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General stratigraphy of Triassic strata in the Dockum basin, showing depositional sequences 1 and 2 discussed in the text, and correlation with Triassic stages and principal unconformities (Tr-1, Tr-3, and Tr-4) recognized in the western United States by Pipringos and O'Sullivan (1978) and Lucas and Anderson (1993).
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Chatterjee, S., Tewari, R. & Agnihotri, D., 2013. A Dicroidium flora from the Triassic of Allan Hills, South Victoria Land, Transantarctic Mountains, Antarctica. Alcheringa 37, 207-219. ISSN 0311-5518. A heterogenous and well-preserved assemblage of Triassic plants, including pteridophytes and gymnosperms, is described from the Lashly Formation of...
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... same process may have been operative during Triassic time. Vertebrate fossil accumulations are found in the coarse carbonate granule layers, as well as within the lacustrine mudstone, and in surround- ing overbank flood-plain deposits that interfinger with the lacustrine facies ( figure 10). The gran- ular lag deposits of reworked pedogenic carbon- ate nodules in many places contain concentrations of vertebrate teeth and isolated abraded bones. ...
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... our discussion, we have concentrated on the tetrapods only, as they are better represented, easily identified, and useful for biostratigraphic correlation. Major groups of these tetrapods are discussed briefly in a phylogenetic hierarchy ( fig- ure 11) and their stratigraphic ranges are dis- cussed. Eleven important clades of tetrapods have been identified in the Dockum fauna, following the broad phylogenic scheme of Benton (1997 Apachesaurus (Hunt 1993, Davidow-Henry 1989, a small metoposaur (skull length 73-164 mm) has a distinctive shallow otic notch and is known both from the Tecovas and Cooper Canyon. ...
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... tia is known primarily from the Ischigualasto For- mation of South America; however, Lucas and Hunt (1993b) described some fragmentary mater- ial including a scapula, radius and femur from the Santa Rosa Formation of New Mexico, and sug- gested that this taxon served as an index fossil for the 'Ischigualastian' biochron (Lucas 1998). We found a partial skull, mandible ( figure 12A), and few postcranial elements of a new dicynodont in the Cooper Canyon Formation at the Neyland Quarry, thus extending the range of dicynodonts into the upper part of the Dockum Group (Norian). The new Texas dicynodont differs from all late Trias- sic genera with the development of a prominent tusk. ...
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... braincase is expanded and it is enclosed completely as in mammals. Recently we have found a well preserved skull ( figure 12B) and mandible of Libognathus, about 30 mm long, also from the Cooper Canyon Forma- tion, which will provide important new anatomical information for this taxon. ...
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... (1990Lucas ( , 1991 used Doswellia as one of the index taxa for the proposed 'Otischalkian' biochron. However, it remains occur throughout Carnian and Norian deposits ( figure 13). ...
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... and Lucas (1991b) proposed that Paleorhinus characterized a limited strati- graphic interval restricted to the Early Carnian (pre-Tecovas) and erected the 'Otischalkian' bio- zone in part on this basis. However, we have recov- ered a skull and associated skeleton of Paleorhinus from the Cooper Canyon Formation at the Neyland Quarry (Simpson 1998) indicating that the 'Otis- chalkian' biozone cannot be substantiated on the basis of phytosaur occurrence ( figure 12C). Hence, primitive phytosaur taxa such as Paleorhinus and Rutiodon appear to have longer stratigraphic ranges through the Dockum Group sequence than was formerly believed. ...
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... claimed that Redondasaurus is restricted to the Rhaetic, and erected the 'Apachean' bio- zone in part on the basis of this taxon. How- ever, we have collected a skull ( figure 12D) and articulated skeleton of Redondasaurus from the lower part of the Cooper Canyon Formation. This occurrence extends the stratigraphic range of Redondasaurus downward (McQuilkin 1998); and so the 'Apachean' biochron cannot be defined on the basis of this taxon range zone. ...
