New SEM observations of keriothecal walls: Implications for the evolution of fusulinida

Journal article
(Review article)

Publication Details

Author(s): Vachard D, Munnecke A, Servais T, Munnecke A, Munnecke A
Journal: Journal of Foraminiferal Research
Publisher: Cushman Foundation for Foraminiferal Research
Publication year: 2004
Volume: 34
Journal issue: 3
Pages range: 232-242
ISSN: 0096-1191


This study presents new scanning electron microscopy (SEM) observations of Paleozoic foraminifera. It focuses especially on the wall of three Fusulinida, Sakmarella moelleri, Paraskinnerella skinneri, and Taiyuanella furoni, that belong to the Schwagerinoidea, which are fusulinids with keriothecal test walls. In addition, Eostaffella sp. is investigated as an example of the microstructure of the microgranular imperforate tectum. The fillings of the keriothecal alveoles of Sakmarella, Paraskinnerella, and Taiyuanella yield diverse, characteristic flower-like structures that indicate a gradual evolution of the microstucture of the tests. Sakmarella and Paraskinnerella have flowers with a narrow center, and Taiyuanella has a larger center. The true keriothecal structure, described, for example, in Triticites, is distinguished from these structures by simply filled alveoles. The term "anthotheca" is introduced for the structure with narrow-centered flowers. It can be distinguished from the large-centered flower structure identified as Zhuang's (1989) stalactotheca. Following a literature review of previous work on keriothecal structures, several morphofunctional hypotheses are discussed, including the housing of symbiotic algae or cyanobacteria, which leads to the new interpretation that the flowers of the antho- and stalactothecal structures are induced by algal endosymbionts. In addition, we discuss the monophyly of keriothecal fusulinids. The transition from diaphanothecal to keriothecal forms recognized since Thompson (1964) is reinterpreted in terms of relationships with symbiotic algae or cyanobacteria. The Schwagerinoidea constitute an important group in understanding the evolution of larger foraminifera in the late Paleozoic.

FAU Authors / FAU Editors

Munnecke, Axel Prof. Dr.
Lehrstuhl für Paläoumwelt
Munnecke, Axel Prof. Dr.
Naturwissenschaftliche Fakultät
Munnecke, Axel Prof. Dr.
Professur für Paläontologie (Schwerpunkt Faziesanalyse)

External institutions with authors

LILLE 1 University - Science and Technology

How to cite

Vachard, D., Munnecke, A., Servais, T., Munnecke, A., & Munnecke, A. (2004). New SEM observations of keriothecal walls: Implications for the evolution of fusulinida. Journal of Foraminiferal Research, 34(3), 232-242.

Vachard, Daniel, et al. "New SEM observations of keriothecal walls: Implications for the evolution of fusulinida." Journal of Foraminiferal Research 34.3 (2004): 232-242.


Last updated on 2018-01-11 at 20:50