REVIEW OF

PALAEOBOTANY AND

PALYNOLOGY E L S E V I E R Review of Palaeobotany and Palynology 97 (1997) 41-52

Representatives of the genus Nilsonia Brongniart from the Cenomanian of the Bohemian Massif (Czech Republic,

Central Europe)

J i f i K v a ~ e k a,* E r w i n K n o b l o c h b

a National Museum, Prague, Vdtclavskb ndtm. 68, 115 79 Prague 1, Czech Republic b Czech Geological Survey, Kl6rov 131/3, P.O. Box 85, 118 21, Prague 1, Czech Republic

Received 1 February 1996; accepted 16 September 1996

Abstract

Nilson& holyi Kva6ek et Knobloch, sp. nov. is described as a new entire-margined cycadophyte foliage species from the Cenomanian of the Bohemian Massif. It displays entire-margined lamina, a typical emarginate apex, simple secondary veins and a characteristic arrangement of stomata. N. holyi is compared with N. bohemica Velenovsk2~, N. orientalis Heer, N. tenuinervis Seward, N. thomasii Harris and other entire-margined Nilsonia species. New occurrences of N. bohemica are reported from the localities Jet~ichovice and Velk60patovice. Width of leaf lamina is suggested as a good morphological character for Nilsonia bohemica leaf impressions. © 1997 Elsevier Science B.V.

Keywords." Nilsonia; N. bohemica; N. holyi; Cycadophyte foliage; Cenomanian; Cretaceous

1. Introduction

The genus Nilsonia Brongniart is a typical repre- sentative of Jurassic and Lower Cretaceous floras, but its occurrence in the Cenomanian is rather atypical. For this reason all new records from the Cenomanian of the Bohemian Massif are important.

During the "classic period" of investigations of the Cretaceous flora in the Bohemian Massif (1881-1889), only N. bohemica from one locality, namely Prague-MalfiChuchle, was known (Velenovsk~, 1885). Today examples of the genus Nilsonia are known from seven Cenomanian

*Corresponding author. Tel.: +42 2423-0485. Fax: +42 2422-6488. E-mail: ais@nm.anet.cz

0034-6667/97/$17.00 © 1997 Elsevier Science B.V. All rights reserved. PH 0034-6667(96)00064-4

localities in the Czech Republic, namely: (1) Prague-Mal~Chuchle (N. bohemica); (2) Tachlovice (N. bohemica); (3) Pecinov (N. holyi); (4) Jetfichovice (N. bohemica); (5) (~erniky (N. cf. holyi); (6) Brnik (N. cf. holyi vel N. bohemica); and (7) Velk60patovice (N. bohernica)(see Fig. 1 ).

2. Geological setting

The material used in the present study comes from the Peruc-Korycany Formation (Cenomanian) of the Bohemian Cretaceous Basin as defined by Cech et al. (1980). More information relating to the stratigraphy, palaeogeography and palaeontology was published by Malkovsk) in Suk

42 ,L Kvadek, E. Knobloch / Review o f Palaeobotany and Palynology 97 (1997) 41 52

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Fig. 1. M a p showing d i s t r ibu t ion of Nilsonia bohemica Velenovsk~, and Nilsonia holyi Kva6ek et Knob loch , sp. nov. in the Bohemian Massif . / = P r a g u e Malfi Chuchle ; 2 = Tachlovice; 3 = Pecinov; 4 = Jetf ichovice; 5 = (~erniky; 6 = Brnik;

7 = V e l k 6 0 p a t o v i c e .

et al. (1984), Kva6ek (1995), Knobloch (1995) and Uli6n~, and Spi~ikovfi (1996).

Localities mentioned above are described in more detail:

(1) Prague-Malfi Chuchle is one of the oldest localities of the fresh water Cenomanian of the Bohemian Massif. It was introduced to the litera- ture by O. Feistmantel (1875). Although he collected some plant remains there, he never com- pleted his research on Bohemian Cretaceous plants which he had begun prior to 1875. In his preliminary report Feistmantel (1875) referred to the name Taeniopteris kuchelbadensis nom. nud. from the locality Prague-Malfi Chuchle (Kuchelbad) (this is probably identical to N. bohemica). Velenovsk:9 and Bayer continued the collecting of fossil plants in the same place during the second quarter of the 19th century. Bayer focused his interest on leaf compressions (Bayer, 1921).

