Phanaeus (Phanaeus) zapotecus Edmonds, 2006

Edmonds, W. D., 2006, A new species of Phanaeus Macleay (Coleoptera: Scarabaeidae: Scarabaeinae: Phanaeini) from Oaxaca, Mexico, Zootaxa 1171 (1), pp. 31-37 : 32-36

Phanaeus (Phanaeus) zapotecus Edmonds , new species

Figs. 1, 3 , and 5

Type Specimens. Holotype male— MEXICO: Oaxaca, 8 km S Sola de Vega , 1850 m, 4­9 vii 05, D. Curoe col./ mushroom baited trap (approximate coordinates: 16 28’ 50” N; 96 59’ 40” W) . Paratypes (32 males, 48 females)— two males, eight females same data as holotype ; one male 6 mi [~ 10 km] S San Miguel Sola de Vega , 8 vii 94, pino­encino­junipero, Curoe col. ; 20 males, 29 females same data as holotype except 7­17 ix 05, pine oak forest ; three males, two females same data as holotype except 7­17 ix 05, pine oak forest/ f.i.t. [= flight intercept trap] ; four males, eight females same data as holotype except 5­9 x 05, pine oak forest ; one male, one female same data as holotype except 5­9 x 05, pine oak forest/f.i.t .; one male, one female MEX [ICO]: Hwy 131, 70 km S Oaxaca, Río de la Y, Km 20 W of jct., 2150 m, 17 vii 79, H & A Howden (approximate coordinates: 16 40’; 97 01’ W). (The Howden specimens also bear the blue identification label, “ Phanaeus endymion Harold, 1863 n. sp.? W. D. Edmonds 1983.”) All type specimens bear my determination/designation labels, printed in black ink on white paper with blue (holotype) or red (paratypes) lateral margins; they are distributed as follows : Holotype male and three paratypes (one male, two females) deposited in collection of the Instituto de Ecología , Xalapa , Veracruz ( Mexico). Remaining paratypes distributed as follows: Canadian Museum of Nature , Ottawa (two pairs, including the Howden specimens cited above); National Museum of Natural History , Washington, D. C. (two pairs); The Natural History Museum , London (one pair); Universidad Nacional Autónoma de México ( UNAM), México, D.F. (one pair); Muséum National d’Histoire Naturelle, Paris (one pair); and at least one pair of paratypes in each of the following private collections: Richard Cunningham, LaVerne, California; Daniel Curoe, Palo Alto, California; W. D. Edmonds, Marfa, Texas; Miguel Angel Morón, Coatepec, Veracruz; Guillermo Nogueira, Guadalajara, Jalisco; and Fernando Vaz­de­Mello, Lavras, Minas Gerais .

Diagnosis: Phanaeus zapotecus can be separated from the related Mexican species P. endymion by its distinctly granulate (X10) male pronotal disk, sagittal furrow present on the female pronotum, and usually all­black color; and P. halffterorum by its unmodified sutural margin of the elytra, usually all­black color, and Oaxacan distribution ( Fig. 7 ).

Holotype ( Fig. 1 ): Large (major) male, length 17 mm, width 10 mm. Appearing completely weakly shiny black to unaided eye; magnification reveals slight green cast on elytra and femora and brighter green reflections on the undersides of the posterior pronotal angles, femora, and on sides of head horn. Clypeus with two conspicuous median teeth; frons bearing long, slender horn strongly curved over pronotum. Pronotum with expansive, flat triangular disk, with small callosity on each side near anterior margin and with posterolateral angles projecting caudally; sides weakly and sparsely asperate (sharply roughened) with distinct punctures present only behind lateral fossae (X25); triangular disk densely, evenly, and finely granulate; granules extending onto posterolateral angles and becoming effaced along posterior margin where surface appears faintly punctate, slightly swollen, and weakly impressed midlongitudinally. Pronotum with obsolete basal fossae; anterolateral angles subquadrate, distinctly upturned and concave. Elytral striae fine; interstriae convex, evenly but weakly shiny and minutely punctate (X25). Pygidium with obsolete punctures.

The holotype is not the largest male in the type series; it was selected because it shows the least wear of the large males available. This specimen bears glue residue on the right hind coxa and adjacent metasternum used to secure the stainless steel pin. The aedeagus is extracted and mounted on a paper point with a blue tip.

Variation: Dorsum dark, slightly shiny, appearing black to unaided eye except in occasional specimens with conspicuous metallic green on posterior portion of head, pronotum, and/or elytra; metallic coloration most common on male pronotum and elytra, usually confined in female to margin and midlongitudinal impression of pronotal disk. Low (X5) magnification and bright light often reveal, especially in males, weak bluish­green or green luster on areas otherwise appearing black. In smallest individuals, horn reduced to conical tubercle or rounded cusp. Female ( Figs. 3 , 5 ) with low, narrow trituberculate, cephalic carina. In small males, granulate triangular disk progressively smaller, granules becoming squamate behind remnant of disk with asperate sculpturing on sides stronger. Pronotum of female ( Figs. 3 , 5 ) fairly evenly and densely covered with small punctures (X10) on finely roughened surface; punctures becoming smaller on middle of disk, bearing raised anteromedian trituberculate tumosity near anterior margin; tubercles equal­sized and set in more­or­less straight, transverse line; disk with distinct midlongitudinal furrow ( Fig. 3 ) extending forward from posterior margin to about middle of disk, furrow more strongly sculptured than adjacent surface of disk and often with hint of metallic green color. Pygidium with faint to distinct but fine, sparse punctures. Length (including head): 13–20 mm; width at bases of elytra: 7.5–11.5 mm.

