A new Oligocene fern of Dryopteridaceae from the Českéstředohoří Mts (Czech Republic)

Abstract

A new palaeobotanical site was recovered at artificial excavations within the city district of Ústí nad Labem called Mojžíř in northern Bohemia (Czech Republic) that yielded slabs of Oligocene tephritic pyroclastic rocks with plant impressions. The fossiliferous layer belongs to the Děčín Formation of the České středohoří Mts. dated to the Oligocene (30.8–24.7 Ma). One of the recovered fossils belongs to a new leptosporangiate fern matching modern representatives of Polystichum Roth (Dryopteridaceae Herter). These frond fragments are partly fertile and allow studying the position of sori and details of indusia and spores. This fossil fern is described here as a new species of Polystichum, P. pacltovae Kvaček sp. nov., which matches the modern European species of Polystichum , namely Polystichum braunii (Spenner) Fée . Accompanying plant fossils include another fern frond described as " Aspidium " elongatum Heer (non Swartz) of unknown affinities, fragmentary needles assigned to Pinus cf. hepios (Unger) Unger of the Pinaceae and leaf impressions of Betulaceae comparable to Betula brongniartii Ettingshausen.

Full text

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N. Jb. Geol. Paläont. Abh.
www.schweizerbart.deE. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany
1. Introduction
Fern fossils comparable to the Dryopteridaceae are
quite rarely recorded in the Palaeogene. A new locality


(Czech Republic) has yielded fertile foliage worth of
a detailed study including sporangia. Previous records
-

were explored since the 18th
macrofossils described by  (1866),
 (1869),  (1891), -
 (1898),  (1909) and others from this
part of the Czech Republic were sterile or not treated
in detail. Only studies of Polypodium ( 2001)
      
this respect. This study of the newly recovered spec-
imens treated below is a continuation of such efforts.
2. Material and methods
        from

        

    
light grey trachybasaltic pyroclastics containing plant
impressions. It does not crop out in the surround-
ings. According to the local geological map of the
 -
 
        
2000

sensu  (2000) or
 et al. (1999
and  et al. (2001), more spread near the town

Stuttgart,
DOI:
A new Oligocene fern of Dryopteridaceae from the České středohoří
Mts (Czech Republic)
Zlatko Kvaček and Vasilis Teodoridis
With 3 figures
Abstract: 
-


fossils belongs to a new leptosporangiate fern matching modern representatives of Polystichum 
(Dryopteridaceae ). These frond fragments are partly fertile and allow studying the position
of sori and details of indusia and spores. This fossil fern is described here as a new species of Polys-
tichum, P. pacltovae  sp. nov., which matches the modern European species of Polystichum,
namely Polystichum braunii () . Accompanying plant fossils include another fern frond
Aspidium elongatum  (non 
assigned to Pinus cf. hepios ()     
comparable to Betula brongniartii .
Key words: Polystichum, Dryopteridaceae, fertile foliage, Oligocene, Czech Republic.
295/1 (2020), 9–16
January 2020
Article
© 2020
10.1127/njgpa/2020/0864 $ 2.00/2020/08640077-7749
eschweizerbart_xxx

10 Z. Kvaček and V. Teodoridis
       
switched, which is a typical preservation for plant

foliage of a pine and dicotyledonous plants has been
recovered. The leaf material was described using the
current morphological terminology published by 
et al. (2009). The collection was passed over into the

     -
ment details of the fern fossils by various reproduc-
tion technics and the palynological analysis. Despite
repeated maceration of samples by  ,
no in situ spores have been obtained.
3. Systematic palaeobotany

-
gene of Europe. The accompanying plant elements are
additionally reported with short comments.
Polypodiopsida ,  &
W. 
Dryopteridaceae 
Polystichum 
Polystichum pacltovae  sp. nov.
Figs. 11.8, 2.1, 2.2
Etymology: Epithet commemorating Czech palynologist,
-
ty, who died suddenly in Prague on the 2nd February 2019.
Holotype:
11.8.
Other material:
2.1, 2

Type locality:
Type horizon:      

Description: Fern foliage fragmentary, preserved parts of
-
row elongate, up to 60 mm long and 20 mm broad, pinnules
almost of the same size, elongate or slightly falcate, gradu-
ally diminishing in size towards tips of pinnae, arranged in
  
-
date to obliquely truncate, symmetrical, rounded or shortly
decurrent at base, densely spiny toothed on margin, vena-
tion simple free, midrib straight, secondary veins craspe-
  

in 1 row on each side of midrib, in up to 6 pairs or solitary
 
in diameter, centrally attached, partly leaving only rounded
traces.
Discussion:  
and rounded sporangia with peltate indusia refer this fern
to the genus Polystichum. The spiny- toothed margin of ses-
sile pinnules places it near the modern species Polystichum
braunii () , a circumboreal montane to sub mon-
tane evergreen fern growing in deciduous forests (see Fig.
22.6). Different in our opinion are also similar Polys-
tichum setiferum ()  ex , a small
      
  
and strong asymmetry of basal pinnules, and Polystichum
aculeatum ()  ex  (syn. Polystichum
lobatum () ) from western Asia and most of
Europe, which is characterized by differently sized pinnules
within the pinna. Preservation of the fossils at hand does not
       -
quence data of the whole plant. Therefore, it would be futile
to attempt a more satisfactory comparison with the 200 ex-
tant species distributed worldwide ( & 
;  I 2016).
Polypodiopsida familiae et genera indeterminate
Aspidiumelongatum  sensu 
Fig. .1, .2
 Aspidium elongatum , p. 96.
Material:
Description: A single fern frond studied is sterile, of the in-



length, rounded at tips. The rachis is straight, midrib of pin-
Fig. 1. 1–8Polystichum pacltovae  
  

