Stem miner etc. (Lepidoptera: Gracillariidae) in Arctium

I found a long, contorted stem mine with a central frass line on a dead stem in winter, the larva having mined the stem while it was still alive during the previous growing season. The mine appeared to have originated in the petiole of one of the stem leaves. I am tentatively attributing this record to Marmara sp. based on close similarities with known Marmara stem miners in other hosts.