Figure 4. A in Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura

Figure 4. A, Pasternakevia podolica Selden & Drygant, 1987 from the late Silurian (Ludlow) of Zalissia, Ukraine. Specimen ISEA I - F/MP/3/1499/08, isolated opsithosoma with articulated microtergite of somite VII (arrowed). Image courtesy of Ewa Krzemin´ ska. Scale bar = 10 mm. B, undescribed chasmataspidid from the Lower Devonian (Emsian) of Siberia, Russia. Specimen PIN 5116-6, disarticulated buckler with microtergite of somite VII (arrowed) still firmly attached to its anterior margin. Image courtesy of Dave Marshall. Scale bar = 2 mm.