, Volume 100, Issue 12, pp 1187–1191 | Cite as

Larval anatomy of the pterobranch Cephalodiscus gracilis supports secondarily derived sessility concordant with molecular phylogenies

  • Thomas StachEmail author
Short Communication


Pterobranchs have been interpreted as “missing links” combining primitive invertebrate features with advanced vertebrate-like characteristics. The first detailed morphological description of an ontogenetic stage of a pterobranch, based on digital 3D-reconstruction at electron microscopic resolution, reveals a triploblastic animal with monociliated epithelia, an extensive coelomic cavity, a through gut with an asymmetrically developed gill slit but no signs of planktonic specializations, such as ciliated bands. Therefore, this crawling larva supports the hypothesis proposed in previous molecular phylogenetic studies that pterobranchs could be derived within enteropneusts rather than being “missing links”.


Deuterostome evolution Hemichordate Dipleurula 



I thank Katrin Braun, Ronny Vogler, and Benjamin Hebel for their help with the 3D-reconstruction. Funding of the DFG and BIOS is gratefully acknowledged.

Supplementary material

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Humboldt-Universität zu Berlin, Comparative ZoologyBerlinGermany

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