A group of five Gram-negative strains isolated from clams (Venerupis decussata and Venerupis philippinarum) in Galicia (NW Spain) were analyzed using a polyphasic taxonomic approach. The strains were non-motile, strictly aerobic rods, and formed yellow-pigmented colonies. Based on 16S rRNA gene sequence similarity, the clam isolates belonged to the Lacinutrix genus, within the Flavobacteriaceae family, and showed the highest sequence similarities with Lacinutrix mariniflava (97.0%) and Lacinutrix algicola (96.9%). The DNA G + C content of the designated type strain Cmf 20.8T was 34.1%, which was within the range of the other species in the genus (29.0–37.0%). The main cellular fatty acids of the type strain Cmf 20.8T were iso-C15:0 3-OH, iso-C15:1 G, iso-C15:0 and iso-C17:0 3-OH. The DNA–DNA analysis value of strain Cmf 20.8T with L. mariniflava AKS292T was 51% and with L. algicola AKS293T it was 56%. Phenotypic data showed that the isolates could be differentiated easily from the other species of the genus. On the basis of these results, the strains represent a novel species of the genus Lacinutrix, for which the name Lacinutrix venerupis sp. nov. is proposed, with Cmf 20.8T (=CECT 8573T = DSM 28755T) as the designated type strain.