A New High-Paleolatitude Late Permian Permineralized Peat Flora from the Sydney Basin, Australia

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A NEW HIGH-PALEOLATITUDE LATE PERMIAN PERMINERALIZED PEAT FLORA FROM THE SYDNEY BASIN, AUSTRALIA

Stephen McLoughlin,1,* Anton Maksimenko,† and Chris Mays*

*Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, S-104 05 Stockholm, Sweden; and †Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia

Guest Editor: Alexandru M.F. Tomescu

Premise of research. Permineralized peats are prized for hosting three-dimensionally preserved plant remains that provide insights into fossil plant anatomy and the composition of coal-forming ecosystems. A new record of siliceous permineralized peat is documented from a Lopingian-aged (upper Permian) strata from the southern Sydney Basin. It represents the fifth Permian permineralized peat identified from eastern Australia. Methodology. The single permineralized peat block was cut into smaller blocks, and both cellulose acetate peels and standard thin sections were prepared for study using transmitted light microscopy. Quantitative analysis of the peat was carried out using point counts perpendicular to bedding. One block examined using synchrotron X-ray computed tomography (CT) revealed the three-dimensional anatomy of abundant fossil seeds. Pivotal results. The peat contains a plant assemblage dominated by glossopterid leaves, seeds, and axes; although degraded, probable pteridophyte remains represent a significant subsidiary component of the assemblage. A new leaf form (Glossopteris thirroulensis McLoughlin et Mays sp. nov.) and a new type of seed (Illawarra- spermum ovatum McLoughlin et Mays gen. et sp. nov.) are described. Leaf-, wood/seed-, and fine detritus-rich organic microfacies with gradational boundaries are evident within the peat. Conclusions. Regular growth rings in the small permineralized axes, together with the occurrence of autumnal mats of glossopterid leaves, signify a strongly seasonal climate. The presence of abundant charcoal in the peat indicates that fire was a significant influence on the high-paleolatitude mire ecosystem. Differentiation of organic microfacies within the peat profile indicates subtle variation in the contribution of plant components to the peat through time. The absence of mineral grains in thin section and CT, together with the presence of authigenic sulfides, indicates accumulation of organic matter in a stagnant mire away from the influence of clastic input.

Keywords: Glossopteris, Lopingian, ﬁre, peat-forming ecosystems, seasonality, taphonomy, plant anatomy.

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Introduction Gondwanan flora. Rare blocks of Lopingian silicified peat are also known from China (Tian et al. 1996). Many of these peat Siliceous permineralized peats of Lopingian (late Permian) age deposits are associated with ash-fall tuffs sourced from felsic to are known from several sites within foreland basins along the intermediate volcanism that developed along the convergent eastern margin of Gondwana (Schopf 1970; Gould and Dele- Panthalassan margin of Gondwana and Cathaysia at the end voryas 1977; Taylor et al. 1989; Pigg and McLoughlin 1997; of the Paleozoic (Veevers 2000). These deposits are prized for Decombeix et al. 2010). An isolated middle Permian siliceous hosting exceptional three-dimensionally preserved plant fossils permineralized peat deposit is also known from the intracratonic that help elucidate the anatomy, physiology, and autecology of Lambert Graben (Prince Charles Mountains: McLoughlin and the entombed vegetation, together with providing insights into Drinnan 1997; Holdgate et al. 2005), Antarctica, then located interactions with fungi and terrestrial arthropods (Kellogg et al. in central Gondwana. A further occurrence of Permian permin- 2004; Slater et al. 2012, 2015; Harper et al. 2013). The per- eralized peat or leaf litter occurs in the Parnaíba Basin of mineralized fossils also provide insights into the organic northern Brazil (Tavares et al. 2014), but this deposit lacks connections between normally isolated plant organs, and the Glossopteris and falls outside the distribution of the classical contents of entombed microsporangia yield information on the intraspecific variability of normally dispersed spores and pollen. The onshore Sydney Basin of eastern Australia (fig. 1A) hosts 1 Author for correspondence; email: [email protected]. a 14500-m-thick Permian-Triassic mixed marine and fluvial Manuscript received November 2018; revised manuscript received January succession that locally hosts world-class bituminous coal re- 2019; electronically published June 5, 2019. sources (Agnew et al. 1995; Tadros 1995). Lopingian strata of