(2) The Tachlovice locality is situated to the southwest from Prague. Material was obtained by Velenovsk~ and Viniklfi~ in 1913 (Velenovsk~ and

ViniklfiL 1929) from an unknown location at the site.

(3) The Pecinov locality is a large open pit which has been in excavation since 1971 (smaller pits in the same area, known as Ho~kovec, were worked sporadically during the period 1921-1952 and than continually from 1952 to 1971). E. Knobloch collected specimens in the locality during the 1960s and 1970s. Dr. Oplugtil collected there in 1986 and J. Kva6ek has been collecting specimens here since 1991. A list of plant remains was given in the preliminary report by Hol~ (1962) and Knobloch (1969, 1971). The sedimentology was described by Uli6n~ (1992) and Uli6n~ and Spi6fikovfi (1996). The village of Pecinov no longer exists: it was destroyed by mining activities in the open pit. Leaves of Nilsonia have occurred here, albeit rarely, in the freshwater flood plain unit No. 1 as leaf compressions.

(4) In the locality of Jetfichovice, the Peruc-Korycany Formation is not exposed. The Formation was reached by a borehole No. 4009 in depth 3070 3175 m. It was drilled in the surround- ings of Jetfichovice village in 1966 by Jfichymov mining company. Dr. Klein, a sedimentologist employed by the Czech Geological Survey sampled the core and collected leaf compressions of Nilsonia bohemica in dark claystone from the strata lying between 3125 and 3127 m.

(5) The sandstone quarries in the vicinity of the (;erniky village were probably open in the late 19th and early 20th centuries. During that period KopeckS, collected fossil plants from the workings. Only one quarry continued to be worked into the 1930s (Velenovsk~, and Vinikl~iL 1931 ). The mate- rial collected from the quarry site is stored in the collection of the National Museum, Prague.

(6) The Brnik open pit owned by the Keramost a.s. mining company, is situated to the east of the village Brnik. The pit was opened in the 1970s and has been worked continually to the present day. E. Knobloch collected samples of leaf impression in a yellowish sandy claystone.

(7) The original place of the Velk60patovice locality is unknown. Tietze (1902), listing for the first time fossil plants from the locality, stated that the (so-called) "Opatovic clay" was mined in sur- roundings of the village. There are two collections

J. Kva(ek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41 52 43

o f specimens f rom V e l k 6 0 p a t o v i c e . One col lect ion is housed in the Dis t r ic t M u s e u m of Moravskf i T~ebov~i (specimens with red numbers ) and the second is in the M a s a r y k Univers i ty in Brno (specimens bear ing four -p lace numbers ) . The f lora occurs in b r o w n c lays tone as leaf impress ions (except ional ly with t iny pieces o f cuticle pre- served) . A l t h o u g h the first no te referr ing to the local i ty comes f rom Fri6 ( in Fri~ and Bayer , 1901 ), the first t axon f rom there was only descr ibed in much la ter w o r k by K n o b l o c h (1974) as the new genus Velenovsk ia ( incer tae sedis). The comple te f lora was first m e n t i o n e d in two p re l iminary repor t s ( K n o b l o c h , 1994a,b). Subsequent ly , sev- eral leaves o f P l a t a n u s v e l e n o v s k y a n a Krasse r and aft.? P l a t a n u s sp. vel D i c o t y l e d o n i d a e gen. et sp. indet, were descr ibed recent ly by the same a u t h o r ( Knob loch , 1995).

housed in the Dis t r ic t M u s e u m at Moravskf i T~ebovfi and in the col lect ion at the M a s a r y k Univers i ty at Brno.

The fol lowing abbrev ia t ions are used for the collect ions:

( i ) Col lec t ions o f the Pa laeon to log ica l D e p a r t m e n t at the N a t i o n a l Museum, Prague: coll. N M .

(ii) Col lec t ions o f the D e p a r t m e n t o f N a t u r a l Sciences o f the Dis t r ic t M u s e u m at Moravskf i T~ebov~i: coll. MT.

