Protosticta tubau, Dow, 2010

Dow, Rory A., 2010, Two new Platystictidae (Odonata: Zygoptera) from Sarawak, Malaysian Borneo, Zootaxa 2412, pp. 63-68 : 66-67

Protosticta tubau sp. nov.

( Figs. 8–12)

Material. Holotype: teneral ♂ (SAR09_10_PST1), Malaysia, Sarawak, Bintulu Division , PFZ, Tubau area, in disturbed forest ca 3 m away from stream in block E2K, N 3º 6.941’ E 113º 39.267’, ca 156 m, 16–VIII– 2009, leg. R. A. Dow. To be deposited in RMNH.

Etymology: Tubau, a noun in apposition. Named for the area of the type locality; no name is known for the specific location.

Description: Head ( Fig. 8): Labium pale cream except for end hooks of labial palps, which are brown. Labrum blue except for lower ca 1/4 along free margin, where shining black. Anteclypeus blue, postclypeus shining black. Mandible bases pale blue in upper half, brown below, genae black except narrowly beside mandible bases, where obscurely pale. Vertex and frons shining metallic greenish-black, occiput shining black. Vertex relatively narrow; ratio of width of compound eye to width of vertex measured at level of lateral ocelli ca 7/8. Lateral extremities of transverse occipital carina angulated and very prominent. A single long seta originating just above the transverse occipital carina directly behind each lateral ocellus. Ocelli whitish, distance between lateral ocelli significantly less than that between either lateral ocellus and median one. Antennae with scape and pedicel dirty white, top of pedicel brown, rest black.

Thorax: Prothorax with propleuron pale whitish, except at rear where obscurely marked with grey and brown. Pronotum with anterior lobe whitish, median lobe same, except at extreme rear, where very narrowly brown. Posterior lobe dark shining brown, hind margin simple but produced laterally into a long hanging, recurved process ( Fig. 9), reaching almost to the lower margin of the propleuron. Synthorax: Mesepisternum dark shining brown, with a pair of broad pale blue antehumeral stripes, tapering to rear and occupying ca 4/5 of the length ( Fig. 11). Antealar triangles pale blue. Mesepimeron largely bronzy black. Metepisternum with a broad pale blue stripe in upper part, extending to lower margin of spiracle, tapering towards antealar carina. Metepimeron pale bluish, obscurely brown around midlength below metepleural suture. Venter of synthorax pale. Legs: each with coxa and trochanter pale cream, femur also pale cream, with obscure grey markings, black above tibia. Tibia dark proximally, then pale greyish, darker on flexor surface. Tarsi brownish. Wings: 11 (left) to 12 (right) Px in Fw, 10 Px in Hw. Arculus slightly distal to Ax2. R 4 arising distal to subnodus, IR 3 joined to it by a short stalk. 1A entering wing margin near (left) or slightly proximal (right) to Px 2 in Fw, at Px2 (left) or 3 (right) in Hw. Pterostigma approximately square, deep, pale brown, rear side slightly angulated, covering slightly more than one underlying cell.

Abdomen: Largely pale brown, darkening to rear. S1 brown above, pale below. S2 with a pale basal annulus, laterally this extending towards, but not quite reaching, the posterior carina as a pale wedge. S3 with a narrow pale basal annulus, very narrowly interrupted along the dorsal midline, S4–7 similar, but basal annulus not interrupted. S8–9 largely pale blue above. S10 entirely brown, dorso-ventrally expanded, dorsum largely occupied by a dense tuft of setae of approximately the same length as the segment ( Fig. 10). Appendages ( Figs. 10, 12) largely dark brown and black. Cerci ca 5/2 times the length of S10, slender in basal half, expanding and dorso-ventrally flattened towards tips. A tuft of setae at tips of cerci. Paraprocts almost as long as cerci, robust in basal half, rounded at tips in dorsal ( Fig. 12) and ventral view, dorso-ventrally flattened and appearing sharp at tips in lateral view ( Fig. 11). Rounded section of paraproct hollow and spoonlike on dorsal surface ( Fig. 12). Genital ligula partly visible, with the terminal segment broad and the cleft between the terminal branches triangularly convex, and with many bristles on the shaft.

Measurements (mm): Abdomen without caudal appendages 30.5, cerci ca 1.25, Hw 18.

Diagnosis. Readily distinguished from all other members of the Platystictidae known from Sundaland by the tuft of long setae on the dorsum of abdominal segment 10.

Remarks. Based on the structure of the posterior pronotal lobe, the dimensions of the head, the colour patterns of synthorax and terminal abdominal segments, P. tubau belongs in a group of species typified by Drepanosticta dupophila Lieftinck and Protosticta feronia Lieftinck and also including D. paruatia van Tol from Palawan in the Philippines, as suggested by van Tol (2005: 175), as well as a number of undescribed species. P. tubau differs somewhat from the other species of the group in the form of its terminal appendages, although they follow a similar general ‘plan’; the tuft of long setae on the dorsum of S10 is a unique feature.

Although the type locality is unsuitable for plantation, it does not currently have any protected status and might be re-logged for its remaining timber in the future. It is threatened in the short-term by small-scale illegal logging activities.