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... is restricted to the Tecovas Formation ( Long and Murry 1995). Longosuchus is known from the Trujillo and Cooper Canyon, Desmato- suchus from Tecovas through Cooper Canyon, Typothorax from the Santa Rosa to Redonda For- mation ( figure 12E), and Paratypothorax from Tecovas through Cooper Canyon. Aetosaurus is also known from the Cooper Canyon and Redonda Formations. ...
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... Coelophysis -Although hundreds of articulated skeletons of Coelophysis have been recovered from the Upper Chinle Group of Ghost Ranch, New Mexico, no definite Coelophysis remains have been documented from the Dockum Group of Texas (Colbert 1989). Here we report two specimens of Coelophysis from Texas, both collected from the Cooper Canyon Formation in Garza County ( figure 12F-12H). One specimen represents a string of vertebrae, the proximal end of a left femur, the distal end of a left tibia, and an associated astragalus, all from the Lott Ranch. ...
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... specimen represents a string of vertebrae, the proximal end of a left femur, the distal end of a left tibia, and an associated astragalus, all from the Lott Ranch. The femur shows both the fourth trochanter and a lesser trochanter and the highly inturned head (fig- ure 12H). The tibia and astragalus are not fused but separate elements where the ascending process of the astragalus locks into a notch of the distal end of the tibia ( figure 12I). ...
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... femur shows both the fourth trochanter and a lesser trochanter and the highly inturned head (fig- ure 12H). The tibia and astragalus are not fused but separate elements where the ascending process of the astragalus locks into a notch of the distal end of the tibia ( figure 12I). The second specimen is a right ilium, somewhat smaller in size ( figure 12F). ...
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... tibia and astragalus are not fused but separate elements where the ascending process of the astragalus locks into a notch of the distal end of the tibia ( figure 12I). The second specimen is a right ilium, somewhat smaller in size ( figure 12F). It shows a perforated acetabulum and a distinctive brevis shelf. ...
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... 'faunachrons' were designated Otischalkian, Adamanian, Revueltian, and Apachean in ascend- ing order. In their biochronology, the Otischalkian and Adamanian are subdivisions of the Carnian Stage, Revueltian is correlative with the Norian, and the Apachean with the Rhaetian stages of the marine Alpine section ( figure 13). However, our studies have found that the stratigraphic ranges of many Dockum tetrapods actually overlap one another, and are not restricted in the manner sup- posed by Lucas and his associates. ...
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... revised taxo- nomic status and stratigraphic ranges of the index taxa of Lucas and his associates, amplified by our collections, provides little support for the four successive biochrons of the Dockum Group that they have proposed. We have plotted the strati- graphic ranges of the important tetrapod taxa to test the validity of the proposed land vertebrate biochronology ( figure 13). ...
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... have found little biostratigraphic evidence for major generic level evolutionary change within the Dockum succession. Out of thirty-two genera of tetrapods, only one taxon is restricted to Carnian strata and four to Norian strata; the majority of taxa occur throughout the entire range of fossil- bearing sediments in the Dockum Group (figures 4, 13). Our data do not support the Carnian-Norian tetrapod extinction event advocated by Benton (1986Benton ( , 1991. ...
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The Permo-Triassic Victoria Group in South Victoria Land, Antarctica, is a heterogeneous sequence of glacial tillite beds, carbonaceous and non-carbonaceous fluvial deposits, and volcaniclastic strata. The carbonaceous beds are rich in plant fossils associated with coal seams. In Antarctica, the geological record of the Late Paleozoic Ice Age is re...
Citations
... These authors considered that the argentinian Triassic occurrence of Neocalamites carrerei described by Frenguelli (1949), Jain and Delevoryas (1967), Archangelsky et al. (1995), Brea and Artabe (1999) and Morel et al. (2010) would correspond to Zonulamites sp. B. Whereas the specimens described by Artabe and Zamuner (1991) as Nododendron, those of Antarctica reported by Bomfleur et al. (2013) as Neocalamites suberosus, and by Chatterjee et al. (2013) as Neocalamites sp. were assigned to Zonulamites ex 'suberosus', disregarding for complete the descriptions given for such well-preserved specimens. ...
