Let $F$ be a commutative field and $n\geqslant 2$ be an integer. It is well known that the maximal anisotropic mod center tori in $G={\rm GL}(n,F)$ are of the form $T = {\rm Res}_{E/F}\; {\mathbb G}_m$,for some degree $n$ separable field extension $E/F$,  where ${\rm Res}$ denotes Weil's restriction of scalar and where ${\mathbb G}_m$ denotes the $1$-dimensional split torus.

 Such a torus $T$ embeds in $G$ in the following way. One identifies $G$ with ${\rm Aut}_F\; (E)$ and make $E^{\times} =T(F)$ acts on $E$ by multiplication.

 One says that a torus is elliptic if it is not contained in any proper parabolic subgroup of $G$. The tori $T$ described above are  elliptic.

 My question is :

 > What are the tori of $G$ that are simultaneously elliptic and anisotropic?