Records of the Western AlIstra/ian MlISCllI1l Supplement No. 58: 249-253 (2000).

First fossil charophytes from Australia: a Sycidiale from the Frasnian(Late Devonian) Mytton Formation of northeastern Australia

Monique Feistl, Raimund Feist1, Ruth Mawson2 and John A. TalenF

1 Institut des Sciences de l'Evolution, UM2, Place Bataillon, 34095 Montpellier (France)2 Centre for Ecostratigraphy and Palaeobiology, Department of Earth and Planetary Sciences,

Macquarie University 2109, Australia

Abstract Sycidium retieu/atul1l Sandberger from a probable early Frasnianhorizon in the Mytton Formation of the Broken River area, northeasternQueensland, is the first fossil charophyte to be reported from Australia. Mostof the gyrogonites of S. reticu/atum are represented by internal mouldsshowing internal features such as the hitherto poorly known oospore andbasal plate morphology. The presence of S. reticu/atzlltz in Queensland extendsthe distribution of charophytes along the North Gondwana margin, and isconsistent with a low latitude climatic zone.

STRATIGRAPHIC CONTEXT (RM. AND J.A.T.)

Charophytes have been found by one of us (RF.)associated with brachiopods, trilobites and tabulatecorals, including alveolitids, in a siltstone nodule inthe Mytton Formation in the Page Creek area of theBroken River region of northeast Queensland atgrid reference 540

7415

1on Wando Vale 1,100,000

topographic sheet, on the left flank of a small gullyabout 100 m above its junction with a larger gullyincised through and forming the type section forthe Stanley Limestone Member. The MyttonFormation, a widespread interval forming theuppermost unit of the Broken River Group, consistsof up to 940 m of mudstones with subordinate lithicarenites and occasional granule and pebbleconglomerates (Withnall, Lang et al. 1992), but ismuch reduced in thickness in the area where thediscovery was made (Figure 1). The sample camefrom between 24.7 and 30 m stratigraphically abovethe erosional surface separating the MyttonFormation from the underlying and prominentlyoutcropping Stanley Limestone Member. The latteris a 65 m unit of bioclastic and oncolitic limestonespassing upwards into limestones with crinoidaldebris, tabulate and rugose corals, and globularstromatoporoids. The Stanley Limestone Memberwas formerly assigned (Lang et al. 1993) to theMytton Formation but is re-interpreted here asrepresenting the final phase in sedimentation-ashallowing upward interval-of the underlyingPapilio Formation, followed by emergence andvalley incision into the upper surface of the StanleyLimestone Member. The lateral extent of thispreviously-overlooked diastem is uncertain.

The valley incised into the Stanley LimestoneMember is approximately 5 m deep; it displays

arenites with limestone clasts presumably derivedfrom the Stanley Limestone Member. Farther up­section, in the Mytton Formation, are two intervalswith limestone ?clasts: a 20 cm interval at about 20m, and another between 24.7 and 30 m above thetop of the Stanley Limestone Member. Many of the?clasts are in fact tabulate corals. If some or all ofthese are indeed clasts, then they would be evidencefor continued erosion of exposed Stanley LimestoneMember for some time after incising of the valleyand infilling of it had taken place at the charophytelocality. We suggest, incidentally, that this diastemis the appropriate level for re-definition of thePapilio\Mytton boundary.

AGE (RM. AND J.A.T.)

No stratigraphically constraining conodonts wereobtained from calcareous matrix from the horizonwhich produced the charophytes nor fromcarbonates in the Mytton Formation between it andthe underlying Stanley Limestone Member, thoughIcriodus symmetricus, a widely distributed but notnarrowly biochronologically constrained species ofconodont, has been obtained from the very top ofthe Stanley Limestone Member as well as fromarenaceous limestones low in the Mytton Formationsouth of Storm Dam (Mawson et al. 1988; Mawsonand Talent 1989).

