Euphaea cyanopogon, Hämäläinen & Kosterin & Kompier, 2019

Hämäläinen, Matti, Kosterin, Oleg E. & Kompier, Tom, 2019, Euphaea cyanopogon sp. nov. from the Cardamom ecoregion in Cambodia and Vietnam (Odonata: Euphaeidae), Zootaxa 4555 (1) : -

Euphaea cyanopogon sp. nov.

( Figs 1–21 , 25–26 , 29 , 31 )

Euphaea ochracea , nec (Selys, 1859)— Bùi 2008, p. 6; records from three localities in Phú Quỗc Island in May and December 2007, including three colour photographs of male and female.

Euphaea sp.— Kosterin 2010, p. 59-60, Fig. 40 below; report of a female collected in the Kbal Chhay Waterfall area in Cambodia in April 2010.

Euphaea ochracea , nec (Selys, 1859)— Do et al. 2011, p. 55, included in species list of known Odonata from Phú Quỗc Island. No new material.

Euphaea ochracea , nec (Selys, 1859)— Kosterin et al. 2012, p. 152-153, Fig. 2 ; record of male specimens collected in the Kbal Chhay Waterfall area in Cambodia in July 2007.

Euphaea ochracea , nec (Selys, 1859)— Kosterin 2016, p. 24; morphological and colour differences of the Kbal Chhay specimens of ‘ E. ochracea ’ from those from Mondulkiri province in Cambodia. (The Mondulkiri specimens have later been described as Euphaea sanguinea Kompier & Hayashi in Phan et al., 2018 ).

Euphaea pahyapi , nec ( Hämäläinen, 1985)— Phan et al. 2018, p. 176–178, Figs. 18f, 19 , 22 ; reidentification of specimens from Phú Quỗc Island in Vietnam and Kbal Chhay Waterfall in Cambodia; records of new specimens collected by Tom Kompier from Phú Quỗc in 2016, illustrations of male habitus, thorax, wings, appendages, vesicle, map of distribution in Vietnam.

Holotype: ♂, Cambodia, Preah Sihanouk province , just below Kbal Chhay Waterfall, 10.6744-6750° N 103.6086- 6097° E, 40-48 m a.s.l., 10 iii 2017, Oleg Kosterin leg. Deposited at Naturalis Biodiversity Center, Leiden, the Netherlands ( RMNH).

Paratypes: 11 ♂♂, 2 ♀♀ (from these 2 ♂♂, 1 ♀ preserved in alcohol), the same locality, date and collector as holotype ; 3 ♂♂, 1 ♀ (1♂, 1♀ in alcohol), the same locality as holotype, 9 xi 2018, Oleg Kosterin leg. (deposited at RMNH and in collections of Matti Hämäläinen and Oleg Kosterin) ; 1 ♂, the same locality, 10.675° N, 103.608° E), 16 vii 2007, François Mey leg. (In collection of François Mey) ; 1 ♀, Cambodia, Preah Sihanouk Province, Kbal Chhay Waterfall environs, a left tributary of the main Prek Toeuk Sap River in its lowermost reaches, 10.6773° N 103.6088° E, 48–55 m a.s.l., 19 iv 2010, Oleg Kosterin leg. (In collection of Matti Hämäläinen) ; 1 ♂, 1 ♀, the same locality,10.6751–6768° N 103.6081–6086° E, 6 iii 2017 (at RMNH) ; 5 ♂♂, 1 ♀, Cambodia, Preah Sihanouk Province, the Prek Toeuk Sap River 1–15 km downstream of Kbal Chhay Waterfall , 10.6675–6703° N, 103.6183– 6227° E, 11-16 m a.s.l., 9 xi 2018, Oleg Kosterin leg. (in collection of Oleg Kosterin) ; 1 ♂, Vietnam, Kiên Giang province, the northern part of Phú Qu ỗc Island, at the road DT973, 10.368° N 103.995° E, 30 xii 2015, Tom Kompier leg. ; 2 ♂♂, the same place and collector, 14 iv 2016. (In collection of Tom Kompier).

