. D. widdringtoniae

- Interstrial setae of fairly similar length; sutures on antennal club strongly procurved; length <2.0 mm.................. 3

3 Female frons densely pilose............................................................................ 4

- Female frons with short setae or glabrous on central half...................................................... 5

4 Broadest setae on posterior half of pronotum clearly spatulate; interstrial setae 2–3 × as long as wide, densely placed within rows, on interstriae 1 in part confused.............................................................. D. gracilis

- Broadest setae on posterior half of pronotum bristle-like; interstrial setae 3–5 × as long as wide, separated within rows by their length (or slightly less), setae on all interstriae uniseriate....................................... D. pilifrons sp. nov.

5 Female frons on central lower half glabrous, a broad ring of short setae around glabrous area; sutures on antennal club angulate................................................................................ D. calvifrons sp. nov.

- Female frons evenly covered by short setae, increasing slightly in length from vertex to epistoma; sutures on antennal club bisinuate.............................................................................. D. medius sp. nov.

6 Dorsal side of female scapus with long spike; female frons broadly concave, surface velvety; interstrial setae on declivity broader than on disc............................................................................ D. minor

- Female scapus broadly triangular with rounded edges; female frons never velvety; interstrial setae in most species spatulate on disc and declivity, if not, hair-like or absent, or elytral apex inflated............................................. 7

7 Elytral apex tapered or lightly inflated, posterolateral margins distinctly serrated; female frons with very dense, long brush of golden setae; anterior margin of pronotum forming a rim with raised teeth........................................ 8

- Elytral apex broadly rounded, declivity steep, posterolateral margins smooth or at most finely granulated; female frons usually moderately setose (if not, interstrial setae shaped as semi-recumbent scales and placed in irregular confused rows); anterior margin of pronotum without a rim....................................................................... 11

8 Antennal scapus in females distinctly angulate, falcate; female frons with a long dorsal tuft of projecting setae; elytral apex with only a slight inflation; interstrial setae on disk hair-like......................................... D. falcatus sp. nov.

- Female scapus not abruptly angulate; female frons with long setae recumbent downward, not projecting; elytral apex with obvious inflation or projection; interstrial setae spatulate throughout................................................ 9

9 Elytral apex distinctly tapered; interstrial setae in strict rows; female frons (if known) with one very broad and long tuft of setae.............................................................................................. 10

- Elytral apex inflated but not strongly tapered; interstrial setae in very slightly irregular rows; upper female frons with to short tufts of setae........................................................................ D. pulchellus sp. nov.

10 Interstrial setae truncated, about twice as long as broad................................................ D. ignotus

- Interstrial setae spatulate, not truncated, 3–4 × as long as broad.................................. D. acutior sp. nov.

11 Elytra with very short hair-like interstrial setae, appearing glabrous at low magnification.................. D. euphorbiae

- Elytra with distinct rows of erect interstrial setae........................................................... 12

12 Interstrial setae scale-like, semi-recumbent, some in irregular confused rows; female frons with long golden setae................................................................................................... D. catenatus

- Interstrial setae erect, in regular rows; female frons with short setae, never longer than width of club...................13

13 Interstriae 4–6 on declivity interrupted by stria 3, setae very closely placed in irregular rows; body 2.1 x as long as wide.......................................................................................... D. plenus sp. nov.

- All interstriae reaching elytral apex, setae usually in regular rows and spaced by their length or nearly so; body proportions variable, the majority of species more elongate............................................................ 14

14 Interstrial setae hairlike on disc, hair- or bristle-like on declivity; posterior half of elytra strongly tuberculate; antennal club with two transverse sutures................................................................ D. tuberculatus sp. nov.

- Interstrial setae spatulate; posterior and lateral margins of elytra nearly smooth (lightly granulated in two species); antennal club with two procurved sutures............................................................................ 15

15 Tiny species, 0.9–1.0 mm long, 2.1–2.2 × as long as wide........................................... D. rugosipes

- Larger species,> 1.4 mm long, all except one species 2.4–2.8 × as long as wide................................... 16

16 Posterolateral margins of elytra granulated; male frons deeply concave, smooth, impressed area just above upper level of eyes with two small and deeper pits.......................................................... D. granulatus sp. nov.

- Posterolateral margins of elytra at most finely rugose; male frons flattened, or impressed on lower half only............ 17

17 Stout species, 2.2 × as long as wide....................................................... D. robustus sp. nov.

- More elongated species, 2.4–2.8 × as long as wide.......................................................... 18

18 Pronotum long, elytra only 1.3–1.4 × as long as pronotum; setae on interstriae 1 irregular, spaced within rows by much less than their length................................................................................... D. obesus

- Elytra more elongated, 1.6–1.9 × as long as pronotum; all interstrial setae in regular rows, separated within rows by their length............................................................................................. 19

19 Elytral disc faintly impressed in middle; striae 3–6 lightly impressed; pronotal summit on posterior third... D. subdepressus

- Elytral disk flat; striae not impressed; pronotal summit at middle....................................... D. elongatus