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Updated: Jul 12, 2026
08:09
Microfocus X-ray CT (microCT) Imaging of Actinia equina (Cnidaria), Harmothoe sp. (Annelida), and Xenoturbella japonica (Xenacoelomorpha)
Published on: August 6, 2019
Summary
Tentaculites shells possess a unique calcite structure, featuring ridge and groove patterns and a cross-bladed fabric. This microstructure suggests a potential evolutionary link between Tentaculites, brachiopods, and phoronids.
Area of Science:
- Paleontology
- Microscopy
- Biomineralization
Background:
- Tentaculites are an enigmatic group of extinct marine invertebrates.
- Their shell microstructure and evolutionary relationships remain poorly understood.
Purpose of the Study:
- To investigate the shell microstructure of Tentaculites using advanced microscopy.
- To determine potential affinities of Tentaculites with other fossil groups based on shell structure.
Main Methods:
- Transmission electron microscopy (TEM) was employed to examine fractured shell surfaces.
- Detailed analysis of the calcite fabric and structural elements was performed.
Main Results:
- Tentaculites shells are composed of calcite.
- A distinctive ridge and groove structure was identified.
- A cross-bladed fabric, previously observed only in articulate brachiopods, was revealed.
Conclusions:
- The unique shell microstructure of Tentaculites, particularly the cross-bladed fabric, suggests a possible evolutionary relationship with articulate brachiopods.
- Alternatively, a relationship with phoronids is also considered based on the findings.
- Further research is needed to fully elucidate the phylogenetic position of Tentaculites.
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