Stenocrates lissothorax Ratcliffe and Figueroa, 2018

Ratcliffe, Brett C. & Figueroa, Luis, 2018, Description of a New Species of Stenocrates Burmeister (Coleoptera: Scarabaeidae: Dynastinae: Cyclocephalini) from Peru, The Coleopterists Bulletin 72 (4), pp. 797-800 : 799-800

Stenocrates lissothorax Ratcliffe and Figueroa , new species

( Figs. 1–4 , 6–7 ) Zoobank.org/ urn:lsid:zoobank.org:act:11DE5A8B-8DCC-4D40-B73B-1798A6AF2FF8

Type Material. Holotype labeled “ PERU: Amazonas: Bongara, / Corosha, Beirut , Rocota trail, / S05°49´4.4´´ W77°49´19.1´´, 2004m / 19.XI.2016. leg. M. Alvarado, L. / Breitkreuz, J. Thomas, light trap, / PERU 1ABT16010 // bar code SEMC1549291 / KUNHM-ENT ” and with our red holotype label . Allotype with same data and “bar code SEMC1549264 / KUNHM-ENT ” and with our red allotype label. Two male and three female paratypes with same data and bar codes of “ SEMC1549265 / KUNHM-ENT ”, “ SEMC1549266 / KUNHM-ENT ”, “ SEMC1549268 / KUNHM-ENT ”, “ SEMC1549279 / KUNHM-ENT ”, “ SEMC1549267 / KUNHM-ENT ” and our yellow paratype labels . Holotype and allotype deposited at the Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Lima, Peru ; three paratypes (one male, two females) deposited at the Snow Entomology Museum, University of Kansas, Lawrence, KS, USA, and two paratypes (one male, one female) in the B. C. Ratcliffe collection (Lincoln, NE, USA.

Description. Holotype. Male ( Fig. 1 ). Length 17.2 mm; width across humeri 7.8 mm. Color black. Head: Frons smooth, shiny, with small, indistinct, roughened field of shallow punctures at center apex. Frontoclypeal suture distinctly impressed, arcuate, lacking carinulate ridge in front of suture. Clypeus coarsely, completely, transversely rugose; apex subtruncate (feebly convex) (as in Fig. 3 ). Interocular width equals 2.5 transverse eye diameters.

Antenna with 10 antennomeres, club subequal in length to antennomeres 2–7. Pronotum: Surface shiny, completely smooth, with indistinct, sparse micropunctures (as in Fig. 3 ). Lateral margins with thick marginal bead, base lacking marginal bead. Elytra: Surface shiny, with punctate sutural stria and 2 pairs of distinct discal striae and 1 pair of striae behind humerus; each stria comprised of large, deep, closely adjacent punctures. First broad interval with single, irregular row of similar punctures, second broad interval lacking punctures. Pygidium: Surface shiny, completely and moderately densely punctate, punctures less dense on apical third; punctures moderately large, glabrous. In lateral view, surface weakly convex. Legs: Protibia tridentate, basal tooth slightly removed from other teeth. Metatarsus shorter than metatibia. Venter: Prosternal process long, thick; in lateral view, columnar, flared posteriorly at base, apex narrowly rounded into 2 small prominences, each prominence with several long setae; in ventral view, apex a subtriangular cone. Parameres: Form widest just above middle, lateral margins flared above apices, apices stout and curving away from one another ( Fig. 4 ).

Allotype. Female ( Fig. 2 ). Length 19.6 mm; width across humeri 9.5 mm. The allotype does not differ significantly from the holotype.

Variation. Males (two paratypes): Length 17.0– 17.7 mm; width across humeri 8.0– 8.2 mm. The male paratypes do not differ significantly from the holotype. Females (three paratypes): Length 18.3– 20.0 mm; width across humeri 8.4–9.3 mm. The female paratypes do not differ significantly from the allotype.

Etymology. The epithet is derived from the Greek lissos meaning smooth or polished and the Greek thorax referring to a breastplate. The specific epithet is used as a noun in apposition and means "the smooth thorax" in reference to the completely smooth pronotum of this species.

Distribution. Stenocrates lissothorax is known only from Amazonian Peru ( Fig. 6 ).

Locality Records. PERU (7). AMAZONAS REGION (7): Bongara Province, Corosha District, Beirut Municipality, Rocota trail.

Temporal Distribution. November (7).

Diagnosis. The form of the parameres is essential for distinguishing species of Stenocrates because their external body morphology is, with few exceptions, so similar. The parameres of S. lissothorax are unique but vaguely resemble those of Stenocrates holomelanus (Germar, 1824) (compare Figs. 4 and 5 ). However, S. holomelanus is small (12–15 mm), whereas S. lissothorax is larger (17–20 mm). In addition, the surface of the pronotum is entirely smooth in S. lissothorax (hence its specific epithet) but variably punctate in all other species of Stenocrates known from Peru.

Natural History. The specimens were taken at lights at 2,000 m in an area of evergreen montane forests ( Fig. 7 ). As with virtually all species of Stenocrates , nothing is known of the life history of S. lissothorax .

Remarks. Stenocrates species recorded from Peru are Stenocrates bicarinatus Robinson, 1948 ; Stenocrates carbo Prell, 1937 ; Stenocrates celatus Prell, 1937 ; Stenocrates clipeatus Endrödi 1966 ; Stenocrates cognatus Endrödi, 1966 ; Stenocrates cultor Burmeister, 1847 ; Stenocrates haackae Ratcliffe, 1977 ; S. holomelanus ; S. lissothorax ; Stenocrates mimeomus Ratcliffe, 2015 ; Stenocrates minutus Endrödi, 1966 ; Stenocrates nasutus Dechambre, 1979 ; Stenocrates omissus Endrödi, 1966 ; Stenocrates popei Endrödi, 1971 ; and Stenocrates serendipitus Ratcliffe, 2015 .

Figures

Figs. 1–3. Stenocrates lissothorax. 1) Male holotype; 2) Female allotype; 3) Female paratype, head and pronotum.

Figs. 4–5. Stenocrates species, parameres. 4) S. lissothorax; 5) S. holomelanus.

Fig. 6. Stenocrates lissothorax distribution map.

Fig. 7. Stenocrates lissothorax type locality near Beirut municipality, Amazonas, Peru. Photograph by Laura Breitkreuz (University of Kansas).