Helophorus dracomontanus sp. n. is described from the Tibetan Plateau near Kangding, Sichuan, China. It is a member of the subgenus Helophorus s. str. but the anterolateral part of the pronotum resembles subgenus Gephelophorus Sharp, 1915. The short metallic-black maxillary palpi with almost symmetrical apical segments are suggestive of subgenus Kyphohelophorus Kuwert, 1886, but the elytral flanks are narrower than the epipleurs, excluding the species from that subgenus. An adjusted key to Helophorus s. str. is given to identify the new species, as well as H. jaechi Angus, 1995 and H. kozlovi Zaitsev, 1908.

Helophorus , Helophoridae , new species, Helophorus s. str., Meghelophorus , H. dracomontanus sp. n., H. jaechi Angus, H. kozlovi Zaitsev, Tibetan Plateau, China, Sichuan

In the course of a beetle-collecting trip to the Kangding area of Sichuan in June-July 2016, two females of an unknown Helophorus, apparently a robust member of the H. glacialis Villa & Villa, 1833 species group, were taken. Despite further searching, no male was encountered. Study of the material back in the laboratory showed that the elytra had scutellary striae, and this, in conjunction with the fairly narrow elytral flanks, indicated that it was a member of the subgenus Helophorus s. str. It is described here as it is sufficiently distinctive to be easily recognised from females alone.

Helophorus dracomontanus is placed in subgenus Helophorus s. str. because of its scutellary striae and elytral flanks not wider than the epipleurs. The suprapleural areas of the pronotum (pronotal epipleurs) are widest in basal quarter, distinctly narrower in front because of the sinuation of the lateral margins (Fig. 1c), and evenly narrowed to the hind angles. In this respect H. dracomontanus resembles the species of Gephelophorus Sharp, 1915. But in both of these (H. sibiricus Motschulsky, 1860 and H. auriculatus Sharp, 1884) the elytral flanks are at least as wide as the epipleurs. The metallic black maxillary palpi with almost symmetrical oval apical segments are shared by H. (H. s. str.) niger J. Sahlberg, 1880 and H. (H. s. str.) khnzoriani Angus, 1970, though the palpi are longer in these species, both of which have the pronota devoid of granulation. Neither of these species has the lateral margins of the pronotum sinuate behind the anterior angles. Its general appearance resembles a non-tuberculate H. (Kyphohelophorus) tuberculatus Gyllenhal, 1808 but in Kyphohelophorus the elytral flanks are much wider than the epipleurs.

Shining, often metallic, black maxillary palpi are fairly unusual in Helophorus. H. niger is associated with very dark substratum (e.g. Sahlberg 1880) and H. khnzoriani is a high-altitude species (Angus 1970), occurring in areas which are frequently dark and unvegetated after snow-melt, and this is also true of the H. glacialis Villa & Villa, 1833 and other species of the Helophorus glacialis and H. guttulus Motschulsky, 1860 species groups of the former subgenus Atractohelophorus Kuwert, 1886 (Angus et al. 2017). Finally, H. tuberculatus is typically found in recently burned (and thus) black areas and is a superb charcoal-mimic (Angus 1992). It therefore seems that these dark metallic palpi are associated with adaptation to dark ground, generally at high altitude or latitude.

In the key to the world species of Helophorus s. str. (Meghelophorus Kuwert, 1886) (Angus 1970), and also in the key to the Western Palaearctic species (Angus 1992), H. dracomontanus would run to couplet 8 because abdominal sternite 7 lacks square-ended teeth and the head has distinct granules over most of its surface. H. dracomontanus, as well as H. kozlovi Zaitsev, 1908 (not available when the 1970 key was written) and H. jaechi Angus, 1995 can be accommodated by substitution of a new Couplet 8 followed by three additional ones, 8’ – 8”’, as follows:

I thank Fenglong Jia for hosting my visit to China and for all his help, the Natural History Museum London and the Biology School of Sun Yat-sen University, Guangzhou for research facilities, Dandan Zhang for her help for booking hotel and flight tickets for the Kangding collection, Zhiqiang Li and Mr. Kai Chen for their help when we were working on field.