BODY EXTENSION TYPES OF TETHYA WILHELMA: CELLULAR ORGANISATION AND THEIR LOCOMOTORY FUNCTION

Authors

  • MICHAEL NICKEL

Abstract

Like some other species of the genus, Tethya wilhelma shows locomotion. The maximum speed was measured with 2 mm·h-1. The rounded white body produces prominent extensions. Three types of extensions can be distinguished: type I produces buds (asexual reproduction), type II extensions (scout extensions) spread to all directions and may attach to the substrate and type III (guide extensions) play a role as guiding structures for movement. They develop from attached type II extensions, which extend at a maximum rate of 5 mm·h-1. The main cell type inside type II and III extensions are actinocytes, amoebocytes, multipolar and spherulous cells as well as pinacocytes. Actinocytes are the fastest cell types, displaying a measured speed of 400 µm·h-1. A preliminary hypothetical movement model for T. wilhelma is presented.

Downloads

Published

2018-05-23