Onthophagus etlaensis Kohlmann, Escobar-Hernández, and Arriaga-Jiménez, 2020

Arriaga-Jiménez, Alfonsina, Escobar-Hernández, Fernando, Rös, Matthias & Kohlmann, Bert, 2020, The establishment of the Onthophagus anthracinus (Coleoptera: Scarabaeidae) species complex and the description of a new species, The Canadian Entomologist 152 (1), pp. 1-17 : 2-11

Onthophagus etlaensis Kohlmann, Escobar-Hernández, and Arriaga-Jiménez , new species

http://zoobank.org/ urn:lsid:zoobank.org:act:83069DD6-F365-4A47-B964-52DA349CE5B8 .

Figures 1, 2 , 5–6 , 13 , 19 , 22 . Type material. Holotype male pinned. Original label: “Reserva Comunitaria San Pablo, Etla,

Oaxaca. 27-IX-16, coprotrampa, x- 96.718644° O, y- 17.17699° N, bosque de encino, 2443 m ,

Arriaga A. & Arenas A. Col. ” and “ HOLOTYPE / Onthophagus etlaensis Kohlmann, Escobar-Hernández, Arriaga-Jiménez ” (red printed label) deposited in the Colección Entomológica (Entomology Collection), Instituto de Ecología , Xalapa , Mexico. Allotype female: “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-VI-17, coprotrampa, x- 96° 43’ 50.34” W, y- 17° 10’ 15.64” N, bosque de encino, 2219 m, Arriaga J.A. Col. ” and “ ALLOTYPE / Onthophagus etlaensis Kohlmann, Escobar-Hernández, Arriaga-Jiménez ” (light blue printed label).

