A mature cupule of Leptostrobus (Czekanowskiales) from the Late Triassic of Queensland

3 Pages·1998·0.71 MB·

by  H T Clifford

A MATURE CUPULE OFT£Pra5'77?05U5'(CZEKAN0WSKIALES) FROM
THE LATE TRIASSIC OF QUEENSLAND
H.T. CLIFFORD ANDN. CAMILLERI
Clifford, H.T. & Camilleri, N. 1998 06 29: A mature cupule of Leptostrobus
(Czekanowskiales) from the Late Triassic of Queensland. Memoirs ofthe Queensland
Museum 42(2): 445-447. Brisbane. ISSN0079-8835.
A
single bivalvatecupuleofLeptostrobus is reportedfrom UpperTriassicsediments ofthe
Ipswich Coal Measures. This record is the oldest known for the genus. Leptostrobus,
Triassic, Australia.
H. Trevor Clifford and Natalie Camilleri, Queensland Museum, PO Box 3300, South
Brisbane 4101, Australia; 21 February 1998.
TheCzechanowskialeswere firstrecognisedas cally similarto some beds inthe Blackstone For-
occurring in Australia when Jones & de Jersey mation (Cranfield et aL,1976). Nonetheless, it is
(1947) recorded Czekanowskia tenuifolia certain the siltstone float is Upper Triassic (de
(Johnston) from Late Triassic Ipswich Coal Jersey, 1975).
Measures. The species had originally been de-
SYSTEMATIC PALAEOBOTANY
scribedbyJohnston (1887) from Lord’s Hill near
Hobart. At that date they were regarded as be-
longing toBaeira agenus ofGinkgoales. On the Order CDzievkiasnioownskGiyamlneossHpaerrrimsae& Miller
basis of its epidermal structure the species B.
Leptostrobus Heer
tenuifolia was transferred to Czekanowskia by
Jones & de Jersey (1947). Leptostrobus cookii sp. nov.
(Figs 1-2)
knTohwen,sitmoilCazrietkyanoofwBs.kiteanumiifcolrioap,hyalslait hwaadsbteheenn ETYMOLOGY. For Alex Cook in recognition ofhis
notedby Walkom(1925), indicatinganoverlapin enthusiasm forallthingsgeological.
gross morphology ofthetwospecies. MATERIAL. Holotype: QMF37262a, (convex) Ips-
In additionto CzekanowskiaJones & deJersey wich, Queensland 27°37’39"S, 152M7’58"E;
QMF37262b,(concave)counterpart.
(1947) also recorded a single presumed cupule-
bearing axis ofLeptostrobus in the same deposit. DIAGNOSIS. Coalifiedcupuleconsistingoftwo
Thecup-shapedorgansaremuchsmallerthanthe similar oppositely placed valves obovate in out-
cupule described here and so may beregarded as line. Internal surface with slightly raised longitu-
immature. dinal ribs. Seeds and ovules missing.
Although Czekanowskia and Leptostrobus DESCRIPTION. Thecupule is completelycoali-
havenotbeen encounteredinorganicconnection, fied and no cell detail is available, T^e scales are
theirfrequentjointoccurrence istakentoindicate obovate in outline, 16mm longand 12mm broad.
that they represent the foliage and cupules ofthe Thethickeningofthevalvecanbeestimatedfrom
same taxon. thefracturedsurfaces. Towards itsapexthevalve
STRATIGRAPHY is abouthalfasthick as at its base (£5-3.0mm).
The inner surface ofone scale is concave and
The specimen described was exposed by the thatoftheotherisconvexwhichsuggeststhatthe
splitting offossiliferous, siltstone float close to a latterhas been pushed intothe formerduring the
dirtWtrack beginning at the end ofThomas St, on process offossilization (Figs I, 2).
the side of ‘Castle HilF, Blackstone. On the
basis of lithology the specimen is considered as DISCUSSION
being in situ. Well-developed cupules ofLeptostrobus have
Whether these siltstones represent a horizon not been reported previously from Australia al-
within the Rhaetian Aberdare Conglomerate or though its associated foliage Czekanowskia (as
the Camian Blackstone Formation is difficult to Baiera) has been known formorethan acentury.
determine with certainty, because the two are Since the Ipswich area, in particular, has been
separated by an unconformity, and siltstones intensively collectedovera longperiod it is clear
within the Aberdare Conglomerate are lithologi- the cupules are rare.
^
