Sympetrum hypomelas ( Selys, 1884 )

Makbun, Noppadon, 2023, The genus Sympetrum Newman, 1833 in Thailand, with description of S. thailandensis sp. nov. (Odonata: Libellulidae), Zootaxa 5296 (4), pp. 569-581 : 570-574

Sympetrum hypomelas ( Selys, 1884)

( Figs. 1 , 2 , 3 , 7 )

Specimen examined. 3 ♁, 2 ♀, Thailand, Loei province, Phu Kradueng, Si Than , 6-x-2008, N. Makbun leg. ; 2 ♁, same locality and collector, 11-i-2009 ; 1 ♀, same locality and collector, 12-i-2009 ; 1 ♁, same locality and collector, 8-x-2009 . 1 ♀, Thailand, Chiang Mai province, Chom Thong, Ban Luang , 12-viii-2011, N. Makbun leg.

Additional photographic observations. 1 ♁, Thailand, Phitsanulok province, Nakhon Thai, Phu Hin Rong Kla National Park, 17-vii-2011, Nonn Panitvong ; 1 ♁, same locality, 25-ix-2013, Leslie Day; 1 ♁, same locality, 5-ix-2015, Dennis Farrell. 1 ♁, Thailand, Uttaradit province, Nam Pat, Huay Mun, Phu Soi Dao National Park , 17-ix-2013, Thawatchai Ruensongsan; 1 ♁, same locality, 5-xii-2013, Ronnachai Limpakdeesavasd. 1 ♁, Thailand, Nakhon Nayok province, Mueng, Hin Tang, Khao Yai National Park , 9-x-2018, Reinthong Ruangrong ; 1 ♀, same locality, 24-x-2018, Dennis Farrell; 1 ♁, same locality, 26-x-2019, Reinthong Ruangrong; 1 ♁, same locality, 26- vii-2020, Dennis Farrell. 1 ♁, Thailand, Loei province, Phu Ruea, Tha Sala, 28-i-2022, Andaman Kaosung , 1♁, Phu Luang, Phu Luang Wildlife Sanctuary, 30-xi-2022, Paul Farrell. 1 ♁, Thailand, Chiang Mai province, Chom Thong, Doi Inthanon National Park , 15-vi-2022, Andrew Pierce; 1 ♁, same locality, 2-xi-2022, N. Makbun .

Description of male specimen ( Figs. 1–2 , 7a–b )

Head covered with setae ( Fig. 1a–b ). Occipital triangle reddish brown (bright red in life) furnished with setae on the posterior margin. Vertex entirely reddish brown (bright red in life) and unmarked. Antenna entirely black except scape with pale laterally. Postfrons and antefrons entirely yellowish brown (reddish in life). Anteclypeus, postclypeus, gena, mandible and labrum yellow. In the labium, the middle lobe yellow with broad black inner margin in the lateral lobes.

Thorax ( Fig. 1c ). Prothorax black, anterior lobe yellow medially, middle lobe brown (red in life) dorsally, posterior lobe wholly brown (red in life) with a fringe of long yellow setae on upper margin. Synthorax covered with long setae. Mesepisternum and antealar sinus reddish brown (bright red in life). Humeral stripe black and thick, covering humeral suture. Mesepimeron and metepisterum yellow with black at lower part, joining with the humeral stripe and mesokatepisternum. Black stripe broadly covered metapleural suture, expanding from lower part to the area between interpleural and metapleural sutures, covering metastigma. Metepimeron entirely yellow. Legs black except coxa and trochanter brown (reddish in life); inner sides of pro-femora yellowish.

Wings ( Fig. 1d ) hyaline with small yellow patch at base. Pt brown, covering 2 cells below. Ax 8.5 in FW, 6 (left) and 7 (right) in HW. Px 8 (left) and 9 (right) in FW, 8 (right) and 9 (left) in HW. Arc arched and situated between the first and the second antenodal crossvein. Median space entire in both wings. Cubital space with 1 crossvein in both wings. Triangle with one crossvein in FW and entire in HW. Membranule brown.

Abdomen reddish brown (bright red in life), slightly concaved at middle. Ventrolateral part of S2–10 black, forming an irregular band. This black band gradually expand apically in each abdominal segment.

Secondary genitalia ( Fig. 2a ) entire black, furnished with long yellow setae. Genital lobe rectangle-shaped with round corner, bending posteriorly. Hamule triangular with blunt apex bending posteroventrally, with inner hook curved apically. Anterior lamina triangle-shaped.

Vesica spermalis ( Figs. 2b–c ). V1 triangular, V2–3 tubular with wrinkle surface. V4 spoon-shaped, medial lobe well-developed, covering most of cornua except its tip. The exposed cornual apex curved downward.

