Scopaeus kokodanus Cameron, 1938

Frisch, Johannes & Mainda, Tobias, 2022, The Scopaeus kokodanus species group (Coleoptera: Staphylinidae: Paederinae) from New Guinea and the Solomon Islands, with description of three new species, Soil Organisms 94 (3), pp. 139-147 : 140

The Scopaeus kokodanus Cameron, 1938 species group

Diagnosis: Medium sized to large, macrophthalmous, alate Scopaeus with slender body and appendages ( Figs 1–4 ). Body length 3.6–5.0 mm, forebody length 2.1 – 2.8 mm. Head slightly elongate to strongly pyriform with maximum width across eyes and tempora evenly narrowed from eyes to neck constriction, head 1.08 – 1.16 times as long as wide, head across eyes 1.17 – 1.42 times as wide as tempora at half of length from eyes to neck constriction. Median labral denticles acute, lateral labral denticles shorter and stouter, with about right-angled apex. Antenna slender with elongate distal segments, penultimate segment 1.1 – 1.14 times as long as wide. Protarsomeres about twice as wide as long. Legs slender, tibia of mesothoracic leg 6.7 – 11.2 times as long as wide. Elytra with well developed shoulders, about 1.1 – 1.23 times as long as pronotum. Metathoracic wings fully developed and functional. Surface of forebody shiny with very fine and spacious setose punctation and without microreticulation. Abdomen finely microreticulate, matter than forebody.

Male: Aedeagus with long phallobase and comparatively short distal lobes ( Figs 5–7 ); in dorsal and ventral view ( Figs 9, 10, 12, 13, 15, 16 ), lateral lobes strongly projecting, each bearing apical and ventral group of long setae; apical lobes short, almost semicircular at apex in dorsal and ventral view ( Figs 9, 10, 12, 13, 15, 16 ), with somewhat emarginate ventrodistal margin ( Figs 8, 11, 14 ); dorsal lobe evenly narrowed towards apex in lateral view ( Figs 8, 11, 14 ), with subtriangular ( Fig. 10 ) to round ( Figs 13, 16 ) apex in dorsal view; flagellum short and without modifications ( Figs 8, 11, 14 ). Abdominal sternite VII ( Figs 17, 19, 21 ) slightly and broadly emarginate posteriorly and with strong, asetose, median depression covering more than median half of sternite width and all of sternite length, except for strongly sclerotized posterior margin, and being surrounded by a varying number of long, black, medioposteriad pointing setae. Posterior margin of abdominal sternite VIII ( Figs 18, 20, 22 ) with two deep, lateral emarginations forming narrow median lobe with more or less shallow distal emargination.

Female: Sperm pump ( Figs 23 , 34) of characteristic shape of Scopaeus s. str. ( Frisch et al. 2002: 30, 35, 44, Figs 24 –29), but without species group and species specific features. Bursa copulatrix (see Frisch et al. 2002: 30, Fig. 27) hyaline, without sclerotizations.

Distribution: As far as known presently, the Scopaeus kokodanus species group is confined to the Australasian region and hitherto known from New Guinea and the Solomon Islands.

Bionomics: According to the sparse label information, members of the Scopaeus kokodanus species group were collected on banks of rain forest streams and rivers, which matches the major habitat preference of Scopaeus as described by Frisch et al. (2002: 28), at elevations between 200 and 750 m a.s.l.. The locality of S. balkei in the Foja Mountains ( Fig. 25 ) is representative for this habitat type of Scopaeus in tropical rain forests. Specimens of S. balkei were flushed by the alluvial method from semishaded gravel banks of this stream and similar localities in the Cyclops Mountains.

Comparative notes: The Scopaeus kokodanus species group is well defined according to the apomorphic characters of the primary and secondary sexual characters described above. The slender body shape of S. kokodanus and S. arfakmontium with the characteristic pyriform head is, however, widespread in the genus, found in various species groups and thus a convergency. An example is the Australian S. ctenocryptus Lea, 1923 ( Frisch 2016: Fig. 4 ), which strongly resembles the habitus of these species, but has sexual characters notably different from those of the S. kokodanus species group ( Frisch 2016: Figs 20–22 , 60).

Figures

Figure 25. Habitat of Scopaeus balkei in the Foja Mountains, Indonesia, Papua Province.

Figures 1–4. Habitus of Scopaeus kokodanus, Papua New Guinea, Morobe, Waritaian (1), S. arfakmontium, paratype, Indonesia, West Papua,Arfak Mts (2), S. balkei, paratype, Indonesia, Papua, Cyclops Mts (3), S. potamides, paratype, Solomon Islands, Kolombangara (4).

Figures 5–7. Aedeagus (in lateral view) of Scopaeus arfakmontium, holotype, Indonesia, West Papua, Arfak Mts (5), S. balkei, holotype, Indonesia, Papua, Cyclops Mts (6), S. potamides, holotype, Solomon Islands, Kolombangara (7). Abbreviations: dl – distal lobes, pb – phallobase.

Figures 8–16. Apical portion of aedeagus in lateral (8, 11, 14), ventral (9, 12, 15), dorsal view (10, 13, 16) of Scopaeus arfakmontium, holotype, Indonesia, West Papua, Arfak Mts (8–10), S. balkei, holotype, Indonesia, Papua, Cyclops Mts (11–13), S. potamides, holotype, Solomon Islands, Kolombangara (14–16). Abbreviations: al – apical lobes, dl – dorsal lobe, f – flagellum, ll – lateral lobe.

Figures 17–24. Abdominal sternite VII (17, 19, 21) and abdominal sternite VIII (18, 20, 22) of Scopaeus arfakmontium, holotype, Indonesia, West Papua,Arfak Mts (17, 18), S. balkei, holotype, Indonesia, Papua, Cyclops Mts (19, 20), S. potamides, paratype, Solomon Islands, Kolombangara (21, 22), S. kokodanus (23). Figs 23, 24: sperm pumps of (23) S. kokodanus, Papua New Guinea, Morobe, (24) S. balkei, paratype, Indonesia, Papua, Cyclops Mts.