Eckhartia E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, 2019

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2019, The Early Cretaceous Mesofossil Flora Of Torres Vedras (Ne Of Forte Da Forca), Portugal: A Palaeofloristic Analysis Of An Early Angiosperm Community, Fossil Imprint 75 (2), pp. 153-257 : 208-209

Genus Eckhartia E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN gen. nov.

T y p e. Designated here. Eckhartia brevicolumella

E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN gen. et sp. nov.

P l a n t F o s s i l N a m e s R e g i s t r y N u m b e r.

PFN000471 (for new genus).

E t y m o l o g y. In honor of the German palynologist Eckhart Schrank in recognition of his important contribution to Cretaceous palynology.

D i a g n o s i s. Stamens with long anthers. Anther tetrasporangiate and dithecate. Pollen small, almost circular in equatorial outline, monocolpate. Colpus extending for the full length of the pollen grains. Exine semitectate-reticulate and columellate. Reticulum heterobrochate; identical on the proximal and distal faces; lumina isodiametric and polygonal to rounded. Muri smooth with flattened to slightly rounded profiles, supported by long distinct columellae. Colpus membrane granular. Colpus margin distinct with psilate regions around the end of the colpus. Orbicules large, dentate and densely distributed on inner surface of the anther wall.

C o m m e n t s o n t h e g e n u s. Dispersed monocolpate pollen grains with semitectate-reticulate and columellate pollen wall are typically assigned to the extinct pollen genus Retimonocolpites R.L.PIERCE, described from the Late Cretaceous of Minnesota, USA ( Pierce 1961). However, very few of the dispersed pollen grains assigned to the genus conform with the features of the type species, Retimonocolpites dividuus R.J.PIERCE , which is characterized by having “an aperture that almost encircles grain dividing it into two hemispheres; one polar and one equatorial plane of symmetry” ( Pierce 1961). The many species assigned to Retimonocolpites in the past undoubtedly belong to taxa of widely different systematic affinities. In the Torres Vedras mesofossil flora, as well as in many other Early Cretaceous mesofossil floras, pollen of this general kind have been found in different kinds of anthers or consistently on the stigmatic surfaces of flowers and fruits that are systematically distinct. In order not to obscure the systematic diversity of Early Cretaceous angiosperms we therefore establish several new genera for some of the pollen types that would otherwise be lumped together into a highly heterogeneous Retimonocolpites.