2012] Acropora sirikitiae | Queen Sirikit.

2012] Germinated this way: New Genus of.

2012] Transient yellow colouration of.

These results are more compatible with a deuterostomic rather than protostomic (blastopore forms the mouth) or amphistomic (mouth and anus are formed simultaneously) mode of development in the last common bilaterian ancestor. caudatus follows strictly a deuterostomic pattern. Thereby, gastrulation in the conservatively evolving protostome P. We show that the blastopore gives rise to the anus at the vegetal pole and that the hindgut markers brachyury and caudal are expressed in the blastopore and anus, whereas the foregut markers foxA and goosecoid are expressed in the mouth in the animal hemisphere. Here, we characterize gastrulation and the embryonic expression of genes involved in bilaterian foregut and hindgut patterning in Priapulus caudatus.

Priapulids have a conservative morphology, an abundant Cambrian fossil record, and a phylogenetic position that make them a key group in understanding protostome evolution.

The blastopore fate of the bilaterian ancestor plays a crucial role in understanding the transition from radial to bilateral symmetric organisms. This variability, combined with an absence of information from key taxa, hampers the reconstruction of the ancestral developmental mode of the Protostomia and the Bilateria. In deuterostomes, the blastopore forms the anus, but its fate in protostome groups is variable. The fate of the blastopore during development in the bilaterian ancestor is currently not well understood.

Definition blastopore