Any ideas on genus or species?
This mite has a stylophore, and the palps look like they have the thumb-claw processes so that leads me to Tetranychidae. The arrangement of the long, spiky setae is pretty interesting. All of them are set on raised bases. There are 3 pairs of setae down the middle of the back of the opisthosomal region. The other long, spiky setae are set laterally on the back. There are 2 set singly on each side of the prodorsum. Then, there are 3 pairs set along each side of the opisthosoma. And a group of 3 spiky setae on each side of the posterior edge of the opisthosoma.
The adult mites were brick red when alive. These were found on a hazelnut leaf. There was leaf-stipling, but no webbing to speak of. The eggs were also red. I thought this could be a European red mite, but the arrangement of the spiky setae doesn't seem right from what I can tell.