Derelomus Schoenherr, 1825

Genus Derelomus Schoenherr, 1825

Derelomus signatus group

Species in this group exhibit a more or less dense cover of white scales on the lateral carina of pronotum ( Fig. 1C View Fig ). Their body is slender, the pronotum at most slightly wider than long (W: L ratio generally <1.30). The body of the penis is generally comparatively very long and apodemes very short (but see D. caldarai sp. nov. and D. karooensis sp. nov.). Eight species are recognized in this group, they are predominantly distributed in eastern and southern Africa, but one species extends to the Arabian Peninsula ( D. schoedli ) and one is found in North Cameroon, Cape Verde archipelago, Burkina Faso and Senegal ( D. lindbergi ). All species were collected on inflorescences of Mimosa L. and Vachellia Wight & Arn. ( Fabaceae ), which probably constitutes the host for larvae. This species group is likely more diverse than what is reported below. Several unique female specimens clearly belonging to new species were found in collections, but not described due to the lack of male or DNA grade material.

Derelomus pallidus group

This species group contains only three species, which exhibit a uniformly pale brown integument, a comparatively small body size, equal to or below 2.5 mm, and a lateral carina on the pronotum lacking a dense cover of white scales. The monophyly of this species group is supported by molecular data, at least for the two species D. pallidus and D. prochesi sp. nov. ( Fig. 33 View Fig ). Species in this group are restricted to East and southern Africa, they are associated with Ebenaceae and Achariaceae .

Derelomus nigrovariegatus group

This species group is defined by the combination of a glabrous lateral carina on the pronotum, the comparatively large body length (generally beyond 3 mm) and the prosternum at least partly dark brown. The protibiae of the males exhibit a distinct internal comb of erect setae and the sex dimorphism for the shape and curvature of the rostrum is marked (note that these features have not been verified in D. nigrovariegatus Hustache, 1936 due to the unavailability of males). Six species are recognized in this group, they are distributed in Central, East and southern Africa. Most species were collected on male inflorescences and in fruits of Phoenix reclinata Jacq. ( Arecaceae ) and one species develops in flowers of Strelitzia nicolai Regel & Körn. ( Strelitziaceae ).

Derelomus ephippiger group

This is the largest and possibly a non-monophyletic species group in Derelomus . Stable and simple synapomorphies to define it were not identified in the context of this study. The following combination of features should enable to distinguish this clade from the rest of the genus: lateral carina on pronotum glabrous, claw simple, prosternum uniformly pale brown (except in dark specimens of D. chamaeropis ), head concolorous or slightly darker than pronotum and stridulatory plate with compact lines of granules, space between granules as wide or narrower than diameter of a granule. Species in this group are generally either longer than 2.5 mm, with dark patterns on the elytra or with costate elytra and never lack these three features combined. The majority of species also exhibits the following features: presence of a post-ocular dark strip, lateral carina on pronotum with distinct notch or tooth near middle of length, pronotum distinctly transverse (W: L ratio at least 1.36) and elytra in males very wide, lens or pearshaped with 5 th interstriae raised (see D. piriformis ). This group is widely distributed in the study area and includes twelve species associated with male inflorescences of various palms ( Chamaerops L., Cocos L., Phoenix L.; Arecaceae ). Many species are found in sympatry, apparently sharing the same host and tissue. Several species concepts show geographic variants possibly corresponding to distinct species that would deserve more investigation.

Key to species of Derelomus Schoenherr, 1825

1. Lateral carina of pronotum glabrous or with minute setae not concealing the integument ( Fig. 1B View Fig ). Forehead glabrous or with scattered setae ( Fig. 1B View Fig ). Rostrum variable in size, as long as or distinctly longer than pronotum in lateral view in males ................................................................................. 9

– Lateral carina of pronotum concealed with whitish scales, or with a band of scales contrasting with the vestiture of the rest of pronotum ( Fig. 1C View Fig ). Forehead generally with two tufts of white scales near eyes ( Fig. 2A View Fig ). Rostrum comparatively short, generally as long as or slightly longer than pronotum in males in lateral view. On Fabaceae View in CoL ............................................................................................... 2

