Yunnanosticta cyaneocollaris Dow & Zhang 2018, sp. nov.

Yunnanosticta cyaneocollaris sp. nov.

(Figs 2, 4, 6, 8, 11, 13, 15, 17, 19, 21, 23, 24, 26)

Drepanosticta sp. 4;— Zhang 2017: Fig. 24d (photograph of male in life).

Holotype. ♂, Tongbiguan National Nature Reserve (24.5833 N, 97.5856 E, ca 1220 m), Yingjiang County, Dehong Dai & Jingpo Autonomous Prefecture, Yunnan, China, 23 vi 2015, leg. H.M. Zhang, to be deposited in BMNH.

Paratypes. 1 ♂, Tongbiguan National Nature Reserve (24.6636 N, 97.5883 E, ca 740 m), Yingjiang County, Dehong Dai & Jingpo Autonomous Prefecture, Yunnan, China, 0 6 vii 2014, leg. H.M. Zhang, in the collection of the H.M. Zhang.

Etymology. The species is named cyaneocollaris, a noun in apposition: meaning “blue neck”, in reference to the largely blue prothorax.

Description of holotype. Head (Fig. 2). Labium pale brown. Labrum whitish in basal ca two-thirds, dark brown below. Mandible bases very dark brown, whitish in corner adjacent to labrum and clypeus. Anteclypeus whitish, postclypeus shining black. Genae dark brown, frons obscurely brown and black. Vertex, occiput black, small whitish sub triangular marking at front median ocellus, small whitish marks at outer sides lateral ocelli. Underside of head shining black. Ratio of width of compound eye to width of vertex measured at level of lateral ocelli ca 0.6. Transverse occipital carina not very prominent. Ocelli whitish. Antenna with scape mostly pale, pedicel greyish, hardly narrower than scape, slightly expanded apically, rest missing.

Thorax. Prothorax (Figs 4, 6) with anterior pronotal lobe black, propleuron yellow, narrowly dark brown at rear, middle pronotal lobe mottled blue and yellow, posterior pronotal lobe blue, narrowly framed in black. Anterior pronotal lobe with anterior carina same height as highest part of raised part. Posterior pronotal lobe short, simple, collar-like. Synthorax (Fig. 8) entirely brown, including venter, with small blue marks just below interpleural suture, near antealar carina on metepisternum, Venter of synthorax dark brown. Legs (middle right leg absent below trochanter): almost entirely yellowish, brown mark rear of coxae on middle and posterior pairs, narrowly dark around joint of femur and tibia, with faint, partial, poorly defined greyish ring around femur at ca two-thirds of its length. Wings: 15 Px in Fw, 14 Px in Hw. Vein Ab present, joined to Ac to form Y, single postcubital vein present in all wings. Arculus arising at or slightly distal to Ax2. R4 arising proximal to subnodus, IR3 distal to subnodus, joined to R4 by short stalk. CuP meeting wing margin at ca level of Px 6 in Fw, Px 9 in Hw; R4 meets the wing margin just beyond level of distal end of Pt. R3 arises at ca level of Px 6 in Fw, Px 5 in Hw, IR2 ca 1 Px further distal except in left Hw where 2 Px further distal. Both R3 and IR2 meet the wing margin at the falcate tip. Pterostigma almost rhomboidal, black with narrow pale border, covering one underlying cell.

Abdomen. S1 brown. S2 brown with narrow transverse pale dorsal basal mark. S3–7 largely brown, becoming darker apically and on successive segments, with pale dorsal basal mark, separated from diffuse sub basal pale mark along lower margin of tergite, dorsal mark becoming fainter on successive segments, sub basal mark longer. S8 similar but dorsal basal marking very small, irregular (Figs 15, 17), pale blue dorsal marking in apical ca two thirds (Fig. 17). S9 pale blue except black lower laterally, S10 black with tiny, faint blue mark on left side dorsally (Fig. 17). Anal appendages (Figs 19, 21, 23) dark brown and black. Cerci short, simple, in lateral view (Fig. 19) narrowing gradually from base to rounded apex, curved gently up then down to apex, a strong but narrow ventral tooth present; in dorsal (Fig. 21) view bulbous, subcircular, apex broad and slightly, very shallowly bifurcated. Paraprocts a little longer than cerci (Fig. 19), in lateral view subtriangular for most of their length, bifurcated at apex into rounded outer branch, best seen in ventral view (Fig. 23) and with up turned inner branch, best seen in lateral view (Fig. 19); in ventral view the inner branch appearing short, pointed. Note that in Figure 21 the difference in length between cerci and paraprocts appears greater than it really is, this is because of the angle from which the drawing was made.

Genital ligula (Figs 11, 13). Terminal segment narrower than penultimate segment, relatively short, apically divided into two arms lying on either side of shaft, expanded apically and curved forward (Fig. 11). Internal fold very large.

Measurements (mm). Abdomen without anal appendages ca 25, cercus ca 0.3, Hw ca 16.5.

Female. Unknown.

Variation in paratype male. No significant variation was found in the single paratype, except that the blue dorsal mark on S8 extends almost the entire length of the segment (see Fig. 26).

Diagnosis. The male is easily separated from all other known members of the Platystictidae except Y. wilsoni by the characters defining the genus. It is separated from Y. wilsoni by the dark venter of the synthorax, the very large internal fold and differently shaped terminal arms of the genital ligula, the cerci slightly shorter than the paraprocts, the subapical tooth on the cercus positioned ventrally and longer than in Y. cyaneocollaris, and the shorter inner branch of the paraproct.

Remarks. The habitats of this species are seepages and narrow streams in the shade. The holotype male was collected at the same locality as that of Y. wilsoni. The paratype male was collected at a lower altitude of ca 740m, where it was perching on a leaf at a stream margin. The stream is in shady forest, about 0.5m in width and rather shallow, the substrate is silver sand. Except for two paratype males of Y. wilsoni, no other species was found at this location. This species appears to occur at very low densities.