Sympetrum thailandensis Makbun 2023, sp. nov.
Creators: name: Makbun, Noppadon
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Libellulidae
Sympetrum
Sympetrum thailandensis

description: Sympetrum thailandensis sp. nov.
(Figs. 4–6, 8)
Holotype. 1 ♁, Thailand, Nakhon Nayok province, Mueng, Hin Tang (1,235 m asl), 3-xi-2018, N. Makbun leg.
Paratypes. 3 ♁, 1 ♀, locality and date same as for holotype, N. Makbun leg.
Additional photographic observations. 1 ♁, Thailand, Nakhon Nayok province, Mueng, Hin Tang, 9-x-2018, Reinthong Ruangrong; 1 ♁, same locality, 25-x-2018, Dennis Farrell; 1 ♀ (teneral), same locality, 26-vii-2020, Dennis Farrell; 1 ♁, 1 ♀ (copula), same locality, 3-x-2020, John Sim, 1 ♁, same locality, 23-viii-2021, Reinthong Ruangrong.
Etymology. The specific epithet “ thailandensis ” refers to the country, Thailand, where this new species was discovered.
Description of holotype (Figs. 4–5)
Head covered with black setae (Figs. 4a–b). Compound eyes brownish yellow (upper part red and lower part brown in life). Occipital triangle reddish. Vertex black with reddish yellow dorsally. Antenna entirely black. Postfrons reddish yellow with a black basal band, but the margin of the band ambiguous. Antefrons and postclypeus reddish yellow. Anteclypeus, gena, mandible and labrum yellow. In the labium, the middle lobe yellow with narrow black inner margin in the lateral lobes.
Thorax (Fig. 4c). Prothorax black, posterior lobe red dorsally with a fringe of long brown setae on upper margin. Synthorax covered with long setae. Mesepisternum and antelar sinus brown (reddish brown in life). Humeral stripe black and thick. Mesepimeron and metepisterum red with black at lower part, connecting with the humeral stripe. Black triangular stripe covered interpleural suture and metastigma, reaching about half of its length. Metapleural suture covered with black narrow stripe. The area between the interpleural and metapleural stripes blackish brown. Metepimeron entirely red. Leg black except coxa and trochanter reddish brown; inner sides of pro-femur yellowish; femur with short robust spines; tibia with numerous long spines.
Wings brown with small yellow basal patch (Fig. 4d). Pt brown with darken costal margin, covering 2 cells below. Ax 8.5 in FW, 6 in HW. Px 7 (right)–8 (left) in FW, 7 (left)–8 (right) in HW. Arc arched and situated between the first and the second antenodal crossveins. Median space entire in both wings. Cubital space with 1 crossvein in both wings. Triangle with one crossvein in FW and entire in HW. Anal loop 18 (left)–19 (right) in HW. Membranule brown.
Abdomen typical for the genus, bright red in color. S1 reddish brown. S2 red with black basally. S3–7 entirely red and unmarked. S8–9 red with black middorsal marking and apico-lateral band. S10 black with two red lateral irregular spots.
Secondary genitalia (Fig. 5a) entire black with yellow long setae. Genital lobe erect, semicircular. Hamule long triangular, blunt tip, directing posteroventrally, with pale triangular inner hook. Anterior lamina semicircular.
Vesica spermalis (Figs. 5b–c). V1 black, large, rather semicircular in lateral view, covered with yellow lone setae. V2 pale, tubular with wrinkled surface, slightly expanded apically. V3 dark, short, and curved posteroventally. V4 dark, spoon-shaped; medial lobe well-developed, curved, covered most of cornua except its apical part (Fig. 5b). The visible apical part of cornua filamentous with pointed tip, curved downward in lateral view. In ventral view, V4 semicircular with ventral crest (or medial nodule) at middle; medial lobe triangular covering cornua except its apical part; cornua bending sideway with exposed apical part curved downward (Fig. 5c).
Anal appendages (Figs. 5d–f). Cerci, about 3.5 times as long as S10. In lateral view, cerci curved with pointed tip, the ventral margin possess a row of 6 small blunt subapical teeth (Fig. 5d). In dorsal view, cerci black with red basally, straight and slightly convergent, broad basally, with pointed tip, directed outward (Fig. 5e). Paraprocts 0.8 times as long as cerci. In lateral view, paraproct curved upward at middle, tapered to its hooked tip. In ventral view paraprocts triangular, broad at base, concaved subbasally and tapered to its blunt apex (Fig. 5f).
