Revision Of Cenomanian Flora From The Maletín Sandstone
Author
Greguš, Josef
Author
Kvaček, Jiří
National Museum Prague, Václavské náměstí 68, 115 79 Praha 1, the Czech Republic; e-mail: greguss. p @ seznam. cz; jiri. kvacek @ nm. cz
text
Acta Musei Nationalis Pragae Series B
2015
2015-12-31
71
3 - 4
315
364
https://www.mendeley.com/catalogue/082df3b6-60cb-3bf0-b664-08deb5a903d7/
journal article
10.14446/AMNP.2015.315
2533-4069
13183727
Myrtoidea geinitzii
(
HEER
ex
SCHIMPER
) J.
KVAČEK
et
GREGUŠ
comb. nov.
Pl. 9, Fig. 1–3; Pl. 10, Fig. 1–5
1869
Myrtophyllum geinitzii
HEER
, p. 22, pl. 11, fig. 3–4, nom. inval.
1869
Myrtophyllum schuebleri
HEER
, p. 23, pl. 11, fig. 2, nom. inval.
1874
Myrtophyllum geinitzii
HEER
ex
SCHIMPER
, p. 30.
1874
Myrtophyllum schuebleri
HEER
ex
SCHIMPER
, p. 30.
1882
Eucalyptus geinitzii
(
HEER
ex
SCHIMPER
)
HEER
, p. 93, pl. 19, fig. 1c, pl. 46, fig. 12c, 13.
1992 “
Eucalyptus
”
geinitzii
(
HEER
ex
SCHIMPER
)
HEER
; Z. Kvaček, p. 346, pl. 1, fig. 1, 2, 6, pl. 2, fig. 1, 2, pl. 3, fig. 1, pl. 4, fig. 1, 3.
L e c t o t y p e: GPIT/PL_750, Pl. 9, Fig. 1a, b; designated by Z.
Kvaček 1992
, p. 346, pl. 1, fig. 1–2;
Heer 1869
, p. 22, pl. 11, fig. 3.
T y p e l o c a l i t y: Maletín.
S t r a t i g r a p h y: Peruc-Korycany Formation, Cenomanian, Upper Cretaceous
M a t e r i a l s t u d i e d: GBA_13, 16, 30, 34, 35, 37, 38, 46, 76, 105, 117, 118, 122, 123, 133, 145, 146, 147, 148, 149, 150, 151, 152, 158, 159; GPIT/PL_633, 733, 744; MMT(M)/G_345, 346, 362, 366, 455, 457, 487; MMT(Z)/G_343, 347, 361, 454, 466; MZM/118_1, 26, 28, 63, 69, 72; NHMW_16, 23, 27; UGV_6, 15.
O c c u r r e n c e s: Vyšehořovice, Praha-Malá Chuchle,
Kounice.
E m e n d e d d i a g n o s i s. Simple, entire-margined leaf, broadly elongate to widely lanceolate, widest at 1/3 to 1/2 of the leaf lamina. Venation pinnate, brochidodromous. Terminal parts of secondary veins forming intramarginal vein. Intersecondary veins distributed irregularly among secondaries.
D e s c r i p t i o n. The
lectotype
(GPIT/PL_750, Pl. 9, Fig. 1a, b) described by
Heer (1869
, p. 22, pl. 11, fig. 3.) as
Myrtophyllum geinitzi
is a
150 mm
long impression of simple, entire-margined leaf, without preserved base and apex. Lanceolate leaf is widest at its midpoint (
27 mm
), gently narrowing to its base and apex. The midvein is clearly apparent, slightly protruding to the apical part of the leaf. Venation is pinnate, with delicate secondary veins running out at a 40° angle from the midvein. Secondary veins join in a series of prominent arches, forming an intramarginal vein (Pl. 9, Fig. 1b). Third order venation is not apparent. The second type specimen no. GPIT/PL_744 (Pl. 9, Fig. 3) described by
Heer (1869
, p. 22, pl. 11, fig. 4) as
M. geinitzi
is a
130 mm
long impression of a simple, entire-margined leaf, without preserved apical part. Leaf lanceolately elongate, widest at the midpoint (
23 mm
), gently narrowing to both its base and apex. Base is cuneate, with relatively wide petiole (
3 mm
wide,
17 mm
long). Midvein is slightly protruding to the apical part of the leaf. Secondary veins brochydodromous, and poorly preserved, departing from midvein at a 35° angle. The intramarginal vein is clearly apparent. Specimen (GPIT/PL_733, Pl. 9, Fig. 2) described by
Heer (1869
, p. 22, pl. 11, fig. 2) as
Myrtophyllum schuebleri
is a fragment of a middle part of a leaf,
65 mm
long and
35 mm
wide. No apical or basal parts are preserved. It is an entire-margined leaf, with well-preserved venation: pinnate primary venation, brochidodromous secondary venation. Secondary veins depart from the midvein at a 40° angle. In terminal parts, they form an intramarginal vein. Tertiary venation forms a reticulate – percurrent pattern.
Other material from Maletín consists of 49 pieces of complete and almost complete lauroid leaf impressions. These impressions are always entire-margined, lanceolately elongate, widest at 1/3–1/2 of their length. Bases are narrowly to longitudinally cuneate. Apices are acute to acuminate (GBA_133, Pl. 10, Fig. 1a; GBA_145, Pl. 10, Fig. 4). Specimen (NHMW_27, Pl. 10, Fig. 2a) has the base sharply convex. Some specimens have a preserved petiole (up to
15 mm
long), which is relatively wide compared with the main midvein (UGV_6, Pl. 10, Fig. 3b). On average, leaves are
185 mm
long (from
83 mm
to
240 mm
) and
30 mm
wide (from
12 mm
to
45 mm
), with an average length to width ratio of 6.4 (ranging from 4.6 to 9.8). Specimen no. MMT(Z)/G_343 (Pl. 10, Fig. 5), despite missing its apex, is
275 mm
long. Leaf impressions have a relatively wide midvein, which gently protrudes towards the leaf apex. Delicate brochidodromous secondary veins depart at an angle of 30–40° from the midvein, forming an intramarginal vein (GBA_133, Pl. 10, Fig. 1b; NHMW_27, Pl. 10, Fig. 2b; UGV_6, Pl. 10, Fig. 3a). Percurrent venation of higher order is apparent.
D i s c u s s i o n. We classify all entire-margined leaf impressions with lancolately elongate leaf lamina with pronounced intramarginal vein as
Myrtoidea geinitzii
.
M. geinitzii
shows wider leaves and overall bigger size of lamina with acuminate apex, compared to
M. patagonica
described from the Cenomanian of
Argentina
.
M. geinitzii
has leaves widest at 1/3 to 1/2 of their length, with length to width ratio between 4–9.8, while
M. patagonica
is widest at 2/3 of its length, and length to width ratio is 2–4.5 (
Passalia et al. 2001
).
M. geinitzii
differs from
M. angustum
in larger size, and in length to width ratio, which is
7–13 in
M. angustum
.
Classification of other material described as
Ficus krausiana
and
Ficus mohliana
is problematic.
F. krausiana
HEER
and
F. mohliana
HEER
have L/W ratio (3.7–4), which is lower than in
M. geinitzii
. This observation is in agreement with statement of
Frič and Bayer (1901)
, who suggested that
F. krausiana
and
F. mohliana
are just wider forms of leaves of genus
M. geinitzii
. This hypothesis is possible, however, the above-mentioned species of
Ficus
described by
Heer (1869)
lack an intramarginal vein, which is the most important diagnostic character of the genus
Myrtoidea
.