Table 2.

Definition of characters used for the construction of the morphological character matrix

	Character definition
1	Single type of secondary sensory cells (present = 1, absent = 0)
2	Secondary sensory cells with a single cilium (monociliary) (present = 1, absent = 0)
3	Secondary sensory cells with two cilia (biciliary) (present = 1, absent = 0)
4	Secondary sensory cells with more than two cilia (multiciliary) (present = 1, absent = 0)
5	Cilia in multiciliary sensory cells of same length (0) / different lengths (1)
6	Microvilli or stereovilli on sensory cells (present = 1, absent = 0)
7	Microvilli on monociliary sensory cells (present = 1, absent = 0)
8	Stereovilli on monociliary sensory cells (present = 1, absent = 0)
9	Cilium of monociliary sensory cell surrounded by a ring of microvilli (0) or cilium eccentric to microvilli (1)
10	Microvilli on multiciliary sensory cells (present = 1, absent = 0)
11	Cilia in multiciliary sensory cells in a single line (0) or in multiple lines (1)
12	Accessory secretory cells in coronal organ (present = 1, absent = 0)
13	Supporting cells form a wall or crest alongside the coronal organ (present = 1, absent = 0)
14	Electron dense granules in sensory cells (present = 1, absent = 0)
15	Width of coronal organ uniform along oral rim (0) or wider at certain areas (1)
16	Accessory centriole in sensory cells (present = 1, absent = 0)
17	Tentacles or flaps present (present = 1, absent = 0)
18	Tentacles simple (0) / branched (1)
19	Secondary sensory cells in continuous row (present = 1, absent = 0)