Gynacantha cattienensis, Kompier, Tom & Holden, James, 2017

Kompier, Tom & Holden, James, 2017, A new species of Gynacantha Rambur, 1842 from Cat Tien National Park, Vietnam (Odonata: Aeshnidae), Zootaxa 4272 (3), pp. 411-420 : 411-420

Gynacantha cattienensis spec. nov.

( Figs. 1–3 , 5 A–B, D, F, 6)

Type specimens. Holotype: ♂, Forest Floor Lodge garden, Cat Tien National Park, Dong Nai Province, southern Vietnam (11.436 N, 107.428 E) , 06.II.2016, T. Kompier leg. Paratype ♀ used for description: same location , 03.X.2016, J. Holden leg. Paratypes: 1♂, same location, date and collector as holotype male . 1♀,: same location, 28.XII.2015, J. Holden leg. ; 1♀: same location, 01.I.2016, T. Kompier leg. ; 4♂ 2♀, same location and collector, 29.I.2017.

Etymology. The adjective cattienensis in the specific name refers to the type location, Cat Tien National Park in Dong Nai Province in Vietnam.

Description of male holotype ( Figs. 1 A, 5A, D). Head. ( Fig. 1 A) Labium, labrum, mandibles and anteclypeus orange-yellow, postclypeus and antefrons yellow, postfrons yellow with clear blackish-brown T-spot, the T-bar three times as wide as the stem. Vertex black, antennae orange-brown, occiput yellowish brown. Compound eyes (when alive) purplish blue dorsally, shading to blue towards the posterior edge and downwards, then becoming grayish with darker spots. Prothorax. Olive-green, covered in pale pruinosity. Synthorax. ( Fig. 1 A) Olive-green, somewhat grayish on mesepisternum and towards coxae, and with very thin brownish line over metapleural suture. Mesinfraepisternum yellow. Pale blue spots on dorsum between wings. Legs. ( Fig. 1 A) Femora of first pair of legs pale yellowish brown on inside and blackish brown on outside, remainder of leg dark brown. Second and third pairs with orange brown base to femora, remainder blackish brown. Wings. Strongly tinted brownish. Dark brown basal streak along subcosta in costal and subcostal space, extending to fourth antenodal crossvein in forewing and third antenodal crossvein in hindwing. Veins brown. Membranule pale. Anal triangle 3-celled, anal loop 9–10 celled. Forewing triangle 6 celled, hindwing 5–6 celled. Crossveins forewing 17–25:27–18 and hindwing 20– 18:17–20. Pterostigma pale brown, covering 5 cells in all wings. Abdomen. S1 pale brown, mottled with grey, laterally indistinct greenish spot towards posterior margin, S2 largely dark blue, mottled with grey, more olive towards dorsum, more green in front of auricles, auricles clearest blue, in ventral view with 2–4 distinct teeth. S3 anterior half brown dorsally and blue ventrally, posterior half blackish brown, with almost imperceptible paired mediodorsal (MD) and posterodorsal (PD) spots, S4–6 very dark brown with almost imperceptible paired MD and PD spots, S7–8 blackish brown with almost imperceptible MD spots, S9–10 blackish brown. Caudal appendages ( Fig. 5 A, D). Blackish brown. Cerci approximately 3.5 times length of S10. Proximal four-sevenths in dorsal view parallel sided, then expanding in width, bulging inward to almost 1.5 times original width, then smoothly curving and narrowing, outer edge remaining almost straight, until forming a distal spine that curves somewhat inwards again. In lateral view slightly curved downward from base to tip, bulging noticeably dorsally after four-sevenths of their length, then narrowing again and ending in distal spine. Epiproct in dorsal view thinning constantly from base to apex until one-fifth of original width, reaching to two-thirds of cerci. In lateral view smoothly curved down, then up, lowest point just before one-third of its length and apex hidden again between cerci.

