Full text of DOI:10.1007/BF02959446

Vol. 43 No. 4
SCIENCE IN CHINA (Series D)
August 2000
Klukiopsis jurassicaüüA new Jurassic schizaeaceous fern
from China
DENG Shenghui (Ԍಛ݊)1 & WANG Shijun (ฆೂࢎ)2
1. Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
2. Botany Institute, Chinese Academy of Sciences, Beijing 100093, China
Correspondence should be addressed to Deng Shenghui (email: dsh63@263.net)
Received April 7, 1999
Abstract A new Jurassic schizaeaceous fern Klukiopsis jurassica gen. et sp. nov. from Yima,
Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in
two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.
Keywords: Jurassic, Schizaeaceae, new genus, China.
The earliest schizaeaceous fern has once been considered as Senftenbergia which occurs in
the Carboniferous. But an anatomic study shows that it differs from the extant Schizaeaceae[1].
The real schizaeaceous ferns appear reliably in the Jurassic, which are represented by Klukia and
Stachypteris. However, the two genera have only a few species respectively. In the Early Creta-
ceous, the Schizaeaceae were widely distributed, including Ruffordia, Schizaeopsis, Schizaeangi-
um, Schizaeopteris, Pelletixia and Anemia. Another genus Lygodium has not been recorded until
the Late Cretaceous. Generally speaking, Schizaeaceae have a low species diversity in the Meso-
zoic. The total number may not exceed 20 species, among which only a few species have been
reported from the Jurassic, while most are of great stratigraphic significance. A large quantity of
the dispersed spores of the Schizaeaceae, represented by Cicatricosisporites, existed in the Early
Cretaceous, and is usually considered as important evidence of Cretaceous stratigraphic division
and correlation.
Recently, we have collected some well-preserved plant fossils including fertile pinnae from
Yima basin, Henan Province, China. By means of a microscope and a scanning electronic micro-
scope, we found that the sporangia are borne on the abaxial surface of the pinnules, arranged in
two rows, globular or barrel shaped with apical and complete annuli. These features indicate that
these fossils belong to Schizaeaceae. Because they have more than 800 spores per sporangium and
the trilete spores with smooth surface, the current materials are different from the known genera of
both fossil and living schizaeaceous ferns. We decided to erect a new genus and herein named
Klukiopsis.
1
Materials and methods
The materials studied in the present paper were collected from the Yima Formation of Yima

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357
basin, Henan Province, China. The coal-bearing Yima Formation is rich in plant, spore-pollen and
bivalve fossils. It is assigned to the upper Lower Jurassic based on the bivalves[2], to the
ü
Lower-Middle Jurassic on spore-pollen and to the lower Middle Jurassic on plants[3 5]. The fertile
pinnae were preserved together with the sterile ones in dark mudstones.
The fertile pinnae were firstly observed and photographed under a stereo microscope. A small
piece of the rock with fossil material was then taken from the specimen. This sample was im-
mersed in hydrofluoric acid for 48 h. Some sporangia with complete annuli were laid on standard
stubs after being washed with distilled water, and then examined under a scanning electronic mi-
croscope (SEM). The other materials were macerated with Schulze’s solution or sodium hy-
pochlorite for 24 h and afterwards treated with ammonium hydroxide or sodium hydroxide solu-
tion. In order to calculate the spore output more accurately, single sporangium was isolated and
moved to a slice, and then broken with a needle. The in situ spores were examined under the scan-
ning electronic microscope as well.
2
Description
See fig. 1.
Pteridophyta
Filicopsida
Schizaeaceae
Klukiopsis gen. nov.
Diagnosis: Frond small, at least three times pinnate. Sterile pinnules, sphenopteroid, with
lobed margins. Venation slender. Fertile pinnae similar to the sterile ones in shape. Fertile pinnules
obviously reduced. Sporangia abaxial, globular or barrel shaped, arranged in two rows, 5—6 pairs
in each pinnule. Annulus apical, entire, consisting of one row thickened cells. Stomium longitudi-
nal. Distal plate consisting of many thin wall cells. Each sporangium with more than 800 trilete
spores. Spores rounded triangular in shape, surface almost smooth.
Generic: Generic name from the Mesozoic schizaeaceous genus Klukia.
Type species: Klukiopsis jurassica.
Holotype: YM98-303 (fig. 1(a)).
Age: Middle Jurassic
Locality: Yima, Henan Province, China.
Frond small, three times pinnate at least. Sterile pinnae preserved together with the fertile
ones, but disconnected with each other. Ultimate rachis smooth, 0.5—0.8 mm thick. Penultimate
rachis smooth, about 1.0 mm thick. Ultimate pinnae alternate, about 10 mm long and 8 mm wide.
Pinnules katadromic, ovate, 3—4 mm long and 2—3 mm broad, apices acute, margins entire or
slightly lobed to 3—4 rounded teeth. The pinnules in the upper part of the pinnae usually entire,
1—2 mm long and 1—1.5 mm broad. Venation slender, sphenopteroid, midrib unclear.