(i i i) Pa laeon to log ica l col lect ions o f the D e p a r t m e n t o f G e o l o g y and Pa l a e on to logy o f the Facu l ty o f N a t u r a l Sciences o f the M a s a r y k Univers i ty at Brno: coll. Brno.

4. Systematic description

3. Material

Specimens f rom the local i t ies Prague-Mal~ i Chuchle , Pecinov, Jetf ichovice, 12erniky and Brnik are housed in the D e p a r t m e n t o f P a l a e o n t o l o g y at the N a t i o n a l Museum, Prague. The ca ta logue number s o f the col lect ions are pref ixed " F " . Specimens f rom the local i ty V e l k 6 0 p a t o v i c e are

Fami ly NILSSONIACEAE Genus N i l s o n i a Brongnia r t , 1825

Diagnos&: A n emended d iagnos is was publ i shed by Har r i s (1964). Acco rd ing to the I C B N rules the or iginal spell ing o f the generic name Ni l son ia

is p refer red over Ni l s son ia ( F a r r et al., 1979, p. 1177; G re u t e r et al., 1994).

Plate I (see p. 44) Nilsonia holyi Kvarek et Knobloch, sp. nov. Pecinov. (coll. NM ). SEM = scanning electron micrograph; LM = light micrograph. 1. Holotype. F 2403a. × 1. 2. Paratype. F 2085. × 2. 3. SEM of the abaxial cuticle showing distribution of the costal (right) and intercostal bands (left), from the holotype F 2403aa. x 200. 4. SEM of the adaxial cuticle. F 2403ab. × 300. 5. LM of the abaxial cuticle showing two stomata. F 2403ac. × 500.

Plate II (see p. 45) SEM = scanning electron micrograph. 1. Nilsonia holyi Kvarek et Knobloch, sp. nov. Pecinov. (coll. NM ). SEM of inner part of the abaxial cuticle showing distribution

v of stomata. F 2403a. x 500. 2. Nilsonia cf. holyi Kva~ek et Knobloch, sp. nov. vel cf. bohemica Velenovsk2? (coll. NM). Basal part of the leaf. Brnik,

F 2402aa. x 1. 3. Nilsonia cf. holyi Kva~ek et Knobloch, sp. nov. (coll. NM). Marginal part of the leaf. I)erniky, F 2152. × 1. 4-6. Nilsonia holyi Kvarek et Knobloch, sp. nov. Pecinov. (coll. NM). 4. SEM of well preserved open stoma, inner surface. F 2403aa. x 1500. 5. SEM of outer surface of the abaxial cuticle showing tiny rounded pits see arrows. F 2403ad. x 300. 6. SEM of inner surface of stoma. F 2403aa. × 1000.

P L A T E I

J. KvaOek, E. Knobloch / Review qf Palaeobotany and Palynology 97 (1997) 41 52

(for explanation see p. 43)

J. Kva6ek, E. KnobIoch / Review of Palaeobotany and Palynology 97 (1997) 41-52 45

P L A T E II

(for explanation see p. 43)

46 J. Kva(ek, E. Knobloch / Review o f Palaeobotanv and Palynology 97 (1997) 41 52

Nilsonia holyi Kvarek et Knobloch, sp. nov. (Plate l, 1-5; Plate II, 1, 4-6; Fig. 2a, b)

Holotype: F 2403a, b (part and counterpart) col- lected by Knobloch in 1967, coll. NM (Plate I, 1). Paratype: F 2085, collected by Oplu~til in 1986, coll. NM (Plate I, 2).

Synonymy: 1969 Nilsonia cf. bohemiea Velenovsk~; Knobloch, p. 147 1971 Nilsonia cf. bohemica Velenovskp; Knobloch, p. 47 1994 Nilsonia sp.; Kvarek, p. 66, pl. 2, figs. 6-8. 1995 Nilsonia cf. orientalis Heer; Kva(zek, p. 394, pl. 2, figs.

1 5, text-fig. 3.

