Stenus volkerputhzianus Janák, 2022

Janák, Jiří, 2022, Four new species and additional records of the genus Stenus of southern Africa (Coleoptera: Staphylinidae: Steninae), Zootaxa 5174 (4), pp. 331-356 : 344-346

Stenus volkerputhzianus Janák , sp. nov.

( Figs. 38–46 , 69–70 )

Type locality. South Africa, KwaZulu-Natal Province, N borders of Himeville National Reserve .

Type material. Holotype ♂: SOUTH AFRICA: KwaZulu-Natal: “ South Africa , KwaZulu-Natal, 1560m; 29°44.7´S, 29°31.3´E, swamp: N borders of Himeville NR, 13.i.2019; J. Janák lgt.”, “ HOLOTYPUS Stenus volkerputhzianus sp. nov., J. Janák det. 2021” ( TMSA) . Paratypes: KwaZulu-Natal: 8 ♂, 8 ♀: same data as holotype (2 ♂, 2 ♀ in TMSA, 6 ♂, 6 ♀ in JJRC) ; 1 ♀: “ South Africa, KwaZulu-Natal Tugela river banks nr. Rugged Glen NR; 28°40.05´S 29°1.15´E 24.xi.2021; J. Janák lgt.”, “river banks, reeds, treading” ( JJRC) ; 1 ♀: “ South Africa, KwaZulu-Natal, Stoneybrook farm env. nr. Kokstad ; dam; 30°31.0´S, 29°19.9´E, 19.xi.2021, J. Janák lgt.”, “dam banks, reeds, treading” ( JJRC) ; Free State: 1 ♀: “ South Africa, Free State, Golden Gate NP, pond, 28°30.15´S, 28°35.35´E, 31.xii.2014; J. Janák lgt.” ( JJRC) ; Gauteng: 4 ♀: “ South Africa, Gauteng, Rietvlei NR; dam banks, 25°52.5´S 28°16.4´E; 30.xi.+ 2.xii.2021; J. Janák lgt.”, “dam banks, reeds, treading” (1 ♀ in TMSA, 3 ♀ in JJRC) ; 1 ♂: “ South Africa, Gauteng, E of Pretoria; Diamond Hill env.; 25°49.1´S 28°31.3´E, 28.xi.2021 ”, “treading, wetland”, J. Janák lgt. ( JJRC) . All with additional label “ PARATYPUS Stenus volkerputhzianus sp. nov., J. Janák det. 2021” .

Description (n = 10). Body length 4.3–5.3 mm (M 4.9 mm, HT 5.1 mm), fore parts 2.5–2.9 mm (M 2.7 mm, HT 2.7 mm). Macropterous, black, shiny, fore parts moderately coarsely and moderately densely punctate, abdomen moderately coarsely and moderately densely punctate; pubescence short, recumbent ( Fig. 38 ). Two first segments and basal part of third segment of antennae yellowish, following segments more or less infuscate, club dark brown. Basal segments of maxillary palpi yellow, apical half of segment 3 and segment 4 brownish. Basal half of femora reddish-yellow, apical half of femora, tibiae and tarsi brown to dark brown. Clypeus black, labrum dark brown, moderately densely pubescent.

Head moderately narrower than elytra (R 0.92–0.98, M 0.96, HT 97.3/113.2 = 0.86), frons broad (average distance between eyes 45–48), with two distinct longitudinal furrows, median part as broad as each of lateral parts, moderately elevated, not extending to level of inner eye margins; punctation moderately coarse and dense, diameters of punctures as large as basal diameter of second antennal segment or slightly large, but not reached maximal diameter of this segment; antennal tubercles and median part impunctate, surface smooth, without any reticulation. Antennae moderately long, when reflexed extending approximately to posterior margin of pronotum, penultimate segments one-half longer than broad.

Pronotum strongly convex, markedly longer than broad (R 1.10–1.17, M 1.12, HT 83.3/76.0 =1.10), broadest near middle, distinctly constricted behind; anterior transverse impression deep, thus anterior margin seems to be transversally elevated; punctation coarse and dense, diameter of average punctures slightly smaller than maximal diameter of second antennal segment.

