The following rules over-ride any formatting that may exist in book and journal article titles.
Italicise: Latin binomens (e.g. Homo sapiens, Jasus edwardsii) should be italicised but common names (e.g. human, rock lobster) should not. If it is not possible to italicise then underline instead.
Captialise: Genus names should be capitalised but the species names should not (i.e. Genus species, Jasus edwardsii). Phylum, class, order, and family names should be capitalised (e.g. Chordata, Mammalia, Primates, Hominidae) but when used in a general way there is no need to do so. For example, Jasus edwardsii are crustaceans and so classed in the phylum Arthropoda. Humans are mammals, in the family Hominidae.