Somatochlora, or the striped emeralds, is a genus of dragonflies in the family Corduliidae with 42 described species found across the Northern Hemisphere.
Taxonomy The name Somatochlora is derived from the Greek soma (body) and khloros (green). The species Corduliochlora borisi was formerly treated as a member of Somatochlora.
A 2025 article in Systematic Entomology examined the phylogeny of Somatochlora and proposed the following phylogenetic tree:
Description
Members of this genus are medium-sized dragonflies with dark bodies and a metallic green lustre. The eyes are brilliant green, and many species have dull to bright yellow markings on the thorax and/or abdomen. The abdomens of males are distinctive, with the first two segments bulbous-shaped, the third constricted, and the rest of the abdomen club-shaped with a straight ending. Females have abdomens with straighter sides. Identifying these dragonflies to species can be difficult. The cerci of males, on the tip of the abdomen, are distinctively shaped in each species, as are the subgenital plates on female abdomens. In some species, the subgenital plate is large and projecting, and is used as a "pseudo-ovipositor" for inserting eggs into a substrate.
Distribution
Somatochlora species are found across the Northern Hemisphere in Europe, Asia, and North America, with some species extending into arctic regions north of the treeline. Some species extend south to Spain, Turkey, northern India, northern Vietnam, Taiwan and the Southern United States. At least one species, S. semicircularis, may be found at altitudes up to . In North America, most species live in the boreal forest and/or the Appalachian Mountains.
Life history
Somatochlora larvae typically live in bogs, fens, and/or forest streams, with some species found in lakes. They do not occur in marshy ponds. Many species are limited to very specific habitats and are rare and local. Adults feed in flight and may occur at some distance from their breeding habitat in mixed swarms.
Species
Somatochlora is the most diverse group within the Corduliidae. Of the 42 described species listed below, 25 are North American, 16 are Eurasian, and one is circumboreal (S. sahlbergi). Two additional fossil species have been assigned to this genus: S. brisaci, based on a wing from the Upper Miocene in France, and S. oregonica, based on two wings from the Oligocene in Oregon.
Image Species Common name(s) Distribution Somatochlora albicincta ringed emerald Canada, northern United States Somatochlora alpestris alpine emerald Europe and Asia Somatochlora arctica northern emerald Europe and Asia Somatochlora brevicincta Quebec emerald Canada, northern United States Somatochlora calverti Calvert's emerald southeastern United States Somatochlora cingulata lake emerald Canada, northern United States Somatochlora clavata Japan and Korea Somatochlora daviesi Bhutan, Nepal, and India Somatochlora dido China and Vietnam Somatochlora elongata ski-tipped emerald, ski-tailed emerald northeastern North America Somatochlora ensigera plains emerald central North America Somatochlora exuberata Japan and eastern Russia Somatochlora filosa fine-lined emerald southeastern United States Somatochlora flavomaculata yellow-spotted emerald Europe Somatochlora forcipata forcipate emerald Canada, northern United States Somatochlora franklini delicate emerald Canada, northern United StatesSomatochlora georgiana coppery emerald eastern United States Somatochlora graeseri east Asia Somatochlora hineana Hine's emerald Ontario and midwest United StatesSomatochlora hudsonica Hudsonian emerald western and central Canada, northwestern United States Somatochlora incurvata incurvate emerald northeastern North America Somatochlora kennedyi Kennedy's emerald Canada, northeastern United States Somatochlora linearis mocha emerald eastern North America Somatochlora lingyinensis Zhejiang Somatochlora margarita Texas emerald Texas and Louisiana Somatochlora meridionalis Balkan emerald southeastern Europe Somatochlora metallica brilliant emerald Europe Somatochlora minor ocellated emerald Canada, northern United States Somatochlora ozarkensis Ozark emerald Arkansas, Kansas, Missouri and Oklahoma Somatochlora provocans treetop emerald southeastern United States Somatochlora sahlbergi treeline emerald northwestern Canada, Alaska, northern Russia, Scandinavia Somatochlora semicircularis mountain emerald western North America Somatochlora septentrionalis muskeg emerald Canada Somatochlora shanxiensis Hubei, Shanxi Somatochlora shennong Guangxi, Hubei Somatochlora taiwana Taiwan Somatochlora tenebrosa clamp-tipped emerald eastern North America Somatochlora uchidai Japan, China and Russia Somatochlora viridiaenea Japan, eastern Russia Somatochlora walshii brush-tipped emerald Canada, northern United States Somatochlora whitehousei Whitehouse's emerald Canada, northwestern United States Somatochlora williamsoni Williamson's emerald eastern North America
References