Obolellata

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title: "Obolellata" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["prehistoric-brachiopod-orders", "cambrian-first-appearances", "cambrian-extinctions"] description: "Extinct class of brachiopods" topic_path: "general/prehistoric-brachiopod-orders" source: "https://en.wikipedia.org/wiki/Obolellata" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct class of brachiopods ::

| fossil_range = | taxon = Obolellata | subdivision_ranks = Orders & families | subdivision = {{Nested taxon list | Obolellida | Rowell, 1965 | {{linked taxon list | Obolellidae | | Trematobolidae | | incomplete=yes}} | Naukatida | Popov and Tikonov 1990 | {{linked taxon list | Tomteluvidae | Streng et al 2016 | incomplete=yes}}

The Obolellata are a class of Rhynchonelliform brachiopods with two orders, Obolellida and Naukatida. They are essentially restricted to the lower-middle Cambrian.

Obolellida

Obolellida is a small, extinct order of inarticulate brachiopods that existed from the early to middle Cambrian period. The relationship of the Obolellida with other inarticulates is unclear, and were previously grouped together with the Siphonotretacea, before being given their own order.

One representative, Mummpikia, has been linked to the origin of calcitic shelled brachiopods more generally, hinting that obolellids may be paraphyletic.

Trematobolidae includes taxa such as Alisina, whose soft-part anatomy is partly known.

Anatomy

The shell is typically impunctate, biconvex, and oval or subcircular in shape. They are like other inarticulates in that, as with the lingulids, the shell has no hinge, at least in the earliest examples. It is thought they may have used a hydraulic mechanism. However they later seem to develop a primitive articulation, in which some used a levator mechanism for opening the shell. At the posterior is a ventral valve with a defined flat-shelf. The pedicle opening can be positioned at various positions.

Naukatida

Some of these are coral-like creatures.

References

Key reference:

References

1. Streng, M., A. D. Butler, J. S. Peel, R. J. Garwood, and J.-B. Caron. 2016. A new family of Cambrian rhynchonelliformean brachiopods (Order Naukatida) with an aberrant coral-like morphology. Palaeontology, 59:269–293.
2. Balthasar, U. (2008). Mummpikia gen. nov. and the origin of calcitic-shelled brachiopods. Palaeontology 51, 263–279.
3. "Paleos, Order Obolellida".
4. Lipps, Jere H.; Signor, Philip W. (January 1, 1992). ''Origin and Early Evolution of the Metazoa''. Springer. {{ISBN. 0-306-44067-9. Page 417.
5. "McGraw-Hill AccessScience, Obolellida".

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