Liogenys, Guerin-Meneville, 1831

Cherman, Mariana Alejandra, Basílio, Daniel Silva, Mise, Kleber Makoto, Frisch, Johannes & Almeida, Lúcia Massutti De, 2021, Liogenys Guérin-Méneville, 1831 (Coleoptera: Scarabaeidae: Melolonthinae Diplotaxini) from the Chacoan Province and its boundaries: taxonomic overview with four new species, Zootaxa 4938 (1), pp. 1-59 : 3-4

Identification key to Liogenys species from the Chacoan province and its boundaries

1. Antenna with 10 antennomeres; clypeal emargination wide or narrow; outer sides of anterior clypeal teeth parallel ( Figs. 2B , 3B ) or following the lateral margin of clypeus ( Figs. 9B , 21B ).................................................. 2

- Antenna with 9 antennomeres; clypeal emargination narrow and semicircular ( Fig. 12E ); outer sides of anterior clypeal teeth following the lateral margin of clypeus.......................................... Liogenys mendozana Moser, 1918

2. Clypeal teeth very short ( Fig. 4B ), outer sides of teeth not forming an angle with the lateral margin of clypeus; lateral margin convex or straight, not produced......................................................................... 3

- Clypeal teeth long or short ( Figs. 2B , 8B ), outer sides of teeth forming an angle with the lateral margin of clypeus, lateral margin convex and sometimes strongly produced ( Fig. 6B )....................................................... 8

3. Pronotal disc densely punctate ( Fig. 3B )................................................................... 4

- Pronotal disc sparsely punctate ( Figs. 2B , 10C ).............................................................. 6

4. Pronotum and elytra glabrous; punctures of pronotum very fine and dense ( Fig. 4B ); pygidium with dense scales ( Fig. 4D ), scales sparse only at the apex...................................................... Liogenys densata Frey, 1969

- Pronotum and elytra setose; punctures of pronotum coarse and dense ( Fig. 3B ); pygidium with sparse bristles and scales... 5

5. Clypeal emargination semicircular, narrow, lateral margin of clypeus never produced; in males inner margin of metatibia concave subapically ( Fig. 16F )................................................ Liogenys opacicollis Fairmaire, 1892

- Clypeal emargination rounded, wide, lateral margin of clypeus concave, produced in most of the cases, forming a blunt projection ( Fig. 3B ); in males inner margin of metatibia convex subapically ( Fig. 3F ).......... Liogenys cribricollis Moser, 1921

6. Lateral margin of clypeus concave, in males tarsomeres almost equal in width in all legs, cylindrical ( Fig. 9E )............................................................................... Liogenys isotarsis Cherman , new species

- Lateral margin of clypeus straight ( Fig. 21B ), in males protarsomeres and mesotarsomeres enlarged.................... 7

7. Elytra setose, shiny; body length less than 8 mm ............................. Liogenys truncata Cherman , new species

- Elytra glabrous, semiopaque; body length 9–10 mm .................................. Liogenys rectangula Frey, 1969

8. Pronotum roughly punctate; lateral sides of abdomen, propygidium, and pygidium covered by wide scales ( Fig. 20C )................................................................................. Liogenys rugosicollis Frey, 1969

- Pronotum somewhat coarsely punctate; sides of abdomen, propygidium, and pygidium with bristles ( Fig. 10D )........... 9

9. Width of clypeal teeth combined three or more times longer than the length of one tooth ( Figs. 14B , 18B ).............. 10

- Width of clypeal teeth combined less than three times longer than the length of one tooth ( Figs. 6B , 8B )............... 17

10. Epipleuron of elytra uniformly clothed by fringed-like, long, erect bristles ( Fig. 18A, E ); legs with tarsomere II twice as long as tarsomere I, or almost so, especially in male....................................... Liogenys parallela Frey, 1965

- Epipleuron of elytra with sparse, short bristles; legs with tarsomere II less than twice as long as tarsomere I............. 11