... New Zealand Retallack, 1980-Antarctica Gabites, 1985Barrett et al., 1986;Escapa et al., 2011;Chatterjee et al., 2013Escapa et al., 2011Chatterjee et al., 2013;Bomfleur et al., 2013. discharge during flooding events. ...
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... Palaeofloras recovered from these three units correspond to Dicroidium Flora characterized by the dominance of pteridosperms referred to the Gondwanan endemic family Umkomasiaceae (Balme & Helby 1973;Zamuner et al. 2001;Mays & Mcloughlin 2019). These association also includes cosmopolitan taxa referred to Equisetales (Neocalamites), Osmundales (Cladophlebis), Peltaspermales (Lepidopteris, Scytophyllum), Cycadales (Ctenis), Bennettitales (Pterophyllum, Anomozamites), Ginkgoales (Baiera, Sphenobaiera) and Voltziales (Heidiphyllum) (Anderson & Anderson 1983;Anderson et al. 1999;Spalletti et al. 1999;Artabe et al. 2001;Zamuner et al. 2001;Kustatscher et al. 2018;Stipanicic & Archangelsky 2002;Lutz et al. 2011;Ottone et al. 2011;Chatterjee et al. 2013;Mcloughlin 2001;Pedernera et al. 2019Pedernera et al. , 2020a) (supplementary information Table S1). ...
The impact of volcanic activity and trophic state on the preservation of plant remains from two Triassic palaeolake deposits in western Gondwana is investigated. Six taphonomic modes are identified for the Potrerillos–Cacheuta sequence and the Los Rastros Formation, along with proposed taphonomic pathways for each mode. The taphonomic pathways were compared with those proposed for the Agua de la Zorra Formation, a coeval lacustrine‐deltaic succession. In all three cases, plant preservation in off‐shore lacustrine facies was enhanced by anoxic bottom conditions. In the more proximal near‐shore facies, a high sedimentation rate would have been factor that enhanced the preservation. Variation in relative abundance and taxonomic diversity between the three successions are attributed to ecological differences rather than taphonomic differences among the lake systems. No evidence was recorded that the preserved plant material was produced by volcanic trauma. The preservation of the cuticle recorded in the Cacheuta Formation was likely enhanced by the apparently low thermal maturation of the rock and the presence of tuffaceous horizons. In the three successions, the abundance and distribution of remains throughout the sections suggest that the trophic state of the lake did not influence the preservation of the plant.
... During the Middle to Late Triassic, Gondwana was dominated by the 'Dicroidium Flora' (Balme and Helby, 1973;Zamuner et al., 2001;Mays and Mcloughlin, 2019), characterized by the dominance of pteridosperms referred to the Gondwanan endemic family Umkomasiaceae. This association also includes cosmopolitan taxa referred to Equisetales (Equisetites, Neocalamites), Lycopsida (Pleuromeia), Osmundales (Cladophlebis), Peltaspermales (Lepidopteris, Scytophyllum), Cycadales (Ctenis), Bennettitales (Pterophyllum, Anomozamites), Ginkgoales (Ginkgoites, Baiera, Sphenobaiera) and Voltziales (Heidiphyllum) (Anderson and Anderson, 1983;Anderson et al., 1999;Spalletti et al., 1999;Artabe et al., 2001;Mcloughlin, 2001;Zamuner et al., 2001;Stipanicic and Archangelsky, 2002;Chatterjee et al., 2013;Kustatscher et al., 2018). ...