Variation in paratypes ( Figs. 2 D, 5B, F). Auricles ( Fig. 5 F) with 4 distinct teeth, sometimes (2 specimens) a smaller 5th on one auricle. Dark streak along costa variably reaching second to fourth antenodal crossvein, anal loop 8–13 celled, triangles in hindwing 6 celled (once 5), forewings 6–8 celled. 25–30 antenodal crossveins and 18–22 postnodal crossveins in forewing, 19–22 antenodal and 19–23 postnodal crossveins in hindwing. In one male black of T-spot extending down over dorsal third of antefrons.

Holotype and all paratypes aged individuals. Hence the patterning on the abdomen is largely obscured. Photos of fresher individuals ( Figs. 2 A, C, 3A) reveal additional characters as follows: Thorax brighter green. Abdomen more clearly marked: S2 dorsally green and brown, with distinct but narrow green central line, separated from, but accompanied by two elongated triangular MD spots and virtually continuous green elongated spot along posterior margin. S3 with two narrow elongated green MD spots and two small rounded green PD spots, S4–6 with clear, elongated green MD spots and progressively vaguer green more rounded PD spots, S7–8 with indistinct elongated MD spots only. Wings hyaline, but with some amber at base in addition to dark streaks along subcosta.

Description of female ( Fig. 6 ). Head. Labium, labrum, mandibles and anteclypeus orange-yellow, postclypeus and antefrons yellow, postfrons yellow with clear blackish-brown T-spot, the T-bar three times as wide as the stem. Vertex black, antennae orange-brown, occiput green. Eyes purplish blue dorsally, shading to blue towards posterior edge and downwards, then becoming grayish with darker spots. Prothorax. Olive-green, covered in grey pruinosity. Synthorax. Olive-green, somewhat grayish on mesepisternum and towards coxae, and with very thin brownish line over metapleural suture. Green spots on dorsum between wings. Legs Dark brown, insides of femora of first pair pale yellow and of second and third pair with some yellow at base. Wings. Hyaline. Dark brown basal streak along subcosta in costal and subcostal space, extending to fifth antenodal crossvein in forewing and third antenodal crossvein in hindwing. Veins brown. Membranule pale. Anal loop 13–14 celled. Forewing triangle 6–8 celled, hindwing 5–6 celled. Crossveins forewing 19–28:29–19 and hindwing 20–21:19–21. Pterostigma pale brown, covering 4 cells in all wings. Abdomen. S1 green, somewhat more blue dorsally, S2 largely green, dorsally with a large brown mark divided into four parts. Anteriorly two almost square spots narrowly separated over dorsal carina and at posterior margin elongated, extending along elongated green MD spots, and two bow-tie shaped PD spots, connected and at posterior end bordered by bluish green. S3 constricted and dorsally blackish brown, with almost imperceptible paired MD and slightly larger PD spots, anterior half ventrally with large bluish spot, and posterior half ventrally with small blue mark at posterior margin, S4–6 very dark brown with almost imperceptible paired MD and PD spots, S4 ventrally with blue spot at anterior margin and smaller spot at posterior margin, S5–6 with only a blue spot at anteroventral margin, S7 blackish brown with almost imperceptible MD spots, S8–10 and ovipositor ( Fig. 6 A–B) blackish brown. Caudal appendages ( Fig. 6 A–B). Blackish brown. Cerci approximately as long as S9–10.

Variation in paratypes ( Figs. 1 B, 3D). Synthorax of one paratype female with some pruinosity towards venter. Anal loop 11–12 celled. All triangles 6–7 celled. 24–29 antenodal crossveins and 17–20 postnodal crossveins in forewing, 19–22 antenodal and 17–21 postnodal crossveins in hindwing.

Collected paratypes all relatively aged. Younger individuals ( Fig. 3 B–C) more brightly marked, with green thorax and wings not enfumed, abdominal markings in blue and green.

Measurements (mm). ♂ Hindwing 44–48; abdomen including appendages 52–54.

♀ Hindwing 47–50; abdomen excluding appendages 50–52.

