Octavius gracilis Janák, sp. nov.

(Figs. 78–84, 121, 131)

Type locality. South Africa, KwaZulu-Natal Province, Maloti-Drakensberg Park, Lotheni National Reserve .

Type material (18 specimens). Holotype ♂: “ South Africa, KwaZulu-Natal, Maloti-Drakensberg Park, Lotheni NR, ind. forest patch 29°26.3ʼS 29°31.7ʼE, 1570m, 14.i.2019, J. Janák lgt.”, “Berlese extraction, leaf & log litter, sifting”, “HOLOTYPUS Octavius gracilis sp. nov. J. Janák det. 2021” (TMSA). Paratypes: 10 ♂, 7 ♀: same data as holotype (TMSA, JJRC, 1 ♀ in 96 % alcohol). All paratypes with additional labels: “ PARATYPUS Octavius gracilis sp. nov. J. Janák det. 2021”.

Description. Body length 1.1–1.3 mm (M 1.17 mm, HT 1.2 mm), forebody length 0.4–0.5 mm (M 0.48 mm, HT 0.5 mm). Microphalmous, apterous, rusty, slightly shiny (Fig. 78).

Head (Figs. 79–80) slightly broader than pronotum (R 1.05–1.10, M 1.07, HT 1.08), eyes represented only by one ommatidium (Figs. 79–80, o), sides of head widened moderately towards posterior angles, posterior angles moderately angular, median impression on disc absent, surface with very fine reticulation consisting of irregular polygonal fields and very fine punctures raising from center of each field.

Pronotum (Figs. 79–80) markedly longer than broad (R 1.14–1.27, M 1.20, HT 1.27), strongly narrowed posteriorly; anterior angles rounded, disc regularly convex, disc and base without impressions, posterior angles shortly rounded; surface finely irregularly reticulate and very finely punctate, similarly as on head.

Elytra (Figs. 79–80) roundly trapezoid, markedly broader than long (R 1.18–1.31, M 1.23, HT 1.18, slightly broader than head (R 1.08–1.15, M 1.12, HT 1.12), with sharp outer longitudinal ridge laterally; surface with very fine reticulation consisting of irregular polygonal fields and then and there with very fine punctures.

Abdomen with two paratergites, with reticulation consisting of polygonal, slightly transverse fields, very finely and sparsely punctate.

Male. Posterior margin of sternite VIII broadly rounded (Fig. 83), sternite IX as in Fig.84.Aedeagus symmetrical, long and narrow (length 0.23–0.24 mm, M 0.24 mm, HT 0.23 mm), apical part pointed, basal part with internal tube, internal sac with two “V” shaped internal structures, pair of very short sclerotized narrow structures and pair of longer curved structures in apical part; with 1 apical and 2 subapical moderately long fine setae, all oriented laterally (Figs. 81–82).

Differential diagnosis. Octavius gracilis Janák, sp. nov. belongs among species with one ommatidium together with O. angusticollis Puthz, 2006 and additional four species described in this paper and can be distinguished with certainty only by the shape of the aedeagus and the internal structures – see a key at the end of the description part for details.

Derivatio nominis. The name refers to the slender shape of the aedeagus.

Distribution. Octavius gracilis Janák, sp. nov. is currently recorded only from the Lotheni Natural Reserve in Drakensberg Mts., KwaZulu-Natal Province, South Africa (Fig. 121).

Bionomics. All specimens were collected in siftings of litter in a patch of an indigenous forest at the elevation of about 1570 m a.s.l. with the abundance 1.4 specimens per kg of sifted material (Fig. 131).