1
sorus from Fig. 1
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A new Oligocene fern of Dryopteridaceae from the České středohoří Mts (Czech Republic)
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nae slightly sinuous, venation of pinnules not well visible,
probably reticulate.
Discussion:        
-
       ;
 2001
Pinopsida 
Pinaceae 
Pinus
Pinus cf. hepios () 
Fig. .6, 
Material:

Description: Needle leaves in pairs, incomplete in length,
ca. 1 mm broad, entire- margined.
Fig. 2. 1, 2Polystichum pacltovae 
3–5Polystichum braunii () , Rossia subcarpatica,
& 

Z. Kvaček and V. Teodoridis
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Fig. 3. 1, 2“Aspidium” elongatum 
3–5Betula brongniartii 
-
6, 7Pinus cf. hepios ()  and Betula brongniartii ,

A new Oligocene fern of Dryopteridaceae from the České středohoří Mts (Czech Republic)
eschweizerbart_xxx

14
Discussion: The sporadically occurring pine foliage is
     
-
        
et al. 2018  
 1901). The nee-
dles are associated with cones of Pinus ornata ()
 (&  2008


Betula 
Betula brongniartii 
Fig. 
Material:       
         

Description:


apex acute, margin double sharply serrate, venation craspe-
dodromous, midrib straight, moderate, strong, secondary
veins alternate or subopposite at basal part, thinner, straight,
  -
served, tertiary veins alternate percurrent, straight or curved,
venation of the higher orders poorly visible, regular polyg-
onal reticulate.
Discussion:      Betula
brongniartii match in most respects fossils of birch foli-

 et al. 2018
( et al. 2001-
sil species is characterized particularly by strongly double
serrate margin recalling hornbeam foliage.
4. Notes on the occurrences of ferns in
the Palaeogene of North Bohemia and
adjacent Saxony
Fern fossils are rare in the magmatic complex of the
-
ony. No monographic treatment is available so far, but
     
and partly illustrations of fern macrofossilis besides
       -
ered ferns from there are two: a thelypterid species
called Pronephrium stiriacum () &
  and newly assigned to Cyclosorus
stiriacus ()  &  (
2001&
 2011) and Oligocene sites Kundratice
( &  1998  -
 &     et al.
), as well as Osmunda lignitum () 
 & -
 2011), Kundratice ( &  1998)
& -

as Woodwardia muensteriana ( ) 
   et al. 2018), Polypodium radonii
      2001,
 et al. 2006) and Rumohra recentior ()
&  2011-
& -

       -
 (1891, ) and  (1909) is so far
incompletely revisited. None of the so far described
ferns is related to Polystichum pacltovae, which is ob-
viously a novelty.
According to the accompanying leaf assemblage,
Polystichum pacltovae can be interpreted as a zonal
fern of the ground cover in the broad- leaved decidu-

substrate connected with slope vegetation in volcanic
area.
Acknowledgements


  , who tried to obtain
spores in situ. Curators of the palaeontological collections
 

are also the suggestions and notes made by two reviewers,
namely   and  , on the

        
         

Z. Kvaček and V. Teodoridis
eschweizerbart_xxx

15
References
      

14
 ,   &     
       -

18

      -
75
 ,  ,  ,   & -
      
9
  (2001): Cainozoic ferns and their dis-
   53    

, , , , -
,   & 

Press).

 -

Dresden, 1891
      
-
15
   


1
   (1866): Die fossile Flora des Ter-
       -
    
naturwissenschaftliche Klasse, 26
   (1869): Die fossile Flora des Ter-
       -
    
naturwissenschaftliche Klasse, 29
,  &  (2001): 19th century’s
palaeobotanical types and originals of the Hungarian
-

  &     -
 
42
  (2001): A new fossil species of Polypodium
 -
112

 &  (1998): The Oligocene volcanic
      
-
54
 & -
        
      

60
 & 

67
,  &  (2018): Review

 
74
 & -
-
nus Polystichum
90    


-

Dresden, 1900
       
 
54


       
26
      
-
     

 ,   &   (2006): Oligo-
cene megafossil plant remains and environment from

     -
47:

  &      -
       -
       -
tologie, Abhandlungen, 250   

, ,  & -


27
 &   
      
63

       -

A new Oligocene fern of Dryopteridaceae from the České středohoří Mts (Czech Republic)
eschweizerbart_xxx

16
Addresses of the authors:
-

  

  (corresponding author), Depart-
 
     -
-

Z. Kvaček and V. Teodoridis
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