Zyras (Zyras) densissimus, Assing, 2017

Assing, Volker, 2017, On Zyras sensu strictu in the East Palaearctic and Oriental regions, with a focus on the faunas of the Himalaya, India, Sri Lanka, Thailand, and Sulawesi (Coleoptera: Staphylinidae: Aleocharinae: Lomechusini), Beiträge Zur Entomologie = Contributions to Entomology 67 (1), pp. 117-192 : 160-161

Zyras (Zyras) densissimus spec. nov.

urn:lsid:zoobank.org:act:C82B20D3-1259-446E-B077-0D026B057901

( Figs 36 , 75 , 111 , 239–244 , Map 10 )

Type material: Holotype ♂: “ INDONESIA: SULAWESI UTARA, Dumoga-Bone N.P. , 24 Februar 1985. / Plot A, ca 200 m, Lowland forest / Flight interception trap 2 / R .Ent.Soc. Lond. , Project Wallace, B.M. 1985-10 / 29.21 / Holotypus ♂ Zyras densissimus sp. n., det. V. Assing 2016” ( BMNH) . Paratypes: 1 ♂: same data as holotype (cAss) 1 ♂: same data as holotype, but “ May 1985.” ( BMNH) ; 1 ♀: same data as holotype, but “ April 1985. / Malaise trap / ‘ Edwards Camp’, Lowland forest , 664 m, 26.IV–28.V ” ( BMNH) .

Etymology: The specific epithet (adjective) is the superlative of the Latin adjective densus (dense). It alludes to the conspicuously dense and fine punctation of the forebody.

Description: Small species; body length 4.0– 4.7 mm; length of forebody 1.9–2.1 mm. Coloration ( Figs 36 , 75 , 111 ): forebody blackish-brown with the anterior and humeral portions, sometimes also the suture, of the elytra more or less extensively reddish-yellow; abdomen dark-brown to blackish-brown with parts or all of tergites II–V and parts of the paratergites reddish to dark-reddish; antennae dark-yellowish with antennomeres IV–VIII more or less distinctly and more or less extensively brown to blackish-brown; maxillary palpi dark-yellowish to pale-brown with the terminal palpomere pale-yellowish.

Head ( Fig. 75 ) distinctly transverse; punctation very dense and rather fine; along middle without punctation. Eyes large and bulging, more than twice as long as postocular region in dorsal view. Antenna ( Fig. 36 ) very slender, approximately 2.0 mm long; antennomeres IV–V approximately twice as long as broad, V–X of gradually decreasing length and decreasingly oblong, IX weakly oblong, X weakly oblong or as long as broad, and XI as long as the combined length of IX and X.

Pronotum ( Fig. 75 ) weakly transverse, 1.05–1.08 times as broad as long and approximately 1.1 times as broad as head, broadest near anterior angles, moderately tapering posteriad; lateral margins straight in posterior two-thirds (dorsal view); punctation fine, regular, and conspicuously dense, also along midline; lateral margins without long setae.

Elytra ( Fig. 75 ) approximately 0.85 times as long as pronotum; punctation similar to that of pronotum; scutellum with very coarse and defined punctation. Hind wings fully developed. Metatarsomere I approximately as long as the combined length of II–IV.

Abdomen ( Fig. 111 ) narrower than elytra, with deep anterior impressions on tergites III–V; tergites III–V each with a transverse row of 6–8 defined, large and deep non-setiferous punctures in anterior impressions, with a lateral setiferous puncture on either side, but without setiferous punctures at posterior margin; tergite VI with few fine non-setiferous punctures anteriorly, with a lateral setiferous puncture on either side, without setiferous punctures at posterior margin; tergite VII with scattered fine non-setiferous punctures anteriorly and with two transverse rows of four setiferous punctures posteriorly, each composed of only four punctures, posterior margin with palisade fringe; tergite VIII ( Fig. 243 ) with eight long setae at posterior margin, a few setae postero-laterally, and with fine pubescence in posterior half, posterior margin convex, without median concavity.

