Pachystethus nutans ( Bates, 1888 ) Bates, 1888

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 : 11-13

Pachystethus nutans ( Bates, 1888) new combination

( Figs. 14–19 , 45 a–c, 51)

Anomala nutans Bates, 1888: 246

Type specimens. Male and female syntypes examined, deposited in NHM. Type locality: “Juquila, Mexico ”

Type material revised (1 male lectotype, 1 female paralectotype: NHM) labeled: lectotype male: a) “MEX- ICO: [Oaxaca] Juquila. Salle Coll. B. C. A., Coll., II (2)” (typeface), b) “ Pachyststhus nutans ( Bates, 1888) LEC- TOTYPE male Ramírez-Ponce y Morón det. 2011” (typeface; NHM). Lectotype here designated for the taxonomic purpose to preserve nomenclatural stability by selecting a single specimen as the name-bearing type of the name of this taxon. Paralectotype female: “ MEXICO: [Oaxaca] Juquila. Salle Coll. B. C. A., Coll., II (2)” (typeface), b) “ Pachystethus nutans ( Bates, 1888) PARALECTOTYPE female Ramírez-Ponce y Morón des. 2011” (typeface; NHM). Additional material revised (3 males; CNIN, DDC, MXAL) labeled: Mexico: Oaxaca, 6 km SE Lachao, El Polvorín, 1900 m, 27-V-2006, D. Curoe (typeface) (1 male, DCC); a) Anomala nutans Deyz Veracruz (typeface), b) “ Anomala nutans Bat. ” (handwritten), c) “1670” (typeface), d) “Ex-colección Eugenio Dugés” (typeface) (1 male, CNIN); a) “ Mexico, Jalapa, Hoge”, b) “ Spilota nutans Bts. ” (typeface) (1 male, MXAL).

Redescription. Male (n = 4). Length 9.1–9.6 mm, width 4.2 mm. Color reddish yellow on scape, pedicel, funicle, lateral margins of pronotum and elytra; dark red on clypeal margins, apexes of femora, tibiae, distal tarsi, and claws; shiny black on antennal club, frons, disc of pronotum, scutelum, elytral suture, and legs (except their apices). Head. Clypeus subrectangular, clearly wider than long; anterior border straight, strongly upturned and not directed forward, anterior angles rounded; clypeal surface with irregular, dense, deep, large punctures. Frontoclypeal suture straight, partially hidden by punctures. Frons flattened, glabrous, densely rugopunctate, punctures irregularly elongate and fused at center, more disperse on lateral and posterior margins. Punctures around eyes deep but not coalescent, with some long setae. Antennal club longer than the length of all preceding antennomeres combined; lamellar shape ovate, curved inward ( Fig. 15 ). Eyes medium size, ovate; ocular margin noticeable and setose. Eye canthus thick with glabrous and rounded apex, raised surface, irregular deep punctures. Maxillary basistipe convex, with irregular wide punctation; labrum wide and sinuate; labium sinuate, slightly longer than wide, irregularly punctate; prementum setose. Pronotum wider than long, moderately convex; surface with abundant deep, large, elongate punctures; lateral borders rounded, with bulky sides and weak lateral pits; posterior angles raised. Mesoepimera hidden under humeral calli. Space between mesocoxae wide; mesometasternal process long, projecting anteriorly past mesocoxa but do not reach procoxae with wide rounded, apex directed downward; metasternum moderately and sparsely punctate, sides uniformly setiferous, mesial region glabrous with weak longitudinal sulcus. Elytra convex, wide, ovate; striae deeply impressed with uniform, continuous, large punctures; elytral costae absent, suture raised towards posterior half; wide preapical slope; lateral margins with wide notch posterior to the end of epipleural fold ( Fig. 51 ) and discontinuous row of sparse, short setae along entire length. Epipleural fold wide, uniformly swollen in lateral view, gradually narrowed after metacoxa. Scutellum : slightly longer than wide; lateral margins angled, apex acute; surface with sparse, deep, large punctures. Abdomen: sternites nearly completely covered with setae and moderate punctation. Legs: protarsomeres 1–4 shortened, slightly wider than and as long as protarsomere 5. Protibia stout; lateral borders convergent towards apex; external border with proximal denticle short, acute; distal denticle long, curved ( Fig. 14 ). Mesofemora with a well-defined longitudinal keel, with long setae. Metafemora with incomplete setiferous punctures, transverse keel. Metatibia with scattered, setiferous, deep, large punctures; middle and apex of metatibia clearly swollen. Metatarsomeres 1–2 short, as long as metatarsomeres 3–5. Genitalia ( Figs. 16–18 ): parameres simple, shorter than the length of tectum, with upper part concave and smooth, strongly narrowed towards apex; lower part of parameres curved backwards. Basal half of tectum as wide as distal half, with outstanding posterolateral calli. Basal piece with long, curved, sharply pointed apodema. Spiculum gastrale ( Fig. 18 ) narrow, basal part slightly bend, briefly shorter than lateral sclerites; associated plates large, subquadrangular, with irregular apical margin clearly sinuated, and long setae near the border.