Repository: National Museum, Prague. Type locality: Pecinov open pit, Babin North, flood plain unit No. 1, 1 m above the base of the Peruc Member Stratigraphic horizon: Cretaceous, Cenomanian, Peruc-Korycany Formation, Periec Member.

Etymology: N. holyi is named after a National Museum curator Franti~ek Ho12~ (1935-1984), who first published preliminary results of work on the Cenomanian flora from the locality of Pecinov. Diagnosis: Leaf lamina typically entire-margined oblong to linear, but sometimes irregularly dis- sected; apex emarginate with mucronate tip; lamina tapering below. Secondary veins simple, in marginal part curving forwards, transversing lamina at 2-4 per mm.

Leaves hypostomatic containing resin bodies; adaxial cuticle very slightly differentiated into costal and intercostal zones bearing elongate cells; abaxially costal and intercostal zones well distin- guished; costal zones showing elongated tetragonal cells; intercostal zones bearing isodiametric ordi- nary cells, irregularly scattered and orientated inconspicuous, haplocheilic stomata surrounded typically by 4 subsidiary cells, two of them usually

Fig. 2. a,b. Nilsonia holyi Kvarek et Knobloch, ~p. nov. "one side leaf impressions" turning or folding at the midrib. a. Note the undulate margin and ruptures in the leaf lamina, F 2090. × 1. b. Note the robust midrib, F 2086. x 1. c. Nilsonia bohemica Velenovsk~, apical part of the entire-margined leaf, F 2082. × 1.

J. Kvarek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41-52 47

in lateral position; dorsal parts of guard cells preserved as ledges slightly sunken in rounded pits. Material: The holotype (Plate I, 1) was collected by E. Knobloch in 1967 in the Pecinov open pit. Five specimens were collected subsequently by S. Oplugtil (Faculty of Science, Prague) in 1986. Leaf compressions are preserved in brownish grey silty claystone. They were found in grey claystone lens in a fluvial sand and gravel layer (unit 1 according to Uli~n~ and Spir~ikov~i, 1996). The collection stored in the National Museum contains one apical part (the paratype No. F 2085, Plate I, 2), and four other incomplete specimens (Nos. F 2086, F 2090, F 2150, F 2156) bearing remnants of a cuticle. The cuticle preparations have been pre- pared from the holotype (F 2403a, b) and speci- mens Nos. F 2086, F 2085 and No F 2150.

Specimens studied: F 2085, F 2086, F 2090, F 2150, F 2152, F 2156, F 2402, F 2403a, b. Description: The holotype is the largest and best preserved specimen showing an entire-margined basal part of a leaf with slightly curved undulate margins occasionally dissected (Plate I, 1). Its lamina is flat (incomplete length 120 ram, width 60 mm) with a thick rachis (6 mm). Secondary veins are simple moderately thicker (density 2 per mm). The leaf lamina is gradually tapering to the base (Plate I, 1 ).

Rare lamina ruptures, simulating segmentation parallel to secondary veins, occur in the second largest specimen (F 2090, Fig. 2a). In the basal part of this specimen some ruptures occasionally open forming segments. The paratype, no. F 2085 shows an emarginate apex with a mucronate tip (Plate I, 2). Simple, delicate secondary veins are densely arranged (3-4 veins per mm), transversing the lamina at an angle of 80 ° to the midrib. Laminae of specimens F 2086, F 2090, F 2096 are usually folded along the rachis, so show only one side of the leaf.

The cuticle preparation of the holotype No. F 2403a shows hypostomatic leaves with scattered resin bodies. The adaxial cuticle is moderately thick, bearing well recognizable elongated tetra- gonal or polygonal cells parallel to the secondary veins (Plate I, 4), with nearly straight anticlinal walls. Cells over veins are rather distinct, narrow

elongated (6-15 by 45-100 ~tm). The intercostal cells are more square or tetragonal in shape (12-30 by 30-60 jam).

