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: HඎൾHඎൾඍൾඇൺඇGඈ: Hඈඅඈඍඒ- ඉൾ (originally designated by Aඋඇൺඎൽ 2001, examined from photographs; Fig. 9) 1 J ( PFASF). MEXICO: CH ංൺඉൺඌ: Pൺඋൺඍඒඉൾ (examined from photographs): 1 J, 2 km S. Chicoasen ( CMNC).

Non-type material studied. GUATEMALA: HඎൾHඎൾඍൾඇൺඇGඈ: 1 J, Nenton,Camino Nenton-San José Chaquial ( UVGC); 1♀, Nenton, Finca El Carmen ( UVGC); 2JJ 1♀, Nenton, Finca El Zapote, Río Lagarteros ( VMPM); 1 ♀, Nenton, La Trinidad ( UVGC); 1 J, Nenton, San José Chaquial ( VMPM). MEXICO: CH ංൺඉൺඌ: 1 ♀, Cerro Hueco ( GHVM); 1 J 1 ♀, El Pozuelo ( GHVM); 2 JJ 1 ♀, Las Delicias ( GHVM: 1 J 1 ♀, VMPM: 1 J); 1 J 3 ♀♀, Meseta de Copoya, Tuxtla Gutiérrez ( GHVM: 3 ♀♀, VMPM: 1 J); 2 JJ 1 ♀, San Pedro ( VMPM); 2 ♀♀, Santa Rosa ( GHVM: 1 ♀, VMPM: 1 ♀); 3 JJ 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 Eൽආඈඇൽඌ (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 (Eൽආඈඇൽඌ 1994). Subsequently, Aඋඇൺඎൽ (2001) recognized the mistake by Eൽආඈඇൽඌ (1994) and described this taxon as a new subspecies, P. tridens balthasari . Finally, Eൽආඈඇൽඌ & ZටൽൾK (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).