Anoplus plantaris is a small black weevil 1.7 to 2.2 mm. Pronotum lacking microsculpture, smooth and shiny between the punctures, elytral pubescence fine and pointed.

Anoplus roboris is similar but is slightly larger 2.3 to 2.8 mm. The pronotum in A. roboris is microsculptured between the punctures, elytral pubescence includes more conspicuous, apically truncate hairs.

Adult  Leafmine

Adult: Unless identified by a recognised expert, photographic evidence is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used. Note the beetle's size and describe the identifying characters. It is advisable to retain the specimen in case further checks are needed.

Leafmine: Please provide photographs of the mine including a back-lit image. Please also state the host plant.

Likely to be found on Birch.

Adults are present from April until late in the year and occur on birches; Silver birch, Betula pendula, and downy birch, B. pubescens, as well as various hybrids. Mines may be found from late spring.

The larva of the weevil Anoplus plantaris mines the leaves of Birch producing a full depth gallery mine which starts by the midrib and distorts the leaf as it forms. The leaf edge becomes brown.

In the UK it can be fairly frequent across England and Wales though scarce in the West Country and quite local in the north. 

Infrequently recorded in Leicestershire and Rutland.

http://www.leafmines.co.uk/html/Coleoptera/a.plantaris.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/coleoptera/polyphaga/cucujiformia/curculionoidea/curculionidae/curculioninae/anoplini/anoplus/anoplus-plantaris/#:~:text=Anoplus%20plantaris%20(Naez%C3%A9n%2C%201794)&text=The%20larvae%20live%20in%20spring,general%20disfiguring%20of%20the%20leaf.