Citation

Tilic E, Pauli B, Bartolomaeus T. J. Morphol. 2017; 278(6): 865-876.

Affiliation

Institute of Evolutionary Biology and Animal Ecology, Rheinische Friedrich Wilhelms Universität Bonn, An der Immenburg 1, Bonn, 53121, Germany.

Copyright

(Copyright © 2017, Wiley-Liss)

DOI

10.1002/jmor.20680

PMID

28370192

Abstract

Amphinomid species are since long known to cause urtication upon contact with the human skin. Since it has been reported that amphinomid chaetae are hollow, it has repeatedly been suggested that poison is injected upon epidermal contact. To test predictions for the structural correlate of such a stinging device we studied the structure and formation of chaetae in the fireworm Eurythoe complanata (Amphinomida). Neither the structure of the chaetae nor their formation and their position within the parapodium provide evidence for their function as hollow needles to inject poison. The chaetae even turned out to be not hollow, but containing calcareous depositions. The latter most likely cause artificial ruptures of delicate chitin lamellae in the inner of the chaeta when treated with acidic fixatives. Inorganic calcium compounds harden the chaetae and make them brittle so that they break easily. Additional information on the structure of the chaetal sac, the site of formation and the acicula do not contradict the position of the Amphinomida within Annelida as revealed by phylogenomic studies.

© 2017 Wiley Periodicals, Inc.

Language: en

Keywords

chaetogenesis; functional morphology; poison; polychaetes; transmission electron microscopy