Paratypes (76 males, 130 females): “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 12-VII-17, coprotrampa, x- 96° 43’ 47.02” W, y- 17° 10’ 16.19” N, bosque de encino, 2193 m, Arriaga A. y Arenas A. Col. ” (one male, three females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 14-VII-17, coprotrampa, bosque de encino, 2193 m, Arriaga A. y Arenas A. Col. ” (two females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.685011°, y- 17.167224°, bosque de pino, 2983 m, Arriaga A. y Arenas A. Col. ” (two males, 11 females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.733014°, y- 17.170797°, bosque de encino, 2133 m, Arriaga A. y Arenas A. Col. ” (nine males, 12 females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-VI-17, coprotrampa, x- 96° 43’ 51” W, y- 17° 10’ 14” N, bosque de encino, 2205 m, Arriaga J.A. Col. ” (three females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 14-VII-17, coprotrampa, x- 96° 43’ 47.02” W, y- 17° 10’ 16.19” N, bosque de encino, 2193 m, Arriaga A. y Arenas A. Col. ” (two females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.685011°, y- 17.167224°, bosque de pino, 2983 m, Arriaga A. y Arenas A. Col. ” (five females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla, Oaxaca. 10-VII-17, coprotrampa, x- 96° 43’ 21” W, y- 17° 10’ 29” N, bosque de encino, 2343 m Arriaga A. y Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla, Oaxaca. 12-VII-17, coprotrampa, x- 96° 43’ 21” W, y- 17° 10’ 29” N, bosque de encino, 2343 m Arriaga A. y Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa, x- -96.723379°, y- 17.176195°, bosque de encino, 2302 m, Arriaga A. y Arenas A. Col. ” (two females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- -96.723379°, y- 17.174158°, bosque de encino, 2271 m, Arriaga A. y Arenas A. Col. ” (four males, two females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- -96.725892°, y- 17.173568°, bosque de encino, 2256 m, Arriaga A. y Arenas A. Col. ” (three males, five females) ( IEXA); “ México. San José del Pacífico, Miahuatlán, Oaxaca. 31-VIII-17, coprotrampa, x- -96.50903°, y- 16.16460°, bosque pino/encino, 2325 m, Arriaga J.A. Col. ” (one male, two females) ( IEXA) ; “ México. San José del Pacífico, Miahuatlán , Oaxaca. x- -96.51173°, y- 16.16972°, bosque mesófilo, 2316 m, Arriaga J.A. Col. ” (four males, nine females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.732843°, y- 17.17034°, bosque de encino, 2138 m, Arriaga A. y Arenas A. Col. ” (two males, six females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 12-VII-17, coprotrampa, x- 96° 43’ 51.37” W, y- 17° 10’ 12.32” N, bosque de encino, 2186 m, Arriaga A. y Arenas A. Col. ” (two males, two females) ( IEXA). “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 29-V-17, C.D. exc. vaca, x- 96° 0’ 43.28” W, y- 17° 6’5.5” N, pastizal, 2411 m, Arriaga J. A. Col. ” (one male, three females); ( IEXA) “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 28-V-17, coprotrampa, x- 96° 1’ 57.20” W, y- 17° 8’59.41” N, acahual, 2623 m, Arriaga J. A. Col. ” (one male) ( IEXA); “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 30-V-17, coprotrampa x- 96° 1'55.23"W, y- 17° 8'59.28"N acahual / maíz, 2626 m. Arriaga- Jiménez, A. Col. ” (one male) ( IEXA); “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 29-V-17, coprotrampa x- 96°0'43.28'' W, y- 17°6'5.5'' N, pastizal, 2411 m, Arriaga- Jiménez, A. Col. ” (three males, two females) ( IEXA); “ México. Zempoaltépetl, Santa María Yacochi , Oaxaca. 30-VII-17, coprotrampa x- 96° 2’ 52.27” W, y- 17° 9’52.46” N, acahual, 2406 m, Arriaga J. A. Col. ” (one male, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa, x- -96.736763°, y- 17.16688°, bosque de encino, 1995 m, Arriaga A. y Arenas A. Col. ” (two males, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. x- -96.72376°, y- 17.17591°, bosque de encino, 2309 m, Arriaga A. y Arenas A. Col. ” (one male, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. x- -96.725454°, y- 17.17433°, bosque de encino, 2276 m, Arriaga A. y Arenas A. Col. ” (three males, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.732348°, y- 17.170968°, bosque de encino, 2155 m, Arriaga J. A. Col. ” (two males, three females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 27-IX-16, coprotrampa, x- -96.718872°, y- 17.177351°, bosque de encino, 2410 m, Arriaga J. A. Col. ” (one male, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.732386°, y- 17.170454°, bosque de encino, 2151 m, Arriaga J. A. Col. ” (five males, four females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 17-VI-17, coprotrampa, x- 96°43’19’’ W, y- 17° 10’ 31.31’’ N, bosque de encino, 2366 m, Arriaga J. A. Col. ” (one male, one female) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 12-VII-17, coprotrampa, x- 96°43’52.5’’ O, y- 17° 10’ 13.’’ N, bosque de encino, 2195 m, Arriaga A. & Arenas A. Col. ” (one male, two females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa, x- -96.72534°, y- 17.173835° N, bosque de encino, 2256 m, Arriaga A. & Arenas A. Col. ” (two females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. x- -96.723151°, y- 17.175643°, bosque de encino, 2323 m, Arriaga A. & Arenas A. Col. ” (three females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 10-VII-17, coprotrampa, x- 96°43’23.31’’ W, y- 17° 10’ 30.07’’ N, bosque de encino, 2349 m, Arriaga J. A. Col. ” (five males) ( IEXA); 20-VIII-17, coprotrampa, “ México. La Mesita, San Pablo Etla , Oaxaca. x- 96°44’25’’ W, y- 17° 09’ 50’’ N, bosque de encino, 1935 m, Arriaga J. A. Col. ” (five males, 16 females) ( IEXA); “ México. La Mesita, San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa, x- -96.723551°, y- 17.175472°, bosque de encino, 2325 m, Arriaga A. & Arenas A. Col. ” (one male, four females) ( IEXA); “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 30-V-17, coprotrampa x- 96° 1’ 55.23” W, y- 17° 8’ 59.28” N, acahual, 2626 m, Arriaga J. A. Col. ” (one male) ( IEXA); “ México. Zempoaltépetl, Santa María Tlahuitoltepec , Oaxaca. 