"Megasphaera butyrica" Hitch et al. 2021 Dataset NCBI Taxonomy Classification phylum Bacillota class Negativicutes order Veillonellales family Veillonellaceae genus Megasphaera species Megasphaera butyrica Name Homonyms Megasphaera butyrica Megasphaera butyrica Hitch et al. 2022 "Megasphaera butyrica" Hitch et al. 2021