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Fig. 1 Locality and stratigraphic details of the studied permineralized peat block. A, Map of eastern Australia showing the major Permian basins. B, Thirroul area locality map showing the distribution of rock units. C, Lithostratigraphic scheme for the Sydney Basin in the Thirroul area. Star indicates approximate geographic and stratigraphic position of the studied sample. the southern Sydney Basin, assigned to the Illawarra Coal 1997). The single transported cobble in that study was proba- Measures, host rich adpression plant fossil assemblages, but bly sourced from the Lopingian Illawarra Coal Measures in few systematic surveys of the floras have been undertaken (Rigby the bank of Katoomba Creek (Jamison Valley) roughly 2.4 km 1964; Retallack 1980; Shi and McLoughlin 1997). Thus far, south of the Three Sisters at Katoomba, in the western Sydney there has been only one previous report of permineralized peat Basin, in New South Wales. Individual transported and in situ in Permian strata of the Sydney Basin (Pigg and McLoughlin silicified woody stumps and logs, and cherty tuffaceous beds MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 515 with leaf impressions, are relatively common in Lopingian aviewareaof∼15 mm # 13 mm at the zoom tuned for 5.97 mm. strata throughout the basin (Etheridge 1894, 1899; Diessel With this setup, optimal exposure was 0.27 s long. 1985). On this basis, there are strong prospects that additional For projection contrasting and noise reduction, signal maxima Permian silicified peat deposits will come to light elsewhere in and minima were acquired by collecting 100 background images the Sydney Basin. (no sample in the beam) and 100 dark-field images (beam is off), Here we document one such case of a transported cobble of respectively. A sample-to-detector distance of 40 cm was em- siliceous permineralized peat probably derived from Lopingian ployed to enhance the image with propagation-based phase con- strata of the southern Sydney Basin. The peat contains a range trast, which improves the material differentiation. Postprocess- of anatomically preserved plant fossils, which are systematically ing consisted of the steps that follow: (1) clean background and described in this study. We also contrast the composition of the dark-field images were formed as the median of all 100 repeats, new peat sample with examples described previously from the which were then applied to each of the 1800 sample images Sydney and Bowen basins in Australia and the Transantarctic (p[sample 2 dark field]/[background 2 dark field]); (2) light Mountains and Prince Charles Mountains in Antarctica. noise was suppressed applying Zinger’s filter to all input images; Permineralized peats are especially significant in that they (3) phase retrieval and ring artifact suppression algorithms were preserve the three-dimensional architecture of the mass of or- applied; (4) the stack of horizontal cross-sections comprising ganic matter that contributed to the formation of coal. Adpression the volume were produced using the standard filtered-back pro- assemblages are typically preserved in clastic-rich flood basin jection algorithm; and (5) 3-pixels cube averaging of the resul- deposits and do not necessarily provide an accurate representa- tant volume was conducted to reduce noise. Reconstructions tion of the coal-forming plant community. Petrographic analyses were performed with the MASSIVE (Multimodel Australian of bituminous coals can provide useful quantitative information Sciences Imaging and Visualisation Environment) supercom- on the range of plant tissue types contributing to the organic ac- puter cluster based in Clayton, Victoria, Australia. Different cumulation, but it is usually impossible to identify specificplant software packages were employed for the above stages of data taxa or organs in such studies. Here we provide a simple quanti- processing, including Fiji, X-tract, and ImageMagick. Three- tative survey of the major constituents of the permineralized peat dimensional rendering and visualizations were conducted on and their distribution within the matrix. three specimens (F92048k internal seed specimens A–C) with the Avizo software package (9.5.0, ThermoScientific). Material and Methods Quantitative assessments of peat microfacies content were undertaken using a point method modified from Mackowsky (1982). Asilicified (permineralized) block of peat measuring ∼5cm# Transects across 14 thin sections cut perpendicular to peat bed- 5cm# 10 cm was found at Thirroul Beach in the Illawarra dis- ding were point-counted at increments of 250 mm for a total of trict of New South Wales (fig. 1B) by Alex Szakaly some time 1753 data points. Peat components were assigned to the taxo- prior to 1994. The block was donated to the collections of the nomic and plant organ groups described below. Tissues within Australian Museum in Sydney and registered under the number organs (e.g., the epidermis, mesophyll, and vascular strands of AMF92048. The block was subsequently cut into smaller pieces, leaves) were not differentiated. Inter- and intracellular spaces each labeled with a lowercase letter suffix, and thin sections and within tissues were counted as part of the host organ. Cement- cellulose acetate peels were prepared from various blocks and la- filled pore and fracture spaces between discrete constituent par- beled with an additional numerical suffix(21, 22, etc.). At the ticles in the peat were assigned to the category of “silica-filled School of Earth Sciences, University of Melbourne, standard thin voids.” sections were prepared to thicknesses of 30–40 mm to obtain optimal clarity of cell structures according to the methodology of Geological Setting Galtier and Phillips (1999). Cellulose acetate peels were prepared following the procedures of Hass and Rowe (1999), with surfaces The studied silicified peat block was found as a loose cobble etched in 48% hydrofluoric acid for 60 s, dried, then bonded to at Thirroul Beach (lat. 3471904400S, long. 15075503400E; fig. 1B), 50-mm-thick cellulose acetate sheets using acetone. Portions of located 12 km north of Wollongong and 57 km southwest of acetate peels were cut and mounted on glass slides under a cover- central Sydney in the southern Sydney Basin. Outcrops at the slip in Histomount (National Diagnostics). Photomicrographs southern end of Thirroul Beach expose the ichnofossil-rich shal- were taken with an Olympus BX-51 compound transmitted light low neritic to deltaic Erins Vale Formation, representing the up- microscope and an Olympus SZX10 stereomicroscope, each permost unit of the Guadalupian-aged Cumberland Subgroup of equipped with an Olympus DP-71 digital camera. the Illawarra Coal Measures (fig. 1C). This unit is capped by a X-ray synchrotron computed tomography (CT) scan data on regional unconformity marking the Guadalupian–Lopingian hand sample F92048k were acquired at the Imaging and Med- transition and is overlain by the Wilton Formation of the Sydney ical Beamline (IMBL) of the Australian Synchrotron in Clayton, Subgroup (the uppermost subgroup of the Illawarra Coal Mea- Victoria, Australia. X-ray photon energy of 30 keV was em- sures; Bamberry 1991; fig. 1C). ployed for the experiment, and CT data acquisition consisted The lower Wilton Formation exposed at the southern end of 1800 projections with a total scan arc of 1807. The images of Thirroul Beach consists of planar and trough cross-bedded were recorded using IMBL’s Ruby detector equipped with a lenticular sandstones and granule conglomerates broadly fining 20-mm-thick Gadox scintillator, which converts the X-ray photons upward into interlaminated fine-grained sandstones and silt- into visible light, which is reflected by a silicon mirror and cap- stones and ultimately to the interlaminated coal and shale of tured by a pco.edge sCMOS camera with a Nikon 150-mm lens. the Woonona Coal Member (Shi and McLoughlin 1997). Nu- The detector produces images 2560 # 2180 pixels in size that give merous scour and lateral accretion surfaces of the lower Wilton 516 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Formation are evident in outcrop, and siltstone-dominated component of the cortex consists of relatively thick-walled cells packages typically contain abundant plant debris, much of which ~5–10 mm in diameter. The outer surface of the axis is irregularly appears to have been charcoalified. Several of the sandstone compressed, and no leaves are discernible. bodies host permineralized or coalified logs, and rounded cobbles A single ill-preserved megaspore was identified in thin sec- and pebbles of equivalent permineralized wood are common tions of the peat (fig. 2B). It is heavily compressed and contorted in the adjacent modern beach sediments at this locality. The with a maximum dimension of 705 mm. It has a spongy wall upward-fining profile of the lower Wilton Formation, its facies ~50 mm thick. Laesurae, exine sculpture, and intine are not relationships, fossil content, and array of sedimentary struc- discernible. tures, suggests that this part of the succession was deposited Remarks. The small axis is tentatively assigned to Lycopsida mainly within meandering fluvial settings with a dominant north- based on its protostelic architecture and pervasively pitted large easterly paleocurrent orientation (Bamberry 1991; Shi and Mc- central tracheids that bear similarities to herbaceous Pauroden- Loughlin 1997). dron axes from the Permian of Antarctica (McLoughlin et al. The upper Wilton Formation exposed on headlands at the 2015). Both ligulate and eligulate herbaceous lycophyte axes northern end of Thirroul Beach, and along beaches further to are known from Permian strata in eastern Gondwana (Townrow the north, is dominated by thinly interbedded lenticular ripple- 1968; Schwendermann et al. 2010; McLoughlin et al. 2015) and marked fine-grained sandstones and bioturbated carbonaceous appear to have been significant components of the understratum siltstones. These deposits reflect a return to lower delta plain and of glossopterid-mire vegetation. shallow marine (interdistributary bay) sedimentation (Bamberry Dispersed lycophyte megaspores are abundant and diverse 1991). throughout the Permian of Gondwana (Bharadwaj and Tiwari Given the relatively large size of the studied cobble, only 1970; McLoughlin et al. 1997; Glasspool 2000, 2003; Ricardi- moderate rounding of its margins, and the common occurrence Branco et al. 2002; Slater et al. 2011) and are also subsidiary of silicified wood in the lower Wilton Formation, we infer this components of Carboniferous and Triassic permineralized peats unit to be the most probable source of the silicified peat block. (Willard et al. 1995; McLoughlin and Strullu-Derrien 2016). The No studies have specifically investigated the paleontology of the specimen documented in this study appears to lack any signifi- Wilton Formation, although McMinn (1985) mentioned the cant ornamentation, and it is too compressed and degraded for presence of the index spore taxon Dulhuntyispora parvithola adequate identification. in the lower part of this unit, signifying a Lopingian age (Laurie et al. 2016). Metcalfe et al. (2015) reported high-precision chem- Class—?Filicopsida ical abrasion isotope dilution thermal ionization mass spec- trometry (CA-TIMS) U-Pb zircon dates of 254.86 5 0.30 Ma Putative Fern Axes and Foliage for a tuff from the Huntley Claystone Member of the Bargo Clay- stone resting above the Wilton Formation. Furthermore, Huys- Material. Thin, ill-preserved permineralized leaves and kens (2014) reported a CA-TIMS U-Pb zircon date of 258.89 5 crushed axes/rachises attributed tentatively to ferns are preserved 0.89 Ma from the Erins Vale Formation underlying the Wilton in most slides. The best preserved examples occur in slides AM Formation. Thus, the Wilton Formation can be bracketed to the F92048b-6, F92048j-1, and F92048k-1. Wuchiapingian stage (early late Permian). Description. Ferns are possibly represented in the peat by strongly compressed protostelic axes (fig. 2C–2E). These axes are 0.5–1 mm wide in the plane of compression (parallel to bed- Results ding). They have a central terete stele ~150 mm in diameter composed of a core of dense, thick-walled tracheids only 3–5 mmin The fossil content of the permineralized peat is described be- diameter, in some cases surrounded by a zone of more reg- low according to taxonomic group and the representation of or- imented cells ~15 mm in diameter (fig. 2C). The surrounding gan types. This is followed by a quantitative assessment of the cortical tissues are typically degraded or heavily stained by peat constituents. opaque matter but locally incorporate cells up to 35 mmindi- ameter. In some cases, the cortex appears to have been differen- Class—Lycopsida (Fig. 2A, 2B) tiated into an inner, more readily degraded, zone and an outer zone of slightly more robust cells (fig. 2C,2D). A dark brown or Lycopsid Axis and Megaspore opaque epidermal rind is commonly present (fig. 2E). Charcoalified primary xylem fragments composed of tracheids Material. Slides AM F92048g-1 and F92048d-3. 3–20 mm wide with broad scalariform pitting are scattered Description. A single possible herbaceous lycophyte axis through the peat (fig. 2F,2G). Transverse bars comprising the is preserved in the sample. It is represented by the cross-section tracheid wall are !1 mmthick. of a significantly compressed protostelic stem of which mainly Associated with the putative fern axes are layers of matted, the central stele is preserved, along with some degraded cortical thin, laminar structures, here interpreted to represent fern leaves tissue (fig. 2A). The axis is ~0.5 mm wide in the plane of com- and rachises. These structures have very poor anatomical preser- pression. The central stele is 180 mm wide in this plane. The stele vation and consist of what appears to be an inner tissue of spongy consists of heavily pitted tracheids with diameters ranging from cells ~20 mm in diameter surrounded by a single layer of epider- 33 mm in the center to 15 mm at the margins. Whether the stele mal cells 5–10 mm in diameter. These laminar structures are up to was originally stellate or circular in cross-section cannot be de- 5 mm wide; they are generally 20–80 mm thick but are locally termined, owing to substantial compression. The preserved thickened to 150 mm in the center (fig. 2H–2L). Fig. 2 Possible lycophyte and fern remains within the silicified peat. A, Possible crushed lycophyte axis in transverse section retaining central xylem tissue; AMF92048g-1. B, Crushed megaspore in oblique section; AMF92048d-3. C, Small protostelic axis in transverse section with broad cortex; AMF92048k-1. D, Compressed protostelic axis or rachis in transverse section; AMF92048k-1. E, Compressed protostelic axis with thick cortex; AMF92048k-1. F, G, Charcoalified tracheids with scalariform to reticulate thickenings; AMF92048b-6. H, Putative fern pinnule in transverse section; AMF92048j-1. I, Putative fern pinnule in transverse section with midrib thickening; AMF92048k-1. J, Enlargement of midrib region from I. K, Matted thin probable fern pinnules in transverse section; AM F92048k-1. L, Matted and distorted thin probable fern pinnules in transverse section; F92048j-1. Scale bars: A, D p 50 mm; B, C, E, J–L p 100 mm; F, G p 20 mm; I p 200 mm. 518 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Remarks. The identification of these remains as ferns is of degraded roughly cubic epidermal cells is present, each 10– equivocal. They lack the anatomical details for confident as- 15 mm in diameter. Stomatal details are not preserved. signment to any particular fern group. Nevertheless, they are Remarks. Paradermal sections were not available to deter- abundant in the peat and ought to represent one of the common mine the venation pattern of this leaf. Nevertheless, in cross- plant groups known from compression floras elsewhere in the section it has characters consistent with the diagnosis of Glos- Sydney Basin. The lamina widths are generally too great to rep- sopteris schopfii Pigg 1990. Of particular significance are the resent the needle-like leaves of the common sphenophytes (Phyl- prominent vascular bundle sheaths and the mesophyll that is lotheca and Lelstotheca) represented in the local floras (Rigby not differentiated into clear palisade and spongy layers. Minor 1966; Holmes 1995; Shi et al. 2010), and the presence of vascular differences are apparent from the type material of G. schopfii, tissues in the axes negates assignment to the bryophytes. Anatom- including a slightly lesser laminar thickness, smaller phloem la- ically preserved mosses assigned to Merceria augustica Smoot cunae, and the absence of a thin hypodermis in the Thirroul et Taylor 1986b from the Permian of Antarctica differ from specimen. It is likely that these features are within the normal the Thirroul Beach plants in that most of the leaf is one cell range of intraspecific variation and might also have been influ- thick, only thickening to around 5–10 cells in the midrib. The enced by a greater degree of compaction in the Thirroul spec- laminar structures most likely represent fern pinnules, with cen- imen. The lack of prominent palisade development in the meso- tral thickenings representing the position of the midvein. Fern fo- phyll suggests that these leaves might have been understory or liage is abundant, although of low diversity, in Australian Perm- shade leaves. ian adpression floras and commonly occurs in dense mats (Gould Schwendemann (2012) suggested that glossopterids may – 1970; Rigby 1972; Holmes 1995; McLoughlin 1993). Dispersed have independently developed transitional C3 C4 physiology. filicalean spore suites are considerably more diverse in Austra- There is a superficial similarity between the prominent bundle fi lian Permian strata than the macrofossil suites (Balme and Hen- sheaths of G. schop i (and conferred forms) and modern C4 nelly 1956; Helby 1973; Foster 1979) and suggest that ferns were plants with Kranz anatomy. However, the sheath cells of mod- major components of the forest understory. Metaxylem tracheids ern plants with Kranz anatomy tend to be significantly larger of Palaeosmunda species documented from Guadalupian– and less numerous (Muhaidat et al. 2007) compared with the Lopingian strata of northeastern Australia have scalariform pit- thick-walled narrow fibers forming the bundle sheaths of G. ting that is similar to that of the charcoalified fragments illus- schopfii and its allies. Bundle sheaths in Glossopteris might trated here (fig. 2F,2G; Gould 1970; McLoughlin 1992). have been specific adaptations for strengthening of a broad lamina or for hindering vein-fluid feeding by insects. Glossopteris schopfii and forms closely comparable to that Class—Dictyopteridiopsida species have been reported from Lopingian strata of the Trans- antarctic Mountains in Antarctica and the central Bowen Basin Glossopterid Leaves and central Sydney Basin in Australia (Pigg 1990; Pigg and Mc- Loughlin 1997). The nearest deposits reported previously that Genus—Glossopteris Brongniart 1828 ex Brongniart 1831 contain this species are in the Illawarra Coal Measures near Ka- toomba, ~85 km to the northwest of Thirroul Beach. Species—Glossopteris schopfii Pigg 1990 (Fig. 3O, 3P) Species—Glossopteris homevalensis Pigg et Material. A single specimen in slide AM F92048d-4. McLoughlin 1997 (Fig. 3A–3N, 3Q) Description. The only available specimen is the transverse section of the central portion of an anatomically preserved leaf Material. Numerous leaves of this species occur through- of indeterminate width. The leaf is ~200 mm thick and tapers out the peat block. The best preserved specimens are available only gently in thickness away from the midrib. The midrib re- in slides AM F92048i-1, F92048b-2, F92048b-3 TS, F92048b-5, gion contains four or five discrete vascular bundles up to 50 mm F92048b-6, F92048b-8, F92048b-11, F92048b-12, F92048d-1, thick and 120 mmwide(fig. 3O). F92048d-3, F92048g-3, F92048g-8, F92048j-1, and F92048k-1. The vasculature is mesarch with a very small cluster of proto- Description. These anatomically preserved leaves have re- xylem strands surrounded by 3–5 layers of metaxylem tracheids; ticulate venation with apparently narrow (150–200 mm wide) no obvious secondary xylem is developed. The regions of phloem areolae based on the few fragments observed in paradermal sec- in each bundle are represented by compressed lacunae. A prom- tions (fig. 3L,3Q). The leaves range from 150 mm to 200 mmthick inent vascular bundle sheath is present and consists of 2–4layers near the lamina margins to 500 mm thick at the midrib. The midrib of thick-walled (5 mmthick)fibers with circular to polygonal lu- region contains up to six discrete vascular bundles, each up to mina 15–30 mm in diameter. In the midrib region, adjacent vas- 160 mm thick and generally 150–200 mm wide but locally reach- cular sheaths merge in some cases (fig. 3P). Fibers are absent else- ing 640 mmwide(fig. 3A–3K). Immature leaves are retained in where in the leaf. flattened spiral clusters in some cases (fig. 3M). The adaxial side of the mesophyll consists of circular to ob- The vasculature is mesarch with 4–6 protoxylem strands sur- long cells, 40–70 mm in maximum dimensions. These cells are rounded by multiple layers of metaxylem; secondary xylem up larger than those on the abaxial side of the mesophyll but do to seven cells thick is locally developed, especially in bundles not form a distinctive palisade layer. Abaxial mesophyll cells located in the midrib region (fig. 3D,3H,3K). Tracheids in the are lenticular, up to 40 mm wide, and only 10 mm tall (although vascular bundles have tight annular or helical wall thickenings their slender shape might be due to compression). A single layer (fig. 3J,3N). Phloem cells are crushed or degraded beyond Fig. 3 Leaves of Glossopteris homevalensis Pigg et McLoughlin 1997 (A–N, Q) and Glossopteris schopfii Pigg 1990 (O, P). A, C, Trans- verse section of strongly compressed leaf with small vascular strands; AMF92048b-5. B, Details of lateral vascular strands in transverse section; AMF92048d-3. D, Midrib vascular strands in transverse section; AMF92048b-8. E, Transverse section of leaf with seven vascular strands; AMF92048b-2. F, Details of vascular bundles; AMF92048b-3. G, Portion of a leaf with small vascular bundles; AMF92048d-1. H, Broad vascular bundles in leaf midrib; AMF92048g-5. I, Lateral veins in transverse section; AMF92048d-3. J, Longitudinal (paradermal) section of lateral vein; AMF92048b-1. K, Broad midrib vascular strands surrounded by predominantly spongy mesophyll; AMF92048i-1. L, Paradermal section of leaf showing polygonal mesophyll cells between veins; AMF92048j-1. M, Transverse section of apical bud of unexpanded leaves; AMF92048g-8. N, Oblique section of vascular strand showing tracheids with annular thickenings; AMF92048j-1. O, P, Transverse section of midrib region showing local amalgamation of prominent vascular sheaths; AMF92048d-4. Q, Paradermal section showing cross-connection