Scaphoxium bilobum, Lobl, 2015

Löbl, Ivan, 2015, On the Scaphidiinae (Coleoptera: Staphylinidae) of the Lesser Sunda Islands, Revue suisse de Zoologie 122 (1), pp. 75-120 : 117-119

Scaphoxium bilobum sp. nov.

Figs 118-120

Holotype: MHNG; ♂; Indonesia, Lombok, Mt. Rinjani , ca 400 m nr. Waterfalls, 5.XI.91 Löbl, veg. debris nr. river.

Paratypes: MHNG; 3 ♂; Indonesia, Lombok Mt. Rinjani above Senaro 900-1100 m 6.XI.1991, I. Löbl forest floor litter. – MHNG; 1 ♀; Lombok Batu Coq (N of G. Rinjani) 500 m, sec. forest in gorge D. Agosti, 12.03.1991.

Etymology: The species epithet is a Latin adjective referring to the lobed parameres.

Description: Length 1.38-1.45 mm, width 0.65- 0.67 mm, dorsoventral diameter 0.74-0.76 mm. Body fairly dark reddish-brown. Femora and tibiae slightly lighter, apex of abdomen, tarsi and antennae light, almost yellowish. Length/width ratio of antennomeres as follows: III 17/5: IV 16/4: V 25/5: VI 35/6: VII 35/9: VIII 28/10: IX 33/10: X 30/10: XI 38/10. Pronotal punctation very fine, hardly visible at 50x magnification. Scutellum concealed. Elytral punctation somewhat less fine than pronotal punctation; sutural striae starting about 0.15 to 0.25 mm behind margin of pronotal lobe. Mesoventrite with narrow median groove, not striate. Mesepisterna very finely punctate. Median part of metaventrite slightly convex, flattened near metacoxal process, very finely punctate. Lateral parts of metaventrite with several comparatively coarse punctures, impunctate near apical margin. Submesocoxal areas about 0.05 mm long, shorter than interval to metacoxae. Submesocoxal lines coarsely punctate. Metanepisternum flat, 0.05 mm wide, with straight suture. Abdomen with distinct punctate microsculpture, basal punctures on sternite 1 distinct, remaining abdominal punctation hardly visible.

Male: Protarsi hardly widened. Aedeagus (Figs 118-120) 0.41-0.44 mm long. Median lobe with acute tip. Parameres narrowed between bases and subapical lobe, latter rounded, with strongly narrowed apical section about as long as fourth of parameral length. Internal sac with pair of mesal rods and pair of admesal plates tapering proximally, membranes lacking denticulate or spine-like structures.

Distribution: Indonesia: Lombok.

Type locality: Lombok, Mt. Rinjani, ca 400 m nr. Waterfalls.

Comments: Following congeners possess lobed parameres and internal sac bearing two pairs of sclerites: S. oxyurum (Löbl, 1977) and S. cuspidatum (Löbl, 1977) from Australia, S. keralense Löbl, 1979 from India, S. taiwanum Löbl, 1980 from Taiwan, and S. avidum Löbl, 1990 and S. topali Löbl, 1981 from Vietnam. The latter species differs drastically by the parameres abruptly widened posterior subapical lobes. Scaphoxium cuspidatum , S. oxyurum , and S. avidum may be distinguished from S. bilobum by the internal sac having an additional small sclerite. The sclerotized pieces of the internal sac are very small and distant in S. keralense , and this species has also denticulate membranes in the middle part of the internal sac. Finally, S. bilobum may be easily distinguished from S. taiwanum by the narrower parameres and the proximally strongly narrowed admesal pair of sclerites of the internal sac.