Phanaeus balthasari Arnaud, 2001

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 : 454-455

Phanaeus balthasari Arnaud, 2001 , stat. rev.

( Figs 8–9 , 34 , 45 , 56 )

Phanaeus tridens balthasari Arnaud, 2001: 6 . Type locality: Guatemala, Huehuetenango.

Type material examined. GUATEMALA: H UEHUETENANGO: HOLOTYPE (originally designated by ARNAUD 2001, examined from photographs; Fig. 9 ) 1 ♂ ( PFASF). MEXICO: CH I APAS: P ARATYPE (examined from photographs): 1 ♂, 2 km S. Chicoasen ( CMNC).

Non-type material studied. GUATEMALA: H UEHUETENANGO: 1 ♂, Nenton,Camino Nenton-San José Chaquial ( UVGC); 1♀, Nenton, Finca El Carmen ( UVGC); 2♂♂ 1♀, Nenton, Finca El Zapote, Río Lagarteros ( VMPM); 1 ♀, Nenton, La Trinidad ( UVGC); 1 ♂, Nenton, San José Chaquial ( VMPM). MEXICO: CH I APAS: 1 ♀, Cerro Hueco ( GHVM); 1 ♂ 1 ♀, El Pozuelo ( GHVM); 2 ♂♂ 1 ♀, Las Delicias ( GHVM: 1 ♂ 1 ♀, VMPM: 1 ♂); 1 ♂ 3 ♀♀, Meseta de Copoya, Tuxtla Gutiérrez ( GHVM: 3 ♀♀, VMPM: 1 ♂); 2 ♂♂ 1 ♀, San Pedro ( VMPM); 2 ♀♀, Santa Rosa ( GHVM: 1 ♀, VMPM: 1 ♀); 3 ♂♂ 1 ♀, Vicente Guerrero ( VMPM); 2 ♀♀, Vicente Guerrero, San Fernando ( VMPM).

Diagnosis. Metallic green species with yellow-red sheen ( Figs 8–9 , 45 , 56 ). Sides of pronotal disc finely granulate and becoming granulorugose on raised outer margin of disc; disc weakly but coarsely rugose, more sparsely posteriorly ( Figs 8–9 , 45 ). Posteromedial process of pronotum produced into denticle, distinctly widened towards apex (not reaching anteromedial denticles), elongate, and apically bifurcated ( Figs 34 , 45 ). Anteromedial portion of pronotal disc with two denticles, distinctly separated by medial inconspicuous tubercle, this tubercle sometimes absent ( Fig. 45 ). Anterolateral margins of pronotal disc with distinctly developed ridge of tubercles ( Fig. 45 ). Posterolateral angles of pronotum less developed than posteromedial process of pronotum ( Figs 34 , 45 ). Elytral striae scabriculous, distinctly impressed and superficially punctate ( Figs 8–9 ). Elytral interstriae scabriculous, smooth, superficially punctate and convex ( Figs 8–9 ).

Variability. 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; pronotum with anteromedial black macula, and anteromedial trapezoidal carina followed by posterior concavity ( Fig. 56 ).

Comments. Specimens of this species were erroneously referred to as P. pseudofurcosus by EDMONDS (1994), who considered it a subspecies of P. tridens ( Figs 1–5 , 45 , 55 ). Additionally, specimens of the real P. pseudofurcosus ( Figs 22–23 , 39 , 51 , 62 ) were referred to as the “ Colima population” of P. tridens tridens ( EDMONDS 1994) . Subsequently, ARNAUD (2001) recognized the mistake by EDMONDS (1994) and described this taxon as a new subspecies, P. tridens balthasari . Finally, EDMONDS & ZÍDEK (2012) proposed P. t. balthasari as a junior subjective synonym of P. tridens , arguing that the entire P. tridens species group needed to be scrutinized.

The results of the present study demonstrate that P. balthasari merits full species status, because it is distinctly distinguished from P. tridens by a unique character combination: the posteromedial process of pronotum distinctly narrowed medially in posterior view ( Fig. 34 ; not narrowed in P. tridens , Fig. 32 ), ridge of tubercles of anterolateral margins of pronotal disc more raised in P. balthasari ( Fig. 45 ), posterolateral angles of pronotum parallel in P. balthasari ( Figs 8–9 ; subparallel in P. tridens , Figs 1–5 ) and pronotal disc more coarsely rugose in P. balthasari ( Figs 8–9 , 45 ). Putative hybrid specimens or populations between P. tridens and P. balthasari were not found, while P. tridens is restricted to north-central Veracruz and P. balthasari to Chiapas and Guatemala ( Fig. 64 ).

Distribution. From Chiapas, Mexico to Huehuetenango, Guatemala ( Fig. 64 ).

Figures

Figs 8–9.Phanaeus balthasari Arnaud,2001, stat.rev. 8 – male green phase;9 – holotype

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.

Figs 55–62. Pronotum of female. 55 – P. tridens Castelnau, 1840; 56 – P. balthasari Arnaud, 2001, stat. rev.; 57 – P. daphnis Harold, 1863; 58 – P. substriolatus Balthasar, 1939, stat. rev. (dark blue-black phase); 59 – P.herbeus Bates, 1887, stat. rev. (green phase); 60 – P. nimrod Harold, 1863 (blue-green phase); 61 – P. furiosus Bates, 1887 (dark blue phase); 62 – P. pseudofurcosus Balthasar, 1939, stat. rev. Scale bar = 1.0 mm.

Figs 1–5. Phanaeus tridens Castelnau, 1840. 1 – male green phase; 2 – male green-red phase; 3 – neotype and labels, present designation (by Christophe Rivier, MNHN); 4 – P. frankenbergeri junior subjective synonymy, holotype and labels (by Jiří Hájek, NMPC); 5 – Eൽආඈඇൽඌ’ (1994) neotype of P. tridens and labels (by Simon Hinkley, NMVA). Scale bar = 1.0 mm.

Figs 22–23.Phanaeus pseudofurcosus Balthasar, 1939, stat.rev.22 – male green phase;23 – holotype and labels (by Jiří Hájek,NMPC).Scale bar = 1.0 mm.

Fig. 64. Predicted distribution of P. tridens Castelnau, 1840, P. moroni Arnaud, 2001 and P. balthasari Arnaud, 2001. The distribution of P. coeruleus Bates, 1887 was not modelled because it is only known from a single locality that needs confirmation.