between lateral veins; AMF92048b-2. Scale bars: A, E p 200 mm; B, C, I, P, Q p 50 mm; D, F–H, J–M, O p 100 mm; N p 20 mm. 520 INTERNATIONAL JOURNAL OF PLANT SCIENCES recognition and commonly represented by a thin zone of brown Additional material. This is the most abundant leaf type in the staining. A vascular bundle sheath is either weakly developed block of silicified peat from Thirroul Beach. The best-preserved (only 1–2 cells thick) or absent. Small clusters of fibers are devel- specimens are available in slides AM F92048i-1, F92048k-2, oped in the adaxial mesophyll above the midrib vascular bundles F92048b-1, F92048b-2, F92048b-3 TS, F92048b-5, F92048b-6, of large leaves (fig. 3K). F92048b-7, F92048b-8, F92048b-11, F92048b-12, F92048d-1, The adaxial side of the mesophyll consists of a spongy to F92048d-2, F92048d-3, F92048d-4, F92048g-1, F92048g-2, weakly developed palisade layer comprising cells 15–50 mmin F92048g-3, F92048g-5, F92048g-7, F92048g-8, F92048j-1, and diameter and 20–100 mm tall (fig. 3B,3D,3E,3I). The abaxial F92048k-1. mesophyll is a spongy layer consisting of roughly equidimen- Etymology. The species is named for its source locality sional cells 15–70 mm in diameter, with slightly sinuous walls (Thirroul Beach). (fig. 3C,3G,3I,3K). Epidermal cells are generally ill preserved Diagnosis. Reticulate-veined leaves with narrow meshes, a and 15–25 mm in diameter. Stomatal details are not preserved. single-celled dermal layer, midrib composed of around four vas- A weakly defined hypodermis 1–2 cells thick is developed in the cular bundles, and marked differentiation of the adaxial and midrib region of some specimens (fig. 3C). abaxial mesophyll. Vascular bundles circular to rhombic in Remarks. These leaves conform in most respects to the cross-section, consisting of mesarch primary xylem with annu- description of Glossopteris homevalensis given by Pigg and lar to helical thickenings, minimal secondary xylem develop- McLoughlin (1997). The Thirroul Beach leaves differ only ment, thin-walled abaxial phloem, and fiber-bundle sheath that in the slightly greater size ranges of their lamina and vascular extends as columns through the adaxial and abaxial mesophyll. bundles, which we interpret to represent normal intraspecific Adaxial side of mesophyll represented by a prominent palisade variation. Since leaves are not exposed on the surface of the layer; abaxial side characterized by a spongy layer. Wedge of block, large paradermal sections were not obtainable, and fibers filling the mesophyll along the leaf margin. epidermal features are poorly preserved, it is not possible to Description. These anatomically preserved reticulate-veined compare the detailed venation characters and stomatal fea- glossopterid leaves have narrow areolae (fig. 4I;200–400 mm tures with the type material, which derives from equivalent- wide on the lamina, ~100 mm wide in the midrib). The leaves aged strata in the northern Bowen Basin ~1650 km to the range from 150 mm to 250 mm thick near the lamina margins north. to 500 mm thick at the midrib. The midrib region contains up Only two other species of anatomically preserved Glossopteris to four discrete vascular bundles, typically elliptical to rhombic leaves have been defined formally. Of these, G. schopfii (Pigg in cross-section, each up to 150 mm thick and generally 150– 1990), known from Lopingian strata of the Transantarctic 200 mmwide(fig. 4G,4H). Vascular bundles are smaller (~80– Mountains in Antarctica, and the Sydney and Bowen basins 100 mm in diameter) near the margins (fig. 4B,4D,4F). in Australia, differs most notably by the presence of robust mul- The vasculature is mesarch with 4–8 protoxylem strands en- tilayered fiber sheaths surrounding the vascular bundles. Glos- compassed by multiple layers of metaxylem; secondary xylem is sopteris skaarensis Pigg 1990 and conferred specimens are known developed minimally (up to three cells thick) and generally rep- from equivalent strata of the same regions as G. schopfii and resented only in bundles located in the midrib region (fig. 4G,4H). can be distinguished from G. homevalensis most notably by their Tracheids in the vascular bundles have tight annular or helical wall robust and strongly regimented hypodermal cell layers on both thickenings (fig. 4J). Phloem cells are generally crushed or degraded abaxial and adaxial sides of the mesophyll. Secondary xylem is but may be locally represented by a few thin-walled cells. especially well developed in the midrib of some G. homevalensis A vascular bundle sheath 1–3 fiber cells thick is developed locally leaves such that individual vascular strands amalgamate (fig. 3F, (fig. 4H). Fibers are 5–8 mm in diameter. A column of longitudi- 3H,3K). However, all anatomically preserved Glossopteris and nally aligned fibers extends beyond the bundle sheath adaxially Noeggerathiopsis leaf species possess some secondary xylem, and abaxially to the epidermis (fig. 4B,4E,4F). The leaf surface particularly in the midrib (Pigg 1990; McLoughlin and Drinnan is commonly indented on the adaxial surface over these fiber 1996; Pigg and McLoughlin 1997); hence, this feature does not columns (fig. 4B,4D–4F). appear to be a useful character for specific or generic delimita- The adaxial side of the mesophyll consists of a well-developed tion. The new record extends the geographic range of G. home- palisade layer 1–2 cells thick (fig. 4A,4C). Palisade cells are typ- valensis to Lopingian strata of the Sydney Basin. This geographic ically 30–60 mm in longitudinal diameter, 80–180 mm in trans- range is not unexpected given that the Bowen and Sydney basins verse diameter, and 70–150 mm tall. The abaxial mesophyll is are part of the same foreland basin complex and were occupied spongy (fig. 4A–4E) and consists of roughly equidimensional by a common drainage system late in the Permian (Fielding et al. cells 30–80 mm in diameter, with slightly sinuous walls. Epider- 2000). mal cells are brick shaped, 20–50 mm wide, and !15 mm tall. Stomatal details were not identifiable. A hypodermis is not de- Species—Glossopteris thirroulensis McLoughlin veloped, but a wedge of 15–20 mm diameter fibers fills the entire et Mays sp. nov. (Fig. 4A–4J) mesophyll space up to 220 mm inward from the tapered leaf margin (fig. 4F). Holotype. Leaf illustrated from slide AM F92048b-2 (fig. 4E); Remarks.Thefiber bands abutting the vascular strands are a here designated. key feature of the new species. Northern Hemisphere Cordaites Type locality, unit, and age. Thirroul Beach (loose cobble); leaves commonly possess columns of horizontal fibers traversing probably derived from the lower Wilton Formation, Sydney the mesophyll between and abutting the vascular bundles (Good Subgroup, Illawarra Coal Measures; Wuchiapingian (early late and Taylor 1970). Gondwanan cordaitalean leaves (Noeggera- Permian). thiopsis) are similar in size, shape, and thickness to Glossopteris Fig. 4 Glossopteris thirroulensis sp. nov. leaves. A, Longitudinal section showing marked differentiation of palisade and spongy mesophyll; AMF92048d-1. B, Transverse section of leaf with fibers stacked abaxial and adaxial to vascular strands; AMF92048d-1. C, Longitudinal section showing prominent palisade layer in the mesophyll; AMF92048b-7. D, Transverse section of leaf; AMF92048d-4. E, Transverse section of leaf with fibers stacked abaxial and adaxial to vascular strands; AMF92048b-2 (Holotype). F, Transverse section of leaf margin showing fibers in margin of mesophyll; AMF92048i-1. G, Transverse to oblique section of leaf midrib; AMF92048i-1. H, Transverse section of leaf midrib; AMF92048b-3. I, Paradermal section of leaf showing vein division and broad mesophyll cells; AMF92048k-1. J, Enlargement of vein in I containing tracheids with annular thickenings. Scale bars: A, B, E–G, I p 100 mm; C, D, H, J p 50 mm. 522 INTERNATIONAL JOURNAL OF PLANT SCIENCES leaves but differ in lacking vein anastomoses and having promi- Description. Noncharcoalified axes with secondary growth nent stomatal furrows and trichomes on the abaxial surface are relatively common in the peat block where they occur, espe- (McLoughlin and Drinnan 1996). They lack the prominent fiber cially in seed- and leaf-rich microfacies. The axes are consistently bands of Northern Hemisphere cordaitaleans. thin (!9 mm in diameter) and incorporate 1–14 seasonal growth Glossopteris thirroulensis McLoughlin et Mays sp. nov. rep- increments (fig. 5A,5B,5G). A limited range of primary tissues is resents the fourth formally defined, anatomically preserved spe- preserved in some specimens; these tissues are commonly not pre- cies of this genus. Owing to a lack of leaves exposed on the sur- served or strongly degraded in other specimens. face of the block and the availability of only a few paradermal The pith is circular to slightly stellate in cross-section (fig. 4B). sections, a full description of the venation pattern is not possi- It reaches 3.5 mm wide and consists mostly of degraded spongy ble. Pigg and McLoughlin (1997) summarized the morpholog- cells encompassing patches of sclerenchyma (fig. 5A,5B). These ical and anatomical characters of Glossopteris species described patches range from small clusters, ~500 mm in diameter, to large previously from permineralized peats. The new species differs wedges or partitions, up to 0.8 mm # 3.0 mm. They occur at reg- from forms described previously and from other silicified leaves ular intervals along the stem to give the pith a segmented architec- in the same peat block most notably by the (1) prominence of ture (fig. 5C). Individual sclereids are polygonal and roughly the palisade layer on the adaxial side of the mesophyll, (2) pres- equidimensional (diameters of 50–60 mm) in both transverse ence of columns of longitudinal fibers on both abaxial and ad- and longitudinal sections. axial sides of the veins extending to the epidermis, (3) absence Numerous endarch primary xylem initials surround the pith of a hypodermis of regimented cells, and (4) presence of a wedge (fig. 5F). These cells are ~10 mm in diameter and are flanked cen- of fibers at the leaf margin. The lamina of the glossopterid trifugally by long files of secondary xylem tracheids. Secondary ovuliferous organ Homevaleia gouldii also has a differentiated xylem tracheids are 15–25 mm in diameter with bi- to multiseriate mesophyll (Nishida et al. 2007), but cells on the sterile side, al- bordered pitting (fig. 5J). Ray cells are less well preserved than though large, do not form a prominent palisade layer equivalent longitudinal tracheids. Rays are uniseriate, 2–8 (typically around 5) to that of G. thirroulensis. cells high (fig. 5I), with 5–7 closely abutting bordered cupressoid The presence of fiber columns abaxial and adaxial to the pits generally in alternate arrangement (i.e., araucarioid cross- veins has not been noted in anatomically preserved Glossopteris field pitting; fig. 5H). leaves previously. However, Pant and Gupta (1971) noted the Seasonal growth increments are up to ~35 tracheids wide. occurrence of prominent fiber strands in macerated compressions Rings of the first few seasons tend to be broader, up to 700 mm, of Glossopteris leaves from Lopingian strata of India. The func- than subsequent growth rings, which are consistently around tional significance of the fiber bands in G. thirroulensis is uncer- 200 mm wide (fig. 5B,5G). Several specimens have strongly tain, although they likely afforded the leaf some additional asymmetrical growth rings (fig. 5D). Latewood is represented strength and perhaps even provided defense of the vascular sys- by the last 3–4 cells of each ring and has a relatively abrupt tran- tem against insect herbivores (particularly galling and fluid- sition from earlywood (fig. 5G). Small branch traces or epi- feeding specialists). Similarly, the thick wedge of fibers flanking cormic buds, 80–200 mm in diameter, are produced in loose the leaf margin may have provided extra rigidity to the lamina clusters at semiregular intervals along the axis (fig. 5L). A few margin and also made the leaf less palatable to margin-feeding axes show evidence of scarring and wound-recovery tissue foliavores. Galling, fluid feeding, and margin feeding were all (fig. 5M). Cells around the damaged areas are filled with opaque common arthropod herbivory strategies on other Permian glos- material and overgrown by distorted files of secondary wood. sopterids (Adami Rodrigues et al. 2004; Prevec et al. 2009, Remnants of the bark are preserved in a few cases. The bark is 2010; McLoughlin 2011; Slater et al. 2012, 2015; Cariglino differentiated broadly into three layers (fig. 5K). The innermost 2018). layer, ~300 mm thick, consists of compressed, thin-walled, Glossopteris thirroulensis represents the most abundantly spongy tissue enclosing canals reaching 75 mm in diameter. The preserved foliage in the silicified peat block. Volumetrically, middle layer, ~200 mm thick, consists of crushed thick-walled these leaves constitute a significant proportion (23.7%) of the cells, ~50 mm wide, with opaque contents. The outer layer, peat mass. They are commonly preserved in densely matted ac- ~150 mm thick, consists of crushed brick-like cells, ~60 mmwide, cumulations of apparently complete leaves that probably corre- which give this zone a lamellar appearance. spond to autumnal leaf falls. On this basis, the plant producing Remarks. Based on the absence of any obvious nonglossop- G. thirroulensis leaves was probably the dominant canopy plant terid foliage in the permineralized peat, we infer that these axes near the immediate site of peat accumulation. belong to glossopterid plants. The anatomical features of the secondary wood, particularly ray and pitting styles, are consis- Glossopterid Wood tent with the characters of Agathoxylon Hartig 1848. Many anatomically preserved fragments of secondary wood with similar Genus—Austroscleromedulloxylon Mussa, de Carvalho characters have also been attributed to Araucarioxylon Kraus et dos Santos 1980 ex Mussa 1986 in Schimper 1870 or Dadoxylon Endlicher 1847 (Philippe 1993; Rößler et al. 2014). Woods with secondary tissues vari- Species—Austroscleromedulloxylon sp. (Fig. 5A–5D, 5F–5M) ably assigned to Agathoxylon, Araucarioxylon,orDadoxylon have been reported widely in Permian strata across Gondwana Material. Slides AM F92048i-1, F92048k-2, F92048b-1, (Maheshwari 1972; Prasad 1982; Pant and Singh 1987; Bamford F92048b-3, F92048b-4, F92048b-9, F92048d-1, F92048d-3, 1999). The slender Thirroul Beach axes are anatomically similar F92048d-4, F92048d-5, F92048g-1, F92048g-2, F92048g-8, to larger woods attributed to Araucarioxylon (pAgathoxylon) and F92048j-1. arberi (Seward) by Beeston (1972) from the Lopingian of the Fig. 5 Austroscleromedulloxylon sp. (A–D, F–M) and Vertebraria australis McCoy emend Schopf 1982 (E). A, Transverse section of slender axis with prominent sclerotic nests in the pith; AMF92048b-4. B, Transverse section of slender axis with prominent sclerotic nests in the pith and well-defined growth bands in the secondary xylem; AMF92048j-1. C, Longitudinal section of slender axis with regular partitions of sclerenchyma in the pith; AMF92048g-1. D, Small axis with strongly asymmetrical growth; AMF92048j-1. E, Transverse section of root showing three secondary xylem wedges; AMF92048j-1. F, Details of pith margin, wedges of primary xylem, and initial ring of secondary xylem; AMF92048j-1. G, Regular seasonal growth rings in a young axis; AMF92048j-1. H, Radial longitudinal section showing cross-field with 5–7 simple pits; AMF92048b-9. I, Tangential longitudinal section showing short uniseriate rays; AMF92048b-1. J, Radial longitudinal section showing multiseriate bordered pitting on longitudinal tracheids; AMF92048i-1. K, Outer portion of a slender axis showing secondary xylem to the left flanked by bark differentiated into an innermost layer of compressed, thin-walled, spongy tissue enclosing canals, a middle layer of crushed thick-walled cells with opaque contents, and an outer layer of crushed brick-like cells producing a lamellar pattern; AMF92048b-3. L, Tangential longitudinal section showing multiple epicormics buds; AMF92048b-1. M, Outer zone of secondary xylem with zone of damage and reaction tissue; AMF92048d-3. Scale bars: A, B, D p 500 mm; C, G, L, M p 200 mm; E, H p 50 mm; F, I, K p 100 mm; J p 20 mm. 524 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Bowen Basin, but the latter lacks sclerotic nests in the pith (which arctica. The Antarctic woods clearly represent mature trees, with may be characteristic of distal twigs). Other possibly conspecific bark consisting of an inner layer of secondary phloem with dis- woods have been attributed to Dadoxylon (pAgathoxylon) continuous layers of fibers and successive outer layers of alter- arberi (Seward) by Sahni and Singh (1926) from Lopingian strata nating periderm and secondary phloem. The bark on the dimin- of the northern Sydney Basin, but those woods, similarly, lack utive Thirroul Beach axes appears to represent mostly primary sclerotic nests in the pith. Since the Thirroul Beach axes preserve cortical tissues or degraded secondary phloem, with only limited a few features of the primary tissues, they should not be assigned development of periderm represented by the regimented cells of to Agathoxylon, which is specifically employed to accommodate the middle and outer layers of the bark. The presence of canal- woods that retain only secondary tissues (Rößler et al. 2014). like voids in the inner layer of the bark suggests the possible Reviews of Gondwanan Permian woods by Maheshwari transport of resin or mucilage during the early stages of axis (1972), Prasad (1982), and Pant and Singh (1987) revealed very growth. few taxa with notable quantities of sclerotic cells in the pith. Woods retaining primary tissues that are most similar to the Glossopterid Roots examples from Thirroul Beach were originally illustrated by Mussa et al. (1980) from the Irati Formation (Kungurian) of Genus—Vertebraria Royle 1834 ex McCoy 1847 Brazil and later formally assigned to Austroscleromedulloxylon emend Schopf 1982 geraldinii and A. tabulatum (Mussa 1986). Few characters, apart from slightly more regimented sclerenchymatic septa in the pith Species—Vertebraria australis McCoy 1847 of A. tabulatum, separate the two Brazilian species and they emend Schopf 1982 (Fig. 5E) may be synonymous. The Thirroul Beach woods have regularly spaced but less continuous partitions in the pith, and these are Material. Sparse specimens on slides F92048i-1, F92048d-1, composed of more equidimensional sclereids than the Brazilian F92048j-1. forms, but they clearly fall within the circumscription of Aus- Description. Axes consisting of three or more radial troscleromedulloxylon. Similar slender woody axes with scleren- wedges of secondary xylem separated by cavities or degraded chymatous pith partitions have been reported but not illustrated cortical tissues (fig. 5E). Secondary xylem tracheids are roughly from upper Permian strata of the Bowen Basin (McLoughlin et al. square in cross-section and typically 10–20 mm in diameter. Pri- 2018), and until these eastern Australian wood assemblages are mary tissues in the center of the axis are generally degraded. studied in detail to discern their full range of variation, we retain Remarks. Glossopterid roots (Vertebraria australis)arevery the Thirroul Beach specimens under open nomenclature. scarce within the peat block. The specimens are poorly preserved Based on their diminutive size, common expression of asym- and strongly compacted. This contrasts with Guadalupian and metrical growth rings, and !1 mm wide growth increments, these Lopingian peat deposits of Antarctica, which are rich in roots axes probably represent small branches rather than the trunk (Schopf 1965, 1970; Neish et al. 1993). The Thirroul Beach spec- wood of seedlings. The sharp termination of secondary wood imens provide no additional anatomical details beyond those al- rings indicates growth in a strongly seasonal environment, but ready documented for permineralized Vertebraria roots from there are insufficient growth rings in any one axis to undertake Australia (Gould 1975; McLoughlin 1992), Antarctica (Schopf a meaningful quantitative appraisal of the growth series for de- 1965, 1982; Neish et al. 1993; Decombeix et al. 2009), and Brazil tailed paleoclimatic interpretations. (Mussa 1978). The regularity of sclerenchymatous wedges along the length of the pith suggests that these structures played some role in Glossopterid Megasporophylls (Fig. 6A–6E) strengthening the distal axes. The relative frequency of small axes in the deposit suggests that distal twigs were shed through Material. Several specimens sectioned in slides AM seasonal dehiscence or regularly detached by storms or other F92048i-1, F92048g-3, F92048j-1. environmental processes. Scar features are common in these axes Description. Laminar structures, gently arched or enrolled at (fig. 5M) and, in the absence of charring, may have been caused the margins (fig. 6A,6B); consisting of a 50–200 mm thick main by frost, insect, or physical damage (e.g., wind-induced abrasion lamina 1.5 mm (or greater) wide, tapering laterally into 0.2– against neighboring branches). The production of recovery 0.3 mm wide, 20–30 mm thick marginal wings. The main lamina tissues, together with the presence of epicormic buds (fig. 5L), consists of a relatively undifferentiated mesophyll with polygonal indicates that these glossopterid plants were able to effectively cells of 35–50 mm maximum dimensions (fig. 6D,6E). The lam- respond to adverse conditions in most cases. Epicormic buds ina has a prominent abaxial and adaxial epidermis of slightly have also been found in larger Permian glossopterid axes from inflated brick-shaped cells 15–20 mm in width and thickness Antarctica (Decombeix et al. 2010), and similar features have (fig. 6D,6E). Vascular bundles are cryptic, consisting of only a been described in Permian woods from Antarctica as leaf traces few tracheids !10 mm in diameter located centrally within the (Maheshwari 1972, pl. 10, fig. 3) and from Brazil as adventi- mesophyll. One specimen is markedly enrolled with the wings tious root traces (Mussa 1978, pl. 5, figs. 26–29), their presence curling inward in a revolute manner. The other specimens have affording the stems structural plasticity and enabling them to varying degrees of lamina arching. One specimen appears to bear respond more effectively to environmental stresses. an immature ovule on the inner surface of a deformed enrolled Bark is rarely preserved in glossopterid woods. Decombeix et al. lamina (fig. 6C). The ovule is somewhat distorted but appears (2016) illustrated the only previous record of bark in this group, to have been originally ovoid, ~800 mm long and 300 mm wide. the bark being up to 3 cm thick around large (17cmwide)seg- It was borne on a pedicel 70 mmlongand30mm wide. Other an- ments of glossopterid secondary wood from Skaar Ridge, Ant- atomical details of the ovule are ill-defined, but the walls appear MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 525

