Engertia setifera ( Moser, 1913 )

Prokofiev, Artem M., 2015, A male of Engertia setifera (Coleoptera: Scarabaeidae: Melolonthinae) from Seram Island, Indonesia, Baltic Journal of Coleopterology 15 (1), pp. 25-28 : 25-27

Engertia setifera ( Moser, 1913)

( Figs 1-4 )

Phila setifera : Moser, 1913: 284 (original description).

Type material. The holotype and a single previously known specimen (female) is presumably housed in a collection of the Museum für Naturkunde, Berlin [not studied].

Material examined. 1 male ( Fig. 1 ), Indonesia, Maluku prov., Seram I., Waipia district , ~ 40 km N Elpa Putih, on light, 17- 20.11.2011, leg. A.M. Prokofiev.

Description of male. Length 17 mm, greatest width 6.5 mm. Dark-reddish to reddish-brown, elytra somewhat paler than the rest of body; scales and pilosity pale yellow, hairs on pro-, meso- and metasterna, fore and middle legs and hind coxae pale orange.

Clypeus pentagonal, with anterior margin bluntly pointed, surface roughly but not densely and somewhat unevenly punctured; punctures setigerous, setae slightly broadened (scale-like). Fronto-clypeal suture conspicuous, slightly carinate, angularly concave in the middle, where frons being somewhat longitudinally carinate on a short distance. Frons and vertex roughly rugoso-punctate along the fronto-clypeal suture and the inner margins of the eyes, rather deeply but sparsely and unevenly punctured mesially to glabrous along the mid-length; punctures setigerous. There are long semi-erect not dense hairs in anterior part of frons between eyes and fronto-clypeal suture, very dense patches of lanceolate scales on each side along the inner sides of eyes and at the outer thirds of posterior half of vertex, and few sparse scale-like setae in the middle of the dorsal surface of head; ocular canthus with a brushlike patch of moderately long hairs and few scale-like setae. Antennae 10-jointed, with 5- jointed club, which is almost equal to the length of antenna; 6 th and 10 th joints indistinctly shorter than the intermediate ones; 5 th joint with a short anterior process; club joints strongly shagreened, funicle joints glabrous. Last joint of maxillary palpi elongately fusiform, very narrow, with a long and narrow impression on its outer side. Labrum very scarcely bilobed, densely setose but lacking scales; mentum deeply concave anteriorly.

Pronotum distinctly narrower than the base of elytra, 1.6 times as broad as long, broadest in middle; sides more convergent anteriad than posteriad; sides straight anteriad, but weakly sinuate before posterior angles; anterior angles almost straight; posterior angles obtuse, shortly rounded but conspicuous. Anterior margin of pronotum bisinuate, posterior margin strongly convex in its middle third, weakly sinuate in lateral thirds; all sides of pronotum unbordered. Anterior margin of pronotum possesses the r ath er lon g ver y den se hair s, somewh at shortened toward middle; sides of pronotum with a row of moderately long sparse hairs. Pronotum finely and very unevenly punctured, punctures setigerous; surface of pronotum with a pair of very indistinct small impressions on each side just laterad from mid-length and a pair of larger and more pronounced (especially posteriormost one) impressions on middistance from mid-length to side margin of pronotum. There are rather dense patches of lanceolate scales in these impressions; lateral thirds of posterior margin of pronotum are bordered with the moderately densely sitting lanceolate scales; sides of pronotum bear a narrow band of scale-like setae; in the rest, surface of pronotum is extremely sparsely covered by scale-like setae and few lanceolate scales. Scutellum broadly rounded apically, glabrous except 2-4 rows of setigerous punctures bearing scale-like setae along its outer margin. Elytra with 5 distinct costae, of which 2 nd and 3 rd ones being most pronounced; basis of elytron with a swelled border. Interspaces shallowly, unevenly and unequally punctured; punctures setigerous; each puncture being much darker (almost black) than surface; costae completely glabrous. Interspaces and the apical border of elytr a ar e covered with moderately sparse scale-like setae, which are slightly broader in discal interspaces rather than along sides. Pygidium moderately densely covered by moderately short adpressed hairs and with very sparse and small elongately ovoid scales. Sterna densely covered with rather long adpressed hairs; legs hairy only except few narrows scales near apical tips on lower surface of fore and middle femora, sparse lanceolate scales on lower surface of hind femora, and rare setiform scales on hind tibiae. Abdomen moderately densely covered with moderately long adpressed hairs and sparse lanceolate scales not concentrated along the mid-line.

Protibiae unidentate; spur short and thick; middle and hind tibiae very gracile; apex of hind tibiae with 12 distant bristles. Tarsal joints 1-4 shortened, especially of fore tarsi; 1 st joint of hind tarsi 1.5 times longer than the second one. Claws bidentate, with lower lobe slightly closer to the upper one than to the base and almost parallel to the upper one, distinctly shorter but as broad as the latter.

Aedeagus as on figs 2, 3; ventral margin of parameres distinctly angulate before tip (figs 2, 4).

Female. See Moser (1913: 284). Moser described the female as: “nigra,…, elytris pedibusque fuscis…flabello feminae parvo, 4- articulato…prothorace…punctis setas albas fer entibus… 18 mm ”; in the other details reported in the original description, the type female is identical to the male described above.

Diagnosis. This species differs from the other Engertia in the presence mostly of setae instead of scales dorsally and in a very weak scalation ventrally. It is most similar to E. amboinae (Brenske, 1897) and E. papuana ( Moser, 1913) in the presence of 5-jointed club in the males, in the shape of the clypeus and disposition of the scale/setae patches on the dorsal surface, and in the shape of the aedeagus. In contrast to the aforementioned species, the labrum of E. setifera is very indistinctly bilobed and not scaled, the sterna are totally unscaled and covered with the pale-orange (vs. grayishwhite) hairs, the pygidium is setose and the abdomen is very sparsely scaled, mostly on the sides. Furthermore, it differs from E. papuana , but similar to E. amboinae in the shape of the pronotum, which is broadest in the middle (vs. clearly before the middle in E. papuana ). The parameres are very similar to E. papuana in the distinctly angulate ventral margin (smooth in E. amboinae , see Keith, 2006: fig. 2), but their tips are somewhat less broad and rounded in profile (see figs 4 and 5).

Figures

Figs 1-5. Engertia setifera (1-4) and E. papuana, New Guinea: Sentani (5), males: 1 – dorsal view; 2-5 – aedeagus: 2 – lateral view; 3 – dorsal view; 4, 5 – tips of parameres, lateral view. Scale bars: 1 – 3 mm; 2, 3 – 0.5 mm (common bar); 4, 5 – 0.25 mm (common bar).