The abaxial cuticle is very thin. The costal and intercostal zones are well distinguished (Plate I, 3). The costal zones (150-200 lam wide) bear elon- gated tetragonal cells (15-20 by 40-80 ~tm). Intercostal zones bear isodiametric, tetragonal, hexagonal or polygonal cells, with a flat periclinal wall, size 10-20 by 15-40 ~tm. The anticlinal walls are straight or slightly curved. The stomata are small and very inconspicuous, being only poorly observed by light microscope (stomatal apparatus 8-13 by 20-30 ~tm). They are irregularly scattered in intercostal zones (Plate I, 5; Plate II, 1). The aperture is only slightly sunken in rounded pit and is surrounded typically by 4-6 weakly specialised subsidiary cells, typically with two larger lateral ones (Plate II, 4, 6). The guard cells have dorsal thickening preserved as narrow elliptical ledges (5 x 20/am). Subsidiary cells vary in size (15-25 by 15-40 ~tm). The outer surface of the abaxial cuticle is nearly flat (Plate II, 5). The inner margin of the lamina, where it is attached to the rachis, is slightly thickened, papillate, and has strongly cutinised cells.

One incomplete specimen (Plate II, 3) from the locality of (~erniky (No. F 2152) from the old museum collection is macroscopically similar to the material described above, but because it lacks cuticle it might be determined only as Nilsonia cf. holyi. It is a leaf fragment representing a part of leaf lamina 3 cm wide and 4 cm long. The lamina (estimated width 60 mm) bears simple veins arising from the midrib at angle of 80 ° . The veins are simple with a density of 2 per mm.

The only specimen from Brnik locality (No. F 2402) represents a fragment of leaf lamina 4.5 cm long and 2.5 cm wide (Plate II, 2) lacking a cuticle. It narrows towards the base. The veins are simple, arising from the midrib at angle of 85 ° with a density of 2.5 veins per mm. The midrib, 3 mm wide, is typically depressed to the lower side of the lamina, and because of the width, the specimen is interpreted as a basal part of the larger leaf. Because better preserved material is scarce the status of this specimen, determined as N. cf. holyi vel cf. bohemica (Plate II, 2), remains open.

48 J. Kva6ek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41 52

Comparison: Nilsonia holyi differs remarkably from N. bohemica Velenovsk~, in the shape of the apex, in the width of the lamina, and in a different arrangement of the stomatal apparatus. The lower cuticle of N. bohemica displays exposed stomata with broad guard cells. Conversely, N. holyi dis- plays inconspicuous stomata, so typical for the genus Nilsonia, with narrow dorsal thickenings.

As regards the characteristic of "one side leaf impressions" turning or folding at the midrib and undulate margins, N. holyi agrees with the speci- men figured by Van Konijnenburg-van Cittert and Van der Burgh (1989, pl. 3, fig. 5) as N. orientalis Heer, from the Upper Jurassic of Scotland (Culgower, Sutherland). Due to the poorly pre- served cuticle of the Culgower material it is difficult to compare them. Their adaxial cuticles are very similar, but the Bohemian material differs abaxially in lacking papillae on the subsidiary cells. Additionally, N. orientalis Heer, 1878 (p. 18, pl. 6, figs. 5-9) is an aggregate taxon that usually accom- modates entire-margined Nilsonia leaf impressions as regarded by Seward (1917) and Harris (1964). As pointed out by Doludenko and Orlovskaya (1976) the type specimen of N. orientalis (housed in the Geological Institute, Moscow) is a very poor leaf-impression providing no anatomical detail. Moreover, these authors suggest that the type collection consists of more than one natural taxon. N. tenuinervis Seward from the Jurassic of Yorkshire (Harris, 1964) is similar to N. holyi in its entire-margined occasionally dissected lamina and in a similar arrangement of stomata. N. tenuin- ervis shows also well distinguished costal and intercostal bands on the adaxial cuticle. It differs from N. holyi in having an acute apex (Harris,

1964, fig. 13A), and a moderately thin adaxial cuticle.

N. thomasii Harris, 1964 from the Jurassic of Yorkshire agrees well with N. holyi in having entire-margined broad leaves (50 60 mm) with slightly and irregularly incised margins and a sim- ilar emarginate type of the apex. It also has a moderately thick adaxial cuticle. It differs from N. holyi in having ill-defined anticlinal walls of the ordinary cells of the adaxial cuticle and abaxially bearing subsidiary cells with large hollow papillae.

