Liogenys, Guerin-Meneville, 1831

Cherman, Mariana A., Basílio, Daniel S., Mise, Kleber M., Frisch, Johannes, Smith, Andrew B. T. & Almeida, Lúcia M., 2020, Liogenys Guérin-Méneville, 1831 (Coleoptera: Scarabaeidae: Melolonthinae) from the southern South American Transition Zone and boundaries: taxonomic overview with four new species, Zootaxa 4896 (1), pp. 46-84 : 48-49

Identification key to Liogenys from the southern South American Transition Zone and boundaries *

*Note on dimorphism: Males have protarsi and mesotarsi flat (wide or not) and females have all tarsi cylindrical.

1. Length of antennal club two times longer than the funicle or almost so ( Fig. 10D ); head, pronotum, and scutellum dark purplish brown, elytra yellow ( Fig. 10A ); elytra glabrous; metatibia with inner margin not carinate in both sexes........................................................................................... Liogenys xanthocera Harold, 1869

- Length of antennal club as long as or slightly longer than funicle; head, pronotum, scutellum, and elytra unicolored, yellow or light brown, elytra sometimes slightly lighter in color than pronotum; elytra glabrous or with bristles; male with metatibia weakly or strongly carinate toward apex....................................................................2

2. Head more coarsely punctate than pronotum ( Fig. 8B ); pronotum wider than elytra at its humeral callus; galea with a single, long, hook-like tooth ( Fig. 13G ); antenna with 9 antennomeres; elytra with bristles............................................................................................... Liogenys maxillaricuspis Cherman , new species

- Head as punctate as or less coarsely punctate than pronotum; pronotum as wide as or slightly narrower than elytra at its humeral callus; galea with four or five teeth ( Fig. 13E ), the superior tooth slightly larger than the other teeth; antenna with 9–10 antennomeres; elytra glabrous or with bristles................................................................... 3

3. Pygidium longer than wide ( Fig. 1E ) and always with bristles.................................................. 4

- Pygidium as wide as or wider than long, glabrous or with bristles................................................6

4. Antenna with 10 antennomeres; body length up to 8.5 mm; clypeus emargination in general deep, eventually shallow, narrower than the distance between eyes in both sexes; protibia with three teeth in both sexes; males with inner margin of metatibia carinate towards apex or not................................................................................ 5

- Antenna with 9 antennomeres; body length more than 8.5 mm; clypeus emargination noticeably shallow, females with emargination narrower than the distance between eyes, males with emargination as wide as the distance between eyes ( Fig. 4F ); protibia in males with two teeth and in females with three teeth; males with inner margin of metatibia carinate......................................................................................... Liogenys flavida Moser, 1918

5. Head as wide as or narrower than posterior margin of pronotum ( Fig. 9C ); clypeus as long as frons; vertex finely to coarsely punctate; males with inner margin of metatibia carinate straight towards apex; protarsi noticeably enlarged, protarsomere II wider than long.............................................................. Liogenys rufoflava Moser, 1918

- Head distinctly wider than posterior margin of pronotum ( Fig. 1B ); clypeus noticeably shorter than frons; vertex smooth ( Fig. 1B ); males with inner margin of metatibia not carinate; protarsi slightly enlarged, protarsomere II longer than wide..................................................................... Liogenys brachyclypeata Cherman , new species

6. Elytra and pygidium glabrous; males with inner margin of metatibia carinate towards apex; protarsomere II noticeably wider than long; apex of parameres lanceolate in a single plane ( Figs. 3F , 9F )................... Liogenys flaveola Moser, 1924

- Elytra and pygidium with bristles; males with inner margin of metatibia weakly or not carinate, if carinate, carina never reaching the apex; protarsomere II as long as or longer than wide; apex of parameres lanceolate or not, if lanceolate, never in a single plane ( Figs. 2F , 5F , 7F )................................................................................. 7

7. Elytra dull yellow, never pruinose or if so, not uniformly, pronotum unicolored with elytra; males with metatibial transverse carinae incomplete ( Fig. 6E ).............................................................................8

- Elytra light brown, uniformly pruinose, pronotum dark brown, darker than elytra; metatibia with one or two transverse carinae complete in both sexes ( Fig. 5D .......................................................................... 9

