1852 Thinnfeldia rhomboidalis ETTINGSHAUSEN, p. 2-4,
Pl. 1, Figs. 4-7.
1855 Pachypteris thinnfeldi ANDRAE, p. 43-44, Pl. 11,
Fig. 6, Pl. 12, Figs. 7-9.
1969 Thinnfeldia rhomboidalis HUMML, p. 396.
1994 Pachypteris rhomboidalis BARBACKA, p. 7, Pl. 1,
Fig. 3, Pl. 5, Figs. 3, 5.
1997 Pachypteris rhomboidalis DRAGASTAN and POPA, p.
1997 Pachypteris rhomboidalis POPA, p. 81-87, Pl. 1,
Figs. 3-4, Pl. 2, Fig. 6, Text-fig. 4.
The leaf is pinnate, with a stout rachis, 0.7-1 mm wide.
The rachis is not ornamented, having the same position as the pinnules
level. Pinnules are attached in opposed or slightly sub-opposed
position. Their shape is typically rhomboidal, with a narrow base
(1.5-2 mm width), with the acroscopic margin almost parallel to
the rachis, entire margins and rounded apex, having a constant shape.
The midrib is slightly defined, with secondary veins undivided.
The substance of lamina is thick. The leaf is hypostomatic, with
the upper cuticle thicker than the lower one. On the upper cuticle,
the parenchimatous cells are usually square, triangular or irregular
in shape, frequently with irregular anticlinal walls. The midrib
is slightly expressed epidermally on the upper cuticle, but no secondary
veins. The midrib is expressed by rows of parallel, slightly elongated
cells. The stomata are very rare on the upper epidermis, their occurrence
remaining atypical. The lower cuticle has also parenchimatous cells
irregular in shape, with the midrib expressed in the same way, very
pale. The stomata have an elongated ostiole, with guard cells rarely
preserved during maceration. The subsidiary cells form a wide ring
of 3-5 cells irregular in shape, not distributed in a lower plane
with regard to the ostiole. The stomata are randomly distributed
in the whole surface of the pinnule, excepting the midrib and a
narrow zone close to the pinnule’s margin. The margin has
7-12 rows of elongated cells.
The species has been defined by Ettingshausen (1852) as Thinnfeldia
rhomboidalis, on material collected from the Thinnfeld Pit,
in Steierdorf, Anina. Andrae (1855) and Doludenko (1974) emended
the diagnosis of the species on material collected also from Anina,
given by A. Badaluta to V. Vachrameev, attributing the species to
the Pachypteris genus. Humml (1969), Barbacka (1994) described
Romanian material too. Popa (1997, 2000) redescribed material collected
from Anina and Cristian.
The species was collected from Anina, Holbav and Cristian,
all these localities belonging to the Getic Nappe, South Carpathians.
Hettangian-Sinemurian in age.
Marsh, humid areas. P. rhomboidalis is a possible coal
generator in Anina and Holbav.
In Anina, P. rhomboidalis is frequent, well preserved,
with large fragments. The material collected from Holbav and Cristian
is also very well preserved.
Andrae, C., 1855. Beitrage zur kenntniss der fossilen Flora Siebenburgens
und des Banates. Abhandlungen der K. K. geologischen Reichsanstalt,
Ettingshausen, C., 1852. Begrundung einiger neuen
oder nicht genau bekannten Arten der Lias- und Oolithflora. Abhandlungen
der K. K. geologischen Reichsanstalt, 1(3 (3)): 1-10.
Humml, H., 1969. Contributii la flora fosila a
Liasicului inferior de la Steierdorf-Anina. Studii si cercetari
de geologie, geofizica, geografie, Sectia geologie, 14(2): 385-404.
Popa, M.E., 1997. Corystospermal pteridosperms
in the Liassic continental deposits of Romania. Acta Palaeontologica
Popa, M.E., 2000. Early Jurassic land flora of
the Getic Nappe, University of Bucharest, Bucharest, 258 pp.