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Fig. 1. Klukiopsis jurassica gen. et sp. nov. (a) A, Fertile pinnae; B, sterile pinnae; ×1. (b) The distal view of the sporangium,
showing the distal plate, ×200, SEM photo. (c) Lateral view of a sporangium, showing the apical and entire annulus, ×150, SEM
photo. (d, e) Spores, ×500. (f) Spores, ×600, SEM photo. (g) Showing the arrangement of the sporangia, ×10.

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Penultimate fertile pinnae lanceolate, sub-opposite to alternate, about 30 mm long and 12
mm wide. Ultimate fertile pinnae 8—10 mm long and 5—8 mm wide, widest at bases. Fertile pin-
nule katadromic, reduced, about 3 mm long and 0.8 mm wide.
Sporangia abaxial, usually with about 11—13 in each pinnule, arranged in two rows; globular
or barrel shaped, sessile, 200—250 ꢀm in diameter. Annulus apical, with 13—15 wall thickened
cells arranged in one row. Stomium longitudinal, consisting of 3—4 relatively thin cells. Distal
plate about 100 ꢀm in diameter, surrounded by the annulus and composed of many thin wall cells.
More than 800 and possibly over 1 000 spores in each sporangium. The spores rounded tri-
angular in polar view, 30—40 ꢀm in diameter, trilete. Laesurae straight, extending to 2/3 of the
diameter, about 10—12 ꢀm long. Surface smooth or ornamented with fine granules. Those unripe
spores usually irregularly wrinkled.
3
Discussion
Based on the following two aspects, the described specimens are attributed to the Schizaeac-
eae. Firstly, the sporangia are abaxially borne on the surface of the pinnules and arranged in two
rows, but not forming a sorus. Secondly, their annuli are apical and complete. The abaxial sporan-
gia arranged in two rows and the apical and complete annulus are the two noticeable characters of
both the fossil and the extant Schizaeaceae. Therefore, it is reliable to place the present fossils to
the Schizaeaceae.
3.1 Comparison with the known schizaeaceous fossils
The detailed comparisons between the new genus and the known Schizaeaceae fossils are
shown in table 1. The known schizaeaceous fossils include Klukia, Stachypteris, Mohriopsis, Ruf-
fordia, Anemia, Schizaeangium, Schizaeopteris, Schizaeopsis, Scleropteris tibetica and Lygodium.
Among them, Lygodium is recorded from the Upper Cretaceous to Quaternary. Its sporangia bise-
riate on marginal spikes. Klukia and Mohriopsis are very similar to the new genus in their sporan-
gia. But the sporangia of Klukia[6] are covered by epidermal hair, and its spore content is
150—400, much smaller than that of the new genus. Moreover, the pit-verrucately sculptured
trilete spores are totally different from the smooth trilete spores of the new genus. Mohriopsis[7], a
new genus discovered from the Upper Jurassic of Madagascar, is similar to the present specimens
in the sterile pinnule shape. But its venation belongs to pecopteroid type and is much stronger than
that of the present specimens. Its membrane is rather thick, similar to that of the African fern
Mohria. Furthermore, a small number of sporangia exist in each pinnule and the spores are still
unknown. The ovate lobed pinnules of the present specimen are different from the linear pinnules
of Ruffordia[8] and the fan-shaped leaves of Schizaeopsis[9]. The fertile part of Stachypteris is
spike-like, terminal on a rachis branch and the spores are strongly sculptured[6]. Scleropteris ti-
betica from the Lower Cretaceous of Tibet was formerly considered to belong to the Pteridosper-
mae[10], but a later discovery of its apical annuli attributed it to the Schizaeaceae[11]. The pinnules

