Elytrobium alesianum, Assing, 2013

Assing, Volker, 2013, Two new genera of Lathrobiina from the East Palaearctic region (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 63 (2), pp. 219-239 : 230-232

Elytrobium alesianum sp. n.

( Figs 45-57 , Map 1 )

Type material:

Holotype : “ TAIWAN Chiai Hsien, Alishan, Sister Ponds 2180 m, 26.IV.1990, A. Smetana [ T24 ] / Holotypus  Elytrobium alesianum sp. n., det. V. Assing 2013” (cAss). Paratypes: 1 : “ TAIWAN Taoyuan Hsien, Taku- anshan For. 17.IV.90 1600 m, A. Smetana [ T3 ]” (cAss); 1 : “ TAIWAN, Taichung Hsien, Anmashan, 2225 m, 11-15. V.92, A. Smetana [ T122 ]” (cSme) .

Etymology:

It is with great pleasure that I dedicate this species to Aleš Smetana (Ottawa), one of the foremost staphylinidologists of all times, whose outstanding material from Taiwan has so significantly contributed to the knowledge of the staphylinid fauna of this island and who collected the majority of the type specimens studied in the present paper .

Description:

Small species; body length 5.0- 5.8 mm; length of forebody 2.0- 3.2 mm. Habitus as in Fig. 45 . Coloration: body black; legs with the femora blackish-brown, the tibiae dark-brown, and the tarsi yellowish-brown; antennae dark-yellowish, with antennomere I darker; maxillary palpi yellowish.

Head ( Fig. 46 ) 1.12-1.15 times as long as broad, broadest across eyes or at posterior margin of eyes, tapering behind eyes; lateral margins smoothly curving towards neck in dorsal view; posterior angles indistinct; frons transversely impressed and with pronounced microsculpture; punctation coarse and dense, sparser in median dorsal portion; interstices narrower than diameter of punctures (except in median dorsal portion), with very distinct microreticulation and subdued shine. Eyes mod- erately large and composed of numerous fine ommatidia, approximately half as long as postocular region from posterior margin of eye to neck in dorsal view. Antenna ( Fig. 47 ) 1.5-1.6 mm long; antennomeres IV-X approximately as long as broad. Maxillary palpi with palpomere III distinctly dilated apicad, barely 2.5 times as long as broad.

Pronotum ( Fig. 46 ) approximately 1.2 times as long as broad and 1.15-1.17 times as broad as head, moderately convex in cross-section, broadest slightly behind middle; lateral margins weakly convex in dorsal view, nearly straight; punctation similar to that of head; interstices with distinct microreticulation; impunctate median band very narrow and short, reaching neither anterior nor posterior margins.

Elytra ( Fig. 46 ) long, 1.07-1.09 times as long as pronotum; punctation dense, as coarse as that of pronotum, defined, irregular, not seriate; interstices without microreticulation, glossy. Hind wings fully developed. Protarsomeres

Key to the species of Elytrobium 1. Larger species, length of forebody at least 3.4 mm. Species from China and Japan. ................................................. 2

-

Smaller species, length of forebody 3.2 mm at most. Species from China and Taiwan. ............................................ 4 2. Maxillary palpomere III strongly dilated, little more than twice as long as broad. Male sternite VIII posteriorly very shallowly concave ( Fig. 4 ). Aedeagus as in Figs 5-6 . Japan. ........................................................ monilicorne (SHARP)

-

Maxillary palpomere III slender, approximately 3.5 times as long as broad. Male sternite VIII more distinctly excised posteriorly. Aedeagus of different shape. China. ............................................................................................................ 3 3. Pronotum without trace of microsculpture ( Fig. 15 ). Elytra, distinctly glossy; punctation defined and as coarse as that of pronotum ( Fig. 15 ). Antennomeres II-XI reddish. Male sternite VIII more distinctly oblong ( Fig. 17 ). Aedeagus approximately 0.9 mm long, larger than in other species of the genus, and shaped as in Figs 20-21 . Qinling Shan. ....................................................................................................................................................... qinlinganum sp. n.

-

Pronotum, except for the impunctate median band, with shallow microsculpture ( Fig. 8 ). Elytral punctation less defined and finer than that of pronotum; interstices less glossy ( Fig. 8 ). Antennomeres II-VI dark-brown. Male sternite VIII weakly oblong ( Fig. 4 ). Aedeagus smaller, 0.75 mm long and shaped as in Figs 12-13 . Gongga Shan. ................................................................................................................................................................... gongganum sp. n. 4. Pronotum without microsculpture ( Fig. 23 ). Male sternite VII weakly transverse ( Fig. 25 ). Posterior excision of male sternite VIII relatively deep ( Fig. 26 ). Aedeagus with ventral process apically acute, not hooked ( Figs 28-29 ). China: Jiangxi: Jinggang Shan. ............................................................................................................. seminitidum sp. n.

-

Pronotum with distinct microreticulation ( Figs 31 , 46 ). Male sternite VII more strongly transverse ( Figs 33 , 48 ). Posterior excision of male sternite VIII shallow ( Figs 34 , 49 ). Ventral process of aedeagus apically hooked ( Figs 36 , 51, 54 ). .................................................................................................................................................................................. 5 5. Head with lateral margins smoothly curving towards neck, not tapering immediately behind eyes. Elytra shorter, approximately as long as pronotum ( Fig. 31 ). Male sternite VII more strongly transverse, 1.45 times as broad as long ( Fig. 33 ). Male sternite VIII weakly oblong ( Fig. 34 ). Aedeagus slightly larger (0.65 mm) and shaped as in Figs 36-37 . Female sternite VIII less oblong, 1.1 times as long as broad ( Fig. 38 ). China: Daba Shan. ..................... ......................................................................................................................................................................... scindens sp. n.

