Complex sentence: Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium, that is, an ellipsoidal shape, with all other minor planets and comets called "small Solar System bodies".
Split into simpler sentences: Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium and form an ellipsoidal shape. All other minor planets and comets are called "small Solar System bodies".