On the taxonomic status of Eumicrotremus eggvinii Koefoed, 1956, Eumicrotremus phrynoides Gilbert et Burke, 1912 and Lethotremus muticus Gilbert, 1896 (Cyclopteridae, Cottoidei) in the light of data on the morphological variability of Eumicrotremus pacificus Schmidt, 1904
A comparison was performed of the morphological variability of the spotted lumpsucker Eumicrotremus pacificus Schmidt, 1904, E. spinosus (Fabricius, 1776), whose synonymy recently included E. eggvinii Koefoed, 1956, and E. gyrinops sensu Stevenson et al., 2017, recently established as the senior synonym for E. phrynoides Gilbert et Burke, 1912 and Lethotremus muticus Gilbert, 1896. Based on a number of morphological differences between E. spinosus and E. eggvinii, corresponding to differences between young and spawning males E. pacificus, it was suggested that individuals E . eggvinii may be nesting males of E. spinosus. It was established that the range of variability of a number of morphological characters of E. gyrinops exceeds that of E. pacificus, which suggests its complex nature. Notable differences in the ratio of the size of the anterior and posterior nostrils, the size of the chin tubes of the seismosensory system and the shape of bone plaques between E. phrynoides and E. gyrinops indicate the validity of E. phrynoides. The absence of an external skeleton in both males and females of L. muticus, unlike other species of the genus Eumicrotremus, allows us to conclude that L. muticus is also a valid species.