Valve Morphogenesis in Amphitetras antediluviana Ehrenberg

Mary A. Tiffany, Bonnie L. Hurwitz

Research output: Chapter in Book/Report/Conference proceedingChapter


Amphitetras antediluviana is a marine chain-forming epiphytic diatom. Here we provide the first study of its valve and girdle band development. Each valve has four ocelli at the corners with gently curving sides and a circular elevation in the center. In early valves, we observed a circular to oval annulus with radiating costae (virgae) that occasionally bifurcate before forming the ocellus. The costae interconnect by crossbars (vimines) to form areolae. Virgae at the periphery of the valve bend in the direction of the ocelli, eventually fusing to produce their rims. Once the rim is fully enclosed, small pores start to form centripetally until they meet at the center. Two types of cribra develop within the areolae. The most common form consists of small poroids supported by tiny struts on the edge of the areola. The struts repeatedly bifurcate to produce a mesh of poroids. The other type of cribrum begins with sturdier struts that broaden to become spathulate, adding flattened structures as they expand, leaving slits instead of pores. Finally a marginal flange is added. Future research is needed to determine how this species forms two very different types of cribra, possibly using transmission electron microscopy of dividing cells.

Original languageEnglish (US)
Title of host publicationDiatom Morphogenesis
Number of pages12
ISBN (Electronic)9781119488170
ISBN (Print)9781119487951
StatePublished - Jan 1 2021


  • Amphitetras antediluviana
  • Southern California
  • alternate cribra, girdle bands
  • cribrum development
  • ocellus
  • valve development in diatoms

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Biochemistry, Genetics and Molecular Biology


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