Scaphisoma obscurum, Ivan Löbl & Ryo Ogawa, 2016

Ivan Löbl & Ryo Ogawa, 2016, On the Scaphisomatini (Coleoptera, Staphylinidae, Scaphidiinae) of the Philippines, IV: the genera Sapitia ACHARD and Scaphisoma LEACH, Linzer biologische Beiträge 48 (2), pp. 1339-1492 : 1378-1379

5.2.7.17. Scaphisoma obscurum nov.sp. ( Figs 103, 104 )

T y p e m a t e r i a l: Holotype 6: Philippines, Palawan central, Sabang, sea level, at light 30.XI.1995, Kodada lgt. (MHNG). Paratype: Palawan, Sabang, N. of Mt. St. Paul, 11-13.VII.1977, leg. M. Satô, 1 6 (MHNG).

D e s c r i p t i o n: Length 1.23-1.25 mm, width 0.86-0.88 mm. Head, thorax, elytra and abdominal sternite 1 dark reddish-brown, elytra slightly darkened near apices. Apical abdominal segments light brown to yellowish. Femora light brown, tibiae, tarsi and antennae lighter than femora, yellowish. Pronotum and elytra not microsculptured and not iridescent. Length/width ratio of antennomeres as: III 12/8: IV 20/6: V 38/7: VI 45/8: VII 53/14: VIII 49/9: IX 53/13: X 52/12: XI 65/13. Pronotum very finely and densely punctate, with lateral margins evenly rounded, lateral margin carinae not visible in dorsal view, lateral striae impunctate. Scutellum completely covered by pronotal lobe. Elytra not flattened, with lateral margin carinae entirely visible in dorsal view, apical margins rounded, inner apical angles not prominent, situated about in level with outer angles; sutural margin raised except near base, sutural striae fairly deep, hardly bent at base, not extending along basal margin, slightly converging apically, very finely punctate; adsutural areas narrow, flat, each with single row of very fine punctures, lateral striae distinctly punctate. Elytral disc with punctation very fine, similar to that on pronotum on large humeral area and posterior lateral mid-length along lateral margins. Punctation conspicuously coarse and very dense on inner anterior and middle parts of elytra, punctures there well delimited, to part larger than puncture intervals, becoming gradually finer and sparser posterior middle third of elytra. Hind wings fully developed. Hypomera and mesanepisterna smooth. Mesepimera about as long as intervals to mesocoxae, four times as long as wide. Median part of metaventrite flattened, without impressions, coarsely and densely punctate, with punctures to part about as large as puncture intervals, smooth between metacoxae; lateral parts of metaventrite with strigulate microsculpture, punctation extremely fine and sparse; antecoxal puncture rows absent. Submesocoxal areas 0.04 mm, somewhat less than half of intervals to metacoxae, submesocoxal lines convex, finely punctate, punctures not extended by striae. Metanepisternum flat, weakly narrowed anteriad, inner margin straight in middle section, rounded near angles, suture deep. Tibiae straight. Abdomen with strigulate microsculpture, very finely punctate. Abdominal sternite 1 with submetacoxal areas 0.05 mm, about as half of intervals to apical margin, submetacoxal lines strongly convex, distinctly punctate.

M a l e: Protarsomeres 1 to 3 weakly widened. Aedeagus ( Figs 103, 104 ) 0.45- 0.47 mm long, symmetrical, with basal bulb weakly sclerotized. Basal bulb comparatively large. Articular processes small, not prominent. Apical process of median lobe simple, shorter than basal bulb, strongly inflexed, subparallel and with truncate apex in dorsal view, subcylindrical and strongly inflexed, with acute tip and oblique apical margin in lateral view. Parameres gradually narrowed to apical third and moderately curved in dorsal view, almost evenly wide between bases apical third in lateral view, without membranous inner margin. Internal sac simple, without flagellum or sclerotized pieces, with very fine scale-like structures, its apical part excepted.

E t y m o l o g y: The species epithet is a Latin adjective meaning dark.

Comparative notes: This species may be confused with S. subgracile because of its conspicuous elytral punctation. It differs notably from the latter by the elytra darkened apically, the distinct mesepimera, the microsculptured metaventrite, the abdomen with smaller submetacoxal areas, and the length/width ratios of the antennomeres. The shape of the apex of the median lobe of S. obscurum is diagnostic.

Figures

Figs 101 - 107: Aedeagi of Scaphisoma in dorsal and lateral views; (101, 102), S. nabiluanum nov. sp., scale = 0.1 mm; (103, 104), S. obscurum nov. sp., scale = 0.1 mm; (105, 106), S. sagax nov. sp., scale 0.1 mm; (107), ditto, internal sac, scale = 0.05 mm.