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protoseptum septum

Summary

pl. Protosepta a member of the set of six first septa in rugosan and scleractinian corallites. Using 12-hour clock face as an approximate reference template, rugosans insert a single cardinal septum (symbol C) at '6 o'clock', a single counter septum (K) at '12', two counter-lateral septa (KL) on either side of K at '2' and '10' respectively, and two alar septa (A) on either side of C at '4' and '8' respectively. These terms are not used for scleractinians, but the protosepta at '6' and '12' are the Directive Septa, and may be larger than any other septa and diametrically joined. In both coral groups, the '6-and-12' pair may align with a median columellar plate and often confer a partly bilateral symmetry on some corallites or taxa. In many taxa, the identity of the protosepta is often lost during subsequent development, but in rugosans, the cardinal septum is often associated with a cardinal fossula. Distinct protosepta do not appear to have been recognized in tabulate corals. See also Cardinal fossula, Septal cycle, Septal insertion, Septa size order.

Orthography

Not yet available.

This term is a sub-term of septum.

Description

Not yet available.

This version was contributed by Ken Johnson on 22-Apr-2008 14:35.

Page authors include: Ken Johnson. Please contact the editor if you would like to contribute to the definition of this term.
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