Protosticta nigra Kompier, 2016, spec. nov.
Creators: name: Kompier, Tom
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Platystictidae
Protosticta
Protosticta nigra

description: Protosticta nigra spec. nov.
(Fig. 12–14)
Etymology. The adjective nigra in the specific name means black and refers to the blackish thorax (Fig. 13) of the species.
Van Tol (2008) provided thorough descriptions of both light and dark form of P. s a t o i. The dark form was described based on specimens from Tam Dao National Park, Vinh Phuc Province, whereas the description of the light form (Figs. 15-16) was based on specimens collected in Cuc Phuong National Park, Ninh Binh Province. Both provinces are located in the north of Vietnam. The type specimen (a female) on which Asahina (1997) had based his description of P. khaosoidaoensis satoi (which currently cannot be located) had been collected from Tam Dao. The description he provided is rather limited but mentions three characteristics: 1) the prothorax has a large broad black area on the posterior lobe, 2) the black stripe over the metapleural suture is only weakly darkened, 3) S9 is adorned by a large pale bluish spot. From the accompanying drawings it is clear that the “large pale bluish spot covers about three-fifths of the dorsal side of S9 and does not extend laterally towards the ventral margin. This combination of characteristics only fits the female of P. s a t o i light form sensu van Tol amongst species known from northern Vietnam. Tam Dao National Park covers a large area but has been developed rapidly in the area where sampling took place in the nineties. It is certainly possible that P. s a t o i light form sensu van Tol occurred in what is now Tam Dao Town. I am convinced, based on the match between the characteristics listed by Asahina for the type of P. khaosoidaoensis satoi and the species from Cuc Phuong, that van Tol’s identification of his specimens of Cuc Phuong as P. satoi was justified.
Both forms occur widely in northern Vietnam (Phan & Kompier 2016), but based on many observations it can be concluded that the two forms never occur side by side at the same locations. Most commonly they do not even occur in the same general areas. The dark form, for instance, does not occur in Cuc Phuong, whereas I have not been able to relocate the light form in Tam Dao, where the dark form (Fig. 12) is common. In Ba Be National Park, Bac Kan Province, both forms occur, but at very different locations.
In their treatment of known Protosticta from Vietnam Phan & Kompier (2016) followed the original interpretation that these forms belonged to one species. But with increasing insight into the high diversity of the P. curiosa group of species in Vietnam a reassessment seemed necessary.
Although in lateral view differences between the appendages of the two forms seem minimal, close inspection in dorsolateral view does reveal consistent differences (Figs. 14, 17). Having said that, within the light form there is still some variation, both in shape of the cerci (presence of absence of dorsal tooth halfway) and pattern of the prothorax. However, they all share the same thoracic pattern (Figs. 18–19), and the general structure of the cerci is also similar. These differences seem too weak to warrant further division. In Table 1 the main differences between the cerci of P. s a t o i and P. ni g r a spec. nov. are summarized. Obviously the differences in patterning of the thorax are evident and do not warrant further elaboration.
Van Tol (2008) suggested that dark form P. s a t oi (= P. nigra spec. nov.) and dark form P. beaumonti Wilson, 1997, may in fact be the same taxon. Phan & Kompier (2016) published first records of P. beaumonti for Vietnam. Although morphological differences appear to be slight (prominence of teeth on cerci), they pointed to two differences in patterning between P. satoi dark form (= P. nigra spec. nov.) and P. beaumonti. Of these the thoracic pattern with a large white area on the posterior half of the metepisternum is most characteristic. The difference in patterning on S9 for the females in fact does not provide a good character to separate P. beaumonti from P. nigra spec. nov., which also has dark S9. In view of van Tol’s suggestion regarding the conspecificity of these two dark species, it is advisable to support the slight differences in morphology and thoracic patterning with a detailed molecular study in the future. For now we treat P. beaumonti dark form as separate from P. n i gr a spec. nov.
description: Published as part of Kompier, Tom, 2016, New species of Protosticta Selys from Vietnam with a key to the males of the P. curiosa group (Odonata: Platystictidae), pp. 347-360 in Zootaxa 4193 (2) on pages 354-356, DOI: 10.11646/zootaxa.4193.2.9, http://zenodo.org/record/166958