Answer:
Approximately 700 species have been named. However, a
recent scientific review suggests that only about half
of these are based on fairly complete specimens that
can be shown to be unique and separate species. These
species are placed in about 300 valid dinosaur genera
(Stegosaurus, Diplodocus, etc.), although about 540
have been named. Recent estimates suggest that about
700 to 900 more dinosaur genera may remain to be
discovered.
Most dinosaur genera presently contain only one
species (for example, Deinonychus) but some have more
(for example, Iguanodon). Even if all of the roughly
700 published species are valid, their number is still
less than one-tenth the number of currently known
living bird species, less than one-fifth the number of
currently known mammal species, and less than
one-third the number of currently known spider species