27-VII-17, coprotrampa x- 96° 4’ 31” W, y- 17°6’ 20.40” N, bosque de galería, 2583 m, Arriaga J. A. Col. ” (one female) ( IEXA). “ México. Zempoaltépetl, Santa María Yacochi , Oaxaca. 29-VII-17, coprotrampa x- 96° 0’ 35.36” W, y- 17° 06’ 5.43” N, acahual, 2471 m, Arriaga J. A. Col. ” (one female) ( IEXA); “ México. Zempoaltépetl, Santa Maróa Tlahuitoltepec , Oaxaca. 27-V-17, coprotrampa x- 96° 0’ 33” W, y- 17° 06’ 08” N, lindero ilites, 2445 m, Arriaga J. A. Col. ” (one male) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 27-IX-16, coprotrampa, x- -96.718644°, y- 17.17699°, bosque de encino, 2443 m, Arriaga A. & Arenas A. Col. ” (two females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa, x- -96.72534°, y- 17.17699°, bosque de encino, 2443 m, Arriaga A. & Arenas A. Col. ” (one male) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- -96.723551°, y- 17.175472°, bosque de encino, 2326 m, Arriaga J. A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- -96.725987°, y- 17.174158°, bosque de encino, 2271 m, Arriaga A. & Arenas A. Col. ” (two males) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa, x- -96.732843°, y- 17.17034°, bosque de encino, 2138 m, Arriaga A. & Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- - 96.733014° O, y- 17.170797°, bosque de encino, 2133 m (one male) ( IEXA); 14-VII-17, coprotrampa, x- 96° 44’ 53.55’’ O, y- 17° 9’ 53.55’’ N, bosque de encino, 1954 m, Arriaga A. & Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- 96°44’20’’ O, y- 17° 9’ 54’’ N, bosque de encino, 1974 m, Arriaga A. & Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-VI-17, coprotrampa, x- 96° 43’ 50’’ W, y- 17° 10’ 15’’ N, bosque de encino, 2219 m, Arriaga A. & Arenas A. Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 20-VIII-17, coprotrampa, x- 96° 44’ 25” W, y- 17° 09’ 50” N, bosque de encino, 1935 m, Arriaga J.A. Col. ” (four males, six females) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 27-IX-16, coprotrampa, x- 96° 71’ 86.44” W, y- 17° 17’ 07” N, bosque de encino, 2443 m, Arriaga, A. & Arenas, A., Col. ” (two males) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- 96° 72’ 03” W, y- 17° 17’ 05” N, 2309 m, Arriaga, A. & Arenas, A., Col. ” (one male) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- 96° 71’ 86.14” W, y- 17° 17’ 07” N, 2443 m, Arriaga, A. & Arenas, A., Col. ” (one male) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 23-VI-17, x- 96° 43’ 50.34” W, y- 17° 10’ 06.36” N, 2435 m, Arriaga, J.A., Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- 96° 43’ 07” W, y- 17° 10’ 06.36” N, Arriaga, J.A., Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. x- 96° 43’ 50.34” W, y- 17° 10’ 15” N, Arriaga, J.A., Col. ” (one female) ( IEXA); “ México. Reserva Comunitaria San Pablo Etla , Oaxaca. 10-VII-17, x- 96° 43’ 22” W, y- 17° 10’ 29” N, 2343 m, Arriaga, J.A., Col. ” (one female) ( IEXA); “ México. San José del Pacífico, Miahuatlán , Oaxaca, 31-VIII-17, coprotrampa, x- -96.51173°, y- 16.16972°, bosque mesófilo, 2316 m, Arriaga, J.A., col.” (two males, one female) ( IEXA); “ México, San José del Pacífico, Miahuatlán , Oaxaca. 31-VIII-17, coprotrampa. x- -96.51173, y- 16.16972°, bosque mesófilo, 2316 m. Arriaga J.A. Col. ” (two females) ( JB); “ México. Santa María Tlahuitoltepec , Oaxaca, 29-V-17, C.D. exc. vaca. x- 96°0’43.28’’W, y- 17’6’5.55’’N, pastizal, 2411 m. Arriaga J.A. col.” (two males) ( JB); “ México, Reserva Comunitaria San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa x- -96.725987°, y- 17.174158°, bosque de encino, 2271 m. Arriaga A. & Arenas A. col.” (two males) ( JB); “ México, San José del Pacífico, Miahuatlán , Oaxaca. 31-VIII-17, coprotrampa. x- -96.51173°, y- 16.16972°, bosque mesófilo, 2316 m. Arriaga J.A. Col. ” (two females) ( CEMT); “ México, Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa. x- -96.723551°, y- 17.175472°, bosque de encino, 2325 m. Arriaga A. y Arenas A. Col. ” (two females) ( CEMT); “ México, Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa. x- -96.732386°, y- 17.170454°, bosque de encino, 2151 m. Arriaga A. y Arenas A. Col. ” (two males) ( CEMT); “ México. Oaxaca. 20 miles South Juchatengo , 6000 27-30.v.71 S. Peck ” (one male, two females) ( CMNC); “ México. Oaxaca. 20 miles South Juchatengo , 6000’, 28-30.v.71 S. Peck ” (two males) ( CMNC); “ México. Oaxaca. 20 miles South Juchatengo 6000’, Rt. 131, V.27-30, 1971 H.F. Howden ” (two males, four females) ( CMNC); “ México, San José del Pacífico, Miahuatlán , Oaxaca. 31-VIII-17, coprotrampa. x- - 96.51173 W, y- 16.16972°N, bosque mesófilo, 2316 m. Arriaga J.A. Col. ” (two females) ( CMNC); “ México, Reserva Comunitaria San Pablo Etla , Oaxaca. 23-IX-16, coprotrampa. x- - 96.723551 W, y- 17.175472°N, bosque de encino, 2325 m. Arriaga A. y Arenas A. Col. ” (one male, one female) ( CMNC); “ México, Reserva Comunitaria San Pablo Etla , Oaxaca. 20-IX-16, coprotrampa. x- - 96.732386 W, y- 17.170454°N, bosque de encino, 2151 m. Arriaga A. y Arenas A. Col. ” (one male, one female) ( CMNC) .

