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Extending the Range of Derived Late Paleozoic Conifers: Lebowskia gen. nov. (Majonicaceae)
Abstract and Figures
Phylogenetic analysis suggests that the conifer families Majonicaceae and Ullmanniaceae (voltzian Voltziales), known from the equatorial Late Permian Euro-American flora province, arose from a member of a paraphyletic group of walchian Voltziales commonly referred to as walchian conifers. The Majonicaceae and Ullmanniaceae are more derived in that they have fused female reproduction organs and a more advanced reproduction strategy that involves a pollen tube. Until recently, it has not been possible to establish with accuracy when these conifers originated or when they started their rise to dominance over the walchian conifers. Findings from late Early to early Middle Permian localities in north-central Texas prove that radiation in these conifer lineages occurred significantly earlier than previously thought. The natural genus Lebowskia (Majonicaceae) from the Early Lower Pease River flora is described and compared with Late Permian taxa. It confirms that the Majonicaceae were already well differentiated during Early Permian times and considerably extends their geographic and temporal range. It shows that structural evolution and diversification among these conifer taxa took place before late Early Permian. Evolution and migration of conifers in the Late Paleozoic tropical regions seems to have been strongly influenced by the increasingly drier climate.
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... As a result, there was a notable vegetation turnover, starting during the Late Pennsylvanian, which gradually replaced wetland forests dominated by plants adapted to humid conditions (sensu Cecil, 2003), with a vegetation dominated by drought tolerant plants. This stepwise transition gradually spread from western to eastern Pangea, reaching Cathaysia during the middle Permian, with the palaeotropical coal forests decline (e.g., Wang and Chen, 2001;Cleal and Thomas, 2005;DiMichele et al., 2001DiMichele et al., , 2009Looy, 2007;Montañez, 2016;DiMichele, 2014;Looy and Stevenson, 2014;Looy and Duijnstee, 2020;Richey et al., 2020). However, our understanding of the dynamics of this flora turnover during the Cisuralian (early Permian) is limited due to the scarcity of well-dated diverse plant fossil assemblages (e.g., Looy, 2007;Marchetti et al., 2015aMarchetti et al., , 2022Cleal, 2018;Forte et al., 2017Forte et al., , 2018aForte et al., , 2018bForte et al., , 2019Forte et al., , 2023aForte et al., , 2023bLooy and Duijnstee, 2020;Forte and Kustatscher, 2023). ...
... This stepwise transition gradually spread from western to eastern Pangea, reaching Cathaysia during the middle Permian, with the palaeotropical coal forests decline (e.g., Wang and Chen, 2001;Cleal and Thomas, 2005;DiMichele et al., 2001DiMichele et al., , 2009Looy, 2007;Montañez, 2016;DiMichele, 2014;Looy and Stevenson, 2014;Looy and Duijnstee, 2020;Richey et al., 2020). However, our understanding of the dynamics of this flora turnover during the Cisuralian (early Permian) is limited due to the scarcity of well-dated diverse plant fossil assemblages (e.g., Looy, 2007;Marchetti et al., 2015aMarchetti et al., , 2022Cleal, 2018;Forte et al., 2017Forte et al., , 2018aForte et al., , 2018bForte et al., , 2019Forte et al., , 2023aForte et al., , 2023bLooy and Duijnstee, 2020;Forte and Kustatscher, 2023). ...
... The other dwarf shoots are characterized by several free or partly fused lobes (up to 8) with rounded (Plate I, 23-25) or pointed (Plate I, 22) apices, with a distinct stalk-like base or with the basal part missing (Plate I, 25). These dwarf shoots resemble majonicacean ones, such as Majonica alpina Clement-Westerhof, 1987, Manifera talaris Looy et Stevenson, 2014, and Lebowskia grandifolia Looy, 2007(Clement-Westerhof, 1987, 1988Looy, 2007;Plate I, 16-19). Additionally, dispersed seeds with so far unknown affinity are also present. ...
... In contrast, the other Tregiovo conifer taxa are assigned to genera with a wide paleogeographic and temporal range. The presence of broad-leaved conifers in the Tregiovo flora (Marchetti et al., 2015(Marchetti et al., , 2022Forte et al., 2018aForte et al., , 2019, this study) is of particular interest, since these derived forms were previously considered common from the Lopingian on (e.g., Broutin and Kerp, 1994;Forte et al., 2017), although they were recently reported from early Permian of western (e.g., Looy, 2007;Looy and Duijnstee, 2020) and previously, from eastern coasts of tropical Pangea (e.g., Broutin and Kerp, 1994). Ovuliferous dwarf shoots of conifers have been recovered from the Tregiovo assemblages as well and show a great morphological variability (e.g., Forte et al., 2017). ...
