Sprecher
Beschreibung
The early diversification of angiosperms has been documented by diverse Cretaceous fossil flowers, most of which are preserved as three-dimensional charcoalifications. Here, we describe Bohemiantha tricarpellata gen. et sp. nov., a new charcoalified flower from the Late Cretaceous of southern Bohemia, Czech Republic. We documented internal and external floral morphology of several specimens using scanning electron microscopy (SEM) and high-resolution X-ray computed tomography (HRXCT). The phylogenetic placement was evaluated through a two-step approach, first using an angiosperm-wide dataset followed by an analysis within the order Ericales. Bohemiantha tricarpellata exhibits a pentamerous perianth differentiated into calyx and corolla. The calyx is actinomorphic, with five free sepals arranged in a single whorl with quincuncial aestivation. The corolla is only partially preserved, but petals are apparently united at least at the very base. The gynoecium consists of three united carpels and is further characterized by a mostly superior ovary with a raised nectariferous ring, a robust style, and three short commissural stigma lobes. Numerous anatropous ovules are inserted on axile placentae. The androecium is unknown. Dispersed pollen grains are prolate and triaperturate. Detailed morphological comparison with extant taxa, along with explicit phylogenetic analyses, strongly support the placement of B. tricarpellata within the asterid order Ericales. We found strongest support for a potential relationship with Fouquieriaceae and Clethraceae, respectively. However, support values are generally weak and relationships with other ericalean lineages such as Diapensiaceae and Marcgraviaceae are possible.