Macrocheilus Hope 1838
Creators: name: Serrano, Artur R. M.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Macrocheilus

description: Key to the Afrotropical (excluding Madagascar) Macrocheilus species
An identification key for the Afrotropical species/subspecies is provided, including the new species. The Macrocheilus species /subspecies from Madagascar can be identified through Jeannel (1949) and Basilewsky (1953).
Since the diagnostic external morphological characters are similar for males and females, the key can be used for both sexes. Macrocheilus basilewskyi and M. dorsalis are identified in any alternative dichotomic step 5 [larger species (length ≥ 10 mm) vs. smaller species (length<10 mm)], since both can present specimens within these options. After reaching the identification of a species, other characters can be added, reinforcing its diagnosis (e.g. labrum and/or pronotum shapes/features, elytra patches, male and/or female genitalia).
1. Last maxillary palpomere barrel twisted shaped; labrum asymmetric, with a pair of marginal or submarginal lateral setae in the middle (Figs 1g, 2e, 5i, 6e)............................................................................. 2
- Last maxillary palpomere more or less securiform shaped; labrum symmetric, with more than one pair of setae (e.g. Figs 1b, 2a)................................................................................................ 3
2. Elytra black, intervals smooth, one pair of a more or less ovoid orange-yellowish spots in the end of the basal half throughout the 3 rd to 6 th or 7 th intervals; head and pronotum more densely punctured; posterior angles of pronotum slightly dentiform at apex, with a slight short expansion just before the angles; male and female genitalia as in figures 7c and 8d, respectively.................................................................................. M. labrosus (Dejean, 1831)
- Elytra totally black, intervals with a very thin polygonal microreticulation; head and pronotum less densely punctured; posterior angles of pronotum rounded, without any expansion before the angles; male genitalia as in figure 3d.................................................................................................. M. alluaudi Burgeon, 1937
3. Elytra microreticulate.................................................................................. 4
- Elytra smooth, without microreticulation................................................................... 7
4. Posterior angles of pronotum slightly obtuse; elytra moderately microreticulate.................................... 5
- Posterior angles of pronotum strongly obtuse; elytra strongly microreticulate..................................... 6
5. Head, pronotum and elytra black; posterior angles of pronotum slightly dentiform at apex; one pair of orange spots jagged in the median discal zone (Fig. 15d).................................................... M. crampeli Alluaud, 1916
- Head and pronotum dark brown, almost black; elytra dark brown-reddish; posterior angles of pronotum slightly rounded at apex; one pair of orange spots round shaped in the median discal zone, with a black hole (Fig. 16a)................................................................................................ M. ocellatus Basilewsky, 1953
6. Legs brown, or at least coxae, trochanters and femora brown; pronotum strongly sinuate just anterior to posterior angles (Figs 11f, g); anterior half of labrum strongly ogive shaped, three marginal/submarginal pairs of setae (Fig. 12d); male and female genitalia as in figures 13d and 14d, respectively (in the nominotypical subspecies the legs are totally black)................................................................................ M. viduatus katanganus Basilewsky, 1960
- Legs black; pronotum less sinuate just anterior to posterior angles (Fig. 5b); anterior half of labrum less ogive shaped, three marginal/submarginal pairs of setae (Fig. 2h); male genitalia as in Serrano (2000, Figs. 1–2); female genitalia as in figure 8a............................................................................ M. bimaculatus (Dejean, 1831)
7. Larger species (length ≥ 10 mm)......................................................................... 8
- Smaller species (length <10 mm)....................................................................... 29
8. Head black and pronotum ferruginous or head and pronotum black or dark brown; elytra black or dark brown with orange or yellowish spots...................................................................................... 9
- Head and pronotum ferruginous, orange or brownish; elytra with dark patches and orange or yellowish spots........... 17
9. Head black and pronotum ferruginous; pronotum slightly transverse; elytra black with a pair of ovoid orange-yellowish spots in the end of first half (Fig. 16b).................................................... M. overlaeti Burgeon, 1937
