Yunnanosticta siangi Joshi & Sarkar & Sawant & Pawar & Kunte 2024, sp. nov.
Creators: name: Joshi, Shantanu
name: Sarkar, Vivek
name: Sawant, Dattaprasad
name: Pawar, Ujwala
name: Kunte, Krushnamegh
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Platystictidae
Yunnanosticta
Yunnanosticta siangi

description: Yunnanosticta siangi sp. nov. Joshi, Sawant & Kunte
(Figs. 10–15)
Material examined
Holotype. 1 ♂ (IBC-BR546); near Payingdem to Singa road (28.9171 N 95.0375 E, 1293 m ASL), Upper Siang district, Arunachal Pradesh, India; 6.vi.2022; Shantanu Joshi leg.
Paratype. 1 ♂ (IBC-BR545), same details as the holotype.
Paratype. 2 ♀♀ (IBC-BW550: IBC-BW551). Dusskin Hill (28.5466 N 95.0499 E, 906 m ASL), Siang District, Arunachal Pradesh, India; 19.vi.2023; Ujwala Pawar leg.
Etymology. The species epithet is a noun in the genitive case, referring to the Siang River (also known as Brahmaputra). The river is of great cultural significance, and has been the source of folktales, folksongs, and folklore for the people living along the Siang valley (Taggu 2022).
Description of holotype
(Figs.10–11)
Head (Figs. 10a, 11a). Upper 2/3rd of labrum, mandibles and anteclypeus yellow, rest of the head black with glossy green sheen; base of antenna yellow. Eyes glossy, dark brown.
Thorax (Figs. 10a, 11b). Prothorax black with yellow markings as follows: pair of yellow spots on anterior lobe, lateral outer half of median lobes, paired marking along the border of posterior margin.
Pterothorax. Black, marked pale yellow: a tapering stripe on metepisternum broader posteriorly, small spot near posterior margin of metepimeron. Venter yellow.
Legs. Coxae and legs yellow, junction of femur and tibia black.
Wings (Fig. 10b). Hyaline, veins dark brown. Ab present, connected to Ac, forming a ‘Y’ shape. Ax 2; Px 19 in FW and 18 in HW. Arc forming slightly distal to Ax 2. One postcubital vein in all wings. CuP meets the wing margin between Px 9 & 10 in FW and Px 13 in HW. CuP meets wing margin at ca level of Px 9/ 10 in FW and Px 13 in HW. R 4 arises from a level of ca subnodus in FW, proximal to subnodus in HW. R 4 meets wing margin at level distal to distal end of Pt in FW and proximal to proximal end of Pt. R 3 arises at a level of ca just proximal to Px 8 in FW and at Px 6 in HW. IR 2 arises at the level of ca Px 9 in FW and Px 8 in HW. Pt dark brown, rhomboid, wider in HW; slightly larger than one cell beneath, anterior margin more slanted than posterior margin. Apex of wings falcate, slightly pointed postero-laterally.
Genital ligula (Fig. 11e–g). Base black. Apical segment translucent tinted pale yellow, narrower than preceding segment at base, curved upwards and expanded into two arms. The two arms are curved, ending in blunt rectangular apex. At the base of two arms there is a part of very short spurs.
Abdomen (Fig. 10a). Black, marked with pale yellow with slight blue tinge towards apices: ventrally on S1–2, basal annules on S3–8, annules longer ventrally on S7–8 reaching almost 3/4th of the length ventrally.
Caudal appendages (Figs. 11c–d). Dark brown covered with yellow hair, paraprocts slightly longer than cerci. Cerci with straight margins, fusiform, curved slightly upwards, ending with a short flap curved downwards and inwards at about 600 degrees, pointed at apex. Paraproct broader at base, tapering; apices pointed, curved upwards and inwards.
Measurements. Abdomen + caudal appendages = 36.2, HW = 24.7–25.4, FW = 25.6–26.2.
Variation in paratype male (Fig. 12).
Px 18 (left)–19 (right) in FW, 17 (right)–18 (left) in HW. Px R 3 arises at Px 7 in FW, Px 6 in HW, IR 2 arises at a level one Px distal in all wings.
Measurements. Abdomen + caudal appendages = 35.5, HW = 24.4–25.2, FW = 25.1–25.3.
Description of paratype female (IBC-BW550)
(Fig. 13)
Head (Figs. 13a, c). Labium dark brown. Labrum except nasal 1/3rd, anteclypeus blue. Mandibles pale yellow. Rest of the face glossy black, base of antennae dark yellow, pedicel missing. Eyes dark brown.
Thorax (Fig. 13a, d) glossy black. Prothorax marked as follows: bright yellow markings on paired oval spots on anterior lobe; medial lobe dark yellow with variegated bright oval markings; posterior lobe with faint yellow stripe along the base and faint markings along the margin.
Pterothorax. Metepisternum with a yellow stripe covering it almost entirely tapering slightly anteriorly. Metepimeron with yellow stripe covering 1/4th ventrally, faint anteriorly; triangular markings at the posterior dorsal margin. Venter yellow. Legs and coxae bright yellow except black stripes across junction of femur and tibia.
