Subtransnema sp. brachiopods remind me of Douvillina sp. brachiopods. They both look similar in shape and have thin radial lines on the surface of the pedicle valve. The specimen below is from the Hallert member of the Ahbach Formation (Devonian, Givetian stage) near Blankenheim, Germany.
For comparison purposes I've blogged about Douvillina interstrialis from Poland, Douvillina arcuata from Iowa and Douvillina inaequistriata from New York and Ontario.
Thanks go out to Nils for sending me this specimen.