... The macromorphological characters, as well as the dominance of xerophytic gymnosperms (i.e., seed ferns and conifers) in macro-and microfossil assemblage, suggest that at Tregiovo conifers were adapted to a somewhat arid environment (Forte et al., 2018a. Similar features have been observed in conifer specimens from time equivalent Lower Pease River Flora (Looy, 2007). These xerophytic features may have been quite common in Cisuralian plants occupying extrabasinal and more drained environments (DiMichele et al., 2001). ...
... It has been postulated that a stepwise and diachronically replacement of mesophytic floras by xerophytic community started in western North America and proceeded toward central and eastern Pangea (e.g.,DiMichele et al., 2001DiMichele et al., , 2018DiMichele, 2014;Looy et al., 2014;Falcon-Lang et al., 2017). The only areas testifying this transition are two western Euramerican Kungurian floras (e.g.,DiMichele et al., 2001DiMichele et al., , 2004Looy, 2007;Looy and Duijnstee, 2020) and the Tregiovo flora(Forte et al., 2017(Forte et al., , 2018a. The co-occurrence of walchian and voltzian conifers in the Tregiovo flora is one of the oldest recorded so far(Forte et al., 2017). ...
... The putative assignment to Pseudovoltzia is based on macromorphological similarity to Pseudovoltzia liebeana (e.g., Schweitzer, 1962Schweitzer, , 1963Schweitzer, , 1986Clement-Westerhof, 1987, 1988Uhl & Brandt, 2004; Tab. 1) and the cooccurrence of heterophylly, with shorter and longer ribbonlike leaves on the same shoot (e.g., Schweitzer, 1962Schweitzer, , 1963Schweitzer, , 1986. Pseudovoltzia is well-known from the Lopingian of Europe (e.g., Schweitzer, 1962Schweitzer, , 1963Clement-Westerhof, 1987, 1988Kustatscher et al., 2012) although the first occurrence of the genus has been pushed back to the middle Permian, with the occurrence of Pseudovoltzia sapflorensis Looy & Duijnstee, 2020(Looy, 2007Looy & Duijnstee, 2020). Long, linear leaves with round apices are also typical of Quadrocladus from the late Permian of Central Europe and Russia (e.g., Mädler, 1957;Schweitzer, 1962Schweitzer, , 1963Schweitzer, , 1986Meyen, 1997;Uhl & Kerp, 2005;Kustatscher et al., 2012;Tab. ...
... Long, linear leaves with round apices are also typical of Quadrocladus from the late Permian of Central Europe and Russia (e.g., Mädler, 1957;Schweitzer, 1962Schweitzer, , 1963Schweitzer, , 1986Meyen, 1997;Uhl & Kerp, 2005;Kustatscher et al., 2012;Tab. 1) and Lebowskia grandifolia Looy, 2007 and Johniphyllum multinerve Looy & Duijnstee, 2020 from the Early-Middle Permian of north-central Texas (Looy, 2007;Looy & Duijnstee, 2020;Tab. 1). ...
... Long, linear leaves with round apices are also typical of Quadrocladus from the late Permian of Central Europe and Russia (e.g., Mädler, 1957;Schweitzer, 1962Schweitzer, , 1963Schweitzer, , 1986Meyen, 1997;Uhl & Kerp, 2005;Kustatscher et al., 2012;Tab. 1) and Lebowskia grandifolia Looy, 2007 and Johniphyllum multinerve Looy & Duijnstee, 2020 from the Early-Middle Permian of north-central Texas (Looy, 2007;Looy & Duijnstee, 2020;Tab. 1). ...
The sedimentary succession of the Sinich/Sinigo Basin is one of the oldest sedimentary intercalations of the Cisuralian (lower Permian) Athesian Volcanic Group of the Bozen/Bolzano area. The plant remains that were deposited in its alluvial and lacustrine sediments are middle Kungurian in age and are characterized by a wide variety of preservation types. The nearly 600 specimens from Sinich/Sinigo include permineralized stems, compressions/impressions and casts/molds, which belong to various plant groups, such as putative lycopsids, sphenophytes, ferns, seed ferns, cordaitaleans and conifers. Strata of the Sinich/Sinigo Basin yield one of the richest and best-documented Kungurian plant assemblages of eastern paleoequatorial Pangea. The conifers are represented by both walchian and more derived voltzian Voltziales, forming the earliest co-occurrence of these two groups in eastern Pangea. The three-dimensional preservation mode revealed xeromorphic features in more than one conifer species, such as the presence of fleshy and "deciduous" leaves in both walchian and voltzian conifers. These morphological features were probably more common during the early Permian, being an adaptation to aridity. The comparison of the Sinich/Sinigo collection with other Kungurian plant assemblages strengthens the assumption of more widespread semi-arid to arid conditions in the middle-late Kungurian of the Southern Alps, whereas the strata and the presence of hygrophytic elements indicate that increased rainfall and flooding events could have occasionally occurred.
... Sin embargo, en este caso al no poder observar escamas fértiles y por consiguiente las áreas de unión de los óvulos, así como su arreglo con respecto a las escamas estériles, se hace imposible la identificación en un rango taxonómico inferior por lo cual únicamente se asigna a nivel de familia. Este es un elemento típico del Paleozoico superior de Euroamérica, sobre todo en su parte ecuatorial (Looy, 2007). ...
... En total, en la Formación Tuzancoa se identificaron seis ordenes, 18 géneros y 10 especies; todos estos taxones son típicos de finales del Paleozoico y adaptados a un clima generalmente húmedo con periodos de estrés hídrico (Thomas, 1978;Phillips y DiMichele, 1992;DiMichele et al., 2006;Looy, 2007;Taylor et al., 2009;DiMichele et al., 2010;Wilson et al., 2017). Sin embargo, las localidades La Virgen y San Mateo 2 que tienen material autóctono presentan mayor similitud, ya que comparten casi el 40 % de los taxa (Tabla 1). ...
... Bjuvia Florin y Velascoa Flores-Barragan y Ortega-Chavez) (Flores-Barragan y . Por su parte, el ambiente deltaico distal hasta ahora propuesto para la Formación Tuzancoa, junto con elementos florísticos autóctonos abundantes como Comia, así como la disminución de géneros higrófilos como Calamites, Sigillaria y Asterotheca (Thomas, 1978;Looy, 2007;Phillips y DiMichele, 1992;Taylor et al., 2009;DiMichele et al., 2006;DiMichele et al., 2010;Wilson et al., 2017) indican un clima diferente para ambas unidades y que si bien no son correlacionables permiten dar una visión más general de la vegetación presente a finales del Paleozoico en el territorio nacional. ...
La paleoflora de la Formación Tuzancoa ha sido estudiada desde mediados del siglo pasado. Sin embargo, el constante descubrimiento de nuevos elementos florísticos y/o localidades hace necesaria una reevaluación del conocimiento actual de la paleoflora de esta formación. El objetivo de este trabajo es dar a conocer los nuevos reportes paleoflorísticos de tres localidades de la Formación Tuzancoa, así como analizar su distribución geográfica, cronológica y su relación con otras floras coetáneas de México. Las localidades aquí estudiadas se denominan Calnali 2, La Virgen y San Mateo 2, siendo esta última una nueva localidad. En la primera localidad se identificaron seis órdenes (Equisetales, Glossopteridales, Lepidodendrales, Marattiales, Peltaspermales y Voltziales). Mientras que en La Virgen y San Mateo 2 se identificaron cuatro órdenes (Equisetales, Lepidodendrales, Marattiales, y Peltaspermales). Los nuevos reportes corresponden a una familia, dos afinidades, cinco géneros y siete especies; de este conjunto, destacan cinco taxones que son nuevos reportes para la República Mexicana y/o importantes taxonómicamente y estos corresponden a: Majonicaceae, Odontopteris cf. brardii, Mariopteris, Taeniopteris