Gleicheniaceaephyllum kurrianum (HEER) GREGUŠ et J. KVAČEK 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 : 318-319

Gleicheniaceaephyllum kurrianum (HEER) GREGUŠ et J. KVAČEK comb. nov.

Pl. 1, Fig. 1–4; Pl. 2, Fig. 1–2

1869 Gleichenia kurriana HEER, Kreide Fl. Moletein in Mähren. p. 6, pl. 2, fig. 1–4 (Basionym).

1929 Dicranopterites gieseckiana HEER; Domin, p. 241, text-fig. 157.

L e c t o t y p e: GPIT/PL_727, Pl. 1, Fig. 1a, b, designated here; Heer 1869, p. 6, pl. 2, fig. 1.

E p i t y p e: MMT(M)/G_438, Pl. 1, Fig. 2a, b, designated here.

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_25, 157; GPIT/PL_638,

649, 722, 726, 741, 757; MMT(M)/G_335.

O c c u r r e n c e: only the type locality .

E m e n d e d d i a g n o s i s. Pseudodichotomous leaf fronds with resting bud in place of dichotomy of main rachis. Leaf fronds 2–3 pinnate, lanceolate to elongated, almost vertical to main rachis, alternately and densely arranged. Leaf pinnae composed of pinnules touching in basal part each other, apices bluntly rounded. Central veins apparent, simple. Sori rounded, on both sides of central veins.

D e s c r i p t i o n. The lectotype ( GPIT / PL _727, Pl. 1, Fig. 1a, b) described by Heer (1869, p. 6, pl. 2, fig. 1) as Gleichenia kurriana HEER represents a fragment of a bipinnate leaf frond consisting of a main central rachis and almost vertically arranged fertile pinnae. Leaf pinnae are preserved only on one side, 14 mm long and 5 mm wide. On the main rachis, 8 mm along, there is attached a second leaf pinna, 27 mm long and 5 mm wide. Widths of the pinnae are uniform. To the rachis of leaf pinnae are attached, at an obtuse angle, 3–4 mm long and 2–3 mm wide leaf pinnule, with well pronounced central veins. There are 2–3 sori on both sides of the central vein (Pl. 1, Fig. 1b). Leaf pinnules are 2–3 mm apart in the apical parts; in the wider basal parts, the gap is narrower, ocasionally disappearing entirely. The epitype ( MMT ( M)/ G _438, Pl. 1, Fig. 2a, b) is represented by a pseudodichotomous leaf frond, with partially preserved resting bud in the place of division of the main rachis (Pl. 1, Fig. 2b). The leaf frond is 95 mm long, with almost vertically arranged pinnae (28× 5 mm). Leaf pinnae are arranged alternately on the main rachis, approximately 10 mm apart, consisting of smaller pinnules. Leaf pinnules are 3–4 mm long and 2–3 mm wide, apex rounded, touching in basal parts. Sori are not observed .

The fertile pinna no. GPIT/PL_722 (Pl. 1, Fig. 3) is approximately 30 mm long and 5 mm wide. The pinna is stable in width throughout its length. Leaf pinnules slightly tending to narrow to the apex, arranged on 1 mm wide rachis, 3 mm long and 2 mm wide, they slightly touch each other in the basal parts. Within each pinnule, there are two to three sori on both sides of the central vein. Fertile pinnae (GPIT/PL_722, Pl. 1, Fig. 3; GPIT/PL_727, Pl. 1, Fig. 1b) are 2–3 mm apart, while sterile pinnae (GPIT/PL_726, Pl. 1, Fig. 4; GPIT/PL_741, Pl. 2, Fig. 1a, b) almost touch. Other specimens from Maletín are mostly sterile or poorly preserved fragments of leaf fronds, with alternately arranged leaf pinnae. Leaf fragments are up to 120 mm wide. Pinnules are obtuse, rounded in apical parts departing from the rachis at a 90° angle. Leaf pinnae are almost alternately arranged on the main rachis (width is 0.5– 1 mm).

D i s c u s s i o n. The genus Gleichenia is typical in having a pseudodichotomous leaf frond, with a resting bud in the place of division of rachis. This character is present only in the epitype (MMT(M)/G_438, Pl. 1, Fig. 2a, b). Gleicheniaceaephyllum falcatum CRABTREE , from the Albian of SW Montana ( Crabtree 1988) is known only as sterile foliage which does not provide conclusive traits. Individual leaf pinnules of G. falcatum are very similar to the leaf pinnules of G. kurrianum ( Nagalingum and Cantrill 2006) . After detailed comparison with the North American species, they might be identified as the same species. In that case, the name G. kurrianum would have priority over G. falcatum . Gleicheniaceaephyllum acutum NAGALINGUM et CANTRILL from the Albian of Alexander Island, has one sorus per pinnule and pointed apices, in contrast with G. kurrianum ( Nagalingum and Cantrill 2006) . Domin (1929) published the specimen from Maletín (MMT(M)/G_438, Pl. 1, Fig. 2a), selected here as the epitype under the name Dicranopterites gieseckiana HEER. This species, described from the Lower Cretaceous of Greenland´s Kuk locality, differs from G. kurrianum in having remarkably backwards bent leaf pinnules ( Seward and Conway 1935).

Palmacites horridus HEER ( Heer 1869, p. 15, pl. 5, fig. 1) taxon originally interpreted by Heer as a palm remain is probably a remain of fern, most probably poorly preserved frond of G. kurrianum . This specimen shows regularly arranged sub-opposite axes, which resemble secondary rachises of pinnae of G. kurrianum . A similar specimen (GPIT/PL_649) is depicted in Pl. 2, Fig. 2.