Phanaeus eximius Bates, 1887

Moctezuma, Victor, Halffter, Gonzalo & Lizardo, Viridiana, 2021, The Phanaeus tridens species group (Coleoptera: Scarabaeoidea): a dung beetle group with genital morphological stasis but a changing ecological niche, Acta Entomologica Musei Nationalis Pragae 61 (2), pp. 447-482 : 471

Phanaeus eximius Bates, 1887

( Figs 29–31 , 42 , 54 )

Phanaeus eximius Bates, 1887: 62 . Type locality: Guatemala.

Type material examined. L ECTOTYPE (designated by EDMONDS 1994, examined from photographs; Fig. 31 ): ♂, without specific locality ( BMNH: NHMUK 013903535).

Non-type material examined. GUATEMALA: W I THOUT SPEC I F I C LOCAL I TY: 1 ♀ ( GHVM). NICARAGUA: U NKNOWN LOCAL I TY: 1 ♂ ( GHVM).

Diagnosis. Metallic green ( Fig. 30–31 ), deep blue-green ( Fig. 29 ), dark blue ( Fig. 54 ), green-yellow or red. Sides of pronotal disc finely granulate ( Figs 29, 31 , 54 ). Pronotal disc coarsely granulorugose ( Figs 29, 31 , 54 ). Posteromedial process of pronotum produced into triangular denticle, widened laterally, not bifurcated apically ( Figs 42 , 54 ). Anteromedial portion of pronotal disc with two strongly developed denticles ( Fig. 54 ). Anterolateral margins of pronotal disc with inconspicuous line of tubercles ( Fig. 54 ). Posterolateral angles of pronotum more developed than posteromedial process ( Figs 42 , 54 ). Elytral striae scabriculous, coarsely impressed, coarsely punctate ( Figs 29–31 ). Elytral interstriae highly vermiculate, superficially punctate, convex ( Figs 29–31 ).

Variation. Minor male. Similar to major males, except for reduction of secondary sexual characters (i.e., cephalic horn, pronotal processes and posterolateral angles). Female. Similar to male, except for head showing trituberculate carina; pronotal sculpture granulate to superficially punctate, smooth or rugose posteriorly; pronotum with anteromedial black macula, and anteromedial carina followed by posterior concavity ( Fig. 30 ).

Comments. Apparently, this species is well defined and is not involved in taxonomical controversies ( EDMONDS 1994, ARNAUD 2002, EDMONDS & ZÍDEK 2012). The only variation that was reported by previous studies is its several chromatic phases ( Figs 29–31 , 54 ). All specimens here revised show the distinctly vermiculate elytral striae ( Figs 29–31 ). Nevertheless, further studies are needed to understand the intraspecific variation in P. eximius since a limited number of specimens was available for our work.

Distribution. Guatemala, El Salvador, Nicaragua, Costa Rica and probably Honduras. Following P. furiosus ( Fig. 66 ), this is the second most widely distributed species within the P. tridens species group ( Fig. 68 ).

Figures

Figs 29–31. Phanaeus eximius Bates, 1887. 29 – male blue phase; 30 – female green phase (typical); 31 – lectotype and labels (by Keita Matsumoto, BMNH). Scale bar = 1.0 mm.

Figs 32–42. Posterior view of pronotum of major male. 32 – P. tridens Castelnau, 1840; 33 – P. moroni Arnaud, 2001, stat. rev.; 34 – P. bal- thasari Arnaud, 2001, stat. rev.; 35 – P. daphnis Harold, 1863; 36 – P. substriolatus Balthasar, 1939, stat. rev.; 37 – P.herbeus Bates, 1887, stat. rev.; 38 – P.furiosus Bates, 1887; 39 – P.pseudofurcosus Balthasar, 1939, stat. rev.; 40 – P. nimrod Harold, 1863; 41 – P. victoriae Moctezuma sp. nov.; 42 – P. eximius Bates, 1887. Scale bar = 1.0 mm.

Figs 43–54. Lateral view of pronotum of major male. 43 – P. tridens Castelnau, 1840; 44 – P. moroni Arnaud, 2001, stat. rev.; 45 – P. balthasari Arnaud, 2001; 46 – P. daphnis Harold, 1863; 47 – P. coeruleus Bates, 1887, stat. rev. (holotype, by Keita Matsumoto, BMNH); 48 – P. substriolatus Balthasar, 1939, stat. rev.; 49 – P. herbeus Bates, 1887, stat. rev. (green-red phase); 50 – P. furiosus Bates, 1887 (green phase); 51 – P. pseudofurcosus Balthasar, 1939, stat. rev.; 52 – P. nimrod Harold, 1863; 53 – P. victoriae Moctezuma sp. nov. (holotype); 54 – P. eximius Bates, 1887. Scale bar = 1.0 mm.

Fig. 66. Predicted distribution of P. furiosus Bates, 1887 and P. pseudofurcosus Balthasar, 1939.

Fig. 68. Predicted distribution of P. eximius Bates, 1887.