Rhipidolestes chaoi, Wilson, 2004

K. D. P. Wilson, 2004, New Odonata from South-China, Odonatologica 33 (4), pp. 423-432 : 427-428

RHIPIDOLESTES CHAOI SP. NOV.

Figures 9-14

Material. — Holotype ♂: Mangshan (nearBabaoshan), Shikengkong,S Hunan, China, 26-VI-2000, K.D.P. Wilson leg. - Paratype: 1 ♂, ditto, 26-V-2002, coll. K.D.P. Wilson. Holotype will be deposited at Tai Lung Experimental Station , Agriculture , Fisheries and Conservation Department , Lin Tong Mei , Sheung Shui, Hong Kong SAR, China.

Etymology. — Named in honour of the late Chao Hsiu-fu.

Description. — Medium-sized Rhipidolestes with ochreous face. Males with tiny conical projection on dorsum of ninth abdominal segment, inferior appendage with small

upward and minute outward, sharply pointed projections and penile organ with short, simply­ -shaped, broad lobes.

MALE. — Labium dark brown. Labrum, postclypeus, face and antennae chrome yellow. Anteclypeus reddish-yellow. Top of head above antennae matt blackish-brown with pale mid-brownish areas between antennae, surrounding the ocelli anteriorly and laterally and rear of head laterally ( Fig. 9 ). The occiput is blackish-brown. Prothorax matt-black with a pair of broad pale yellow dorso-lateral stripes. Dorsum of synthorax black with broad, yel­ low antehumeral stripes, which fall short ofthe posterior margin below the wings, typical of the genus. Small pale spot below wings. Sides of thorax black with broad ochreous yellow metepistemal stripe covering the spiracle. Metaposternum pale yellow. Metepimeron mainly black with small area adjacent to metaposternum and dorsal comer below hindwings pale yellow. Coxae mainly pale with smoky­ -black central areas. Legs pale ferruginous. Wings have medium venation density with mid-brown pterostigma subtending three segments ( Fig. 14 ). Extreme tips beyond pterostigma smoky-brown. Abdomen dark brown. Base of ninth segment with tiny, vestigial projection with single, blunt point. Caudal appendages blackish brown. Superior appendages very stout distal half with prominent, inwardly pointing, basal projection, minute outward pointing projection towards tip and narrow finger-like projection at tip ( Figs 12-13 ). Inferior appendages short, squarish, peg-like with dorsal, finely pointed projection and short, ventral projection. Penile organ with short, stout, squarish lobes ( Figs 10-11 ).

Measurements (mm). — abd. + app.45.0-48.5,hw31.5-32.0.

differential DIAGNOSIS. — R. chaoi can be separated from all other congeners by the following characters; (1) vestigial or minute non-bifurcated dorsal projection at the dorsal base of the ninth abdominal segment, (2) ochreous face, (3) penile organ with pair of short, broad, squarish-shaped projections, and (4) squarish, peg-like inferior appendages with both upward and outward projections. The closest congeners are R. malaisei LIEFTlNCK (1948) and R.jucundus LIEFTINCK (1948). R. malaisei lacks a prominent dorsal projection on the ninth abdominal segment, which is blunt in profile. The inferior appendages of malaisei lack a ventral projection. R. jucundus has a bifid vestigial abdominal projection and its inferior appendages are broad and flat and not peg-like.

REMARKS. — Three further species of Rhipidolestes species are known from neighbouring Guangdong and Hong Kong. These comprise R. cyanoflavus WILSON (2000) and R. truncatidens Schmidt and janetae WILSON (1997).

Figures

Figs 9-14. Rhipidolestes chaoi sp. n.,♂: (9) head, frontal; (10) penile organ, ventral; (11) penile organ, lateral; (12) caudal appendages, dorsal; (13) caudal appendages, lateral; (14) hindwing.