Associated with the charophytes are tabulatecorals, brachiopods, principally Cyrtospirifer as wellas phacopid and aulacopleurid trilobites (Feist andTalent, this volume) but these do not provideprecision as to age apart from a broad late Givetian­Frasnian allocation. The broadly late Frasnian­Famennian ages assigned to poorly fossiliferous

250 M. Feist, R. Feist, R. Mawson, J.A. Talent

Siltstones with tabulatecorals (especially Alveolites),rugose corals, brachiopods(including gypidulids),charophytes and scraps ofland plants

Apparently unfossilileroussiltstones (on both sides ofsmall gully)

Apparently unlossiliferous sillymudstones

Arenites with limestone clastsinfilling palaeovalley incised(c. 5 m deep) into Stanleylimestone Member

Bedded limestones with crinoidaldebris, tabulate and rugose coralsand globular stromatoporoids

Rather recessive and apparentlyunlossiiilerous sittstones

-......... Prominent interval (c.3Ocm)01 tabulate corals

f Ridge-Iorming arenites. '.0.' .

10

50

60

70m

40c:0'aiE0u.c: 300

~::0

20

Erosional 0 -ty.~Hsurface m

tN

I

o 1000L'__--',__--',

metres

Stanley Limestone Member - up to 90m01 a broad spectrum 01 limestone lithologiesincluding oncolitic/oolitic limestones

Basalt flow

RockfIelds Member 01 Bulgeri Fonnation- conglomerates and arenites

Mytton Formation sensu srricto - severalhundred m 01 line-grained arenites andmudstones

erosional surface

Upper sittstones, mudstones and very finearenites; max. thickness approx.500 m;occasional sheliy fossil hOflzons in the40-60 m beneath the Stanley limestoneMember

Spanner Limestone Member - up to 137m 01 diverse limestone lithologies; micritesto rudrtes with, rarely, calcareous arenrtes

Lower mudstones, siltstones withcalcareous mudstones and, ocx.asionally,nodular limestones and calcareousarenites, becomin\l more arenaceoustowards the SW; thickness approx.75 m(max. approx. 150 m); olten richlyfossililerous

Quaternary

.~-cC:0"~.~

!!Ltj-

20'00' tNI

.... 0 50km'" ''--__...J...__-''

~

Figure 1 Situation of charophyte locality in relation to the Late Devonian-Early Carboniferous sedimentary basins ofthe Townsville hinterland, northeastern Australia (based on Mawson and Talent 1997, Figure 1), in relationto stratigraphic context (from Withnall and Lang 1992), and stratigraphic column through the charophytelocality. Note the 5 m palaeovalley incised into the Stanley Limestone Member.

First record of fossil charophytes from Australia 251

Figure 2 A-I, Sycidium relicu/atum Sandberger, from the Late Devonian (early Frasnian) Mytton Formation, BrokenRiver region, northeastern Australia (an =apical neck; lr =: longitudinal rays; n =nucleus; p =basal plate). A­D, internal moulds of gyrogonites, lateral views of AMF 105234, AMF 105235, AMF 105236 and AMF 105237respectively, (x45). E-I, internal structures of gyrogonites. E, basal plate of AMF 107555, (x300). F, longitudinalrays and polygonal units of AMF 107556, (xSO). G, apical neck of AMF 107557, (x70). H, nucleus (calcified egg)and apical neck of AMF 107558, (x65). I, longitudinal rays and apical neck of AMF 107559, (x78).

marine intercalations in the otherwise essentiallycoastal plain environments represented by thec.3,600 m Bulgeri Formation (S.c. Lang in Withnallet al. 1993) overlying the Mytton Formationdisconformably or with low angular unconforrnity,are speculative and therefore of no inherent valueas regards the age of the charophyte horizon.Theage to be assigned to the charophytes therefore

hinges on the age of the immediately underlyingStanley Limestone Member, and the time-rangeascribed to 1. symmetricus.

Corals from the Stanley Limestone Membersuggest a probable late Givetian age for most if notall of it (Hurnphreys in Withnall et al. 1993). Theincoming of 1. symmetricus at the top of this unit(Mawson and Talent 1989) was earlier accepted as

252

evidence for an earliest Frasnian age for theuppermost Stanley Limestone Member, but this isnow viewed with some hesitation because there areundocumented occurrences of I. symmetricus fromlate in the Givetian (Mawson and Talent 1997: 207­208). Our best assessment, taking the above datainto consideration, including the hiatus at the top ofthe Stanley Limestone Member, is that thecharophyte horizon is most likely early Frasnian inage.