- Head and pronotum black or dark brown; elytra black or dark brown with orange or yellowish spots.................. 10
10. Pronotum slightly transverse (1.1–1.2 times wider than long); elytra slender...................................... 11
- Pronotum more transverse (1.45–1.75 times wider than long); elytra broader..................................... 12
11. Posterior angles of pronotum strongly obtuse, sharpish, without expansion before the angles; elytra 1.9 times longer than wide, one pair of orange spots in the median discal zone (Fig. 5h); anterior half of labrum ogive shaped, two pairs of marginal setae, one pair of setae in the middle of the disc, margins of posterior half subparallel (Fig. 6d); female genitalia as in figure 8c................................................................................ M. hybridus Péringuey, 1896
- Posterior angles of pronotum obtuse, rounded at apex, a slight short expansion just before the angles; elytra 2.1 times longer than wide, one pair of orange spots in the median discal zone (Fig. 15a)................. M. angustatus Basilewsky, 1949
12. Legs with trochanters and femora brown, tibia and tarsi blackish; anterior half of labrum ogive shaped, two marginal pairs of setae, one submarginal pair of setae (Fig. 2g); posterior angles of pronotum strongly obtuse, dentiform, a slight short expansion just before the angles; male and female genitalia as in figures 3e and 4e,f, respectively......... M. biguttatus (Gory, 1832)
- Legs totally black; body slightly or densely punctured....................................................... 13
13. Pronotum strongly sinuate just anterior to posterior angles, which are strongly obtuse, not dentiform at apex; elytra with one pair of large orange or yellowish spots (3 rd to 7 th intervals) (Fig. 5g); anterior half of labrum ogive shaped, three marginal pairs of setae; male genitalia as in figure 7b............................................. M. elegantulus Burgeon, 1937
- Pronotum not strongly sinuate just anterior to posterior angles which are strongly obtuse, dentiform or rounded; elytra with one pair of smaller orange or yellowish spots................................................................. 14
14. Anterior half of labrum round shaped, two marginal pairs of setae and one discal pair of setae (Fig. 6a); pronotum transverse (1.4 times wider than long), posterior angles of pronotum rounded; elytral intervals almost flat, second interval with two rows of punctures; male genitalia as in figure 3f. ....................................... M. diplospilus Basilewsky, 1967
- Anterior half of labrum ogive shaped, three marginal pairs of setae (e.g. Fig. 2i).................................. 15
15. Head and pronotum not so densely punctured; posterior angles of pronotum slightly obtuse, dentiform at apex, a slight expansion before the posterior angles; elytra with one pair of small orange spots (3 rd to 6 th intervals) (Fig. 15c); male genitalia as in Basilewsky (1967, Figs. 2c, 3c).................................................. M. burgeoni Basilewsky, 1967
- Head and pronotum strongly and densely punctured; male genitalia with a different shape.......................... 16
16. Elytra with one pair of small orange spots (3 rd to 7 th intervals) (Fig. 5c); Male genitalia as in Basilewsky (1967, Figs. 2b, 3b); female genitalia as in figure 8b................................................. M. clasispilus Basilewsky, 1967
- Elytra with one pair of small orange spots (3 rd to 6 th intervals) (Fig. 16e); Male genitalia as in Basilewsky (1967, Figs. 2a, 3a)............................................................................. M. vinctus Basilewsky, 1960
17. Elytra with medium to large orange or yellowish spots (e.g. Fig. 9b)............................................ 18
- Elytra with small orange or yellowish spots (e.g. Fig. 11b)................................................... 27
18. Elytra with one pair of spots........................................................................... 19
- Elytra with two pairs of spots, separated or coalescent....................................................... 20
19. Anterior half of labrum ogive shaped; pronotum as wide as long, not heart-shaped; elytra with orange spots as in figure 1e............................................................................... M. allardi Basilewsky, 1957
- Anterior half of labrum round shaped; pronotum transverse (about 1.30 wider than long), heart-shaped; elytra with orange spots as in figure 15b............................................................ M. biplagiatus (Boheman, 1848)
