Neoheteronyx schoutensis, Prokofiev, 2016

Prokofiev, Artem M., 2016, On the Phytophagous Scarabs of the Subfamilies Dynastinae, Rutelinae, and Melolonthinae from the Schouten Islands (Kepulauan Biak), Indonesian Papua (Coleoptera: Scarabaeidae), Species Diversity 21, pp. 71-77 : 75-76

Neoheteronyx schoutensis sp. n.

( Figs 7–10 )

Material. Holotype ( Fig. 7 ), male, Indonesia, Papua, Yapen I. , northern coast, Rosbori village , black light, 13– 14.11.2012, A. M. Prokofiev leg. Paratypes: 1 female, same data as holotype; 3 males, Biak I ., Biak Utar , near Napdori village, 2–3 km from right bank of Air Napdori river, black light, 10–11 (2 specimens) and 18– 19.11.2012, A . M . Prokofiev leg.

Differential diagnosis. The new species is similar to N. insulanus (Moser, 1920) from the Aru Is. in possessing eight-jointed antennae, but differs from the latter species in having pale legs and much coarser, denser, and very regular punctation of the pronotum (punctures are much sparser on the disc than on the sides of the pronotum in N. insulanus ) and a weakly lamellate fifth joint of the antenna. All the other Indonesian and Papuan species of Neoheteronyx except the highly distinctive N. calliseta (see above) have ninejointed antennae.

Holotype. Male. Length 7.2 mm, greatest width 3.0 mm. Pitch-black above, with reddish-brown tint on elytra; dark reddish-brown below; legs testaceous-brown, with apices of tibiae more infuscated and tarsi reddish-brown; punctures on dorsal surface and pygidium with pale bottoms.

Antennae eight-jointed, with three-jointed club; fifth joint with short lamellate process ( Fig. 8 ). Frontal face of clypeus deep, with smoothly convex dorsal margin, and smoothly concave ventral margin; minutely punctured, with uninterrupted transverse row of large setigerous punctures bearing moderately long setae. Sides of clypeus strongly convergent anteriad, with anterior margin almost straight in dorsal view, anterior angles broadly rounded. Dorsal surface of head coarsely and densely punctured; punctures larger on clypeus than on frons and vertex; frontoclypeal suture deep, convex; anterior part of frons impressed along middle twothirds of frontoclypeal suture; 1 moderately short seta sitting on each side at end of ocular canthus and another along inner margin of eye in middle of its anterior third. Eyes large, with posterior margin weakly concave. Labrum deeply concave. Last joint of maxillary palpus fusiform, with ring of sparse setae across its mid-length. Mentum setose in posterior half, with setae shorter but much denser at base.

Pronotum transverse, twice as broad as long, broadest at middle; sides more convergent anteriad than posteriad; anterior angles sharply pointed; posterior angles obtuse; anterior and posterior margins unbordered. Pronotum coarsely, densely, and regularly punctured, with most punctures slightly stretched longitudinally; no pronotal setae. Scutellum finely and irregularly punctured, with rounded tip. Elytra coarsely punctured, punctures umbilicate, interspaces between punctures somewhat rugose, costae indistinct. Elytral epipleura with row of widely spaced short setae along whole length. Thorax finely but conspicuously punctured. Propleura in anterior half densely punctured, with moderately long setae; in posterior half more sparsely punctured, glabrous. Prosternal process absent. Mesosternum densely punctured, punctures setigerous; metasternum less densely punctured, glabrous, except for a few short setae on each side of metasternal disc. Pygidium coarsely but rather sparsely punctured, punctures larger on disc than on sides, interspaces between punctures smooth and shining; apical third of pygidium and sixth abdominal sternite covered densely with long, erect, pale hairs. Abdominal sternites and basis of pygidium sharply and continuously carinate. Abdominal sternites coarsely and rather sparsely punctured, glabrous except for fifth sternite with its transverse row of moderately short, very sparse setae; sternites 5 and 6 abbreviated.

Protibia almost parallel-sided, strongly bidentate, with basal tooth 1.5 times as long as apical point; inner spur long and robust, attached well behind basal tooth; lower surface with medial longitudinal keel. Protibia with 4 longitudinal rows of short setae situated along dorsal mid-line and inner margin, underneath apical and basal teeth; in addition, 3 rather long setae (gradually increasing in length toward apicalmost one) on longitudinal keel on ventral surface. Profemora with patch of setae at base of anterior surface and complete row of short and sparse setae along ventral margin. Procoxae moderately densely pilose in basal half of anterior surface and along lateral margin. Each trochanter with rather short seta at tip (not longer than setae on surface of femora). Middle femora with 3 transverse rows of moderately long, sparse setae on lower surface; middle coxae moderately densely pilose along inner margin; hind femora with 2 widely separated transverse rows of very sparse setae (partially missing) on lower surface and with row of rather dense, soft, moderately long setae along basal half of posterior margin. Posterior margin of hind tibiae with 5+5 spines. Ventral surface of tarsal joints 1–4 multisetose; these joints are not strongly expanded on fore legs and indistinctly expanded on middle legs. Claws symmetrical, simple, with sharp, broad lamina at base on concave side; empodium with dense patch of long setae.

Aedeagus as in Figs 9–10 . Endophallus with strongly sclerotized S-shaped element and patch of short, dense spines.

Female. Length 7.5 mm, greatest width 3.5 mm. Fifth joint of antenna with indistinct tubercle. Last joint of maxillary palpus more elongate than in male, glabrous. Apical tooth of protibia slightly curved, somewhat longer than in male (about twice as long as basal tooth). Tarsal joints 1–4 not dilated, much less setose than in male.

Variation. Males. Length 7.0– 7.5 mm; greatest width 3.0– 3.5 mm. Dark reddish-brown to pitch black above, more brightly reddish-brown below; legs always much paler than ventral side. Setose area on basal part of anterior surface of fore femora somewhat variable in size and shape (as either patch or narrow band).

Etymology. This species is named for its type locality, the Schouten Islands, which themselves are named for their discoverer, the Dutch seafarer Willem Cornelisz Schouten (around 1567–1625).

Figures

Figs 4–12. Neoheteronyx calliseta (4–6), N. schoutensis (7–10), and N. tanythrix (11–12) spp. n., holotypes: 4, 7, 11–dorsal view; 5, 9– aedeagus, lateral view; 6, 10–aedeagus, dorsal view; 8, antenna (weakly lamellate fifth joint arrowed); 12–setosity of middle third of elytral epipleura, dorsal view.Scale bars: 4, 7–9, 11=1mm; 5, 10=0.5mm; 6=0.25mm; 12=0.2mm.