The Echinoid Directory

Key to genera of Stegasteridae

1a. Episternals biserially offset behind obviously aymmetric sternal plate.


1b. More or less symmetrical sternal plate followed by paired episternals.

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2a. Apical disc with supplementary gonopores in ocular plates II and IV.

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2b. No supplementary gonopores in ocular plates.

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3a. Aboral surface with prominent coarse major tubercles (yellow line).


3b. Aboral surface without major tubercles.


4a. Aboral pores rudimentary; ambulacral plates tall. Frontal groove well developed aborally and pinched at anterior.


4b. Aboral pores subpetaloid; ambulacral plates narrower. Frontal groove parallel-sided and less well-developed aborally.

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5a. Aboral surface with numerous coarse tubercles.


5b. Aboral surface without coarse tuberculation.