English: Derjugin's leatherfin lumpsucker, Eumicrotremus derjugini. (A) Young, Zub Island; forehead prominent, snout abruptly vertical; spiny plates weakly developed and small, appearing in three longitudinal short rows, 3-4 plates each; color is light brown with dark twisting lines. (B) Same specimen from below; sucking disk consists of transformed ventral fins. (C) Juvenile TL 14 mm, Prince Rudolf Island, ZIN 6-013/10; the first dorsal fin already covered by thickened skin. (D) Same specimen after preservation.