Additional specimens and field observations.— Records by François Mey from Kbal Chhay Waterfall in Cambodia: up to 6 individuals of both sexes observed on July 2011.— Records by Tom Kompier from the northern part of Phú Qu ỗc Island at the road DT973, 10.368° N 103.995° E: about 10 ♂♂ observed and photographed on 30 xii 2015 , 2 ♂♂ observed on 12 iv 2016, 4 ♂♂ observed on 19 viii 2016 and 2 ♂♂ observed on 20 viii 2016.— Records by Tom Kompier from the central part of Phú Qu ỗc Island, just south of Ho Duong Dong, 10.251° N 104.029° E.: 5 ♂♂ observed on 1 i 2016 , 3 ♂♂ on 2 i 2016 and 1 ♂ on 19 iv 2016.

Etymology. The specific epithet, a noun in apposition, is a composite of Latinised forms of two Greek words ΚΥάvεos: dark blue and πώγωv: beard, together meaning ‘blue beard’, referring to the coloration of the lower face in males of the new species.

Description of holotype ( Figs 3 , 5–10 , 25–26 , 29 ). Head ( Figs 5–6 ): Labium dark brown with pruinosed middle lobe and greyish base, bases of lateral lobes greyish. Base of mandible generally dull bluish, with distinct, very dark brown oval spot in anteriodorsal corner. Labrum very dark brown with two large yellow triangular spots with indistinct brown margins; occupying in total slightly more than half of its area. Anteclypeus glossy dark brown. Genae sky blue in upper part and brown in lower part; border between these colours indistinct while upper border between blue and black distinct and jagged, with two blunt projections of blue. Postclypeus, frons and occiput matt black. Antenna very dark brown, pedicel top brown. Long setae on anteclypeus, antefrons and in front of lateral ocelli.

Prothorax matt black; posterior lobe smooth, short and directed nearly upright; paired smooth swellings of median lobe with long setae.

Synthorax matt black with yellow marking as follows: traces of tiny antealar dots, a narrow stripe above interpleural suture ventrally curving towards mesinfraepisternum, two dorsally broadening stripes above and below metapleural suture, that on metepisternum narrowing, curving and continuing below spiracle; metinfraepisternum brown with a yellow stripe at anterior margin; venter black with two pairs of indistinct yellowish marks close to each other. Legs black.

Wings translucent ( Fig. 7 ), fore wing (FW) evenly and very slightly tinted amber-brown, hind wing (HW) with a slightly stronger smoky tint gradually becoming stronger to distal and posterior areas; zone between subcosta and radius anterior darkened. Pterostigma blackish, covering 10.5/11.5 (left/right) underlying cells in FW and 11/9.5 ones in HW; adjacent subcostal cells not darkened. Wings similar in shape, expanding to ca 2/3 of distance to node and then more or less uniformly broad to pterostigmata; HW ca 0.93 as long as FW and of the same breadth; FW ca 4.25 and HW ca 4.15 times longer than broad at the broadest point. FW with 30 antenodals and 31 postnodals; HW with 24 antenodals and 28/26 postnodals. Discoidal cell with one crossvein in all wings. Three cubito-anal crossveins in left FW, two in the other wings. Origin of R 3 at half to one cell distal to subnodus.

Abdomen black, sides of S1 with yellow spots. Lower margins of tergite 3 with dense long setae, no conspicuous setae elsewhere. S10 with a raised, acute hind margin, dorsal prominence distinctly grooved ( Figs. 9– 10 , 25–26 ). Superior appendages gently tapering in dorsal view, narrowing also in lateral view, with an elongate, proximally rounded ventral lobe; short inferior appendages visible in lateral view.

Secondary genitalia of a typical structure for the genus ( Figs 8 , 29 ). Hamuli in ventral view very broad, scarcely tapering to apices, with apices abruptly down-turned. Vesicle evenly rounded, not grooved. Penis shaft without setae.

Measurements (in mm). Abdomen without appendages 33; HW 31; total length 46.5, pterostigma 3.5.

Variation in paratype males . The holotype is the darkest male specimen in the type series. Other males do not show the slight brownish suffusion in the hind wings but have both wings evenly dull ochreous tinted; with a variable extent of suffusion of the subcostal zone. With three exceptions (similar to the holotype), male paratypes have the genae sky-blue throughout, not darkened in lower part. In some paratypes, the anterolateral border of the frons adjacent to the gena is narrowly blue. The colour pattern of the labrum is variable: dark brown to black with a pair of either dull yellowish, yellowish blue or distinctly blue spots of variable size and form. In one paratype (of the same series as the holotype) the dull yellow spots are small, less than half of the size of those in the holotype, but based on the extent of pale stripes on thorax and on its rather shrunken condition, this specimen is quite young. The variability in the face colour pattern is depicted in Figs 11–13 , which shows the face of three living individuals (all not necessarily showing the paratype specimens) from Cambodia and Phú Qu ỗc .

