DIPLOTAXINI

Cherman, Mariana A., Basílio, Daniel S., Clarkson, Bruno, Agostinis, André O., Smith, Andrew B. T., Vaz-De-Mello, Fernando Z. & Almeida, Lúcia M., 2024, New and revised taxa of Neotropical Diplotaxini (Coleoptera: Melolonthidae): do they change the existing relationships? Revisiting systematics with morphological and molecular data, Zoological Journal of the Linnean Society 201 (1), pp. 98-135 : 108

IDENTIFICATION KEY TO NEW WORLD DIPLOTAXINI [modified from Cherman et al. (2017)]

1. Division between clypeus and frons distinct [see Cherman et al. (2016) for more details] ( Fig. 4A ); sutural ridge of elytra not narrowed posteriad ( Fig. 6A ); galea of maxilla curved, not forming an angle at the apex of its external margin ( Fig. 4D . ............................................................................................................................................................................................................................2

-. Division between clypeus and frons indistinct; sutural ridge of elytra strongly narrowed posteriad; galea of maxilla straight, forming an angle at the apex of its external margin..................................................................................................................................3

2. Pronotal anterior corners reduced, evenly continuous with hypomeron ( Fig. 4B ); propygidium entirely exposed; pygidium subquadrate; elytra flattened, apex of sutural ridge of elytra rounded ( Fig. 14C ) ...................................................... Homalochilus

-. Pronotal anterior corners distinctly elevated, hypomeron not continuous with dorsal surface; pygidium suboval; propygidium mostly hidden by elytra; elytra flattened or convex, apex of sutural ridge of elytra angled ( Fig. 14A ) .................. ............................................................................................................................................................................................................ Diplotaxis

3. Frons and clypeus coplanar; concavity on disc of mentum and arched transverse carina absent ( Fig. 15A ) ................. Pacuvia

-. Frons and clypeus not coplanar, broad concavity on disc of mentum limited by arched transverse carina ( Fig. 15B ).............4

4. Inner margin of both eyes more-or-less convergent ( Fig. 15D, E, G, H ): anterior margin of clypeus widely rounded ( Fig. 15D ) or subemarginate ( Fig. 15E ), never forming tooth-like projections; frons and clypeus medially flattened, not concave ............................................................................................................................................................................................................................5

-. Inner margin of both eyes parallel ( Fig. 15C, F ); anterior margin of clypeus emarginate, forming tooth-like projections ( Fig. 15C ); frons and clypeus medially flattened or concave ............................................................................................................. Liogenys

5. Clypeus rounded, sometimes anterior margin narrowly emarginate ( Fig. 15D ); apex of both mandibles forming obtuse angle, seen in frontal view of head ( Fig. 13B ); apex of sutural ridge of elytra rounded or subangulate ( Fig. 14B ), subapical callus of elytra distinct on apex, more-or-less defined ( Fig. 7I )........................................................................................ Pachrodema

-. Clypeus trapezoidal, subemarginate ( Figs. 8B , 9A , 10B , 15E ); apex of both mandibles forming acute angle, seen in frontal view of head ( Fig. 13A ); apex of sutural ridge of elytra sharp, right or obtuse-angulate ( Fig. 14F ), subapical callus of elytra absent ( Fig. 9C ) ............................................................................................................................................................................ Careocallus

Figures

Figure 4. Diagnostic features and transformations that support Homalochilus. Head in dorsal view (A), head and anterior portion of prothorax in dorsolateral view (B); head in frontal view (C); maxilla (D); labium (E); elytra, white square indicates erect setae (F); head, pronotum, scutellum and proleg (G), thoracic and abdominal ventrites, white lines indicate size of ventrites (H). White arrows in each figure indicate transformations and/or detailed features.

Figure 6. Homalochilus nigripennis. Male holotype habitus (A); head and pronotum (B); lateral (C); posterior (D) views; metatibial apex (E); parameres in dorsal (F) and lateral (G) views. White arrow indicates the longest spur.

Figure 7. Liogenys niger (Blanchard) comb. nov.. Male neotype habitus (A), labels (E), and complete series at MLUH (D); female lectotype (B) and labels (F); non-uniform body colour variation (C); male in lateral (G) and posterior (I) views; detail of ventrites II and II with medial tubercle (H); parameres in dorsal (J) and lateral (K) views.

Figure 8. Careocallus tehuelche. Male holotype habitus (A), head and pronotum (B), lateral (C), metatibia (D), posterior (E), and parameres in dorsal (F) and lateral (G) views.

Figure 9. Careocallus tehuelche. Female paratype habitus (A); lateral (B) and posterior (C) views; protarsal claw of female (D) and male (E).

Figure 10. Careocallus densicollis. Male holotype habitus (A); head and pronotum (B); lateral (C) and posterior (F) views; metatibia (D); protibial claw (E); parameres in dorsal (G) and lateral (H) views.

Figure 13. Head in frontoventral view (A–C) and left mandible (D–G) of some Neotropical Diplotaxini. Careocallus tehuelche (A, D); Pachrodema sp. (B–G); Liogenys suturalis (Blanchard) (C, E); Homalochilus punctatostriatus (F).

Figure 14. Posterior margin of elytra, variation in apex of sutural ridge among Diplotaxini.Apex angulate (A, F); apex subangulate (E) or rounded (B–D). Diplotaxis tristis Kirby (A); Pachrodema castanea Blanchard (B); Homalochilus punctatostriatus (C); Pacuvia philippiana Gutiérrez (D); Liogenys suturalis (E); Careocallus tehuelche (F).

Figure 15. Mentum disc, arched transverse carina and concavity absent (A) or present (B); inner margins of both eyes parallel (C, F) or with degrees of convergence (D–E, G–H). Pacuvia castanea Curtis (A); Liogenys bidenticeps Moser (B); L. fusca Blanchard (C, F); Pachrodema castanea (D, G); Careocallus densicollis (E, H).