Turbellarian taxonomic database

Record # 17716
Raikova OI, Reuter M, Gustafsson MKS, Maule AG, Halton DW, Jondelius U (2004)
Evolution of the nervous system in Paraphanostoma (Acoela).
Zool Scr 33:71-88

Abstract / Notes

According to recent molecular studies, the Acoela are the earliest extant bilaterian group. Their nervous
system displays a striking variety of patterns. The aim of the present investigation was to study the
variability of the nervous system in a monophyletic group of the Acoela. Six species of Paraphanostoma were
chosen for the study. Using immunocytochemical methods and confocal scanning laser microscopy, the
immunoreactive patterns of serotonin (5-HT) and the neuropeptide GYIRFamide were described in detail. The
study has demonstrated that the brains in Paraphanostoma species, although diverse in detail, still follow
the same general pattern. 18S rDNA sequences were used to generate a hypothesis of the phylogeny within the
group. Characters of the nervous system revealed in this study were coded and analysed together with 18S rDNA
data. Several synapomorphies in the nervous system characters were identified. However, numerous parallelisms
in the nervous system evolution have occurred. Data obtained demonstrate that the genus Paraphanostoma is
closely related to Childia and should belong to the same family, Childiidae.

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