Two isolates, with optimum growth temperature and pH of about 30 °C and 6.0–7.0, were recovered from a borehole head of a mineral water aquifer in Portugal. The closest relatives based on 16S rRNA gene sequence analysis were species of genera of the family Chitinophagaceae . Strains L2-4^T and L2-109 formed translucent colonies and non-motile pleomorphic cells. Strains were strictly aerobic, and oxidase- and catalase-positive. The major fatty acids of strains L2-4^T and L2-109 were 17 : 0 iso 3-OH, 15 : 0 iso and 15 : 1 iso G. The major polar lipids were phosphatidylethanolamine, one unidentified phospholipid, four unidentified aminophospholipids, four unidentified aminolipids and three unidentified polar lipids. Menaquinone 7 was the only respiratory quinone. The G+C content of the DNA of strains L2-4^T and L2-109 was 42.0 and 41.4 mol%, respectively. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics, strains L2-4^T ( = CECT 8122^T = LMG 26919^T) and L2-109 ( = CECT 8121 = LMG 26920) are considered to represent a novel species of a new genus, for which the name Heliimonas saccharivorans gen. nov., sp. nov. is proposed. The type strain of Heliimonas saccharivorans is L2-4^T. Due to additional results obtained in this study an emended description of Filimonas lacunae is provided.