PALAEONTOLOGY (M. F.)

Order Sycidiales Madler 1952

Family Sycidiaceae Karpinsky, 1906

Genus Sycidium Sandberger, 1849

Sycidium reticulatum Sandberger, 1849Figure 2 A-I

Sycidium reticulatum Sandberger, 1849: 672, plate 8B

Sycidium reticulatum Sandberger. Langer, 1991: 308,plate 2, figure 1-3, plate 4, figure 1-3,

MaterialTwo entire gyrogonites, partly included in matrix,

and 120 isolated, more or less complete, internalmoulds.

DescriptionGyrogonite ellipsoid to ovoid, with apical part

wider than basal part, with 18 meridian rays, eachincluding 12-15 hexagonal cells with roundedangles. Basal plate undivided, thicker than wide.Dimensions of the gyrogonites: 775-1575 ].lm inlength, 750-1300 ]1ffi in width. Diameter of apicalopening 180].lm. Basal plate 130].lm in thickness,1l0].lm in diameter. Wall thickness 220-370 ].lm.Oospore length 630].lm, width 580]1ffi.

DiscussionThe charophytes are assigned to a single species

of Sycidium. The material consists mainly of internalmoulds extracted from the rock surface. Althoughthis state of preservation gives an unusualappearance to the gyrogonites, the general shapeand dimensions are readily discernible; in addition,internal features, such as the oospore and basalplate morphology, are reported here for the firsttime.

The species has been reported previously onlyfrom the Eifelian and Givetian of the Rhenish SlateMountains in Germany (Sandberger 1849; Langer1976, 1991). The material from northeasternAustralia, being viewed as most likely earlyFrasnian, may thus be its earliest occurrence.

The Devonian was a period of great

M. Feist, R. Feist, R. Mawson, J.A. Talent

diversification in charophytes (Feist and Grambast­Fessard 1991) and Sycidium is one of the mostimportant genera, both in number of species andoccurrences. This wide distribution is assumed tohave been favoured by close positioning of thecontinental masses during that time. Numerousoccurrences have been reported from Eurarnerica­the North American mid-eontinent (Conkin et al.1972), Avalonia (Sandberger 1849; Langer 1976,1991), Baltica (Russian platform; Karpinsky 1906)­and from the North Gondwana margin in Algeria(Langer 1991), Iran (Feist and Grambast-Fessard1985), South China (Wang 1976; Wang and Lu 1980;Li and Zhou 1982) and NE Australia (herein). Inaddition, the genus occurs in the continentalGondwana (Choubert 1931). Charophytedistribution is in accordance with climatic zonation(Scotese 1997): calcified gyrogonites, especiallylarge ones of Sycidium, are found in tropical andsubtropical latitudes where warm climates facilitateorganic fixation of calcium carbonate. In contrast,the colder Malvinokaffric province of high latitudeSouth Africa has produced only uncalcified casts(Gess and Hiller 1995).

REFERENCES

Choubert, B. (1931). Decouverte d'algues devoniennesdans le Kundelungu superieur du Katanga. Bulletinde la Societe BeIge de Geologie 41: 266-267.

Conkin, J.E., Sawa, T., Coy, R.G. and Salman, A.M.(1972). The Charophyte genus Sycidium in theUpper Devonian of Iowa. Micropaleontology 18: 74­80.

Feist, M. and Grambast-Fessard, N. (1985). Questions surla nature et l'habitat des charophytes paleozolques.Actes du 110eme Congres National des Societes Savantes,Montpellier, Section Science V: 65-75.

Feist, M. and Grambast-Fessard, N. (1991). The genusconcept in Charophyta: evidence from Palaeozoic toRecent. In Riding, R. (ed.), Calcareous Algae andStromatolites: 189-203, Springer Verlag, Berlin.

