Zyras (Zyras) gratellus CAMERON, 1939

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 : 155-156

Zyras (Zyras) gratellus CAMERON, 1939

( Figs 26, 39 , 72, 74 , 110 , 222–226 , 234–238 )

Zyras (Zyras) gratellus CAMERON, 1939b: 20 .

Type material examined: Lectotype ♂: “ F. C. Drescher, G. Tangkoeban Prahoe, 4000-5000 Voet, Preanger , Java, 19-31.I.1933 / Z. gratellus Cam Type / M. Cameron. Bequest. 1955-147. / Lectotypus ♂ Zyras gratellus Cameron , desig. V. Assing 2017” ( BMNH).

Comment: The original description is based on an unspecified number of syntypes from “G. Tangkoeban Prahoe” ( CAMERON 1944). The sole syntype found in the Cameron collection, a male, is designated as the lectotype.

Additional material examined: Malaysia: 1 ♂, Pahang, 1 km W ‘ Gap’ , 750–850 m, 8.II.1992, leg. Schillhammer ( NHMW); 1 ♂, Selangor, Ulu Gombak Field Studies Centre , 250 m, flight interception trap, 2–18. III.2004, leg. Maruyama et al. (cMar) . Indonesia: 1 ♂, Sulawesi Utara, Nani Wartabone [“Dumoga-Bone”] National Park , 200–300 m, lowland forest, Malaise trap, 9–16.V.1985 ( BMNH); 1 ♀, same data, but 200 m, 24.II.1985 (cAss) .

Redescription: Body length 4.8–5.3 mm; length of forebody 2.1–2.4 mm. Coloration ( Figs 26, 39 , 72, 74 , 110, 112 ): head and pronotum reddish to dark-brown; elytra dark-yellowish to reddish with the postero-lateral portions extensively, more or less distinctly, and diffusely darker, or elytra dark-brown with the anterior margin yellowish; abdomen uniformly pale-reddish to blackishbrown with the anterior portions of all tergites yellowish to reddish; antennae brown to dark-brown, antennomeres I–II sometimes slightly paler and antennomere XI reddish to dark-brown; maxillary palpi yellowish to darkbrown, with the terminal palpomere pale-yellowish.

Head ( Figs 72, 74 ) transverse, approximately 1.25 times as broad as long, broadly impunctate along middle; lateral dorsal portions with scattered fine punctures. Eyes large and bulging, more than twice as long as postocular region in dorsal view. Antenna ( Figs 26, 39 ) 1.55–1.70 mm long; antennomeres IV as long as broad or weakly transverse, V–X of gradually increasing width and increasingly transverse, X 1.5 times to nearly twice as broad as long, and XI conspicuously elongate, as long as, or longer than the combined length of VIII–X.

Pronotum ( Figs 72, 74 ) 1.14–1.15 times as broad as long and 1.10–1.20 times as broad as head, broadest near anterior angles, moderately tapering posteriad; lateral margins straight or convex in posterior two-thirds (dorsal view); punctation moderately fine to moderately coarse, sparse to moderately dense, and moderately irregularly distributed; laterally with more or less extensive impunctate patches; midline broadly impunctate; lateral margins each with four long brown setae; anterior margin with one long brown seta on either side.

Elytra ( Figs 72, 74 ) approximately 0.85–0.90 times as long as pronotum; punctation dense, moderately coarse, and more or less regularly distributed; interstices on average as broad as, or slightly broader than diameter of punctures; scutellum with coarse and defined punctation. Hind wings probably fully developed. Metatarsomere I as long as, or shorter than the combined length of II–IV.

Abdomen ( Figs 110, 112 ) distinctly narrower than elytra, with deep anterior impressions on tergites III–V; tergites III–V each with a transverse row of fine and weakly defined non-setiferous punctures in anterior impressions, with a lateral puncture on either side, and with a variable number of setiferous punctures at posterior margins; tergites IV–VI sometimes with a median pair of setiferous punctures; tergite VI with a transverse row of non-setiferous punctures anteriorly, with a lateral setiferous puncture on either side, and with approximately ten setiferous punctures at posterior margin; tergite VII with a transverse band of non-setiferous punctures anteriorly and with two transverse series of setiferous punctures posteriorly; tergite VIII ( Figs 225 , 237 ) with 15 long dark setae posteriorly, posterior margin smoothly convex, truncate, or weakly concave in the middle.

♂: posterior margin of sternite VIII ( Figs 226 , 238 ) obtusely angled in the middle; median lobe of aedeagus approximately 0.5 mm long and shaped as in Figs 222–223 , 234–235 ; paramere ( Figs 224 , 236 ) relatively small and slender, apical lobe small and with a conspicuously long terminal seta.

♀: posterior margin of sternite VIII weakly convex.

Intraspecific variation: The specimens from Sulawesi are distinguished from those from Peninsular Malaysia and Java by distinctly darker coloration of the forebody and the abdomen, a reddish antennomere XI (distinctly contrasting with the dark antennomeres I-X), and slight differences in the shape of the median lobe of the aedeagus. For comparison see Figs 26 , 72 , 110 , 222–226 versus Figs 39 , 74 , 112 , 234–238 . These differences are interpreted as intraspecific variation, also in view of the small number of specimens available.

Comparative notes: This species is readily distinguished from all other consubgeners particularly by the derived morphology and chaetotaxy of the paramere (small apical lobe with conspicuously long apical seta). It is additionally characterized by a conspicuously elongate antennomere XI and by the morphology of the aedeagus.

Distribution and natural history: This species is currently known from two localities in Peninsular Malaysia, one in Java, and one in Sulawesi Utara. The non-type specimens were collected with flight interception and Malaise traps. The altitudes range from 200 to more than 1200 m.

Figures

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 208–226: Zyras parvicollis (208–211), Z. ambulans (212–215), Z. nitens, holotype (216–221), and Z. gratellus (Malaysia) (222–226):medianlobeofaedeagusinlateralandinventralview(208–213,216–217,222–223);paramere (214,218,224); male tergite VIII (219, 225); male sternite VIII (220, 226); apical lobe of paramere (215); postero–median portion of male sternite VIII (221). Scale bars: 208–214, 216–220, 222–226: 0.5 mm; 215, 221: 0.1 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.