Scaphisoma borneense Pic, 1916

Löbl, Ivan, 2015, Notes on Scaphisoma of Kalimantan (Coleoptera: Staphylinidae: Scaphidiinae), Acta Entomologica Musei Nationalis Pragae 55 (1), pp. 129-144 : 131-132

Scaphisoma borneense Pic, 1916

( Figs 1–3 )

Scaphosoma borneense Pic, 1916c: 7 .

Type locality. Indonesia, Kalimantan, Martapura .

Type material examined. LECTOTYPE (by present designation):♂, ‘Martapoera Z. O.Borneo Doherty VI. VII [printed] / type [handwritten by Pic] / TYPE [red, printed] / Scaphosoma Pic [handwritten by Pic] / borneense Pic [handwritten by Pic] / Lectotype Scaphisoma borneense Pic des. Löbl, 2014’ ( MNHN).

Redescription. Length 1.90 mm, width 1.37 mm. Head, thorax, hypomera excepted, elytra and abdominal ventrite 1 to 4 uniformly reddish-brown, femora and tibiae slightly lighter, hypomera, apical abdominal segments, tarsi and antennae distinctly lighter, almost yellowish. Pronotum and elytra lacking microsculpture. Antennae with length/width ratio of antennomeres as follows: III 15/8: IV 47/6: V 63/7: VI 54/8: VII 61/13: IX 55/12: X: 55/13: XI 73/12 (antennomere VIII missing). Pronotum with lateral margins rounded, lateral margin carinae visible in dorsal view, discal punctation very fine and sparse. Point of scutellum exposed. Elytra with lateral margin carinae exposed in dorsal view, apical margins slightly rounded, inner apical angle not prominent, situated posterior level of outer angles, sutural margin raised, sutural striae fairly deep, shortened, starting about 0.35 mm posterior tip of scutellum, slightly converging apically, adsutural areas slightly roof-like raised, combined 0.14 wide at proximal end, with single row of coarse punctures. Elytral punctation coarse and dense, punctures well delimited, puncture diameters mostly about half to as large as puncture intervals. Hypomera not microsculptured, very finely punctate. Mesepimeres almost as long as interval to mesocoxae and 6 times as long as wide. Metaventrite convex in middle, with two apicomedian impressions not clearly delimited, bearing a few fairly coarse punctures. Antecoxal puncture lines present, impressed, consisting of fine punctures. Remaining surface of metaventrite uniformly and very finely punctate, with punctures hardly visible at 100× magnification, fairly coarse punctures margining submesocoxal lines excepted. Median part of metaventrite not microsculptured, lateral parts with strigulate microsculpture. Submesocoxal lines convex, submesocoxal areas 0.04 mm long, as fifth of interval to metacoxae. Metanepisterna slightly convex, 0.13 mm wide, moderately narrowed anteriad, with inner suture weakly rounded, impressed below level of metaventrite. Protibiae and metatibiae straight, mesotibiae curved. Abdomen with strigulate microsculpture. Ventrite 1 very finely and sparsely punctate, except on basomedian area bearing few fairly coarse punctures; submetaxocal lines convex, submetaxocal areas 0.05 mm long, about as fourth of interval to apical margin of ventrite.

Male characters. Segments 1 and 2 of protarsi and mesotarsi strongly widened, segments 1 almost as wide as the apices of tibiae. Segments 3 of protarsi and mesotarsi weakly widened. Abdominal ventrite 6 with apical lobe large, about 0.15 mm long, truncate apically. Aedeagus ( Figs 1–3 ) about 1.00 mm long. Median lobe with basal bulb strongly sclerotized at apical side, almost membranous proximally. Dorsal branch of apical process tapering, at base widened and weakly sclerotized. Ventral branch of apical process oblique and truncate at apex in dorsal view, sinuate in lateral view, with minute apical denticle and very fine subapical granulation on ventral side. Internal sac with complex denticulate and spinose structures, sclerotized spines and lobes.

Differential diagnosis. The species is a member of the S. tricolor group, and fairly similar to S. chujoi Löbl, 1982 from Sarawak (see LÖBL 1982). It may be readily distinguished from the latter, and other species possessing a basal bulb of the median lobe that is expanded apicodorsally, by the truncate apex of the ventral branch of the apical process of the median lobe (in dorsal view), which is very finely granulate on its ventral side (in lateral view).

Comments. The antennae were broken off and the antennomeres III to VII, IX to XI, and X and XI were found in glue below the specimen. They are now mounted on a slide. Both antennomeres VIII are missing. In addition, the proximal end of the basal bulb of the aedeagus is damaged.

Distribution. Indonesia (Kalimantan).

Figures

Figs 1–5. Aedeagi of Scaphisoma: S. borneense Pic, 1916, internal sac extruded, in dorsal view (1), in lateral view (2), in ventral branch of apical process in lateral view (3). S. mindanaosum Pic, 1926, aedeagus in lateral view (4), paramere and apical process of median lobe in lateral view (5). Figs 1, 2 and 4: scale bars = 0.2 mm, Figs 3 and 5: scale bars = 0.1 mm.