Diagnosis. The appendages at a single glance separate the male of this species from all other Gynacantha species in Southeast Asia but not from G. khasiaca . From that species it can be separated by the lack of blackish or reddish-brown stripes over the dorsal carina and lateral sutures of the thorax and the color of the compound eyes ( Figs. 1 A, 2, 3A). In addition, there are structural differences. The auricles in ventral view are somewhat more slender in G. cattienensis and have 2–4 distinct teeth ( Fig. 5 F) and sometimes a smaller 5th. Fraser (1936) mentions rounded auricles with 5–6 teeth for G. khasiaca , and the lectotype of G. khasiaca has 7 ( Fig. 5 G). And although the appendages are rather similar in lateral view ( Fig. 5 D–E) and in general impression in dorsal view ( Fig. 5 A–C), the cerci do not smoothly curve back towards a slightly inward-directed apical spine in G. khasiaca as they do in G. cattienensis ( Fig. 5 A–B), but have a distinct small bulge just proximal of the less pronounced distal spine ( Fig. 5 C).

Like the male, the female of G. cattienensis can be separated from G. khasiaca by the absence of dark stripes on the thorax ( Figs. 1 B, 3B, D) and can be separated from all other species in Vietnam by the dark streaks at the wing bases ( Figs. 1 B, 3B–D), apart from the female of G. basiguttata Selys, 1882 . G. basiguttata has green and yellow compound eyes, not purple and blue. It also has longer and apically expanded cerci and is distinctly larger (HW 55 mm, abdomen without appendages 57 mm of female taken at same location).

Discussion. According to Fraser (1936), G. khasiaca has bright olive-green face, greenish eyes, and a bright grass-green thorax, with clearly defined reddish-brown stripes. In G. cattienensis the face is yellow, the compound eyes are blue, with purplish tones above ( Figs. 1 A, 2, 3A), and the olive-green thorax lacks dark bands over the sutures or dorsal carina ( Figs. 1 , 2 , 3 ). However, the original description by McLachlan (1896) is somewhat different from that of Fraser (1936). He describes G. khasiaca as having a yellowish face and does not mention the color of the compound eyes. He describes the thorax as “dark greenish above, dorsal crest black; sides somewhat more yellowish, with indications of two narrow black bands, one on the humeral suture, the other on the interalar suture.” (Italics added) The meaning of “indications” is a little puzzling. In photos of specimens identifiable as G. khasiaca from the same general geographic area as the Khasi Hills (i.e. the drainage of the Brahmaputra) the bands over the sutures are obvious ( Conniff 2014, Khan 2015). The holotype is no longer available, and D. E. Kimmins designated a lectotype, which is currently in the Natural History Museum in London ( Figs. 4 , 5 C, E, G). This lectotype has darkened as a result of conservation or age, but the dark line over the metapleural suture (presumably this is the suture that McLachlan refers to as “interalar”) is still very obvious and the stripe over the humeral suture somewhat less so ( Fig. 4 B). Clearly these stripes are typical of G. khasiaca . Possibly McLachlan, who also mentions a female specimen from Annam ( Vietnam), struck a balance in his description between more (Khasi Hills) and less ( Annam) marked specimens he considered to be G. khasiaca , but this is conjecture.

Although Fraser (1936) describes the compound eyes as greenish, photos of live individuals ( Conniff 2014, Khan 2015) indicate that this may be incorrect. These specimens have grey-blue compound eyes. G. cattienensis has darker blue eyes with a distinct purplish dorsal side ( Figs. 1 , 2 , 3 ), strikingly different from either the description by Fraser or the life photos of G. khasiaca .

Martin (1904) reported G. khasiaca from Tonkin, northern Vietnam. He also mentions Annam, but this may refer to the specimen that McLachlan reported, as Martin also mentions India when providing the geographic range known to him at the time of writing. He did not give additional information on specimens or locations, nor a description.

