Apterodorcus bacchus

E, José Mondaca, 2008, Revision of the genus Apterodorcus Arrow (Coleoptera: Lucanidae: Lucaninae) of southern South America, Zootaxa 1922, pp. 21-32 : 24-29

Apterodorcus bacchus (Hope in Westwood, 1845)

( Figs. 1–2, 4 , 6 , 8 , 10, 12 )

Apterodorcus bacchus (Hope in Westwood, 1845). Holotype (OXUM) examined (Col: 302) labeled: a) “ Chile ”; b) “ Bacchus / Hope”; c) red bordered “ TYPE / HOPE / … / Coll. Hope Oxon.” label with handwritten “Col: Lucan.” / “1845, P. 26”; d) black bordered “ TYPE / … / HOPE DEPT. OXFORD” label with handwritten “Col: 302 / Lucanus / bacchus Hope / (Westw.)”; e) “ Apterodorcus bacchus / (Hope, in Westwood 1845) / det. M.J. Paulsen 2007 / Scarabs S.S.Am. Project DB”.

Lucanus bacchus Hope in Westwood, 1845: 26. (original combination).

Dorcus chilensis Dejean, 1833: 174 . (nomen nudum).

Dorcus bipunctatus F. Philippi, 1859: 656 . (synonym). No type material is present in the MNNC or the National Museum in Prague, where some Philippi types are located. The type series is presumably lost. The synonymy of the taxon is clear from the original description and the designation of a neotype is not warranted.

Description. Males ( Fig. 2 ) n= 339. Females ( Fig. 4 ) n= 302. Length: 20.9 – 35.4 mm. Width: 9.1 – 14.5 mm. Color: Black, surface alutaceous, weakly shiny. Vestiture: Apparently glabrous dorsally. Head: Frons more or less flat, weakly excavated anteromedially, excavation parabolic; sparsely to moderately punctate; punctures fine to moderate, becoming larger and more dense anteriorly and laterally, punctation markedly stronger and denser in female. Temporal process strongly developed laterally; process straight anteriorly and subtriangular in major males ( Fig. 2 ). Male majors with mandibles ( Fig. 6 a) usually as long as head, curved abruptly before apex, apices bifurcate with teeth acute; internally near middle with two obtuse teeth; dorsally with large basal tooth coplanar with dorsal surface (tooth directed posteriorly in male majors). Moderately developed males and male minors with mandibles ( Figs. 6 b, 6c) similar to male major but overall smaller, dorsal tooth directed internally or reduced to gibbosity. Female with mandibles ( Fig. 6 d) flat dorsally, not expanded laterally at base. Pronotum: Anterior angle obtuse, sides widest in anterior third (major males), parallel (minor males, some females) to rounded (most females) to weak angulation in basal third, straight from angulation to posterior angle. Surface punctate; punctures moderate on disc, becoming finer near midline, becoming larger and coalescing near margins. Margins beaded (bead obsolete anteromedially), weakly shiny; anterior margin of female with two shining tubercles; tubercles may be weakly indicated in major males; pubescence along anterior margin usually indistinct (more prominent in females), testaceous. Scutellum: Form parabolic. Size not reduced, rarely depressed below level of elytra. Elytra: Surface somewhat shiny, lacking obvious scales, weakly striate, punctate; punctures fine on disc, becoming larger and coalescing laterally and basally. Wings: Brachypterous in both sexes ( Fig. 8 ). Legs: Mesotibiae and metatibiae with large external tooth, 1–2 smaller teeth proximally. Male Genitalia: Form simple ( Fig. 10 ). Female Genitalia: Similar to other sclerostomines. Illustrated by Weinreich (1960: Fig. 68).

Diagnosis. This species is distinguished from A. tristis by the following combination of characters: Surface generally shinier; lacking distinct band of orange setae along anterior pronotal margin; male mandibles with basal tooth large, coplanar with dorsal surface, and usually directed posteriorly; mesotibiae and metatibiae with 1–2 smaller teeth proximal to large external tooth; females with anterior pronotal margin bituberculate.

Distribution ( Fig. 1 ). Argentina and Chile.

Locality data. 641 specimens examined from CASC, CMNC, CNCI, CSCA, EMEC, FMNH, FSCA, JMEC, MJPC, MNNC, PVGH, UNSM, USNM.

ARGENTINA (29): Neuquén (21): Lago Lolog (6); Pucará (3); San Martín de los Andes (3); No data (9). Río Negro (4): Bariloche (1); El Bolsón (2); El Manso (1). Chubut (4): El Turbio (1); Epuyén (2); Lago Puelo (1).

CHILE (612). VII Región del Maule (51): Reserva Nacional Altos del Lircay (1); Altos de Vilches (13); Estero de Leiva (6); Fundo Malcho (5); Reserva Nacional Los Queules (21); Río Teno, Curicó (3); Tregualemu (5). VIII Región del Biobío (54): Alto Caicupil (1); Atacalco (1); Caramavida (1); Cerro Caracol, Concepción (2); Cordillera Chillán (1); Cordillera Nahuelbuta (2); Chacay, Cerro Nahuelbuta (1); Concepción (4); Contulmo (1); Fundo Caledonia (3); Fundo Los Cipreses (1); La Invernada (2); Las Comadres (6); Las Trancas (2); Mulchen (2); Parque Nacional Nahuelbuta (7); Puente Marchant (9); Quillón, Cerro Cayumanqui (2); Recinto, E of Chillán (4); San Pedro de la Periquita, Concepción (1); Termas de Chillán (3).

