Specifically on article titles (WP:NC#Animals, plants, and other organisms):
- The capitalization on the common names of species has been hotly debated in the past and remains unresolved. As a matter of truce both capitalized and non-capitalized (except for proper names) are acceptable, but a redirect should be created from the alternative form. Scientific names are always written in italics. The first name (genus) is capitalized, the second (species) is not. Examples: Homo sapiens, Tyrannosaurus rex, Velociraptor.
From Capitalization:
- A more controversial practice followed by some authors, though few if any style guides, treats the common names of some animal and plant species as proper nouns, and uses initial majuscules for them (e.g., Peregrine Falcon, Red Pine), while not capitalizing others (e.g., horse or person). This is most common for birds and fishes. Botanists generally reject the practice of capitalizing the common names of plants, though individual words of plant names may be capitalized by another rule (e.g., Italian stone pine). See the discussion of official common names under common name for an explanation.
From Common name:
- Botanists sometimes maintain official common names for plants, although this will vary greatly. Informally, botanists generally do not capitalize any common names; this can be seen as a sign of "professionalism" since the uninitiated may have difficulty in interpreting names such as "the hairy brome" for localities where the Hairy Brome (Bromus ramosus) is not the only member of the genus.
The Chicago Manual of Style, 15th Edition, addresses common names of plants and animals in 8.136. For the correct capitalization and spelling of common names of plants and animals, consult a dictionary or the authoritative guides to nomenclature, the ICBN and the ICZN, mentioned in 8.127. In any one work, a single source should be followed. In general, Chicago recommends capitalizing only proper nouns and adjectives, as in the following examples, which conform to Merriam-Webster's Collegiate Dictionary.Dutchman's-breeches, mayapple, jack-in-the-pulpit, rhesus monkey, Rocky Mountain sheep, Cooper's hawk.
From Wikipedia:Naming conventions (capitalization):
- Because credibility is a primary objective in the creation of any reference work, and because Wikipedia strives to become a leading (if not the) leading reference work in its genre, formality and an adherence to conventions widely used in the genre are critically important to credibility. See these recommended reference works for capitalization conventions: