Stenus spiniferoides 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 : 349-350

Stenus spiniferoides Janák , sp. nov.

( Figs. 59–66 , 72 )

Type locality: South Africa, Western Cape, Bo-Langvlei Lake .

Type material. Holotype ♂: SOUTH AFRICA: Western Cape: “ South Africa, Western Cape, Wilderness section of Garden Route NP; 33°59.1´S, 22°40.4´E, Bo-Langvlei lake nr. Malachit bird hide, 6.ii.2012, J. Janák lgt. ( TMSA), “ HOLOTYPUS Stenus spiniferoides sp. nov., J. Janák det. 2021” ( TMSA) . Paratype ♀: same data as holotype ( JJRC) . Paratype with additional label “ PARATYPUS Stenus spiniferoides sp. nov., J. Janák det. 2021” .

Description (n = 2). Body length 3.6 mm (HT) and 3.9 mm (PT), fore parts 2.0 mm (HT) and 2.1 mm (PT). Macropterous, black, shiny, fore parts moderately coarsely and moderately densely punctate, abdomen moderately coarsely and moderately densely punctate; pubescence distinct, recumbent ( Fig. 59 ). Two first segments and basal parts of segments 3–5 of antennae reddish, remaining parts of segments more or less infuscate, club brown. Basal segments of maxillary palpi yellow, apical half of segment 3 slightly infuscate, apical three quarters of segment 4 brownish. Basal third of femora reddish, apical two thirds of femora and tibiae brown to dark brown, tarsi brown. Clypeus black, labrum dark brown, moderately densely pubescent.

Head moderately narrower than elytra (HT 68.1/85.8 = 0.79, PT 0.74), frons broad (average distance between eyes 33–36), 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; antennal tubercles, median part and posteriolateral parts largely impunctate, surface smooth, without any reticulation. Antennae moderately long, when reflexed extending approximately to posterior margin of pronotum, penultimate segments slightly longer than broad.

Pronotum strongly convex, distinctly longer than broad (HT 61.3/55.9 = 1.10), broadest near middle, distinctly constricted behind; with distinct anterior transverse impression and lateral impressions in posterior half, thus anterior margin seems to be elevated; punctation coarse and irregularly dense, diameter of average punctures as large as basal diameter of second antennal segment or slightly larger, punctation in median part in general less dense and with unpunctured elevations.

Elytra subquadrate, moderately broader than head, about as long as broad or slightly broader than long (R length/width HT = 85.3/85.8 = 0.99, PT 0.95), shoulders slightly oblique, sides slightly rounded and widened behind, distinctly constricted in posterior one-third, posterior margin moderately emarginated (sutural length 74– 76); sutural and humeral impressions distinct; two lateral impression present, first in middle and second in posterior quarter; punctation markedly coarser than on pronotum, moderately dense, diameter of punctures slightly larger than maximal diameter of second antennal segment, interstices mostly as large as diameter of punctures, in some areas less dense and with few small unpunctured areas.

Abdomen quite narrow, basal constriction of segments deep, tergite 7 with distinct membranous fringe apically; punctation on tergite 3 moderately coarse and dense, interstices about one half or up to twice larger than 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 apicomedially spinose ( Figs. 64–65 ). Legs moderately slender, metatarsi two thirds as long as metatibiae, segment 1 slightly shorter than segments 2 and 3 combined, markedly shorter than the last, segment 4 deeply bilobed. Fore parts and abdomen not reticulate, only tergite 8 with very faint traces of reticulation (visible at magnification of 70 x).

Male. Apical half of femora moderately enlarged. Sternite 6 apico-medially moderately densely and finely punctured and long setose, sternite 7 apico-medially flattened, very finely and sparsely punctured and long setose with posterior margin markedly emarginated, sternite 8 along middle slightly flattened, with deep, inwards narrowed subtriangular emargination in about posterior one-fifth ( Fig. 62 ). Sternite 9 deeply emarginated apico-medially, with long apicolateral teeth ( Fig. 63 ). Aedeagus 0.67 mm, narrowed apically, in apical fourth slightly emarginate ( Fig. 61 ), parameres exceed markedly the median lobe, widened apically, with numerous (about 31–33) setae.

Female. Sternite 8 broadly rounded apically. Valvifer acute posteriorly ( Fig. 66 ).

Differential diagnosis. S. spiniferoides Janák , sp. nov. is very similar to S. spinifer Fauvel, 1907 (the holotype was examined, Figs. 53–58 ), but differs by larger and more markedly unpunctured areas and more coarse and less dense punctation on pronotum and elytra, by more slender aedeagus with more apically enlarged parameres and by much more modified last sternites in male (male sternites 6 and 7 in S. spinifer are almost unmodified, shortly setose, posterior margin of sternite 7 only with almost indistinct very narrow and shallow emargination ( Fig. 54 ) and emargination of male sternite 8 is larger and less deep: see Fig. 56 ).

Derivatio nominis. The name refers to the similarity to Stenus spinifer .

Distribution. S. spiniferoides Janák , sp. nov. is currently known from Bo-Langvlei lake in Western Cape Province.

Bionomics. The type specimens were found by treading of dense reeds on a lake banks together with S. separatus ( Figs. 72 ).

Figures

FIGURES 53–66. 53–58: Stenus spinifer Puthz, holotype. 59–66: Stenus spiniferoides Janák, sp. nov., 59–64, holotype; 65–66, paratype. 53, 59, habitus; 54, 60, abdomen ventral; 56, male sternite 8, transmitted light; 62, male sternites 6–8, reflected light; 57, 63, male sternite 9; 58, 64, male tergite 10; 65, female tergite 10; 66, valves. Scale 1 mm: 53–54, 59–60; 0,5 mm: 55, 61; 0,5 mm: 56–58; 62–66.

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).