Amphicnemis bebar Dow, Choong & Ng, 2010, sp. nov.
Creators: name: Dow, Rory A.
name: Choong, Chee Yen
name: Ng, Yong Foo
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Coenagrionidae
Amphicnemis
Amphicnemis bebar

description: Amphicnemis bebar sp. nov.
(Figs. 3, 7, 9, 15, 18, 22)
Type material. Holotype: ɗ (PAH09_COE20), Malaysia, Pahang, low pH swamp upstream on Sg Bebar, 23 ix 2009, leg. R.A. Dow, RMNH. Paratypes: 10 ɗɗ (PAH09_COE10–19), 5 ΨΨ (PAH09_COE1–5), location as holotype, 22 ix 2009; 7 ɗɗ (PAH09_COE21–27), 2 ΨΨ (PAH09_COE28–29), data as holotype; 5 ɗɗ, 3 ΨΨ, location as holotype, 23 ix 2009, leg. C.Y. Choong. Paratypes in RMNH, UKM, coll. Choong and coll. Dow.
Etymology: Bebar, a noun in apposition. Named for the type locality, Sg. Bebar.
Description of holotype male. Head: Labium pale. Mandible bases black except for a whitish band along upper and lower margins, genae pale, labrum shining black except for narrowly along free margin, where pale. Anteclypeus shining black except for a whitish mark centrally just above labrum and a pair of lateral marks of the same colour. Postclypeus very dark brown. Vertical face of frons shining black, with a pair of small brown marks at either end, horizontal face and vertex dark metallic green, ocelli whitish. Antennae with a faint brown patch on base, scape black with pale ring at top, pedicel and flagellum dark brown. Occiput black.
Thorax: Prothorax with pronotum almost entirely very dark metallic green, except for small obscurely pale areas on anterior lobe. Propleuron black above, cream below. Posterior pronotal lobe with a distinct peak centrally on the free margin (Fig. 7). Synthorax with mesepisternum and mesepimeron dark metallic green, as is most of the mesinfraepisternum. Metallic green colouration extending onto upper part of metepisternum, and to metepleural suture near wing bases, cream below. Metepimeron brown near wing bases, otherwise cream as are the metinfraepisternum and venter of synthorax. Legs cream coloured, femurs with a black stripe along extensor surface and a small black area immediately above tibia. Tibia with small black marks below femur, more extensive on anterior legs where extended over ca 1/2 length, and above tarsi. Spines on femur and tibia dark brown. Tarsi cream with dark brown spines and articulations, tarsal claws paler with darker tips and a tiny rudimentary tooth. Wings with 12 Px in Fw and 11 Px in Hw. Arculus slightly distal to Ax2. 1A arising distal of Ac, IR3 and R4 arising distal of subnodus. Pt (Fig. 9) with costal side shorter than anal, dark brown with pale border, covering slightly more than one underlying cell, slightly smaller in Hw than Fw.
Abdomen: S1 dark bronzy brown above, paler to sides except apically, where brown. S2 bronzy brown dorsally, darker to rear, with a narrow, dorsally interrupted, pale basal annulus. S3–7 brown dorsally, becoming darker on successive segments, paler laterally (again S7 darker), this extended dorsally as a narrow, interrupted, basal annulus, becoming less clear on successive segments, and with a faint subapical stripe, orientated from dorsum diagonally rearward. S8–9 dark brown. S10 dark above, paler to sides, cream at rear dorsally and laterally. Genital valves as Fig. 15. Cerci (Figs. 18, 22) with upper branch long, with a shallow triangular projection, directed inward and ventrally, before mid length, strongly down curved towards the tip, which is expanded ventrally. Paraprocts with hairs (not shown in the Figs.) on dorsal and ventral surfaces. Epiproct prominent.
Measurements (mm): Abdomen without appendages 30.5, upper branch cercus slightly more than 1, Hw 18.
Description of female paratype (PAH09_COE1). As male except as noted. Head: More extensive pale markings than male. Labrum with a broad pale band along free margin, narrowly extended towards base centrally. Mandible bases with a pale border. Vertical face of frons black with pair of transverse pale stripes nearly meeting centrally. Pale stripes along antennae bases and a pale lateral/rear stripe on pedicel.
