Morphological variation and distribution of the Tournaisian (Early Mississippian) miospore Waltzispora lanzonii DAEMON 1974

Mississippian strata of the Amazonas Basin, northern Brazil, contain abundant and diverse assemblages of miospores, many of considerable stratigraphic importance. These include an acavate trilete species - Waltzispora lanzonii - which is the subject of the present account. Based on numerous specimens from the Tournaisian ( Lower Mississippian) Oriximina Formation, the morphology of the more typical and also the relatively rare, aberrant representatives of W. lanzonii is illustrated and described in detail. Current and previously published data indicate that the species is restricted palaeogeographically to north-northwest Gondwana; i.e., incorporating parts of present-day northern Brazil, Peru, and the Sahara region of Algeria and Libya. Chronostratigraphically, W. lanzonii is characteristic of and perhaps entirely confined to Tournaisian strata, although the possibility exists that it may extend slightly higher, into the Visean. However, rare occurrences of the species in upper Visean strata are considered to be a probable consequence of reworking.