Type locality. La Mesita, San Pablo Etla (17°9 0 50.68 00 N, 96°44 0 25.92 00 W, 1935 m), Oaxaca, Mexico .

Diagnosis. Pygidium almost flat; very shallowly, indistinctly punctate; alutaceous basally; apex slightly to moderately shiny. Large pronotal punctures (75 μm) separated about one diameter with distinct margins, not umbilicate, with a shiny ring and small shallow secondary nonsetate punctures sparsely interspersed. Pronotum crossed longitudinally and in the middle by a sulcus in major males, surrounding pronotal area convex.

Description. Holotype. Major male ( Figs. 1–2 ). Length: 6.1 mm. Humeral width: 3.4 mm. Weakly shiny, opaque black. Clypeal margin sharply reflexed anteriorly, feebly so laterally; anterior edge faintly emarginate. Clypeal disc with few coarse punctures distributed across width. Frons with scattered shallow punctures. Clypeal disc and frons almost flat and lacking both clypeal and frontal carinae, the latter being poorly developed behind the eyes; surface between punctures finely alutaceous. Genal margin noticeably arcuate laterally, anteriorly forming a distinct, obtuse indentation with the clypeal margin; gena sharply and obtusely angulate posteriorly opposite the pronotal angles; genal surface slightly concave and with scattered, shallow punctures. Small eyes, five facets wide and emarginate, separated by about 16 eye widths. Occiput with scattered shallow punctures.