The Los Rastros Formation was deposited in a deltaic-lacustrine environment during the Late Triassic. Plant remains from the Gualo area were systematically collected and compared with other localities from the Los Rastros Formation concerning the sedimentary evolution of the basin. Subsequently, the Los Rastros paleoflora was contrasted with other Carnian (Upper Triassic) units from Gondwana in a paleobiogeographic context using statistical methodologies: Raup-Crick similarity index and hierarchical cluster analysis. The systematic study revealed 14 taxa for the Los Rastros Formation at the Gualo area. Plant vegetative remains of Equisetales (Neocalamites sp.), Osmundaceae (Cladophlebis sp. cf. C. mesozoica), Umkomasiales (Dicroidium odontopteroides, Johnstonia stelzeriana, Xylopteris argentina, X. elongata, and Zuberia feistmantelii), Ginkgoales (Baiera pontifolia, Sphenobaiera sp. cf. S. argentinae), Voltziales (Heidiphyllum elongatum), Coniferales (Rissikia media), and gymnospermous reproductive structures (Cordaicarpus sp., Samaropsis sp. and strobilus sp. A). The stratigraphic distribution of taxa throughout the Los Rastros Formation in the Gualo section is variable. Diminution of taxa recorded observed across the section could be explained by the isolation of the paleolake product of the activity of a secondary fault. The plant taxa registered at the different localities of the Los Rastros Formation could be related to the location of each locality in the basin and the different depositional conditions during the infill history of the basin at each locality. Comparison among Los Rastros Formation plant records with other paleofloras from Gondwana by statistical analyses indicates differences with respect to a previous paleobiogeographic proposal.
... From the Lashly Formation, Allan Hills, Chatterjee et al. (2013) recorded Dicroidium fremouwense for a leaf impression that should be identified as D. dubium. Three other species were also described from this collection made in the austral summer of 1982/3. ...
Anderson, H.M., Barbacka, M., Bamford, M.K., Holmes, W.B.K. & Anderson, J.M., XX. 2019. Dicroidium (foliage) and affiliated wood; Part 3 of a reassessment of Gondwana Triassic plant genera and a reclassification of some previously attributed. Alcheringa XXX, X–X. ISSN 0311-5518
Dicroidium belonging to Umkomasiaceae (Corystospermaceae) in the polyphyletic pteridosperms (seed-ferns) is reassessed comprehensively worldwide and emended. All records are analysed and some attributed to the genus previously are reclassified. Dicroidium leaves are clearly affiliated with Umkomasia ‘megasporophylls’ and Pteruchus ‘microsporophylls’. The attachments of Dicroidium leaves to stems and associated wood genera are reviewed. Dicroidium is shown to be restricted to the Triassic of Gondwana, where it is by far the most prominent and diverse genus with 23 accepted species. It is well represented in collections from South America, Antarctica, India, Australia, New Zealand and southern Africa from where the Molteno Formation is the most comprehensively sampled stratigraphic unit, yielding numerous species from 75 assemblages. The problems of defining the limits of Dicroidium and its species are addressed. The records of leaf fragments from the Indian Nidpur Flora, Early Triassic, are questionably referable to Dicroidium, whereas the multiple forking leaves from the Cisuralian of India await description as a new peltasperm genus. The forked leaves from the (?)Lopingian of Jordan, previously classified as Dicroidium, are reassessed and placed in the new genus Jordaniopteris.
Heidi M. Anderson [hmsholmes@googlemail.com], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; Maria Barbacka [maria.barbacka@gmail.com], W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, Kraków 31-512, Poland, Botanical Department, Hungarian Natural History Museumartmem H-1431, Budapest, Pf. 137, Hungary; Marion K. Bamford [marion.bamford@wits.ac.za], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; W. B. Keith Holmes [wbkholmes@hotmail.com], 46 Kurrajong Street, Dorrigo, NSW 2453, Australia, University of New England, Armidale, NSW 2351, Australia; John M. Anderson [jmanderson.gondwana@googlemail.com], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa.
