A Gram-negative, rod-shaped, sulfate-reducing bacterium (strain JS_SRB250Lac(T)) was isolated from a tidal sand-flat in the German Wadden Sea. 16S rRNA gene sequence analysis showed that strain JS_SRB250Lac(T) belonged to the Desulfobulbaceae (Deltaproteobacteria), with Desulfopila aestuarii MSL86(T) being the closest recognized relative (94.2 % similarity). Higher similarity (96.6 %) was shared with 'Desulfobacterium corrodens' IS4, but this name has not been validly published. The affiliation of strain JS_SRB250Lac(T) to the genus Desulfopila was further supported by analysis of aprBA gene sequences and shared physiological characteristics, in particular the broad range of organic electron donors used for sulfate reduction. Compared with Desulfopila aestuarii MSL86(T), strain JS_SRB250Lac(T) additionally utilized butyrate and succinate and grew chemolithoautotrophically with hydrogen as an electron donor. CO dehydrogenase activity was demonstrated, indicating that the reductive acetyl-CoA pathway (Wood-Ljungdahl pathway) was used for CO(2) fixation. Results of cellular fatty acid analysis allowed chemotaxonomic differentiation of strain JS_SRB250Lac(T) from Desulfopila aestuarii MSL86(T) by the presence of C(17 : 0) cyclo and the absence of hydroxy and unsaturated branched-chain fatty acids. Based on phylogenetic, physiological and chemotaxonomic characteristics, strain JS_SRB250Lac(T) represents a novel species of the genus Desulfopila, for which the name Desulfopila inferna sp. nov. is proposed. The type strain is JS_SRB250Lac(T) (=DSM 19738(T) =NBRC 103921(T)).