Wings (Fig. 13b). Tinted faint brown, veins dark brown. Ab joined to Ac vein with short stalk forming a ‘Y’ in all wings. Ax 2; Px FW 21 (left)–22 (right), HW 20. Arc arising slightly posterior to Ax 2. One postcubital vein in all wings. CuP meets wing margin at level of ca Px 10 in FW and Px 13 in HW. R 4 arises at a level of subnodus in FW, slightly proximal in HW. R 4 meets wing margin at a level slightly distal to distal end of Pt. R 3 arises at a level proximal to Px 8, IR 2 arises at a level between: Px 9 & 10 in FW and Px 8 & 9 in HW. Px dark brown, larger than one cell below, proximal margin slanted. The apex of wings falcate.
Abdomen (Fig. 13a). Dark brown to black, S1–8 with yellow basal annules at the anterior margin, prominent on S3–7, small on S8. S9 with a yellow dorsal marking at base extending about halfway posteriorly. S8–9 faintly blue on dorsum, coloration not clearly visible post-mortem.
Caudal appendages (Figs. 13e–f). Cerci dark brown, conical, pointed slightly inwards and upwards, apices blunt. Tubercle short. Ovipositor yellow at base, dark brown medial and black on top. Apices pointed dorsally with a thick translucent yellow lamina.
Measurements. Abdomen + caudal appendages = 33.5, HW = 25.6–26.1, FW = 26.6–27.
Variation in paratype female
Wings tinted slightly more prominently brown. Legs yellow, tinted orange. Yellow markings on medial and posterior lobes of prothorax are more prominent. The markings on abdomen are less bluish, darker yellow. Px 22 in left & 23 in right FW, 20 in left & 21 in right HW. R 3 arises at a level ca Px 8 in FW and 7 in HW. IR2 arising at a level two Px proximal to R3 on right side, one Px proximal to R 3 in HW.
Measurements. Abdomen + caudal appendages = 35.1, HW = 27.2, FW = 27.8–27.9.
Note on the female description
We did not observe the male and female described here in copula. But, due to the close vicinity of the collection localities and similarity in markings of thorax and abdomen we have ascribed the same specific identity to males and females. Above description of female paratype is done with supposition.
Diagnosis
This species is placed in the genus Yunnanosticta based on two characters (Dow & Zhang 2018): CuP meets wing margin half-way or beyond (Figs. 10b, 12b, 13b), and the shape of male genital ligula (Figs. 11e–g).
The genital ligula of Y. siangi is similar to that of Y. cyaneocollaris Dow & Zhang but the spur at the base of the apical segment is much shorter in Y. siangi. Paraproct is simpler, more pointed and thinner in Y. siangi, in Y. cyaneocollaris and Y. wilsoni Dow & Zhang it is stouter and notched (Fig. 14). Yunnanosticta siangi also differs from Y. cyaneocollaris and Y. wilsoni by the presence of markings on pterothorax (thorax unmarked in latter two species) and the smaller extent of blue coloration on S8–9, especially on S8 (extensively blue on dorsum of S 8–9 in other two species). Anterior lobe of prothorax with large, paired spots in Y. siangi (unmarked in Y. cyaneocollaris and Y. wilsoni). The posterior lobe of prothorax is only faintly marked on lateral margins in Y. siangi (extensively blue in Y. cyaneocollaris and Y. wilsoni).
Since females of previously described Yunnanosticta are unknown we cannot provide a diagnosis for females. But female Y. siangi differs from male Y. cyaneocollaris and Y. wilsoni by the markings of prothorax (paired spots on anterior lobe in Y. siangi), pterothorax (lateral yellow stripe in Y. siangi) and abdomen (large paired spots on S9).
Presence of thoracic markings and larger size differentiate Y. siangi from the two previously described species, but we feel that these differences do not warrant the placement of Y. siangi in a new genus at this stage since the wing venation characters which were stressed in the diagnosis of the genus (Dow & Zhang 2018) match well with Y. siangi. Our collection locality is relatively close (straight-line distance ~ 545 km) to Yunnan, China where the two previously described species were found (Fig. 4).
Additionally, Y. siangi is similar in appearance to species of the Drepanosticta carmichaeli -group in terms of lateral thoracic pattern, simple caudal appendages, and the shape of genital ligula. However, all these Drepanosticta spp. have inwardly curved male cerci which are dorso-ventrally flat near the apex. Further most of these species have CuP ending at or around mid-point of wing margin unlike Y. siangi. However, it will be interesting to reexamine the wing venation of species of the D. carmichaeli -group to establish the correct generic placement. Above all, molecular phylogenetic study is needed to determine affinities within mentioned genera in species-groups in Platystictidae of India and wider region.
Habitat and behavior
This species was observed exclusively in dark areas of small, shaded streams along small tributaries of the Subansiri river at 900–1300 m. These fast-flowing shallow streams were <1 m in width, <0.5 m in depth with fine gravel as the substrate. Individuals were observed resting on bushes very close to or over the stream, staying close to the forest floor (Fig. 15).
description: Published as part of Joshi, Shantanu, Sarkar, Vivek, Sawant, Dattaprasad, Pawar, Ujwala & Kunte, Krushnamegh, 2024, Description of Protosticta khasia sp. nov. and Yunnanosticta siangi sp. nov., with new records of P. samtsensis Gurung & Phan, 2023 from Northeast India (Odonata: Zygoptera: Platystictidae), pp. 348-370 in Zootaxa 5448 (3) on pages 361-369, DOI: 10.11646/zootaxa.5448.3.2, http://zenodo.org/record/11231707