2. Elytra with two transverse stripes or lines of dark spots on each elytron ( Figs 2A View Fig , 3A View Fig , 4A View Fig ) .......... 3

– Elytra with one or no transverse band or line of dark spots on each elytron ( Figs 5A View Fig , 8A View Fig ). Some rare specimens of D. abyssinicus exhibit two bands on elytra, in that case the rostrum is almost straight in lateral view in both sexes ( Fig. 4B–C View Fig ) ......................................................................................... 5

3. Pronotum with white scales on dorsum ( Fig. 2A View Fig ). Claws appendiculate internally ( Fig. 1F View Fig ). On Vachellia spp. ......................................................................................... D. signatus Gyllenhal, 1836

– Pronotum with minute whitish setae, glabrous in appearance ( Figs 3A View Fig , 4A View Fig ). Claws simple ( Fig. 1F View Fig ) ............................................................................................................................................ 4

4. Rostrum as long as pronotum in lateral view ( Fig. 3B–C View Fig ). Pronotum distinctly transverse (W:L ratio: 1.33). Apex of elytra jointly rounded. Body of penis moderately elongate (W: L ratio: 0.37, Fig. 3D View Fig ); apodemes long, 0.8 × as long as body of penis. On Vachellia karroo View in CoL .. D. karooensis Haran sp. nov.

– Rostrum slightly longer than pronotum in lateral view ( Fig. 4B–C View Fig ). Pronotum isodiametric (W: L ratio: 1). Apex of elytra acuminate. Body of penis elongate (W: L ratio: 0.13); apodemes very short ( Fig. 4D View Fig ). On Vachellia xanthophloea View in CoL ................................................ D. acuminatus Haran sp. nov.

5. Rostrum regularly and moderately downcurved in lateral view ( Fig. 5B–C View Fig ). Claws simple ( Fig. 1F View Fig ). On Vachellia spp. ............................................................................... D. abyssinicus Hustache, 1936

– Rostrum in lateral view distinctly downcurved, more so near base ( Figs 6B–C View Fig , 7B–C View Fig , 8B–C View Fig ). Claws appendiculate ( Fig. 1F View Fig ) ..................................................................................................................... 6

6. Apex of body of penis rounded, not forming a long spatula ( Figs 6D View Fig , 7D View Fig ). Median area of stridulatory plate rounded at apex, with series of 4 granules ( Figs 6E View Fig , 7E View Fig ) ........................................................ 7

– Apex of body of penis expanded, forming a long spatula ( Figs 8D View Fig , 9D View Fig ). Median area of stridulatory plate more acute at apex, with series of 5–6 granules ( Figs 6E View Fig , 7E View Fig )................................................. 8

7. Elytra with a transverse dark line, sometimes reduced to a series of dots on even interstriae ( Fig. 6A– C View Fig ). Pronotum darker along medial line. Club darker than funicle in male ( Fig. 6A View Fig ). Southern and Eastern Africa ........................................................................................... D. caldarai Haran sp. nov.

– Body integument uniformly pale brown, some individuals with a dark spot beyond middle of length of interstriae 4 of elytra ( Fig. 7A View Fig ). Pronotum uniformly pale brown. Club and funicle concolorous ( Fig. 7A View Fig ). Cape Verde Archipelago, Cameroon and Senegal. On Vachellia View in CoL ........................................ ................................................................................................................. D. lindbergi Roudier, 1957

8. Body integument uniformly pale brown, elytra in some specimens with a dark spot beyond middle of length of interstriae 4 ( Fig. 8A View Fig ). Apex of penis body forming a spatula 2 × as long as wide, moderately bisinuate in lateral view ( Fig. 8D View Fig ). On Vachellia nilotica View in CoL ............................................... ............................................................................................................... D. pericarti Hoffmann, 1968

– Body integument pale brown, elytra with a line of dark spots beyond middle of length of interstriae 2, 4, 6 ( Fig. 9A View Fig ). Apex of penis body forming a spatula 4 × as long as wide, bisinuate in lateral view ( Fig. 9D View Fig ). On Vachellia View in CoL ...................................................................... D. schoedli Rheinheimer, 2005