Female (n = 1). Length 9.5 mm, width 4.2 mm. Color bright reddish yellow on clypeus, anterior half of frons, scape, pedicel, funicle, lateral margins of pronotum, elytra, coxae, trochanter, and femora; reddish brown on protibiae, protarsi, mesotarsi, and tarsal claws of all legs; shiny black on antennal club, posterior half of frons, pronotal disc, scutellum , abdomen, apices of femora, tibiae, and metatarsi. Antennal club as long as the length of the scape, pedicel, funicle combined. Body similar to male; elytral striae deep marked, with uniform large punctures; epipleural fold swollen; protibiae and protarsi narrower than in male, protarsomeres 1–4 slightly longer than in male; metatarsomeres wider than in male. Genital plates large, elongate, subtriangular, with acute apex; irregular inner and outer borders with long setae over nearly entire surface ( Fig. 19 ).

Variation. The punctation on pronotum and the black color on elytral suture can be more stressed and lighter respectively. Some males are completely black.

Diagnosis. Clypeus subrectangular, anterior margin strongly upturned. Pronotum with elongate, large sized (approximate size 0.035 x 0.072 mm), deep punctures. Elytral striae deeply indicated with punctures; lateral margins with wide, central notch. Protarsomeres 1–4 shortened, slightly wider than protarsomere 5 but with equal length. Protibia stout, lateral borders convergent towards apex. Parameres short and simple, with upper part concave and smooth, strongly narrowed towards apex (Table 1).

Etymology. Although not cited in the original description, the name is derived from the Latin term nutans (nodding, unsteady) ( Jaeger 1978), perhaps indicating that the author was uncertain of the species. The name was assigned to specimens in the collection of Sallé ( Bates 1888: 247).

Distribution, phenology, and natural history. This species is distributed on the slopes of Sierra de Miahuatlan, Oaxaca, between 1300–1900 m in elevation ( Fig. 54 ), where pine forests and cloud forests are mixed with secondary vegetation. Adults are active during May. No plants have been recorded as hosts for adults, and the immature stages remain undescribed.

Remarks. The record from “Jalapa, Hoge” is in doubt. It may correspond with the well-known confusion of some samples collected by Höge in the southern Pacific slopes and wrongly labeled as “Jalapa,” that many authors interpreted as Jalapa de Enriquez, Veracruz.

Figures

FIGURE 54. Distribution of species of Pachystethus.

FIGURES 14 – 19. Diagnostic structures in P. nu t an s. 14) right proleg, 15) right antenna, 16) male genitalia in dorsal view, 17) male genitalia in lateral view, 18) spiculum gastrale, 19) 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.

FIGURES 48 – 53. Lateral view of Pachystethus species: 48) P. viduus a) male, b) female; 49) P. nectoctenus a) male, b) female; 50) P. crassesculptus male; 51) P. n u t a n s male; 52) P. matzapatlecus male; 53) P. ixtacomitanus male. Scale lines 1 mm.