Myrtoidea geinitzii (HEER ex SCHIMPER) J. KVAČEK et GREGUŠ 2015

Greguš, Josef & Kvaček, Jiří, 2015, Revision Of Cenomanian Flora From The Maletín Sandstone, Acta Musei Nationalis Pragae Series B 71 (3 - 4), pp. 315-364 : 326-327

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 .