Measurements (in mm). HW 26.64, abdomen including appendages 22.38, total body length 35.04
Variations in male paratypes. Male paratypes are larger in size, HW, length of abdomen including anal appendages and total body length (27.50–28.16, 22.74–23.40, and 35.14–37.33, respectively). Ax and Px in HW are more than the holotype (7 and 8–9, respectively). The number of cells in anal loop of one paratype is less (17–18) and the other one is more (19–20) than that of the holotype.
Description of paratype female (Fig. 6)
Similar to holotype male unless otherwise stated (Fig. 6a). Postfrons, antefrons and postclypeus yellow (Figs. 6b). Side of synthorax pale yellow covered with a black complete stripe on humeral suture and two incomplete stripes covered separately on metapleural and interpleural sutures. The area between the interpleural and metapleural stripes blackish brown (Fig. 6c). Wings brownish with yellow patch at the base, Px 8 in FW and 7 (right)–8 (left) in HW. Anal loop 19 (right) and 21 (left) in HW. Abdomen cylindrical, yellow with red dorsally; S7 with black apico-lateral spot; S8–9 with black apico-lateral marking and middorsal spots; S10 black with reddish yellow lateral spot (Fig. 6d). Cerci black, conical with tip pointed sideway, about 1.8 times as long as S10, in top view (Fig. 6e). Valvula vulvae black, short, bluntly triangular-tip bilobe (Fig. 6f).
Measurements (in mm). HW 29.51, abdomen including appendages 23.10, total body length 36.13
Differential diagnosis. Following Pilgrim & von Dohlen (2012), who categorised Sympetrum into six speciesgroups based on penile morphology, S. thailandensis belongs to infuscatum -group. With five more species added to the group as Tang et al. (2013) suggested, the infuscatum -group so far comprises 10 species, viz. S. daliensis, S. darwinianum, S. gracile Oguma, 1915, S. hypomelas, S. infuscatum (Selys, 1883), S. maculatum Oguma, 1922, S. nantouensis, S. orientale, S. risi and S. xiaoi (Pilgrim & von Dohlen 2012; Tang et al. 2013).
Sympetrum thailandensis is most similar to S. darwinianum in the infuscatum -group. They share synthorax and abdomen yellow to red; S8–9 red with middorsal spots; wing tip hyaline and cornua with exposed apices curved downward. However, the new species can be separated from the congener by a combination of following characters (character of S. darwinianum for comparison is in paratheses): in males, cerci curved with pointed tip in lateral view (vs. slightly curved and parallel-sided); mesepisternum reddish brown (vs. red) and cerci are black with red basally (vs. entirely pale red or yellow).
In females, S. thailandensis can be differentiated from S. darwinianum by a set of characters as follows: cerci entirely black (vs. entirely yellowish or reddish); mesepisternum unicoloured and unmarked (vs. dark brown or black with pale yellow stripe) and valvulae vulva short with bluntly triangular-tip bilobe (vs. very small or vestigial).
Habitat and ecology. The habitat of S. thailandensis is a small seasonal pond surrounded trees and grasses near the parking area of the tourist attraction. It coexists with S. hypomelas at restricted altitude (1,200 –1,300 m asl) at the type locality. It is found perching on leaf in sunny day but disappears when it is overcast. So far, this new species is distributed restrictedly, compared to the congener species, S. hypomelas, in Thailand (Fig. 9). The emergence was observed in late July. Mating and oviposition was recorded from late October to early November. An ovipositing female, with guarding male, was observed hovering about a meter above the water for a while. Then, when ready, the female flicked a light green egg into the water at a time. The flight season ranges from July to November.
description: Published as part of Makbun, Noppadon, 2023, The genus Sympetrum Newman, 1833 in Thailand, with description of S. thailandensis sp. nov. (Odonata: Libellulidae), pp. 569-581 in Zootaxa 5296 (4) on pages 574-578, DOI: 10.11646/zootaxa.5296.4.6, http://zenodo.org/record/7984426