Tetrasticta laotica, Assing, 2016

Assing, Volker, 2016, A new species of Tetrasticta from Laos (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 48 (1), pp. 229-234 : 230-233

Tetrasticta laotica nov.sp. ( Figs 1-4 , Map 1 )

Type material: Holotype ♂: " Lao, Phongsaly prov., 21°41-2'N 102°06-8'E, 28.v.- 20.vi.2003, Phongsaly env., ~ 1500 m, Vít Kubáň leg. / Holotypus ♂ Tetrasticta laotica sp. n., det. V. Assing 2015" ( NHMB) . Paratypes: 2♀♀: same data as holotype ( NHMB, cAss) ; 1♀: " Laos-N (Oudomxai), 1-9.v.2002, ~ 1100 m, 20°45'N 102°09'E, Oudom Xai (17 km NEE ), Vít Kubáň leg." ( NHMB) .

Etymology: The specific epithet is an adjective derived from Laos.

Description: Body length 4.2-5.0 mm; length of forebody 1.9-2.2 mm. Coloration: forebody blackish; abdomen pale-reddish; legs dark-yellowish to palebrown; antennae blackish-brown to black with the basal 2-3 antennomeres yellowish-red to reddish-brown; maxillary palpi yellowish.

Head ( Fig. 1 ) without sexual dimorphism, 1.20-1.25 times as broad as long; punctation moderately dense and rather fine; interstices without distinct microsculpture. Eyes very large and bulging, approximately four times as long as distance from posterior margin of eye to posterior margin of head in dorsal view. Antenna ( Fig. 2 ) 1.5-1.6 mm long; antennomere IV strongly transverse, asymmetrically disc-shaped, and approximately three times as broad as long; antennomere V much longer than IV; antennomeres V-X of subequal width and approximately 1.5 times as broad as long; XI barely as long as the combined length of IX and X.

Pronotum ( Fig. 1 ) strongly transverse, approximately 1.5 times as broad as long and 1.20-1.24 times as broad as head; lateral and posterior margins forming a semi-circle, posterior angles obsolete; disc with four coarse punctures forming a square in the middle, with a coarse lateral puncture on either side, and with additional finer punctation similar to that of head; interstices without microsculpture; lateral margins with five long and erect setae.

Elytra ( Fig. 1 ) 0.7-0.8 times as long as pronotum, distinctly gaping posteriorly; punctation fine and dense; interstices without distinct microsculpture. Hind wings present. Metatarsomere I slightly longer than the combined length of II and III.

Abdomen slightly narrower than elytra; tergites III-IV with, tergite V without shallow and narrow anterior impressions; punctation moderately fine and moderately dense; interstices without microsculpture; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII convex.

♂: median lobe of aedeagus ( Fig. 3 ) 0.63 mm long; ventral process weakly sinuate and apically acute; internal sac with long flagellum forming approximately seven coils basally.

♀: spermatheca ( Fig. 4 ) 0.2 mm long, with oval distal portion and with short and straight proximal portion.

Comparative notes: The new species differs from other geographically close Tetrasticta species by the shape of the median lobe of the aedeagus and additionally as follows:

from the similarly coloured T. thailandensis PACE, 2000 ( Thailand; male unknown) by the distinct punctation of the head and pronotum (indistinct or absent in T. thailandensis ), as well as the shape of the spermatheca (proximal portion of the capsule distinctly dilated apically);

from T. brevipennis (BERNHAUER, 1903) (widespread in the Oriental and East Palaearctic regions) by the absence of distinct dimorphisms of the head and segment VIII, the absence of microsculpture on the head and pronotum, the presence of four coarse macropunctures in the middle of the pronotum, the completely reddish abdomen ( T. brevipennis : at least segments V-VIII blackish), and numerous other characters;

from T. laeta MARUYAMA & SUGAYA, 2002 ( Japan, Taiwan) by uniformly black elytra and a reddish abdomen ( T. laeta : elytra yellow with black postero-lateral portions; abdomen blackish-brown);

from T. bicolor (CAMERON, 1943) ( Malaysia) by uniformly blackish elytra ( T. bicolor : elytra mainly yellow) and the reddish abdomen ( T. bicolor : abdomen blackish-brown); from T. bryanti (CAMERON, 1943) by the uniformly reddish abdomen ( T. bryanti : abdominal segments IV-VIII blackish-brown);

from T. elegans CAMERON, 1939 (Java) by much darker coloration of the forebody alone ( T. elegans : head and pronotum yellowish-red);

from T. javana CAMERON, 1939 (Java) by the uniformly black pronotum and elytra, and by the pale-reddish abdomen ( T. javana : pronotum red; humeral angles of elytra yellowish-red; abdominal segments V-VIII blackish);

from T. kinabaluensis PACE, 2008 (Borneo) by much stouter antennae, a completely reddish abdomen ( T. kinabaluensis : segments IV-VII brown), and a pronotum of different shape);

from T. caputcyrneum PACE, 2013 ( Malaysia) by the reddish abdomen and the absence of microsculpture on the whole body;

from T. gnatha YAMAMOTO & MARUYAMA, 2013 ( Malaysia) by the blackish antennomere IV (reddish in T. gnatha ) and the uniformly reddish abdomen (tergites V-VII infuscate in T. gnatha );

from T. bobbii ZHENG & ZHAO, 2014 ( China: Yunnan) by larger and more bulging eyes, a blackish antennomere IV (reddish in T. bobbii ), the uniformly blackish pronotum and elytra, a uniformly reddish abdomen (tergites V-VII at least partly infuscate in T. bobbii ), the presence of six coarse macropunctures on the pronotum (absent in T. bobbii ), and the shape of the spermatheca.

For illustrations of T. brevipennis , T. bicolor , T. bryanti , T. laeta , T. thailandensis , T. kinabaluensis , T. caputcyrneum , T. gnatha , and T. bobbii see MARUYAMA (2004), MARUYAMA & SUGAYA (2002), PACE (2000, 2008, 2013b), YAMAMOTO & MARUYAMA (2013), and ZHENG & ZHAO (2014).

Distribution and natural history: This species is currently known from two localities in Phongsaly and Oudom Xai provinces, North Laos ( Map 1 ). The type specimens were collected at altitudes of approximately 1100 and 1500 m.

Figures

Map 1: Distribution of Tetrasticta laotica nov.sp.

Figs 1-4: Tetrasticta laotica nov.sp.: forebody (1); antenna (2); median lobe of aedeagus (3); spermatheca (4). Scale bars: 1-2: 0.5 mm; 3: 0.2 mm; 4: 0.1 mm.