So far as the cuticle is concerned, N. holyi resembles N. tenuicaulis (Phillips) Fox-Strangways from the Jurassic of Yorkshire. It conforms in the arrangement of the lower cuticle, and especially the stomatal apparatus (compare Harris, 1964, fig. 21A, D). It differs macromorphologically in having a strongly segmented lamina, micromor- phologically by showing a different cell arrange- ment in the upper cuticle.

The entire-margined leaf of N. serotina Heer, 1878 (p. 19, pl. 2, figs. 1-5) from the Upper Cretaceous of Sachalin is quite similar to N. holyi. It differs macroscopically by having a rounded apex and microscopically in the nearly isodiametric adaxial cells and in the convex periclinal walls of abaxial ordinary cells (Krassilov, 1979). N. schaumburgensis (Dunker) Nathorst from the German and English Lower Cretaceous (Watson, 1969) differs from N. holyi in having much narrower lamina (3 12 mm) and in the cuticle anatomy.

Additional Nilsonia species are preserved only as impressions. N. johnstrupii Heer, 1882 (p. 44, pl. 6, figs. 1 6), a leaf impression from sandstones of the Atane Formation (Greenland), differs from

Plate III Nilsonia bohemica Velenovsk~. SEM = scanning electron micrograph; LM = light micrograph. 1. Apical part of a leaf. Velk60patovice, No. 53, (coll. MT). x 2. 2. Entire leaf. Velk60patovice, No. 6071, (coll. Brno). x 1. 3. Basal part of a leaf. Velk60patovice, No. 52, (coll. MT). x l. 4. Lectotype. Prague-MalL Chuchle, No. F 243, (coll. NM ) . x 1. 5. LM of the abaxial cuticle showing one stoma. Jet~ichovice, No. F 2405a, (coll. NM ). × 500. 6. Basal part of a leaf. Velk60patovice, No. 6120, (coll. Brno). x 1. 7. SEM of abaxial cuticle, inner surface. Prague-MalL Chuchle, No. F 2082b, (coll. N M ). x 300. 8. LM of very fragmentary cuticle, arrows showing preserved straight anticlinal walls. Velk~ Opatovice, No. 6117, (coll. Brno). x 300.

J. Kva(ek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41-52 49

P L A T E I I I

i ~ ¸ ~ ~i~ . . . . .

~i~ ̧̧ •

50 J. Kva6ek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41 52

N. holyi in having an elliptical lamina and in a lanceolate apex. Other similar leaf impressions: Nilsonia pilifera Samylina, 1976 (p. 48) from the Albian of Omsukchan (Sibirian Far East) and N. jacutica Samylina, 1956 (p. 8) from the Lower Cretaceous of Aldan River (East Siberia). These resemble N. holyi by displaying the same shape of the apex and entire-margined lamina, but differ by having a serrate leaf margin. Ecology: Nilsonia holyi occurs in an assemblage with leaves of angiosperms Grevilleophyllum con- stans (Velenovsk~,) Velenovsk~, and "Eucalyptus" geinitzii (Heer) Heer. It is suspected as a taxon growing in the better drained areas of alluvial plains.

Nilsonia bohemica Velenovsk~, 1885 (Plate III, 1-8; Fig. 2c)

Lectotype: F 243, coll. NM (Kva~ek, 1994). Synonymy: 1875 Taeniopteris kuchelbadensis O. Feistrnantel, p. 269 nom.

ntld. 1885 Nilsonia bohemiea Velenovsk~,, p. 11, pl. 2, figs. 25 28. 1929 Nilsonia bohemica Velenovsk~,; Velenovsk~, and ViniklfiL

p. 4, 21, pl. 20, fig. 6. 1994 Nilsonia bohemiea Velenovsk~,; Knobloch, p. 46. 1994 Nilsonia bohemiea Velenovsk~; Kva6ek, 63, pl. 1, figs.

1 5. 1995 Nilsonia bohemiea Velenovsk~; Kva~ek, p. 393, pl. 1, figs.

1 7, text-fig. 2.

