Platynectes gemellatus Šťastný, 2003

Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), Zootaxa 5227 (4), pp. 401-425 : 408-409

Platynectes gemellatus Šťastný, 2003

( Figs 3B–C , 6J–O , 8B, D , 11A )

Platynectes gemellatus Šťastný, 2003: 235 (orig. descr.); Liu 2020: 32 (descr.).

Type locality. “ China, Hong Kong ” .

Type material. Holotype ♂, deposited in NHMW.

Material examined. CHINA: Guangdong: 1 ♂, 2 ♀, Fengkai, Heishiding , 10.iv.1985, W. Wu leg. ( SYSU) ; 3 ♀, Fengkai, Heishiding , 2.v.2011, F. Jia leg. ( SYSU) ; 2 ♀, Lian County, Dadongshan Mt. , 7.vii.1995, F. Jia & Y. Liu leg. ( SYSU) ; 1 ♂, 4 ♀, Lian County, Dadongshan Mt. , 22.vi.2004, X. Fang leg. ( SYSU) ; 1 ♂, Nanling, Dadongshan Mt. , vi.2004, F. Jia leg. ( SYSU) ; 2 ♂, 1 ♀, Lian County, Dadongshan Mt. , 6.vii.2008, F. Jia leg. ( SYSU) ; 2 ♀, Nanling, Dadongshan Mt. , 23-27.vi.2009, F. Jia leg. ( SYSU) ; 3 ♂, Shaoguan, Chebaling, Fanchifeng , 24°42′9″N, 114°11′10″E, 485 m, 20.viii.2020, Z. Yang leg. ( SYSU) ; 4 ♂, 5 ♀, Shaoguan, Chebaling Nature Reserve , 24°43′6″N, 114°15′8″E, 450 m, 21.viii.2020, Z. Yang leg. ( SYSU) ; 2 ♂, 2 ♀, Huizhou, Longmen County, Nankunshan Reserve , 23.6349N, 113.8409E, 550 m, 23.iii.2021, Z. Jiang leg. ( SYSU) ; 5 ♂, 3 ♀, Huizhou, Longmen County, Nankunshan Mt. , Gaoshanbieshu , 23.6249N, 113.8709E, 640 m, 7-9.vii.2021, Z. Jiang, Z. Mai & Z. Liang leg. ( SYSU) ; 3 ♂, 3 ♀, Guangzhou, Conghua distr., Liuxihe , Wuzhishan Scenic Spot , 23.7339N, 113.8075E, 295 m, 26.iii.2021, Z. Jiang leg. ( SYSU) ; 3 ♂, 4 ♀, Ruyuan, Nanling , mid-mountain protection station, 1000m, 23.viii.2010, S. Zhao leg. ( SYSU) ; 3 ♂, 1 ♀, Shaoguan, Ruyuan County, Nanling , Ruyang Management Station , 24.9281N, 113.0177E, 980 m, 2.xi.2021, Z. Mai leg. ( SYSU) ; 1 ♂, 1 ♀, Shaoguan, Ruyuan County, Nanling , Laopengyidui , 24.9304N, 113.0131E, 1050 m, 3.xi.2021, Z. Mai leg. ( SYSU) ; 3 ♂, Shaoguan, Ruyuan County, Nanling , 24.9252N, 112.9800E, 1600 m, 4.xi.2021, Z. Mai leg. ( SYSU) ; Hongkong: 1 ♂, Dabujiao ( Hexi ), 22°25.697′N, 114°10.834′E, 145 m, 10.iv.2014, F. Jia, W. Xie & J. Chen leg. ( SYSU) ; 1 ♂, 1 ♀, Rongshuao , 22°32.646′N, 114°14.926′E, 10 m, 11.iv.2014, F. Jia, W. Xie & J. Chen leg. ( SYSU) ; 2 ♂, 1 ♀, Fengkeng , 22°31.695′N, 114°13.450′E, 13 m, 9.vi.2014, F. Jia, W. Xie & J. Chen leg. ( SYSU) ; 1 ♂, Rongshuao , 22°25.641′N, 114°17.410′E, 10 m, 11.vi.2014, F. Jia, W. Xie & J. Chen leg. ( SYSU) ; 1 ♂, Datan ( Lejuyuan ), 22°15.513′N, 114°12.163′E, 240 m, 13.vi.2014, F. Jia, Y. Li & J. Chen leg. ( SYSU) ; 1 ♀, Shaluodong , 22°28.555′N, 114°10.909′E, 185m, light trap, F. Jia, W. Xie & Alex leg. ( SYSU) ; Hunan: 3 ♂, 4 ♀, Shaoyang, Chengbu County, Baimaoping Town , Xiatang Road , 26.2643N, 110.3585E, 530 m, 23.viii.2020, night & light trap, Z. Jiang leg. ( SYSU) ; 1 ♀, Shaoyang, Chengbu County, Jinzishan forest farm, Yaorenping , 26.2524N, 110.4976E, 825 m, 25.viii.2020, day, Z. Jiang leg. ( SYSU) ; 3 ♂, 1 ♀, Shaoyang, Chengbu Miao Autonomous County, Lanrong Township , Jintongshan Mt. , 26°17′51″N, 110°28′58″E, 1095 m, 8.ix.2020, Z. Yang leg. ( SYSU) ; 1 ♀, Shaoyang, Chengbu Miao Autonomous County, Lanrong Township , Jintongshan Mt. , 26°14′64″N, 110°22′25″E, 565 m, 8.ix.2020, light trap, Z. Yang leg. ( SYSU) ; 3 ♀, Chenzhou, Mangshan Mt. , Jiangjunzhai, 24°57′1″N, 112°55′58″E, 1260 m, 27.viii.2020, Z. Yang leg. ( SYSU) ; 1 ♂, Chenzhou, Yizhang County, Mangshan Mt. , 24.9457N, 112.9824E, 1480 m, 5.ix.2020, Z. Ma leg. ( SYSU) ; Jiangxi: 7 ♂, 3 ♀, Jinggangshan Mt., Jingzhushan Scenic Area , 4.x.2010, S. Zhao leg. ( SYSU) ; 3 ♂, 1 ♀, Jinggangshan Mt., Shuangxikou , 5.x.2010, S. Zhao leg. ( SYSU) ; 2 ♂, 1 ♀, Jinggangshan Mt., Shuangxikou , 24.iv.2011, S. Zhao leg. ( SYSU) ; 1 ♀, Jinggangshan Mt., Huyangta , 28.iv.2011, S. Zhao leg. ( SYSU) ; 11 ♂, 8 ♀, main peak of Jinggangshan Mt. , 605 m, 29.iv.2011, S. Zhao leg. ( SYSU) ; 1 ♂, Jinggangshan Mt., Xiazhuang , 29.iv.2011, S. Zhao leg. ( SYSU) ; 1 ♀, Jinggangshan Mt. , 1.iv.2011, Y. Li leg. ( SYSU) ; 1 ♂, Jinggangshan Mt., Xiangzhou , 28.v.2011, L. Yang leg. ( SYSU) ; 16 ♂, 8 ♀, Ganzhou, Jiulianshan Mt., Xiagongtang , 24°32′28″N, 114°27′32″E, 525 m, 18.viii.2020, Z. Yang leg. ( SYSU) ; Macao: 1 ♂, Luhuan, Zhugutang , 27.iii.2014, W. Xie leg. ( SYSU) ; 5 ♂, 6 ♀, Luhuan, Dieshitang , 27.iii.2014, F. Jia, W. Xie & J. Wang leg. ( SYSU) ; Zhejiang: 1 ♂, Quzhou, Kaihua County, Gutianshan Nature Reserve , 29.2499N, 118.1402E, 695 m, 20.ii.2021, Z. Jiang & X. Ye leg. ( SYSU) .

Notes. Habitus and male genitalia are given in Figs 3B–C and 6J–O .

Collection details. The specimen from Gutianshan Nature Reserve was collected together with P. dissimilis among decaying leaves in a stream ( Fig. 8B ); in Liuxihe, specimens were also collected in small shallow puddles on a mountain dirty road ( Fig. 8D ).

