Burgeria 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 : 200-201

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

T y p e. Designated here. Burgeria striata 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.

PFN000467 (for new genus).

E t y m o l o g y. In honor of the American botanist William C. Burger in recognition of his contributions to the study of angiosperm evolution.

D i a g n o s i s. Pollen grains of medium size, broadly ellipsoidal to subcircular in equatorial outline, monocolpate. Colpus in fully developed grains almost as long as longest axis, broad; colpus in smaller (aborted?) grains about half the length of the longest axis. Exine tectate-punctate and columellate with short columellae and a thin foot layer. Surface of tectum finely striate. Orbicules spherical, punctate with finely striate surface.

C o m m e n t s o n t h e g e n u s. The pollen grains of

Burgeria are among the largest angiosperm grains observed in the Torres Vedras flora. In their tectate-perforate exine and long colpus, pollen of Burgeria is similar to grains of Lethomasites fossulatus J.V.WARD, J.A.DOYLE et HOTTON described from the Early Cretaceous Potomac Group ( Ward et al. 1989). However, L. fossulatus is much larger (92–127 µm), the exine stratification is granular rather than columellate, and the grains have larger perforations (foveolae/ fossulae) that expose the infratectal granules. Resolution of the SEM images of L. fossulatus is good, but it is not clear whether there are fine striations between the perforations as in Burgeria . Pollen grains of Burgeria striata are also similar to pollen of Foveomonocolpites ravnii E.SCHRANK described from the Early Cretaceous of Israel ( Schrank 2017). Like Burgeria , pollen of F. ravnii has a tectate-columellate and finely perforate exine, but the grains are larger (42–69 µm) and the surface between the perforations is smooth.

Among extant angiosperms comparable monocolpate, tectate-perforate and finely striate pollen grains have been described for the two species of Gymnotheca DECNE. , G. chinensis DECNE. and G. involucrata C.PEI , in the piperalean family Saururaceae ( Smith and Stockey 2007) . Pollen of Gymnotheca is also similar to that of Burgeria in exine stratification with short columellae and a thin foot layer. Gymnotheca pollen also has a long, broad colpus with a granular colpus membrane similar to that of Burgeria . However, pollen grains of Saururaceae are tiny compared to those of Burgeria ( Smith and Stockey 2007, Grímsson et al. 2017). Although probably systematically close to the family Saururaceae , fossil Burgeria pollen cannot be included securely in any extant genus or within the family. Burgeria is assigned here broadly to the Piperales . The presence of orbicules also supports a probable relationship to Piperales ( Gonzáles et al. 2001).