The Early Cretaceous Mesofossil Flora Of Torres Vedras (Ne Of Forte Da Forca), Portugal: A Palaeofloristic Analysis Of An Early Angiosperm Community
Author
Friis, Else Marie
Author
Crane, Peter R.
Author
Pedersen, Kaj Raunsgaard
text
Fossil Imprint
2019
2019-11-25
75
2
153
257
http://dx.doi.org/10.2478/if-2019-0013
journal article
10.2478/if-2019-0013
2533-4069
5386203
Mcdougallia irregularis
E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN
sp. nov.
Text-fig. 51a–f
H o l o t y p e. Designated here. S148215 (Torres Vedras sample 43; figured
Text-fig. 51a–f
).
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.
PFN000494 (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 Latin: irregularis referring to the irregular folds and colpi.
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. Equatorial diameter of pollen grains: about 19–20 µm.
D e s c r i p t i o n a n d r e m a r k s.
Mcdougallia irregularis
is based on a fragment of a stamen, about
0.48 mm
long and
0.135 mm
wide (
Text-fig. 51a
). Pollen grains in situ are small, almost spherical, about 19–20 µm in diameter and tricolpate (
Text-fig. 51b–d
). The colpi are long, reaching almost to the poles and have a distinct margin (
Text-fig. 51b–d
). Shorter folds that appear as openings in the tectum are irregularly spaced between the regular colpi on all grains. The tectum is punctate in the polar regions and along the colpi. In the mesocolpial regions the tectum is foveolate to irregularly reticulate, and sometimes discontinuous (
Text-fig. 51c
). Columellae are very short (
Text-fig. 51f
). The colpus membrane is finely verrucate (
Text-fig. 51c, d
). Orbicules are densely spaced on the inner surface of the anther wall and scattered on the surface of the pollen. They are small and spherical with a faintly striate surface (
Text-fig. 51e
).
Affinity and other occurrences.
Mcdougallia irregularis
is known only from the Torres Vedras locality. The triaperturate pollen grains clearly indicate a relationship to eudicots, but specific relationships to extant taxa within the group are uncertain.