Lathrobium (Lathrobium) extraculum, Assing, 2010

Assing, Volker, 2010, On the Lathrobiina of Taiwan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 60 (2), pp. 301-361 : 312-314

Lathrobium (Lathrobium) extraculum sp. n. ( Figs 32-40 )

Type material:

Holotype ♂: " Taiwan, Pingtung Hsien, Peitawushan ridge, 2800-2910 m, 28.IV.1992, A. Smetana [ T105 ] / Holotypus ♂ Lathrobium extraculum sp. n., det. V. Assing 2010" (cSme) . Paratypes: 3 ♂ ♂, 4 ♀ ♀: same data as holotype (cSme, cAss) ; 2 ♀ ♀: " Taiwan, Pingtung Hsien, Peitawushan, above Kuai-Ku Hut , 2750 m, 29.IV.1992, A. Smetana [ T107 ]" (cSme) .

Description:

Body length 4.5-5.5 mm; habitus as in Fig. 32 . Externally highly similar to L. involutum , except for the pronounced microsculpture on the head ( Fig. 33 ). Reliably distinguished only based on the primary and secondary sexual characters:

♂: posterior margin of sternite VII weakly concave, pubescence not distinctly modified ( Fig. 34 ); sternite VIII 1.05-1.10 times as long as wide, posterior excision in slightly asymmetric position, small, its depth slightly more than 1/10 the length of sternite ( Fig. 35 ); aedeagus 0.90-0.95 mm long, with spear shaped ventral process and with internal structures of distinctive shape, long internal structure shaped like a corkscrew apically ( Figs 36-37 ).

♀: tergite VIII with posterior margin obtusely angled in the middle ( Fig. 38 ), latero-ventral parts extended, but much less so than in L. involutum , not meeting ventrally; sternite VIII distinctly oblong, approximately 1.30-1.35 times as long as broad, much longer than tergite VIII, and distinctly produced posteriorly ( Fig. 39 ); tergite X 1.8-1.9 times as long as tergite IX in the middle ( Fig. 40 ).

Comparative notes:

Based on the similar external and the secondary sexual characters, as well as particularly on the derived morphology of the aedeagus, L. extraculum belongs to the L. involutum group. From other species of this group, it is reliably distinguished only by the shape and internal structures of the aedeagus and by the shape of the female tergite VIII.

Etymology:

The specific epithet (Latin, noun in apposition: corkscrew) refers to the conspicuous shape of the long internal structure of the aedeagus.

Distribution and natural history:

The species was collected in two localities in the Peitawushan, Pingtung Hsien, southern Taiwan, where it is probably endemic. The type specimens were sifted from leaf litter, moss, and other

debris in a fir forest with bamboo, juniper, and rhododendron undergrowth and in a broadleaved forest at altitudes of 2750-2910 m.

Figures

Figs 32-40: Lathrobium extraculum sp. n.: habitus (32); forebody (33); male sternite VII (34); male sternite VIII (35); aedeagus in lateral view (36-37); female tergite VIII (38); female sternite VIII (39); female tergites IX-X (40). Scale bars: 32-33: 1.0 mm; 34-35, 38-40: 0.5 mm; 36-37: 0.2 mm.