Lethrus, Scopoli, 1777

Bagaturov, Mikhail F. & Hillert, Oliver, 2023, Sinolethrus, a new subgenus of the genus Lethrus Scopoli, 1777 from China (Coleoptera: Geotrupidae: Lethrinae) and new synonymy of the subgenus Paralethrus Nikolajev, 2003, Zootaxa 5258 (3), pp. 301-316 : 305

Identification key of the subgenera of the genus Lethrus based on well-developed male specimens

1 Dorsal surface of mandible completely flat, without any slanting, transverse carina (tc) or hornlike protrusion (mhp) ( Figs. 24–26 ); fragmented distribution: SE Turkmenistan, NW Afghanistan, S Tajikistan, E Uzbekistan, S Kirgizia, SE Kazakhstan, W China, S Mongolia, N China............................................... Heteroplistodus B. Jakovlev, 1890

– Dorsal surface of mandibles with distinct transverse carina (tc) or hornlike protrusion (mhp) on left mandible surface, sometimes ambilateral ( Figs. 9–23 , 27–35 , 37–54 )..................................................................... 3

3 Dorsal surface of left mandible with more or less distinct hornlike protrusion (mhp) directed inward and backward ( Figs. 9–17 ); mandibular appendix (ma) on left mandible well developed, on right one less developed or absent..................... 4

– Dorsal surface of left mandible with slanting or transverse carina (tc) of different characteristics but never hornlike directed inward and backward ( Figs. 18–23 , 27–35 , 37–54 ); mandibular appendix (ma) differently developed, symmetrical or one side more developed or sometimes completely absent on both sides, as in females...................................... 5

4 Dorsal surface of left mandible with short hornlike protrusion (mhp) at middle of length, directed to the right sideward (90°) ( Figs. 13–14, 17 , 58 ); right mandible without any apophysis or carina on surface of mandible; mandibular appendix (ma) on left mandible subparallel with mandibular outline; apex of left mandible on lower side without apophysis; right mandible without appendix (ma); apical spur of front tibia without subbasal elevation ( Fig. 55 ); mandibles shorter than head ( Figs. 17 , 58 ); mentum strongly convex in side aspect ( Fig. 61, 64 ); parameron longer ( Figs. 3–4 ); distributed in NC China ( Fig. 65 )............................................................... Sinolethrus Bagaturov & Hillert, new subgenus

– Dorsal surface of left mandible with more elongate hornlike protrusion (mhp) in middle of length of mandible, directed to the right sideward and backward (45°) ( Figs. 15–16 ); right mandible with distinct mandibular protrusion (mp) on surface reaching to lateral mandibular outline ( Figs. 9–12 ); mandibular appendix (ma) on left mandible more or less parallel with mandibular outline approximately ( Figs. 10, 12 ); subapical tooth (sat) on lower side of left mandible well developed ( Figs. 9, 11 ); right mandibular appendix (ma) more or less developed but noticeable shorter than left one; apical spur of front tibia with subbasal elevation (fig. 56); mandibles more long than head; mentum not convex, flat in side aspect; parameron shorter ( Figs. 1– 2 ); distributed in S Kazakhstan, NW Uzbekistan, N Kyrgyzstan and S Russia....... Ceratodirus Fischer von Waldheim, 1845

5 Profemur armed on frontal edge with keels or apical apopyhses; mandibular appendix (ma) more or less symmetrical, if asymmetrical then right one more developed ( Figs. 27–29 ); fragmented distribution: S Turkmenistan, NE Iran, S Uzbekistan, W Tajikistan, N Afghanistan, S Uzbekistan, S Kirghizia................................. Scelolethrus Semenov, 1832

– Profemur unarmed on frontal edge........................................................................ 6

6 Metafemur of male with distinct concavity on rear edge ( Fig. 36 ); mandibular appendix (ma) distinct asymmetrically, right appendix more developed; distributed in W Turkmenistan and NE Iran.................... Teratolethrus Semenov, 1894

– Metafemur of male without concavity on rear edge, without keels or apical apophyses at middle of length, plain or only weakly transverse keel-like ridge developed...................................................................... 7

7 Both mandibles without appendices (ma), as in females. Transverse carina (tc) on dorsal surface of apex of left mandible reaching to lateral mandibular outline, clearly delimited ( Figs. 46–48 ); distributed in S Kazakhstan, E Uzbekistan and W Kirgizstan..................................................................... Abrognathus Jakovlev, 1890

– Both mandibles with or without appendices (ma). If mandibles without appendices, transverse carina (tc) on dorsal surface of apex of left mandible not reaching to mandibular outline, surface between apex of mandibles and transverse carina (tc) never clearly delimited ( Figs. 49–51 )........................................................................... 8

8 Mandibular appendices (ma) blade-shaped, strongly symmetrical and projecting laterally in dorsal aspect, transverse carina (tc) on dorsal surface of apex of left mandible reaching to lateral mandibular outline ( Figs. 52–54 ); probably distributed in Turkmenistan (Turkmenbashi distr.).................................................. Neolethrus Nikolajev, 1987

– Mandibular appendices (ma) different shaped, transverse carina (tc) on dorsal surface of apex of left mandible never reaching to lateral mandibular outline............................................................................. 9

9 Mandibular appendices (ma) distinctly asymmetric, left one mostly S-shaped, directed forward and downward (exceptional L. antovae Medvedev, 1957 , both mandibles S-shaped in frontal aspect, symmetrical), left appendix distinctly more strongly developed and more elongate ( Figs. 18–23 ); distributed in Tajikistan (Ghissar-Darwaz Mts.) and S Kirgizia........................................................................................... Furcilethrus Nikolajev, 1968