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of this species are decurrented to the rachis, the thickened cells of the annulus are 20—24 in
number, more than that of the new genus. Over 800 spores per sporangium and the smooth surface
of the spores are the most important differences between the new genus and the known
schizaeaceous fossils (table 1). The spores of the known schizaeaceous ferns are usually sculp-
tured strongly, such as the pit-verrucately sculptured in Klukia and Stachypteris, or cicatricately
sculptured in Ruffordia, Anemia, Schizaeangium, Schizaeopteris and Schizaeop-sis[8, 9, 12—17]
.
Additionally, the spores of the new genus are much smaller.
Table 1 Comparison between the new genus and the known Mesozoic Schizaeaceae
Genera
Frond
Fertile part
Sporangium
Annulus
Spores content
more than 800, rounded triangular, well
possibly up to thin, trilete, almost smooth,
Spore
Age
J2
apical, with
small, pinnules
sphenopteroid
abaxially, in
two rows
one row of
Klukiopsis
contracted
13—15 cells 1 000
about 30 ꢀm in diameter
small, pinnules
decurrented
slightly
conracted
abaxially, in
two rows
apical, with
one row cells
rounded triangular, trilete,
sculptured with pits and
verrucae, about 60 ꢀm i n
diameter
150ˉ400
Klukia
J1ˉK1
small, pinnules
sphenopteroid
fertile spike in two rows
terminal on
the pinnae
lying obliquely about 100
in relation to
the spike axis
rounded triangular, trilete,
strongly sculptured with
verrucae, 40ˉ80 ꢀm
in diameter
Stachypteris
J1
ˉ
3
small, pinnules
pecopteroid, mem-
brane thick, veins
strong
contracted
abaxial, in two apical,
rows, in a
consisting of
Mohriopsis
Ruffordia
?
?
J3
small number 20 cells
small, pinnules
sphenopteroid
strongly
conracted
abaxial, in two
rows or scat-
tered
triangular, trilete, cicatri-
cate, 30ˉ60 ꢀm in diame-
ter
apical, 15ˉ25 100ˉ500
cells in one
row
J3?ˉK1
K1
small, frond
fan-like,
dichotomous
fertile axes
terminal on
the frond
triangular, trilete, cicatri-
cate, 70—100 ꢀm
in diameter
Schizaeop-
sis
?
?
?
silicified
in two rows on
the two sides
of the axis
sub-triangular, trilete,
cicatricate, 40—44 ꢀm i n
diameter
apical, 10ˉ12 48ˉ64
cells, with
Schizaean-
gium
fertile part
?
?
J3-K1
distal plate
silicified
fertile part
singly,
scattered
over 120
triangular, trilete, about
40 ꢀm
apical, 12ˉ14
cells in one
row
Schizaeop-
teris
K1
K1
contracted,
with enrolled
pinnules
apical
?
about 120
rounded triangular, trilete,
cicatricate, 28—155 ꢀm
in diameter
Pelletixia
Anemia
?
small, pinnae
sphenopteroid or
pecopteroid
contracted
abaxial, in
apical,
128
?
triangular, trilete, cicatri- K1 to
2—4 rows or consisting of
present
cate, 30—50 ꢀm in
diameter
scattered
15—20 cells
small, pinnules
contracted or abaxial, in two apical,
small, membrane same as
thick, sphenopter- the sterile one
oid
rows
consisting of
20—24 cells
Scleropteris
tibetica
?
K1
Owing to the considerable differences between the present materials and the known genera of
fossil Schizaeaceae, they belong to a new genus, and are named Klukiopsis based on similar Ju-
rassic-Cretaceous genus Klukia.

