[CentOS] Q: respecting .ssh/id_rsa

While attempting to debug something else I ran across this:

ssh -vvv somehost
. . .
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/identity-cert type -1
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
. . .

However if I verify the key I see this:

ssh-keygen -l -f ~/.ssh/id_rsa.pub
4096 08:70:3b:92:4c:96:1c:6a:03:a4:ae:66:8d:9e:6c:93
/root/.ssh/id_rsa.pub (RSA)

Which seems ok to me. The permissions also seem ok:

.ssh]# ll
total 40
-rw-------. 1 root root  3863 Oct 11  2012 authorized_keys
-rw-------. 1 root root  3243 Aug  9  2012 id_rsa
-rw-r--r--. 1 root root   757 Aug  9  2012 id_rsa.pub
-rw-r--r--. 1 root root 11071 May  8 09:42 known_hosts

The password-less connections complete in any case but I am perplexed
as to what is the problem with the root identity key that ssh is
reporting.

Can anyone explain to me what this means?

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