– Mandibular appendices not distinctly asymmetric; left one not mostly S-shaped and not distinctly more developed than right one............................................................................................... 10

10 Apex of parameres straight acuminate apically and distinct flattened in lateral view ( Fig. 6, 8 ); distributed in S Kazakhstan (western Tien Shan Mts.), NW Kirgizia and E Uzbekistan.............................. .. Paralethrus Nikolajev, 2003

– Apex of parameres acuminate or broadly rounded in dorsal aspect ( Figs. 7–8 ) but not flattened apically in lateral view ( Fig. 5 )................................................................................................. 11

11 Both mandibles without appendices (ma), as in females ( Figs. 49–51 ); distributed in S Uzbekistan (West of Ghissar-Darwaz Mts.), NW Tajikistan, W Kirgizia, S Kazakhstan....................................... Mesolethrus Nikolajev, 2003

– Both mandibles with distinct appendices, often nearly symmetric ( Figs. 30–32 , 37–39 )............................. 12

12 Distributed from banks of River Don ( Russia) to SE Europe (Balkans) and W Turkey.............. Lethrus (Scopoli, 1777)

– Distributed in S Kazakhstan, W Kirgizia, N Tajikistan S and SE Uzbekistan, Central and N Tajikistan, E Turkmenistan, N Afghanistan..................................................................... Autolethrus Semenov, 1892

Figures

FIGURES 36. Metafemur of Lethrus (Teratolethrus) baiocchii Hillert & Sechi, 2014 after Hillert & Sechi 2014).

FIGURES 24–29. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 24–26 L. (Hetroplistodus) bulbocerus bulbocerus Fischer von Waldheim, 1845 (24 frontal view, 25 lateral view, 26 dorsal view); 27–29 L.(Scelolethrus) sulcatus Kraatz, 1883 (27 fronta view l, 28 lateral view, 29 dorsal view).

FIGURES 9–12. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 9–10 L. (Ceratodirus) karelini Gebler, 1845 (9 frontal view, 10 lateral view); 11–12 L. (Ceratodirus) cephalotes Pallas, 1771 (11 frontal view, 12 lateral view).

FIGURES 13–17. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 13–14, 17 L. (Sinolethrus) serpentifer Semenov & Medvedev, 1935, (13 frontal view, 14 lateral view, 17 dorsal view); 15 L. (Ceratodirus) cephalotes Pallas, 1771 (dorsal view); 16 L. (Ceratodirus) karelini Gebler, 1845 (dorsal view).

FIGURES 18–23. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 18–20 L. (Furcilethrus) banghaasi Reitter, 1893 (18 frontal view, 19 lateral view, 20 dorsal view); 21–23 L. (Furcilethrus) tenuidens tenuidens Reitter, 1890 (21 frontal view, 22 lateral view, 23 dorsal view).

FIGURES 30–35. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 30–32 L. (Autolethrus) tshatkalensis Protzenko, 1965 (30 frontal view, 31 lateral view, 32 dorsal view); 33–35 L. (Teratolethrus) baiocchii Hillert & Sechi, 2014 (33 frontal view, 34 lateral view).

FIGURES 37–42. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically.37–39 L. (Lethrus) fallax Nikolajev, 1975 (37 view frontal, 38 lateral view, 39 dorsal view); 40–42 L.(Paralethrus) crassus Hillert, 2014 (40 frontal view, 41 lateral view, 42 dorsal view, after Hillert 2004).

FIGURES 43–48. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 43–45 L. (Paralethrus) bituberculatus macrodon Nikolajev, 1969 (43 frontal view, 44 lateral view, 45 dorsal view, after Hillert 2004); 46–48 L. (Abrognathus) tuberculifrons Ballion, 1871 (46 frontal view, 47 lateral view, 48 dorsal view).

FIGURES 49–54. Head of Lethrus species with mandibular appendix, keels and hornlike apophyses of mandibles (males), schematically. 49–51 L. (Mesolethrus) microbuccis Ballion, 1871 (49 frontal view, 50 lateral view, 51 dorsal view); 52–54 L. (Neolethrus) arcanus Medvedev, 1971 (52 frontal view, 53 lateral view, 54 dorsal view).

FIGURES 55–58. Labels, apical spurs and head of males of Lethrus species, schematically. 55 apical spur of front tibia of L. (Sinolethrus) serpentifer Semenov & Medvedev, 1935; 56 apical spur of front tibia of L. (Ceratodirus) karelini Gebler, 1845; 57 label of syntype of L. serpentifer; 58 label of lectotype of L. mediocris.

FIGURES 59–65. Lethrus (Sinolethrus) serpentifer Semenov & Medvedev, 1935 (Huang He, China). 59 male dorsal view; 60 male ventral view; 61 female dorsal view; 62 male, lateral view, right; 63 male, lateral view, left; 64 male, frontal view; 65 head with mentum of male, schematically.

FIGURES 1–4. Aedeagus, schematically. 1–2 L. (Ceratodirus) dostojewskii Semenov, 1899 (1 lateral view, 2 dorsal view); 3–4 L. (Sinolethrus) serpentifer Semenov & Medvedev, 1935 (3 lateral view, 4 dorsal view).

FIGURES 5–8. Aedeagus, schematically. 5 L. (Lethrus) ares Král, Rejsek & Schneider, 2001 (lateral view); 6 L. (Paralethrus) bituberculatus macrodon Nikolajev, 1969 (lateral view); 7 L. (Mesolethrus) inermis Reitter, 1897 (dorsal view); 8 L. (M.) elisae Nikolajev, 2001 (dorsal view).