- Latin names of species are two word italicized names. The first word (which is
also the genus name) is capitalized; the second word (or trivial nomen) is lowercase. Examples include:
Homo sapiens, Tyrannosaurus rex, Cooperoceras texanum. If you abbreviate the species name,
you must use the capitalized first letter of the genus name, a period, a space, and the full trivial nomen, all in
italics: so H. sapiens, T. rex, and C. texanum. (NOTE: "T-Rex" or "T-rex" are just wrong!)
- Latin names of genera are single word italicized capitalized names: e.g., Homo,
- Other Latin names are capitalized but not in italics: e.g., Hominidae, Primates, Tyrannosauroidea,
Dinosauria, Cephalopoda, Mollusca. However, the vernacular (i.e., English) equivalents to these are ordinary
nouns rather than proper names, so treat them as such: hominid, primate, tyrannosauroid, dinosaur,
- Both the formal name of a geologic time unit and the rank itself are capitalized. Thus, it is
"Jurassic Period", "Early Cambrian Epoch", and "Paleozoic Era", not "Jurassic period", "early Cambrian epoch", and "Paleozoic era".
- Similarly, both the formal name and the word "formation" (or "group", "member", etc.), or the lithology, must be capitalized when
refering to formal stratigraphic units. Thus, it is the "Purslane Formation", "Tonto Group", and "Oriskany Sandstone",
not the "Purslane formation", "Tonto group", and "Oriskany sandstone".
- The prefixes in geologic time conform to the capitalization rules of metric prefixes more generally, so the lowercase "k" is
103 (kilo-, thousands), capital "M" is 106 (mega-, millions),
and capital "G" is 109 (giga-, billions). In refering to dates in the geologic past, use "a" (for "annum", year): thus,
18 ka would be 18,000 years before present; 65.5 Ma would be 65,500,000 years ago; and 4.56 Ga would be 4,560,000,000 years ago.
For durations, use "yr" (years) rather than "a". So 18 kyr would be any 18,000 year period in
Earth history, rather than specifically the last 18,000 years. For example, the Mesozoic Era (which
began at 251 Ma and ended 65.5 Ma) had a duration of 185.5 Myr.
- Numbers for isotopes of an element are in superscript prior the element abbreviation: e.g., 14C,
- Numbers for ionic charges are superscripts after the element or ion abbreviation: e.g., H+,
- Numbers for element abundance in a chemical formula are in subscript after the appropriate
element: e.g., CO2, H2SO4.