Elytra subquadrate, moderately broader than head, about as long as broad or slightly broader than long (R length/width 0.93–1.01, M 0.97, HT 108.3/113.2 = 0.96), shoulders slightly oblique, sides slightly rounded and widened behind, distinctly constricted in posterior one-third, posterior margin moderately emarginated (sutural length 83–92); sutural and humeral impressions distinct, additional median impression in anterior half present, thus area between this and sutural impression seems to be elevated, lateral impression in posterior half present; punctation slightly coarser than on pronotum, moderately dense, diameter of punctures slightly larger than maximal diameter of second antennal segment, interstices mostly slightly smaller than diameter of punctures.

Abdomen broad, basal constriction of segments deep, tergite 7 with distinct membranous fringe apically; punctation on tergite 3 moderately coarse and sparse, punctures larger that those on head, but smaller than those on pronotum, interstices except for middle about as large as diameter of punctures, on following tergites gradually finer but not sparser; punctures on tergite 5 as large as one medial eye facet, punctures on tergite 7 markedly finer. Tergite 10 broadly and shallowly emarginated ( Figs. 44, 46 ). Legs moderately slender, metatarsi two thirds as long as metatibiae, segment 1 slightly shorter than segments 2 and 3 combined, about as long than last, segment 4 deeply bilobed. Pronotum except for medio-anterior part and elytra very finely and shallowly reticulate or only with traces of reticulation (visible at magnification of 70 x), abdomen densely and shallowly reticulate, remainder of surface smooth, without any reticulation.

Male.Apical fourth of femora moderately enlarged. Sternite 5 medially moderately densely and finely punctured, sternite 6 and 7 medio-posteriorly flattened, very finely and sparsely punctured and long setose, sternite 8 moderately broad, inwards narrowed subtriangular emargination in about posterior half ( Fig. 39 ). Sternite 9 with two distinct emarginations ( Fig. 43 ). Aedeagus 0.94–1.05 mm long (n = 5, M 1.01 mm, HT 1.02 mm), gradually narrowed apically, in middle and before apex slightly emarginate ( Figs. 40–42 ), parameres exceeds markedly median lobe, widened apically, with numerous (about 20–22) setae.

Female. Sternite 8 broadly rounded apically, without any projection. Valvifer acute posteriorly ( Fig. 45 ).

Differential diagnosis. This new species belongs to the bifrons group (species with bilobed tarsomere 4, abdomen without paratergites, tergite 10 apically rounded or slightly emarginated, sternite 9 and valvifer acute apically, legs markedly bicolored, aedeagus without inner flagellum). It can be distinguished from the species of the group with similar general shape of aedeagus (median lobe gradually narrowed apically): S. assimulatus Puthz, 1971 , S. diabolus Puthz, 1967 , S. kwaiensis Schubert, 1906 and Stenus pulchellulus Puthz, 1994 as follows: from S. kwaiensis Schubert, 1906 by markedly bicolored legs, apical part of median lobe of the aedeagus laterally concave, absence of setose area in posterior part of tergite 9, narrower apicolateral tooth of valvifera, from S. assimulatus Puthz, 1971 by much markedly apically narrowed median lobe; from S. diabolus Puthz, 1967 by narrower median lobe and markedly widened apical part of parameres and male sternite 8 with two emarginations and from Stenus pulchellulus Puthz, 1994 by not acute (but narrowly rounded) apical point of the median lobe.

Derivatio nominis. The species is dedicated to Volker Puthz, nestor of Stenus taxonomy as thanks of his support of my work on this genus.

Distribution. S. volkerputhzianus Janák , sp. nov. is currently known from KwaZulu-Natal, Free State and Gauteng provinces, South Africa.

Bionomics. The type specimens were found by treading in swamp, wetland, river or dam banks ( Figs. 69, 70 ).

Figures

FIGURES 38–46. Stenus volkerputhzianus Janák, sp. nov.: 38–40, holotype, 41–46, paratypes from Himeville. 38, habitus; 39, abdomen ventral; 40, aedeagus ventral, diffused light; 41, 42, aedeagus in reflected light (41, ventral; 42, dorsal); 43, male sternite 9; 44, male tergite 10; 45, valves; 46, female tergite 10. Scale 1 mm: 38–39; scale 0.5 mm: 40–46.

FIGURES 67–72. Localities where Stenus species were collected. S. hippoamicus Janák, sp. nov. (67, St. Lucia; 68, Ndumo); S. volkerputhzianus Janák, sp. nov. (69, Himeville, 70, Tugella river); S. hessei L. Benick, S. capicola L. Benick, S. depressiusculus L. Benick, S. cf. grandipennis L. Benick, 1933 (71, Olifantsbos); S. spiniferoides Janák, sp. nov. (72, Langvlei).