Telosticta janeus, Dow & Orr, 2012

Dow, R. A. & Orr, A. G., 2012, Telosticta, A New Damselfly Genus From Borneo And Palawan (Odonata: Zygoptera: Platystictidae), Raffles Bulletin of Zoology 60 (2), pp. 361-397 : 394-395

Telosticta janeus , new species

( Figs. 16B, D, F , 17B, D , 18B, D , 19 )

Material examined. — Holotype: male (JvT 19977), Malaysia, Sabah, Danum Valley , 19 Mar.1987, coll. J. v. Tol, in RMNH.

Paratypes (all from Malaysia, Sabah): 4 males (JvT 19975–9), data as holotype, RMNH ; 3 males (JvT 19980–2), same area, brooklet at “West 5”, 160 m, 20 Mar.1987, coll. J. v. Tol, RMNH ; 4 males, Imbak Canyon, Ridge Trail, sub camp B, 2 Dec.2010, coll. CYC, in collection CYC; male, same area, “small river”, 3 Dec.2010, coll. CYC, in collection CYC.

Diagnosis. — Readily distinguished from all other known Telosticta species except T. belalongensis by the form of the superior appendages, with the terminal part flattened and folded over on its self. Separated from T. belalongensis by its shorter lateral processes of the posterior pronotal lobe; superior anal appendages without a well-developed dorsal projection, but with a dorsal crest near the end, and the shape of the spine and scoop of the inferior anal appendages.

Etymology. — janeus , a noun in apposition; a Latinised form of Jan, named for Jan van Tol.

Description of holotype male. — Head: Labium pale. Basal 4/5 of labrum blue, black along free margin. Anteclypeus

blue, postclypeus shining black. Mandible bases blue in corner by clypeus, black below, genae black. Vertex and frons bronzy black, occiput shining black. Ratio of width of compound eye to width of vertex measured at level of lateral ocelli ca 9/10. Transverse occipital carina with lateral extremities prominent. Ocelli whitish. Antenna with scape and top ca 1/4 of pedicel brown basal 3/4 of pedicel greyish pale, flagellum dark brown (missing on right).

Thorax: Prothorax, largely creamy white with blue patches dorsally on middle pronotal lobe, except to rear of propleuron and the rear part of middle pronotal lobe where black and dark brown with paler areas, and whole posterior pronotal lobe which is black, becoming brown towards tips of lateral pronotal processes, which are moderately long. ( Fig. 17B ). Synthorax: Mesepisternum bronzy black, with a pair of long pale blue antehumeral markings, tapering to rear and occupying ca 4/5 of the length ( Fig. 16B ). Antealar triangles mostly black, except at rear where pale. Mesepimeron mostly bronzy black. Metepisternum largely occupied by a pale band, spilling over onto the lower part of the mesepimeron, becoming blue towards wing bases, with a bronzy black wedge below, this extending from the wing bases to the metinfraepisternum. Metepimeron mostly pale, with a dark brown area below the metepleural suture centrally. Venter of synthorax pale. Legs: each with coxa and trochanter cream, femur dirty cream with a narrow dark stripe long the extensor surface, and obscure grey and dark markings elsewhere, black immediately above joint. Tibia similar but more extensive dark stripe on extensor surface and another on flexor surface. Tarsus dirty cream, black around joints, claws pale brown. Wings: 13 Px in Fw, 12 Px in Hw. Vein ab absent. R 4 arising distal to subnodus in Fw, very slightly distal to subnodus in Hw, IR 3 joined to it by a short stalk. Pterostigma approximately trapezoidal with costal side shorter than anal side, and proximal side shorter than distal side, dark brown with slightly paler border, covering slightly more than one underlying cell.

Abdomen: Largely brown, darkening to rear. S1 brown above and to rear laterally, white otherwise. S2 brown with a pale basal annulus (possibly pale blue in life), narrowly interrupted dorsally, laterally extending to the posterior carina as a pale wedge. S3–7 brown with a narrow pale basal annulus interrupted dorsally and extended laterally near lower margin of tergite for a distance, each segment becoming darker apically. S8–10 black with a pair of pale blue dorsal-lateral markings on S8, very narrowly separated dorsally, and a basal dorsal marking on S9 ( Fig. 16D, F ). Appendages ( Figs. 17D , 18B, D ) largely dark brown with obscure paler areas interiorly and dorsally. Superior appendage ca 2.5 times the length of S10, with robust but blunt interior projection at ca 1/3 length directed inwards. Dorsal projection a small rounded swelling only narrowly separated from the basal projection, but there is a thin subapical ca semicircular crest, prominent in lateral view. Expanded in distal 1/2 but folded under itself to nearly form an open-mouthed tube with the outer corner produced in a distinctive manner ( Fig. 18B ). Inferior appendage almost as long as superior, stem robust and scoop strongly expanded then tapering to tip, up- and out-turned almost immediately, spine directed inwards, slightly upwards and to rear.

Measurements (mm): Abdomen without anal appendages 33, superior appendage ca 1.2, Hw 20.5.

Female. — Unknown

Variation in paratypes. — There are small variations in the markings of the head and thorax in the paratypes; in particular the extent of the intrusion of the pale stripe on the metepisternum onto the mesepimeron is greater than in the holotype. In one of the Imbak Canyon specimens the antehumeral stripes are shorter, ca 2/3 of the length of the metepisternum. In one paratype the lateral extremities of the transverse carina are much less prominent. There is some variation in the length of the lateral processes of the posterior pronotal lobe, in one case they are longer than in the holotype, in another they are shorter and poorly developed. The colour of the pterostigma varies from deep chestnut brown to almost black and the paler border is often only partially present and varies from just paler than the central part to considerably paler; in one paratype no border is apparent. The S 8 dorsal markings are sometimes fused and sometimes more widely separated than in the holotype, and the dorsal part appears to fade somewhat with increasing maturity. The extent of the S9 marking varies considerably, and it is sometimes divided into two. The Imbak Canyon specimens are slightly larger on average than those from the Danum Valley, and have S1 paler dorsally and slightly more extensive pale colouration along the lower margins of S3–7 .

Measurements (mm): Abdomen without appendages 31–35, Hw 19.5–22.5. Wings with 11–13 Px in Fw, 10–12 in Hw.

Biological notes. — Little has been recorded on the biology of this species, but all specimens have been collected at small streams in mixed dipterocarp forest in hilly or mountainous terrain.

Distribution. — Known only from the Danum Valley and Imbak Canyon in Sabah ( Fig. 19 ).

Figures

Fig. 16. Markings of T. belalongensis and T. janeus. T. belalongensis holotype: A, antehumeral markings; C, terminal abdominal segments, dorsal view; E, terminal abdominal segments, lateral view. T. janeus holotype: B, antehumeral markings; D, terminal abdominal segments, dorsal view; F, terminal abdominal segments, lateral view.

Fig. 17. T. belalongensis and T. janeus. T. belalongensis holotype: A, posterior pronotal lobe, lateral; C, right inferior anal appendage, ventral view. T. janeus holotype: B, posterior pronotal lobe, lateral; D, right inferior anal appendage, ventral view.

Fig. 18. T. belalongensis and T. janeus. T. belalongensis holotype:A, anal appendages dorsal; C, anal appendages lateral. T. janeus holotype: B, anal appendages dorsal; D, anal appendages lateral.

Fig. 19. Distribution of T. bidayuh (cross), T. janeus (open square), T. feronia (black square), and T. longigaster (circle).