Fig. 6 Glossopterid megasporophylls. A, Revolute (or possibly involute) aborted(?) megasporophyll; AMF92048j-1. B, Arched megasporophyll with recurved wing; F92048i-1. C, Deformed megasporophyll bearing immature stalked ovule; F92048g-3. D, E, Charcoaliﬁed megasporophyll with prominent epidermis and roughly equidimensional mesophyll cells; F92048j-1. Scale bars: A, C–E p 100 mm; B p 500 mm.

to be thinner (~10–20 mm) than those of dispersed seeds occur- lacking elaborations except for slight thickening of the meso- ring elsewhere in the peat mass. testa. Vasculature restricted to seed base, undivided, and termi- Remarks. Although these structures are diminutive (only a nating at nucellar pad. few mm wide at most), they otherwise have similar architecture Etymology. From Illawarra—the coastal region south of and enrolled (revolute) vernation to permineralized glossopterid Sydney derived from the aboriginal Tharawal word allowrie fructifications from the Lopingian of the Bowen Basin, northeast- meaning “high place near the sea,” and -spermum (Greek: ern Australia, assigned to Homevaleia Nishida et al. 2007, and seeded). from coeval strata of Antarctica referred to Lonchiphyllum Ry- Type species. Illawarraspermum ovatum McLoughlin et berg et Taylor 2013. The small size of the Thirroul examples, Mays sp. nov. (here designated). and retention of an underdeveloped ovule on one specimen, Remarks. The new genus is established to accommodate suggests that they may represent immature or aborted mega- small, weakly flattened ovoid seeds with relatively thick walls sporophylls. The short pedicel at the base of the attached ovule that are otherwise unadorned. The new genus differs from other (fig. 6C) appears to be a character shared with several other anatomically preserved Gondwanan seeds by being signifi- scutiform glossopterid fructifications (e.g., Homevaleia Nishida cantly smaller (compare with Pachytestopsis, which encompasses et al. 2007; Lonchiphyllum Ryberg et Taylor 2013) but not all seeds with lengths 15 mm); lacking prominent wings (compare forms (e.g., Lakkosia Ryberg 2010); hence, it may have some sys- with Plectilospermum, Pachytestopsis,andLakkosia seeds); hav- tematic utility as more taxa are described. ing a thick, multilayered wall (compare with Lonchiphyllum); and lacking prominent elaborations of the exotesta or meso- fl Glossopterid Seeds testa around the micropyle or along the seed anks (compare with Choanostoma, Plectilospermum, and seeds of Homevaleia; Gould and Delevoryas 1977; Smoot and Taylor 1986a; Taylor — Genus Illawarraspermum McLoughlin et Mays gen. nov. and Taylor 1987; McLoughlin 1992; Klavins et al. 2001; Hold- gate et al. 2005; Nishida et al. 2007; Ryberg 2010; Ryberg and Diagnosis. Seeds platyspermic, small (!5 mm long), weakly Taylor 2013; McLoughlin et al. 2018). Although densely clus- flattened ovoid, with rounded to truncate base extending into a tered in the Thirroul Beach peat sample, Illawarraspermum seeds short broad pedicel, slightly tapered apex, and minimal wing have not been found attached to a megasporophyll. Nevertheless, development. Seed coat differentiated into three major layers: their size and preservation in the same layers as small partially en- a thin, spongy exotesta; a thick mostly sclerenchymatous meso- rolled laminar megasporophylls suggests that they are affiliated testa; and a very thin lamellar endotesta. Apex and micropyle with Dictyopteridiaceae fructifications. 526 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Species—Illawarraspermum ovatum McLoughlin et Mays thickened (to ~300 mm) at the micropyle (fig. 7K). Cells of the in- sp. nov. (Figs. 7A–7O, 8A–8H; Videos 1–5, Available Online) ner layer of the mesotesta are cubic to prismatic and tend to be aligned radially near the outer margin. Cells are moderately de- 2002 “Type B Ovules”; McManus et al., graded or masked in inorganic stains in most cases, but they P. 239, Pl. 3, Figures 1–3 reach 20 mm in diameter and 100 mmlong. Endotesta 50–110 mm thick, generally compressed and Holotype. Slide AM F92048d-5 (here designated; fig. 7B). stained or degraded, but locally consisting of a few layers of tab- Type locality, unit, and age. Thirroul Beach, southern Syd- ular cells ~10 mm thick and 25 mm long. The boundary between ney Basin, New South Wales, Australia (fig. 1); lower Wilton the endotesta and mesotesta is sharp, but the endotesta is com- Formation, Sydney Subgroup, Illawarra Coal Measures; monly detached from the mesotesta probably as a consequence Wuchiapingian. of postmortem cell contraction. Additional material. Numerous (190) whole and fragmen- The exotesta and mesotesta are slightly expanded at the tary seeds are preserved within the peat matrix; the best examples seed margin to form a rudimentary ridge up to 500 mm wide are represented in slides F92048k-2, F92048i-1, F92048k-1, (fig. 7I,7J). The marginal ridges appear to persist from the base F92048b-1, F92048b-4, F92048b-5, F92048b-6, F92048b-7, to the apex of the seed with more or less consistent width. F92048b-9, F92048b-10, F92048d-1, F92048d-2, F92048d-3, The micropyle consists of a simple funnel (up to 100 mm wide) F92048d-4, F92048d-5, F92048g-1, F92048g-2, F92048g-5, that narrows distally (fig. 7K). Apart from slight thickening of and F92048j-1. Sixty-six seeds (including whole or nearly intact the surrounding mesotesta, the micropyle has no elaborations. specimens) were identified embedded in hand sample AMF92048k The base of the seed is swollen by thickening of the mesotesta from the X-ray synchrotron data set; of these, three were visual- to form a 300 mm thick and 1–1.9 mm wide platform or short ized (F92048k internal specimens A–C; videos 1–5). pedicel with a truncate base (videos 2, 3). The vascular supply Etymology.FromLatin—ovatus, the inflected form of ovum consists of a single terete strand (40–110 mm wide and 430– (pegg), denoting the simple, egg-shaped form of the seeds. 750 mm long) that passes straight through the thickened chala- Diagnosis. Exotesta consisting of single-layered epidermis and zal platform and all layers of the integument to terminate at the multiple layers of spongy hypodermal cells; mesotesta compris- nucellar pad without branching (figs. 7L,8D; video 2); the in- ing an inner band of sclerenchyma and an outer band of thin- tegument is otherwise unvascularized. Preservation is insuffi- walled parenchyma; endotesta composed of thin, brick-shaped cient to yield details of the vascular cells. cells forming a lamellar pattern. Marginal ridge or wings rudi- The nucellus is represented by a basal discoid to concave pad mentary, consisting of !500 mm extensions of the exotesta and up to 110 mm thick (figs. 7H;8C,8G; videos 1, 3, 4) that at- mesotesta. Vasculature consisting of a single unbranched terete tenuates laterally into a nucellar membrane, which is generally strand passing straight through the chalaza and terminating in a contracted away from the seed coat to form a shriveled mass discoidal nucellar pad. Basal nucellar pad up to 110 mm thick within the center of the seed (figs. 7B–7F,8A,8B,8F; videos 3– tapering marginally into cutinized nucellar wall. Micropyle in 5). The nucellar pad is typically darkened, but cellular details the shape of a simple inverted cone. are not preserved. The nucellar membrane has a well-developed Description. Seeds 2.7–4.2 mm long, 1.5–4mmwideinthe dark cuticle, but cell outlines are not preserved (fig. 7O). Mega- primary plane (incorporating narrow wings), 1.2–2.1 mm thick gametophyte tissue is rarely preserved and typically consists of in the secondary plane; typically flattened ovoid with 1807 rota- degraded cellular debris. No archegonia or embryos were de- tional symmetry (figs. 7A–7G,7I,7J,8A,8B,8E). Seed integ- tected, and no pollen grains were preserved in the micropyle or ument consisting of a spongy exotesta, two-layered robust seed cavity. mesotesta, and thin endotesta. Remarks. All of the seed specimens are detached from other Exotesta generally preserved poorly, typically !100 mm plant organs and tend to be concentrated in bands within the si- thick, consisting of a single layer of epidermal cells underlain licified peat (fig. 8H). The seeds are of similar size and appear by several ill-defined layers of thin-walled spongy hypodermal to have been shed naturally at maturity. Although platyspermic cells (fig. 7N). Epidermal cells rectangular prismatic ~20 mm with 1807 rotational symmetry, a few seeds have a tilted short long and 15 mm thick. Epidermal cell walls slightly thickened axis, which is probably a consequence of postburial distortion and appearing dark where reasonably well preserved (fig. 7N). (video 5). Other postburial features include localized sulfide Hypodermal cells thin walled, roughly equidimensional, 15– mineralization, which is commonly associated with the endo- 30 mm in diameter, commonly degraded and compressed. testa, as shown by high X-ray attenuation in the CT profile Mesotesta typically 210–380 mm thick, consisting of two (fig. 8F). The lack of fine cellular preservation detracts from de- layers: an outer layer of thin-walled parenchyma cells and an in- tailed comparisons with other anatomically preserved Gond- ner layer of thick-walled sclereids (fig. 7M,7N). The boundary wanan Permian seeds. Illawarraspermum ovatum McLoughlin between the layers of the mesotesta is irregular and locally gra- et Mays sp. nov. appears identical in size and wall architecture dational, giving both layers variable thickness. The outer layer to type B ovules from the Lopingian of Antarctica illustrated by of the mesotesta is up to 375 mm thick but is commonly crushed McManus et al. (2002, pl. 3, figs. 1–3). The new species can be or completely degraded to leave a cavity. The ellipsoidal to po- readily distinguished from other previously described forms by lygonal cells of this layer are up to 60 mm in maximum dimen- its small size, rudimentary marginal wings/ridges, prominent sion. The inner layer of the mesotesta consists of cells with very basal platform, lack of exotesta elaborations, and the propor- thick walls, commonly with intense mineral staining (fig. 7K, tional thicknesses of the seed-wall layers (Gould and Dele- 7M). This zone is typically 160–220 mm thick, but expanded voryas 1977; Taylor and Taylor 1987; McLoughlin 1990c, to around 500 mm thick at the chalaza (fig. 7L), and only slightly 1992; Klavins et al. 2001; Holdgate et al. 2005; Nishida et al. Fig. 7 Seeds in thin section: Illawarraspermum ovatum McLoughlin et Mays sp. nov. A, Seed in longitudinal section showing basal pedicel and multiple generations of chalcedony infill; AMF92048j-1. B, Longitudinal section of seed; AMF92048d-5 (Holotype). C, Longitudinal section of seed; AMF92048j-1. D, Oblique section of seed showing basal nucellar pad; AMF92048i-1. E, Oblique section through seed; AMF92048d-2. F, Longitudinal section through seed showing contracted nucellar remnants; AMF920489g-2. G, Longitudinal section of a seed in the plane of narrowest dimension; AMF92048d-5. H, Enlargement of seed base showing vascular trace and nucellar pad. I, Transverse section of seed showing rudimentary lateral extensions; AMF92048i-1. J, Transverse section of seed showing minimal wing development; AMF92048g-2. K, Micro- pylar region of seed; AMF92048b-1. L, Enlarged base of seed showing squat pedicel and vascular trace; AMF92048j-1. M, Enlargement of seed wall showing robust cells of the inner mesotesta; AMF92048j-1. N, Enlargement of a portion of the seed wall showing thin rim of endotesta (bottom), covered by a darkened inner mesotesta interdigitating with spongy outer mesotesta, and enveloped by a multilayered exotesta; AMF92048d-2. O, Enlargement of nucellar membrane; AMF92048k-1. Scale bars: A p 500 mm; B–J, M p 200 mm; K, L, N p 100 mm; O p 50 mm. 528 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Fig. 8 X-ray synchrotron tomographic reconstructions of seeds: Illawarraspermum ovatum McLoughlin et Mays sp. nov. A–C, AMF92048k internal specimen A. A, Medial transverse section (M p mesotesta; N p nucellus; E p endotesta). B, Medial transverse section of rendered volume, basal view, colored volumes correspond to those labeled in A. C, Surface-rendered reconstruction, dorsal view, blue (semitransparent) p mesotesta; red (semitransparent) p endotesta; green (opaque) p nucellar membrane; yellow (opaque) p nucellar pad (video 1; videos 1–5 are available online). D, E, AMF92048k internal specimen B. D, Longitudinal section (V p vascular strand). E, Surface-rendered reconstruction, basal view, blue (semitransparent) p mesotesta; red (semitransparent) p endotesta; pink (opaque) p seed cavity; violet (opaque) p vascular strand (video 2). F, G, AMF92048k internal specimen C. F, Longitudinal section (S p probable authigenic sulﬁdes within the endotesta, represented in white by high X-ray attenuation). G, Surface-rendered reconstruction, oblique dorsal view, blue (semitransparent) p mesotesta; red (semitransparent) p endotesta; green (opaque) p nucellar membrane (with probable minor silica mineralization); yellow (opaque) p nucellar pad (videos 3–5). H, Representative tomographic section through the seed/charcoal-rich microfacies, including several specimens of I. ovatum variably inﬁlled with cryptocrystalline silica (arrowheads); AMF92048k. Scale bars: p A–G p 500 mm, H p 2000 mm.