20. Pronotum as wide as long, posterior angles strongly obtuse, slightly sharp at apex; anterior half of labrum ogive shaped, two marginal pairs of setae, one submarginal pair of setae (Fig. 10a); elytra with orange spots and dark patches as in figures 9b, c; male genitalia as in figure 7d.................................................... M. longicollis Péringuey, 1904
- Pronotum transverse, wider than long (1.22–1.46 times)...................................................... 21
21. Anterior half of labrum round shaped.................................................................... 22
- Anterior half of labrum triangular or ogive shaped, two marginal or submarginal or discal pairs of setae (e.g. Figs. 2c, f, 6b). .................................................................................................. 23
22. Anterior half of labrum with two marginal pairs of setae, one pair of setae beneath the anterior margin near apex (Fig. 10b); elytra with orange spots and dark patches as in figures 9d, e; male genitalia as in figure 13a...................................................................................................... M. persimilis Basilewsky, 1970
- Anterior half of labrum with three marginal pairs of setae; elytra with yellowish spots and dark patches as in figure 15e.................................................................................... M. cruciatus (Marc, 1840)
23. Larger species (length> 11.5 mm); anterior half of labrum almost triangular shaped............................... 24
- Smaller species (10–11.5mm); anterior half of labrum ogive shaped............................................ 25
24. Margins of posterior half of labrum subparallel (see Felix & Muilwijk 2007, Fig. 4); orange spots and dark patches of elytra as in Felix & Muilwijk (2007, Fig. 1)......................................... M. vanharteni Felix & Muilwijk, 2007
- Margins of posterior half of labrum parallel (Fig. 2c); elytra with orange spots and dark patches as in figure 1c; male and female genitalia as in figures 3b and 4b, respectively.............................................. M. philippeorum n. sp.
25. Posterior angles of pronotum slightly obtuse, rounded or very slightly sharp at apex, without expansion just before the angles; anterior half of labrum with one discal pair of setae (Fig. 2f); orange spots and dark patches as in figure 1h; male genitalia as in Serrano (2000, Figs. 13, 14), female genitalia as in figure 4d............................. M. basilewskyi Serrano, 2000
- Posterior angles of pronotum strongly obtuse and dentiform at apex, a slight short expansion just before the angles; anterior half of labrum without a discal pair of setae (Figs. 6b, 10d)...................................................... 26
26. Sutural dark patch of elytra becoming a discoidal one, reaching the 4 th striae from the base to about one-fourth of the length, widening obliquely from there to near both the lateral and apical margins (Figs. 9f, g); male genitalia as in Serrano (2000, Figs. 15, 16), female genitalia as in figure 14a............................................. M. proximus Péringuey, 1896
- Dark drop-like patch of elytra along the suture reaching almost the lateral margins in its largest wide, getting too far from the apical margin (Fig. 5e); male genitalia as in figure 7a...................................... M. dorsalis Klug, 1834
27. Anterior half of labrum strongly ogive or even triangular shaped, with three pairs of marginal setae (Fig. 12c); elytra dark brown, about twice as long as wide, with 2 orange spots (Figs. 11d, e); male genitalia as in Basilewsky (1960, Figs. 2b, e); female genitalia as in figure 14c.................................................. M. taedatus Basilewsky, 1960
- Anterior half of labrum ogive shaped, two pairs of marginal setae, one pair of discal setae (e.g. Fig. 12b); elytra brownish or blackish, about 1.6–1.7 times longer than wide, with 4 orange spots (Figs. 11b, c, 15f)............................. 28
28. Larger species (14–19 mm); Body more densely punctured; margins of posterior half of labrum subround (Fig. 12c); elytra orange spots as in figures 11b, c; male genitalia as in figure 13c (see also Serrano 2000, Figs. 9, 10)............................................................................................... M. spectandus Péringuey, 1904
- Smaller species (11.6–11.8 mm); Body less densely punctured; margins of posterior half of labrum subparallel; elytra orange spots as in figure 15f; male genitalia as in Serrano (2000, Figs. 7, 8)......................... M. moraisi Serrano, 2000
29. Body totally black; anterior half of labrum strongly rounded, two pairs of marginal setae, one pair of setae in the middle of the disc, margins of posterior half rounded (Fig. 2a); pronotum slightly cordiform, posterior angles slightly obtuse and rounded, anterior submarginal area wrinkled; female genitalia as in figure 4a.............................. M. assmanni n. sp.
