Figures 1 –7, 11– 17
Material examined. Holotype ♂, Dajiuhu national wetland park in Shennongjia National Nature Reserve (31 ° 28 ' 47 ''N, 110 °00' 35 ''E), altitude 1754 m, Shennongjia City, Hubei Province, China, Haomiao Zhang leg., 28. VIII. 2013; Paratypes: 1 ♂ 7 ♀, same data as holotype. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China.
Etymology. The name “ Shennong ” refers to the type locality, Mt Shennongjia, an unexplored mountain in central China. “ Shennong ” is also the alternative name of the emperor Yan, a Chinese leader in ancient times. Emperor Yan and emperor Yellow are jointly known as the “The ancestors of the Chinese,” so the name “ Shennong ” also refers to “ China.” It is considered a noun in apposition.
Holotype Male: Head yellowish green with black markings, eyes largely bluish and greenish yellow in lower half in the living individual (Figs. 5–6). Labium yellow with anterior margin black. Labrum largely yellowish green, with a black linear stripe centrally, lower margin black. Mandibles black. Anteclypeus entirely black, postclypeus yellowish green (Fig. 5). Frons yellowish green frontally, with large black spot frontally and black “T” mark dorsally (Fig. 6). Whole face covered with dense setae.
Thorax. Prothorax mainly black with small yellow spots on lower side of hind lobe. Synthorax dark brown with greenish yellow markings as follows (Fig. 1): mesepisternum with antehumeral stripe and an oval spot in posterior lower corner; mesepimeron and metepisternum covered by very large irregular stripe; metepimeron mainly yellow; mesokatepisternum and metakatepisternum yellowish. Legs mainly black except fore coxae with very small yellow spot.
Wings. Wings hyaline, slightly tinted with amber brown. Triangle 4 - or 5 -celled in fore wings and 4 -celled in hind wings, anal loop 6 - or 7 -celled, anal triangle 3 -celled. Anal loop 10 - or 11 -celled. Pterostigma blackish brown on upper side and pale brownish yellow on under side, 3.5 mm in length. Nodal index 14: 20: 19: 15 / 15: 13: 13: 16. Abdomen. Abdomen black with sky blue and yellow markings as follows (Figs. 1–2): S 1 with dorsal blue band posteriorly and very large yellow spot on lower side. Dorsum of S 2 with anterior yellow spot, paired middle yellow stripes and paired posterior blue spots. Side of S 2 with 6 yellow spots: 3 small ones located close to lower margin and 3 large ones irregular in shape (anterior one large, covering auricle, middle one slim and posterior one about half as large as anterior one). Dorsum of S 3 with very small yellow spot anteriorly, paired yellow spots centrally and paired bluish yellow spots posteriorly. Sides of S 3 with very large anterior spot, triangular in shape, median spot and small posterior spot, all yellowish in color. Dorsum of S 4–7 with paired yellow median spots and posterior spots. Lateral side of S 4–7 with two pairs of anterior yellow spots, S 4 with small posterior yellow spot. Dorsum of S 8 with paired very small yellow anterior spots and paired posterior spots, lateral side of S 8 with paired anterior yellow spots. S 9–10 with paired very small posterior spots.
Cerci about 2.5 times as long as S 10, in dorsal view expanded from basal 1 / 5 distally, with inner margin wavy (Fig. 12), in lateral view expanded along apical 3 / 4 with stout apical tooth, sharply pointed at tip (Fig. 11). Epiproct about half as long as cerci.
Paratype female. Head (Fig. 7) and thorax (Fig. 3) very similar to the male, but face paler.
Abdomen shorter and thicker than in males, with more developed yellow markings except postero-dorsal band, which is pale sky blue (Fig. 4). Lateral side of S 1 with a very large spot. Dorsum of S 2 with an anterior spot and paired median and posterior spots; side of S 2 largely yellow. Dorsum of S 3–6 with triangular anterior spots, paired median and posterior spots, and lateral sides of S 3–6 with developed anterior, median and posterior spots. Dorsum of S 7 with very small paired anterior spots and paired median and posterior spots; sides of S 7 with anterior and median spots. S 8 with paired posterior spots on dorsum and paired lateral spots closer to anterior margin. S 9–10 entirely black. Vulvar lamina as illustrated in Figs. 14–15. Cerci black, 1.5 times as long as S 10. Ovipositor short, tip slightly exceeding end of S 9.
Measurements (mm). Holotype: total length 74.0, abdomen (including anal appendages) 56.0, hind wing 46.5. Paratype male: total length 69.0; abdomen (including anal appendages) 52.5, hind wing 45.0. Paratype females: total length 65.0–68.0; abdomen (including anal appendages) 48.0–52.0, hind wing 46.5–48.5.
Distribution. China (Shennongjia, Hubei).
Diagnosis. A brightly marked robust aeshnid, with unique thoracic maculation and anal appendages among Chinese species of Aeshna. This species is very similar to Aeshna petalura Martin, 1908 in the structure of male cerci. These two species possess distally expanded male cerci, which allow distinguishing their males from those of all other described species of Aeshna thus far recorded from China. A. shennong is smaller than A. petalura, and its body markings, especially its thoracic stripes, help separate both male and female from A. petalura. In A. petalura, there are two broad yellowish or greenish stripes across the mesepimeron and metepimeron respectively, separated by a brown area as wide as each stripe, whereas in A. shennong there is a large yellowish or greenish spot covering most of mesepimeron and metepisternum, and the metepimeron is also almost entirely yellowish or greenish yellow (Figs. 1, 3). The apical teeth of the male cerci are much shorter and stronger and visible in dorsal view in A. shennong (Figs. 8, 11), longer and thinner and not visible in dorsal view in A. petalura (Figs. 9, 12). In posterior view, the teeth are directed latero-externally at about 90 ° from the cercus hind margin in A. shennong (Fig. 13) and ventrally or medio-ventrally in A. petalura (Fig. 9).
Notes on biology. The average altitude of Dajiuhu wetlands is above 1700 m. There are over 20 lakes and ponds of different sizes in the wetlands park, and their microhabitats seem to be different. Aeshna shennong was found only at one pond with abundant emergent aquatic vegetation hidden at the foot of the mountain. Only a few males were observed, and females were more abundant in late August. Emergence was recorded during early July, and in late August most specimens were aged, but three specimens (including one paratype male and two female paratypes) were still relatively young and in good condition. Males flew about 3–5 meters above the ponds, usually patrolling for a short time before flying away. Females were seen in greatest numbers around noon and were wary and careful when approaching water. They hovered for nearly one minute and then perched on stems of emergent aquatic plants, laying eggs on the stems at about 20–50 cm above water (Figs. 16–17).