Maximal totally complex submanifolds of $\mathbb{H}\mathbb{P}^n$:   homogeneity and normal holonomy
  We prove that a maximal totally complex submanifold $N^{2n}$ of the quaternionic projective space $\mathbb{H}\mathbb{P}^n$ ($n\geq 2$) is a parallel submanifold, provided one of the following conditions is satisfied: (1) $N$ is the orbit of a compact Lie group of isometries, (2) the restricted normal holonomy is a proper subgroup of ${\rm U}(n)$. 
Lucio Bedulli, Anna Gori, Fabio Podest\`a