2007; Ryberg 2010; Ryberg and Taylor 2013; Slater et al. 2015; wings. Several genera of fructiﬁcations attributed to this group McLoughlin et al. 2018). have been reported from the Sydney Basin previously, for exam- Illawarraspermum ovatum McLoughlin et Mays sp. nov. ple, Austroglossa, Dictyopteridium, Karingbalia, Plumstea- seeds were probably associated with dictyopteridioid glossop- dia, Scutum, and Senotheca (Rigby 1961; Holmes 1974, 1995; terid reproductive organs based on their size and diminutive White 1978; McLoughlin 1990b, 2012, 2016; Shi et al. 2010). MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 529

The short bulbous pedicels (on compressions) and indentations 40 mm wide and 60–70 mm long (fig. 9I,9J), referable to (on impressions) of various dictyopteridiacean fructifications Protohaploxipinus limpidus (Balme et Hennelly) Balme et (McLoughlin 1990a; Adendorff et al. 2002; Prevec et al. 2008; Playford 1967 or similar forms, and are inferred to derive from Prevec 2011, 2014; Ryberg et al. 2012) match the size of the glossopterid gymnosperms (Lindström et al. 1997). Other pol- platform at the base of the I. ovatum seeds and probably repre- len grains include large (up to 120 mm long) sulcate or poly- sent detachment scars. The central pits/knobs on those indenta- plicate forms (fig. 9K) that are referable to Cycadopites or tions/pedicels probably correspond to the vascular supply to the Praecolpatites (Foster 1979) and are potentially affiliated with seed. various seed ferns, cycads, or Ginkgoales (Balme 1995). Pterido- phyte spores occur rarely within small leptosporangia (fig. 9H) Glossopterid Pollen Sacs but are generally dispersed sparsely within the peat matrix. Some are small (20–40 mm diameter), granulate to weakly spi- Genus—Arberiella Pant et Nautiyal 1960 nose, triangular to circular, trilete spores (fig. 9L) that are similar to forms assigned to Apiculatisporis or Horriditriletes from Species—Arberiella africana Pant et the Lopingian of eastern Australia (Foster 1979). Some granu- Nautiyal, 1960 (Fig. 9A–9G) late circular spores are darkened and not identifiable to genus (fig. 9M). Other triangular trilete spores, 50–65 mm in diameter, Material. Clustered or isolated pollen sacs and sporangia oc- with cristate, rugulate, or reticulate sculpture (fig. 9N,9O), are cur in most slides. The best examples are available in slides AM similar to forms assigned to Camptotriletes warchianus Balme F92048i-1, F92048k-2, F92048b-1, F92048b-3, F92048b-6, 1970 or to Dictyotriletes spp. (Foster 1979), taxa of uncertain F92048b-10, F92048d-1, F92048d-2, F92048d-3, F92048g-2, pteridophytic affinities. The dispersed spore and pollen taxa F92048g-7, F92048j-1, and F92048k-1. recorded in the peat are relatively common forms in Lopingian Description. Pollen sacs, 0.8–1.2 mm in maximum di- strata of Australia and India (Balme 1970; Helby 1970; Foster mensions, are common throughout the peat matrix. They occur 1979) and are consistent with a Wuchiapingian age inferred for isolated or in densely packed clusters of up to 20 sacs and are the Wilton Formation based on its stratigraphic position. generally ellipsoidal, except where compressed and distorted by surrounding material (fig. 9A,9B). All appear to have a wall Charcoal (Fig. 10A–10H) consisting of a single layer of bulbous cells, commonly filled by opaque matter (fig. 9E–9G). These cells average 12 mm tall, Material. All slides in the collection contain at least some 16 mm wide, and, based on oblique sections, appear to be elon- charcoalified particles. The best examples occur in slides AM gate and parallel (fig. 9E), forming a striate surface. Abundant F92048i-1, F92048k-2, F92048b-1, F92048d-4, F92048d-5, pollen grains are retained in many of these sacs, but their pres- F92048g-1, F92048g-2, F92048j-1, and F92048k-1. ervational quality is poor (fig. 9C–9G). All appear to be bi- Description. Charcoal is common within the peat matrix and saccate pollen with hollow wings and ill-defined taeniae on is represented mainly by secondary wood fragments (fig. 10A– the corpus. In situ pollen are typically ~20 mm long, 30–45 mm 10G) but also includes portions of leaf and bark (fig. 10H). In- wide, and variably haploxylonoid to diploxylonoid. dividual charcoal clasts are up to 14 mm in maximum dimen- Remarks. We did not detect any connections between pol- sion. Most fragments are elliptical to oblong. Charcoal occurs len sacs or attachments to a subtending organ, but the dense either clustered in discrete bands or dispersed as isolated par- clusters of sacs are otherwise similar to the arrangement in ticles within leaf, detritus, or seed-rich microfacies. The majority Ediea homevalensis (Nishida et al. 2014). Individual sacs are of charcoal particles show some degree of rounding (fig. 10A, consistent in dimensions, wall structure, and contents with 10D). Some particles retain angular features or a mix of angular compressed glossopterid microsporangia assigned to Arberiella and abraded textures (fig. 10B,10C,10E). All charcoal particles africana by Pant and Nautiyal (1960) and with permineralized are less compressed than other plants in the deposit. In many pollen-bearing organs referred to Arberiella sp. cf. A. africana cases, silica-filled fractures penetrate and radiate from charcoal by Lindström et al. (1997). particles (fig. 10A,10E). A few charcoalified clusters of tracheids with thin scalariform thickenings may derive from pteri- Incertae Sedis dophytes (fig. 2F,2G), but most charcoal consists of secondary gymnosperm wood. All available fragments of charcoalified sec- Dispersed Pollen and Spores ondary wood have ray characters and bi- to multiseriate pitting on the radial walls of longitudinal tracheids (fig. 10F,10G) that Material. All slides contain dispersed pollen and spores of are identical to the anatomy of noncharcoalified Austroscle- generally poor preservational quality. Illustrated examples oc- romedulloxylon wood described above. In the absence of pri- cur in slides AM F92048k-2, F92048b-5, F92048b-6, and mary tissues, such fragments would normally be assigned to F92048b-10. Agathoxylon. Description and remarks. Various isolated pollen and Remarks. Fire appears to have been a common feature of spores occur within the peat matrix. In most cases, extensive all Gondwanan glossopterid-dominated mire ecosystems. Char- corrosion of the exine, strong compression, or masking by coal is found abundantly in silicified peats from Australia and opaque materials precludes confident identification of these Antarctica (Slater et al. 2015), and fusinite (charred woody ma- grains. In a few cases, grains retain sufficient structural or sculp- terial) is a major constituent of Gondwanan Permian coals and tural details to assign them to broad biological categories. Most carbonaceous shales (Diessel and Smyth 1995; Shi and Mc- identifiable dispersed grains are taeniate bisaccate pollen, ~20– Loughlin 1997; Shivanna et al. 2017; Jasper et al. 2013). The Fig. 9 Pollen sacs (Arberiella africana Pant et Nautiyal 1960), sporangia, and dispersed pollen and spores. A, Cluster of A. africana pollen sacs; AMF92048b-6. B, Cluster of A. africana pollen sacs with a single layer of darkened wall cells; AMF92048b-6. C, Enlargement of pollen sac contents revealing in situ bisaccate pollen; AMF92048d-3. D, Single A. africana pollen sac containing bisaccate pollen; AMF92048b-6. E, Oblique section of A. africana sac showing blackened elongate wall cells; AMF92048i-1. F, Elongate A. africana pollen sac; AMF92048b-1. G, Small A. africana pollen sac in transverse section showing single layer of inflated and darkened wall cells; AMF92048b-10. H, Fern sporangium containing darkened spinose spores; AMF92048b-6. I, Sections through bisaccate pollen grains; AMF92048b-5. J, Protohaploxipinus limpidus taeniate bisaccate pollen grain; AMF92048b-6. K, Cycadopites(?) sp. monosulcate pollen grain; AMF92048b-10. L, Cluster of trilete spores (Horriditriletes sp.); AMF92048b-10. M, Darkened granulate spore; AMF92048b-6. N, Camptotriletes warchianus Balme 1970; AMF92048b-10. O, Camptotriletes sp.; AMF92048k-2. Scale bars: A, E p 100 mm; B p 200 mm; C, I, J, L–O p 20 mm; D, F–H, K p 50 mm.

530 Fig. 10 Charcoalified tissues in permineralized peat. A, Large rounded woody clast with radiating, silica-filled fractures; AMF92048j-1. B, Slender, angular wood fragment; AMF92048j-1. C, Angular wood fragment in radial section showing characters consistent with Austro- scleromedulloxylon sp.; AMF92048j-1. D, Rounded clast of secondary wood; AMF92048j-1. E, Angular clast of secondary wood contributing to deformation of surrounding leaf remains and partly flanked by a silica-filled void; AMF92048d-4. F, Enlargement of tracheids in secondary wood showing bi- to multiseriate pitting; AMF92048j-1. G, Multiseriate pitting and fine fracturing of tracheid walls in secondary wood; AMF92048k-1. H, Brick-like cells of possible bark tissue; AMF92048k-1. Scale bars: A, D, H p 200 mm; B, C, E p 100 mm; F p 20 mm; G p 50 mm.

