The coiled Middle Ordovician cephalopod genera Trocholites and Curtoceras (Tarphyceratida) from Baltoscandia and north-central Europe
Author
Aubrechtová, Martina
3CAF4231-8787-4051-8D76-F983332517EE
Institute of Geology, Czech Academy of Sciences, Rozvojová 269, Prague, 16500, Czech Republic.
aubrechtova@gli.cas.cz
Author
Korn, Dieter
286CA4F3-7EBC-4AEF-A66A-B2508D001367
Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany.
dieter.korn@mfn.berlin
text
European Journal of Taxonomy
2025
2025-03-26
982
1
78
https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2843/12943
journal article
308947
10.5852/ejt.2025.982.2843
a1ffc010-9e7a-4cd4-a789-bc653917f76a
2118-9773
15096341
00EDB7C3-98B6-4FF6-93C3-2B2DCF8FA3A9
Table 2. Parameters and ratios used for the description of the tarphyceratid specimens studied herein.| Parameter [unit] | Abbrev. | Calculation |
|---|
| conch diameter [mm] | dm | – |
|---|
| whorl height [mm] | wh | – |
|---|
| whorl width [mm] | ww | – |
|---|
| umbilical width [mm] | uw | dm1−wh1−wh2 |
|---|
| apertural height [mm] | ah | dm1−dm2 |
|---|
| imprint zone [mm] | iz | wh 1 −ah |
|---|
| whorl expansion rate (outline) | WERdm | (dm / dm)2 1 2 |
|---|
| whorl expansion rate (apertural height) | WERah | [dm / (dm −ah)]2 1 1 |
|---|
| imprint zone rate | IZR | iz / wh |
|---|
| umbilical width index | UWI | uw / dm |
|---|
| conch width index | CWI | ww / dm |
|---|
| whorl width index | WWI | ww / wh |
|---|