Description of Protosticta binhi sp. n. from the Central Highlands of Vietnam (Odonata: Zygoptera: Platystictidae)

Protosticta binhi sp. n. is described from the Central Highlands of Vietnam (holotype male: Vietnam, Gia Lai Province, K’Bang District, Dak Roong Commune, Dak Hro village, 14.36611° N, 108.4103° E, 1130 m asl, 22 May 2018, T.odo. 22051810, Zoological Collection of Duy Tan University). The new species can be easily distinguished from all other Protosticta species by the combination of huge body size, bird-head shape of cerci and paraprocts broad and apically armed with several sharp subapical projections in the male, and the anterior pronotal lobe of the prothorax well developed in the female. http://www.zoobank.org/urn:lsid:zoobank.org:pub:F047FB25-2B21-447D-8E4A-BA3A7DC77138

In this paper, we describe Protosticta binhi sp. n. from the Central Highlands of Vietnam. The combination of the bird-head shape of the cerci and the paraprocts armed with several sharp *Corresponding author. Email: pqtoan84@gmail.com subapical projections for the male, and the anterior pronotal lobe of the prothorax of the female, helps to easily separate Protosticta binhi sp. n. from its congeners.

Materials and methods
Specimens were collected in the field by hand net, placed in rectangular envelopes and steeped in 100% acetone for 8-12 hours before drying. Each specimen is preserved dry in a rectangular clear envelope with its data printed on the card backing each specimen.
The habitus of the holotype male and paratype female of the new species were photographed with a Nikon D3300 camera (Nikon factory, Ayuthaya, Bangkok, Thailand) with lens Nikon AFS DX Micro Nikkor 85 mm f/3.5G ED VR (Nikon factory, Ayuthaya, Bangkok, Thailand). Color photos of structures were taken by Axiocam Erc 5s on Zeiss Stemi 508 Stereo Microscope (Carl Zeiss AG, Oberkochen, Germany). Black and white illustrations were rendered using Adobe Photoshop 7.0 (Adobe Systems Incorporated, Mountain View, California, U.S.).

Etymology
The first author chose the specific name "binhi" after the last name of his father, Mr. Phan Dinh Binh (born in 1952) to whom he is grateful for his love and support. A noun in genitive case.

Type specimen deposition
All type specimens of the new species are deposited in the Zoological Collection of Duy Tan University, Danang, Vietnam.

Diagnosis
The bird-head shape of the cerci, the paraprocts longer than the cerci, broad and armed with several sharp subapical projections of the male are unique amongst Protosticta species; anterior pronotal lobe of prothorax of the female extends up and backward much further than in the known Protosticta females.

Description of holotype male
Head (Figures 3, 4). Labium pale yellow, tip with movable hooks black. Labrum, anteclypeus, postclypeus, mandibles and genae whitish, lower margin of labrum shining black. Frons matte black. Base of antennae black, the second segment brown, the third one yellow with a black apical ring, remaining segments entirely black. All ocelli surrounded by yellow. Epicranium matte black with a dark yellow occipital bar and two post-ocular spots. Occipital ridge black, either end with a small but distinct sharp spine. Thorax. Prothoracic pronotum as in Figures 7, 8. Anterior pronotal lobe slightly prominent in lateral view; posterior pronotal lobe dorsally black, posterior margin and two raised hind lobes yellowish. Lateral margin of all three lobes whitish, this forming a straight white line in lateral view (Figures 7, 10). Propleuron black. Synthorax black except for a large white mesepimeral stripe and another pale yellowish stripe on lower margin of metepimeron (Figure 1).
Legs. Coxae yellow, base of prothoracic legs with a brownish spot; trochanter yellow; femur yellow speckled with black in its flexor surface; tibia dark yellow, flexor surface black; tarsus yellow; claws and armature black.
Wings hyaline, light brown at apex. Px 17 in fore wing and 18 in hind wing. Pterostigma brownish.
Abdomen (Figure 1). Dorsal half of S1-2 black, the remainder pale yellow; S3 brown on top, pale yellow below, posterior 1/5th black; S4-6 black, pale ventral color extending upward to form an annulus anteriorly; S7 with basal third whitish, this stripe narrower than that of preceding segments, slightly broader posteriorly; S8 black except for a thin stripe connecting with whitish marking on S7; S9-10 entirely black. Figure 15, the tip with two short apical flagella each curved distally.

