A moderately halophilic, strictly anaerobic bacterium, designated 37HS60T, was isolated from an olive mill wastewater in southern Morocco (Marrakesh). The cells were straight, motile and stained Gram-positive, forming spherical and terminal spores and with an atypical thick and stratified multilayered cell wall. Major fatty acid components were iso-C17 : 1v10c or anteiso-C17 : 1v3c (19.3 %), C14 : 0 (14.3 %), C16 : 1v7c (9.9 %), C16 : 1v7c DMA (8.5 %) and C16 : 0 (7.6 %). Strain 37HS60T grew from 20 to 50 6C with an optimum at 40-45 6C, and growth was observed from pH 5.5 to 8.5 with an optimum of 6.8. The salinity range for growth was 10-100 g NaCl l"1 with an optimum at 50 g NaCl l"1. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 37HS60T fell within the evolutionary radiation enclosed by cluster XII of the Clostridium subphylum. Strain 37HS60T exhibited highest 16S rRNA gene sequence similarity of 92.0% with Caloranaerobacter azorensis and 90.6% with Clostridium purinilyticum. Moreover, 37HS60T did not grow on basal medium with hexose or pentose sugars as carbon and energy sources. Pyruvate, fumarate and succinate were the best substrates for 37HS60T growth with 1.0 g yeast extract l"1. The DNA G+C content as 33.0 mol%. Due to its phenotypic and genotypic characteristics, isolate 37HS60T is proposed as a novel species of a new genus, Clostridiisalibacter paucivorans gen. nov., sp. nov. The type strain is 37HS60T (5JCM 14354T5CCUG 53849T).