Petiole and leaf blade miner (Undetermined) in Sanicula

I found a single example of this mine in a Sanicula basal leaf in early October, traveling from the leaf blade into the petiole. I was unable to locate the culprit inside the mine. The shape and color of the part of the mine in the petiole were very similar to the sign left by the Neolasioptera in this host (0491), which I have recorded from basal leaf petioles. I have chosen to place this mine in a separate record since I have never heard of a cecidomyiid mining in a leaf blade, but the resemblance is certainly interesting.