One of two “species” that Djikstra/Lewington refers to as the Atlantic Darters, the other one being S. striolatum f. nigrifemur (Island Darter). In both cases, whether they are species in their own right or just a variation of S. striolatum (Common Darter) was open for debate. In this case, however, the latest DNA research states that this is not actually a separate species [what a shame, say I] but just a dark morph of Sympetrum striolatum (Common Darter), the darker colouring benefiting survival in a colder, northern climate. However, since Djikstra/Lewington shows and describes them separately, and because I’m not entirely comfortable with the DNA findings, I’m showing them separately as S. striolatum “form” nigrescens knowing that I am not being technically correct. Just look at the three “windows” in the dark side panel of the thorax – it looks like a different creature even if DNA says otherwise.
Having been forced into a trip to Scotland in September, 2012, I deliberately set out to find an example of what is generally known as the Highland Darter. I found just one, a female, and here she is. Given the weather I suffered, I don’t think I’ll be returning any time soon to try harder.
- centre side panel of thorax encloses two/three paler “windows”
- black on frons extends further along eye margins than typical S. striolatum
- side of abdomen with extensive areas of black
- legs can be almost completely black as opposed to with yellow stripes in typical S. striolatum