Skip to main content

Table 1 Features of the organization of the serotonin-like immunoreactive nervous system in ciliated larvae of phoronids and in some protostomian and deuterostomian organisms

From: Development and organization of the larval nervous system in Phoronopsis harmeri: new insights into phoronid phylogeny

Feature Phoronida Protostomia Deuterostomia
Nemertea, Polychaeta, Mollusks Hemichordata, Echinodermata
[16, 18, 19, 2731] herein [4552] [4144, 53]
location where the first perikarya appear always on the anterior pole of the embryo mostly on the anterior pole, but on the posterior pole of the embryo in some species always on the anterior pole of the embryo
location where the first neurites appear neurites under the postoral ciliated band neurites under the preoral ciliated band neurites under the postoral ciliated band
number of perikarya in the apical organ many few many
(more than 50) (2-12 perikarya) (more than 30)
organization of the neurite bundle underlying the postoral ciliated band:    
  1) present/absent 1) + 1)― (in the most of protostomia larvae) + [46] 1) +
  2) presence of the connection with apical organ 2) + 2) ― (even if neurite bundle exists) 2) +
  3) presence of perikarya among neurites 3) + [herein] ― [28, 30, 31] 3) ― (even if neurite bundle exists) 3) +
presence of the telotroch nerve ring + +
presence of the ventral nerve cord in early development + +
  1. “ + ” indicates the presence of the feature; “―” indicates its absence.