Credneria Zenker (Platanaceae): an extinct endemic plane tree from the Upper Cretaceous (Santonian) of Central Germany and its ancient environment
(English)Manuscript (preprint) (Other academic)
Leaves of the Late Cretaceous angiosperm Credneria from its type locality in the Subhercynian Cretaceous Basin were investigated with morphological and statistical methods. Quantitative analysis of the morphological variability of the leaves suggests that the previously distinguished morphotypes Ia and Ib constitute sun and shade leaves of a single species, Credneria denticulata. Qualitative evaluation of the leaves reveals a combination of characters that link Credneria with the Platanaceae. Most determinative for this affiliation were an actinodromous venation, the presence of several pairs of suprabasal veins at the leaf base, spinose teeth and an inflated petiole base that originally enclosed the axillary bud. More than 50 species of Credneria have been described from localities outside the Subhercynian Cretaceous Basin. Although some of these species resemble the leaves from the type locality superficially, many of the determinative characters differ in detail or are absent. Many of these fossils were later assigned to Platanus. In the context of the pronounced provincialism of many taxa during the Cretaceous, it is likely that Credneria was endemic to Central Europe. Sedimentological features of the host deposit point to an accumulation of Credneria leaves in a tidal-influenced coastal landscape close to a shallow sea with cyclic transgressions and regressions. Credneria most likely inhabited a disturbed, early successional environment in a coastal delta floodplain. The occurrence of fossil tropical soils (hematitic oxisols) points to a warm and humid climate that probably was seasonal.
Credneria, Platanaceae, leaf morphology, morphological variability, quantitative analysis, character combination, sedimentary environment, Cretaceous plant ecology
Research subject Plant Ecology
IdentifiersURN: urn:nbn:se:su:diva-62711OAI: oai:DiVA.org:su-62711DiVA: diva2:444090