Thorax: Prothorax mottled pale blue and pale red, anterior margin of anterior pronotal lobe black, posterior lobe produced into a vertical and slightly forwards slanted horn as shown in Fig. 3, the tip of the horn black. Synthorax largely pale blue-green above, becoming cream on lower part of metepisternum and metepimeron, venter cream. Legs similar to male but dark stripes brown, that on anterior tibia not reaching half length. Wings with 13 Px in Fw, 12–13 in Hw. R4 arising at subnodus on left Hw.
Abdomen: Similar to male but with pale basal annulus on S2–7 brighter and better defined, and a poorly defined pale dorsal lateral sub apical marking on S2. S9 brown laterally, dark brown above, with a pale bluish subapical lateral spot. S10 pale bluish above except for a small indistinct central brown spot, greyish brown to sides. Cerci whitish, ca same length as S10. Paraprocts dirty white, rounded and featureless. Ovipositor mostly pale, except for a brown basal lateral streak and stylus, which is brown except at tip.
Measurements (mm): Abdomen without appendages or ovipositor 32.5, Hw 19.5.
Variation in paratypes. Males: The peak on the posterior pronotal lobe is produced into a distinct vertical horn in some individuals; this is always distinctly shorter than the horizontal part of the lobe anterior to it. There is some variation in the shape of the Pt, and in a few individuals it is the same size in Fw and Hw, in others the shape is different in the Hw, with the costal side shorter relative to the anal side than in the Fw. R4 typically arises distal to the subnodus, but at the subnodus in one specimen. The holotype appears to be a very mature individual. Mature males are mostly very similar but the pale markings on the vertical face of the frons and the antennae bases are brighter on some, more faded in others. Immature and teneral individuals have these markings brighter, and larger; those on the frons are narrow, distinct but widely separated transverse stripes. The pale markings on the mandible bases are variable, but much more extensive on immature and teneral specimens. The pale mark on the anterior pronotal lobe is reddish in teneral specimens, and the dark markings on the legs are less distinct and brown rather than black. The pale border of the Pt is broader in tenerals, and a small apical lateral red patch is present on S3–7.
Females: The transverse stripes on the vertical face of the frons are variable; in one immature female they are short and widely separated, although typically they are long and narrowly separated on teneral and immature females. The horn on the posterior lobe of the pronotum is shorter in one specimen than that described and illustrated in Fig. 3. The female described is not quite fully mature, in two fully mature females there is no red on the prothorax. Teneral and immature females have almost the entire thorax red, with just the anterior part of the anterior pronotal lobe and the tip of the horn on the posterior lobe black; the legs are also largely red.
Measurements (mm): Males: abdomen without cerci 32–33.5, Hw 18–19.5. Females: abdomen without cerci or ovipositor 31.5–34.25, Hw 19.25–21.
Diagnosis. A typical Amphicnemis, small and lightly built in both sexes, with males dark metallic green and bronzy black above, paler below and females with a red immature form and a bluish green mature form. A. bebar is separated from all other species of Amphicnemis known from Peninsular Malaysia and Singapore by the characters given in the keys. A. bebar is most similar to A. billitonis Lieftinck, 1940, a species known only from the Indonesian island of Belitung (formerly Billiton) (Lieftinck 1954), situated between Sumatra and Borneo. The male of A. bebar differs from A. billitonis in the details of the upper branch of the cercus; in particular in A. bebar the projection is directed inwards and ventrally whereas in A. billitonis it is directed inwards and dorsally, so that it is visible in lateral view. It also differs in having the raised central part of the posterior pronotal lobe, although variable, always considerably shorter than in A. billitonis. The female A. bebar has a considerably shorter horn (see Lieftinck 1940, Pl. 15) on the posterior pronotal lobe than the female A. billitonis.
Remark. It is possible that in periods of lower sea levels a cline might have existed between A. bebar and A. billitonis. However any such hypothetical cline has long since been obliterated by the South China Sea; A. bebar is best considered as a separate species.
description: Published as part of Dow, Rory A., Choong, Chee Yen & Ng, Yong Foo, 2010, A review of the genus Amphicnemis in Peninsular Malaysia and Singapore, with descriptions of two new species (Odonata: Zygoptera: Coenagrionidae), pp. 45-55 in Zootaxa 2605 on pages 47-49, DOI: 10.5281/zenodo.197652