446 MEMOIRS OFTHE QUEENSLAND MUSEUM
bedthewoodyfruits ofthetwo
genera are rare (Clifford,
1990).
Seed-bearing structures of
anykindarelikewiserareinthe
Ipswich beds which were also
laid down in freshwater. Aside
from Leptostrobits the only
other seed-bearing structures
recorded in the sediments are
Fraxinopsismajorand apossi-
ble corystosperm megasporo-
&
phyll(Hilletal., 1966;Jones
de Jersey, 1947).
In his original description of
1cm Czekanowskia tenuifolia
Johnston (1887) refered to
abundant associated reproduc-
FIG. I. Internal surfacesofthevalvesofamaturecupuleoftheholotypeof tive structures in the material.
Czekanowskia cookii sp.nov. A, QMF37262a; B, QMF37262b (surface He provided detailed descrip-
convex dueto compression).
tions and some figures but
Asjudgedbytherottingvegetationonthefloor these are difficult to interpret and so will not be
ofa small lake at J.C. Slaughter Falls in the Mt considered further.
Coot-tha Reserve near Brisbane this situation is The presence ofCzekanowskiales in the Trias-
perhapstobeexpected.AlthoughleavesofEuca- sic ofAustraliahasbeen longover-looked. Inthe
lyptus and Corymbia are abundant on the lake- paperin whichthe Orderwasestablished(Harris
&
Miller, 1974) no reference was made to the
workofJones&deJersey(1947)whichwasalso
apparently unknown to either Taylor & Taylor
(1993) or Spome (1974) who claim the Czekan-
owskiales extended only from the Jurassic tothe
Cretaceous.
According to Max Banks (pers. comm.) the
foliage reported from the New Town shales at
Lord’s Hill are Ladinian and so are slightlyolder
than the Ipswich deposits which were laid down
about235MA(Harlandetal., 1989).Thegeologi-
cal range ofthe Czekanowskiales therefore is to
be extended back from the early Jurassic to the
Middle Triassic.
ACKNOWLEDGEMENTS
WethankSarahandCaroleThomasforalerting
ustothesitewherethisspecimenwasfound.John
McKellar ofthe Geological Survey of Queens-
landprovided helpful comments.
LITERATURE CITED
CLIFFORD, H.T. 1990. The historian is a prophet in
reverse. ReviewofPalaeobotanyandPalynology
FIG. 2. Diagrammatic representation ofa mature cu- 64: 5-11.
puleoftheholotypeofC cookiisp. nov.basedonthe CRANFIELD,L.C., SCHWARZBROCK,H. &DAY,
valves illustratedinFig LA, valveQMF37262a. B, R.W. 1976.GeologyoftheIpswichandBrisbane
valveQMF37262b.C,hypotheticalreconstructionof 1:250 000 Sheet Areas. Geological Survey of
cupule. X=valvemargin,f=cracksinwallofvalve. Queensland. Report 95: 1-176.
MATURECUPULE OFLEPTOSTROBUS 447
de JERSEY,NJ. 1975. Miospore Zones in the Lower MesozoicAge in Australia. Papers and Proceed-
Mesozoic ofsoutheastern Queensland. Pp. 159- ings of the Royal Society of Tasmania 1886:
172. InCampbell.K.S.W. (ed.)GondwanaGeol- 160-182.
ogy, Papers presented at the 'fhird Gondwana JONES,O.A.&deJERSEY,N.J. 1947.Thefloraofthe
Symposium, Canberra, Australia 1973. (Austra- Ipswich Coal Measures - morphology and floral
lianNational UniversityPress: Canberra). succession.PapersoftheDepartmentofGeology,
HARLAND, W.B.,ARMSTRONG, R.L.,COX, A.B., University ofQueensIand3(3): 1-88.
CRAIGA, L.C., SMITH, A.G. & SMITH, D.G. SPORNE, K.R. 1974. The morphology of Gymno-
1989. geologic time scale 1989. (Cambridge sperms. (Hutchinson University Library: Lon-
UniversityPress: Cambridge).
HARRIJuSr,assTi.cM.Flo&raMIIVL,L2E.RC,zcJ.ka1n9o7w4s.kiTahleesY.or(kBrsihtiirseh TAYLdOoRn),. T.N. & TAYLOR, E.L. 1993. The biology
Museum NaturalHistoiy: London). and evolution of fossil plants. (Prentice Hall:
HILL, D., PLAYFORD, G. & WOODS, J.T. 1966. EdgewoodCliffs).
WALKOM,
Triassic Fossils ofQueensland. (Queensland Pa- A.B. 1925. Notes on some Tasmanian
laeontographical Society: Brisbane). Mesozoic plants. Part 1. Papers and Proceedings
JOHNSTON, P.M. 1887. Fresh contribution to our ofthe Royal Society ofTasmania 1924: 73-89.
knowledge of our knowledge of the plants of