feddeni y T. tenuis. Majonicaceae es representada por una estructura reproductora femenina probablemente relacionada con la especie Calnalia hidalguensis; Odontopteris cf. brardii es un helecho que se caracteriza por la ausencia de una vena media en sus pínnulas; Mariopteris es un helecho con pínnulas con distintos grados de fusión; Taeniopteris feddeni corresponde a una hoja entera de gran tamaño, con más de cinco cm de ancho, con una densidad de 20 a 22 venas secundarias por cm; y por último, Taeniopteris tenuis es un hoja entera con menos de cinco cm de ancho que presenta un arreglo único en su venación secundaria, con una densidad de 28 a 30 venas por cm. Estos nuevos hallazgos aumentan sustancialmente la diversidad florística de la formación y permiten establecer, junto con la litología, un ambiente transicional en Calnali 2 y un ambiente continental en La Virgen y San Mateo 2. Los rangos estratigráficos y de distribución de los taxones sugieren una edad de Pensilvánico–Pérmico inferior para los estratos portadores de plantas, además se infiere una posible afinidad geográfica con el reino Euroamericano. Por último, al comparar el listado florístico de la Formación Tuzancoa con otras unidades coetáneas con reportes de flora fósil como son las formaciones Matzitzi (Mt), Paso Hondo (Ph), Olinalá (Ol) y el Grupo Patlanoaya (Pt) se tiene que, en estas últimas (Ph, Ol y Pt) se observa una similitud mínima debido al pobre registro en relación con la Formación Tuzancoa. Con respecto a la Formación Matzitzi, las plantas indican características propias de ambientes diferentes: continental para Matzitzi y de transición-continental para Tuzancoa. Todos estos nuevos aportes nos ayudan a comprender mejor los ecosistemas terrestres de finales del Paleozoico en el margen ecuatorial occidental de Euroamérica.
... The macromorphology and micromorphology of the seed cones of V. recubariensis are here described for the first time. The general loose organization of the seed cone of V. recubariensis, with bract-dwarf shoot complexes loosely and helically arranged around a central stout axis, resembles that of Majonicaceae such as the Permian taxa Lebowskia grandifolia Looy, 2007, V. hexagona (Bischoff) Geinitz, 1861(e.g., Schweitzer 1996Brandt 2010), and Pseudovoltzia liebeana (Geinitz) Florin, 1927(e.g., Schweitzer 1996. However, some of these Permian taxa were characterized by the presence of not only terminal cones but also fertile zones (e.g., Schweitzer 1996; Looy 2007; Looy and Duijnstee 2020; table 1), which have not been observed in V. recubariensis (table 1). ...
... However, Pseudovoltzia is characterized by a higher degree of fusion of the lobes than observed in cf. Voltzia sp. 1 and other Voltzia species (e.g., Geinitz 1861; Clement-Westerhof 1987, 1988Schweitzer 1996;Meyen 1997;Looy 2007;Looy and Duijnstee 2020). Moreover, in both V. hexagona and P. liebeana dwarf shoots, two vegetative scales occur between the three sporophylls, resulting in a five-lobed dwarf shoot. ...
... comb., is proposed. The partial fusion of the fertile/sterile scales (less than one-third of the scale length) is a common characteristic in Permian species such as L. grandifolia, Majonica alpina, P. liebeana, and Pseudovoltzia sapflorensis (e.g., Geinitz 1880 ;Florin 1927;Clement-Westerhof 1987, 1988Uhl and Brandt 2004;Looy 2007;Looy and Duijnstee 2020). A remarkable degree of fusion between fertile and sterile scales is present in Middle-Late Triassic species such as V. coburgensis (e.g., von Schauroth 1852; Mägdefrau 1953; Kelber 1990Kelber , 1998Schweitzer 1996). ...
... The family Majonicaceae was originally described from the upper Permian (Wuchiapingian, Lopingian) of the Southern Alps. The earliest records of Majonicaceae are Lebowskia grandifolia Looy 2007 and Manifera talaris, both from north central Texas (USA). These taxa were instituted for foliage and ovuliferous cones, and for foliage and dwarf-shoots, respectively. ...
... These taxa were instituted for foliage and ovuliferous cones, and for foliage and dwarf-shoots, respectively. They are dated as late Kungurian to Wordian (late Cisuralian to early Guadalupian; early-middle Permian) and latest Kungurian to Roadian (Looy 2007;Looy and Stevenson 2014). These earliest records show that the Majonicaceae can be traced back to the late early Permian and that they were widespread, albeit rare. ...
