Table 1.
Comparison of morphological features of Megarachne with other large Carboniferous eurypterids. (✓, presence; ×, absence; ?, unknown.)
| features | Megarachne (Hünicken 1980) | Woodwardopterus (Kjellesvig-Waering 1959) | Mycterops (Cope 1886) | Cyrtoctenus (Størmer & Waterston 1968) | Hibbertopterus (Kjellesvig-Waering 1959) | Dunsopterus (Waterston 1968) | Vernonopterus (Waterston 1968) |
|---|---|---|---|---|---|---|---|
| carapace length (cm) | 17 | 15 | 5 | 35.5 | 38 | >10 | ? |
| linguoid ornament | scattered | scattered | dense | localized | scattered | scattered | minute |
| anteromedian carapace protrusion | ✓ | × | ? | ✓ | × | ? | ? |
| reniform lateral eyes, median eyes on tubercle | ✓ | ✓ | ✓ | ✓ | ✓ | ? | ? |
| enlarged first opisthosomal tergite | ✓ | ✓ | ✓ | × | × | ? | ? |
| enlarged second opisthosomal tergite | ✓ | ✓ | ? | × | × | ? | ? |
| thickened podomeres | ✓ | ✓ | ? | ✓ | ✓ | ✓ | ? |
| longitudinal grooves on podomeres | ✓ | ✓ | ? | ✓ | × | ✓ | ? |
| blade-like structures on podomeres | ✓ | ✓ | ? | ✓ | ✓ | ? | ? |
| coxal Laden | ✓ | ? | ? | × | ✓ | ? | ? |
| hastate telson with pair of carinae | ? | ✓ | ? | ✓ | ✓ | ? | ? |