Pronotum ( Fig. 13 ) moderately convex and margined anteriorly and laterally, pronotal protuberance conical broad and evenly arched, weakly projecting over the posterior portion of the head. Pronotal surface distinctly alutaceous and with two sizes of punctures: larger punctures annular with margins sharply defined, centrally with an erect reddish-yellow seta, the large punctures usually separated by approximately one diameter; small secondary punctures half the diameter of large punctures and not as numerous, scattered among large punctures, umbilicate in shape and lacking setae. Elytral striae with feebly shiny and vaguely punctate; intervals opaquely alutaceous with irregular double rows of small shiny tubercles; the base of each tubercle with a fine, reddish-yellow seta. Pygidium slightly longer than broad; opaquely alutaceous, slightly to moderately shiny apex, only slightly convex; covered sparsely with pale yellow setae, interspersed with small shiny punctures. Ventral surfaces, including antennae, black to blackish brown. Metaventrite surface coarsely punctate, more so laterally where the surface between punctures is finely alutaceous; base of metaventrite with large, coarse punctures, each bearing pale yellow setae. Ventrites, except for the first, with a row of setigerous punctures across their basal margin; last segment narrowed medially. Aedeagus like in Figure 19 . Lamella copulatrix like in Figure 22 . Prothoracic legs greatly elongate, the apices of the profemora extending slightly beyond the pronotal margin; protibiae long, slender, and recurved, with a pronounced apical conical projection and a long yellow pencil of setae protruding above the apical spine; all femora with scattered, coarse punctures, each puncture bears a pale yellow seta.

Variation. Length: 4.5–6.7 mm. Width: 2.5–3.5 mm. The colour of the lateral side and apical bor- der of the elytra can vary from black to reddish brown.

Male pronotal protuberance can vary from evenly rounded to slightly notched in the middle. Male minors with pronotum less convex, protibiae with apical projection shorter, profemur barely extending to the lateral pronotal margin.

Females differ with clypeus slightly reflexed anteriorly, broadly, somewhat angularly emarginate; clypeal disc coarsely, rugousely punctate, punctures often with brownish-yellow setae; clypeal carina distinct (sometimes absent) but only slightly and rather evenly elevated above clypealfrontal surface. Frons behind carina with a few distinct coarse punctures; frontal carina low but distinct, generally of uniform height; gena scarcely flared, only very obtusely angulate near pronotal angles and with coarse punctures. Area between female clypeal and frontal carina can vary from slightly to heavily and coarsely punctate. Pronotum less convex, pronotal protuberance indicated by a rounded swelling. Pygidium approximately as broad as long. Prothoracic legs stubby and shorter and the apex of the profemur barely reaches the lateral pronotal margin; protibia proportionately shortened; apical projection and pencil of setae lacking; apical spine as long as the three basal tarsomeres. Last ventrite not emarginate, approximately the same width throughout.

Etymology. Etla ensis. Etla being a Nahuatl word, meaning: “Place where beans are abundant”. Also, this is the name of the locality, San Pablo Etla. The order of authorship for this new species reflects the amount of work contributed to the description.

Distribution and ecology. This species occurs in Oaxaca, Mexico ( Fig. 5 ) at Reserva Comunitaria San Pablo Etla (Sierra Norte), 1900–3000 m; San José del Pacífico, San Mateo Río Hondo and south of Juchatengo (Sierra Sur), 1800–2500 m; Sierra Mixe at Zempoaltépetl, Santa María Tlahuitoltepec, and Santa María Yacochi, from 2400–2600 m. It has been collected in acahual (abandoned agricultural fields undergoing regeneration), grassland, cloud forest, Quercus Linnaeus ( Fagaceae ) forests, and Pinus - Quercus forest ( Pinus Linnaeus , Pinaceae ) and seems to be more abundant in Quercus forests. Specimens have been collected using dung-baited and carrion-baited pitfall traps, by hand, and in cattle ( Bos taurus Linnaeus, 1758 ; Artiodactyla : Bovidae ) and horse ( Equus caballus Linnaeus, 1758 ; Perissodactyla : Equidae ) manure.

