Figure 53 in Atlas of Myriapod Biogeography. I. Indigenous Ordinal and Supra-Ordinal Distributions in the Diplopoda: Perspectives on Taxon Origins and Ages, and a Hypothesis on the Origin and Early Evolution of the Class

Figure 53. Land areas in the Mid-Cambrian Period, Paleozoic Era, adapted from the website of Ron Blakey, Geology Dept., Northern Arizona University, Flagstaff, Arizona, USA (http://jan.ucc.nau.edu/~ rcb7/RCB.html), symbols as in Fig. 52. The bold arrow represents emergence of the original ancestor from the Iapetus Ocean onto the Avalonia terrane that is still attached to Gondwana I around 524 ma, and the short, lighter arrows show initial dispersions through Avalonia and onto Gondwana I proper; at this time, other land masses and the rest of Gondwana I were devoid of diplopods. A, Avalonia terrane; Af, "proto-Africa" region of Gondwana I; B, Baltica; GI, Gondwana I; K, Kazakhstania; L, Laurentia; S, Siberia; SA, "proto-South America" region of Gondwana I.