11. Pygidium subquadrate ( Fig. 14D ), apex angulate, punctures very coarse; clypeal emargination deeper than the outer margin of anterior teeth ( Fig. 14B )...................................................... Liogenys nigrofusca Moser, 1918

- Pygidium trapezoidal ( Figs. 2 D–E; 5G–H; 15G), apex subangulate or rounded; clypeal emargination shallower than the outer margin of anterior teeth ( Fig. 10C )....................................................................... 12

12. Lateral margin of clypeus weakly produced, outer sides of anterior teeth obtuse or subparallel, without angle among anterior teeth and lateral margin of clypeus ( Fig. 15E ).............................................................. 13

- Lateral margin of clypeus strongly produced, outer sides of anterior teeth almost parallel, right or acute angle between anterior and lateral teeth ( Fig. 10C )............................................................................. 14

13. Propygidium scaly; pygidium with erect and thick setae............................ Liogenys obscura Blanchard, 1851

- Propygidium with sparse bristles; pygidium with decumbent bristles.................... Liogenys cartwrighti Frey, 1969

14. Pygidium glabrous, or with few bristles on apex; distance between teeth of each tarsal claw as long as the length of superior tooth.............................................................................................. 15

- Pygidium setose, distance between teeth of each tarsal claw shorter than the length of inferior tooth................... 16

15. Body shiny, head and pronotum unicolored brown or dark brown in both sexes; clypeal emargination narrow, without clear sexual dimorphism in the clypeal margin; males with protarsomere II longer than wide ( Fig. 5J )............................................................................................... Liogenys denticeps Blanchard, 1851

- Body opaque, head and pronotum dull yellow unicolored in males, not unicolored in females, head dark brown or black; clypeal emargination very wide, in females emargination as wide as one half the distance between eyes, in males wider; males with protarsomere II as long as wide or wider than long ( Fig. 10D )........................ Liogenys pallens Blanchard, 1851

16. Metafemur glabrous, row of bristles along its margins; males with parameres angulate at the midline, without subapical constriction ( Fig. 11 )............................................................. Liogenys latitarsis Moser, 1918

- Metafemur setose throughout; males with parameres globose at the midline, with subapical constriction ( Fig. 22E )....................................................................................... Liogenys vicina Frey, 1969

17. Clypeal emargination angulate ( Fig. 8B ); fovea of distal maxillary palp occupying the entire dorsal surface, almost reaching the apex ( Fig. 8C )......................................................... Liogenys foveata Cherman new species

- Clypeal emargination rounded; fovea of distal maxillary palp extending past the midline but not reaching the apex....... 18

18. Base of pygidium less than twice as wide as the apex ( Fig. 7E ); in males, the three pairs of tarsi equally enlarged...................................................................................... Liogenys tarsalis Moser, 1921

- Base of pygidium twice as wide as the apex ( Figs. 7F , 13D ); in males, protarsi and mesotarsi wider than the metatarsi.... 19

19. Base of metacoxae and trochanter setose ( Fig. 13E ); in males, parameres glabrous ( Fig. 13F ).......................................................................................... Liogenys neoforcipata Cherman , new species

- Base of metacoxae and trochanter almost glabrous ( Fig. 6D ); in males, parameres setose ( Fig. 6F )... Liogenys forcipata Frey

Figures

FIGURE 2. Liogenys cartwrighti Frey, 1969 male views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, E) female pygidium, and parameres in views: F) dorsal, and G) lateral.

FIGURE 3. Liogenys cribricollis Moser, 1921 male lectotype views: A) dorsal, B) head and pronotum, C) variation in shape of clypeus, D) labels, E) lateral, F) mesotibia and metatibia, G) mesotarsomere I, white arrow indicates ventral side modified, H) pygidium, I) female pygidium, J) apex of metatibia, white arrow indicates projection below the spurs, and the parameres in views: K) dorsal and L) lateral.

FIGURE 4. Liogenys densata Frey, 1969 male views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, E) metatibia, and parameres in views: F) dorsal, and G) lateral.