531 532 INTERNATIONAL JOURNAL OF PLANT SCIENCES

mix of rounded and angular charcoal fragments in the Thirroul are known in the mesophyll of Noeggerathiopsis (cordaitalean) Beach peat suggests derivation of the material from both the leaves from Antarctica (McLoughlin and Drinnan 1996). More- local community and from more distant sources via aqueous over, dark amorphous substances in hypodermal cells that might transport. include resin have been reported from Antarctic permineralized Glossopteris leaves (Pigg 1990). Resin (Fig. 11G–11I) Kingdom—Fungi Material. Slides AM F92048k-2, F92048d-1, and F92048k-1. Description. Opaque spherical to ellipsoidal bodies ~50– Pockets and Filaments (Fig. 11A) 200 mm in diameter, with relatively smooth margins, occur scattered sparsely throughout the peat matrix (fig. 11G–11I). Material. Slide AM F92048k-2. They are not concentrated in any particular microfacies. They Description. Some spindle-shaped cavities in the normal and show no internal differentiation of contents, but some have a charcoalified wood contain opaque filaments that locally branch slightly granular appearance. and amalgamate (fig. 11A). The filaments are !2 mm thick and Remarks. These structures probably represent droplets of reach 120 mm long, traversing the width of the cavities. solidified resin shed from a seed plant. The surfaces of these Remarks. Few details are discernible on these filaments bodies are generally too smooth and their contents too uniform owing to their opaque nature. However, their presence within to represent invertebrate coprolites. Resinite is generally a mi- spindle-shaped cavities in wood is similar to occurrences of nor constituent of Gondwanan Permian coals (Diessel and white pocket-rot fungi reported from Guadalupian–Lopingian Smyth 1995), but opaque ellipsoidal resin bodies of similar size strata of the Transantarctic Mountains (Stubblefield and Tay-

Fig. 11 Fungi and resin in permineralized peat. A, Spindle-shaped cavities in charcoalified wood traversed by filamentous fungal hyphae; AMF92048k-2. B–F, Fungal sclerotia with variably preserved central filaments and a dense outer rind; respectively, AMF92048g-3, AMF92048d- 1, AMF92048d-1, AMF92048g-1, AMF92048g-1. G–I, Variably sized and textured spherical-ellipsoidal opaque resin blebs; respectively, AMF92048k-2, AMF92048d-1, AMF92048k-1. Scale bars: A p 10 mm; B; E, G, H p 50 mm; C, D, F, I p 100 mm. MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 533 lor 1986; Harper et al. 2017) and Prince Charles Mountains a mixed assemblage that is not clearly dominated by any one or- (Weaver et al. 1997; Slater et al. 2015) of Antarctica and from ganic component (fig. 13D). the Bowen Basin of eastern Australia (McLoughlin 1992). Collectively, the peat consists of 125% glossopterid leaves by volume, ~22% axial remains (roots, bark, secondary xylem, Sclerotia (Fig. 11B–11F) pith, and charcoalified woody fragments), ~8.1% glossopterid seeds, ~10% pteridophyte fragments, 30% fine plant detritus, Material. Slides AM F92048b-6, F92048d-1, F92048d-1, and the remaining ~10% is represented by isolated reproductive F92048g-1, and F92048g-3. structures, resin blebs, and silica-filled void space (fig. 13E). Description. Roughly spherical bodies typically consist- Clastic mineral grains are not evident within the peat. All void ing of an outer dense rind and an inner spongy, filamentous, space has been filled with cryptocrystalline silica and authigenic or degraded zone are scattered throughout the peat matrix sulfides. The abundance of glossopterid remains in the peat is (fig. 11B–11F). The outer rind is generally stained pale brown, consistent with the composition of Lopingian adpression floras is ~10–30 mm thick, and consists of densely packed filamentous from eastern Australia (McLoughlin 1994a, 1994b; Holmes material (fig. 11B,11D,11E). The inner zone consists of less 1995), indicating that this plant group dominated both peat- dense filamentous matter that is commonly more degraded and forming mires and floodplain areas of clastic sedimentation incorporates scattered opaque material that is possibly inorganic within Australian Lopingian alluvial systems. (fig. 11C,11F). Remarks. These bodies represent a consistently small Discussion (!1%) proportion of the peat volume and do not occur in any consistent relationship to other fossil organs or organic micro- Taphonomy and Paleoenvironment facies. They bear some similarities to sclerotia of extant fungi. Sclerotia are small, commonly spherical asexual reproductive Preservational quality varies within the peat among the as- structures that consist of tightly packed hyphal filaments and sorted plant organs and tissues. Consistent with other Gond- are produced by a wide range of fungal clades (Smith et al. wanan Permian peats, thin-walled cells of pith, phloem, cam- 2015). The fossils in the Thirroul peat sample also bear similar- bium, and cortex, for example, tend to be very poorly preserved ities in size and architecture to inertinitic (oxidized) elliptical or or entirely degraded. Cells with more robust walls thickened spherical bodies found in Australian Permian coals that are typ- by lignin, suberin, or sporopollenin tend to be best preserved ically assigned to the maceral sclerotinite or funginite (Diessel (e.g., xylem, seed mesotesta, and sclerenchyma tissues, and and Smyth 1995; Lyons 2000). palynomorphs). Intermediate grades of preservation are evident among leaf mesophyll and epidermal cells. The same pattern is Volumetric Composition of the Peat evident among these tissues with respect to resistance to compaction. In general, seeds and wood (both charcoalified and Although representing only a small sample, the perminer- noncharcoalified) show relatively low degrees of compression, alized peat block incorporates several recognizable microfacies whereas gymnosperm leaves, sporangia, and megasporophylls, of 5–20 mm thickness, each with gradational boundaries. The together with pteridophyte remains, tend to be moderately to microfacies are variably dominated by (1) matted leaves with strongly compressed. only sparse seeds and wood fragments (fig. 12B,12D); (2) cha- The peat itself shows some structural heterogeneities. Dis- otically oriented seed and charcoal accumulations with rela- tinct microfacies (on the scale of 5–20 mm) are developed, al- tively sparse and contorted leaves (fig. 12A,12C,12E); and though they have gradational boundaries. We interpret the (3) zones of finely degraded leaf and sporangial debris locally three major organic microfacies to represent (1) autumnal leaf with dispersed spores, pollen, and fungal sclerotia (fig. 12F). fall deposits (fig. 12B,12D), (2) seed- and wood/charcoal-rich Leaf-rich microfacies are dominated (150% volume) by mat- accumulations through aqueous reworking of plant debris in ted occurrences of Glossopteris homevalensis and G. thirrou- the mire, particularly after fire events (fig. 12A,12C,12E), and lensis (figs. 12B,12D,13A). Putative pteridophyte leaves and (3) detrital zones developed during intervals of little organic in- fine detritus are also significant components of this microfacies put to the peat surface or microbial degradation of particular (with volumes 19%). laminae (fig. 12F). The lack of transported mineral particles in Seed- and charcoal-rich microfacies contain around 25% the peat indicates organic accumulation at a site isolated from glossopterid and pteridophyte leaves. Seeds (8.5%) and char- clastic input. coal (12.1%) are common (figs. 12C,13B), occurring as irreg- Despite the lack of siliciclastic particle input, the mild ularly arranged and locally abraded particles, giving this micro- and near-uniform X-ray attenuation response from sample facies a blocky texture (fig. 12E). Approximately 66 complete AMF92048k indicates a very high silicate content for this peat or broken specimens of Illawarraspermum ovatum were identi- deposit. This is indicative of near-homogeneous silicification, fied by X-ray tomography within a hand sample of ~7990 mm3 resulting in low attenuation contrast in the tomographic recon- volume (~8.3 specimens/cm3). Silica-filled voids and plant de- struction. Furthermore, the small fossils preserved within a rel- tritus are also common in this microfacies (figs. 8H,12C). atively large volume of silica, which significantly attenuated the Detritus-rich microfacies consist of around 45.3% finely com- incoming X-rays, would have constrained the resolution further minuted plant debris (figs. 12F,13C), and some seeds host lo- (Sutton et al. 2014). However, the regions of relatively high or- calized pyrite mineralization (fig. 8H). Leaves (28.5%) and seed ganic carbon are easily discernible in the X-ray tomographic re- fragments (8.9%) make up the next most important compo- construction, especially the dense seed testae or chemically inert nents of this microfacies. Other parts of the peat block contain charcoal. These results were only achieved by employing phase- 534 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Fig. 12 Peat microfacies. A, Seed- and wood-rich microfacies; AMF92048j-1. B, Laminated leaf-rich microfacies; AMF92048i-1. C, Seed- and wood-(charcoal)-rich microfacies; AMF92048k-1. D, Enlargement of leaf-rich microfacies showing matted Glossopteris leaves (pautumnal leaf accumulations); AMF92048b-11. E, Seed- and wood-(charcoal)-rich microfacies; AMF92048k-2. F, Detritus-rich microfacies; AMF92048k-2. Scale bars: A–C, E p 2mm;D p 100 mm; F p 20 mm. contrast CT, which enables the differentiation of surfaces, even 10E), which were resistant to compaction and whose open between materials of similar X-ray attenuation properties (e.g., cells potentially provided effective conduits for mineral-bearing Dunlop et al. 2012). groundwaters. In hot spring environments, plant surfaces may The time frame for permineralization of the peat is difficult become encrusted by silica over a time frame of days to weeks to resolve. Silicification occurred after degradation of most thin- (Channing and Edwards 2013), becoming fully permineralized walled tissues but before there was significant compaction of after a few years (Butts 2014). We find no evidence of hot spring woody tissues and seeds. Multiple phases of silicification were paleoenvironments in the southern Sydney Basin, but felsic to apparently involved in the permineralization process, as evi- intermediate volcanic ash beds are common (Carr et al. 2003). denced by numerous concentric infillings of seed chambers Decomposition of glasses in these tuffs is probably the chief (fig. 7A–7C,7I), the absence of any remaining pore spaces, and source of silica for wood and peat permineralization in the Syd- the presence of sporadic silica-filled fractures that transect pre- ney Basin (Diessel 1985). Permineralization after burial within viously permineralized organic matter (figs. 5C,10E). Many of clastic sediments is probably a slower process. Moreover, per- these fractures are focused around charcoal particles (fig. 10A, mineralization proceeds from initial coating of organic mat- MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 535

Fig. 13 Pie charts of peat component abundance. A, Percentages of components in leaf-rich microfacies. B, Percentages of components in seed/charcoal-rich microfacies. C, Percentages of components in plant detritus-rich microfacies. D, Percentages of components in mixed microfacies. E, Gross percentages of components in the entire peat. ter by amorphous opal-A through progressive conversions to ing the uppermost markers of cold sea-floor conditions in the opal-C, opal-CT, and ultimately to chalcedony and quartz over southern Sydney Basin occur in the Erins Vale Formation and timescales of tens of thousands of years (Scurfield and Segnit upper Wilton Formation (Bamberry 1991). These represent 1984; Channing and Edwards 2013; Mustoe 2017). Given the the terminal expression of the ultimate (P4) glacial interval of moderate degree of degradation and compaction evident in the Late Paleozoic Ice Age in eastern Australia (Fielding et al. some components of the peat, we consider that initial silicifica- 2008) and attest to cool to cold (seasonally freezing) conditions tion probably occurred over a timescale of years to decades, for the early Wuchiapingian in the Sydney Basin, then located with subsequent conversion of opaline silica to chalcedony over at ~757S (Waschbusch et al. 2009). millennia. The peat-forming community appears to have been domi- Marked seasonality in the environment is evidenced through nated by glossopterid gymnosperms. No other gymnosperms the occurrence of both autumnal leaf accumulations and prom- were detected in the peat, but the paleovegetation had an un- inent growth rings in glossopterid axes. Dropstones represent- derstory of ferns and lycophytes. Fungal remains are present but 536 INTERNATIONAL JOURNAL OF PLANT SCIENCES not well preserved, so it is difficult to confidently assess their im- Significance and Conclusions portance to the local community. We did not detect any un- equivocal examples of coprolites or arthropod remains in the This study has revealed a new late Permian (Wuchiapingian) peat, so the significance of herbivores and detritivores in the permineralized peat occurrence dominated by glossopterid paleocommunity is uncertain. Lenses of abundant macrochar- leaves, seeds, and charcoalified and noncharcoalified wood frag- coal indicate that fire was common in the local environment ments at Thirroul Beach in the southern Sydney Basin in Aus- and is consistent with relatively high atmospheric oxygen con- tralia. Anatomical investigations have identified a new species centrations postulated for the Lopingian (Glasspool and Scott of Glossopteris leaf and another new genus and species of seed, 2010; Belcher et al. 2013). which was analyzed using a combination of light microscopy and synchrotron X-ray CT. Other anatomically preserved leaf Comparison with Other Permian species in the deposit are conspecific with forms of equivalent Gondwanan Permineralized Peats age from Antarctica and eastern Australia. The new occurrence highlights the potential of foreland basins with a high volcanic The organic content of the Thirroul Beach peat block is ash input as prospective regions for additional discoveries of an- broadly consistent with that of other Permian peat and coal atomically preserved plant assemblages. Apart from providing deposits in eastern Gondwana in being dominated by the re- anatomical information on the entombed plants, such deposits mains of glossopterid gymnosperms (Gould and Delevoryas provide an understanding of the taxonomic and structural con- 1977; Taylor et al. 1989; McLoughlin 1992; Balme et al. 1995; stituents of peats that were converted into the vast Permian coal Pigg and McLoughlin 1997; McManus et al. 2002; Slater et al. deposits of Gondwana. Moreover, anatomical studies reveal 2015). Although few quantitative studies of these permineral- the architecture of the peat profile, in this case identifying dis- ized assemblages have been undertaken, the Thirroul peat dif- tinct gradational microfacies dominated respectively by leaves, fers from the three main Antarctic peat deposits (Skaar Ridge seeds and charcoal, and finely macerated plant detritus. Ana- and Collinson Ridge in the Transantarctic Mountains and the tomical preservation of the plants also provides some paleo- Radok Lake locality in the Prince Charles Mountains) in having climatic signals in the form of seasonal leaf fall and growth rings a markedly lesser representation of glossopterid roots (Verte- with abrupt termination of latewood that are consistent with the braria). For example, Vertebraria constitutes ~33% of the vol- high-paleolatitude setting of the Sydney Basin in the Lopingian ume of the Radok Lake peat, although that value reduces to during the terminal phase of the Late Paleozoic Ice Age. ~5% in charcoal-rich microfacies (Slater et al. 2015). Of the Australian permineralized peats, the example from the Wuchia- pingian Burngrove Formation in the central Bowen Basin is also Acknowledgments rich in Vertebraria (McLoughlin 1992). The Thirroul Beach peat has markedly greater similarities to the Changhsinghian Financial support to S. McLoughlin from the Swedish Re- peats recorded from Katoomba in the central Sydney Basin and search Council (VR grants 2014-5234 and 2018-04527) and from Homevale in the northern Bowen Basin in containing few National Science Foundation (project no. 1636625) is gratefully roots but being rich in leaves and dispersed seeds. acknowledged. C. Mays acknowledges technical support from The Thirroul peat appears to represent a predominantly leaf- staff at the Australian Synchrotron and financial support from litter assemblage with interspersed bands of locally winnowed the Australian Nuclear Science and Technology Organisation charcoal and seeds. The Antarctic assemblages and that from (Australian Synchrotron grant 11959). We thank two anony- the Burngrove Formation in the Bowen Basin appear to repre- mous reviewers for their constructive comments. This paper is sent essentially root mats with locally interspersed lenses of leaf dedicated to Gar Rothwell in honor of his long career studying and subaerial axis debris. permineralized plant fossils throughout the geological record.

