Atrocalopteryx auco, Hämäläinen, Matti, 2014

Hämäläinen, Matti, 2014, Atrocalopteryx auco spec. nov. from Vietnam, with taxonomic notes on its congeners (Odonata: Calopterygidae), Zootaxa 3793 (5), pp. 561-572 : 562-566

Atrocalopteryx auco spec. nov.

( Figs. 1–9 )

Material studied: Holotype ♂: Vietnam, Lang Son province, Huu Lien, Lan Chau community, a sidestream of Boc stream, 21° 43’ 34’’ N, 106° 23’ 15’’ E; alt. ca 260 m, 9 June 2008, M. Hämäläinen leg. Deposited at RNMH (Leiden). Paratypes: 2 ♂, 1 ♀, same data as for the holotype; 1 ♂, Vietnam, Lang Son province, Huu Lien, Tan Lai community, 21° 40’ 40’’ N, 106° 22’ 42’’ E; alt. ca 220 m, 9 November 2013, Sebastien Delonglee leg.

Etymology. The specific epithet auco is named after Âu Cơ, a character in the Vietnamese mythology. Âu Cơ was a young, beautiful mountain fairy who fell in love with Lac Long Quân (the Dragon Lord of Lac). They married and she gave birth to an egg sac from which hatched a hundred children known collectively as the Bach Viet, the ancestors of the Vietnamese people. Âu Cơ is widely honoured as the mother of Vietnamese civilization.

Description of holotype male. Head: Eyes in living specimen dark brown above, pale greenish below ( Fig. 1 ; cf. Figs. 2 , 6–7 ). Labium largely yellowish brown, tips of lateral lobes black. Labrum black with yellow lateral spots; base of mandibles with pale spots (cf. Fig. 6 ). Clypeus, frons and vertex dark metallic green. Antennae black with the anterior surface of pedicel yellow. A distinct postocular tubercle is present on the occiput.

Thorax: Prothorax dark metallic green. Synthorax dark, lustrous metallic green with yellowish markings restricted to a distinct narrow yellow stripe on the lower half of metepimeron bordering the second lateral suture and to a yellow triangle on lower part of metinfraepisternum (cf. Figs. 4 , 7 ). Ventral side of synthorax dark. Legs black, middle and hind coxae with small yellowish markings. Hind tibiae distinctly curved, middle tibiae slightly curved ( Figs. 1 , 4 ).

Wings: Wings moderately broad; in hind wing the length/breadth ratio is 3.5. Both wings dark opaque brown throughout ( Figs. 1 , 4 ). Under surface with a distinct reddish brown sheen viewed from certain angles; on upper side the sheen is less distinct. On upper side all main veins and crossveins are dark. On underside of hind wing main veins paler and most crossveins yellowish (cf. Figs. 2 , 7 ), more distinctly so in basal half of wing. On underside of fore wing veins only paler than wing membrane at base; yellow crossveins occur only at base, except in costal and subcostal fields yellow crossveins present slightly apicad to nodus. Median space open, without crossveins. Cubital field with 17–18 crossveins in fore wing, 22– 22 in hind wing. Quadrangle with 13–15 crossveins in fore wing, 17– 15 in hind wing. Antenodals (the first series) 36–37 in fore wing and 31–33 in hind wing. Vein IR2 runs parallel with RA after its origin (cf. Fig. 8 ).

Abdomen shining metallic green on dorsum and on sides, except ventrolateral edge of S10 and fine ventral and caudal margins on tergites of S8–9 yellow. Underside dark with apical end of S3–7 obscurely paler, underside of S8–10 conspicuously yellow (cf. Fig. 9 ). Anal appendages black, with basal part of inferiors distinctly yellow; appendages of typical structure for genus. Penis similar to that of A. atrata .

Measurements (mm): Hind wing 40; abdomen (incl. appendages) 54.

