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. |
 |
 |
|
2a. Apical disc with supplementary gonopores in ocular plates II and IV. |
2b. No supplementary gonopores in ocular plates. |
 |
 |
|
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. |
 |
 |
|
5a. Aboral surface with numerous coarse tubercles. |
5b. Aboral surface without coarse tuberculation. |