Many paratypes have also paler brown portions on the prothorax. All but one of the paratypes have a more extensive yellow colour pattern on the synthorax than in the holotype. All but one paratypes have a narrow antehumeral stripe above mesopleural suture (absent in the holotype) and three also have a dorsal stripe below middorsal carina (vestigially present in some others); the other stripes are more developed than in the holotype (similar to Fig. 1 ); in some specimens the stripes on the metepisternum and metepimeron form distinct loops close to the wing border (as in Fig. 2 ). In the Cambodian series the number of antenodals varies 24–31 in FW and 20–25 in HW, that of postnodals varies 24–33 in FW and 21–29 in HW. The discoidal cell has one crossvein in all paratypes and either two (most frequently) or three cubito-anal crossveins in both wings.

In most paratypes, S2 has one or two narrow yellow lateral streaks and an additional roundish dot laterally at the hind margin; some have a small apical dot laterally on S3. The ground colour of S1–3 is somewhat lighter reddish-black. Measurements: abdomen without appendages 31.5–34.5 mm, HW 28–30.5 mm, total length 44–47 mm.

Female ( Figs 4 , 14–21 , 31 ). Head ( Figs 14–15 ). Labium pale brown, middle lobe darkened in one specimen, apical hooks black or dark brown. Base of mandibles pale ochre with a small oval black spot at upper part of anterior margin. Labrum pale ochre with glossy black margins and black oval central spot adjacent to upper margin. Mandible hooks and anteclypeus glossy brown-black; anteclypeus with an indistinct pale bipartite spot (two merged triangles). Genae pale ochre; border of this colour straight and distinct, extending to the anteriolateral edges of frons. In one specimen, the anteriolateral edges of frons are distinctly more broadly yellowish than in Fig. 14 , but the pale patches do not meet centrally. Rest of head matt black. Pale brownish spots between lateral ocelli and bases of antennae rather indistinct in most specimens, but very distinct in the specimen with most extensive pale markings. Antenna black, pedicel tip brownish. Long setae on anteclypeus, antefrons, and in front of lateral ocelli.

Prothorax ( Figs 16–18 , 31 ). Anterior lobe black, in two specimens its marginal ridge has a pair of brown areas; median lobe black with a pair of large pear-shaped yellow spots on convex swellings; posterior lobe black with yellow sides; one specimen with a small broadly triangular yellow spot at its centre; another specimen with the upper margin of posterior lobe narrowly yellow; propleuron yellow with black anterior, dorsal and posterior margins. Posterior lobe at first protrudes behind at low angle but its margin rises considerably; its outline in dorsal and subdorsal views being a rounded blunt angle. Paired swellings of median lobe with long setae.

Synthorax black with yellow stripes ( Fig. 19 ), in older specimens stripes less distinct. Mesepisternum black with narrow antehumeral and humeral stripes; mesepimeron with more yellow than black, with broad yellow stripes narrowing dorsally and fusing into a complete loop enclosing elongate black area; mesinfraepisternum yellow; metathorax largely yellow with a distinct black darkening above spiracle, with narrow black stripes along alar ridges and in dorsal parts of interpleural and metathoracic sutures. Coxae light brownish, legs brownish-black.

Wings ( Figs 4 , 20 ) translucent with a slight yellowish tint, venation dark. Pterostigma dark brown, covering 7– 10 underlying cells in FW and 7–8 cells in HW. FW with 22–27 antenodals and 25–29 postnodals; HW with 19–22 antenodals and 22–26 postnodals. Discoidal cell usually with one crossvein, in one specimen crossvein is present in only one HW; two cubito-anal crossveins. Origin of R 3 somewhat variable, usually one and half cell distal to subnodus.

Abdomen black with yellow markings: S1 yellow with a dorsal black spot; S2–6 with lateral yellow stripes; S7–10 with small lateral spots at distal part, in older specimens these yellow spots are missing and the stripe on S6 is restricted to a small apical spot. Ovipositor yellowish with brown first valves. Cerci black, narrowly conical and pointed ( Fig. 21 ).