Variation in male paratypes. One of the paratypes collected in 2008 is teneral, the other not fully mature (semi-mature). The paratype collected in 2013 is a mature specimen; Figs. 6–9 illustrate this specimen, which resembles the holotype in the colour of body and wings. In the teneral specimen the metallic colour of the body is already weakly developed, legs are brownish and wings pale brownish with distinct violet shine. In the semimature paratype the wings have greenish or violet iridescent sheen depending on angle of view, except on the wingtip; on upper surface the tip is blackish brown, but on under surface it has a distinct coppery sheen. The body colour of this paratype resembles that of the holotype. The venation in the paratypes is similar to that of the holotype, with insignificant variation in the numbers of crossveins and antenodals.

Measurements (mm): Hind wing 41–43; abdomen (incl. appendages) 53–56.

Description of female ( Figs. 3 , 5 ). Head: Eyes in living specimens above paler brown than in male, eyes below pale yellowish ( Fig. 3 ). Colour pattern of head similar to male, but yellow on labrum more extensive, not divided into two separate dots. A small postocular tubercle present.

Thorax: Metallic green, yellow on sides more extensive than in male. Also lower border of metepimeron and anterioventral edge of mesepimeron obscurely yellowish, and metinfraepisternum pale ( Fig. 5 ). Venter of synthorax pale brownish. Legs as in male.

Wings ( Figs. 3 , 5 ): Dark brownish throughout, but subhyaline at basal 1/4, below costal and subcostal fields. In some angles wings show slight iridescence. Underside of hind wing with pale veins and distinctly yellowish reticulation as in male. White pseudopterostigma in both wings, ventral border slightly curved in middle, extending length of 7–8 underlying cells. Length/breadth ratio in hind wing 3.45. Median space open, without crossveins. Cubital space with 21–22 crossveins in fore wing, 24–25 in hind wing. Quadrangle with 16–18 crossveins in fore wing, 19– 19 in hind wing. Antenodals (first series) 38– 36 in fore wing and 34–35 in hind wing. Position of IR2 as in holotype male.

Abdomen black with slight metallic shine; S8–9 with brownish dorsal stripe, lower 2/3rd of lateral side and venter of S8–9 brownish, S10 brownish throughout.

Measurements (mm): Hind wing 45; abdomen (incl. appendages) 52.

Distribution. So far known only at Huu Lien, Lang Son province, in northern Vietnam.

Notes on the habitat and biology. A. auco has been found along streams (3–7 m wide) with moderate flow in rather open surroundings in a valley (alt. ca 200–260 m) surrounded by limestone karst peaks. At the site where the holotype was collected a stream emerges from underground beneath a karst peak. The immediate surroundings are cultivated land, but at least in 2008–2009 there was a small bamboo thicket left, where these damselflies took shelter. The flight period of A. auco extends from early June to early December at least. The damselflies are alert and difficult to approach, unlike A. atrocyana , which are more docile.

Huu Lien has been designated as a nature reserve covering ca 120 sq km. Much of the area of the reserve is forested, but since the two valleys inside the reserve have a population of ca 3000 people, the forests in the reserve are suffering from continuing exploitation. In some sites A. auco can be seen together with A. atrocyana , which is locally abundant in Huu Lien. However, the latter species prefers shadier streams in good forest environments. It can often be seen in shady places away from streams.