9. Body integument uniformly pale brown ( Figs 10A View Fig , 11A). Smaller species, body length equal or below 2.5 mm. Males with smooth elytra. On Ebenaceae View in CoL and Achariaceae View in CoL .................................. 10

– Body with dark pattern on dorsum or with body length larger than 2.5 mm. In some species males with costate elytra ( Fig. 25A View Fig ). On Arecaceae View in CoL , Anacardiaceae View in CoL & Strelitziaceae View in CoL ............................. 12

10. Rostrum elongate, at least 5× as long as wide in dorsal view, distinctly longer than pronotum in lateral view ( Fig. 11C–D View Fig ). Metanepisterna with a dense vestiture of white scales ( Fig. 11F View Fig ). Claws appendiculate ( Fig. 1F View Fig ). Line of granules on stridulatory plate with spaces larger than width of a granule ( Fig. 11D, H View Fig ). On Achariaceae View in CoL ...........................................................................................11

– Rostrum short, at most 4 × as long as wide in dorsal view, as long as pronotum in lateral view ( Fig. 10B View Fig ). Metanepisterna with few non-overlapping white scales ( Fig. 10B View Fig ). Claws simple ( Fig. 1F View Fig ). Line of granules on stridulatory plate with spaces as wide as or narrower than width of a granule ( Fig. 10E View Fig ). On Ebenaceae View in CoL ........................................................................ D. pallidus Fåhraeus, 1844

11. Interstriae with erect setae as long as width of interstriae ( Fig. 11A View Fig ). Body of penis with sides converging regularly apicad in dorsal view ( Fig. 11C View Fig ) ............................... D. setifer Haran sp. nov.

– Interstriae with minute recumbent setae, shorter than width of interstriae ( Fig. 11E View Fig ). Body of penis with sides concave in middle of length in dorsal view ( Fig. 11G View Fig ). On Kiggelaria africana View in CoL ..................................................................................................... D. prochesi Haran sp. nov.

12. Integument of prosternum black, dark brown, or at least with contrasting dark patterns laterally ( Figs 12B View Fig , 14B, 17B). Pronotum moderately transverse, W:L ratio at most 1.30 ......................... 13

– Integument of prosternum uniformly pale brown ( Figs 19B View Fig , 21B View Fig ). Some specimens in D. chamaeropis have a dark prosternum ( Fig. 24D View Fig ), in this case, the elytra are uniformly brown ( Fig. 24C View Fig ). In most species pronotum distinctly transverse, W: L ratio at least 1.36 ( 1.23 in D. fasciatus ) .................. 18

13. Scutellar shield bearing a dense cover of whitish scales, concealing the integument ( Fig. 12A View Fig ). Endemic to South Africa, on Strelitzia nicolai View in CoL ( Strelitziaceae View in CoL ) .............. D. strelitziae Haran sp. nov.

– Scutellar shield glabrous or with a few setiform scales, not concealing the integument ( Fig. 13A View Fig ). Most species on Phoenix reclinata ................................................................................................. 14

14. Body integument uniformly black, shiny, antennal scape and tarsi dark brown or reddish ( Fig. 16A View Fig ). On Phoenix reclinata ...................................................................................... D. ater Marshall, 1950

– Body integument brown ( Fig. 15A View Fig ) sometimes with pale patterns ( Fig. 17A View Fig ) or pale brown with dark patterns on dorsum ( Figs 13A View Fig , 14A) .............................................................................................. 15

15. Dorsal face of pronotum and elytra very flat in lateral view ( Fig. 13B–C View Fig ). Apical constriction of pronotum very deep in dorsal view ( Fig. 13A View Fig ). Stridulatory plate with granules closely aligned; line of granules shorter than half the length of stridulatory plate ( Fig. 13E View Fig ). On Phoenix reclinata ............ ............................................................................................................ D. strangulatus Haran sp. nov.

