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Earth Science cover
Estonian Journal of Earth Sciences
ISSN 1736-7557 (Electronic)
ISSN 1736-4728 (Print)
Impact Factor (2021): 0.811
Laminar shell structure of Antigonambonites planus (Pander, 1830) (Brachiopoda, Billingsellida); pp. 183–187

Anna Madison

The order Billingsellida comprises brachiopods with laminar and fibrous shells, however, the data on their microstructure are scanty and the taxonomic value of differences in their shell structure is uncertain. The shell structure of clitambonitidine Antigonambonites planus was found to be laminar, not fibrous as previously considered; possibly this shows that it belongs to the suborder Billingsellidina. The pseudopunctae in the secondary layer normally are formed by deflected laminae and lack taleolae. Possible remains of the tertiary prismatic layer are described and the diagenetic changes are appreciated.


Benedetto, J. L. 2009. Chaniella, a new lower Tremadocian (Ordovician) brachiopod from northwestern Argentina and its phylogenetic relationships within basal rhynchonelliforms. Paläontologische Zeitschrift, 83, 393–405.

Pander, C. H. 1830. Beiträge zur Geognosie des Russischen Reiches. St.-Petersburg, xx + 165 pp.

Popov, L. E., Vinn, O. & Nikitina, O. I. 2001. Brachiopods of the redefined family Tritoechiidae from the Ordovician of Kazakhstan and South Urals. Geobios, 32, 131–155.

Popov, L. E., Egerquist, E. & Holmer, L. E. 2007. Earliest ontogeny of Middle Ordovician rhynchonelliform brachio­pods (Clitambonitoidea and Polytoechioidea): implications for brachiopod phylogeny. Lethaia, 40, 85–96.

Öpik, A. 1934. Über Klitamboniten. Publications of the Geological Institution of the University of Tartu, 39, 1–240.

Topper, T. P., Harper, D. A. T. & Brock, G. A. 2013. Ancestral billingsellides and the evolution and phylogenetic relation­ships of early rhynchonelliform brachiopods. Journal of Systematic Palaeontology, 11, 821–833.

Vinn, O. 2001. A new subspecies of the clitambonitidine brachiopod Estlandia catellatus from the Middle Ordovician of Osmussaar Island, Estonia. Proceedings of the Estonian Academy of Sciences, Geology, 50, 86–94.

Vinn, O. & Rubel, M. 2000. The spondylium and related structures in the Clitambonitidine brachiopods. Journal of Paleontology, 74, 439–443.<0439:TSARSI>2.0.CO;2

Williams, A. 1968. Evolution of the shell structure of articulate brachiopods. Special Papers in Palaeontology, 2, 1–55.

Williams, A. 1970. Origin of laminar-shelled articulate brachiopods. Lethaia, 3, 329–342.

Williams, A. & Cusack, M. 2007. Chemicostructural diversity of the brachiopod shell. In Treatise on Invertebrate Paleontology, Pt. H: Brachiopoda Revised. Vol. 6: Supplement (Selden, P. A., ed.), pp. 2396–2521. Boulder, Colorado.

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