Octavius sarkae, Janák, 2014

Janák, JiĜí, 2014, New species and subspecies of Octavius from South Africa, with a key and additional distribution records (Coleoptera: Staphylinidae: Euaesthetinae), Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 195-231 : 216-217

Octavius sarkae sp. nov.

( Figs 46–48, 51 , 60 )

Type locality. South Africa, Eastern Cape Province, Silaka NR, 31°38ƍS, 29°30ƍE.

Type material. HOLOTYPE: 3: ‘ SOUTH AFRICA, [Eastern Cape Province]: Transkei, Silaka Nature Reserve , 31.38 S – 29.30 E, forest floor litter, 30.xi.1988, E-Y: 2592, leg. Endrödy-Younga // Octavius sarkae sp. n., J. Janák det. 2009’ ( TMSA) . PARATYPES: 533 4♀♀: same data as holotype (7 spec. in TMSA, 2 spec. in JJRC), 2433 23♀♀: same data as holotype, but ‘Port St. Jones, Silaka, 31.33 S – 29.30 E, sifting, in indigenous forest, 23.xi.1988, E-Y: 2533’ (30 spec. in TMSA, 17 spec. in JJRC).

Description. Body length 1.6-2.0 mm (M 1.8 mm, HT 1.8 mm), forebody length 0.8–0.9 mm (M 0.8 mm, HT 0.8 mm). Macrophthalmous, apterous, light brownish to brownish, tergites 7 and 8 sometimes darker, head and pronotum dull, elytra and abdomen moderately shiny.

Head distinctly narrower than pronotum (R 0.85–0.88, M 0.87, HT 0.88), eyes moderately large, less than twice as long as eyes (R 1.18–1.62, M 1.47, HT 1.38), the latter straight, rounded posteriorly, median impression on frons absent, lateral parts of head moderately granulose, median part very densely and ¿nely reticulate.

Pronotum distinctly broader than long (R 1.10–1.17, M 1.14, HT 1.11), strongly narrowed posteriorly; anterior angles slightly angular, dorsal impressions shallow, transverse impression deep, lateral impressions deep and delimited by a sharp longitudinal ridge laterally; lateral parts beside lateral impressions densely granulose, remainder of surface ¿nely granulose, densely and deeply reticulate.

Elytra subquadrate, much broader than long (R 1.43–1.52, M 1.48, HT 1.46), with a sharp longitudinal ridge laterally; irregularly granulate and moderately reticulate except for narrow more shiny longitudinal areas along suture.

Male. Sternite 8 broadly emarginate in posterior eighth ( Fig. 46 ), sternite 9 as in Fig. 47 . Aedeagus strongly sclerotised, flattened dorso-ventrally, acute apically (n = 5, length 0.42–0.46 mm, M 0.44 mm, HT 0.43 mm). Internal structures of aedeagus with a long widened plate rounded apically. Median lobe with high sharp ventral ridge apically ( Figs 48, 51 ). Parameres asymmetrical, one of them slighly to distinctly longer than the other, each with 3–5 apical setae.

Differential diagnosis. Octavius sarkae sp. nov. belongs among species with large eyes, with the temples at most twice as long as eyes, with the head not or at most slightly widened posteriorly, with large body size and disc of head without a median impression. It is related to O. microps ( Kistner, 1967) and O. ruthae Janák, 2007 , from which it differs by the shape of the aedeagus, which is markedly flattened dorso-ventrally, with relatively wide and apically acute median lobe. Octavius sarkae sp. nov. can be distinguished externally (sometimes with dif¿culties) from O. ruthae Janák, 2007 occurring also in Ntsubane (type locality of O. sarkae ntsubane subsp. nov.) by deeper reticulation on the disc of pronotum, more shining sutural region of elytra and coarsely granulate elytra. The nominotypical subspecies of Octavius sarkae sp. nov. differs from O. sarkae ntsubane subsp. nov. and O. sarkae xhosa subsp. n. (both described below) only by the morphology of the aedeagus, which is characterised by the apical portion of internal sclerotised plate rounded, not ¿shtail- or hook-shaped, and by the median lobe with a high and sharp ventral ridge apically.

Etymology. This species is dedicated to my daughter Šárka.

Bionomics. All specimens have been found in siftings of forest litter in indigenous forest.

Distribution. The nominotypical subspecies of Octavius sarkae sp. nov. is currently recorded only from Silaka NR in Eastern Cape Province, South Africa ( Fig. 60 ).

Note. The species is hitherto known from a series of specimens from three forests separated by the distance of ca. 30 km and situated in the coastal region of Eastern Cape known as Wildcoast ( Fig. 60 ). The region is characterized by parallel flowing rivers which separate parts of indigenous forests by deep valleys. These specimens are hardly distinguishable externally and have the same general form of aedeagus and its internal structures, but each series has in detail speci¿c (and within the series little variable) form of the aedeagus and its internal structures. According to my opinion the best way how to treat the observed differences and distribution is to consider O. sarkae as a polytypic species with probably geographically isolated subspecies, which are described below.

Figures

Figs 42–47. 42–45 – Octavius multisetosus sp. nov., male. 42, 44, 45 – HT; 43 – PT. 46, 47 – O. sarkae sp. nov., HT male. 42 – aedeagus ventral; 43 – apical part of aedeagus ventral; 44, 46 – sternite 8; 45, 49 – sternite 9. Scale bars = 0.1 mm.

Figs. 48–53. 48, 51 – Octavius sarkae sp. nov. 49, 52 – O. sarkae xhosa subsp. nov. 50, 53 – O. sarkae ntsubane ssp. nov. 48-50 – aedeagus ventral, HT; 51-53 – aedeagus ventro-lateral, PT. Scale bars = 0.1 mm.

Fig. 60. Distribution of Octavius sarkae sp. nov., O. sarkae ntsubane subsp. nov. and O. sarkae xhosa subsp. nov.