... In other papers, Bomfleur et al. (2011aBomfleur et al. ( , 2013 were of the opinion that Switzianthus was the male cone of the leaf Heidiphyllum Retallack, 1981 (a Voltzialean conifer), and disregarded the affiliation of the Odyssianthus male cone as suggested by . Subsequently Chatterjee et al. (2013, fig. 5C) recorded a specimen from the Allan Hills, Antarctica, as Townrovia polaris which, based on the microsporangia radiating from a central receptacle, we consider belongs in Stachyopitys. ...
... Escapa et al. (2011, fig. 8D) and Chatterjee et al. (2013, fig. 4D) recorded specimens from the Allan Hills, Antarctica, as Pteruchus sp. with which we agree. ...
Anderson, H.M., Barbacka, M., Bamford, M.K., Holmes, W.B.K. & Anderson, J.M., XX. 2019. Pteruchus (microsporophyll): part 2 of a reassessment of Gondwana Triassic plant genera and a reclassification of some attributed previously. Alcheringa XXX, X–X. ISSN 0311-5518
The microsporophyll genus Pteruchus, belonging to the pteridosperms (seed ferns) in the family Umkomasiaceae (Corystospermaceae), is reassessed comprehensively worldwide and emended. All records are analysed, and some fertile structures previously attributed are reclassified. The Lower Jurassic record of Pteruchus from Germany is ascribed to a new genus as Muelkirchium septentrionalis. Pteruchus is shown to be restricted to the Triassic of Gondwana and is clearly affiliated with the megasporophyll genus Umkomasia and the vegetative leaf genus Dicroidium. It is well represented from Argentina, Antarctica, Australia and southern Africa; the Molteno Formation of southern Africa is by far the most comprehensively sampled, yielding three species and 425 specimens from 22 localities. Nomenclatural problems with the species of Pteruchus are addressed. A key to Pteruchus species is provided; geographic and stratigraphic distributions are tabulated.
Heidi M. Anderson [hmsholmes@googlemailcom], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; Maria Barbacka [mariabarbacka@gmailcom], W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland; Hungarian Natural History Museum, Botanical Department, H-1431 Budapest, Pf. 137, Hungary; Marion K. Bamford [marionbamford@witsacza], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; W.B. Keith Holmes* [wbkholmes@hotmailcom], 46 Kurrajong Street, Dorrigo, NSW 2453, Australia; John M. Anderson [jmandersongondwana@googlemailcom], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa. *Also affiliated with: University of New England, Armidale, NSW 2351, Australia.
... The Mawson and Ferrar formations are of early and late Jurassic ages, respectively. Chatterjee et al. (2013) have described the stratigraphic setup of the Weller and Lashley formations. The Glossopterisbearing Weller Formation consists of conglomerate, arkosic sandstone, shale, and coal in fining-upwards cycle. ...
Major, trace and rare earth element (REE) geochemistry has been carried out in this paper to characterize source–rock weathering and climatic variability of the late Permian Weller Formation and the late Triassic Lashly Formation of Gondwana sequences which have yielded rich record of plant mega–and micro fossils associated with coal beds in post–glacial conditions in Allan Hills of South Victoria Land, Antarctica. The geochemistry suggests dominantly a felsic provenance with a volcanogenic input and role of weathering and hydrothermal alteration. The palaeoclimatic interpretation derived from geochemical analysis indicates warm, temperate and humid conditions during the late Permian, and warm and humid conditions during the late Triassic.
... Pollen organ CTM, SVL Bomfleur et al. (2011c) Taeniopteris sp. Leaf CTM, SVL Townrow (1967), Axsmith et al. (2000) Telemachus aequata Ovulate organ CTM Yao et al. (1997), Schwendemann et al. (2010) T. antarcticus Ovulate organ SVL Escapa et al. (2010) T. elongatus Ovulate organ CTM, SVL Yao et al. (1993), Axsmith et al. (1995), Escapa et al. (2010Townrovia polaris Pollen organ CTM, SVL Bomfleur et al. (2011b), Chatterjee et al. (2013Umkomasia resinosa Ovulate organ CTM Klavins et al. (2002) U. uniramia Ovulate organ CTM Axsmith et al. (2000) Voltziopsis africana Leaf CTM Retallack (2005) Yelchophyllum omegapetiolaris Leaf CTM Hermsen et al. (2007a) Zamites spp. Leaf SVL Plumstead (1962) Conifer pollen cone Pollen organ CTM Cantrill et al. (1995) was recently suggested to be part of a Kykloxylon trunk rather than Rhexoxylon (Decombeix et al., 2010aDecombeix et al., , 2014). ...