Type locality: Prague-Mal~i Chuchle. Diagnosis: For emended diagnosis see (Kva6ek, 1994, 1995). Material: Leaf compressions and impressions from all the localities discussed in this article are pre- served in dark grey or yellowish sandy claystone. The collection from the Mal l Chuchle locality consists of 17 specimens (coll. NM), the collection from the Jetfichovice consists of four specimens. Thirteen specimens from the Velk6 Opatovice locality are stored in the Moravian collections (coll. Brno, coll. MT).

Specimens studied: F 242, F 243, F 244, F 695, F 696, F 723, F 2081, F 2082, F 2083, F 2087, F 2088, F 2089, F 2158, F 2349, F 2394a, b, F 2395, F 2396, F 2397, F 2398, F 2399, F 2400a, b, F 2401, F 2404-F 2407 (coll. NM ), 6117, 6071, 6118,

6127, 6066, 6112, 6119, 6120 (coll. Brno), 50, 51, 52, 53 (coll. MT). Description: For a detailed description of the mate- rial from Pargue-Mal~i Chuchle locality see Kva~ek (1994, 1995), The leaves show typically parallel-sided, entire-margined lamina. Simple secondary veins arise from the midrib at an angle of 80 85 °. The lectotype displays a dissected apex, the paralectotype is entire-margined and lanceo- late. Specimen no. F 2082 displays a lanceolate apex with two dissections.

A description of the anatomical characters and a discussion of N. bohemica can be found in Kva~ek (1994, 1995). Leaves (mostly leaf impres- sions) from the locality of Velk60patovice were identified as N. bohemica. The only almost com- plete specimen (Plate III, 2) shows a lanceolate entire-margined lamina. The midrib is 1-1.5 mm thick, simple secondary veins arise from the midrib at an angle of 80 ° . Two apical leaf fragments are preserved as impressions. The example illustrated (coll. MT, Plate III, 1 ) shows an oblongate, entire- margined apex with a mucronate tip. Three speci- mens show the basal part of a lamina (Plate III, 2, 3, 6), which gradually narrows to the petiole. The petiole vary in length (20-40 mm) and width ( 1.5-3 mm). The width of leaves extends from 11 to 34 mm (see page 51). Specimen 6117 (coll. Brno) yielded an extremely fragmentary cuticle showing just a few cells with straight anticlinal walls (Plate III, 8).

The material from the locality of Jetfichovice shows several incomplete entire-margined leaf compressions (F 2404-F 2407). The specimens are highly carbonised so it was been necessary to macerate them for a long time in Schulze's solu- tion. The cuticle of specimen no. F 2404 shows the same characters as other cuticle examples from the type locality (Plate III, 5). The most typical features are rounded stomatal apparatus, showing typically 6-8 subsidiary cells, and well pronounced exposed guard cells. Comparison: Comparison of the lamina width of specimens of N. bohemica, and comparison of the lamina width of N. bohemica and N. holyi from the localities under discussion produced interes- ting data.

J. Kvagek, E. Knobloch / Review of Palaeobotany and Palynology 97 (1997) 41 52 51

The widths of leaves from Velk60patovice were: 11, 12, 16, 16, 16, 18, 20, 20, 24, 30, 31, 32 and 34 mm (mean width 21.5 mm).

The widths of leaves published by Velenovsk~ (1885) were: 16, 17, 23 and 23 mm. Other leaves from Prague-Malfi Chuchle were: 18, 18, 26, 22, 13, 27, 11, 22, 17, 14, 20, 24 and 30mm (mean width 20 mm).

The widths of Jetfichovice leaves were: 22, 18 and 21 mm (mean width 20.3 mm). When one compares the mean widths of all the leaves there is a good conformity between the measured populations.

The lamina width of the specimens of N. holyi was: 35, 58, 60 and 60 mm (mean width: 53.2 mm).