8. Clypeal lateral margin with a blunt projection ( Fig. 2D ), convex; clypeal teeth well developed in both sexes, teeth acute; protibia with three teeth in both sexes; males with protarsomere and mesotarsomere II equally wide; spurs of metatibia uneven in shape ( Fig. 2E )................................................................ Liogenys calcarata Frey, 1970

- Clypeal lateral margin not produced, straight or concave, clypeal teeth well developed only in males, teeth broad; protibia in males with two teeth and in females with three teeth; males with protarsomere II noticeably wider than mesotarsomere II; spurs of metatibia even in shape ( Fig. 6C ).................................. Liogenys lucialmeidae Cherman , new species

9. Elytra shiny or semiopaque, never pruinose; ventrites and pygidium with few bristles; males with two protibial teeth and females with three teeth.......................................................... Liogenys kuntzeni Moser, 1921

- Elytra opaque, noticeably pruinose ( Fig. 7E ); ventrites and pygidium with thick, scale-like bristles; both sexes with three protibial teeth........................................................ .. Liogenys martinezi Cherman , new species

Figures

FIGURE 1. Liogenys brachyclypeata Cherman, new species, male holotype views: A) dorsal, B) clypeus and pronotum, C) frontal, D) lateral, E) pygidium, and parameres views: F) dorsal, G) lateral.

FIGURE 2. Liogenys calcarata Frey, 1970, male holotype views: A) dorsal, B) clypeus and pronotum, C) pygidium, D) lateral, E) metatibia, black arrow indicating short, modified spur, and parameres views: F) dorsal, G) lateral.

FIGURE 3. Liogenys flaveola Moser, 1924, male holotype views: A) dorsal, B) clypeus and pronotum, C) pygidium, D) lateral, E) metatibia, and parameres views: F) dorsal, G) lateral.

FIGURE 4. Liogenys flavida Moser, 1918, male lectotype views: A) dorsal, B) labels, C) lateral, D) frontal, E) pygidium, F) clypeus, and parameres views: G) dorsal, H) lateral.

FIGURE 5. Liogenys kuntzeni Moser, 1921, male holotype views:A) dorsal, B) clypeus and pronotum, C) pygidium, D) lateral, E) meso- and metatibia, and parameres views: F) dorsal, G) lateral.

FIGURE 6. Liogenys lucialmeidae Cherman, new species, male holotype views: A) dorsal, B) clypeus and pronotum, C) pygidium, D) lateral, E) meso- and metatibiae, and parameres views: F) dorsal, G) dorsolateral, H) lateral.

FIGURE 7. Liogenys martinezi Cherman, new species, male holotype views: A) dorsal, B) clypeus and pronotum, C) pygidium, D) lateral, E) detail of pruinose elytron, and parameres views: F) dorsal, G) lateral.

FIGURE 8. Liogenys maxillaricuspis Cherman, new species, male holotype views: A) dorsal, B) clypeus and pronotum, C) variation of clypeus, D) lateral, E) pygidium, and parameres views: F) dorsal, G) dorsolateral, H) arrows indicating variations in shape, I) lateral.

FIGURE 9. Liogenys rufoflava Moser, 1918, male lectotype views: A) dorsal, B) labels, C) clypeus and pronotum, D) lateral, E) pygidium, and parameres views: F) dorsal, G) lateral.

FIGURE 10. Liogenys xanthocera Harold, 1869, male lectotype views: A) dorsal, B) labels, C) clypeus and pronotum, D) lateral, E) pygidium, and parameres views: F) dorsal, G) lateral.

FIGURE 13. Liogenys maxillaricuspis Cherman, new species: A) head in ventral view, C) labium, G) right maxilla; L. brachyclypeata Cherman, new species: B) head in ventral view, D) labium; L. calcarata Frey, 1970: E) left maxilla; L. xanthocera Harold, 1869: F) right maxilla. Legends: A, B) CLP: clypeus, LBM: labium, LBR: labrum, MXL: maxilla, MXLP: maxillary palp. C, D) LGL: ligula, LPLP: labial palp, MTM: mentum, PMTM: postmentum.