Description of paratype female
Color pattern as in holotype male, except for the following differences: Back of the head almost completely yellow with some dark smudges, two semicircular postocular streak broadly extending and touching two spots behind lateral ocelli ( Figure 6). Anterior pronotal lobe of prothorax much more prominent than that of male ( Figure 10). Wings with 15 Px in hind wing. S8 lacking a stripe but with yellow confined to ventrobasal portion of segment ( Figure 2). Cerci, stylus and tip of ovipositor pale yellow, remainder black.

Variation in paratype male and female
Paratype specimens show no significant differences from the holotype male and the female paratype used for description.

Habitat and ecology
The new species was found in a shaded shallow narrow (about 1-3 m width) forest mountain stream with slow running water, with a sandy bottom with many large rocks in Dak Hro village (1130 m asl).

Differential diagnosis
Among the genus Protosticta Selys, 1855, the new species and P. robusta Fraser, 1933, P. grandis, P. taipokauensis Asahina & Dudgeon, 1987 and P. ngoai share a similar robust body size, black synthorax with two distinct yellow/whitish stripes and pale yellow/white labrum and appendages (the labrum of the holotype P. ngoai was described as black (Phan & Kompier 2016  but based on our subsequent observation this appears to be an aberration). The male of Protosticta binhi differs from P. grandis, P. ngoai and P. taipokauensis (note that P. robusta is only known from a single female) by the following characters: cerci shaped like a bird's head, paraprocts longer than cerci, broad and armed with some sharp subapical projections (Figures 11-13) whereas these are roundly apically, shorter or pointed apically but lacking subapical projections in P. grandis, P. ngoai and P. taipokauensis (figures 3B, 4C, 4I in Phan & Kompier 2016). The anterior pronotal lobe of the female prothorax of P. binhi sp. n. is distinctive, elongated upwards and backwards ( Figure 10), but lacks such elongation in the holotype female of P. robusta ( Figure  18) as well as in P. grandis (figure 3G in Phan & Kompier 2016) and P. taipokauensis (figure 4 in Asahina & Dudgeon 1987).

Discussion
Protosticta robusta Fraser, 1933, characterized by its high numbers of postnodal crossveins in both wings (22 in forewings and 20 in hind wings) (Figure 16), was described from Laos based on a single female (Fraser 1933). The high numbers of crossveins in forewings of the holotype specimen of P. robusta is considered unique with P. grandis, P. ngoai and P. taipokauensis having just 16-19 Px, but Kompier (pers. comm.) collected a male of P. ngoai sensu Phan & Kompier from Tam Dao National Park, northern Vietnam with 21 Px in both wings and some specimens of P. grandis sensu Asahina from Bach Ma National Park and Lam Dong Province, all central Vietnam, with 20 Px. This indicates there is considerable variation in the number of postnodal crossveins in these species, one of which may well be conspecific with P. robusta.
According to Phan and Kompier (2016), the male of Protosticta grandis in Vietnam is easily separated from P. ngoai and P. taipokauensis by its broad cercal tips (figures 3B, 4C in Phan & Kompier 2016). P. grandis or P. ngoai or even P. taipokauensis may be a junior synonym of the P. robusta, given that they were all described without knowledge of the variability of Px amongst this group and no other differential characters were established to separate these species from P. robusta (Asahina, 1984;Asahina & Dudgeon 1987;Phan & Kompier 2016). Indeed, we could verify no reliable characters by which to differentiate the holotype female of P. robusta  from the examined specimens of P. grandis sensu Asahina from Vietnam (see Phan & Kompier 2016) and P. ngoai sensu Phan & Kompier from Vietnam (see Phan & Kompier 2016) and Laos (1 ♂, 2 ♀, Vang Vieng, Laos, 19 April 2002; 1 ♂, 1 ♀, Oudomxay, Laos, 2 May 2009; 2 ♂, Lak Sao, Laos, 20 May 2016, all collected by Naoto Yokoi) in this study. As mentioned above, it will require further study to settle the taxonomic status of P. grandis, P. ngoai and P. taipokauensis. That would require, apart from the study (including molecular analysis) of a wide geographical range of additional material, the examination of the type specimens of grandis and taipokauensis. Settling this issue is further hampered by the fact that the male of P. robusta is still unknown. Collecting at the type locality in Laos of specimens would be highly beneficial to settle the taxonomic relationships between P. robusta, P. grandis, P. ngoai and P. taipokauensis in the future.