Download taxonomic investigation of elements from the early cretaceous

TAXONOMIC INVESTIGATION OF ELEMENTS FROM THE EARLY CRETACEOUS
MEGAFLORA FROM THE MIDDLE CLARENCE VALLEY, NEW ZEALAND.
PART V: A Flower from GONDWANA .
Ian L. Daniel
ABSTRACT
The Middle Clarence Valley of the South Island, New Zealand contains a flora
which is found in outcrops of the Warder and Willows Formations which are of late
Albian-Cenomanian age. The formations consist of fluvial and estuarine sediments and
were deposited in a coastal region of South Gondwana. The palaeolatitude was high
(~75°S), and therefore within the Antarctic Circle. Palaeoclimatic evidence shows that
the climate of polar regions in Cretaceous times was mild temperate and highly equable
at least in coastal regions.
The fossil megaflora of the Middle Clarence Valley contains leaf forms attributable to all
the following plant groups: liverworts, ferns, equisetaleans, cycads, bennettites,
pentoxylaleans, ginkgoaleans, araucariaceans, podocarps, pteridosperms and
dicotyledons. The dicot leaves have been shown to belong to 24 different form species,
some of which have been provisionally assigned to families. The elements investigated
here are a flower with a longitudinal and a transverse section, plus 5 others at varying
attitudes. The foliage species associated with the flower is, at present unknown
Keywords: Gondwana, late Early Cretaceous, Clarence Fossils, Flower, New Zealand.
INTRODUCTION
During the investigation of the mid-Cretaceous Megaflora in the middle Clarence Valley
in Marlborough, New Zealand, (Daniel, 1989, 2005?), one of the major deposits in the
Warder Formation was from Horse Flat [See map p.2]. Earlier, in December 1978 or
April 1979, Professor John Lovis had gone to the Middle Clarence Valley with Myles
Reay and others, to view an upright tree stump. It was at river level, in massive sandstone
(Fig. 47 in Reay, 1993) at East Quail Flat. They went downstream to Horse Flat,
prospecting with a sledehammer. Striking a crevasse splay sandstone boulder in the river,
immediately below an outcrop of Warder Formation, they serendipitously displayed a
layer of leaves and cones. When I started my thesis in Dec.1983, that boulder was the
first number in my collection. The block is 200 x 250 x 80 mm. and has five dicot leaves,
plus fragments of other plants. Unfortunately it lost most of its counterpart, except for
one leaf (100.02a,b Cl). There are 7 flower ‘heads’ in various attitudes.
Undescribed LEAVES
Hughes (1976) described the Early Cretaceous leaves, “the greatest number”
(p.134) of which come from the USSR, including Cinnamomoides ielevii (ibid Figure
10.5). It has venation very similar to those of ?Dalembia leaves from Gondwana. Hughes
used as his source Samylina (1968), who had placed C. ielevii in the family Lauraceae
(p.214)[see Daniel, 2006?, Part III]. Samylina had expressed the opinion that “Early
Cretaceous angiosperms were [should be] identified as organ-genera or form-genera. This
is normal since most living genera apparently did not exist at that time” (ibid p.212).
Hughes himself followed that reasoning in his book, even for ‘families’[and so do I].
Lebedev and Herman (1989) described the new genus Dalembia for leaves from the
Cretaceous (Cenomanian-Senonian) deposits of the Far East of the USSR, for “Pinnate or
palmately-pinnate craspedodromous venation” (ibid, p.78). The most similar species to
the Gondwanan leaves is D. bolschakovae (Lebedev and Herman (1989) Table Ι, Fig. 4
and Plate ΙΙΙ) except it has compound leaves, whereas the Clarence fossil shows no
evidence of being other than simple. D. bolschakovae comes from the Ulyinsky trough
which is Cenomanian.
In my thesis (Daniel, 1989) I referred leaves (previously undescribed) to form species and
to numerotypes. These were grouped into form genera and some assigned to tentative
families (see Daniel, 2006? Part III). None of these are attached to the flowers. Only 12
of the 24 form species leaves are in the same geological horizon.
Liriophyllites parvisinus was described from East Quail Flat, and was verified as
belonging to that genus by David Dilcher himself.
Many leaves from West Quail Flat, and other locations, were not described in
Daniel (1989). The most similar leaf described therein to ?Dalembia sp., was Latifolium
parvilobum (especially the juvenile form). This location (WQF) is described (see Daniel
2005? Fig 1) as situated south of the Clarence River and west of Quail Flat in the
Willows Formation. Several other locations have fossils with similar lobes, and veins at
similar angles to D. bolschakovae. Most leaves are fragmentary, partly because of their
large size, and because they were deciduous.
FLOWER SECTIONS
Vertical Section
The ‘calyx’ consists of 4+ ‘tepals’ in a low amplitude spiral. Within that, two curved
‘hard/black’ carpels enclose anthers and many seeds.
Transverse Section
Five tepals form the outermost layer, and five+ smaller tepals an inner ring/layer. The
different focus levels suggest a low amplitude spiral. Three stigmatic surfaces are
similarly at different heights. Several anthers surround these stigmas. The various organs
being level with each other, suggests pollination by a crawling insect.
Figure 1 - see attachment
Figure 2 - Map of thesis area. - see attachment
ACKNOLEDGEMENTS
Thanks are due to Matt Turnbull for the Museum photos, and Neil Andrews for the SEM
photos.
REFERENCES
Daniel, I.L. 1989: Taxonomic Investigations of Elements from the Early Cretaceous
Megaflora from the Middle Clarence Valley; New Zealand. PhD thesis; University of
Canterbury
Daniel, I.L. 2005?: Taxonomic investigation of elements from the Early Cretaceous
megaflora from the Middle Clarence Valley; New Zealand. Part I; GINKGO and
AGATHIS leaves. (Yet to be published.)
Daniel, I.L. 2006?: Taxonomic investigation of elements from the Early Cretaceous
megaflora from the Middle Clarence Valley; New Zealand. Part III; Proteacae,
Lauraceae and Liriophyllites leaves. (Yet to be published.)
Parrish, J.T.; Daniel, I.L.; Kennedy, E.M.; Spicer, R.A. 1998: Palaeoclimatic significance
of mid-Cretaceous floras from the Middle Clarence Valley, New Zealand. Palaios 13:
p149-159.
Samylina, V.A., 1968. Early Cretaceous angiosperms of the Soviet Union based on
leaf and fruit remains. Journa
l of the Linnean Society, (Botany) 61, 384: 207218.
Hughes, N.F., 1976. Palaeobiology of Angiosperm Origins. Cambridge Earth Science
Series, Cambridge University Press, 242p.
Reay, M.B., 1993. Geology of the Middle Clarence Valley. Institute of Geological and
Nuclear Sciences, Map 10, Lower Hutt, NewZealand.
Lebedev, E.L. and Herman, A.B., 1989. A new genus of Cretaceous Angiosperms Dalembia. Review of Palaeobotany and Palynology 59:77-91