Morphometric analysis of Cretaceous (Cenomanian) angiosperm woods from the Czech Republic

Abstract

The Cretaceous (Cenomanian) Peruc-Korycany Formation of the Czech Republic contains abundant charcoal including rare fragments of angiosperm wood. We conducted a SEM-analysis of thirty-nine angiosperm wood samples from four localities. Two types were recognized as follows: Morphotype 1 has narrow, densely packed vessels, very long scalariform perforation plates, opposite intervessel pits, and heterocellular rays of two sizes. It is herein named Icacinoxylon pecinovense sp. nov. Morphotype 2 has wide vessels, simple perforation plates, alternate intervessel pits, and short heterocellular rays and is assigned to Paraphyllanthoxylon marylandense Herendeen. Morphometric studies utilising Principal Component Analysis confirm this demarcation in morphospace, but despite large intrataxon variability does not support further splitting. Vessel diameter data suggest that Paraphyllanthoxylon was a large tree, challenging the idea that early angiosperms were small shrubs; the stature of Icacinoxylon is uncertain. Facies analysis suggests that both trees may have grown within riparian gallery forests under a subtropical climate, a finding consistent with calculations of Vulnerability Index.