Dinisia portugallica 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 : 223-224

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

Text-fig. 45a–e

H o l o t y p e. Designated here. S148216 (Torres Vedras sample 44; figured Text-fig. 45a–e ).

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.

PFN000484 (for new species).

P a r a t y p e. S148217 (Torres Vedras sample 44).

R e p o s i t o r y. Palaeobotanical Collections , Department of Palaeobiology, the Swedish Museum of Natural History, Stockholm, Sweden .

E t y m o l o g y. From Portugal where the fossils were discovered.

T y p e l o c a l i t y. Torres Vedras (NE of Forte de

Forca; 39°06′13″ N, 9°14′47″ W).

T y p e s t r a t u m a n d a g e. Lower member of the Almargem Formation; Early Cretaceous (late Barremianearly Aptian).

D i a g n o s i s. As for the genus.

D i m e n s i o n s. Length of anther: 0.75 mm; width of anther: 0.18 mm. Length of pollen grains: about 17–20 µm.

D e s c r i p t i o n a n d r e m a r k s. The anthers are dithecate and tetrasporangiate, narrowly elliptical in outline and broken near the base ( Text-fig. 45a ). Additional grains were also found in a pollen clump, possibly a coprolite, together with several other kinds of pollen. Pollen grains found in situ are small, about 17–20 µm long, elliptical to almost circular in equatorial outline and monocolpate. The colpus is short. The exine is semitectate-reticulate and columellate ( Text-fig. 45b–e ). The reticulum is homobrochate, with irregular vermiform muri of irregular width delimiting lumina of irregular shape and size. The detached showing the long colpus and the smooth surface of the foot layer; f) Holotype; fragment of stamen that yielded the pollen in (g–k); g) Cluster of pollen grains in proximal and distal views showing the distinctive equatorial reticulum and psilate distal and proximal regions; h–j) Distal views of pollen grains showing the equatorial reticulum and long colpus with verrucate colpus membrane; k) Proximal view of pollen showing the psilate polar region. Specimens, TV44 - S136671 (holotype; a–e), TV144 - S105002 (holotype; f–k). Scale bars 300 Μm (a, f), 10 Μm (g), 6 Μm (b, d, e, h–k), 6 Μm (b, d, e, h–k), 3 Μm (c).

columellae are long and scattered under the muri. The colpus has an indistinct margin and a colpus membrane covered by a fragmented reticulum ( Text-fig. 45b, e ). The inner surface of the anther wall is covered by densely spaced orbicules that are small, spherical and have an uneven surface (Textfig. 45c–e).

A f f i n i t y a n d o t h e r o c c u r r e n c e s. Similar grains have not been observed from other mesofossil floras.

Figures

Text-fig. 45. Scanning electron microscope (SEM) images of monocolpate pollen of Dinisia portugallica gen. et sp. nov. from a fragmentary stamen; Torres Vedras locality, Portugal. a) Holotype; stamen fragment showing elongated pollen sacs that yielded the pollen in this Text-figure; b) Two pollen grains showing poorly defined distal aperture (arrowhead) and distinctive vermiform reticulum forming luminae of variable shapes and sizes; note especially the irregularly and incomplete reticulum in the grain on the left; c) Reticulum showing smooth, vermiform muri attached to the smooth surface of the foot layer by long columellae; note that columellae often terminate segments of muri that are not closed; d, e) Pollen grains showing proximal surface (d), poorly defined distal aperture (e, arrowhead) and distinctive vermiform reticulum supported by long columellae; note dense covering of small, spherical orbicules on the inner surface of the anther wall. Specimen, TV44-S148216 (holotype). Scale bars 300 Μm (a), 6 Μm (b, d, e), 3 Μm (c).