Taxonomic placement. Onthophagus etlaensis belongs to the O. anthracinus species complex, part of the O. landolti species group. This species has many similarities to O. anthracinus . Onthophagus etlaensis has larger pronotal punctures (75 μm), separated by at least one diameter, pronotum traverse along its middle longitudinally by an evident sulcus in major males and the pronotal area around it convex; whereas, O. anthracinus has smaller pronotal punctures (50 μm) separated by 1–2 diameters, pronotal midline well marked in major males and the pronotal area around it flattened and forming a rhombus. The pygidium of O. etlaensis is opaquely alutaceous and is slightly to moderately shiny, much less so than in O. alluvius or O. durangoensis .

The aedeagus has been studied for this species complex ( Figs. 16–20 ). All species north of the Isthmus of Tehuantepec, including O. etlaensis , have an evident ring near the base of the aedeagus. On the contrary, O. anthracinus has a poorly developed and indistinct ring at the phallobase ( Fig. 17 ). There are also fine differences in the structure of the parameres separating O. etlaensis from O. anthracinus ; the first species has a straight frontal margin of the parameres as seen in lateral view, whereas the second species has a curved margin ( Figs. 17, 19 ); the first species has a slender apex of the parameres as seen in the lateral view, whereas the second species has a much broader apex ( Fig. 1 ). The lamella copulatrix of the internal sac ( Figs. 21–22 ) is very similar in both species. These characteristics hold true for the populations examined from O. anthracinus originating from Chiapas ( Mexico), Guatemala, and Costa Rica. As Howden and Cartwright (1963) observed, the type of punctures is one of the main characters for separating the different species. The Oaxacan specimens are constant in having large punctures (75 μm), whereas the specimens studied from Chiapas to Costa Rica have consistently smaller (50 μm) punctures.

It seems likely that Bates (1887: 77) in his redescription of O. anthracinus included specimens of O. etlaensis , as he indicated Oaxaca and Juquila as distribution localities.

Habitat affinities. Onthophagus etlaensis occupies similar ecological niches to O. anthracinus : Quercus , Pinus - Quercus , and Pinus forests in mountainous regions ( Fig. 6 ).

Figures

Figs. 1–4. Onthophagus etlaensis and O. anthracinus habitus. 1, Onthophagus etlaensis dorsal view; 2, O. etlaensis anterolateral view; 3, O. anthracinus dorsal view; 4, O. anthracinus anterolateral view.

Fig. 5. Map of the known distribution of Onthophagus etlaensis (blue dots). Orography of Oaxaca is shown, based on the digital elevation model downloaded from www.inegi.org.mx. Grey areas show the extent of Mexico, see map in the upper left for the location of the state of Oaxaca within Mexico.

Fig. 6. Typical habitat of Onthophagus etlaensis: San Mateo Río Hondo, Sierra Sur, Pinus-Quercus forest.

Figs 13–15. Species in the Onthophagus anthracinus species complex. 13, Male pronotum of Onthophagus etlaensis; 14, male pronotum of Onthophagus anthracinus; 15, dorsal view of a male Onthophagus durangoensis.

Figs 16–20. Aedeagi of the Onthophagus anthracinus species complex. 16, Onthopagus alluvius; 17, O. anthracinus; 18, O. durangoensis; 19, O. etlaensis; 20, O. mextexus.

Figs 21–22. Lamella copulatrix and accesory lamellae. 21, Onthophagus anthracinus; 22, O. etlaensis.