Measurements (in mm). Abdomen without appendages 29.5–31; HW 28–30; total length 38–41.

Differential diagnosis. With its evenly brownish-amber tinted wings the male of Euphaea cyanopogon sp. nov. ( Figs 1–2 ) superficially resembles that of E. pahyapi ( Figs 22–23 ) from southern Thailand. However, these two species have clear structural differences. Males of cyanopogon have proportionally slightly longer and narrower wings, the fore wings being ca 4.1–4.25 times as long as broad at the broadest point (in pahyapi ca 3.9– 4.0) and hind wings correspondingly ca 3.9–4.1 (in pahyapi ca 3.6–3.8). The overall wing reticulation is denser in cyanopogon males than in pahyapi males. In cyanopogon males there are 24–31 antenodals in fore wings (in pahyapi correspondingly 20–25) and 20–25 in the hind wings (in pahyapi 16–20). (The number of postnodals is largely overlapping: in cyanopogon 24–33 in fore wings and 21–29 in hind wings; in pahyapi the corresponding numbers are 23–28 and 20–26.) The discoidal cell has a crossvein in all available cyanopogon specimens, but in pahyapi it is either entire or with one crossvein, both alternatives being often present in the same specimen.

The shape of S10 and the anal appendages differ to some extent. In cyanopogon ( Figs 9–10 , 25–26 ) the dorsal prominence in the apical part of S10 rises more abruptly than in pahyapi ( Figs 27–28 ). The vesicle is more rounded in cyanopogon ( Fig. 29 ) without the distinct lateral extensions present in pahyapi ( Fig. 30 ). In both species, the vesicle lacks distinct grooves.

A conspicuous feature in cyanopogon males is the mostly pale labrum and bright sky-blue genae, with a jagged colour border, contrasting with the black of the remainder of the head giving it a peculiar masked appearance ( Figs 11–13 ). In pahyapi males, the face is either almost uniformly dark brown or has pale (yellowish or possibly dirty bluish in life) markings ( Fig. 36 ); for details see below.

The amber-brown tint of the wings of cyanopogon males is on average slightly deeper than in pahyapi , and the subcostal zone is more or less darkened, although this character is not reliably diagnostic.

Euphaea cyanopogon males can be readily separated from E. ochracea (with which it was earlier confused) and E. sanguinea by the structure of the vesicle. In cyanopogon (as well as in pahyapi ) the surface of the vesicle is smooth, whereas in ochracea and sanguinea it is coarsely grooved. Moreover, the latter two species have a strong orange pigmentation on the basal half of wings, gradually decreasing towards the apices (see, for instance, Fig. 17a, f in Phan et al. 2018).

The female of E. pahyapi , known from numerous specimens collected in the type locality in Krabi at many occasions in 1982–2006 (available in the collections of Matti Hämäläinen and the late Amnuay Pinratana), has not been ‘formally’ described, but it has been illustrated with a colour photo by Hämäläinen & Pinratana (1999: 156; presented also here, see Fig. 24 ). Further illustrations are presented in this paper. In pahyapi ( Fig. 32 ), the posterior lobe of prothorax has slightly convex lateral shoulders forming a somewhat undulating outline (similar to E. masoni female). In cyanopogon the posterior lobe is rather straight at the sides ( Figs 16–18 , 31 ), forming a blunt round angle without distinct lateral ‘shoulders’. The colour pattern of the face is also different; unlike cyanopogon ( Fig. 14 ), in pahyapi the anterior surface of the frons has a complete, broad yellow band ( Fig. 33 ), and the pale dots between the base of antennae and lateral ocelli are larger in size. As in males, there is a clear difference in the density of the overall reticulation of the wings, that of cyanopogon being denser than in pahyapi . This is shown also in the number of antenodals and postnodals. Their number in six randomly selected pahyapi females from the type locality are: fore wing: 19–23 antenodals and 19–25 postnodals; hind wing: 15–19 antenodals and 18–23 postnodals.

