Strigoderma tenebrosa Delgado & Mora-Aguilar

Delgado, Leonardo & Mora-Aguilar, Eder F., 2012, A new Mexican species and new taxonomic and distributional data of Strigoderma Burmeister (Coleoptera: Scarabaeidae: Rutelinae), Zootaxa 3597, pp. 47-52 : 48

Strigoderma tenebrosa Delgado & Mora-Aguilar , new species

( Figs. 1–3 )

Type material. Holotype male, two males paratypes, and one female paratype labeled: “ MEXICO: Chiapas, Villaflores, Finca Santa Elena, 12-VI-2001, C. J. Morales col.” One male paratype with same data as holotype, except: 22-VI-2001. The holotype and one female paratype are deposited in IEXA. Three male paratypes are deposited in the following collections: CUACH, EMAC, and LLDC.

Description. Holotype male. Length: 7.7 mm, width: 4.1 mm. Form oval-elongate. Color black, with green and purple luster on head, pronotal disc, scutellum, legs, and venter. Head: Clypeus trapezoidal, lateral margins rounded, apex slightly emarginate and moderately reflexed; frons and clypeus with dense, deep and subrugose punctation; interocular distance equals 5.0 transverse eye diameters; antennae with 9 antennomeres, club subequal to funicle. Pronotum: hexagonal, moderately convex, almost as wide as long (1.0:1.2), sides widest at apical third, anterior angles acute, posterior angles obtuse, base sinuate to sides of scutellum; entire surface with punctation fine and confluent. Scutellum: with fine and dense punctures. Elytra: longer than wide (1.9:1.0), narrowed to the apex; surface granular, microreticulate, with some small punctures towards the apex; with four acute elevated ridges with vestigial ridges interspersed between. Abdomen: Apical region of propygidium with scarce, short setae; pygidium convex, wider than long (1.3:1.0), with punctation fine to moderate in size, moderately dense, with sparse, moderately setae; sternites concave, surface microreticulate with irregular punctation and each one with a transverse row of long, pale yellow setae. Venter: Prosternum with white setae in the middle; mestasternum with large, dense, white setae at the sides; disc glabrous; meso-metasternal process rounded, not elevated. Legs: Protibiae bidentate; protarsi and mesotarsi short and thickened, apical protarsomere larger than the rest combined; inner proclaw elongate, as long as the apical protarsomere, cleft, inner ramus equals 0.3 the length of outer ramus ( Fig. 1 ); meso- and metatibia slightly widened at middle and with two diagonal carinae with accompanying spinules. Genitalia ( Figs. 2–3 ): Parameres elongate, convergent to the apex, scarcely bent in lateral view.

Paratypes (3 males, 1 female). Total length: 7.4–8.0 mm; width: 3.8–3.9 mm. Male paratypes differ from the male holotype in the following respects: head and pronotum with shiny reflections, and tarsi black to reddish brown. In the female paratype the elytral color black with irregular maculae dark reddish-brown, pronotal disc dull green and swollen, antennal club shorter than the funicle, elytra with the second broad interval without costae elevated, epipleura slightly wider, abdominal sternites convex in lateral view, teeth of protibia elongate and projected apically, tarsi not thickened and claws not enlarged, rami subequal in length.

Etymology. The specific epithet is derived from the Latin tenebrosus, meaning dark, in reference to the dark color of this species.

Remarks. Strigoderma tenebrosa possesses characters states that place it in the Strigoderma costulipennis species group: surface of elytra granular and with acute or shallow elevated ridges. Strigoderma tenebrosa is distinguished from S. tomentosa by the pronotal punctation fine and dense, and the acute, elevated elytral ridges (pronotum coarsely punctuate with shallow, elytral ridges in S. tomentosa ). Strigoderma tenebrosa is separated from S. costulipennis by the total length greater than 7.4 mm (7.0 mm or less in S. costulipennis ), by the inner proclaw in the male as long as the apical tarsomere with the inner ramus 0.3 the length of the outer ramus ( Fig. 1 ) (male inner proclaw in S. costulipennis shorter than the apical tarsomere with the inner ramus 0.7 the length of the outer ramus as in Fig. 4 ), and by the male genitalia ( Figs. 2–3 versus Figs. 5–6 ).

Distribution. Strigoderma tenebrosa is known only from a locality situated at the Central Depression of Chiapas, Mexico. This species was collected in areas with tropical deciduous forest at 600 m of elevation. By contrast, S. costulipennis is distributed west of the Isthmus of Tehuantepec, in the states of Colima, Guerrero, Jalisco, Michoacán, Morelos, Nayarit, Oaxaca, and Puebla ( Morón 1997), although the distant record of the state of Coahuila mapped by Bader (1992) needs confirmation. Strigoderma tomentosa was described from the state of Oaxaca, Mexico, and after cited by Bader (1992) from Nicaragua ( Fig. 10 ).

Figures

FIGURE 10. Geographical distribution of S. costulipennis (dots), S. tomentosa (square), and S. tenebrosa (triangle).

FIGURES 1 – 9. Diagnostic structures of Strigoderma species. 1 – 3) S. tenebrosa: 1) Protarsal claws; 2) Parameres in frontal view; 3) Parameres in lateral view. 4 – 6) S. costulipennis: 4) Protarsal claws; 5) Parameres in frontal view; 6) Parameres in lateral view. 7 – 9) S. longicollis: 7) Parameres in frontal view; 8) Parameres in lateral view; 9) Tips of parameres in ventral view. Scale lines = 1 mm.