Bulk macerations of a mesoflora from the late Permian Zechsteinmergel of Gera-Trebnitz, east Thuringia, yielded – apart from a number of typical Zechstein taxa – two conifers previously unrecorded from the German Zechstein Basin. These two conifer genera, Ortiseia Florin 1964 Florin, R. 1964. Über Ortiseia leonardii n. gen. et sp., eine Konifere aus den Grödener Schichten in Alto Adige (Südtirol). Mem Geopaleont Univ Ferrara. 1(1):3–11. [Google Scholar] and Majonica Clement-Westerhof 1987, were so far only known from northern Italy. The type species of Culmitzschia Ullrich 1964 Ullrich, H. 1964. Zur Stratigraphie und Paläontologie der marin beeinflußten Randfazies des Zechsteinbeckens in Ostthüringen und Sachsen. Freiberger Forsch-H C. 169:1–163. [Google Scholar] (C. florinii Ullrich 1964 Ullrich, H. 1964. Zur Stratigraphie und Paläontologie der marin beeinflußten Randfazies des Zechsteinbeckens in Ostthüringen und Sachsen. Freiberger Forsch-H C. 169:1–163. [Google Scholar]), a broad-leaved conifer from the southern margin of the Zechstein Basin, appears to be a synonym of Ortiseia leonardii Florin 1964 Florin, R. 1964. Über Ortiseia leonardii n. gen. et sp., eine Konifere aus den Grödener Schichten in Alto Adige (Südtirol). Mem Geopaleont Univ Ferrara. 1(1):3–11. [Google Scholar], the type species of Ortiseia Florin 1964 Florin, R. 1964. Über Ortiseia leonardii n. gen. et sp., eine Konifere aus den Grödener Schichten in Alto Adige (Südtirol). Mem Geopaleont Univ Ferrara. 1(1):3–11. [Google Scholar], the latter name having priority. All bona fide species attributed to Culmitzschia after 1964 Florin, R. 1964. Über Ortiseia leonardii n. gen. et sp., eine Konifere aus den Grödener Schichten in Alto Adige (Südtirol). Mem Geopaleont Univ Ferrara. 1(1):3–11. [Google Scholar] differ from Culmitzschia as defined by Ullrich (=Ortiseia) and are transferred to Ullrichia gen. nov., resulting in the new combinations U. intermedia (Florin 1939) Kerp comb. nov., U. laxifolia (Florin 1939) Kerp comb. nov. and U. mucronata (Florin 1939) Kerp comb. nov.
... During the early Permian, gymnosperms dominated plant fossil assemblages were recorded from several palaeotropical localities, that testify the radiation of "new" gymnosperm groups (e.g., cycads, ginkgophytes, walchian and voltzialean conifers) that became more abundant and widespread from the middle-late Permian to the Mesozoic (e.g., Hernandez-Castillo et al., 2003;Looy, 2007;DiMichele et al., 2008;Forte et al., 2017;Looy and Duijnstee, 2020). The palaeobotanical composition of the two assemblages (A and B) of Tregiovo (Fig. 2) show similarities with coeval floras of North America (Marchetti et al., 2015(Marchetti et al., , 2022Forte et al., 2017Forte et al., , 2018aForte et al., , 2019 and reflect the trend of an increasing aridity during the Cisuralian (early Permian) at low latitudes (e.g., Montañez et al., 2007;Tabor and Poulsen, 2008;Horton et al., 2012;Montañez and Poulsen, 2013;Michel et al., 2015). ...
The Tregiovo flora is one of the best documented and well-dated Kungurian floras of Euramerica. It fielded a rich and diverse plant fossil assemblage including voltzian and walchian conifers, peltasperm seed ferns, sphenopterids, putative ginkgophytes, ferns and horsetails. Here two taxa are described and discussed, Tregiovia furcata gen. et sp. nov. and Cordaites sp. The former, characterized by a bifurcating lamina with a distinct midrib, is of difficult botanical affinity, with the closest resemblance to Auritifolia anomala. If this similarity is confirmed, it would represent to the first comioid record in the Southern Alps and Europe. The two new taxa underline the bias of the fossil record for elements adapted to seasonally dry environments. A comparison with similar taxa of gymnosperm affinity show that the Cisuralian fossil record is still very scares in certain areas of Pangea such as the low and middle latitudes of Gondwana, eastern Gondwana and the high latitudes of Euramerica.
