Dinosterane is a steroidal alkane, also known as 4α,23,24-trimethylcholestane. It is used in geochemistry as a biomarker, interpreted as an indication of

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

presence due to its derivative

dinosterol Dinosterol is a type of steroid produced by several genera of dinoflagellates. It is a 4α-methyl sterol (4α,23,24-trimethyl-5α-cholest-22E-en-3β-ol), a derivative of dinosterane, rarely found in other classes of protists. This sterol and ot ...

high occurrence in extant dinoflagellate species and its rarity in other taxa, although it has been shown to be produced by a single species of marine

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

as well.

History of use as a biomarker

A 1984 study was conducted which established the dinoflagellate origin for dinosterane based on distributions of modern dinoflagellates and dinosterane abundance in sediment. In 1993, dinosteranes were discovered in a section of the Bristol Trough that was dated to the

Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...

Age. Due to the co-deposition of these dinosteranes with dinoflagellate cysts and comparison of microfossil abundance with hydrocarbon abundance, the dinosterane was associated with marine dinoflagellates. This was the first stratigraphic evidence for

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

dinoflagellates. In 1998, dinosteranes were found in high relative abundance in samples from the Lükati Formation, which were collected from the Kopli quarry in Estonia. This evidence was used to place the origin of dinoflagellates as early as the Early

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

, much earlier than the Bristol Trough studies had been able to.

Characterisation

Dinosterane's mass spectrum shows a highly increased abundance of the ''m/z'' = 98 ion compared to 24-ethyl-4α-methylcholestane, which is likely due to preferential cleavage of the C-22,23 bond.

References

{{reflist Hydrocarbons Cholestanes Biomarkers