Anabarella
| Anabarella Temporal range: Lower Cambrian | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| (unranked): | incertae sedis |
| Class: | †Helcionelloida |
| Order: | †Helcionelliformes |
| Family: | †Helcionellidae |
| Genus: | †Anabarella |
| Species | |
| |
Anabarella is a species of bilaterally-flattened monoplacophoran mollusc,[1] with a morphological similarity to the rostroconchs.[2] Its shell preserves evidence of three mineralogical textures on its outer surface: it is polygonal near the crest of the shell, subsequently changing to both spiny and stepwise.[2] Its internal microstructure is calcitic and semi-nacreous.[3] Its name reflects its provenance from Anabar, Siberia.[2] It has been interpreted as ancestral to the rostroconchs,[4] and has been aligned to the Helcionellidae.[1]
The genus is closely related to Watsonella, with which it bears many morphological similarities,[2] including a laminar internal shell microstructure said to connect it with the early bivalves Fordilla and Pojetaia.[5]
References
- 1 2 Gubanov, A.; Skovsted, C.; Peel, J. (2004). "Anabarella australis (Mollusca, Helcionelloida) from the Lower Cambrian of Greenland". Geobios. 37 (6): 719–724. doi:10.1016/j.geobios.2003.05.009.
- 1 2 3 4 Kouchinsky, A. V. (1999). "Shell microstructures of the Early Cambrian Anabarella and Watsonella as new evidence on the origin of the Rostroconchia". Lethaia. 32 (2): 173–180. doi:10.1111/j.1502-3931.1999.tb00537.x.
- ↑ Vendrasco, Michael J.; Porter, Susannah M.; Kouchinsky, Artem; Li, Guoxiang; Fernandez, Christine Z. (2010). "New data on molluscs and their shell microstructures from the Middle Cambrian Gowers Formation, Australia". Palaeontology. 53 (1): 97–135. doi:10.1111/j.1475-4983.2009.00922.x.
- ↑ Peel, J. S. (1991). "Functional Morphology of the Class Helcionelloida Nov., and the Early Evolution of the Mollusca". In Simonetta, A. M.; Conway Morris, S. The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge U. Pr. pp. 157–177. ISBN 978-0-521-40242-2.
- ↑ Vendrasco, M.J.; Checa, A.G.; Kouchinsky, A.V. (2011). "Shell microstructure of the early bivalve Pojetaia and the independent origin of nacre within the Mollusca". Palaeontology: no–no. doi:10.1111/j.1475-4983.2011.01056.x.