Clostridium lacusfryxellense Spring et al. 2003 Spring S. Merkhoffer B. Weiss N. Kroppenstedt R.M. Hippe H. Stackebrandt E. Characterization of novel psychrophilic clostridia from an Antarctic microbial mat: description of Clostridium frigoris sp. nov., Clostridium lacusfryxellense sp. nov., Clostridium bowmanii sp. nov. and Clostridium psychrophilum sp. nov. and reclassification of Clostridium laramiense as Clostridium estertheticum subsp. laramiense subsp. nov. 2003 53 4 1019 1029 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.02554-0 12892121