Scaphisoma ancora, Löbl, 2018

Löbl, Ivan, 2018, A review of Scaphisomatini from Sulawesi, with descriptions of ten new species (Coleoptera: Staphylinidae: Scaphidiinae), Acta Entomologica Musei Nationalis Pragae 58 (1), pp. 151-165 : 153

publication ID 10.2478/aemnp-2018-0013

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scientific name

Scaphisoma ancora

sp. nov.

Scaphisoma ancora sp. nov.

( Figs 6–12 View Figs 1–19. 1–5 , 50, 51 View Figs 50–53 )

Type locality. Indonesia, Central Sulawesi, Palu District, Taman Nasional Lore Lindu [National Park], environs of Wuasa, 1°24,445 ′ S, 120°18,801 ′ E.

Type material. HOLOTYPE: ( NMPC), SULAWESI, Palu dist. / Lore Lindu N.P. , Wuasa env., / 1°24,445’S, 20°18,801’E [sic!], / 15.viii. 2013, V.Hula lgt. GoogleMaps PARATYPES: 5 6 ♀♀ ( NMPC, MHNG), with the same data as the holotype. GoogleMaps

Description. Length 1.64–1.80 mm, width 1.05–1.10 mm. Head, pronotum and elytra reddish-brown, abdomen and appendages lighter, ochreous. Antennae long, length/ width ratios of antennomeres as: III 10/9: IV 38/7: V 44/8: VI 39/7: VII 46/13: VIII 37/8: IX 48/12: X 44/12: XI 51/13. Pronotum and elytra not microsculptured. Pronotum weakly narrowed anteriad, with regularly rounded lateral margins, lateral margins carinae throughout visible in dorsal view; punctation on disc very fine, sparse, hardly visible at magnification 30×, consisting of sharply delimited punctures, puncture intervals much larger than puncture diameters, punctures along lateral carinae absent. Minute tip of scutellum exposed. Elytra fairly narrowed apically, lateral margins almost regularly curved, lateral margin carinae exposed throughout in dorsal view, shape of apices sexually dimorphic; sutural margin not raised, adsutural areas flat, narrow, each with single puncture row. Sutural striae converging apically, curved near pronotal lobe, not extended laterally along basal margins. Punctures along lateral margins absent. Elytral disc with punctures very fine and shallow, somewhat larger than those on pronotal disc, not clearly delimited, puncture intervals mostly about three to five times as large as puncture diameters. Hind wings completely reduced. Hypomera smooth. Mesepimera almost two times longer than interval to mesocoxae and about five times as long as wide. Metaventrite lacking microsculpture except on minute areas near metacoxae, entirely very finely and sparsely punctate, antecoxal puncture rows absent; margin of intercoxal process slightly concave; submesocoxal lines convex, very finely punctate; submesocoxal areas 0.04 mm, about as long as halves of shortest intervals between them and metacoxae. Metanepisterna flat, not narrowed anteriad, with straight suture. Abdominal ventrite I very finely and sparsely punctate, without obvious microsculpture; submetacoxal lines subparallel, distinctly punctate, 0.03 mm, about as long as seventh of shortest intervals between them and apical margin of ventrite. Following ventrites with conspicuous punctulate microsculpture.

Male characters. Protarsomeres I strongly widened, about as wide as apices of protibiae and almost twice as wide as tarsomeres III; protarsomeres II somewhat narrower than protarsomeres I ( Fig. 8 View Figs 1–19. 1–5 ). Protibiae straight, mesotibiae straight near base, curved posterior basal fourth ( Fig. 9 View Figs 1–19. 1–5 ), metatibiae slightly curved posterior basal third. Elytral apices truncate, perpendicular to sutural margin, inner apical angles in level with outer apical angles ( Fig. 50 View Figs 50–53 ). Median part of metaventrite with large, subtriangular impression. Abdominal ventrite VI with deeply emarginate apical margin ( Fig. 10 View Figs 1–19. 1–5 ). Tergite IX with one macroseta on each plate, stalk widened basally, with lateral sections concavely impressed ( Fig. 11 View Figs 1–19. 1–5 ). Aedeagus ( Figs 6, 7 View Figs 1–19. 1–5 ) 0.65 mm long, asymmetrical. Median lobe with small basal bulb bearing proximal anchor-like process, apical process asymmetrically curved, with small subapical tooth. Basal parts of parameres strongly expanded, apical parts lobate bearing very dense pores. Internal sac simple, tubular, membranous, lacking sclerotized pieces.

Female characters. Elytra with prominent apical angles, apical margins oblique and concave, inner apical angles situated far posterior outer apical angles ( Fig. 51 View Figs 50–53 ). Median part of metaventrite flattened. Pro- and mesotibiae straight, metatibiae hardly bent, tarsomeres not widened. Gonocoxite bent, evenly narrow ( Fig. 12 View Figs 1–19. 1–5 ).

Differential diagnosis. The sexually dimorphic elytra are unusual within the Scaphisomatini . They are described in several species of the Scaphisoma tricolor species group (see LÖBL & OGAWA 2016), which are quite unrelated to S. ancora sp. nov. Unlike in S. ancora sp. nov., the inner apical elytral angles are usually denticulate in females of the S. tricolor group. Members of the S. tricolor group differ notably by the elytra with shortened sutural striae, the strigulate abdominal microsculpture, the aedeagi with large, weakly sclerotized basal bulbs lacking proximal processes, the apical processes of the median lobes consisting of asymmetrical dorsal and ventral branches, the parameres lobed and overlapping apically, and the complex internal sacs. An anchor-like aedeagal process is well developed in the Moluccan S. semibreve Löbl, 2014. This species also shares reduced hind wings, likely correlated with a short metaventrite. Scaphisoma semibreve differs notably from S. ancora sp. nov. by the internal sac of the aedeagus bearing rows of robust teeth-like sclerites, and by the abdomen lacking microsculpture.

Etymology. The species epithet is a Latin noun in apposition, ancora, meaning ‘anchor’, and refers to the shape of the proximal aedeagal process.

Distribution. Indonesia, Central Sulawesi.


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