A major class of sterane biomarkers found in petroleum hydrocarbons. The C30 Dinosteranes (e.g. 4?, 23, 24 trimethylcholestane) probably originate from dinoflagellate sterols. Dinosteranes are used as indicators of marine rocks and are related to oil with marine dinoflagellate input. The non-marine dinoflagellate species are also known to provide geologic age information as dinoflagellates are largely restricted to Triassic and younger samples.