Syndicus (Semisyndicus)

Zhou, De-Yao & Yin, Zi-Wei, 2017, New data on the genus Syndicus Motschulsky (Coleoptera: Staphylinidae: Scydmaeninae) from Yunnan, southern China, Zootaxa 4247 (5), pp. 569-576 : 570-575

Syndicus (Semisyndicus) long Zhou and Yin, new species

( Figs 1 B, 4A–G, 5A)

Type material (1 ♂). Holotype: CHINA: ♂, labeled ‘ China: Yunnan, Lincang City (临沧市), Yun County (云县), Manwan Town (漫湾镇), Shuibatou Village (水坝头村) 24°40'12''N, 100°20'31''E, under bark of rotten wood, 2100m, 13.iii.2016, Zi-Chun Xiong leg.’.

Diagnosis. The remarkable C-shaped endophallic structure seen in the lateral view of the aedeagus is unique for this species and not known in any other Semisyndicus species.

Description. Body ( Fig. 1 B) slender, moderately convex, uniformly dark brown, legs and palpi slightly lighter. BL 3.21 mm.

Head wider than long, widest at relatively small eyes, HL 0.54 mm, HW: 0.64 mm. Tempora longer than length of eye, rounded; vertex relatively long, convex, with very small, hardly noticeable median tubercle adjacent to posterior margin; frons concave; supraantennal tubercles well marked, distinctly demarcated from frons but indistinctly from vertex. Punctation of frons and vertex composed of sharply marked punctures distributed densely and slightly unevenly; setation relatively short, composed of thin, suberect setae. Antennae ( Fig. 4 G) relatively short, AnL 1.43 mm, relative lengths of antennomeres: 1.7: 1.5: 1.8: 1.7: 1.5: 1.4: 1.5: 1.5: 1.5: 1.5: 1.6.

Pronotum ( Fig. 5A ) relatively slender and elongate, widest near anterior 1/4–1/3, PL 0.90 mm, PWm 0.75 mm, PWb 0.64 mm. Anterior and lateral margins rounded together; lateral constriction very distinct, located in posterior third; lateral groove missing; posterior collar relatively long; demarcated from disc by transverse row of four large and deep dorsal pits; additional pit near each hind angle very small; area between inner pair of basal pits raised and forming indistinctly delimited median longitudinal carina; base of pronotum regularly rounded. Punctation on discal part much more distinct than that on head, composed of much larger, unevenly distributed and dense punctures of various diameters, largest punctures are located in central part of disc, posterior collar behind basal pits bearing sparser and smaller punctures. Setation distinctly denser than that on head, relatively short, suberect.

Elytra long, oval, widest anterior to middle, EL. 1.76 mm, EW 1.17 mm, EI 1.50. Humeri well-marked, delimited from adsutural area by broad and shallow impression; very narrow adsutural area near base distinctly raised; median circumsutural area on elytra slightly impressed near anterior third. Punctation distinct, composed of smaller punctures than those on pronotum, punctures are moderately dense and evenly distributed, largest on median impression and reducing in diameters and depth toward lateral and posterior margins; setation slightly lighter in color than that on pronotum, moderately dense, setae relatively short, slightly suberect.

Aedeagus ( Fig. 4 A–C) 0.74 mm in length, elongate; parameres ( Fig. 4 F) slender with apices slightly exceeding emarginate apex of median lobe, each paramere with several short preapical setae ( Fig. 4 F). Endophallus ( Fig. 4 D– E) asymmetrical, with darkly sclerotized central complex located near base of median lobe, and a sub-pentagonal apical plate located near apex of median lobe. A strongly curved sclerite extends from the base of central complex, it is curved to form C-shaped open loop, with apex directed ventrally.

Female. Unknown.

Comments. External characters and body proportions of S. long are similar to those of S. sinensis and S. sichuanicus . The new species differs from S. sinensis in its larger body size (3.21 mm vs. 2.93 mm in S. sinensis ), more coarsely punctate pronotum, and longer antennomere III in comparison to antennomere II. Syndicus long is hardly distinguishable from S. sichuanicus by external morphology, only slightly longer body (3.21 mm vs. 3.05 mm in S. sichuanicus ) and slightly more slender pronotum may serve to preliminarily distinguish these two species. However, the unique presence of a unique C-shaped, strongly sclerotized endophallic structure can be used to unambiguously separate S. long from all similar congeners.

Bionomics. The single male was collected under bark of a decaying log in a mixed forest at Lincang.

Distribution. Southern China: Yunnan ( Fig. 6 ).

Etymology. This species is named after a Chinese character ‘Long (龙)’, which represents a mythical creature from the traditional Chinese mythology.

Figures

FIGURE 1. Dorsal habitus of Syndicus species. A. Syndicus himalayanus from Yunnan, male. B. S. long, holotype male.

FIGURE 4. Male diagnostic features of Syndicus long. A. Aedeagus, in ventral view. B. Same, in lateral view. C. Same, in dorsal view. D. Endophallus, in ventral view. E. Same, schematic. F. Apical portion of paramere, enlarged. G. Right antenna.

FIGURE 5. A. Head and pronotum of Syndicus long. B – C. Habitat of S. himalayanus in Yunnan: Nabang Town, photography by Fang-Ling Qiu.

FIGURE 6. Distribution of Syndicus in China.