During the first Korea Antarctic Geological Expedition (KAGEX I, 2013/2014), fossil wood was collected from the Triassic fluvial deposits of the Beacon Supergroup at Skinner Ridge in northern Victoria Land, Antarctica. The material is coalified and partially silicified; most specimens are slightly compressed due to burial compaction. In spite of this imperfect preservation, anatomical features of both the xylem and the pith could be observed in some specimens. The xylem displays prominent growth rings and usually araucarioid or somewhat mixed-type radial pitting with some abnormal rings partly composed of parenchymatous tissues. Some specimens also have a wood cylinder that is divided radially by parenchymatous zones. These anatomical features indicate a systematic affinity with Kykloxylon Mey.-Berth., T.N.Taylor et Ed.L.Taylor, a characteristic wood type of the Umkomaciaceae, which flourished throughout Gondwana during the Triassic. The Kykloxylon specimens in this study represent the only wood fossil taxon in the Triassic of Victoria Land, except for a dubious report of Antarcticoxylon Seward in 1914. This may indicate a low diversity of Triassic wood fossils in this area, as in other parts of Antarctica. On the contrary, diverse other gymnosperm organs are known to occur in the Triassic of Antarctica. This low diversity of wood taxa compared to the various plant organs in the Triassic of Antarctica is remarkable. We hypothesize three major reasons for this: 1) the overall structural uniformity of gymnosperm wood compared to other vegetative and especially reproductive organ diversity; 2) the overwhelming dominance of corystosperm plants, with a minor component of voltzialean conifers in the canopy-forming forest vegetation during the Triassic in Antarctica; and 3) the very few systematic studies of fossil wood compared to other plant macrofossils.
... Corystospermaceous fronds belonging to the genus Dicroidium are the most common elements in the Triassic strata throughout the southern hemisphere and the genus has not yet been known beyond the limits of the Triassic. The Dicroidium flora was very much diversified and prolific during the Triassic across the Gondwanan countries (Chatterjee et al., 2013). The Gondwana was intact during the late Triassic and that facilitated the dominance of corystosperms in wide geographical area Scotese, 1999, McLoughlin, 2001). ...
... But, Kerp et al. (2006) and Hamad et al. (2008) have reported Dicroidium in association with Cathaysian elements from the Upper Permian of Jordan. Chatterjee et al. (2013) opined that possibly the corystosperms may have originated in the equatorial region during the late Permian and subsequently during the Triassic they became widespread in the southern hemisphere. ...
The macroflora of the Parsora Formation is unique in terms of its diversity and comprises a diverse array plant groups. Variety of plant macrofossils having affinities with pteridophytes, pteridosperms and gymnosperms have been reported and described earlier from the Parsora Formation since the last phase of 19th century. However, affinities and identification of some of the taxa reported earlier from the Parsora Formation namely, Neocalamites foxii Lele, Cladophlebis sp. cf. C. denticulata Lele, Taeniopteris ?spatulata McCelland, Desmiophyllym indicum Sahni, Biera indica Lele species of Araucarites have been questioned earlier by a number of workers. The most commonly occurring macrofossil of the Parsora Formation is Dicroidium, the age-diagnostic Triassic marker taxon. In the present study, a number of species of Dicroidium described earlier have also been thoroughly reassessed. The age of the Parsora Formation is controversial from the biostratigraphic point of view and this controversy is yet to be resolved. Earlier, based on the occurrence of Estheriella, an Early Triassic age had been assigned for the Parsora Formation; however, evidences of plant macrofossils and palynofossils indicate a younger age. It may be mentioned here that some plant macrofossils having Late Permian and Early Triassic affinities were reported earlier from the so called Parsora Formation. This created more controversy for the age connotation of the formation. The present contribution is focussed to revise and reassess the macroflora of this lithounit and to resolve the age of the Parsora Formation based on both biostratigraphy and lithostratigraphy. Correlation with the Triassic macroflora known from other parts of the world has also been done.