- Body colour not as above.............................................................................. 30
30. Head blackish; pronotum testaceous-redish; elytra blackish concolorous (Fig. 16c) [elytra with one pair of a longitudinal redyellowish patch spread throughout the 4 th, 5 th, 6 th and part of 7 th intervals since the base to the median region of the disc in the subspecies M. varians eugrammus Basilewsky, 1960 (Fig. 16d)]................... M. varians varians Péringuey, 1904
- Body colour not as above............................................................................. 31
31. Head and pronotum black or dark brown; elytra black or dark brown with orange-brownish or yellowish spots.......... 32
- Head and pronotum orange-yellowish or brownish; almost all elytra brownish or yellowish with drop-like dark markings... .................................................................................................. 35
32. Elytra with two pairs of orange-brownish spots (Figs. 9h, i), one row of punctures in the first interval; margins of anterior half of labrum strongly rounded, two pairs of marginal setae, one pair of setae in the middle of the disc, margins of posterior half rounded (Fig. 10d); pronotum slightly cordiform, posterior angles right and rounded; female genitalia as in figure 14b................................................................................ M. quadrinotatus Burgeon, 1937
- Elytra with one pair of orange-brownish spots............................................................. 33
33 Elytra with one pair of ovoid orange-brownish spots in the middle region; body densely punctured; anterior half of labrum ogive shaped, two marginal pairs of setae, one submarginal pair of setae (Fig. 2b); posterior angles of pronotum strongly obtuse, dentiform at apex, a slight short expansion just before the angles; legs totally brown; male genitalia as in figure 3a.............................................................................................. M. kudrnai n. sp.
- Elytra with one pair of longitudinal orange-brownish spots spread throughout the first half not reaching the base........ 34
34. Pronotum strongly cordiform, posterior angles acute and rounded; anterior half of labrum slightly ogive shaped, three pairs of marginal setae (Fig. 12a); knee, tibia and tarsi blackish, femora brownish (Fig. 11a); male genitalia as in figure 13b..................................................................................... M. scapularis (Reiche, 1843)
- Pronotum slightly cordiform, posterior angles right or even slightly obtuse and rounded at apex; anterior half of labrum ogive shaped, two pairs of marginal setae, one submarginal intermedium pair (Fig. 2d); legs brownish (Fig. 1d); male and female genitalia as in figures 3c and 4c, respectively................................................. M. schuelei n. sp.
35. Posterior angles of pronotum slightly obtuse, rounded or very slightly sharp at apex, without expansion just before the angles; anterior half of labrum with one discal pair of setae (Fig. 2f); orange spots and dark patches as in figure 1h; male genitalia as in Serrano (2000, Figs. 13, 14), female genitalia as in figure 4d............................. M. basilewskyi Serrano, 2000
- Posterior angles of pronotum obtuse and dentiform at apex; orange spots and dark patches not as in figure 1h........... 36
36. Larger species (8–10 mm); head and pronotum densely punctured (Fig. 5e); pronotum more transverse (1.3 times larger than long), a slight short expansion just before the posterior angles; anterior half of labrum ogive shaped, three pairs of marginal setae (Fig. 6b); dark drop-like patch of elytra along the suture reaching almost the margins in its largest wide (Fig. 5e); male genitalia as in figure 7a.............................................................. M. dorsalis Klug, 1834
- Smaller species (6–8 mm); head and pronotum less densely punctured (Fig. 5f); pronotum less transverse (1.2 times larger than long), without short expansion just before the posterior angles; anterior two thirds of labrum strongly triangular shaped, three pairs of marginal setae (Fig. 6c); dark drop-like patch of elytra along the suture narrower in its largest wide (Fig. 5f); male genitalia as in Serrano (2000, Figs. 3, 4)............................................ M. dorsiger (Chaudoir, 1876)
description: Published as part of Serrano, Artur R. M., 2023, Afrotropical ground beetles of Macrocheilus Hope, 1838 (Coleoptera, Carabidae) description of four new species and faunistic notes, pp. 1-35 in Zootaxa 5256 (1) on pages 29-31, DOI: 10.11646/zootaxa.5256.1.1, http://zenodo.org/record/7745281