♂: sternite VIII ( Fig. 244 ) with fine and rather dense pubescence in posterior half, posterior margin weakly to distinctly convex; median lobe of aedeagus ( Figs 239–241 ) 0.57–0.58 mm long, slender, and of very distinctive morphology; ventral process long and slender, with sinuate lateral margins in ventral view; paramere ( Fig. 242 ) approximately as long as median lobe and with long and slender apical lobe.

♀: posterior margin of sternite VIII weakly concave in the middle.

Comparative notes: This highly distinctive species is readily identified and distinguished from its consubgeners by the characteristic punctation of the forebody, the punctation pattern of the abdomen (particularly the absence of setiferous punctures at the posterior margins of tergites III–VI, the large and deep punctures in the anterior impressions of tergites III–V, and the scattered fine non-setiferous punctures in the anterior portions of tergites VI and VII), and by the conspicuous shape of the aedeagus. In addition, it is characterized by small body size, long and slender antennae, the coloration of the antennae, and by the absence of long setae at the pronotal margins.

As can be inferred from the similarly derived punctation of the forebody and the abdomen, as well as from the similarly slender antennae and habitus, Z. densissimus is closely allied to Z. bryanti CAMERON, 1943 (female holotype examined; male unknown) from Borneo, from which it differs by different coloration ( Z. bryanti : pronotum pale-reddish; abdominal segments III-V and VIII reddish-yellow), even denser and finer punctation of the forebody, and a more convex (cross-section) and posteriorly more strongly tapering pronotum (cross-section).

Distribution and natural history: The known distribution is confined to Nani Wartabone National Park in Sulawesi Utara, North Sulawesi ( Map 10 ). The type specimens were collected with flight interception and Malaise traps in lowland forest at altitudes of 200– 660 m.

Figures

Map 10: Revised distributions of Zyras preangeranus (black circles), Z. brevilobatus (white star), Z. parvicollis (white star), Z. ambulans (white circle), Z. densissimus (black star), Z. titan (black star), Z. densihirtus (black star), and Z. nigrihirtus (black star) in the southern East Palaearctic and Oriental regions.

Figs 1–41:Antennae of Zyrasspp.:kraatzi(1),exasperatus(2),pindarae (3–5),perforatus(6),championi(7),pallipes (8),condignus (9), nitens (10), truncatus (11), nilgiriensis (12), hirsutiventris (13), russiceps (14), brignolii (15), hastatus (16), parageminus (17–18), latilobatus (19), alternans (20), hirtus (21), nigroaeneus (22), luteipes (23), longilobatus (24), morvani (25), gratellus (Malaysia) (26), castaneus, lectotype (27),proximus (28–29),novinversus (30–31), brevilobatus(32), parvicollis(33), ambulans (34),matangensis (35), densissimus (36), densihirtus (37), nigrihirtus (38), gratellus (Sulawesi) (39), gardneri (40), titan (41). Scale bar: 1.0 mm.

Figs 68–81: Forebody (68–77), head and pronotum (78), and abdomen (79–81) of Zyras spp.: brevilobatus (68), parvicollis (69), ambulans (70), nitens, holotype (71), gratellus (Malaysia) (72), matangensis (73), gratellus (Sulawesi) (74), densissimus (75), titan (76), densihirtus (77), nigrihirtus (78), kraatzi (79), asperatus (80), nigroaeneus (81). Scale bar: 1.0 mm.

Figs 100–116: Abdomen of Zyras spp.: luteipes (100), nilgiriensis (101), brevilobatus(102), brignolii (103), parvicollis (104), proximus, holotype (105), novinversus (106), ambulans (107), matangensis (108), nitens (109), gratellus (Malaysia) (110), densissimus (111), gratellus (Sulawesi) (112), titan (113), russiceps (114), densihirtus (115), nigrihirtus (116). Scale bar: 1.0 mm.

Figs 227–244: Zyras parahirtus (227–228, 231–232), Z. matangensis (229–230, 233), Z. gratellus (Sulawesi) (234–238), and Z. densissimus (239–244): median lobe of aedeagus in lateral and in ventral view (227–230, 234–235, 239–241); paramere (231, 236, 242); male tergite VIII (232, 237, 243); male sternite VIII (233, 238, 244). Scale bars: 227–233, 237–238, 243–244: 0.5 mm; 234–236, 239–242: 0.2 mm.