Distribution. Southern and eastern China (Fujian, Guangdong, Guangxi, Guizhou, Hunan, Hongkong, Jiangxi, Macao, Taiwan, Zhejiang) ( Fig. 11A ). First record from Hunan and Zhejiang provinces.

Notes. During field collections by the senior author in Gutianshan Mt. (Zhejiang), it was observed that P. gemellatus and P. dissimilis were living together in the same place of the same stream. However, P. gemellatus is much rarer than P. dissimilis here, probably because drifting through the water facilitates dispersal. At other localities both species probably do not occur in the same habitat. These two species may have different ecological requirements, but this needs to be confirmed by more observations in the future.

Specimens of both species from Gutianshan Mt. are easy to distinguish, in P. gemellatus with elytral yellow vittae not reduced basally ( Fig. 3C ) and apex of median lobe of aedeagus less pointed ( Fig. 6M ), and in P. dissimilis with elytral yellow vittae vanishing on basal third of elytra ( Fig. 3A ) and apex of median lobe of aedeagus more pointed ( Fig. 6H ). However, when the full spectrum of the colour range is considered, P. gemellatus can closely resemble P. dissimilis ( Fig. 2C ). Except for the shape of the median lobe of aedeagus, other characters such as body size and aspect of longitudinal grooves on male abdominal ventrite VI are not stable and cannot be used reliably for identification. Even the shape of the median lobe of aedeagus of specimens of these two species from different areas is somewhat variable ( Figs 6E–H, 6J–N ), and there are intermediate forms difficult to distinguish. In addition, fully coloured specimens of P. dissimilis may also occur syntopically with P. gemellatus as that in Gutianshan Mt. stated above, which increases the difficulty.

Figures

FIGURE 2. Habitus of Platynectes species. (A) P. babai Satô (♂; Kaohsiung, Taiwan); (B) P. davidorum Hájek et al. (♂; Yaowangshan, Zhejiang); (C) P. dissimilis (Sharp) (♂; Dinghushan, Guangdong); (D) P. dissimilis (Sharp) (♂; Yunhe Village, Hunan). Scale bar = 2.0 mm.

FIGURE 3. Habitus of Platynectes species. (A) P. dissimilis (Sharp) (♂; Gutianshan, Zhejiang); (B) P. gemellatus Šťastný (♂; Nanling, Guangdong); (C) P. gemellatus Šťastný (♂; Gutianshan, Zhejiang); (D) P. hainanensis Nilsson (♂; Limushan, Hainan). Scale bar = 2.0 mm.

FIGURE 6. Male genitalia of Platynectes species. (A, C, E–H, J–N) median lobe in lateral view; (B, D, I, O) paramere. (A–B) P. babai Satô (Kaohsiung, Taiwan); (C–D) P. davidorum Hájek et al. (Yaowangshan, Zhejiang); (E) P. dissimilis (Sharp) (Dinghushan, Guangdong); (F) P. dissimilis (Sharp) (Huaping, Guangxi); (G) P. dissimilis (Sharp) (Yunhe Village, Hunan); (H–I) P. dissimilis (Sharp) (Gutianshan, Zhejiang); (J) P. gemellatus Šťastný (Rongshuao, Hongkong); (K) P. gemellatus Šťastný (Baim- aoping Town, Hunan); (L) P. gemellatus Šťastný (Jinggangshan, Jiangxi); (M) P. gemellatus Šťastný (Gutianshan, Zhejiang); (N–O) P. gemellatus Šťastný (Nanling, Guangdong). Scale bars = 0.5 mm.

FIGURE 8. Habitat of Platynectes species. (A) Yaowangshan, Zhejiang (P. davidorum); (B) Gutianshan, Zhejiang (P. dissimilis & P. gemellatus); (C) Tianpu Village, Zhejiang (P. dissimilis); (D) Liuxihe, Guangdong (P. gemellatus).

FIGURE 11. Maps of distribution of Platynectes species in China. (A) P. gemellatus; (B) P. hainanensis.