IX Región de La Araucanía (211): Angól (2); Bellavista, Lago Villarrica (1); “Cautín” (1); Cherquenco (12); Cunco (73); Curacautín (6); El Cañi Reserve (2); Flor del Lago Ranch (-39º 12.278’, -72º 8.3’) (10); Huichahue (15); Laguna Malleco (20); Manzanares (2); Monumento Natural Contulmo (3); Parque Nacional Huerquehue (4); Parque Nacional Nahuelbuta (5); Pucón, 10 mi NE (8); Puesco, Parque Nacional Villarrica (2); Rari-Ruca (1); Río Trancura (2); Selva Oscura, Curacautín (1); Temuco (3); Temuco, 20–22 km E (19); Victoria (1); Victoria, 4 km W (4); Victoria, Inspector Fernández (3); Villarrica (8); Villarrica, 30 km NE (15); No data (3). X Región de Los Lagos (109): Ahoni Alto, Chiloé (1); Anticura, Parque Nacional Puyehue (37); Chanquin, Parque Nacional Chiloé (1); Chepu, Chiloé (2); Chiloé (2); Cochamo, 5 km E (2); Colonia Yungay, Chiloé (1); Dalcahue, Chiloé (2); Ensenada (1); Lago Chapo (6); Lago Llanquihue (1); Lago Yelcho (1); Las Lomas, Llanquihue (1); Maullín (2); Palena (2); Parque Nacional Vicente Pérez Rosales (La Picada, Refugio, Volcán Osorno) (9); Peulla (1); Piruquina, Chiloé (1); Puerto Varas (2); Pucatrihue (10); Purranque, 30 km W (8); Puyehue, 10–20 km E (6); Río Bueno, Osorno (4); Quellón, Chiloé (3); Ralún, Río Cuarteles (1); Terao, Chiloé (1); No data (1). XIV Región de Los Ríos (47): Chihuio (1); Corral (9); Bosque Santa Rosa, Valdivia (1); Fundo Caupolican, Valdivia (2); Huellelhue (2); Lago Pellaifa (1); Las Trancas, La Unión (1); Liquiñe (1); Los Lagos (1); Neltume (1); Niebla (2); Llancahue (5); Panguipulli (3); Pirihueico (8); Riñihue (2); Santo Domingo de Valdivia (8); Valdivia (4). No data (114).

Temporal data. January (177), February (130), March (8), April (14), May (1), June (2), October (21), November (39), December (117). No data (131).

Remarks. This flightless species has a broad distribution from northern Maule to Los Lagos region, a distance of almost 1,000 kilometers. It has been found from elevations near sea level to 1200 m. We believe the northernmost populations of A. bacchus are represented by a single specimen from “Río Teno, Curicó” in the northern part of VII Region. Our previous collecting has indicated that A. bacchus is not present in the vicinity of Reserva Privada Alto Huemul, in southern VI Region. A few specimens of A. bacchus were examined that were labeled from localities near Santiago, but we have not collected A. bacchus north of central Maule and believe the labels were in error.

We have observed adults in the earth under logs in Nahuelbuta, and feeding on sap from Nothofagus trees in several localities ( Fig. 12 ), both during the day and at night. In some areas, such as the Maulino forest of Reserva Nacional Los Queules, adults are commonly encountered walking during the day. Ruiz (1924) discussed the collection of a few hundred specimens from several wounded Nothofagus trees, but his observations lack credibility inasmuch as his larval observations appear to refer to a species of moth, Chilecomadia valdiviana ( Lepidoptera : Cossidae ). Furthermore, the female illustrated by Ruiz (1924) is in fact a major male. Nevertheless, he indicated that no male fighting was observed despite the large number of beetles, and that mating was occurring at the sap flows. Interestingly, Ruiz indicated that man-made tree wounds did not attract beetles.

Figures

FIGURE 1. Distribution of Apterodorcus species: A. bacchus (circles), and A. tristis (triangles). Regions of Chile indicated by Roman numeral, provinces of Argentina by postal code (Q = Neuquén, U = Chubut, R = Río Negro).

FIGURES 2 – 5. Dorsal habitus of Apterodorcus species: 2) A. bacchus, major male; 3) A. tristis, major male; 4) A. bacchus, female; 5) A. tristis, female.

FIGURE 12. Female A. bacchus feeding at sap flow on Nothofagus near Chillán, VIII Region.

FIGURES 6 – 7. Mandibular development in 6) Apterodorcus bacchus and 7) A. tristis, shown for each species: a) major male, b) moderately developed male, c) minor male, d) female.

FIGURES 8 – 11. Wings and male genitalia of Apterodorcus species: 8) Brachypterous right wing of A. bacchus male; 9) Brachypterous right wing of A. tristis male, with right elytron for scale. 10) Male genitalia of A. bacchus; 11) Male genitalia of A. tristis. Scale bars indicate 1 mm.