Pachystethus ixtacomitanus Ramírez-Ponce & Morón, 2012

Ramírez-Ponce, Andrés & Morón, Miguel Angel, 2012, Revision of the genus Pachystethus Blanchard with description of three new species from Mexico (Coleoptera: Scarabaeidae: Rutelinae: Anomalini), Zootaxa 3394, pp. 1-24 : 18-21

Pachystethus ixtacomitanus Ramírez-Ponce & Morón , new species

( Figs. 36–41 , 47 a–b, 53)

Type material (12 males, 10 females). Holotype male housed at CNIN with following label data: a) “ México: Chiapas, Ixtacomitán, Río Blanco, 10-XII-85. Col. F. Arias, L. Cervantes y R. Barba” (typeface), b) “Colección del Instituto de Biología, UNAM, México, D. F.” (typeface), c) our holotype red label. Allotype female housed at CNIN with following label data: a) “ México: Chiapas, Ixtacomitán, Río Blanco, 10-XII-1985. Col. F. Arias, L. Cervantes y R. Barba” (typeface), b) Instituto de Biología, UNAM, México, D. F.” (typeface), c) our allotype yellow label. Paratypes (11 males, 9 females) with our paratype yellow labels and following label data: same data as holotype (2 males, 4 females, CNIN; 2 males, 1 female, IEXA; 1 male, MXAL) (typeface); “ México: Chiapas, Soluchistan, 11-XII-85. F. Arias, L. Cervantes” (typeface) (2 males, CNIN); “ México: Chiapas, Ixhuatán, Km 3 carr. Pozo Rosarito, 12-XII-1985, F. Arias. R. Barba, L. Cervantes” (typeface) (1 male, CNIN); “ México: Chiapas, Pueblo Nuevo Soluchistan. Km. 5 Pueblo Nuevo-Jitotol. 1624 msnm 26-VI-2007. 17°08´33´´N 92°53´16´´ W. Bosque Pino. L. Cervantes, G. Ortega, C. Mayorga” (typeface) (2 males, 3 females; CNIN); “ México, Chiapas, Larraizal, km. 22 Bochil-Larraizal, 1,857 msnm. 16°55´04´´ N, 92° 45´36´´W. 26-VI-2007, C. Mayorga, G. Ortega, L. Cervantes” (typeface) (1 female, CNIN); “Chiapas, Rancho Cuducun”, no other data (handwritten) (1 male, MXAL).

Description. Holotype male. Length 9.8 mm, width 4.4 mm. Color reddish yellow on clypeus, anterior half of frons, scape, pedicel, funicle, lateral margins of pronotum, prosternum, center of metasternum, abdomen, and legs; shiny black on antennal club, posterior half of frons, pronotal disc, scutellum , elytra, and mesosternum. Head. Clypeus subtrapezoidal, anterior border curved, briefly raised, and not directed forward; anterior angles widely rounded; clypeal surface rugose with abundant, large punctures. Frontoclypeal suture straight, clearly defined. Frons slightly convex, glabrous, densely punctate; puctures rugose at center, more disperse on lateral and posterior margins. Punctures around eyes scattered. Antennal club slightly longer than the length of all preceding antennomeres combined; lamellar shape semiovate, nearly straight ( Fig. 37 ). Eyes small, ovate, ocular margin dorsally noticeable and setose. Eye canthus thick with glabrous, rounded apex and flattened surface with shallow minute punctures. Maxillary basistipe weakly convex, sparsely punctate; labrum wide and sinuate; labium sinuate, slightly longer than wide; prementum glabrous with irregular, deep pits. Pronotum wider than long, weakly convex; surface with uniformly distributed, deep, medium size, round punctures; lateral borders angled with bulky sides and large, deep lateral pits; posterior angles not raised. Mesoepimera briefly exposed over humeral calli. Space between mesocoxae wide; mesometasternal process stout, but not very long, briefly projecting anteriorly past mesocoxa with wide base and sharply pointed apex directed forward; metasternum covered with numerous wide punctures, sides moderately setiferous; mesial region of metasternum glabrous with deep longitudinal sulcus. Elytra flattened and ovate, striae clearly impressed with nearly continuous rows of large punctures; elytral costae well defined; elytral suture raised on posterior third; brief preapical slope; lateral margins nearly straight with stout, short setae on epipleural area and other slender setae on margin. Epipleural fold narrow, oblique in lateral view, gradually narrowed after metacoxa. Scutellum : nearly longer as wide; lateral margins rounded, apex weakly rounded; surface with uniform, wide, deep punctures. Abdomen: sternites with scattered setae on continuous row of large punctures. Legs: protarsomeres 1–4 short and wide, as wide as protarsomere 5 and as long as it. Protibia stout, progressively widened apically; lateral borders divergent towards apex; external border with proximal denticle short and rounded; distal denticle long, slightly curved ( Fig. 36 ). Mesofemora with a well-defined longitudinal keel and disperse, setiferous punctures. Metafemora without keel. Metatibia with 2 deep transverse keels and spine-like, short setae; apex of metatibia clearly swollen. Metatarsomeres 1–2 longer than tarsomeres 3–5. Genitalia ( Figs. 38–41 ): parameres complex, shorter than the length of tectum, with upper part irregular, narrowed towards apex and weakly upturned; lower part of parameres briefly curved backwards. Basal half of tectum wider than distal half, with outstanding posterolateral calli. Basal piece with long and round, pointed apodema. Spiculum gastrale ( Fig. 40 ) narrow; basal part slightly curved, with uniform width, shorter than lateral sclerites; associated plates small, subovate, with numerous long setae near exterior border.

