We introduce and motivate a notion of pseudo-arithmeticity, which possibly applies to all lattices in
PO
(
n
,
1
)
\operatorname {PO}(n,1)
with
n
>
3
n>3
. We further show that under an additional assumption (satisfied in all known cases), the covolumes of these lattices correspond to rational linear combinations of special values of
L
L
-functions.