... Townrovia is rare and has only been identified from the Middle and Upper Triassic of Tasmania, New Zealand and Antarctica Chatterjee et al., 2013). Based on the occurrence of specimens at the same Antarctic Upper Triassic locality, Bomfleur et al. (2011) associated Townrovia with Matatiella and Dejerseya; they ranked these with the Peltaspermales based on structural similarity. ...
Pteridosperms are preserved abundantly in the Gondwanan Triassic, with many species exhibiting considerable morphological variation that has been attributed to a hybridization model of speciation. This is an improbable explanation given that hybridization is very rare in gymnosperms. Allopatric speciation resulting from geographic and climatic provincialism is a more likely explanation for the morphological diversity which is well represented in Anisian–Norian (Middle and Upper Triassic) floras of Australasia and elsewhere in Gondwana. Most specimens are distributed among three families: Umkomasiaceae, Peltaspermaceae and Matatiellaceae. These families, together with other possibly pteridospermous genera, are reviewed herein. Diversity in these families apparently declined by the Rhaetian and they did not persist into the Gondwanan post-Triassic. Australasian post-Triassic strata contain remarkably different floral assemblages to those of the Triassic. No fructifications are clearly pteridospermous and no remains show any obvious relationship with pteridosperms of the Gondwanan Triassic. Caytonialean fructifications are not known in Australasian strata; however, associated foliage has been reported from the Eastern Gondwanan Upper Triassic through Middle Jurassic including Australia. Much fern-like foliage, claimed to be pteridospermous from the Lower Jurassic through Eocene of Eastern Gondwana, lacks supporting evidence of such affiliation. © 2015, Instituto Geologico y Minero de Espana. All rights reserved.
... Member C is highly fossilifer- ous. A rich Dicroidium flora has been described recently from the Lashly Formation ( Chatterjee et al., 2013) and the evidence of ancient forest fire from microscopic charcoal remains has been reported by Kumar et al. (2011). Much of the Member D is missing from Allan Hills. ...
The Permo-Triassic Victoria Group in South Victoria Land, Antarctica, is a heterogeneous sequence of glacial tillite beds, carbonaceous and non-carbonaceous fluvial deposits, and volcaniclastic strata. The carbonaceous beds are rich in plant fossils associated with coal seams. In Antarctica, the geological record of the Late Paleozoic Ice Age is restricted to the Early Permian. After deglaciation, the Glossopteris flora thrived in polar forests in Antarctica throughout the Permian but disappeared at the end-Permian extinction. Here we describe the first comprehensive record of the Glossopteris flora from the Permian Weller Formation of Allan Hills, South Victoria Land, Antarctica. The flora is well preserved and comprises pteridophytes and gymnosperms. The pteridophytes include the sphenopsid order Equisetales and the gymnosperms comprise Glossopteridales. Equisetales are represented by branched and unbranched axes, whereas, Glossopteridales are highly diverse encompassing Gangamopteris, Glossopteris, Surangephyllum, sterile scale leaves namely Scirroma sp., Nautiyalolepis sp., Utkaliolepis indica, Scale leaf A and scale leaf of male fructification Eretmonia. The flora of the Weller Formation shows close similarity with the Late Permian assemblages of India, South Africa and Australia. Gangamopteris, an index fossil of the Early Permian formations of different Gondwana continents, had extended stratigraphic range in the Late Permian Weller Formation of Allan Hills. Antarctica played a crucial role in the dispersal of Glossopteris flora because of its central position in Gondwana.
