"Caldococcus litoralis" were published as a representative of a novel genus, based on a significant difference of 14% in the GC Content with "Thermococcus celer", the only representative of "Thermococcus" known at the time the study was done in 1987. "C. litoralis" are irregularly shaped cocci, ranging from 0.7-2.1 µm in size. The species was isolated from hot volcanic vents at Hot Beach on the Kunashir Island, Japan It is a marine and extremely thermophilic archaebacterium capable of growth at 55-100 °C, with an optimum temperature of 88 °C. It is also capable of growth at pH values ranging from 5.9 -7.0 with an optimum at pH 6.4. Under optimal conditions, generation time is 44 minutes with 6 g of peptone per liter and elemental sulfur and an electron acceptor.