Allotype female. Length 10.4 mm, width 4.4 mm. Color yellowish red on most of body surface and legs; shiny black on two central spots of pronotal disc, part of epipleural border, and along elytral suture. Antennal club as long as funicle. Epipleural fold more swollen and enlarged medially. Metasternum with shallow longitudinal sulcus. Protibiae and protarsi narrower than in male. Genital plates elongate, subovate, with angled apex and numerous setae on distal half ( Fig. 41 ).

Paratypes (n = 20). Length: 9.0–11.0 mm, width: 4.3–4.5 mm. Color in females vary from orange red to ochre yellow, but two black spots on the pronotum are constant.

Diagnosis. Clypeus subrectangular. Pronotum with uniformly distributed deep, medium round punctures (approximate diameter 0.033 mm). Elytral surface with striae indicated by uniform rows of deep, large punctures; elytral lateral margins without bend. Protarsomeres 1–4 shortened, but slightly wider than protarsomere 5. Protibia stout, progressively widened distally; external border with proximal denticle short and rounded; distal denticle long, oblique. Parameres short and complex, with upper part narrowed towards apex and weakly upturned distally (Table 1).

Etymology. From the Nahuatl indigenous village “ Ixtacomitlan ” in the northern slopes of state of Chiapas, where the first specimens of this species were collected.

Distribution, phenology, and natural history. This species is distributed in the humid slopes of Sierra Norte de Chiapas in Mexico ( Fig. 54 ) between 150–1,860 m in elevation, where cloud forests and pine-oak forests overlaps with tropical rain forest and coffee plantations. Adults are active during June through December. Plant hosts for adults are unknown, and the immature stages remain undescribed.

Remarks. Pachystethus ixtacomitanus is similar to P. matzapatlecus and P. nectoctenus , but may be distinguished from the former because the elytra with the posterior calli prominent, and from the latter because the elytra are clearly punctate instead of nearly smooth. The shape of parameres is also diagnostic (Table 1).

Figures

FIGURE 54. Distribution of species of Pachystethus.

FIGURES 36 – 41. Diagnostic structures in P. ixtacomitanus: 36) right proleg, 37) right antenna, 38) male genitalia dorsal view, 39) male genitalia lateral view, 40) spiculum gastrale, 41) female genital plates. Scale lines 1 mm.

FIGURES 42 – 47. Dorsal view of Pachystethus species: 42 a, b) P. viduus males; 42 c) P. viduus female; 42 d) P. viduus female, lectotype; 43 a) P. nectoctenus male; 43 b) P. nectoctenus female; 44 a) P. crassesculptus male; 44 b) P. crassesculptus female; 45 a, b) P. nutans males; 45 c) P. nu t an s female; 46 a, b) P. matzapatlecus males; 46 c) P. matzapatlecus female; 47 a) P. ixtacomitanus male; 47 b) P. ixtacomitanus female. Scale lines 1 mm.