Martin (1909) provided a short description of G. khasiaca in his treatment of specimens in the collection of Baron Selys de Longchamps. He does not mention Tonkin therein, only the locations mentioned originally by McLachlan (1896). He describes the thorax as “brun avec deux larges bandes antéhumérales vertes, les côtés verdâtres ou jaunâtres,” which translates as: “brown with two large green antehumeral stripes, its sides greenish or yellowish.” The omission of the dark stripes on the thorax is striking. Possibly Martin based himself here on Tonkinese specimens known to him, although Selys had, according to Martin, also a male in his collection. If the description is correct, it cannot refer to true G. khasiaca . G. cattienensis does not have distinct green antehumeral stripes either ( Fig. 3 A, C), but the description of the flanks as greenish or yellowish and apparently without lateral stripes make it possible that Martin’s crude description refers in fact to G. cattienensis . His illustration of the appendages ( Martin 1909: Fig. 207) clearly shows the subapical bulge and less developed apical curvature of G. khasiaca , unlike any of the specimens of G. cattienensis , so at least this illustration is based on a true G. khasiaca , and thus likely from the specimen in collection Selys. It is possible that the specimens Martin mentions from Tonkin in fact refer to G. cattienensis , although examination of the specimens is required to ascertain this. The occurrence of true G. khasiaca in Vietnam must be considered doubtful.

McLachlan (1896) mentions a related taxon, G. nigripes Selys, 1883 , from Tibet. This enigmatic species is also mentioned and illustrated in Martin (1909) as a race of G. khasiaca . He refers to the very limited information given by Selys (1883) that mentions that G. nigripes has very pointed cerci and an epiproct almost as long and lacks dark bases to the wings. That last character distinguishes it from G. cattienensis .

Notes on behaviour. More than 20 males were seen flying simultaneously at noon on several occasions at sections of 2 streams flowing through nearly primary forest, named Da Bruot (N 11° 26' 21.318'' E 107° 25' 16.543’’, Fig. 7 ) and Da Ban (N 11° 26' 38.609'' E 107° 24' 19.155''). Both streams appear identical with slowflowing or in dry season stagnant shallow water, thick mud substrate, and an abundance of Schumannianthus dichotomus (Roxb.) Gagnep. Males and females were also observed flying at dusk at numerous locations along the road and just before complete dark sometimes swarming over rapids in the Dong Nai river, presumably only to feed, as no mating behaviour was observed. The species sometimes enters buildings after dusk, attracted by light. Although several other aeshnid species fly at dusk within the same forest and lodge garden where G. cattienensis occurs (for instance G. basiguttata , G. dohrni Krüger, 1899 , G. subinterrupta Rambur, 1842 , and Heliaeschna uninervulata Martin, 1909 ), these apparently do not fly over the rapids of the main river.

Figures

FIGURE 1. Close-up of head and thorax of G. cattienensis in lateral view in life. A. Holotype male, 6 February 2016; B. Paratype female, 29 January 2017.

FIGURE 2. Males of G. cattienensis. A. Adult in situ, January 2016; B. Aged adult in situ, 30 January 2017; C. Live adult in hand, January 2016; D. Live paratype in hand, 29 January 2017.

FIGURE 3. G. cattienensis. A. Male in situ, January 2016; B. Adult female in hand, January 2016; C. Adult female, detail of wing bases, January 2016; D. Aged paratype female in hand, 29 January 2017.

FIGURE 4. Lectotype of G. khasiaca. A. Lateral view of complete type; B. Detail of thorax; C. Dorsal view with labels. Photos courtesy of Dr. Ben Price, Natural History Museum in London.

FIGURE 5. Caudal appendages and auricles of G. cattienensis and G. khasiaca compared. A. G. cattienensis holotype male caudal appendages in dorsal view; B. G. cattienensis paratype male caudal appendages in dorsal view; C. G. khasiaca lectotype male caudal appendages in dorsal view; D. G. cattienensis holotype male caudal appendages in lateral view; E. G. khasiaca lectotype male caudal appendages in lateral view; F. G. cattienensis paratype male S 2 and auricles in ventral view; G. G. khasiaca lectotype male S 2 and auricles in ventral view. Photos C, E, G courtesy of Dr. Ben Price, Natural History Museum in London.

FIGURE 6. Abdomen tip of paratype female of G. cattienensis. A. S 9 – 10, ovipositor and cerci in lateral view; B. S 10 and cerci in dorsal view.

FIGURE 7. Da Bruot Stream in Cat Tien National Park, habitat of G. cattienensis.