Paederus bilobus, Li, Xiao-Yan, Solodovnikov, Alexey & Zhou, Hong-Zhang, 2014

Li, Xiao-Yan, Solodovnikov, Alexey & Zhou, Hong-Zhang, 2014, Three new species of the genus Paederus Fabricius (Coleoptera: Staphylinidae: Paederinae) from China, Zootaxa 3765 (4), pp. 382-388 : 383-384

1. Paederus bilobus sp. nov.

Figures 1 A–G.

Type material. Holotype, ♂, China: Hainan, Ledong County, Jiangfeng (18.70N, 108.69E) 81 m, 2009. XII.1, leg. Meiying Lin ( IZCAS); Paratypes, ♀, same data as holotype; 1♀, Baishan County, Mt. Yingge (river bank, light trap), 2009. V.5, leg. Tingyu Hu; 1♀, Mt. Wuzhi, Shuiman 600 m, 2007. V.8, leg. Zongyi Zhao; 1♀, ♂, Lingshui, Diaoluo Shan 180 (18.67N, 109.91E) 180 m, 2007. III.27, leg. Hongliang Shi and Feng Yuan; 5♀, 7♂, Mt. Yingge 418 m (brook, light trap), 2009. VI.5, leg. Liang Li ( IZCAS, ZMUC).

Description. Entire body length: 6.2 mm mean values are given, 18 specimens; forebody length 2.9 mm, width: 1.1 mm. Body brownish yellow except black elytra and two apical segments of abdomen, and brown antennomeres 3–10.

Head with HL/HW =0.8. Eyes median sized, distinctly protruding laterally, HL/EL = 0.28, diameter of eye longer than gena and as long as temple (ratio, gena: eye: temple = 0.75: 1: 1).

Surface of head smooth without clear microsculpture. Vertex and middle of frons glabrous. Punctation on lateral portions of head irregularly distributed, with punctures of variable size, sparse, shallow and coarse, denser around eyes and temporal areas. Most punctures with black or blackish brown oblique setae of variable length.

Labrum without distinct teeth or protrusions on anterior margin, anterolateral angle protruded anteriad. Median tooth of mandible bicuspid, apically rounded. Antennae with pubescence starting from antennomere VI. Gular sutures broadly separated with basal 2/ parallel. Nuchal ridge long, ending in ventral side and forming an obtuse angle anteriad at middle and broadly sinuate, basal ventral ridge of neck short. Neck with longitudinal and thick ridge ventrally. Pronotum with PL/PW = 1.06. Scutellum longer than wide and nearly parallel-sided, with dull surface, reticulate microsculpture and sparse pubescence. Mesoventrite broad with coarse and dense punctation.

Elytra parallel-sided, ELL\EW = 1.12, ESL/ELL = 0.85. Surface with luster and reticulate microsculpture, punctures on surface larger, denser and deeper than on head or pronotum, arranged irregularly, diameter of a puncture slightly shorter than interspaces between punctures, each puncture with an oblique brown seta.

Abdomen widest at segment VI (4th visible). Setiferous punctures on tergites fine and sparse, denser laterally, base of each tergite rugose, without punctures. Tergite VII with slightly pale and narrow posterior margin. Tergite VIII with sharply acute apex. Sternites with punctation denser and larger than on tergites, base of each sternite with relatively sparse punctures.

Male. Sternites III–VI without modifications, sternite VII with triangular glabrous area in the middle. Median excision of sternite VIII with clear ridge. Sternite IX with distinct symmetrical inner ridge, apex of sternite IX truncate.

Aedeagus ( Figs. 1 B–D, G) 0.98 mm, length/width = 2.5, apex acute and straight, not reaching apices of parameres. Parameres symmetrical with lateral margins sinuate and apices slightly curved ventrally. Dorsal plate broad basally and gradually narrowed posteriad, with acute apex, basal part with pair of strongly sclerotized and horn-like lobes. Internal sac ( Figs. 1 B, D) with one largely and strongly sclerotized thorn with curved and acute apex.

Female. Sternite VIII ( Fig. 1 E) with shallow apico-lateral emarginations, and widely rounded apex. Sternite IX ( Fig. 1 F) moderately wide and gradually narrowed posteriad with basal and apical margins slightly emarginated, longitudinal depression shallow with faint lateral borders.

Comparison. In habitus, Paederus bilobus sp. nov. is a very peculiar species within the genus Paederus and can be very easily distinguished from the congeners by the following characters: its head is brownish yellow, and middle segments of antennae (antennomeres 4–10) are black, the anterior margin of labrum without teeth, while the dorsal plate of the aedeagus has a pair of strongly sclerotized and horn-like lobes on its basal part. Externally, the new species resembles the Paederus subgenera Heteropaederus Scheerpeltz , and Oreinopaederus Scheerpeltz based on the parallel-sided elytra and well-developed hind wings. But it can be distinguished from both subgenera by the symmetrical and straight parameres ( Figs. 1 B–D, 1G), while the parameres in both West Palearctic species of Heteropaederus are asymmetrical, and apices of parameres in P. (Oreinopaederus) vastus Scheerpeltz, 1976 from Nepal, the single species in the subgenus, are curved ventrally (fig. 4 in Scheerpeltz, 1976).

Etymology. The species name is derived from the Latin words bi- (two), and lobus (lobe). It refers to the structure of the dorsal plate of the median lobe in the aedeagus.

Distribution. The distribution of Paederus bilobus sp. nov. is confined to few localities in Hainan Province. This species was collected in grassland at river banks at the foot of the mountains of Yingge and Wuzhi, at low altitudes between 80 m and 600 m. According to the available data, this species was collected in the period from May to December by light-traps.

Figures

FIGURES 1. Paederus bilobus sp. nov. from Hainan. A. habitus; B. aedeagus, ventral view; E. aedeagus, lateral view 1; D. aedeagus, dorsal view; E. sternite VIII, female; F. sternite IX, female; G. aedeagus, lateral view 2. Scale bars: A = 1 mm; B – E, G = 0.5 mm; F = 0.25 mm.