Orizabus vulcanicus Morón, Tapia and Aragón, 2003

Morón, Miguel Angel, Tapia, Ana María & Aragón, Agustín, 2003, Two new species of the genus Orizabus Fairmaire (Coleoptera: Scarabaeidae: Dynastinae) from southern and central Mexico, Zootaxa 176, pp. 1-8 : 2-4

Orizabus vulcanicus Morón, Tapia and Aragón , sp. nov. ( Figs. 1­9 )

Diagnosis. This species is distinguished from other Orizabus species by the following combination of characters: head with transverse clypeal carina straight, a weak tubercle on fronto­clypeal suture, antennae with 9 segments, pronotum without anterior tubercle and depression, male foretibia lacking teeth; female foretibia tridentate, female pygidium with fine keel along midline.

Description. Holotype. Male: Length 15.8 mm; width across humeri 8.1 mm. Color shiny reddish brown dorsally and ventrally. Head: clypeus with surface finely and transversely rugose; apex broadly rounded; transverse clypeal carina prominent, nearly straight.

Frons moderately convex, with numerous shallow punctures; with short, rounded tubercle on anterior margin at middle of fronto­clypeal suture. Interocular width equals 7.5 transverse eye diameters ( Figs. 1­3 ). Antenna with 9 segments, club 1.2 times longer than stem. Pronotum: surface shiny, disc moderately punctate except along midline; punctures deep and round, with anterior angles rugopunctate. Anterior margin without tubercle and depression. Posterior margin with weak, marginal line, line broadly interrupted at middle. Elytra: surface with 7 impressed rows of small, round punctures between suture and lateral edge of humeral umbone, plus 1 short row at base of second interval, sides with 3 irregular rows. Intervals shiny. Pygidium : surface moderately convex in lateral view, finely rugopunctate at basal angles; disc nearly smooth, with sparse punctures. Ve n te r: prosternal process short, weakly acuminate, densely clothed with long ferruginous setae. Legs: foretibia without teeth, blade­like ( Fig. 4 ). Hindtibia with submedial transverse carina distinct ( Fig. 6 ). Parameres ( Figs. 8­9 ): apical portion of each paramere progressively curved, not expanded, without tooth or membranes.

Allotype. Length 17.2 mm; width across humeri 8.9 mm. As holotype except as follow: Head: tubercle on fronto­clypeal suture broad. Pronotum: posterior margin with middle of marginal line represented by punctures. Pygidium : disc with fine keel along midline and with weak, irregular, longitudinal striae on each side, striae becoming obsolete before apical border. Legs: foretibia nearly tridentate ( Fig. 5 ). Genital plates ( Fig. 7 ): basal plates subquadrate, with some short setae. Distal plates shallowly excavated, with apical border widely rounded, with many setae.

Variation (6 paratypes). Length 15.0­18.0 mm. Humeral width 7.0­9.0 mm. Disc of pygidium in females with midline keel shortened or lacking longitudinal striae on each side of keel.

Material examined (8 specimens). Holotype male: MEXICO. Puebla: Parque Iztaccíhuatl­Popocatépetl, 3600 m, 9 March 2001, Col. A. M. Tapia ( MXAL / IEXA). Allotype female: ibid. ( MXAL / IEXA). Paratypes. Ibid., 3 males, 2 females; ibidem, 3640 m, 15 Aug. 2002, Col. A. Aragón, 1 male ( MXAL / IEXA; MNHN; UNSM).

Habitat. The specimens were collected during the sampling of soil in pine forest at 3600­3640 m elevation. Orizabus vulcanicus apparently is not attracted to lights. In the same locality males and females of Orizabus rubricollis Prell were observed flying in abundance during July, but they also were scarcely attracted to mercury vapor lights.

Geographical distribution ( Fig. 10 ). This species is known only from Parque Iztaccíhuatl­Popocatépetl, Puebla, Mexico.

Taxonomic relationships. Orizabus vulcanicus is in the group of species whose males lack a pronotal tubercle and pronotal depression and have the foretibia without teeth. This group also includes O. rubricollis Prell and O. cuernavacensis Delgado­Castillo and Deloya. The males of O. vulcanicus are easily separated from the other species in this group species by the antenna with 9 segments, small body size, and the apex of parameres without setae.

Etymology. The name refers to the volcanic area where the species was collected, the lower slopes between the volcanoes Iztaccíhuatl and Popocatépetl.

Figures

FIGURE 10. Distribution of Orizabus vulcanicus (q) and Orizabus dechambrei (x).

FIGURES 1 ­ 9. Orizabus vulcanicus Morón, Tapia and Aragón, sp. nov. 1 ­ Male head, dorsal view; 2 ­ Male head and pronotum, lateral view; 3 ­ Male clypeal carina, frontal view; 4 ­ Male foretibia, dorsal view; 5 ­ Female foretibia, dorsal view; 6 ­ Male hindtibia, lateral view; 7 ­ Female genital plates, ventral view; 8 ­ Male genital capsule, lateral view; 9 ­ Parameres, distal view. Scale bar 1 mm.