Protopteris punctata (STERNBERG) C. PRESL

Greguš, Josef, Kvaček, Jiří & Halamski, Adam T., 2013, Revision Of Protopteris And Oncopteris Tree Fern Stem Casts From The Late Cretaceous Of Central Europe, Acta Musei Nationalis Pragae Series B 69 (1 - 2), pp. 69-83 : 72-74

Protopteris punctata (STERNBERG) C. PRESL in STERNBERG

Pl. 1, figs 1-8, Pl. 2, fig. 1

Synonymy:

1820 Lepidodendron punctatum STERNBERG 1820, p. 20 , 23, pl. 4, fig.1

1822 Filicites punctatus (STERNBERG) MARTIUS , p. 130

1828 Sigillaria punctata (STERNBERG) BRONGNIART , p. 64.

1836 Caulopteris punctata (STERNBERG) GÖPPERT , p. 449

1838 Protopteris punctata (STERNBERG) C. PRESL in STERNBERG, vol. II, 7/8: 170, pl. 65, figs 1-3

1880 Protopteris punctata (STERNBERG) C. PRESL in STERNBERG, Hosius et von der Marck, p. 205, pl. 43, fig. 185

1882 Dicksonia punctata (STERNBERG) HEER , p. 24, pl. 47

1888 Dicksonia punctata (STERNBERG) HEER, Velenovský , p. 20, pl. 5, figs 2-4

1963 Protopteris punctata (STERNBERG) C. PRESL in STERNBERG, Němejc, p. 448, pl. 55, figs 2-3

1871-75 Protopteris punctata (STERBERG) C. PRESL in STERNBERG, Geinitz, p. 304, pl. 67, fig. 1

1845 Protopteris sternbergii CORDA , p. 77, pl. 48, fig. 1, nom. illegit.

1872a Protopteris sternbergii CORDA, O. Feistmantel , p. 26, pl. 2, figs 5, nom. illegit.

1872b Protopteris sternbergii CORDA, O. Feistmantel , p. 214, nom. illegit.

1866 Protopteris debeyi SCHLÜTTER , p. 68

?1896 Protopteris wohlgemuthii FLICHE , p. 21, pl. 1, fig. 2

H o l o t y p e: NMP F1471, coll. National Museum, Prague (pl. 1, figs 1, 4).

T y p e L o c a l i t y: Kounice.

T y p e h o r i z o n: Peruc-Korycany Formation, Cenomanian, Late Cretaceous.

M a t e r i a l s t u d i e d: NMP F212, F213, F214, F1461, F1473, F1474, F1477, F1480, F1492, F2094, F2101, F2128, F3677, F3678, F3679, F3680, F3681, F3682, F3683, F3684, F3685, F3686, F3687, F3688, F3689, F3690, F3691, F3692, F3693, F3694, F3695, F3696, F3697, F3698, F3699, F3700, F3701, F3702, F3703, F3704, F3705, F3706, F3707, F3708, F3709, F3710, F3711, F3712, F3713, F3714, F3715, F3716, F3721, F3722, F3720; MGUWr 7398.p; MMG PB SaK 13.

O c c u r r e n c e: Kounice, Vyšehořovice, Vojice, Paulsdorf in Dippoldiswalde, Germany (Cenomanian); Lwówek Śląski, Poland (Turonian-Coniacian).

E m e n d e d d i a g n o s i s. Stem covered by helically arranged leaf scars; each leaf scar flat, slightly sunken basally into the stem surface. Scar of vascular bundle leaving horseshoe shaped mark. Scars of aerial roots situated directly under each leaf scar leaving several small spherical pits, forming a U-shaped line. Height / width ratio of leaf scars 0.8-1.7; height / width ratio of vascular bundle scars (0.7) 1.0-1.3 (1.5). Stems rarely covered by aerial roots.

D e s c r i p t i o n. The holotype ( NMP F1471 ) described by Sternberg represents part of the stem preserved as a cast showing helically arranged leaf scars (pl. 1, fig. 1). This part of the stem is 130 mm wide, 180 mm tall. The flat or slightly sunken helically arranged leaf scars are oval to spherical in shape. The leaf scars are typically 15 mm wide and 18 mm high (pl. 1, fig. 4). Their density is 20 per 1 dm 2. Each leaf scar contains one scar of vascular bundle resembling a horseshoe. The vascular bundles are 8–11 mm wide and 11–12 mm high. Under the leaf scar there are 5–9 small root scars are seen under the leaf scar. A large tube-like cavity runs through the whole stem, it is 18× 30 mm in cross section. Stem casts are usually flattened ranging from 30× 55 mm to 103× 165 mm in cross section. They are covered by leaf scars of various shapes and sizes showing traces of vascular bundles. The specimens NMP F2128 (pl. 1, fig. 2), F3720 from Vojice and Vyšehořovice ( NMP F 3694 , F3680 ) show extremely small leaf scars. In shape they are almost circular, up to 8 mm in diameter and a density of about 40 per 1 dm 2. The specimens NMP F1474 and F3688 show large leaf scars reaching 23× 28 mm. The height / width ratio of leaf scars varies from 0.9 to 1.4 exceptionally 1.6. The height / width ratio of vascular bundle scars varies even more, from 1.0 to 1.3, exceptionally from 0.7 to 1.4. The mean height / width ratio of leaf scars of all studied specimens is 1.2 ( text-fig. 2 , tab. 1), the mean height / width ratio of vascular bundle scars is 1.2. The specimen NMP F3702 (pl. 1 fig. 8) shows two types of cortical tissue. The lower type shows rather elongate diamond shaped scars (size 10× 40 mm) which are a product of decorticating of the cortex running above which shows a standard pattern of leaf scars (compare pl. 1, fig. 4). The specimen NMP F3692 shows a standard pattern of leaf scars, which is covered by a third type of cortical tissue forming bulging shapes (pl. 1, figs 5, 6). The specimens NMP F1477 , F1480 , F3677 and F3679 show the remains of aerial roots which originally overgrew the leaf scars and formed a several centimetres thick mantel (pl. 1, fig. 9). The specimen MGUWr 7398.p from the Wroclaw University Museum (pl. 2, fig. 1) is particularly illustrative this way. Some specimens from the Kounice locality ( NMP F1471 ), Vojice ( NMP F3720 ) and Vyšehořovice ( NMP F3711 ) show the internal tube-like cavity running through the whole stem cast, as is documented in the holotype. The cavity is oval in cross-section; it is sometimes visible only from one side .