Anal appendages ( Figs. 2d–f ). Cerci reddish brown (red in life) with black apically, about 2.7 times as long as S10. In lateral view, cerci slightly curved with pointed tip, the ventral margin possess a row of 7 small subapical teeth ( Fig. 2d ). In dorsal view, each cercus slightly curved and parallel-sided, with pointed tip, directed outward. Cerci bend inward to meet each other distally ( Fig. 2e ). When viewed ventrally paraprocts reddish, unmarked, triangular, broad subbasally. Paraprocts, 0.8 times as long as cerci, curve upward, broadest at middle, with hooked tip when views laterally. In ventral view, triangle-shaped, expanded subbasally and tapered to blunt apex ( Fig. 2f ).

Measurements (in mm). HW 27.70, abdomen including appendages 22.70, total body length 35.00 Variations in male specimens. HW 27.61–29.87, abdomen including appendages 22.47–25.82, total body length 34.84–38.07. Ax 7.5–10.5 in FW, 7–8 in HW. Px 8–9 in FW, 8–10 in HW.

Description of female specimen ( Figs. 3 , 7c–d )

General appearance is similar to that of the males. The differences are noted as follow: vertex, postfrons and antefrons reddish yellow. The humeral stripe much broader than that of male. Ax 9.5 in FW, 7 in HW. Px 8 (right) and 10 (left) in FW, 9 (right) and 10 (left) in HW. S2–6 with yellow lateral spot margined with black. Cerci conical with acute tip, reddish brown (yellow in life) dorsally except the apical part, about 1.5 as long as S10. Valvula vulvae black, slightly raised rounded bilobe with shallow and broad incision at middle.

Measurements (in mm). HW 30.30, abdomen including appendages 23.40, total body length 36.00.

Variations in female specimens. HW 28.50–29.8, abdomen including appendages 22.40–24.30, total body length 32.70–35.50

Differential diagnosis. Sympetrum hypomelas is closely similar to those of S. daliensis Zhu, 1999 , S. darwinianum , S. infuscatum ( Selys, 1883) , S. nantouensis Tang, Yeh & Chen, 2013 , S. orientale ( Selys, 1883) , S. risi Bartenef, 1914 , S. thailandensis sp. nov. and S. xiaoi Han & Zhu, 1997 based on penile morphology and red or yellow colour of synthorax and abdomen and side of synthorax have some shades of yellow. However, it differs from all of them by a combination of characters in both sexes. In males, S. hypomelas is characterised by cornua with exposed apices curved downward; cerci slightly curved and parallel-sided in lateral view; mesepisternum red; wing tip hyaline and S4–9 unmarked and mostly red or yellow with black apically. In females, it can be separated from those congeners by cerci black with yellow basiodorsally; S8–10 unmarked; mesepisternum unicoloured and unmarked and wing tip hyaline and valvula vulvae slightly raised rounded bilobe with shallow and broad incision at middle.

Habitat and ecology. Members of this species are found around the open or partly-covered water sources in the forest, such as ponds, lakes, reservoirs, and slow-running streams, on the mountain at altitude of 650–1,650 m asl. They are mostly seen resting on sunny spot on a leaf or twig. The flight season ranges from June to January.

Remark. The hitherto unidentified Sympetrum sp. listed in Hämäläinen & Pinratana (1999) is officially confirmed as S. hypomelas . The Thai specimens show minor differences in the outline of valvulae vulva and antennal scape from the Himalayan specimens in Asahina (1984). The outline of valvulae vulva of the Thai specimens is slightly raised rounded bilobe with shallow and broad incision whereas a bilobe with bluntly triangular apex in Asahina (1984). This is probably due to the angle. The antennal scape of the Thai specimens is black with pale laterally but Asahina (1984) stated that the Himalayan specimens have dark nuance at the base of antenna. The immature males and females are yellow and gradually turn to be bright red when matured ( Fig. 7 ). The distribution of S. hypomelas in Thailand is also increased from two to five provinces, namely Chiang Mai, Loei, Phitsanulok, Uttaradit, and Nakhon Nayok.

Figures

FIGURE 1. General morphology of Sympetrum hypomelas, ♁; (a) habitus in lateral view; (b) head in dorsal view; (c) synthorax in lateral view; (d) right wing in dorsal view.

FIGURE 2. General morphology of Sympetrum hypomelas, ♁; (a) secondary genitalia in lateral view; (b) vesica spermalis in lateral view; (c) vesica spermalis in oblique ventral view; (d) anal appendages in lateral view; (e) anal appendages in dorsal view; (f) anal appendages in ventral view.

FIGURE 3. General morphology of Sympetrum hypomelas, ♀; (a) habitus in lateral view; (b) head in dorsal view; (c) synthorax in lateral view; (d) anal appendages in lateral view; (e) anal appendages in dorsal view; (f) valvula vulvae (white outline) in ventral view.

FIGURE 7. Sympetrum hypomelas in life, males (a–b), females (c–d); (a) Hin Tung, Muang, Nakhon Nayok province, Thailand, 26–vii–2020 (photo by Dennis Farrell); (b) same locality, 3–xi–2018 (photo by Noppadon Makbun); (c) same locality, 24–x–2018 (photo by Dennis Farrell); (d) same locality, 24–x–2018 (photo by Dennis Farrell).