Literature Cited

Adami-Rodrigues K, R Iannuzzi, ID Pinto 2004 Permian plant-insect ——— 1995 Fossil in situ spores and pollen grains: an annotated interactions from a Gondwana ﬂora of southern Brazil. Fossils Strata catalogue. Rev Palaeobot Palynol 87:81–323. 51:106–125. Balme BE, AP Kershaw, JA Webb 1995 Floras of Australian coal Adendorff R, S McLoughlin, MK Bamford 2002 A new genus of measures, with notes on their associated Mesozoic faunas. Pages 41– ovuliferous glossopterid fruits from South Africa. Palaeontol Afr 62 in CR Ward, HJ Harrington, CW Mallett, JW Beeston, eds. Geol- 38:1–17. ogy of Australian coal basins. Geological Society of Australia Coal Agnew D, M Bocking, K Brown, M Ives, D Johnson, M Howes, B Geology Group Special Publication 1, Sydney. Preston, R Rigby, P Warbrooke, CR Weber 1995 Sydney Basin- Balme BE, JPF Hennelly 1956 Trilete sporomorphs from Australian Newcastle Coalﬁeld. Pages 197–212 in CR Ward, HJ Harrington, Permian sediments. Aust J Bot 4:240–260. CW Mallett, JW Beeston, eds. Geology of Australian coal basins. Balme BE, G Playford 1967 Late Permian plant microfossils from the Geological Society of Australia Coal Geology Group, Special Pub- Prince Charles Mountains, Antarctica. Rev Micropaleontol 10:179–192. lication 1, Sydney. Bamberry WJ 1991 Stratigraphy and sedimentology of the Late Perm- Balme BE 1970 Palynology of Permian and Triassic strata in the Salt ian Illawarra Coal Measures, southern Sydney Basin, New South Range and Surghar Range, West Pakistan. Pages 305–454 in B Kum- Wales. PhD thesis, University of Wollongong. mel, C Teichert, eds. Stratigraphic boundary problems: Permian and Bamford MK 1999 Permo-Triassic fossil woods from the South Af- Triassic of West Pakistan. University of Kansas, Special Publication 4. rican Karoo Basin. Palaeontol Afr 35:25–40. MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 537

Beeston JW 1972 A specimen of Araucarioxylon arberi (Seward) Glasspool IJ 2000 Megaspores from the Late Permian, Lower Whybrow Beeston comb. nov. from Queensland. Geol Surv Queensl Publ 352, coal seam, Sydney Basin, Australia. Rev Palaeobot Palynol 110:209– Palaeontol Pap 27:17–20. 227. Belcher CM, ME Collinson, AC Scott 2013 A 450-million-year his- ——— 2003 A review of Permian Gondwana megaspores, with par- tory of fire. Pages 229–249 in CM Belcher, ed. Fire phenomena ticular emphasis on material collected from coals of the Witbank Ba- and the earth system. Wiley, Chichester. sin of South Africa and the Sydney Basin of Australia. Rev Palaeobot Bharadwaj DJ, RS Tiwari 1970 Lower Gondwana megaspores: a Palynol 124:227–296. monograph. Palaeontographica 129B:1–70. Glasspool IJ, AC Scott 2010 Phanerozoic atmospheric oxygen con- Brongniart A 1828 Prodrome d’une histoire des végétaux fossiles. centrations reconstructed from sedimentary charcoal. Nat Geosci F. G. Levrault, Paris. 3:627–630. ——— 1831 Histoire des végétaux fossiles. 1 (5–6). Pages 209–264 Good CW, TN Taylor 1970 On the structure of Cordaites felicis in G. Dufour et E. d’Ocagne, Paris. Benson from the Lower Pennsylvanian of North America. Palae- Butts SH 2014 Silicification. Pages 15–33 in MLaflamme, JD Schiff- ontology 13:29–39. bauer, SAF Darroch, eds. Reading and writing of the fossil record: Gould RE 1970 Palaeosmunda, a new genus of siphonostelic osmun- preservational pathways to exceptional fossilization. The Paleontolog- daceous trunks from the Upper Permian of Queensland. Palaeon- ical Society Papers, vol 20. Yale University Press, New Haven, CT. tology 13:10–28. Cariglino B 2018 Patterns of insect-mediated damage in a Permian ——— 1975 A preliminary report on petrified axes of Vertebraria Glossopteris flora from Patagonia (Argentina). Palaeogeogr Palaeo- from the Permian of eastern Australia. Pages 109–115 in KSW climatol Palaeoecol 507:39–51. Campbell, ed. Gondwana geology. Australian National University Carr PF, M Fanning, BG Jones, AC Hutton 2003 Geochronology of Press, Canberra. coal measures in the Sydney Basin from U-Pb shrimp dating of airfall Gould RE, T Delevoryas 1977 The biology of Glossopteris: evidence tuffs. Pages 303–305 in AC Hutton, BG Jones, PF Carr, B Acker- from petrified seed-bearing and pollen-bearing organs. Alcheringa mann, AD Switzer, eds. 35th Sydney Basin Symposium on Advances 1:387–399. in the Study of the Sydney Basin. School of Geosciences, University of Harper CJ, A-L Decombeix, EL Taylor, TN Taylor, M Krings 2017 Wollongong, Australia. Fungal decay in Permian glossopteridalean stem and root wood Channing A, D Edwards 2013 Wetland megabias: ecological and eco- from Antarctica. IAWA J 38:29–48. physiological filtering dominates the fossil record of hot spring floras. Harper CJ, TN Taylor, M Krings, EL Taylor 2013 Mycorrhizal Palaeontology 56:523–556. symbiosis in the Paleozoic seed fern Glossopteris from Antarctica. Decombeix A-L, EL Taylor, TN Taylor 2009 Secondary growth in Rev Palaeobot Palynol 192:22–31. Vertebraria roots from the Late Permian of Antarctica: a change in Hartig T 1848 Beiträge zur Geschichte der Pflanzen und zur Kenntnis developmental timing. Int J Plant Sci 170:644–656. der norddeutschen Braunkohlen-Flora. Bot Zeitung 6:122–128, 137– ——— 2010 Epicormic shoots in a Permian gymnosperm from Ant- 141, 166–172, 185–190. arctica. Int J Plant Sci 171:772–782. Hass H, NP Rowe 1999 Thin sections and wafering. Pages 76–81 in ——— 2016 Bark anatomy of late Permian glossopterid trees from TP Jones, NP Rowe, eds. Fossil plants and spores: modern tech- Antarctica. IAWA J 37:444–458. niques. Geological Society of London, Bath. Diessel CFK 1985 Tuffs and tonsteins in the coal measures of New South Helby RJ 1970 A biostratigraphy of the Late Permian and Triassic Wales, Australia. Pages 197–210 in Proceedings of the 10th Interna- of the Sydney Basin, PhD thesis, University of Sydney, Australia. tional Congress on Carboniferous Stratigraphy and Geology, Madrid. ——— 1973 Review of Late Permian and Triassic palynology of New Diessel CFK, M Smyth 1995 Petrographic constituents of Australian South Wales. Geol Soc Aust Spec Publ 4:141–155. coals. Pages 63–81 in CR Ward, HJ Harrington, CW Mallett, JW Holdgate GR, S McLoughlin, AN Drinnan, RB Finkelman, JC Willett, Beeston, eds. Geology of Australian coal basins. Geological Society LA Chiehowsky 2005 Inorganic chemistry, petrography and palaeo- of Australia Coal Geology Group Special Publication 1, Sydney. botany of Permian coals in the Prince Charles Mountains, East Dunlop JA, S Wirth, D Penney, A McNeil, RS Bradley, PJ Withers, Antarctica. Int J Coal Geol 63:156–177. RF Preziosi 2012 A minute fossil phoretic mite recovered by phase- Holmes WBK 1974 On some fructifications of the Glossopteridales contrast X-ray computed tomography. Biol Lett 8:457–460. from the Upper Permian of New South Wales. Proc Linn Soc N S W Endlicher S 1847 Synopsis coniferarum. Scheitlin & Zollikofer, 98:131–141. St. Gallen, Switzerland. doi:10.5962/bhl.title.15336. ——— 1995 The Late Permian megafossil flora from Cooyal, Etheridge R Jr 1894 On the mode of attachment of the leaves or fronds New South Wales, Australia. Pages 123–152 in DD Pant, ed. Global to the caudex in Glossopteris. Proc Linn Soc N S W 19:228–258. environment and diversification of plants through geological time. ——— 1899 On a fern (Blechnoxylon talbragarense), with second- Birbal Sahni centenary volume. South Asian Publishers, Allahabad, ary wood, forming a new genus, from the coal measures of the India. Talbragar district, New South Wales. Rec Aust Mus 3:135–147. Huyskens MH 2014 Improving precision and accuracy of U-Pb geo- Fielding CR, TD Frank, LP Birgenheier, MC Rygel, AT Jones, J chronology with application to the Permian period. PhD disserta- Roberts 2008 Stratigraphic imprint of the Late Paleozoic Ice Age tion, Australian National University, Canberra. in eastern Australia: a record of alternating glacial and nonglacial Jasper A, M Guerra-Sommer, AMD Abu Hamad, M Bamford, MEC climate regime. J Geol Soc 165:129–140. Bernardes-de-Oliveira, R Tewari, D Uhl 2013 The burning of Gond- Fielding CR, R Sliwa, RJ Holcombe, J Kassan 2000 A new palaeo- wana: Permian fires on the southern continent: a palaeobotanical ap- geographic synthesis of the Bowen Basin of central Queensland. proach. Gondwana Res 24:148–160. Pages 287–302 In JW Beeston, ed. Proceedings Bowen Basin Sympo- Kellogg DW, EL Taylor 2004 Evidence of oribatid mite detritivory sium 2000, Geological Society of Australia, Rockhampton. in Antarctica during the late Paleozoic and Mesozoic. J Paleontol Foster CB 1979 Permian plant microfossils of the Blair Athol Coal 78:1146–1153. Measures, Baralaba Coal Measures, and basal Rewan Formation of Klavins SD, EL Taylor, M Krings, TN Taylor 2001 An unusual, Queensland. Geol Surv Queensl Publ 372, Palaeontol Pap 45:1–244. structurally preserved ovule from the Permian of Antarctica. Rev Galtier J, TL Phillips 1999 The acetate peel technique. Pages 67–70 in Palaeobot Palynol 115:107–117. TP Jones, NP Rowe, eds. Fossil plants and spores: modern techniques. Laurie JR, S Bodorkos, RS Nicoll, JL Crowley, DJ Mantle, AJ Mory, Geological Society, London. GR Wood, et al 2016 Calibrating the middle and late Permian 538 INTERNATIONAL JOURNAL OF PLANT SCIENCES

