Priscagrionidae Kalkman & Bybee, 2021

Bybee, Seth M., Kalkman, Vincent J., Erickson, Robert J., Frandsen, Paul B., Breinholt, Jesse W., Suvorov, Anton, Dijkstra, Klaas-Douwe B., Cordero-Rivera, Adolfo, Skevington, Jeffrey H., Abbott, John C., Herrera, Melissa Sanchez, Lemmon, Alan R., Lemmon, Emily Moriarty & Ware, Jessica L., 2021, Phylogeny and classification of Odonata using targeted genomics, Molecular Phylogenetics and Evolution 160, pp. 107115-107115 : 10

Priscagrionidae Kalkman & Bybee fam.n.

(type genus: Priscagrion Zhou & Wilson, 2001 )

— medium sized to fairly large (hindwing 28–30 mm in Sinocnemis , 34–36 mm in Priscagrion ) damselflies with a slender appearance and long legs, restricted to streams in southern China and northern Vietnam. Wings clear except for an apical dark spot in males of Priscagrion , with two Ax in Sinocnemis and three (hindwing) to four (forewing) Ax in Priscagrion ; numerous intercalated veins distally in radial fields, especially in Priscagrion . Arculus roughly at two-thirds of distance between wing base and node. Quadrangle without cross-veins; R4 originates clearly proximal of subnode; IR3 originates at subnode. Pterostigmata rectangular, about one and a half times as long as broad, clearly swollen in the middle; dark. Adults perch with wings outstretched and body held horizontal. Head, thorax and abdomen black witha blue pattern. The slender abdomen has a shining blue dorsal pattern on segment 8–10 (males) and a reduced and duller markings in females. Adult male cerci witha simple forcipate shape, paraprocts nearly as long as cerci and of a simple shape, carrying a tiny apical hook in Priscagrion . Shaft of genital ligula with> 20 setae on each side which areclearly longer than half the width of the shaft. Genital ligula ends in a simple scoop that folds back against the shaft; the internal fold on the genital ligula is slightly drawn-out in Sinocnemis and drawn-out into a long filament in Priscagrion . Nymph of both genera unknown. Included genera: Priscagrion and Sinocnemis .