Neocerambyx katarinae guangxiensis Li, Lu & Chen, 2020

Neocerambyx katarinae guangxiensis Li, Lu & Chen, 2020 n. status.

( Fig. 3)

Li et al. (2020) described Neocerambyx guangxiensis from China comparing it with the Laotian N. katarinae Holzschuh, 2009 ( Fig. 4). The paratypes of this species ( Fig. 3) came from Guangdong (Nanling Reserve) even if this locality was erroneously quoted as “ Guangxi.” Differential characters separating is from N. katarinae were listed as shorter and more inflated antennomere III in males, the more transverse wrinkles of the pronotum, the different tergite VIII and in the longer antennae of females.

Holzschuh (2021) proposed that N. guangxiensis was synonym of N. katarinae and claimed that antennomere III is normally more inflated in small males of N. katarinae , the pronotum shows a variable sculpture and the female antennae vary enormously.

Holzschuh based the synonymy on the examination of 20 specimens of N. katarinae but only one female coming from Guangxi , and no males from Guangxi nor specimens from Guangdong.

Additionally, Holzschuh’s (2009) original description did not indicate this great variability but only relative characters (a bit shorter, a bit stronger, a bit longer, etc.) separating it from Neocerambyx grandis Gahan, 1891 . Among the differential characters, Holzschuh also indicated the absence of the smooth area on the pronotal disc, which is actually absent in N. grandis as well (cf. Gahan, 1906: 125-126, fig. 48; Miroshnikov, 2018: fig. 25).

Agreeing that the pronotal sculpture is a poor character to differentiate N. guangxiensis from N. katarinae (as it is for differentiating N. katarinae from N. grandis ), no sufficient elements (two known specimens) allow understanding whether the antennal length of females is a constant character.

Nonetheless, the observation regarding antennomere III is completely unfounded. In fact, Holzschuh overlooked the fact that the paratype of N. guangxiensis ( Li et al., 2020: fig. 1d) is not at all a small specimen, but 72 mm long, and shows the same character as the small holotype ( Li et al., 2020: fig. 1a). This paratype ( Fig. 3) was also compared with a relatively smaller (67 mm) N. katarinae ( Fig. 4), which shows a less inflated antennomere III ( Li et al., 2020: fig. 3b); thus, exactly the opposite of Holzschuh’s observation. Therefore, this character is in reality independent from body size.

Moreover, this paratype shows shorter antennae in comparison with this smaller specimen of N. katarinae (antennomere VIII reaches the visible urite III in N. guangxiensis , while it reaches urite IV in N. katarinae ). This contrasts with the well-known fact that there are allometric relationships between antennal length and elytra length in male cerambycids, i.e., larger conspecific specimens should show comparatively longer antennae ( Rossi de Gasperis et al., 2018).

Another specimen from Guangxi (Wuming Co. Liangiang, coll. S. Trócoli, 64 mm long) confirms the same characters regarding length and size of antennomere III .

Finally, Holzschuh completely ignored the different shape of tergite VIII: sinuate and strongly bilobed at the apex in N. guangxiensis vs. nearly evenly rounded in N. katarinae .

The type localities are separated by 570–1030 km and N. katarinae is also widespread in northeast India, Vietnam and even in Guangxi (Miroshnikov, 2018). This last record might also be referred to specimens of N. guangxiensis , which was still undescribed at that time, as well as the male depicted in Hua et al. (2009: pl. 43, fig. 506), originally identified as “ N. grandis ” or “ N. katarinae ” (Miroshnikov, 2018) . Nonetheless, Li et al. (2020) also depicted N. katarinae from Guangxi.

In conclusion, N. guangxiensis is a taxon smaller than N. katarinae (53.8–72 vs. 68–76 mm), with more inflated antennomere III (independently from body size), shorter antennae (comparing specimens of the same body size), different shape of tergite VIII and north-eastern distribution (Guangxi, Guangdong). Both taxa are present in Guangxi (even though the exact local distribution is unknown) but not in other provinces.

In my opinion, there are not sufficient elements to prove neither that N. guangxiensis is synonym of N. katarinae nor that it is a well differentiated species, as for example N. grandis is. Thus, waiting for further specimens, the provided elements suggest considering N. guangxiensis a north-eastern subspecies of N. katarinae .