Anabarella

Anabarella
Temporal range: Lower Cambrian
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
(unranked): incertae sedis
Class: †Helcionelloida
Order: †Helcionelliformes
Family: †Helcionellidae
Genus: †Anabarella
Species
  • A. plana Vostokova, 1962
  • A. australis

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. 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.
  2. 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.
  3. ↑ 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.
  4. ↑ 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.
  5. ↑ 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.
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