Cryptophaea vietnamensis (van Tol & Rozendaal, 1995)

(Fig. 11a–i)

Bayadera vietnamensis: van Tol & Rozendaal (1995), pp. 100–103, Figs 13–19, 23 [Holotype and paratypes from Nghe An Prov.]; Yokoi & Kano (2002), p. 24, Fig. 6.

Schmidtiphaea vietnamensis: Wilson & Reels (2003), pp. 254–255, Figs 33–39.

Cryptophaea vietnamensis: Hämäläinen (2003), pp. 446–447; Do & Dang (2007), p. 32, Fig. 15; Yokoi & Souphanthong (2014), pl. 8, Fig. 36.

Materials examined. [Vietnam] 2♂, Mau Son Mt., Loc Binh District, Lang Son Prov., 25.IV.2012, Q.T. Phan leg. (PQTC) ; 2♂ 2♀, Xuan Son National Park, Phu Tho Prov., 15.IX.2015, Q.T. Phan leg. (PQTC) ; 1♂, Cuc Phuong National Park, Ninh Binh Prov., 27.V.1993, H. Karube leg. (PKM) ; 1♂, unknown province, 1994, H. Karube leg. (PKM); 1♂, Xuan Son National Park, Phu Tho Prov., 20.X.2013, T. Kompier leg. (TKC) ; 2♀, Tam Dao National Park, Vinh Phuc Prov., 16.V.2014, Q.T. Phan leg. (PQTC) ; 1♂, Tam Dao National Park, Vinh Phuc Prov., 7.VIII.2013, T. Kompier leg. (TKC) ; 1♂, Quang Binh Prov., 23.VI.2016, T. Kompier leg. (TKC); 1♂, Quang Tri Prov., 5.V.2016, T. Kompier leg. (TKC); 3♂ 1♀, Ba Na Nature Reserve, Da Nang City, 25.V.2015, Q.T. Phan leg. (PQTC) ; 4♂, Kon Ka Kinh National Park, Gia Lai Prov., 23.IV.2013, Q.T. Phan leg. (PQTC) ; 1♀, Chu Mom Ray National Park, Kon Tum Prov., 24.V.2017, Q.T. Phan leg. (PQTC) ; 7♂ 5♀, Bach Ma National Park, Thua Thien- Hue Prov., 28.VI.2017, Q.T. Phan leg. (PQTC); [China] 1♀, Damingshan, Guangxi Prov., 6.VI.2014, F. Hayashi leg. (FHC); [Laos] 1♀, Xam Neua, Houaphan Prov., 8.VI.2017, X. Liu leg. (FHC).

Other materials confirmed by field observations. [Vietnam] Some individuals, Pia Oac, Cao Bang Prov., V, VI.2015, VI.2016, T. Kompier; Some individuals, Mau Son, Lang Son Prov., 28.VI.2014, T. Kompier; Some individuals, Xuan Son National Park, Phu Tho Prov. , V, VI, VII, IX, X.2014, V, VI, VIII, IX, X.2 0 15, VII, VIII.2016, T. Kompier; 3 exs, Hoa Binh Prov., 27.VI.2014, T. Kompier; Some individuals, Tam Dao National Park, Vinh Phuc Prov., VIII.2013, V.2014, VI, VII.2016, T. Kompier; Some individuals, Ba Vi National Park, Ha Noi, V, VII, IX.2013, V.2014, T. Kompier; Some individuals, Cuc Phuong National Park, Ninh Binh Prov., VI.2015, VII.2016, T. Kompier; Some individuals, Thanh Hoa Prov., V, VII.2015, T. Kompier; Some individuals, Quang Binh Prov., V, VI.2016, T. Kompier; Some individuals, Quang Tri Prov., V, VI.2016, T. Kompier; Some individuals, Bach Ma, Thua Thien-Hue Prov., 5–8.VIII.2016, T. Kompier; 1♀, 9.VII.2017, Bac Kan Prov., T. Kompier.

Notes. This species was originally described from central Vietnam as Bayadera vietnamensis (van Tol & Rozendaal 1995) . Later, it was transferred to the genus Schmidtiphaea by Wilson & Reels (2003) based on the specimens from Guangxi, southern China. Hämäläinen (2003) erected the new genus Cryptophaea and moved vietnamensis into it. This species is a medium-sized damselfly with small and slender thorax, hyaline wings, long and narrow abdomen. Body color of male and female varies markedly with age, with immature males and females with purplish-blue markings, which become yellow and greenish blue in the male (Fig. 11a, g–i) and yellow and orange in the female (Fig. 11f). Cerci are strongly curved downward and paraprocts are thin and somewhat curved upward (Fig. 11b–c). Male genital ligula is slender (Fig. 11d–e). Female Cryptophaea vietnamensis is characterized by remarkably large orange-colored markings on the mesepisternum (Fig. 11f).

The shape and coloration of thoracic pattern also vary in males; this variation is to some extent geographical: males in the north (for instance from Cuc Phuong, Ba Vi, Xuan Son and Tam Dao National Parks) or from the Central Highlands (e.g. from Kon Ka Kinh National Park) have a U-shaped mark on the mesepisternum formed by a dorsal stripe and a humeral stripe connected anteriorly (Fig. 11g –i), but the dorsal stripe is missing and the humeral stripe much truncated in specimens from Ba Na or Bach Ma in central Vietnam (Fig. 11a). Males from the north have bluish-green markings when mature (Fig. g–h), but yellowish in males from central Vietnam, for instance from Ba Na, Bach Ma and Kon Ka Kinh (Fig. 11a, i).

Distribution. Vietnam (Cao Bang, Bac Kan, Lang Son, Phu Tho, Hoa Binh, Vinh Phuc, Ha Noi, Ninh Binh, Thanh Hoa, Quang Binh, Quang Tri, Thua Thien-Hue, Da Nang, Kon Tum and Gia Lai Provinces), China (Guangxi Province) (Wilson & Reels 2003), Laos (Bolikhamxay and Houaphan Provinces) (Yokoi & Kano 2002, Hämäläinen 2003, this study).