Key to the species of the Phanaeus tridens species group

1 Elytral interstriae flat (Figs 11–15). ........................ 2

– Elytral interstriae distinctly convex (Figs 1–9, 16–17, 19–31). ..................................................................... 4

2 Posteromedial process of pronotum produced into slender and elongate denticle (Figs 36, 48). Posteromedial process and posterolateral angles of pronotum conical, similar in size (Figs 36, 48). Elytral interstriae superficially impressed or partially erased (Figs 14–15). Southern Puebla to northern Oaxaca and central Guerrero (Fig. 65). ............................................... ................................ P. substriolatus Balthasar, 1939

– Posteromedial process of pronotum produced into small denticle (Figs 35, 46–47). Posterolateral angles much longer than posteromedial process of pronotum (Figs 35, 46–47). Elytral interstriae distinctly impressed (Figs 10–13). .................................................... 3

3 Metallic green, rarely deep-blue with green sheen (Figs 10–12). Elytral interstriae I, III, V, VI and VII frequently roughened (Figs 10–12). Estado de México, Guerrero, Morelos, Puebla, Oaxaca (Fig. 65). ..... ............................................. P. daphnis Harold, 1863

– Dark blue with metallic turquoise sheen (Fig. 13). Elytral interstriae I, III and V smooth; VI and VII lightly roughened (Figs 10–12). Puebla. .................... ............................................ P. coeruleus Bates, 1887

4 Posteromedial process of pronotum strongly widened as triangular ridge, not bifurcated apically, much longer than posterolateral angles (Figs 40, 52). Clypeal process (viewed from front) narrow, acute, usually much longer than wide at base (Figs 24–26). Central Valleys of Oaxaca to central Guerrero (Fig. 67). ....... .............................................. P. nimrod Harold, 1863

– Posteromedial process of pronotum spine-like; triangular, not bifurcated apically, but shorter than posterolateral angles; or triangular, much longer than posterolateral angles but bifurcated apically (Figs 32–34, 37–39, 41–42, 43–45, 49–51, 53–54). Clypeal process variable, but almost always broader than long (Figs 1–9, 16–17, 19–23, 27–31). ..................................... 5

5 Elytral striae coarsely impressed and coarsely punctate with transverse punctures irregular in size (Figs 27–31). ..................................................................... 6

– Elytral striae distinctly impressed and superficially punctate with almost effaced punctures (Figs 1–9, 16–17, 19–23). ......................................................... 7

6 Bright metallic red with green-yellow sheen (Figs 27–28, 53). Posterolateral angles of pronotum longer than posteromedial process (Figs 41, 53). Elytral interstriae distinctly scabriculous (Figs 27–28). Eastern Oaxaca and probably western Chiapas (Fig. 67). ....... ................................ P. victoriae Moctezuma sp. nov.

– Metallic green, blue-green, dark blue, green-yellow, or red (Figs 29–31, 54). Posterolateral angles of pronotum shorter than posteromedial process of pronotum (Figs 42, 54). Elytral interstriae distinctly vermiculate (Figs 29–31). Guatemala to Costa Rica (Fig. 68). ........................................ P. eximius Bates, 1887

7 Posteromedial process of pronotum produced into thick, short, projection emarginate apically (Figs 38–39, 50–51). Posterolateral portions of pronotum not sharply upturned nor produced into strong conical teeth (Figs 38–39, 50–51). ....................................... 8

– Posteromedial process of pronotum bifurcated apically, usually produced into elongate spine-like projection or triangular denticle (Figs 18, 32–34, 37). Posterolateral portions of pronotum sharply upturned or produced into slender, elongate, conical teeth (Figs 18,32 –34,37)......................................................... 9

8 Metallic green (Figs 19, 21, 50), dark blue (Fig. 61) or garnet-red (Fig. 20), occasionally green with bright red sheen. Pronotal disc strongly concave, rugose to granulorugose (Figs 19–21, 50). Anterolateral margins of pronotum with variable number of short tubercles; tubercles sometime carinate or rounded (Fig. 50). Posteromedial process of pronotum thick basally, strongly emarginate apically (Figs 38, 50). Central Jalisco to Sonora (Fig. 66). ..... P. furiosus Bates, 1887

– Metallic bright green (Figs 22–23), occasionally with red sheen (Fig. 51). Pronotal disc flat, coarsely granulorugose (Figs 22–23, 51). Anteromedial portion of pronotum with two strongly developed, conical denticles (Figs 51). Posteromedial process of pronotum narrowed basally, distinctly emarginate apically (Figs 39, 51). Colima, Pacific slope of Jalisco and Michoacán (Fig. 66). ..... P. pseudofurcosus Balthasar, 1939

9 Posterolateral portions of pronotum produced into elongate, slender, conical denticles (Figs 18, 37, 49). Anterolateral margins of pronotum without ridge of tubercles (Figs 18, 49). Southern-central slope of the Trans-Mexican Volcanic Belt (Fig. 65). ..................... ............................................... P. herbeus Bates, 1887

– Posterolateral portions of pronotum sharply upturned posteriorly (Figs 32–34, 43–45). Anterolateral margins of pronotum with strongly developed ridge of tubercles (Figs 43–45). Distribution variable (Fig. 64).................................................................................10

10 Multi-coloured pronotum, with sides bright metallic green-yellow, becoming bright red to wine garnet red medially (Figs 6–7, 44). Posteromedial process of pronotum produced into triangular denticle, strongly widened (reaching the anteromedial carina; Figs 33, 44). Los Tuxtlas region, Veracruz (Fig. 64). .............. ............................................. P. moroni Arnaud, 2001

– Green (Figs 1, 3–4, 8–9, 43, 55), occasionally with bright red (Fig. 2) or yellow sheen (Figs 45, 56). Posteromedial process of pronotum produced into triangular denticle, lightly widened (not reaching anteromedial carina; Figs 32, 34, 43, 45). ....................... 11

11 Metallic green with blue (Figs 1, 3–4) or red sheen (Fig. 2). Anteromedial portion of pronotal disc with two flat, sharply upturned triangular tubercles, these tubercles occasionally joined by medial carina (Fig. 43). Posteromedial process of pronotum uniform (Figs 32). Northern to central Veracruz (Fig. 64). ...... .......................................... P. tridens Castelnau, 1840

– Metallic green (Figs 8–9). Anteromedial portion of pronotal disc with two inconspicuous, rounded tubercles or two triangular tubercles never joined by medial carina (Fig. 45). Posteromedial process of pronotum distinctly narrowed medially (Figs 34). Mexico (Chiapas) and Guatemala (Huehuetenango) (Fig. 64). ................................. P. balthasari Arnaud, 2001