Flanged Bombardier beetles from Shanghai, China, with description of a new species in the genus Eustra Schmidt-Goebel (Coleoptera, Carabidae, Paussinae)

Abstract Four paussine species belonging to three different genera are discovered in Shanghai. A new species, Eustra shanghaiensis Song, sp. n., is described, illustrated, and distinguished from the treated congeners. New distributional data or biological notes on Eustra chinensis Bänninger, 1949, Itamus castaneus Schmidt-Goebel, 1846, and Platyrhopalus davidis Fairmaire, 1886 are provided.


Introduction
The ground beetle subfamily Paussinae Latreille, 1807 currently contains more than 30 species from China (Nagel 2003;Wrase and Schmidt 2007;Guéorguiev 2014;Maruyama 2014Maruyama , 2016Song et al. 2017;Wang 2017), among which only one is known to occur in Shanghai: Eustra chinensis Bänninger, 1949. During several recent collecting trips conducted in Shanghai, the senior author and his colleagues collected a large series of paussine specimens. The examination of the specimens revealed a new species of ozaenine genus Eustra and three known species.
According to the latest revision of Eustra (Deuve, 2001), the genus contains two species from China: E. chinensis (Shanghai, Taiwan; Type locality: Shanghai, China), E. taiwanica Deuve, 2001 (Taiwan;Type locality: Taiwan, China). In 2014, Guéorguiev described the first Chinese troglobitic Eustra species, E. petrovi from Xianrendong, Yunnan. In this paper, a new Eustra species is described from Shanghai, illustrations provideded of all Shanghainese paussines, and biological information about the habitats and behaviors of Eustra shanghaiensis sp. n., Eustra chinensis, Platyrhopalus davidis, and Itamus castaneus observed in nature and captivity are provided.

Materials and methods
Material used in this study is deposited in the following public and private collections:  (Figs 1A, 3A). The new species can be readily separated from latter by the pronotal front angles strongly produced, the wider aedeagus, the apex of aedeagal median lobe much shorter and wider and the relatively long apical portion of right paramere. It differs from its Shanghainese congener E. chinensis by the smaller body size and the different shape of aedeagus.

SNUC
Description. Body (Fig. 1A) 3.06-3.17 mm; yellowish-brown, head and pronotum somewhat reddish; each elytron with a dark spot. Head ( Fig. 2A) convex, gently covered with yellow setae, microsculpture faint; fully carinate near eyes; clypeus anteriorly gently concave, with 2 pairs of long setae at anterior margin; labrum with anterior margin minutely denticulate, with 12-14 long setae; Eyes somewhat small; antennae ( Fig. 2B) submoniliform, with antennomeres I and II clavate, increasing in diameter distally gradually; antennomere I somewhat shorter than 2nd and 3rd combined; antennomeres V-X almost as wide as long; antennomere XI evidently longer than the 1st. Pronotum (Fig. 2C) sparsely covered with yellow setae; distinctly wider than long, widest at apical third; moderately contracted anteriorly and posteriorly; disc moderately convex medially and reflexed on lateral sides; front angles strongly produced; midline distinct, almost reaching both anterior and posterior borders.
Pterothorax shaped as in Fig. 2E, meso-coxae disjunct, meta-coxae separated in midline of body. Elytra (Fig. 2F) densely punctulate and pubescent, distinctly wider than prothorax; shoulders rounded and not bordered; each side with an obscurely dark spot; surface moderately covered with short setae, but along the right side of dark spot glabrous. Hind wings well developed. Legs (Fig. 1A) relatively long and slender; both spurs of pro-tibiae (Fig. 2D) are terminal, almost equal in length.
Male. Sternite VII (Fig. 3E) wide, widely truncate, slightly acute at middle, with 4 long setae near apex. Median lobe of aedeagus shaped as in Fig. 3A, ends in a blunt tip, with a spoon-shaped sclerite on endophallus; right paramere ( Fig. 3B) arcuate, apical portion narrow and elongate; left paramere shaped as in Fig. 3C, large, almost glabrous, rounded at apex. Female. Gonopod IX shaped as in Fig. 3D. Comments. Moore et al. 2011 described and illustrated the larval structure of Eustra chinensis based on larval specimens collected together with some adults from Tianshan Park, Shanghai with no association ants (Fig. 6A). However, all these specimens are now reconsidered as larvae of the new species, Eustra shanghaiensis sp. n. described here.
Measurements  30°19'28"N, 119°26'54"E , alt. 380 m, 16.vii-9.viii.2017, Xiao-Bin Song leg., [F. I. T.].' Comments. Eustra chinensis is characterized by the large body size and the broad elytra. This is the only known myrmecophilous species of the genus Eustra. Adults are collected from Ectomomyrmes javana (Mayr, 1867) nests under the stone (Fig. 6B), and have been observed feeding on dead insects inside nest of E. javana (Maruyama et al., 2013). Wendy et al. (2011)    Comments. Zhao and Tian (2003) first recorded the ozaenine genus Itamus Loew, 1849 in China, with two known Asian species, i.e., I. castaneus from Guangdong and I. dentatus Andrews, 1919 from Guangxi. Itamus castaneus can be readily separated from its Chinese congener I. dentatus by the larger body size, shoulders of elytra almost without denticle and the fore-femur with an obvious projection. All specimens from Shanghai were founded walking on the ground or at light in July to October (Fig. 6C)