palynostratigraphy of Australia to the geologic time-scale via U-Pb and its Arctic territories. Geological Society of London Special Pub- zircon CA-IDTIMS dating. Aust J Earth Sci 63:701–730. lication 434, London. Lindström S, S McLoughlin, AN Drinnan 1997 Intraspecific variation McManus HA, EL Taylor, TN Taylor, JW Collinson 2002 A petri- of taeniate bisaccate pollen within Permian glossopterid sporangia, fied Glossopteris flora from Collinson Ridge, central Transantarctic from the Prince Charles Mountains, Antarctica. Int J Plant Sci Mountains; Late Permian or Early Triassic? Rev Palaeobot Palynol 158:673–684. 120:233–246. Lyons PC 2000 Funginite and secretinite: two new macerals of the McMinn A 1985 Palynostratigraphy of the Middle Permian coal se- inertinite maceral group. Int J Coal Geol 44:95–98. quences of the Sydney Basin. Aust J Earth Sci 32:301–309. Mackowsky M-Th 1982 Maceral analysis on polished surfaces of Metcalfe I, J Crowley, RS Nicoll, M Schmitz 2015 High-precision particulate coal samples. Pages 308–311 in E Stach, M-Th Mac- U-Pb CA-TIMS calibration of Middle Permian to Lower Triassic kowsky, M Teichmüller, GH Taylor, D Chandra, R Teichmüller, sequences, mass extinction and extreme climate-change in eastern eds. Stach’s textbook of coal petrology: 3rd revised and enlarged edi- Australian Gondwana. Gondwana Res 28:61–81. tion. Borntraeger, Berlin. Muhaidat R, RF Sage, NG Dengler 2007 Diversity of Kranz anatomy Maheshwari HK 1972 Permian wood from Antarctica and revision of and biochemistry in C4 eudicots. Am J Bot 94:362–381. some Lower Gondwana wood taxa. Palaeontographica 138B:1–43. Mussa D 1978 On the anatomy of wood showing affinities with the McCoy F 1847 On the fossil botany and zoology of the rocks asso- genus Vertebraria Royle, from the Irati Formation, State of São ciated with the coal in Australia. Ann Mag Nat Hist 20:145–157. Paulo, Brazil. Bol Inst Geosci 9:153–201. McLoughlin S 1990a Some Permian glossopterid fructifications and ——— 1986 Eustelos Gondwãnicos de medulas diafragmadas e a sua leaves from the Bowen Basin, Queensland, Australia. Rev Palaeobot posição estratigrafica. Bol Inst Geosci 17:11–26. Palynol 62:11–40. Mussa D, RG de Carvalho, PR Santos 1980 Estudo estratigráfico e ——— 1990b Late Permian glossopterid fructifications from the paleoecológico em ocorréncias fossilíferas da Formacão lrati, Bowen and Sydney Basins, eastern Australia. Geobios 23:283–297. Estado de São Paulo, Brasil. Bol Inst Geoci 11:142–149. ——— 1990c Palaeobotany and palaeoenvironments of Permian strata, Mustoe GE 2017 Wood petrifaction: a new view of permineralization Bowen Basin, Queensland. PhD thesis, University of Queensland, and replacement. Geosciences 119:1–17. doi:10.3390/geosciences Brisbane, Australia. 7040119. ——— 1992 Late Permian plant megafossils from the Bowen Basin, Neish PG, AN Drinnan, DJ Cantrill 1993 Structure and ontogeny of Queensland, Australia: pt 1. Palaeontographica 228B:105–149. Vertebraria from silicified Permian sediments in East Antarctica. ——— 1993 Plant fossil distributions in some Australian Permian Rev Palaeobot Palynol 79:221–244. non-marine sediments. Sed Geol 85:601–619. Nishida H, KB Pigg, K Kudo, JF Rigby 2007 New evidence of repro- ——— 1994a Late Permian plant megafossils from the Bowen Ba- ductive organs of Glossopteris based on permineralized fossils from sin, Queensland, Australia: pt 2. Palaeontographica 231B:1–29. Queensland, Australia. I. Ovulate organ Homevaleia gen. nov. J Plant ——— 1994b Late Permian plant megafossils from the Bowen Ba- Res 120:539–549. sin, Queensland, Australia: pt 3. Palaeontographica 231B:31–62. ——— 2014 New evidence of the reproductive organs of Glossopteris ——— 2011 Glossopteris: insights into the architecture and rela- based on permineralized fossils from Queensland, Australia. II. tionships of an iconic Permian Gondwanan plant. J Bot Soc Bengal Pollen-bearing organ Ediea gen. nov. J Plant Res 127:233–240. 65:93–106. Pant DD, KL Gupta 1971 Cuticular structure of some Indian Lower ——— 2012 Two new Senotheca (Glossopteridales) species from the Gondwana species of Glossopteris Brongniart. Pt 2. Palaeonto- Sydney Basin, Australia, and a review of the genus. Rev Palaeobot graphica 132B:130–152. Palynol 171:140–151. Pant DD, DD Nautiyal 1960 Some seeds and sporangia of Glossop- ——— 2016 A new genus of glossopterid fructifications from the teris flora from Raniganj Coalfield, India. Palaeontographica 107B: Artinskian–Changhsingian of eastern Australia. Ameghiniana 53:586– 41–64. 598. Pant DD, VK Singh 1987 Xylotomy of some woods from Raniganj McLoughlin S, AN Drinnan 1996 Anatomically preserved Noegge- Formation (Permian), Raniganj Coalfield, India. Palaeontographica rathiopsis leaves from east Antarctica. Rev Palaeobot Palynol 92:207– 203B:1–82. 227. Philippe M 1993 Nomenclature générique des trachéidoxyles fossiles ——— 1997 Revised stratigraphy of the Permian Bainmedart Coal mésozoïques à champs araucarioïdes. Taxon 42:74–80. Measures, northern Prince Charles Mountains, East Antarctica. Pigg KB 1990 Anatomically preserved Glossopteris foliage from the Geol Mag 134:335–353. central Transantarctic Mountains. Rev Palaeobot Palynol 66:105–127. McLoughlin S, B Bomfleur, AN Drinnan 2018 Pachytestopsis taylor- Pigg KB, S McLoughlin 1997 Anatomically preserved Glossopteris iorum gen. et sp. nov., an anatomically preserved glossopterid seed leaves from the Bowen and Sydney basins, Australia. Rev Palaeobot from the Lopingian of Queensland, Australia. Pages 155–178 in Palynol 97:339–359. M Krings, CJ Harper, NR Cúneo, GW Rothwell, eds. Transfor- Prasad MNV 1982 An anatomical synopsis of Indian Palaeozoic mative paleobotany: papers to commemorate the life and legacy of gymnospermous woods. Rev Palaeobot Palynol 38:119–156. Thomas N. Taylor. Elsevier, Amsterdam. Prevec R 2011 A structural re-interpretation and revision of the type McLoughlin S, AN Drinnan, BJ Slater, J Hilton 2015 Paurodendron material of the glossopterid ovuliferous fructification Scutum from stellatum: a new Permian permineralized herbaceous lycopsid from South Africa. Palaeont Afr 46:1–19. the Prince Charles Mountains, Antarctica. Rev Palaeobot Palynol 220:1– ——— 2014 Elatra: a glossopterid fructification with a bipartite, 15. hooded wing from the lower Permian of Madagascar and South McLoughlin S, S Lindström, AN Drinnan 1997 Gondwanan floristic Africa. Rev Palaeobot Palynol 210:119–139. and sedimentological trends during the Permian-Triassic transition: Prevec R, RA Gastaldo, J Neveling, SB Reid, CV Looy 2010 An au- new evidence from the Amery Group, northern Prince Charles Moun- tochthonous glossopterid flora with latest Permian palynomorphs tains, East Antarctica. Antarc Sci 9:281–298. and its depositional setting in the Dicynodon Assemblage Zone of McLoughlin S, C Strullu-Derrien 2016 Biota and palaeoenvironment the southern Karoo Basin, South Africa. Palaeogeogr Palaeoclimatol of a high middle-latitude Late Triassic peat-forming ecosystem from Palaeoecol 292:391–408. Hopen, Svalbard Archipelago. Pages 87–112 in BP Kear, J Lindgren, Prevec R, CC Labandeira, J Neveling, RA Gastaldo, CV Looy, M JH Hurum, J Milàn, V Vajda, eds. Mesozoic biotas of Scandinavia Bamford 2009 Portrait of a Gondwanan ecosystem: a new Late MCLOUGHLIN ET AL.—PERMIAN PERMINERALIZED PEAT FROM AUSTRALIA 539

Permian fossil locality from KwaZulu-Natal, South Africa. Rev Shi GR, S McLoughlin 1997 Permian stratigraphy, sedimentology Palaeobot Palynol 156:454–493. and palaeontology of the southern Sydney Basin, eastern Australia: Prevec R, S McLoughlin, MK Bamford 2008 Novel wing morphology a field excursion guide. Deakin University, School of Aquatic Science revealed in a South African ovuliferous glossopterid fructification. and Natural Resources Management, Technical Paper 2:1–59. Rev Palaeobot Palynol 150:22–36. Shi GR, JB Waterhouse, S McLoughlin 2010 The Lopingian of Aus- Retallack GJ 1980 Late Carboniferous to Middle Triassic megafossil tralasia: a review of biostratigraphy, correlations, palaeogeography floras from the Sydney Basin. Pages 384–430 in CHerbert,RJHelby, and palaeobiogeography. Geol J 45:230–263. eds. A guide to the Sydney Basin. Geol Surv N S W Bull 26 Sydney, Shivanna M, S Murthy, S Gautam, PA Souza, PS Kavali, MEC Australia. Bernardes-de-Oliveira, Ram-Awatar, CM Félix 2017 Macroscopic Ricardi-Branco F, M Arai, O Rösler 2002 Megaspores from coals of charcoal remains as evidence of wildfire from late Permian Gondwana the Triunfo Member, Rio Bonito Formation (Lower Permian), north- sediments of India: further contribution to global fossil charcoal data- eastern Paraná State, Brazil. An Acad Bras Cienc 74:491–503. base. Palaeoworld 26:638–649. Rigby JF 1961 The discovery of Glossopteris fructifications in New Slater BJ, S McLoughlin, J Hilton 2011 Guadalupian (Middle Perm- South Wales. Aust J Sci 23:230. ian) megaspores from a permineralised peat in the Bainmedart Coal ——— 1964 The Lower Gondwana flora of the Illawarra Coal Measures, Prince Charles Mountains, Antarctica. Rev Palaeobot Paly- Measures, Wollongong, New South Wales, Australia. Pages 17–25 nol 167:140–155. in DRS Mehta, F Ahmad, eds. Report of the Twenty-Second Session, ——— 2012 Animal-plant interactions in a Middle Permian per- International Geological Congress, New Dehli, 9. mineralised peat of the Bainmedart Coal Measures, Prince Charles ——— 1966 Some Lower Gondwana articulates from New South Mountains, Antarctica. Palaeogeogr Palaeoclimatol Palaeoecol 363– Wales. Pages 48–54 in KR Surange, ed. Symposium on floristics 364:109–126. and stratigraphy of Gondwanaland. Birbal Sahni Institute of Palaeo- ——— 2015 A high-latitude Gondwanan lagerstätte: the Permian botany, Lucknow, India. permineralised peat biota of the Prince Charles Mountains, Ant- ——— 1972 The flora of the Kaloola Member of the Baralaba Coal arctica. Gondwana Res 27:1446–1473. Measures, central Queensland. Geol Surv Queensl Publ 352, Palae- Smith ME, TW Henkel, JA Rollins 2015 How many fungi make ontol Pap 26:1–12. sclerotia? Fungal Ecol 13:211–220. Rößler R, M Philippe, JHA van Konijnenburg-van Cittert, S Mc- Smoot EL, TN Taylor 1986a Evidence of simple polyembryony in Loughlin, J Sakala, G Zijlstra, M Bamford, et al 2014 Which Permian seeds from Antarctica. Am J Bot 73:1079–1081. name(s) should be used for Araucaria-like fossil wood? results of a ——— 1986b Structurally preserved plant fossils from Antarctica. poll. Taxon 63:177–184. II. A Permian moss from the Transantarctic Mountains. Am J Bot Royle JF 1834 Illustrations of the botany and other branches of the 73:1683–1691. natural history of the Himalayan Mountains and of the flora of Stubblefield SP, TN Taylor 1986 Wood decay in silicified gymno- Cashmere. Vol 2. Allen, London. sperms from Antarctica. Bot Gaz 147:116–125. Ryberg PE 2010 Lakkosia kerasata gen. et sp. nov., a permineralized Sutton MD, IA Rahman, RJ Garwood 2014 Techniques for virtual megasporangiate glossopterid structure from the central Trans- palaeontology: new analytical methods in earth and environmental antarctic Mountains, Antarctica. Int J Plant Sci 171:332–344. science. Wiley, Chichester. Ryberg PE, EL Taylor 2013 Lonchiphyllum aplospermum gen. et sp. Tadros NZ 1995 Sydney-Gunnedah Basin overview. Pages 163–175 nov.: an anatomically preserved glossopterid megasporophyll from in CR Ward, HJ Harrington, CW Mallett, JW Beeston, eds. Geol- the Upper Permian of Skaar Ridge, Transantarctic Mountains, ogy of Australian coal basins. Geological Society of Australia Coal Antarctica. Int J Plant Sci 174:396–405. Geology Group Special Publication 1, Sydney. Ryberg PE, EL Taylor, TN Taylor 2012 Antarctic glossopterid di- Tavares TMV, R Rohn, R Rößler, R Noll 2014 Petrified Marattiales versity on a local scale: the presence of multiple megasporophyll pinnae from the Lower Permian of north-western Gondwana (Par- genera, Upper Permian, Mt. Achernar, Transantarctic Mountains, naíba Basin, Brazil). Rev Palaeobot Palynol 201:12–28. Antarctica. Am J Bot 99:1531–1540. Taylor EL, TN Taylor 1987 An ovule-bearing reproductive organ Sahni B, TCN Singh 1926 On some new specimens of Dadoxylon arberi from the Permian of Antarctica. Am J Bot 74:691. Sew. from New South Wales and Queensland. J Ind Bot Soc 5:103–112. Taylor EL, TN Taylor, JW Collinson 1989 Depositional setting and pa- Schimper WP 1870 Traité de paléontologie végétale ou la flore du leobotany of Permian and Triassic permineralized peat from the central monde primitif. Vol 2. J. B. Baillière et fils, Paris. Transantarctic Mountains, Antarctica. Int J Coal Geol 12:657–679. Schopf JM 1965 Anatomy of the axis in Vertebraria. Pages 217–228 Tian BL, SJ Wang, YT Gao, GR Chen, H Zhao 1996 Flora of in JB Hadley, ed. Geology and paleontology of the Antarctic. Palaeozoic coal balls in China. Palaeobotanist 45:247–254. American Geophysical Union, Washington, DC. Townrow JA 1968 A fossil Selaginella from the Permian of New ——— 1970 Petrified peat from a Permian coal bed in Antarctica. South Wales. J Linn Soc Lond Bot 61:13–23. Science 169:274–277. Veevers JJ 2000 Billion-year earth history of Australia and neighbours ——— 1982 Forms and facies of Vertebraria in relation to Gond- in Gondwanaland. GEMOC Press, Sydney. wana coal. Pages 37–62 in MD Turner, JE Splettstoesser, eds. Geol- Waschbusch P, RJ Korsch, C Beaumont 2009 Geodynamic model- ogy of the Central Transantarctic Mountains. American Geophys- ling of aspects of the Bowen, Gunnedah, Surat and Eromanga basins ical Union, Antarctic Research Series 36. from the perspective of convergent margin processes. Aust J Earth Sci Schwendemann AB 2012 Permian photosynthetic pathways: form, 56:309–334. function, and stable carbon isotopes of Antarctic Glossopteris Weaver L, S McLoughlin, AN Drinnan 1997 Fossil woods from the Up- leaves. Abstracts of the Botanical Society of America Conference, per Permian Bainmedart Coal Measures, northern Prince Charles August 2, Providence, RI, USA. Abstract 331. Mountains, East Antarctica. AGSO J Aust Geol Geophys 16:655–676. Schwendemann AB, A-L Decombeix, EL Taylor, TN Taylor 2010 White ME 1978 Reproductive structures of the Glossopteridales in Collinsonites schopfii gen. et sp. nov., a herbaceous lycopsid from the Australian Museum. Rec Aust Mus 31:473–504. the Upper Permian of Antarctica. Rev Palaeobot Palynol 158:291– Willard DA, WA DiMichele, DL Eggert, JC Hower, CB Rexroad, AC 297. Scott 1995 Paleoecology of the Springfield Coal Member (Desmoi- Scurfield G, ER Segnit 1984 Petrifaction of wood by silica minerals. nesian, Illinois Basin) near the Leslie Cemetery Paleochannel, south- Sediment Geol 39:149–167. western Indiana. Int J Coal Geol 27:59–98.