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
Samylinaea punctata
E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN
sp. nov.
Text-fig. 52a–h
H o l o t y p e. Designated here. S174565 (Torres Vedras sample 44; figured
Text-fig. 52a–h
).
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.
PFN000496 (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: punctatus referring to fine perforations of the tectum.
Text-fig. 51. Scanning electron microscope (SEM) images of tricolpate pollen of
Mcdougallia irregularis
gen. et sp. nov.
from a stamen fragment; Torres Vedras locality, Portugal. a) Holotype; stamen fragment that yielded the pollen in this Text-figure; b) Polar view of tricolpate pollen grain showing the continuous psilate tectum in the apocolpium and the poorly developed discontinuous foveolate-reticulate tectum in the mesocolpial areas, note irregular fold in tectum wall (arrowhead); c) Equatorial view of pollen grain showing the discontinuous tectum in the mesocolpial areas; d) Pollen grains showing variably developed tectum, colpi with a finely granular aperture membrane and the folds (arrowheads) associated with the irregular development of the colpi; e) Orbicule showing faintly striate surface; f) Pollen wall showing very short columellae, thin tectum and thin foot layer. Specimen, TV44-S148215 (holotype). Scale bars 300 Μm (a), 6 Μm (b–d), 3 Μm (e, f).
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 29 µm; width of pollen grains: about 21 µm.
D e s c r i p t i o n a n d r e m a r k s.
Samylinaea punctata
is based on a single pollen clump comprising only one kind of pollen. It is probably a fragment of a stamen (
Text-fig. 52a
). The pollen is of medium size, prolate, with polar axis about 29 µm long and about 21 µm wide at the equator (
Text-fig. 52b, e, g
). The basic arrangement of the apertures is tricolpate, but their arrangement exhibits unusual variation. The colpi are long, reaching almost to the poles (
Text-fig. 52b, g
) and are often irregular and appear branched (
Text-fig. 52e, f, h
). The exine is tectate-punctate, and columellate with short columellae (
Text-fig. 52d
). The tectum and the infratectal columellate layer are of almost equal thickness, each about 0.3–0.4 µm thick, while the foot layer is slightly thinner. The colpus margin is distinct and the colpus membrane coarsely verrucate (
Text-fig. 52b, e, g, h
). Small, spherical orbicules with a finely granular surface occur abundantly on the surface of the pollen grains (
Text-fig. 52c, h
).
Text-fig. 52. Scanning electron microscope (SEM) images of tricolpate pollen of
Samylinaea punctata
gen. et sp. nov
from a pollen clump; Torres Vedras locality, Portugal. a) Pollen clump (probable stamen fragment) that yielded the pollen in this Text-figure; b) Polar view of pollen grain showing two colpi, granular aperture membrane, and punctate tectum; c) Orbicule showing very finely granular surface; d) Pollen wall showing short columellae, well-developed punctate tectum and slightly thinner foot layer; e–h) Pollen grains showing punctate tectum and the folds associated with the irregular development of the colpi. Specimen, TV44-S174565 (holotype; a–h). Scale bars 300 Μm (a), 6 Μm (b, e–h), 3 Μm (c, d).
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. Currently
Samylinaea punctata
is known only from the Torres Vedras site. The triaperturate pollen grains clearly indicate a relationship to eudicots. Pollen of
Samylinaea punctata
shows some similarity with pollen found in situ in the ranunculalean flower
Teixeiraea lusitanica
BALTHAZAR, K.R.PEDERSEN et E.M.FRIIS from the Vale de Água locality (von
Balthazar et al. 2005
), but the pollen grains in
Teixeiraea lusitanica
flowers are smaller, lack the irregular folds, and have larger perforations in the tectum and orbicules that are smaller with a central depression. Tricolpate pollen with tectate-perforate pollen wall and very long colpi resembling the pollen of
Samylinaea punctata
was described from the mid-Aptian-mid-Albian of
Egypt
as Punctitri-Fineret (
Penny 1991
), but this pollen
type
is distinguished by its smaller size and larger perforations (foveolate-microreticulate).