Can someone answer the following question: Is there any classification of maximal proper Zariski-closed real subgroups of $SO(p,q)$ which are not parabolic, and satisfy the following conditions:

they have rank at least the rank of $SO(p) \times SO(q)$ .

they should act irreducibly on the natural representation of $SO(p,q)$, i.e. on $\mathbb{R}^{p,q}$.

Thanks.