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3.2 Comparison with the extant Schizaeaceae
The extant Schizaeaceae include 4 genera: Anemia, Mohria, Lygodium and Schizaea. Be-
cause of some differences, the four genera have been sometimes segregated as 3 or 4 families.
Table 2 shows that the new genus is similar to the extant Schizaeaceae in its arrangements of the
sporangia and the position of the annulus. This indicates that the new genus belongs to the
Schizaeaceae. Among the four genera above, the new genus is most like Anemia and Mohria in
having a distal plate on the sporangium, but differs in its smooth spores. The distal plates of Ane-
mia and Mohria are composed of many cells but their spores are cicatricate (sculptured with
ridges and furrows). Lygodium and Schizaea differ from Klukiopsis in the outline of the frond, the
sporangium arrangement and the one cell distal plate. Their smooth exospore and complex perispore
with coarse verrucae characterize the spores of the Lygodium.
Table 2 Comparison between the new genus and the extant Schizaeaceae
Character
Lygodium
Anemia
Mohria
Schizaea
pinnately or
Klukiopsis
contracted,
sporangia biseri- arising at the base of not contracted,
ate on marginal
spikes
the frond, contracted; sporangia situated subdigitately at
sporangia abaxial,
in two rows
Fertile portion
sporangia situated on at the end of
the two sides of the the veins
midrib
the apex of
the laminar axes
pear shaped, with barrel shaped,
a stalk, size of
550 ꢀmh
globular, sessile,
about 850 ꢀmin
diameter
pear shaped, sessile, globular or barrel
size of 450 ꢀmh
750 ꢀm
sessile, size of
400 ꢀmh650 ꢀm
shaped, sessile,
200—250 ꢀm
in diameter
Shape and size
1 000 ꢀm
apical, entire,
consisting of
about 10 cells
apical, entire,
consisting of about
15 cells
apical, entire,
apical, entire,
apical, entire,
consisting of about
13—15 cells
consisting of about consisting of
Annulus
12 cells
about 14—17 cells
Sporangia
with many cells
one cell
about 100 ꢀm i n
diameter, consisting
of many cells
about 100ꢁꢀm in
diameter, consisting
of many cells
Distal plate
one cell
subtended by an naked or partially
outgrowth serving protected by the
protected by the
revolute margin
protected by the
revolute margin
naked
Protected
structure
as an indusium
revolute margin
Spore content
Shape
128
no data
over 800
128ˉ256
128ˉ256
tetrahedral
tetrahedral
tetrahedral
bilateral
tetrahedral
Aperture
trilete
trilete
trilete
monolete
trilete
Spore
tuberculate,
verrucate,
Sculpture
cicatricate
72.8—152.8
cicatricate
109.2—148.2
cicatricate
21.7—87.3
almost smooth
30—40
41.5—130
Diameter/ꢁꢀm
4
Significance of the new genus
The reliable earliest Schizaeaceae represented by Klukia and Stachypteris are discovered
from the Early Jurassic. Klukia is characterized by abaxial sporangia in the two sides of the midrib
and Stachypteris by apical and spike-like fertile portion. The two borne styles of sporangium still
exist in the extant Schizaeaceae. This suggests that the Schizaeaceae are obviously varied in the
Jurassic. The new genus is currently discovered from the Middle Jurassic, but it is uncertain
whether it can be found from the Lower Jurassic or lower beds. Although Klukiopsis is similar to
Klukia and Stachypteris in both the outline and the arrangement of its sporangia, obviously, it is

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more original. First of all, the sporangia of Klukiopsis are naked, while those of Klukia are cov-
ered by epidermal hair, which is similar to the Early Cretaceous ones such as Ruffordia and
Anemia. Secondly, the spore content of Klukiopsis is very large, usually twice as much as that of
the extant and known fossil Schizaeaceae. Thirdly, the spores of Klukiopsis are much smaller than
that of the extant schizaeaceous elements and most of the Mesozoic species in size. Then, it is
likely that Klukiopsis is one of the most original schizaeaceous ferns. Therefore, Klukiopsis is of
great significance to the origin and evolution of the Schizaeaceae.
The Jurassic schizaeaceous ferns have been reported. Most of them are discovered in the
tropical to subtropical Sino-European palaeofloristic area, while very rarely seen in the hu-
mid-warm Siberian palaeofloristic area[18]. Composed mainly of ferns and ginkgoes[4, 5]ˈthe Yima
Flora is very similar to the Jurassic Dameigou Flora of Qaidam Basin, Qinghai[19] and the Men-
tougou Flora of West Hills, Beijing[20]. These floras belong to the Coniopteris—Phoenicopsis
Flora of North China palaeofloristic province, which is situated on the south margin of the Sibe-
rian palaeofloristic area. So far the Schizaeaceae have rarely been reported in this palaeofloristic
province. Consequently, the current discovery is also of great significance to the study of the dis-
tribution and features of the early schizaeaceous ferns.
Acknowledgements
The present paper results from the “Ninth Five Year Plan” project of the CNPCüüThe Division
and Correlation of the Jurassic of North China. The authors are most grateful to Dr. Zhang Xianchun for his useful suggestion on
the identification of the fossils.
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