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- 1a. Sexual dimorphic species; females with apical part of corona invaginated and apical disc as large or larger than peristome.
- Go to 2
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1b. Sexes similar; periapical region not sunken as a marsupium; apical disc always much smaller than peristome. - Go to 6
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| 2a. Marsupia developed as five radial interradial pouches aborally in female. Pentechinus |
2b. Marsupia not developed as five radial interradial pouches aborally in female. Go to 3 |
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| 3a. Marsupia developed as deep interradial depressions aborally in female. Temnechinus |
3b. Entire adapical region sunken; no sunken interradial marsupia on corona of females. Go to 4 |
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4a. Test sculpture confined to just adapical interambulacral plates in marsupium
Hypsiechinus |
4b. Test sculpture well developed over all interambulacral plates.
Go to 5
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5a. Test ornament fine, with numerous pits in amongst the secondary tubercles of interambulacral plates.
Paradoxechinus |
5b. Test ornament of large pits at triple suture points.
Coptechinus |
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| 6a. Pits relatively large and transversely elongate. Pore zones more or less uniserial. Go to 7 |
6b. Pits small and punctiform, may be lost in adults. Pore zones in offset triads. Go to 10 |