FIGURE 5. Liogenys denticeps Blanchard, 1851 female lectotype views: C) dorsal, F) labels, I) pygidium; L. denticulata Moser, 1918 male lectotype: A) dorsal, D) labels, G) pygidium, J) lateral, and parameres views: K) dorsal and L) lateral; L. denticulata female paralectotype views: B) dorsal, E) labels.

FIGURE 6. Liogenys forcipata Frey, 1970 male views: A) dorsal, B) head and pronotum, C) lateral, D) base of metatibia, white arrow indicates basal apophysis and metatrochanter, E) pygidium, and parameres in views: F) dorsal and G) lateral.

FIGURE 7. Liogenys tarsalis Moser, 1921 female views: A) dorsal, C) head and pronotum, E) pygidium; compared with L. forcipata Frey, 1970 female views: B) dorsal, D) head and pronotum, F) pygidium.

FIGURE 8. Liogenys foveata Cherman, new species, male holotype views: A) dorsal, B) head and pronotum, C) distal maxillary palp, D) lateral, E) mesotibia and metatibia, F) pygidium, and parameres in views: G) dorsal, and H) lateral.

FIGURE 9. Liogenys isotarsis Cherman, new species, male holotype views: A) dorsal, B) head and pronotum, C) pygidium, D) lateral, E) metatibia and tarsi, black rows indicate not enlarged tarsi of all legs, and parameres in views: F) dorsal, and G) lateral.

FIGURE 10. Liogenys latitarsis Moser, 1918 male lectotype views: A) dorsal, B) labels, C) head and pronotum, D) lateral, E) pygidium, and parameres in views: F) dorsal and G) lateral.

FIGURE 11. Liogenys latitarsis Moser, 1918 intraspecific variations in shape of parameres, views: A–E) dorsal, F–J) dorsolateral.

FIGURE 12. Liogenys mendozana Moser, 1918 male lectotype views: A) dorsal, C) labels, E) head and pronotum, F) lateral, G) pygidium, H) female pygidium, and parameres in views: I) dorsal and J) lateral; L. mendozanus incisus Frey, 1969 female neotype views: B) dorsal, D) labels.

FIGURE 13. Liogenys neoforcipata Cherman, new species, male holotype views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, E) base of metatibia, white arrow indicates basal apophysis and metatrochanter, and parameres in views: F) dorsal, and G) lateral.

FIGURE 14. Liogenys nigrofusca Moser, 1918 male views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, and parameres in views: E) dorsal, and F) lateral.

FIGURE 15. Liogenys obscura Blanchard, 1851 female lectotype views: A) dorsal, C) labels; L. bruchi Moser, 1921 male lectotype views: B) dorsal, D) labels, E) head and pronotum, F) lateral, G) pygidium, and parameres in views: H) dorsal, I) dorsolateral and J) lateral.

FIGURE 16. Liogenys opacicollis Fairmaire, 1892 female lectotype views: A) dorsal, C) labels; L. densicollis Moser, 1921 male lectotype views: B) dorsal, D) labels, E) lateral, F) mesotibia and metatibia, white arrow indicates shape of metatibial margin, G) mesotarsomere I, arrow indicates modified inner margin and H) its variation, I) apex of metatibia, white arrow indicates projection below the spurs, J) pygidium, and parameres in views: K) dorsal and L) lateral.

FIGURE 18. Liogenys parallela Frey, 1965 male views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, E) female pygidium, and parameres in views: F) dorsal, G) dorsolateral, and H) lateral.

FIGURE 20. Liogenys rugosicollis Frey, 1969 male views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, and parameres in views: E) dorsal, and F) lateral.

FIGURE 21. Liogenys truncata Cherman, new species, male holotype views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, and parameres in views: E) dorsal, and F) lateral.

FIGURE 22. Liogenys vicina Frey, 1969 male holotype views: A) dorsal, B) head and pronotum, C) lateral, D) pygidium, and parameres in views: E) dorsal, F) dorsolateral, and G) lateral.