Planaeschna tamdaoensis Asahina, 1996

Kompier, Tom, Karube, Haruki, Futahashi, Ryo & Phan, Quoc Toan, 2021, The genus Planaeschna McLachlan, 1895 and its subgroupings in Vietnam, with descriptions of three new species (Odonata: Aeshnidae), Zootaxa 5027 (1), pp. 1-35 : 22-25

publication ID	https://doi.org/ 10.11646/zootaxa.5027.1.1
publication LSID	lsid:zoobank.org:pub:CCF10500-01A3-476C-A4BE-57161E164EBD
persistent identifier	https://treatment.plazi.org/id/03A687CB-FFD5-FFE6-E0E7-7502FB05F96E
treatment provided by	Plazi
scientific name	Planaeschna tamdaoensis Asahina, 1996
status

Treatment

9. Planaeschna tamdaoensis Asahina, 1996 View in CoL

( Figs 13 View FIGURE 13 , 14A, 14D–G View FIGURE 14 , 15D–E, 15H View FIGURE 15 )

Planaeschna tamdaoensis: Asahina (1996) View in CoL pp. 69–70, Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 (description of male); Do & Dang (2007) p. 79 (distribution map), p. 132 (checklist); Karube (2002a) p. 2, Fig. 8 View FIGURE 8 (distal segment of vesicle spermalis); Karube (2004) pp. 1–4, Figs 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 (redescription of male, description of female).

Materials examined. 1 ♂ 1 ♀, Mau Son, Lang Son Prov., 7-VI-2014 , TK leg.; 1 ♂ 1 ♀, same location and collector, 16-VIII-2014 ; 1 ♂, Pia Oac NP, Cao Bang Prov., 4-X-2014 , TK leg.; 1 ♂, same location and collector, 19-X-2014 ; 1 ♂, same location and collector, 31-V-2015 ; 1 ♂, same location and collector, 27-VI-2015 ; 1 ♂ 1 ♀, same location and collector, 12-IX-2015 ; 2 ♂♂, same location and collector, 3-X-2015 ; 6 ♂♂, Tam Dao NP, Vinh Phuc Prov., 27-VIII-2016 , TK leg.

Additional observations. 6 ♂♂ 2 ♀♀, Mau Son, Lang Son Prov., 16-VIII-2014 , TK; 1 ♂, Pia Oac NP, Cao Bang Prov., 11-X-2014 , TK; 4 ♂♂, same location and observer, 18-X-2014 ; 1 ♂, same location and observer, 17- VI-2015 ; 1 ♀, Pia Oac NP, Cao Bang Prov., 27-VI-2015 , TK; 1 ♀, Tam Dao NP, Vinh Phuc Prov., 27-VIII-2016 , TK.

Notes. Planaeschna tamdaoensis was until recently only known from Tam Dao NP near Hanoi in northern Vietnam, but with the discovery of populations in Lang Son Prov. and Cao Bang Prov. it is clear it occurs widely in northwestern Vietnam along the border with Guangxi, China. When Asahina (1996) described P. tamdaoensis , he did not consider P. suichangensis Zhou & Wei, 1980 , described from Zhejiang, China, as already pointed out by Wilson (2005), who suggested that P. tamdaoensis might be a junior synonym of P. suichangensis . Planaeschna suichangensis is one of the commonest Planaeschna species in southern China, ranging from Zhejiang to Guangxi ( Wilson 2005, pers. comm.; Zhang 2019). There are no morphological differences between these species, although there is some variation in populations ascribed to either species, for instance in the extent of the black mark on the antefrons. In most specimens this black mark reaches the lower margin of the antefrons, but apparently especially in some specimens of Vietnamese populations of P. tamdaoensis the black mark does not cover the lower margin. In addition, some individuals display a double greenish-yellow spot on the dorsum of S10, as for instance in Fig. 11e View FIGURE 11 in Wilson (2005) and in specimens from Pia Oac NP in Cao Bang Prov. of Vietnam, whereas S10 is all black in others. In immature specimens, S10 is largely yellow on the dorsum ( Fig. 13G View FIGURE 13 ). Apparently, this turns all black in some individuals while maturing, but in others, spots remain.

Karube (2002a) described P. gressitti Karube, 2002 from Guangdong and separated it from P. tamdaoensis based on differences in the structure of the apical segment of the vesica spermalis. At that time, P. suichangensis was known only from more northern Fujian and Zhejiang and was not considered in relation to P. gressitti . Karube (2002a: p. 3) stated that “This new species is closely related to P. tamdaoensis (…) particularly in body maculation. It is distinguished from the latter by having slenderer and more gently curved superior appendages, slenderer inferior appendage, distal segment of penis with a developed earlobes projection, and a broad and expanded apex on ventral part.” Zhang (2019) also mentions the difference in vesica spermalis as identification character for these otherwise identical species.

We would like to mention two observations regarding these diagnoses. The first is that the angle of the anal appendages when seen in lateral view greatly influences the visibility of the downward expansion and curvature of the cerci. Compare the different lateral view of Fig. 15D, E and H View FIGURE 15 from Vietnamese specimens of P. tamdaoensis . This illustrates our assertion that the apparent differences between the cerci of P. suichangensis , P. gressitti and P. tamdaoensis do not hold up: Fig. 15H View FIGURE 15 is identical to Fig. 15G View FIGURE 15 , which is taken from the illustration of P. gressitti in Zhang (2019), and Fig. 15E View FIGURE 15 is similar to the illustrations of P. suichangensis in Zhang (2019) and Wilson (2005) here depicted as Fig. 15B View FIGURE 15 and Fig. 15A View FIGURE 15 respectively. Likewise, Fig. 15D View FIGURE 15 is identical to the illustration of P. tamdaoensis in Asahina (1996: p. 70, Fig. 3a–b View FIGURE 3 ).

The second observation is that the apical part of the vesica spermalis in Planaeschna species consists of a soft double globular structure, often with distinct ears at the base, that dramatically changes shape upon preservation. This causes the globular shape to shrink and deform.

The remaining shape is sometimes slightly rounded in ventral view and sometimes completely slender and angular. This is illustrated in Fig. 14 View FIGURE 14 . The shape of the apical segment of a fresh specimen ( Fig. 14A View FIGURE 14 ) is compared with the various shapes of preserved specimens as depicted in Fig. 14E–H View FIGURE 14 . The more rounded shape ( Fig. 14C View FIGURE 14 ) as depicted for P. suichangensis in Karube (2002a), the more bloated shape of P. gressitti in the same publication ( Fig. 14B View FIGURE 14 ) and the slender and more angular shape of P. tamdaoensis ( Fig. 14D View FIGURE 14 ) can all be explained as variations caused by the preservation process. The direction and prominence of the ears is likewise altered by preservation. This suggests these three species may well concern a single, widespread species. If so, the name of P. suichangensis would take precedence. However, we would like to postpone drawing a definite conclusion on this matter until DNA samples of the concerned populations of P. suichangensis and P. gressitti are available for analysis.

Ecology. All populations of P. tamdaoensis in Vietnam were found at an altitude of approximately 1000 m asl., in heavily forested areas with small brooks and seeps. The earliest record is of an immature male hawking in the afternoon under trees along a clearing at Pia Oac NP on 31 May and the latest record is of 19 October, from the same area, indicating a flight period extending from at least late May to October. At Pia Oac NP it occurs with at least two other species ( P. crux and P. samurai ), and at Tam Dao NP with the locally common but apparently range-restricted P. tomokunii Asahina, 1996 .

Distribution. Endemic to Vietnam (Cao Bang Prov., Lang Son Prov., and Vinh Phuc Prov.)