Juhaszia 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 : 221

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

Text-fig. 44a–e

H o l o t y p e. Designated here. S136671 (Torres Vedras sample 44; figured Text-fig. 44a–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.

PFN000482 (for new species).

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 pollen grains: about 23–

24 µm.

D e s c r i p t i o n a n d r e m a r k s. Pollen of Juhaszia portugallica occurs in an elongate clump composed of a single kind of pollen grain, and may be a fragment of an anther, or perhaps a coprolite ( Text-fig. 44a ). The pollen grains are small, almost circular in equatorial outline, and monocolpate. The colpus is long, extending for the full length of the grains. The exine is semitectate-reticulate and columellate ( Text-fig. 44b–e ). The reticulum is heteropolar and heterobrochate. Lumina are largest in the equatorial region and decrease in size towards the proximal pole where the reticulum is microreticulate ( Text-fig. 44b ). On the distal face lumina are only slightly smaller than lumina in the equatorial parts of the grains, but are smaller close to the colpus margin. The muri are smooth with a slightly flattened to rounded profile and are supported by short, scattered columellae ( Text-fig. 44c ). The colpus margin is distinct with the reticulum continuing to the margin, and the margin formed by the continuing marginal muri. The reticulum loosens easily from the foot layer and several naked grains, which expose the smooth surface of the foot layer, are present in the pollen clump ( Text-fig. 44e ).

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. Subtle grading of the reticulum into finer regions at the distal pole is known for pollen grains described from the Potomac Group sediments ( Walker and Walker 1986) and has been used to compare the fossil grains with pollen of extant monocots. The grains from the Potomac Group differ from those of Juhaszia portugallica in their finer reticulum and very short columellae. Grains of Juhaszia portugallica also show some similarity to grains assigned to the genus Similipollis, but pollen of these two genera differs in the pattern of the grading (see Comments on the genus). Grading of the reticulum that forms a microreticulate-foveolate region at the proximal pole is also know for the pollen associated with Anacostia E.M.FRIIS, K.R.PEDERSEN et P.R.CRANE , but Anacostia pollen grains are trichotomocolpate and also have a microreticulate-foveolate zone bordering the aperture.

Figures

Text-fig. 44. Scanning electron microscope (SEM) images of monocolpate pollen of Juhaszia portugallica gen. et sp. nov. from a fragment of a pollen sac (a–e) and stamen fragment and pollen of Dictyozonia pusilla gen. et sp. nov. (f–k); Torres Vedras locality, Portugal. a) Holotype; fragment of pollen sac that yielded the pollen in (b–e); b) Proximal surface of pollen grain showing reticulate sculpture in the equatorial regions grading into more a continuous foveolate tectum at the proximal pole; c) Reticulum on the proximal surface showing smooth muri delimiting large and small luminae. Muri supported by numerous short columellae that are only loosely attached to the smooth surface of the foot layer; d) Distal surface of pollen grain showing the long colpus and reticulate sculpture with a distinctive pattern of large and small luminae; e) Pollen grain from which the reticulum has become