– Pronotum and elytra convex dorsally in lateral view ( Figs 14B View Fig , 15B View Fig ). Apical constriction of pronotum shallow or absent in dorsal view ( Figs 14A View Fig , 15A View Fig ). Stridulatory plate with granules distantly aligned or line of granules longer than half the length of stridulatory plate ( Figs 14F View Fig , 15F View Fig ) ...................... 16

16. Integument of prosternum uniformly dark brown ( Figs 15B View Fig , 17B View Fig ) ............................................... 17

– Integument of prosternum pale brown with dark patterns laterally ( Fig. 14B View Fig ). On Phoenix reclinata .................................................................................................................. D. zonatus Marshall, 1950

17. Sides of pronotum very convex in dorsal view, apical margin about 0.5 × as wide as width of pronotum near middle of length ( Fig. 15A View Fig ). Scutellar shield darker than elytra. Eyes very convex in dorsal view, exceeding distinctly the lateral curve of the head capsule. On Phoenix reclinata .................................................................................................. D. brunneus Haran sp. nov.

– Sides of pronotum moderately convex in dorsal view, apical margin about 0.75 × as wide as width of pronotum near middle of length ( Fig. 17A View Fig ). Scutellar shield pale brown, concolorous with pale patterns on elytra. Eyes moderately convex in dorsal view, exceeding slightly the lateral curve of the head capsule ................................................................................ D. nigrovariegatus Hustache, 1936

18. Head black, contrasting strongly with color of body integument ( Fig. 18A View Fig ). Pronotum with a contrasting dark spot near the scutellar shield ....................................... D. trinotatus Haran sp. nov.

– Head concolorous or slightly darker than body, not contrasting strongly with color of the rest of body ( Figs 19A View Fig , 20A View Fig ). Pronotum uniformly pale brown, or with a dark median line, not forming a dark spot near the scutellar shield ( Figs 20A View Fig , 28A) ............................................................................... 19

19. Rostrum very long and almost straight in lateral view, in males at least 1.3× as long as pronotum ( Figs 19B View Fig , 20B View Fig ). Body of penis long and narrow, W: L ratio at most 0.23 ( Figs 19D View Fig , 20D View Fig ). Stridulatory plate with granules indistinct or with space between granules wider than diameter of a granule ( Figs 19E View Fig , 20E View Fig ). Head capsule lacking a distinct postocular dark strip ( Fig. 19B View Fig ) ........... 20

– Rostrum comparatively short and more downcurved, at most 1.28 × as long as pronotum in lateral view in males ( Figs 21B View Fig , 22B). Body of penis moderately elongate, W: L ratio at least 0.25 ( Fig. 21D View Fig ), except for D. antonioui : (0.18; Fig. 22D View Fig ). Stridulatory plate generally with compact and distinct lines of granules ( Fig. 24F View Fig ). Head capsule generally with a more or less contrasting postocular dark strip ( Fig. 30D View Fig ) ...................................................................................................... 21

20. Smaller species, body size < 2.5 mm ( Fig. 19A View Fig ). Pronotum isodiametric. Elytra generally at least with a transverse dark strip beyond middle of length. Stridulatory plate with lines of 4–5 granules ( Fig. 19E View Fig ). Sides of body of penis converging apicad, apex truncate ( Fig. 19D View Fig ). On Searsia glauca View in CoL ................................................................................................... D. fasciatus Hartmann, 1904

– Larger species, body size> 3 mm ( Fig. 20A View Fig ). Pronotum transverse. Elytra generally uniformly pale brown or with dark shades laterally and at apex ( Fig. 20B View Fig ). Stridulatory plate lacking distinct lines of granules ( Fig. 20E View Fig ). Sides of body of penis widening apicad, apex forming a spatula ( Fig. 20D View Fig ). On Phoenix reclinata ............................................................................ D. languidus Fåhraeus, 1844

21. Elytra shorter, at most 2.4 × as long as pronotum ( Fig. 21A View Fig ). Dark patterns on elytra forming two transverse strips, one at base between interstriae 1–7 and one slightly after middle of length, the latter sometimes reduced to a small spot on each elytron ( Fig. 21A View Fig ). Protibiae in males with a ventral comb of setae on apical half, setae about as long as 4 th tarsomere. On Cocos nucifera View in CoL ......................................................................................................... D. brevis Haran sp. nov.

