Pachystethus crassesculptus Bates 1888, new combination
Creators: name: Ramírez-Ponce, Andrés
name: Morón, Miguel Angel
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Rutelidae
Pachystethus
Pachystethus crassesculptus

description: Pachystethus crassesculptus (Bates, 1888) new combination
(Figs. 8–13, 44 a,b, 50)
Anomala vidua var. crassesculpta Bates, 1888: 406
Type specimens. Male and female syntypes examined, deposited in NHM. Type locality: “Chimaltenango, Guatemala ”
Type material revised (1 male lectoype, 1 female paralectotype; NHM) labeled: lectotype male: a) “ GUATEMALA: Chimaltenango, Conradt, B.C.A.Col.II (2)” (typeface), b) “ Pachystethus crassesculptus (Bates, 1888) LECTOTYPE male Ramírez-Ponce y Morón des. 2011” (typeface). 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: a) “ GUATEMALA: Chimaltenango, Conradt, B.C.A.Col.II (2)” (typeface), b) “ Pachyststhus crassesculptus (Bates, 1888) PARALECTOTYPE female Ramírez-Ponce y Morón des. 2011” (typeface). Additional material revised (21 males, 9 females; CNIN, MXAL, ZMHB) labeled: Guatemala / L. Conradt S. (18 males and 4 females, ZMHB) (typeface); Guatemala / Tumbador Riedel S. 4.12 (1 male and 3 females, ZMHB) (typeface); Guatemala (1 female, ZMHB); MEXICO, Chiapas, Tapachula, Unión Roja, La Boquilla, 22-IX- 82, 550 m, planta silvestre, R. Terrón (2 males, MXAL) (typeface); MEXICO, Chiapas, 9 km al sur de Union Juárez, Puente Shujukal. 21-IV-83. E. Barrera (handwritten) (1 female, CNIN) (typeface).
Redescription. Male (n = 21). Length 10.7–11.0 mm, width 3.9–4.1 mm. Color reddish yellow on clypeus, anterior half of frons, scape, pedicel, funicle, lateral margins of pronotum, abdomen, pygidium, femora, tibiae and tarsi; shiny black on antennal club, posterior half of frons, disc of pronotum, scutellum, and elytra. Head: clypeus subtrapezoidal, clearly wider than long; anterior border straight, slightly upturned and directed forward; anterior angles rounded; clypeal surface with irregular, dense, large punctures. Frontoclypeal suture well defined, straight. Frons nearly flattened, densely and irregularly rugopunctate at center, with scattered large punctures along lateral and posterior margins. Punctures around eyes are more disperse and smaller than in frons, and are combined with scarce, long setae. Antennal club nearly as long as all preceding antennomeres combined; lamellar shape ovate, straight (Fig. 9). Eyes small, ovate, ocular margin noticeable and exposed dorsally. Eye canthus thick with glabrous, rounded apex and flattened surface; surface with irregular punctures. Maxillary basistipe flat with irregular, wide punctation; labrum wide and sinuate; labium sinuate, slightly longer than wide, with irregular rugopunctate; prementum setose. Pronotum wider than long, slightly convex; surface with a moderate number of shallow, small sized, circular punctures; lateral borders nearly straight, weakly curved, with bulky sides and lateral pits; posterior angles raised. Mesoepimera scarcely exposed over humeral calli. Space between mesocoxae wide, meso-metasternal process long, projecting anteriorly past mesocoxa but not reaching procoxae; with wide, rounded apex directed downward; metasternum densely punctate, sides uniformly setiferous, mesial region glabrous and longitudinally sulcate. Elytra flattened, short, ovate; striae deeply impressed with coarse large punctures; elytral costae discrete, suture raised towards posterior half; brief preapical slope; lateral margins nearly straight (without wide bend at the end of epipleural fold) with sparse, short setae along apical third. Epipleural fold sharp in lateral view, gradually narrowed after metacoxa. Scutellum slightly wider than long; lateral margins rounded, apex acute, surface irregularly punctate. Abdomen sternites scarcely setiferous, each with one discontinuous row of setiferous punctures near posterior border and wide, weakly punctate, glabrous central area. Legs: protarsomeres 1–4 short, slightly wider and longer than protarsomere 5. Protibia stout, slightly widened towards apex; lateral borders nearly parallel; external border with proximal denticle wide and acute; distal denticle long, oblique (Fig. 8). Mesofemora with a well-defined longitudinal keel, with long setae. Metafemora without longitudinal keel. Metatibia with scarce, setiferous, large punctures. Metatarsomeres 1–2 large, longer than tarsomeres 3–4. Genitalia (Figs. 10–12): parameres shorter than the length of tectum, with upper part slightly concave and smooth, gradually narrowed and upturned towards apex; lower part of parameres slightly curved backwards. Basal half of tectum clearly wider than distal half, with outstanding posterolateral calli. Basal piece with long, acute apodema. Spiculum gastrale (Fig. 12) narrow, basal part straight, slightly widened towards apex, slightly shorter than lateral sclerites; associated plates subtriangular with widely rounded apex, irregular upper inner margin and long setae on entire surface of exterior border. Female (n = 10). Length 11.2 mm, width 4.2 mm. Color shiny reddish yellow or ochreous yellow on nearly entire body, except antennal club, two central-lateral spots on pronotal disc, and preapical elytral borders that are shiny black. Body stouter than in male; elytral striae marked with black, deep punctures; epipleural fold swollen; protibiae and protarsi not swollen; metatarsomeres wider than in male. Antennal club slightly longer than the length of the pedicel and funicle combined. Genital plates medium sized, elongate with round, convergent apex; regular inner borders with long setae on distal part (Fig. 13).
Variation (n = 30). Extension of the black coloration in specimens with a contrasting bicolored pattern is variable mainly in the pronotum and head. Areas of the body with red color may be significantly more darkened (lateral borders on pronotum, frons, clypeus, abdomen, sternum, and legs). Although none were seen, some individuals are probably completely black in color. In one female, the distal part of the elytral interstriae was not prominent.
Diagnosis. Clypeus subtrapezoidal. Pronotum with small size (approximate diameter 0.025 mm), circular, shallow punctures. Elytral striae deeply indicated with punctures; posterior calli and distal part of interstriae prominent; lateral margins without bend. Protarsomeres 1–4 wider and shorter than distal protarsomere. Protibia slightly wider towards apex with lateral borders nearly parallel. Parameres large and complex, with dorsal surface smooth and convex (Table 1).
Etymology. Although not cited in the original description, the name is derived from Latin terms crassus (thick, heavy) and sculptum (engraving, texture) (Jaeger 1978), meaning heavy texture, probably in reference to the elytral surface.
Distribution, phenology, and natural history. This species is distributed along the humid slopes of Sierra Madre de Chiapas in Mexico, and Sierra Madre de Guatemala (Fig. 54), between 550–1750 m in elevation, and from the southeast of state of Chiapas, Mexico (near Tapachula and Union Juárez) to south Guatemala (El Tumbador and Chimaltenango). Adults are active in September. No plants are recorded as hosts for adults, and the immature stages remain undescribed.
Remarks. In the supplement for Lamellicornia and Pectinicornia Bates (1888: 406) described this taxon as a variety of Anomala vidua, arguing that it is a local modification and pointed out that the most distinct characters are the deep sculpture on dorsal surfaces and pale color in the tarsi of both sexes. Additional important differences include body shape, legs, ventral vestiture, body color, and in the form of the genitalia that support this as a valid species.
description: Published as part of 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), pp. 1-24 in Zootaxa 3394 on pages 7-9, DOI: 10.5281/zenodo.210542