Stenus perpauper Puthz 2012, nov.sp.
Creators: name: Puthz, V.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Stenus
Stenus perpauper

description: Stenus perpauper nov.sp. (Figs 28, 53)
Type material: Holotype () and 8, 6 - paratypes: TAIWAN: Nantou Hsien: Shanlinchi, 1650m, 16.V.1990, A. Smetana (T 60); Kaohsiung Hsien: 1, 5: Tengchih (1400m), 21.-23.VII.2000, H. Sugaya; 1: ibidem, 21.VII.2000, idem; 1, 1: ibidem, 2.XI. 200, M. Maruyama; 1: ibidem, 20.IV.2001, H. Sugaya; 1: ibidem, 20.-30.IV.2004, idem. Chiayi Hsien: 1, 3: Fenchifu, 12.-13.XI.2000, H. Sugaya. - 1 (cf. det.): Nantou Hsien: Meifeng, 2130m, 3.V.1991, A. Smetana (T 62) (cS).- HT and PTT in coll. Smetana (Ottawa), PTT also in cN and in cP.
Description: Apterous, black with a brownish hue, slightly shiny, forebody coarsely and very densely punctate, abdomen moderately finely to finely, densely punctate. Antennae, maxillary palpi and legs reddish yellow.
Length: 2.6-2.9mm (forebody: 1.4-1.5mm).
PM of the HT: HW: 29; DE: 14; PW: 21.5; PL: 22.5; EW: 26.3; EL: 22.5; SL: 16.
Male: Metasternum shallowly impressed, coarsely and very densely punctate. Anterior sternites simple, sternite 7 finely and very densely punctate and pubescent along middle. Sternite 8 with a broad and shallow apical emargination (LS: ED= 48:4). Sternite 9 with long teeth apicolaterally. Aedeagus (fig. 28), apical portion of the median lobe broadly rounded, sometimes with the medial portion slightly prominent; parameres with 7-8 setae apically.
Female: Sternite 8 obliquely triangular at posterior margin. Valvifer with a long apicolateral tooth. Spermatheca (fig. 53).
Head broader than elytra, frons moderately broad with two broad longitudinal furrows, median portion about as broad as each of the lateral portions, distinctly but not much elevated, not exceeding the level of medial eye margins; punctation moderately coarse and very dense, diameter of punctures about as large as median cross section of antennal segment 3, interstices smaller than half diameter of punctures, can become slightly larger on actual middle of median portion. Antennae slender, when reflexed nearly extending to toward the posterior margin of the pronotum, penultimate segments nearly 1.5x as long as broad. Pronotum about as broad as long, sides convex, distinctly concave in posterior half; a very shallow oblique impression posterolaterally and a distinct longitudinal impression along middle; punctation coarse and very dense, slightly confluent near anterior and near posterior margin, diameter of punctures nearly as large as apical cross section of antennal segment 2, interstices distinctly smaller than half diameter of punctures, larger in the longitudinal impression, sometimes as large as two punctures combined. Elytra trapeziform, distinctly broader than long, impressions shallow (not conspicuous), punctation even coarser than on pronotum, punctures fully as large as apical cross section of antennal segment 2. Abdomen cylindrical, completely thread-like margined (no paratergites!), no apical membranous fringe at tergite 7; punctation moderately fine and variably dense anteriorly: punctures on tergite 4 less coarse than basal cross section of antennal segment 3, interstices as large or larger than punctures, punctures on tergite 7 very fine, finer than one eye-facet near medial eye margin, interstices mostly distinctly larger than punctures, tergite 10 very finely and sparsely punctate. Legs moderately slender, metatarsi nearly two thirds as long as metatibae, segment 1 much longer than the following two segments combined, somewhat longer than segment 4+5 combined; segment 4 deeply bilobed. The whole insect with dense microsculpture.
Comparative notes: This new species belongs to the large group of S. cephalotes SHARP and within this to a number of species with a thread-like abdominal margination. From the other apterous/micropterous Taiwanese species with the same abdominal character it is distinguished by the genitalia. From some of them furthermore by the relatively even elytra, which are dark and not distinctly brownish, and by the small size: Most similar to the new species S. parpauperculus nov.sp., from which it is distinguished by the sexual characters.
The punctation of the abdomen varies in single specimens, interstices can become larger or slightly smaller than diameter of punctures. This, together with minor differences in the shape of the apical portion of the median lobe, first led me to the assumption that the specimens of different populations might belong to different species. But since the shape of the spermatheca in all these populations do not show any convincing differences, I regard all the above quoted populations as belonging to the same slightly variable species.
Etymology: Since it is a small inconspicuous species I name it " perpauper " (Lat. = very miserable).
description: Published as part of Puthz, V., 2012, On the Stenus LATREILLE 1797 from Taiwan with non-spotted elytra (Coleoptera, Staphylinidae) (327 Contribution to the Knowledge of Steninae), pp. 1431-1475 in Linzer biologische Beiträge 44 (2) on pages 1436-1438, DOI: 10.5281/zenodo.5337424