FIG. 1 in Upper Silurian and Devonian heterostracan pteraspidomorphs (Vertebrata) from Severnaya Zemlya (Russia): a preliminary report with biogeographical and biostratigraphical implications

FIG. 1. — Early Devonian agnathan vertebrate provinces (Lochkovian). Palaeogeographical reconstruction after Scotese & McKerrow (1990: fig. 13) and Cocks & Scotese (1991: fig. 3) for the Lochkovian. Palaeobiogeographical provinces after Blieck & Janvier (1999: fig. 9.14) and Young (1990: fig. 3). 1, North Atlantic Province (pteraspid-dominated faunas); 2, Rocky Mountain Province (protaspid- Allocryptaspis-Cardipeltis fauna); 3, Arctic Province (Ctenaspis-Benneviaspis and boreaspid-Gigantaspis faunas) (1 + 2 + 3 = Euramerica cephalaspid province of Young); 4, Angaran Province (amphiaspid fauna) = Siberia amphiaspid province of Young; 5, Tuvan Province (tannuaspid fauna) = Tuva tannuaspid province of Young; 6, South Chinese Province (galeaspid-yunnanolepid faunas) = South China galeaspid-yunnanolepid province of Young; 7, East Gondwana wuttagoonaspid-phyllolepid province of Young (this province is also defined by the pituriaspid agnathans in early Middle Devonian time: Young 1991). N.B.: Yunnanolepids, wuttagoonaspids and phyllolepids are placoderm taxa; all others are agnathan taxa. Abbreviations: KA, Kazakhstan; NWT, Northwest Territories of Canada; ORSC, Old Red Sandstone Continent; SC, South China; SI, Siberia; SV, Svalbard (Spitsbergen); SZ, Severnaya Zemlya.