At least five animal phyla exhibit spiralian development, which is characterized by striking
similarities in the geometry of the early cleavage pattern and the fate map of the blastula …

Spiralian embryogenesis is deeply conserved and seems to have been in place in the last
common ancestor of the large assemblage of protostome phyla known as the …

an overview as broad as possible. The authors, all renowned experts in the field, have put
particular effort into presenting the current state of knowledge as comprehensively as …

Abstract Nielsen, C. 2010. Some aspects of spiralian development.—Acta Zoologica
(Stockholm) 91: 20–28 Spiralian development is not only a characteristic early cleavage …

The super-phylum Lophotrochozoa contains the plurality of extant animal phyla and exhibits
a corresponding diversity of adult body plans. Moreover, in contrast to Ecdysozoa and …

Recent molecular evidence suggests the turbellarian Platyhelminthes may represent the
extant basal members of the Spiralia and therefore probably exhibit ancient features of the …

The embryology of sipunculans, entoprocts, nemertines, platyhelminths (excluding
acoelomorphs), rotifers, ectoprocts, phoronids, brachiopods, echinoderms and …

The Spiralia is a clade of protostome invertebrate phyla that share a highly conserved mode
of early development. Spiralian development is characterized by regularities in the …

Recent progress in reconstructing animal relationships enables us to draw a better picture of
the evolution of important characters such as organ systems and developmental processes …

It has been proposed that animals have a pattern of developmental evolution resembling an
hourglass because the most conserved development stage—often called the phylotypic …