Etymology of Species Name. Latinization of zapoteco, Spanish adjective meaning “zapotec” or “zapotecan,” in reference to the indigenous people and places of much of central Oaxaca.

Discussion. Henry and Anne Howden discovered Phanaeus zapotecus in 1979. They collected a pair of individuals in wild toadstools in the Sierra Madre del Sur, south of the city of Oaxaca. The Howden specimens were referred to by me ( Edmonds 1994) as Phanaeus endymion (“ Oaxaca endymion”) with the qualifier: “My guess is that more specimens will support recognizing this Oaxaca population as a distinct species …” Attempts by me and others in the intervening years to collect more individuals were unsuccessful until recently, when Daniel Curoe collected P. zapotecus on three occasions from the same general area. Curoe’s careful field work resulted in 79 additional specimens, which were collected in July, September, and October south of the town of San Miguel Sola de Vega (often cited only as Sola de Vega), Oaxaca. The collection site consists of seasonally dry pine­oak forest with occasional juniper and lies at an elevation of approximately 1850 meters on the leeward (inland valley) slopes of the Sierra Madre del Sur. Most specimens were collected from pitfall traps baited with local mushrooms (one male was collected directly from a mushroom), and there seemed to be a preference for fresh and somewhat aged mushrooms over badly decomposed ones. A few specimens were collected from flight intercept traps while traps baited with human feces and carrion (decomposing squid) yielded no specimens. This species, unlike most of its congeners, is crepuscular. The only other mycetophagous species collected there, Liatongus rhinocoerulus Bates , is active during the day. The only other member of the P. endymion group occurring in the same region is Phanaeus endymion . Barney Streit (pers. comm.) has recently collected this species from pitfall traps baited with decomposing mushrooms on the Pacific side of the Sierra Madre del Sur fairly near Sola de Vega (Hwy. 175, Km. 202­3; 314 m, July, 2005; this site is about 30 air km north of Puerto Angel and 85 air km southeast of Sola de Vega). P. endy­ mion is widely distributed in southern Mexico ( Fig. 7 ) and is commonly found also utilizing human feces.

Phanaeus zapotecus conforms well with the characteristics of the P. endymion species group as defined by Edmonds (1994); the only observed exceptions are in the cephalic tubercle of very small males (which is not perceptibly bidentate in any of the specimens in the type series) and in the front tibiae (which lack a clear, slit­like notch between the third and fourth lateral teeth). The aedeagus is virtually identical to those of P. endymion and P. halffterorum . Besides the characters presented in the key below, P. zapotecus differs from P. endymion by the fact that the male pronotal disk never has distinct, shiny micropuntures (X25) as does that of P.endymion . This new species shares several characteristics with P. halffterorum , another similar species to P. endymion . The shape and sculpturing of the male pronotum are quite similar in P. halffterorum and P. zapotecus ; the female pronotum of both bears a distinct sagittal furrow; and the elytral interstriae are evenly textured (i.e., not distinctly shinier medially). Moreover, the two species are similar ecologically, both being mycetophagous species inhabiting pine­oak montane habitats ( Edmonds 1994).

Edmonds’ (1994) key to members of the P. endymion group included Phanaeus zapotecus (as “ Oaxaca ” specimens) in P. endymion . The following modification of that key will separate it as a distinct species.

1a Sutural margin of each elytron upturned to form a sharp ridge, which is progressively more elevated posteriorly and prolonged into a small, sharp tooth at apical angle; elytral margin slightly excised adjacent to this tooth. Color bright green or dark blue. South­central Mexico (states of Mexico and Guerrero; Fig. 7 ) ..................................... ................................................................................ Phanaeus halffterorum Edmonds

1b Sutural margin of elytra simple. Color and distribution variable.................................. 2

2a Triangular pronotal disk of male ( Fig. 1 ) evenly and densely, but finely granulate (X10), granules usually larger and becoming squamose along lateral margins of disk and extending onto posterolateral angles (when distinctly developed); sides of pronotum roughened (X10), lacking distinct punctures except behind lateral fossae. Female pronotum ( Figs. 3 , 5 ) minutely roughened, evenly, distinctly punctured (X10), punctures becoming smaller dorsally but never disappearing altogether; disk impressed medially as distinct furrow visible to unaided eye, extending forward from posterior margin to near middle of disk. Sierra Madre del Sur, south­central Oaxaca ( Fig. 7 ) .... ................................................................................. Phanaeus zapotecus , new species

2b Pronotal disk of male either lacking distinct granulation, or, if granules present, these are minute and restricted along lateral margins of disk ( Fig. 2 ); sides of pronotum smooth, minutely punctured. Female pronotum ( Figs. 4 , 6 ) smooth, puncturing (X50) fine and usually restricted to sides; median furrow lacking, or at most indicated by fine, scarcely visible line ...........................................(to couplet 2a in Edmonds, 1994)

Figures

FIGURES 1–4. Fig. 1. Phanaeus zapotecus Edmonds, dorsal view male holotype. Fig. 2. Phanaeus endymion Harold, dorsal view male. Fig. 3. Phanaeus zapotecus Edmonds, dorsal view forebody female paratype. Fig. 4. Phanaeus endymion Harold, dorsal view forebody female.

FIGURES 5–7. Fig. 5. Phanaeus zapotecus Edmonds, oblique view female paratype. Fig. 6. Phanaeus endymion Harold, oblique view female. Fig. 7. Known distributions of the Mexican species of the Phanaeus endymion group (sensu Edmonds 1994). Solid circles: collecting sites for P.endymion; stars: P. halffterorum; triangle: P. zapotecus.