Chu, Tian & He, 2020
|
publication ID |
https://dx.doi.org/10.3897/zookeys.1008.61040 |
|
publication LSID |
lsid:zoobank.org:pub:E17BB2E7-12A9-4F42-9595-6082848B8FC9 |
|
persistent identifier |
https://treatment.plazi.org/id/323F87B4-17A4-48F4-B816-8423C9011A68 |
|
taxon LSID |
lsid:zoobank.org:act:323F87B4-17A4-48F4-B816-8423C9011A68 |
|
treatment provided by |
|
|
scientific name |
Chu |
| status |
gen. nov. |
Chu gen. nov. Chinese name: 初盲步甲属 Figs 2 View Figure 2 , 4B, D View Figure 4 , 5C, D View Figure 5 , 7 View Figure 7 , 8 View Figure 8
Type species.
Chu pheggomisetoides sp. nov., from the limestone cave Hanwang Dong in Guangyuan, northeastern Sichuan.
Generic characteristics.
Medium-sized, somewhat similar to the Balkan genus Pheggomisetes Knirsch, 1923 in appearance especially head and pronotum (Fig. 7 View Figure 7 ); anophthalmic and depigmented; body moderately elongate, with rather thin and slender appendages. Head strongly expanded laterally and convex though shorter than long, two pairs of supraorbital setiferous pores present; frontal furrows long and well-marked; labrum widely emarginated at front, mandibles widened and developed, apices strongly hooked, right mandibular tooth tridentate; labial suture visible at side, completely disappeared medially (Fig. 4B View Figure 4 ); mentum bisetose, base largely concave, submentum 8-setose; antennae thin and very long, extending over apices of elytra. Propleura invisible from above; pronotum subcordate, transverse, hind angles very sharp and distinctly protruded backwardly which is similar in Pheggomisetes , only presence of the anterior pair of latero-marginal setae. Elytra elongated ovate, twice as long as wide, much longer than fore body; prehumeral angles rounded off; lateral margins well-bordered throughout, finely ciliate on shoulders, whereas smooth on other parts; disc moderately convex, striae noticeable though distinctly reduced; two pairs of dorsal and the preapical setiferous pores present; the humeral group of the marginal umbilicate pores not aggregated, the 1st pore inwardly shifted to the site of 7th stria, only the 2nd pore closest to marginal gutter, 4th shifted posteriad; 5th and 6th pores closely spaced (Fig. 4D View Figure 4 ). The 1st and 2nd protarsomeres modified in male, distinctly widened and bluntly denticulate inward at apices, and with spongy setae ventrally. Ventrite VII with one pair of apical setae in male, whereas two pairs in female. Male genitalia with median lobe almost straight, suddenly widened at apical part; in lateral view, apex notched dorsally (Fig. 5C, D View Figure 5 ).
Remarks.
Although Chu gen. nov. resembles the Balkan cavernicolous genus Pheggomisetes Knirsch, 1923 ( Knirsch 1923; Vrbica et al. 2017) in the shape of head and pronotum, this must be a case of convergence because the faunas in the Balkan Peninsula and China are completely different. Indeed, there are many cases of large gaps in cave trechines between Europe and China, e.g., Doderotrechus from Western Italy vs. Trechus of the dacaitranus group ( Trechus bastropi ) from Tibet ( Faille et al. 2013). Apart from the similarities of the head and pronotum, both Chu and Pheggomisetes are very different in many aspects including outlines of head, prothorax and elytra, and in particular the chaetotaxic pattern on head and elytra.
As the fauna of subterranean ground beetles are still not well known, the phylogenetic position of Chu gen. nov. among Trechini is unknown at present, like many other genera. Its peculiar characters, such as ellipsoidal head with deep emarginated labrum, stout mandible, subcordate pronotum with sharp and backwardly protruded hind angles, and almost straight median lobe which is enlarged and notched at the apex isolate Chu gen. nov. from all other Chinese trechines. Beside comparative morphological study, evidence from molecular analysis would be valuable in determining its position.
Etymology.
" Chu " means "the first time" in Chinese, suggesting that this species was the first subterranean beetle discovered by Li He (the second author). Gender masculine.
Generic range.
China (Sichuan) (Fig. 2 View Figure 2 ). Monospecific genus, known only from the cave Hanwang Dong in Chaotian, Guangyuan.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.