– Elytra longer, at least 2.45 × as long as pronotum ( Figs 22A View Fig , 28A View Fig ). Body integument uniformly pale brown or with dark patterns not forming two transverse bands. Protibiae in males with or without a ventral comb of setae on apical half ............................................................................................... 22

22. Rostrum distinctly longer than pronotum in both sexes, at least 1.2–1.5× as long as pronotum in lateral view ( Figs 22B–C View Fig , 26B–C View Fig , 27B View Fig ). Curvature of rostrum moderate ..................................... 23

– Rostrum comparatively shorter, at most 1.15 × as long as pronotum in lateral view in males ( Figs 24B View Fig , 25C, 28B), sometimes longer in females. Curvature of rostrum variable, moderate or strong ( Figs 28B View Fig , 32B View Fig ) ................................................................................................................... 26

23. Elytra with a large and contrasting dark spot beyond middle of length on each elytron ( Fig. 23A View Fig ), sometimes merged into a transverse dark strip. Pronotum uniformly pale brown. Body of penis very elongate, 4 × as long as wide in dorsal view, with sides concave ( Fig. 23D View Fig ). On Phoenix reclinata ................................................................................................ D. postfasciatus Hesse, 1929

– Elytra uniformly pale brown or with dark patterns arranged differently ( Figs 22A View Fig , 26A View Fig , 27A View Fig ). Pronotum uniformly pale brown or with a median dark line ( Figs 22A View Fig , 26A View Fig ). Body of penis variable, elongate or short ( Figs 22D View Fig , 27C View Fig ) .................................................................................................. 24

24. Pattern on elytra variable, but most specimens with a dark spot at base around scutellar shield and one on suture, slightly beyond middle of length ( Fig. 22A View Fig ). Stridulatory plate with lines of granules distinctly converging apicad ( Fig. 22E View Fig ). Eastern Mediterranean region and Arabian Peninsula, on Phoenix dactylifera and P. canariensis ...................................................... D. antonioui Alziar, 2007

– Elytra uniformly pale brown, or with dark patterns not forming two spots on suture ( Figs 26A View Fig , 27A View Fig ). Stridulatory plate with lines of granules subparallel or only slightly converging apicad ( Fig. 26E View Fig ). Afrotropical region ......................................................................................................................... 25

25. Body comparatively elongate ( Fig. 26A View Fig ), elytra slender (W: L ratio 0.6–0.70). Protibiae in males with short setae. Club dark brown, darker than funicle segments. Body of penis with sides concave near middle of length in dorsal view, apex curved upward in lateral view ( Fig. 26D View Fig ). On Phoenix reclinata .................................................................................................... D. peglerae Haran sp. nov.

– Body comparatively short ( Fig. 27A View Fig ), elytra more compact (W: L ratio 0.75). Protibiae in males long erect setae. Club pale brown, concolorous with funicle segments. Body of penis with sides slightly convex near middle of length in dorsal view, apex bisinuate in lateral view ( Fig. 27C View Fig ) ........................................................................................................ D. baka Haran sp. nov.

26. Sides of elytra subparallel in dorsal view ( Fig. 24A–B View Fig ). Pronotum almost as wide as elytra near middle of length, at least 0.8× the width of elytra. On chamaerops humilis View in CoL ..................................... ....................................................................................................... D. chamaeropis ( Fabricius, 1798)

– Sides of elytra convex or very convex and lens-shaped in dorsal view ( Figs 25A View Fig , 26A View Fig ). Pronotum distinctly narrower than elytra near middle of length, at most 0.70 × the width of elytra .............. 27

27. Elytra widest beyond middle of length ( Fig. 25A–B View Fig ). Body integument uniformly pale brown; head capsule sometimes darker, but not exhibiting a contrasting postocular dark strip ( Fig. 25C–D View Fig ). Protibiae of males with a comb of setae. On Phoenix canariensis .. D. piriformis ( Hoffmann, 1938)

– Elytra widest at or before middle of length ( Fig. 26A View Fig ). Body integument uniformly pale brown or with dark patterns; head capsule with a more or less contrasting postocular dark strip ( Figs 26A View Fig , 27A View Fig ). Protibiae of males with or without a comb of setae ............................................................. 28

