Certain animals, primarily horses included in my analysis info (8)

'certain animals' is the definition.
(phylum including vertebrates)

'in my analysis info' is the wordplay.
'in' means one lot of letters goes inside another.
'my' becomes 'cor' (both are expressions of surprise).
'analysis' becomes 'h' (I am not sure about this - if you are sure you should believe this answer much more).
'info' becomes 'data' (data can mean information).
'cor' placed around 'h' is 'chor'.
'chor'+'data'='CHORDATA'

'primarily horses included' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.

Can you help me to learn more?