Distinguishing characters. Male —Only two of the earlier known Atrocalopteryx species, A. atrata ( Figs. 10–11 ) and A. atrocyana ( Figs. 12–13 ), have completely opaque wings in the male sex. In all other species there are hyaline portions in the wings ( Figs. 14–17 ). The mature male of A. auco spec. nov. differs from the other two opaque-winged species by having yellowish crossveins on the under surface of the wings ( Figs. 2 , 7 ); the pale crossveins are present throughout the hind wing, but in the fore wing present only in the basal area, extending apicad to the nodus at the upper wing border. On the upper surface of both wings the crossveins are dark. Also in atrata and atrocyana the crossveins are dark coloured on the upper surface of the wings, but in these species the under surface of the wings does not have yellowish crossveins. In atrata and atrocyana there are obscurely pale longitudinal veins on the basal part of the under surface of wings. Moreover, at some angles the crossveins of the costal field look pale, but not yellowish. In atrocyana the wings are proportionally much broader than in auco and atrata . In mature males of atrocyana and atrata both surfaces of the blackish wings reflect a bluish metallic sheen in certain angles, but in atrocyana the bluish sheen is more conspicuous. In mature males of auco the upper surface of the wings is dark brown with a slight sheen, while the under surface reflects a reddish-brown sheen ( Fig. 1 ).

Auco male differs from the other two species by having the underside of abdominal segments 8–10 strikingly yellowish ( Fig. 9 ), the yellow extending along the lateroventral border of terga and covering part of the intersegmental rings of S8 and S9, lower half of sides of S10, and base of inferior appendages. In atrata and atrocyana these are all black. Unlike the other two species, in auco there is a short yellow stripe along the second lateral suture of the synthorax ( Fig. 7 ).

On the head of auco ( Fig. 6 ) there are two yellow lateral spots on the labrum and a yellow spot at the base of the mandibles. In atrata and atrocyana these yellow markings are absent. In auco there is a distinct postocular tubercle on the occiput, while in atrata the tubercle is absent and in atrocyana it is vestigial.

Female —The female of auco ( Fig. 3 ) can be easily separated from atrata and atrocyana by the presence of whitish pseudopterostigma in both wings; this is absent in atrata ( Fig. 18 ), atrocyana ( Fig. 19 ), and laosica . The females of both A. coomani ( Fig. 20 ) and A. melli ( Fig. 21 ) have quite similarly shaped white pseudopterostigma as auco , but the three species can be separated by characters presented in the key (p. 571). Moreover, auco female is smaller than the other two species, and in auco the yellow on metepisternum and metepimeron is more restricted.

Figures

FIGURES 1 – 3. Atrocalopteryx auco spec. nov. photographed in the field. 1) Male holotype photographed by Matti Hämäläinen at the type locality before it was collected; 2 – 3) Male (2) and female (3) photographed by Tom Kompier at Huu Lien (Tan Lai) on 17 November 2013. Specimens not collected.

FIGURES 4 – 5. Atrocalopteryx auco spec. nov. 4) habitus of holotype male; 5) habitus paratype female.

FIGURES 6 – 9. Atrocalopteryx auco spec. nov., paratype male photographed alive by Sébastien Delonglée on 9 November 2013. 6) head; 7) head, thorax and bases of wing; 8) details of venation at wing base; 9) tip of abdomen, lateroventral view.

FIGURES 10 – 15. Males of Atrocalopteryx species photographed in the field. 10) A. atrata, China, Guangdong, by Hao-miao Zhang; 11) A. atrata, Japan, Chiba by Roy Futahashi; 12 – 13) A. atrocyana, Vietnam, Lang Son, Huu Lien, by Sébastien Delonglée; 14) A. coomani, Vietnam, Hoa Binh, Thuong Tien, by Sébastien Delonglée; 15) A. melli, China, Guangdong, by Shan-lian Mo.

FIGURES 16 – 21. Atrocalopteryx species photographed in the field. 16) A. laosica male, Vietnam, Lao Chai, Sapa, by Cuong Do; 17) A. oberthueri male, China Yunnan, Dali, by Hao-miao Zhang; 18) A. atrata female, China, Guizhou, by Hao-miao Zhang; 19) A. atrocyana female, Vietnam, Lang Son, Huu Lien, by Matti Hämäläinen; 20) A. coomani, Vietnam, Hoa Binh, Thuong Tien, by Sébastien Delonglée; 21) A. melli, China, Guangdong, Nankunshan, by Hong-dao Wu.