PhD thesis
PhD thesis
PhD thesis
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Short abstract<br />
This <strong>thesis</strong> deals with selected aspects of brachiopod ontogeny. By use of<br />
immunocytochemistry combined with confocal laserscanning microscopy and<br />
3D reconstruction software the development of the nervous and muscular<br />
system of rhynchonelliform and craniiform brachiopod larvae is described. The<br />
expression patterns of the developmental homeobox containing genes TtrNot<br />
and TtrCdx are described by use of whole mount in situ hybridization. The main<br />
results are: (1) The larval myoanatomy of rhynchonelliform brachiopod larvae is<br />
similar despite gross morphological differences in their outer morphology. (2) The<br />
rhynchonelliform and craniiform brachiopod larvae show a serotonergic nervous<br />
system comprising eight or four flask-shaped cells in the apical organ. An apical<br />
organ comprising flask-shaped cells might be a morphological apomorphy of<br />
Lophotrochozoa. (3) The expression pattern of the TtrNot gene in larvae of<br />
Terebratalia transversa suggests an ancestral role of this gene in gastrulation<br />
and ectoderm specification in Brachiopoda. The expression pattern on TtrCdx<br />
suggests an ancestral role of this gene in gastrulation and the formation of<br />
posterior ectodermal tissue in Brachiopoda.