28. Rostrum strongly downcurved in lateral view, almost forming a quarter circle ( Figs 28B–C View Fig , 29B– D View Fig ) .................................................................................................................................................... 29

– Curvature of rostrum moderate in lateral view, not forming a quarter circle ( Fig. 30C–D View Fig ) ........... 30

29. Body wider ( Fig. 28A View Fig ); elytra in males very convex laterally, distinctly wider than width of prothorax. Prothorax wider (W: L ratio: 1.54). Rostrum bicoloured, showing black areas laterally and apically ( Fig. 28B–C View Fig ). Club black. On Phoenix reclinata ................................. D. bivirgatus Marshall, 1951

– Body narrower ( Fig. 29A–B View Fig ); elytra in males moderately convex laterally, not much wider than width of prothorax. Prothorax narrower (W:L ratio: 1.43–1.50). Rostrum uniformly brown, ( Fig. 29B–D View Fig ), lacking contrasting black areas. Club pale brown, concolorous with funicles segments in females ( Fig. 29C View Fig ). Brown in males ( Fig. 29A View Fig ). On Phoenix reclinata ............... D. crypticus Haran sp. nov.

30. Elytra in male uniformly pale brown ( Fig. 30A View Fig ). Club dark brown. Stridulatory plate with series of 7 or more granules ( Figs 30F View Fig , 31E View Fig ) ................................................................................................ 31

– Elytra with a large brown scutellar spot, located between 4 th interstriae and extending beyond middle of length in both sexes ( Fig. 32A View Fig ). Club and funicle concolorous, pale brown. Stridulatory plate with series of 5–6 granules ( Fig. 32E View Fig ) ....................................................... D. ephippiger Gyllenhal, 1836

31. Rostrum in male as long as pronotum in lateral view, slightly and regularly downcurved (30C); in dorsal view about 3.5× as long as wide. Internal margin of protibiae in male with short and recumbent setae, not contrasting with the rest of the coating. Body of penis bisinuate at apex in lateral view ( Fig. 30E View Fig ). Stridulatory plate with series of 7–8 granules ( Fig. 30F View Fig ). On Phoenix reclinata .... .................................................................................................................. D. costiger Marshall, 1958

– Rostrum in male longer than pronotum in lateral view, comparatively more downcurved ( Fig. 31B View Fig ); in dorsal view about 4.75 × as long as wide. Internal margin of protibiae in male with a comb of long erect setae, longer than length of claw ( Fig. 31D View Fig ). Body of penis downcurved at apex in lateral view ( Fig. 31C View Fig ). Stridulatory plate with series of 11–12 granules ( Fig. 31E View Fig ). On Phoenix reclinata ....................................................................................................... D. discus Haran sp. nov.

Molecular analyses

DNA-grade specimens were obtained for 19 of the 32 known species of Afrotropical and Mediterranean Derelomus . For COI data alone, the lowest interspecific distance was observed between D. caldarai and D. schoedli (7.6%), while the highest intraspecific distance was observed in D. chamaeropis between the Moroccan and Spanish populations (3.4%). The species concepts recovered by morphology were consistent with the best-fit ML tree inferred in IQ-TREE from the analysis of the concatenated dataset, where all species represented by several individuals were found to be monophyletic ( Fig. 33 View Fig ). The genus Derelomus was recovered monophyletic, with moderate support (SH-aLRT of 83.4% and uBV of 64%). Within Derelomus , interspecific relationships were not highly supported (only four nodes out of 18 have both SH-aLRT>80% and uBV values>95%); however, nodes leading to specimens belonging to multiple specimens of the same species were generally highly supported (nine nodes out of 12 have both SH-aLRT>80% and uBV values>95%).

Molecular species delimitation analyses based on the COI dataset were highly consistent with the morphological concepts of species, as the results of most SD analyses support extant species boundaries ( Fig. 34 View Fig ). A potential lumping of species was inferred only once with the ASAP analysis, between D. pallidus and D. prochesi . Potential intraspecific splits were found twice in the bPTP analysis (for D. schoedli and D. trinotatus ), once in the PTP(ML) analysis (for D. schoedli ) and three times in the GMYCm analysis (for D. fasciatus , D. peglerae and D. prochesi ).