Comparison of the specimens of N. bohemica from three localities has shown that the mean width of the leaves is very similar (21.5, 20 and 20.3 mm) and differs remarkably from those of N. holyi (53.2 mm). The majority of the leaves of N. bohemica are entire-margined. Interestingly the lectotype differs from the other specimens in having a well pronounced segmentation of the apex. The result is probably due to the scarcity of apical parts available for a larger comparison. Discussion: Although Velenovsk~ (1885), describ- ing N. bohemica drew attention to, and discussed its similarity with, N. polymorpha Schenk, 1867 (pl. 29; pl. 30, figs. 1-5; Lower Liassic of Hinterholz and Pechgraben, Germany) and N. johnstrupii Heer, 1882 (pl. 6, figs. 1-6; Lower Cretaceous Atane Formation of Greenland), he decided to keep N. bohemica as a separate taxon. Revising Velenovsk~'s opinion we have concluded that N. polymorpha is distinct from N. bohemica. It differs remarkably in its cuticle, having sunken stomata surrounded by subsidiary cells bearing large papillae. Its ordinary epidermal cells over veins bear many trichome bases, and its mesophyll contains a lot of resin bodies. Moreover it differs macroscopically in having typically segmented margins (see Gothan and Weyland, 1954, text- fig. 295b). N. johnstrupii resembles N. bohemica, but differs in the width of leaf (4-5 cm) and in the elliptic shape of lamina (compare Heer, 1882, pl. 6, figs. 2, 5a). As we do not know anatomical details of N. johnstrupii we cannot decide definitely

on the relationship between those two taxa. Macroscopically N. bohemica differs from N. holyi in having narrower lamina and an irregularly dissected or acute apex. Microscopically N. bohem- ica shows conspicuous well-pronounced stomata with very broad cutinised ledges of guard cells. For a detailed comparison between N. bohemica and other Nilsonia species see Kvarek (1995). Palaeoecological remarks: N. bohemica leaves in Velk60patovice and Prague-Malfi Chuchle are accompanied by the same assemblage: Sagenopteris variabilis (Velenovsk~) Velenovsk~, Cunninghamites oxycedrus Presl in Sternberg, Cladophlebis albertsii (Dunker) Seward, Myrtophyllum angustum (Velenovsk3)) Knobloch, "Podozamites" latipennis Heer, "Bignonia" pul- cherrima Bayer, Platanus velenovskyana Krasser (for details see Bayer in Fri6 and Bayer, 1901; Knobloch, 1994a,b).

5. Conclusions

We distinguish two species of Nilsonia in the Bohemian Cenomanian: Nilsonia bohemica and iV. holyi. N. bohemica occurs in five localities. Populations of N. bohemica from Prague-Malfi Chuchle, Jetfichovice and Velk6 Opatovice show good conformity in the mean width of the leaf lamina (20-21.5 mm). N. holyi occurs in the local- ity Pecinov and probably in the locality (2erniky (one indeterminable specimen comes from the locality of Brnik). The mean lamina width of N. holyi is 53.2 mm. We suggest keeping this character as a good indicator for distinguishing the two Bohemian Cenomanian Nilsonia species, especially for the specimens lacking an apex or cuticle.

Acknowledgements

The authors wish to thank Dr. J. Martinkovfi (Museum of Moravsk~i T~ebov~i) and Dr. J. Brzobohat2~ (Masaryk University, Brno) for giving us the opportunity to borrow and study the material from Velk6 Opatovice. We thank Dr. R.L. Leary (Illinois State Museum) and D. Woodhouse

52 J. Kvadek, E. Knob[och / Review of Palaeobotany and Palynology 97 (1997) 41 52

( U n i v e r s i t y o f E a s t L o n d o n ) f o r r e a d i n g t he m a n u -

s c r i p t a n d Dr . I v a n a 12ejkovfi a n d D r . H e l e n a

K v a 6 k o v f i ( N a t i o n a l M u s e u m , P r a g u e ) f o r t h e i r

a s s i s t a n c e w i t h t h e S E M w o r k . B o t h a u t h o r s a r e

p l e a s e d to a c k n o w l e d g e t h e f i n a n c i a l s u p p o r t g i v e n

b y t h e G r a n t A g e n c y o f t h e C z e c h R e p u b l i c (E .

K n o b l o c h : G r a n t N o . 2 0 5 / 9 3 / 0 6 8 0 , J. K v a ~ e k :

G r a n t N o . 2 0 5 / 9 6 / 0 5 2 9 ) .

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