Feist, R. and Talent, J.A. (2000). Devonian trilobites fromthe Broken River region of northeastern AustraliaRecords of the Western Australian Museum SupplementNo. 58: 65-80.

Gess, KW. and Hiller, N. (1995). Late DevonianCharophytes from the Witteberg group, South Africa.Review of Palaeobotany and Palynology 89: 417-428.

Karpinsky, A.P. (1906). Die Trochilisken. Memoirs of theGeological committee, n.s. 27: 1-86 (Russian), 87-166(German).

Langer, W. (1976). Neufunde von Sycidillm G. Sandberger(nova class., Charophyta?) aus dem Devon der Eifel.Palaontologische Zeitschrift 50: 209-22l.

Langer, W. (1991). Uber Charophyta und einigeForaminiferen aus dem westdeutschen Mitteldevon.Neues Jahrbuch fUr Geologie lInd Paliiontologie,Monatshefte 5: 307-218.

Li, Z. and Zhou, X.G. (1982). Devonian charophytes from

First record of fossil charophytes from Australia

north-eastern Guangxi. Journal of the Wuhan College ofEarth Sciences 16: 49-60.

Mawson, R and Talent, J.A (1989). Late Emsian-Givetianconodont stratigraphy and biofacies-earbonate slopeand offshore shoal to lagoon and nearshore carbonateramp-Broken River, north Queensland, Australia.Courier Forschungsinstut Senckenberg 117: 205-259.

Mawson, R. and Talent, J.A. (1997). Famennian­Tournaisian conodonts and Devonian-EarlyCarboniferous transgressions and regressions innorth-eastern Australia. Geological Society of AmericaSpecial Paper 321: 189-233.

Mawson, R, Talent, J.A., Bear, V.C, Benson, D.5., Brock,G.A, Farrel, J.R, Hyland, KA, Pyemont, RD., Sloan,T.R, Sorentino, L., Stewart, M.L, Trotter, J.A, Wilson,G.A and Simpson, AJ. (1988). Conodont data inrelation to resolution of stage and zonal boundariesfor the Devonian of Australia. In McMillan, N.J.,Embry, A.F. and Glass, D.J. (eds), Devonian of theWorld: Canadian Society of Petroleum Geologists, Memoir14 (Ill): 485-527; Calgary.

Sandberger, G. (1849). Eine neue PolypengattungSycidium aus der Eifel. Neues Jahrbuch fUr Mineralogie,Geognosie, Geologie und Petrefactenkunde 20: 671-672.

Scotese, CR (1997). Continental Drift, 7th edition: 1-79.PALEOMAP Project, Arlington, Texas.

Sloan, T.R., Talent, J.A., Mawson, R, Simpson, AJ.,

253

Brock, G.A, Engelbretsen, M.J., Jell, J.S., Aung, AK,Pfaffenitter, C, Trotter, J. and Withnall, LW. (1995).Conodont data from Silurian-Middle Devoniancarbonate fans, debris flows, allochthonous blocksand adjacent autochthonous platform margins:Broken River and Camel Creek areas, northQueensland, Australia. Courier ForschungsinstitutSenckenberg 182: 1-77.

Wang, Z. (1976). Middle Devonian Sycidium andChovanella from southwest China (in Chinese). ActaPalaeontologia Sinica 15: 175-186.

Wang, Z. and Lu, H.-N. (1980). New discovery ofDevonian charophytes from South China with specialreference to classification and gyrogonite orientationof Trochiliscales and Sycidiales. Acta PalaeontologiaSinica 19: 190-200.

Withnall, LW., Lang, S.c. and 12 others (1992). BrokenRiver Special 1:100,000 geological map. Departmentof Resource Industries, Brisbane.

Withnall, LW., Lang, S.C, Draper, J.J., Fielding, C.R, Jell,J.S., Talent, J.A., Mawson, R., Fleming, P.J.G.,Simpson, A, Blake, P.R, Humphries, M., Jorgenson,P., Grimes, KG. and Scott, M. (1993). Geology of theBroken River Province, north Queensland. QueenslandGeology 4: 1-289.

Manuscript received March 1999; accepted October 1999.