Notes on ecology. In Cambodia, E. cyanopogon males perched on flat sandstone rocks close to running water in the vicinity of Khal Chhay Waterfall, or perched, as did females, on tips of dry branches of nearby trees at 1–2 m above the ground. Teneral specimens were observed in November 2018. Also at that time these damselflies were found at the Prek Toeuk Sap River 1–1.5 km downstream of the waterfall, where they were seemingly absent in May 2013 and March 2017. In Phú Quỗc Island the habitats were slightly different: small half-open streams: in central Phú Quỗc rocky streams located in forest that dried out seasonally; in northern Phú Quỗc just outside primary forest, sandy bottomed, shallow, with bushes at banks. There they tended to perch at 2–3 m over the water. Apparently, the flight season extends throughout the year; it has been recorded in March, April, May, July, and December. (However, not observed at the type locality in May 2013)

Distribution. Euphaea cyanopogon is known only from the Kampongsaom Peninsula in Cambodia and from Phú Quỗc Island in Vietnam. The Cambodian locality, Kbal Chhay Waterfall, is situated 11 km NE from the centre of Sihanoukville. The distance of the Cambodian and Vietnamese localities is only some 50–60 km, Phú Quỗc Island being separated from the Kampongsaom Peninsula by three straits, which are only 0.4, 1.4 and 4.3 km wide at their narrowest points. The species can thus be expected to inhabit (or having earlier inhabited) other localities in Kampongsaom Peninsula, including the smaller Ream Peninsula and two small Cambodian islands Thmei and Sês adjacent to the main peninsula. However, the second author did not find any Euphaea species during his five visits to the Ream Peninsula. A similar distribution (the Kampongsaom Peninsula (more precisely its Ream Peninsula) and Phú Quỗc Island) is found in the recently described Amphicnemis valentini Kosterin & Kompier, 2018 ( Kosterin & Kompier 2018).

Figures

FIGURE 33. Female of Euphaea pahyapi, anterior view of head. Illustration by A.G. Orr.

FIGURES 1–2. Males of Euphaea cyanopogon sp. nov. photographed in nature. (1) male from the type locality in Cambodia (Photo by Oleg Kosterin); (2) male from Phú Quỗc Island in Vietnam (photo by Tom Kompier).

FIGURES 3–4. Habitus of Euphaea cyanopogon sp. nov. (3) holotype male; (4) paratype female. Photos by Oleg Kosterin.

FIGURES 5–10. Male holotype of Euphaea cyanopogon sp. nov. (5) head, anterior view; (6) head, dorsal view; (7) wings; (8) genitalia, ventral view; (9) tip of abdomen with appendages, dorsal view; (10) tip of abdomen with appendages, lateral view. Photos by Oleg Kosterin.

FIGURES 11–13. Variation in the colour pattern of face in males of Euphaea cyanopogon sp. nov. (11) male from the type locality in Cambodia; (12) male from from Phú Quỗc Island in Vietnam; (13) from Phú Quỗc Island in Vietnam. Photos by Oleg Kosterin (11) and Tom Kompier (12–13).

FIGURES 14–21. Female paratype of Euphaea cyanopogon sp. nov. (14) head, anterior view; (15) head, dorsal view; (16) prothorax, dorsal view; (17) prothorax, oblique dorsal view; (18) prothorax, lateral view; (19) head (dorsal view) and thorax (lateral view); (20) wing tips; (21) tip of abdomen. Photos by Oleg Kosterin.

FIGURES 25–28. Comparison of the tip of abdomen and anal appendages (lateral and dorsal views) of male of Euphaea cyanopogon sp. nov. (25–26) and E. pahyapi (27–28). Illustrations by A.G. Orr.

FIGURES 29–30. Comparison of the genitalia (ventral view) of male of Euphaea cyanopogon sp. nov. (29) and E. pahyapi (30). Illustrations by A.G. Orr.

FIGURES 31–32. Comparison of the shape of posterior lobe of prothorax (oblique dorsal view) of female of Euphaea cyanopogon sp. nov. (31) and E. pahyapi (32). Illustrations by A.G. Orr.

FIGURES 22–24. Euphaea pahyapi, individuals photographed in nature at the type locality (Khao Phanom Bencha, Krabi province) in Thailand. (22–23) male; (24) female. Photos by Matti Hämäläinen.

FIGURES 34–36. Holotype male of Euphaea khaochongensis. (34) habitus; (35) tips of wings; (36) anterior view of head. Photos by Takuya Kiyoshi.