Table 1 Comparative difference in size, shape, and spines in five species of Echinoderes of which muscle architecture was investigated
|  | Trunk length (μm) | Outline | Middorsal spines | Tergal extensions |
|---|---|---|---|---|
E. dujardinii | 350 | Barrel shaped | 5 short | Short |
E. hispanicus | 300 | Elongated | 3 long | Short |
E. horni | 270 | Elongated | None | Short |
E. spinifurca | 270 | Elongated | 5 long | Long |
Echinoderes sp. | 270 | Bulbous anterior end | 1 short | Short |