  A separating ($M-2$)-curve is a smooth geometrically irreducible real
projective curve $X$ such that $X(\mathbb{R})$ has $g-1$ connected components
and $X(\mathbb{C})\setminus X(\mathbb{R})$ is disconnected. Let $T_g$ be a
Teichm\"uller space of separating ($M-2$)-curves of genus $g$. We consider two
partitions of $T_g$, one by means of a concept of special type, the other one
by means of the separating gonality. We show that those two partitions are very
closely related to each other. As an application we obtain the existence of
real curves having isolated real linear systems $g^1_{g-1}$ for all $g\geq 4$.