D i s c u s s i o n. In addition to the type species Protopteris punctata , three more species of the genus Protopteris were described from Central Europe. Göppert (1836) described Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG from the Cretaceous of Poland and Engelhardt (1881) described Protopteris laubei (ENGELHARDT) STENZEL from the late Eocene of Staré Sedlo ( Knobloch et al. 1996). Additionally Protopteris witteana SCHENK 1871 was described from the Lower Creataceous of Germany, from the vicinity of Hannover and P. wohlgemuthii FLICHE 1896 from the Lower Cretaceous of Argone. In the present paper, a newly described species P. maletinensis GREGUŠ et J. KVAČEK sp. nov. has been added.

P. laubei , P. maletinensis and P. witteana differ from P. punctata in having large bulgy leaf cushions. P. laubei and P. maletinensis also differ in the mean height / width ratio of leaf scars (see text-fig. 2 and tab. 1). P. laubei , P. maletinensis and P. singeri have a lower height / width ratio of leaf scars (0.4–1.0) than P. punctata (0.8–1.7). Stems of P. singeri show leaf scars less densely arranged, typically with a between scar distance as wide as the leaf scar. P. wohlgemuthii FLICHE shows leaf scars closely packed with a similar height / width ratio representing probably P. punctata .

The size of leaf scars in P. punctata is variable probably depending on the position on the stem and the diameter of the stem. Older stems show scars distributed less densely with broader inter-scar areas. However, the areas never exceed half the width of the leaf scar.

Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG

Pl. 2, figs 2-5

Synonymy:

1836 Caulopteris singeri GÖPPERT , p. 449, pl. 41, figs 1, 2

1838 Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG, vol. II, 7/8: p. 171, pl. 65, figs 7-10

1841 Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG, Göppert, p. 119, pl. 53, figs 1, 2

1845 Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG, Corda, p. 78, pl. 48, fig. 2

1872a Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG, O. Feistmantel, p. 27, pl. 2, fig. 6

1872b Protopteris singeri (GÖPPERT) C. PRESL in STERNBERG, O. Feistmantel, p. 212

H o l o t y p e: MGUWr 2885b.p, coll. Muzeum Geologiczne Uniwersytetu Wrocławskiego, Wrocław (pl. 2, figs 2, 5).

T y p e l o c a l i t y: Żeliszów (Giersdorf), Poland.

T y p e h o r i z o n: Turonian-Coniacian, Late Cretaceous.

M a t e r i a l s t u d i e d: MGUWr 2885a.p.

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. Stem covered by helically arranged leaf scars. Each leaf scar includes one vascular bundle leaving a horseshoe shaped scar. Leaf scars occurring at some considerable distance from each other. Height / width ratio of leaf scars 0.6–0.9; height / width ratio of vascular bundle scars 0.5–0.8.

D e s c r i p t i o n. The holotype (MGUWr 2885b.p) is a fragment of a stem cast consisting of two parts glued together (pl. 2, fig. 2). The fragment of the stem is 56 mm wide, and 128 mm high, showing helically arranged leaf scars. The flat leaf scars are oval to spherical in shape. The leaf scars are typically 12 mm wide and 10 mm high (pl. 2, fig. 5). Leaf scars are arranged at a distance equal to the width of a leaf scar; their density is about 30 per 1 dm 2. Each leaf scar contains one scar of the vascular bundle resembling a horseshoe. Leaf scars are usually slightly sunken into the stem in the apical part and protruding in the basal part, forming a bulging structure but never as developed as in P. maletinensis . The vascular bundles are 5–9 mm wide and 4–5 mm high. The second specimen from the collection (MGUWr 2885a.p) shows a fragment of a stem, 49× 97 mm (pl. 2, fig. 3). Its leaf scars are on average smaller than in the holotype (11 mm wide and 8 mm high, pl. 2, fig. 4). The vascular bundles are 6–8 mm wide and 3–4 mm high. Under the leaf scar there are up to 15 small scars, the remains of aerial roots.

D i s c u s s i o n. Protopteris singeri is similar to P. punctata in having similar shaped scars of leaf vascular bundles. However, it differs from P. punctata in two major characters: in the height / width ratio and larger distances between leaf scars. P. singeri has a height /width ratio usually under 0.9 while P. punctata has a higher value ratio (0.8) 0.9–1.7. P. singeri differs in having leaf scars sparsely distributed. Stems of P. singeri are generally smaller than stems of P. punctata . Protopteris maletinensis , P. laubei and P. witteana differ from P. singeri in the presence of large bulgy leaf cushions. The occurrence of P. singeri in Kounice as reported by Corda (1845) was not confirmed. The specimen mentioned in the text by Corda (1845) was not available for the present study.

Figures

Text-fig. 2. Plot of height versus height to width ratio of leaf scars of the studied species of Protopteris and Oncopteris.