2000 Pachypteris gradinarui POPA, p. 33-46,
Text-figs. 1-5, Pls. 1-3.
2004 Pachypteris gradinarui GUIGNARD, POPA and BARALE, p. 263-273,
Pl. 1.
Pteridospermopsida/Corystospermales/Incertae sedis
Diagnosis
Bipinnate leaves, rachis longitudinally striated, with a long petiole
and secondary rachises inserted oppositely to suboppositely on the upper
side of the primary rachis. Pinnules rounded to elongated, with contracted
anadromic and decurrent catadromic margins, always inserted on the upper
side of rachis, often overlapping, without any marginal, abaxial thickening
or folding, margins entire, apex atenuated, apical pinnules in a pinna
enlarged. Intercalary pinnules occur occasionally. Pinnule midrib prominent
abaxially; secondary veins macroscopically invisible. Leaves hypostomatic,
the upper cuticle thicker than the lower one. Upper cuticle with polygonal,
rounded epidermal cells, no indication of secondary veins, no papillae.
Lower cuticle with a well-defined midrib represented by rows of slightly
elongated cells, secondary veins indicated near the midrib but not further
to the margin, sometimes showing a single dichotomy. Stomata haplocheilic,
monocyclic or incompletely dicyclic, scattered all over the lower epidermal
surface except the midrib, with sunken and elongated guard cells, 4-7
trapezoid subsidiary cells. In Popa (2000).
Discussion
P. gradinarui has an intresting position within the
Pachypteris group, somehow intermediary between Pachypteris
and Cycadopteris, but it lacks clear marginal thickenings or
folds that characterize the latter genus.
Occurrence
Cristian, Getic Nappe, South Carpathians.
Phytostratigraphy
Sinemurian in age.
Paleoecology
Unknown.
Material
The degree of preservation is very good.
References
Popa, M.E., 2000. Aspects of Romanian Early Jurassic palaeobotany and
palynology. Part II. A new species of Pachypteris from Cristian.
Review of Palaeobotany and Palynology, 111: 31-47.
Guignard, G., Popa, M.E. and Barale, G., 2004. Ultrastructure
of Early Jurassic fossil plant cuticles: Pachypteris gradinarui
POPA. Tissue and Cell: 263-273.