Octavius barbetonensis Janák, 2025

Janák, Jiří, 2025, Overview of Octavius of Mpumalanga and Limpopo Provinces, South Africa (Coleoptera: Staphylinidae: Euaesthetinae) with descriptions of eight new species, Zootaxa 5737 (1), pp. 105-126 : 108

Octavius barbetonensis Janák sp. nov.

Figs. 6–10 , 84 , 95

Type locality. South Africa, Mpumalanga, Songimvelo Nature Reserve , 25°56.7', S 31°6.4'E .

Type material ( 57 specimens). Holotype ♂: “ RSA, Mpumalanga 18.xi.2023 / 25°56.7'S 31°6.4'E, / Songimvelo NR, ind. forest / 1340m, J. Janák lgt.”, “Berlese extraction / leaf & log litter / sifting”, “ HOLOTYPUS Octavius barbetonensis sp. nov. J. Janák det. 2025” ( TMSA) ; Paratypes: 17 ♂, 28 ♀: same data as the holotype ( JJRC, PPRI, 1 ♂ stored in 96% alcohol) ; 3 ♂, 8 ♀: “ RSA, Mpumalanga 16.xi.2023 / 25°56.6'S 31°6.3'E, ind. for. / Songimvelo NR borders / 1470m, J. Janák lgt.”, “Berlese extraction / leaf & log litter / sifting” ( JJRC) . All paratypes with additional labels: “ PARATYPUS Octavius barbetonensis sp. nov. J. Janák det. 2025” .

Description. Body length 1.4–1.8 mm (M 1.5 mm, HT 1.4 mm), forebody length 0.7–0.8 mm (M 0.7 mm, HT 0.7 mm). Microphthalmous, apterous, light rusty, head and pronotum dull, elytra and abdomen moderately shiny ( Fig. 6 ).

Head ( Fig. 6 ) slightly narrower than pronotum (R 0.91–0.94, M 0.92, HT 0.93), eyes very small, temples about five times as long as eyes (R 4.40–5.18, M 4.82, HT 5.12), sides of head very slightly rounded, slightly widened behind eyes to maximal width, then moderately narrowed towards posterior angles, posterior angles moderately angular, elongate median impression on disc deep, sometimes shortened anteriorly and posteriorly, lateral parts of head finely granulose, median part densely and moderately finely reticulate.

Pronotum ( Fig. 6 ) slightly broader than long (R 1.07–1.13, M 1.10, HT 1.09), strongly narrowed posteriorly; anterior angles rounded, dorsal impressions deep, transverse impression shallow or deep, lateral impressions deep, not delimited by sharp longitudinal ridge laterally; lateral parts beside lateral impressions moderately densely granulose, remainder of surface moderately densely and finely reticulate.

Elytra ( Fig. 6 ) subquadrate, much broader than long (R 1.34–1.49, M 1.40, HT 1.49), with two sharp longitudinal ridges laterally; between latter and suture with two longitudinal impressions, irregularly granulate, moderately reticulate and sparsely shortly setose.

Abdomen subparallel, slightly widened to segment V or VI, with one paratergite and microsculpture consisting of triangular or rhomboid field, finely setose.

Male. Sternite VIII shallowly emarginate in posterior tenth ( Fig. 9 ), sternite IX as in Fig. 10 . Aedeagus strongly asymmetrical, moderately long ( 0.40–0.41 mm, M 0.41 mm, HT 0.40 mm) and wide, with narrow hook-shaped projection, with two strongly sclerotised internal structures, first one long, narrowed and rounded apically and second one shorter with small point apicolaterally; parameres slightly shorter than median lobe, with two setae in apical two third and 4–5 subapicolateral setae ( Figs. 7–8 ).

Differential diagnosis. Octavius barbetonensis Janák , sp. nov. belongs among species with very small eyes, with temples at about five times as long as eyes, with the head not or at most slightly widened posteriorly, with small body and the disc of the head with a median impression. In the most recent key of South African Octavius ( Janák 2014) is to be arranged at the couplet 94 (95) near O. trihastatus Puthz, 2006 and O. mostovskii Janák, 2014 , but it differs from the first species by dull, less transverse pronotum with shallower transverse impression, from the second species by presence of median impression of head and from both by different shape of aedeagus.

Derivatio nominis. This species refers to the type locality situated near the town Barbeton.

Distribution. Octavius barbetonensis Janák , sp. nov. is currently recorded only from the Songimvelo Nature Reserve and its surroundings, Mpumalanga Province, South Africa ( Fig. 95 ).

Bionomics. All specimens were collected in siftings of forest litter in an indigenous forest at the elevation of about 1300–1500 m a.s.l. ( Fig. 84 ) with the abundance of specimens per kg of sifted material: 1340 m a.s.l.: 4.1/kg, 1470 m a.s.l.: 2.6/kg).

Figures

FIGURE 95. Distribution of Octavius in Mpumalanga and Limpopo Provinces, South Africa.

FIGURES 1–10. 1–5. Octavius attenuatus Puthz, Mariepskop. 6–10. Octavius barbetonensis Janák, sp. nov., 6–7, 9–10, holotype; 8, paratype. 1, 6, habitus; 2–3, 7–8, aedeagus ventral; 4, 9, male sternite VIII; 5, 10, male sternite IX. Identical scales 0.1 mm: 2=3; 4=5; 7=8; 9=10.

FIGURES 83–88. 83: Forest near Josefsdal, type locality of O. hastifer; 84: National Reserve Songimvelo, type locality of O. barbetonensis; 85–87: Mount Mariepskop, mountain fynbos, locality of O. attenuatus, O. mariepskopensis, O. transvaalensis and O. trihastatus; 88: Mount Mariepskop, forest, locality of O. attenuatus, O. transvaalensis and O. trihastatus.