The asynchronous growth and movement reconstruction of the early molting animals

Abstract

Epithelium is one of the basic types of animal tissue, in which tissue boundaries are the physical barriers to separate adjust cell clusters. However, tissue boundary in cellular level can hardly found in the fossil records. Here I focus on the growth and movement patterns of the early Ecdysozoa being through quantifying forces in cellular level of the epithelium of two worms from the early Cambrian and Ordovician period. The epithelium cells (might be but not necessarily represent the biological cell) separate adjust body ring of the early Ecdysozoa indicates a precise morphological patterning in cellular level has been established in the early Cambrian. The forces distribution patterns on the body ring suggest the boundary cells are contribute to maintain pressure gradient among rings which are the building blocks of the movement pattern of the worm. The active tension field of the worms plates though ontogenetic trajectory while epithelium cells are in the steady state indicate these molting animals employ asynchronous growth pattern of the epithelium.