-

Head tapering posteriad immediately behind eyes. Elytra longer, 1.07-1.09 times as long as pronotum ( Fig. 46 ). Male sternite VII less transverse, 1.35 times as broad as long ( Fig. 48 ). Male sternite VIII distinctly oblong ( Fig. 49 ). Aedeagus 0.57-0.61 mm long and shaped as in Figs 51-55 . Female sternite VIII more oblong, 1.3 times as long as broad ( Fig. 56 ). Taiwan. ............................................................................................................................ alesianum sp. n.

I-IV strongly dilated in both sexes. Metatarsomere I approximately as long as II.

Abdomen distinctly narrower than elytra, segments III-VI of subequal width; punctation moderately dense and moderately coarse on anterior tergites, gradually becoming finer and sparser towards the abdominal apex; interstices with shallow microreticulation; posterior margin of tergite VII with palisade fringe.

: sternite VII ( Fig. 48 ) moderately transverse, approximately 1.35 times as broad as long, and with very weakly concave posterior margin, pubescence unmodified; sternite VIII ( Fig. 49 ) distinctly oblong, posterior excision very shallow and not angled in the middle, pubescence unmodified; aedeagus 0.57-0.61 mm long, ventral process abruptly bent subapically and apically distinctly hooked in lateral view ( Figs 51-55 ).

: sternite VIII strongly oblong, approximately 1.3 times as long as broad and with distinctly convex posterior margin.

Comment:

The female from the Anmashan is only tentatively included in the type series. Its head is of slightly different shape (not tapering immediately behind eyes), the lateral margins of the pronotum are subparallel, the elytra are dark-brown, and the legs are paler than in the male specimens. These differences are interpreted as an expression of intraspecific variation until evidence suggesting otherwise becomes available. Nevertheless, except for the female sexual characters, the above description is exclusively based on the two males.

The aedeagus appears to be subject to some intraspecific variation, too. In the paratype from the Takuanshan, it is somewhat smaller and the ventral process is apically more slender than in the holotype ( Figs 51-55 ).

Comparative notes:

Both in external and in sexual characters, E. alesianum is most similar to E. scindens , from which it is distinguished by the different head shape, the longer elytra, the slightly shorter and more strongly dilated maxillary palpomere III, the less transverse male sternite VII, the more oblong male sternite VIII, the slightly smaller and differently shaped aedeagus, and the more strongly oblong female sternite VIII.

Distribution and natural history:

The species was discovered in three localities in Taiwan ( Map 1 ). The holotype was sifted from debris, leaf litter, and moss along a stream in an old, probably original mixed broadleaved and coniferous forest, the male paratype was collected in a mostly coniferous forest by dipping moss and vegetation along two small ponds into water, and the female paratype was found in a yellow pan trap in a primary mixed forest (SMETANA pers. comm.). The altitudes range from 1600 to 2225 m .

Figures

Map 1: Distribution of Elytrobium gen. n. in the southeastern East Palaearctic region: E. gongganum sp. n. (open circle); E. qinlinganum sp. n. (open triangle); E. scindens sp. n. (filled diamonds); E. seminitidum sp. n. (open diamond); E. alesianum sp. n. (filled circles); E. monilicorne (SHARP) (filled triangle).

Figs 45-57: Elytrobium alesianum sp.n. (45-53: holotype): habitus (45); forebody (46); antenna (47); male sternite VII (48); male sternite VIII (49); male sternite IX (50); aedeagus in lateral and in ventral view (51-52, 54-55); apical portion of ventral process of aedeagus in ventral view (53); female sternite VIII (56); postero-median portion of female sternite VIII (57). Scale bars: 45-46: 1.0 mm; 47-49, 56: 0.5 mm; 50-55, 57: 0.2 mm.

Figs 1-13: Elytrobium monilicorne (SHARP) (lectotype) (1-6) and E. gongganum sp. n. (7-13): habitus (1, 7); forebody (2, 8); male sternite VII (3, 9); male sternite VIII (4, 10); aedeagus in lateral and in ventral view (5-6, 12-13); male sternite IX (11). Scale bars: 1-2, 7-8: 1.0 mm; 3-4, 9-10: 0.5 mm; 5-6, 11-13: 0.2 mm.

Figs 14-29: Elytrobium qinlinganum sp. n. (14-21) and E. seminitidum sp. n. (22-29): habitus (14, 22); forebody (15, 23); antenna (16, 24); male sternite VII (17, 25); male sternite VIII (18, 26); male sternite IX (19, 27); aedeagus in lateral and in ventral view (20-21, 28-29). Scale bars: 14-15, 22-23: 1.0 mm; 16-18, 24-26: 0.5 mm; 19-21, 27-29: 0.2 mm.

Figs 30-44: Elytrobium scindens sp. n. (30-42) and Lathrobium elongatum (LINNAEUS) (43-44): habitus (30); forebody (31); median portion of ventral aspect of head (32); male sternite VII (33); male sternite VIII (34); male sternite IX (35); aedeagus in lateral and in ventral view (36-37); female sternite VIII (38); female tergites IX-X (39); right mandible (40); labrum (41, 43); labium (42, 44). Scale bars: 30-31: 1.0 mm; 33-34, 38-39: 0.5 mm; 32, 35-37, 40: 0.2 mm; 41-44: 0.1 mm.