... In Sections 3.1 and 3.2, the TB-WP-FS scheme (i.e., described in the sidebar titled Toward a Unified Framework for Functional Characterization of Extinct Plants: The Trait-Based Whole-Plant Functional Strategy and Figure 1) is applied to late Paleozoic ever-wet tropical plants using the process-based paleo-ecosystem model Paleo-BGC (White Examples of parameters that can be directly measured on fossil leaves and stems and used to reconstruct quantitative primary functional traits. (a) Cuticle of Lebowskia grandifolia, Lower Pease River flora (Looy 2007), Univ. of Calif., Museum of Paleontology specimen #BP-42104-CS67-SSL1, used to measure stomatal density and geometry (see panel c) and calculate maximum stomatal conductance [g s,max (from Richey et al. 2020Richey et al. , 2021]. (b) Close-up of stomata from cuticle in panel a. ...
Terrestrial plants have transformed Earth's surface environments by altering water, energy, and biogeochemical cycles. Studying vegetation-climate interaction in deep time has necessarily relied on modern-plant analogs to represent paleo-ecosystems—as methods for reconstructing paleo- and, in particular, extinct-plant function were lacking. This approach is potentially compromised given that plant physiology has evolved through time, and some paleo-plants have no clear modern analog. Advancements in the quantitative reconstruction of whole-plant function provide new opportunities to replace modern-plant analogs and capture age-specific vegetation-climate interactions. Here, we review recent investigations of paleo-plant performance through the integration of fossil and geologic data with process-based ecosystem- to Earth system–scale models to explore how early vascular plants responded to and influenced climate. First, we present an argument for characterizing extinct plants in terms of ecological and evolutionary theory to provide a framework for advancing reconstructed vegetation-climate interactions in deep time. We discuss the novel mechanistic understanding provided by applying these approaches to plants of the late Paleozoic ever-wet tropics and at higher latitudes. Finally, we discuss preliminary applications to paleo-plants in a state-of-the-art Earth system model to highlight the potential implications of different plant functional strategies on our understanding of vegetation-climate interactions in deep time. ▪ For hundreds of millions of years, plants have been a keystone in maintaining the status of Earth's atmosphere, oceans, and climate. ▪ Extinct plants have functioned differently across time, limiting our understanding of how processes on Earth interact to produce climate. ▪ New methods, reviewed here, allow quantitative reconstruction of extinct-plant function based on the fossil record. ▪ Integrating extinct plants into ecosystem and climate models will expand our understanding of vegetation's role in past environmental change.
... Global range of taxa based on supplementary online material published by di Pasquo et al. (2015). For botanical affinity of Lueckisporites see Clement-Westerhof (1987) and Looy (2007). Abbreviations under botanical affinities: G-Gymnosperm. ...
... Walchian Conifers (Fig. 23) At least two, and possibly three, types of "walchian" conifers occur as a conspicuous part of the Kinney flora (Fig. 23). The reader is referred to Looy (2007) for a discussion of various conifer groups, the complexities of conifer taxonomy, and their phylogenetic relationships. assigned the Kinney conifer remains to two species, Walchia piniformis (Schlotheim) Sternberg and Hermitia (Walchia) cf. ...
Since their first appearance in the Middle-Late Silurian, land plants have played an increasingly important role in shaping terrestrial ecosystems and landscapes. It is difficult to overestimate their role because they form the framework for terrestrial ecosystems, provide habitats for terrestrial animals, form an important part of the food chain, affect weathering processes and have a direct impact on soil formation, and, last but not least, play a primary role in the oxygen/carbon cycles.
Early Permian (late Leonardian Series) plant assemblages from King, Knox, and Stonewall Counties of North-Central Texas are dominated by seed plants, some apparently congeneric with taxa heretofore known only from the Late Permian or the Mesozoic. Conifers are the dominant elements, including one or more species of Ullmannia, Pseudovoltzia liebeana , both known from the Late Permian Zechstein flora of Germany and England, Podozamites sp., characteristic of the Mesozoic, and Walchia sp., abundant in Early Permian floras. Locally common are Taeniopteris cf. eckardtii , a Zechstein species, an unidentified plant represented by pinnulelike laminae with fine parallel veins, similar to pinnules of some Mesozoic cycads, and calamite stems. Rarely encountered are leaf fragments of the Paleozoic ginkgophyte Dicranophyllum , flabellate ginkgophyte leaves, leaves with a broad midvein and narrow, fimbriate lamina, and Wattia , typical of the Early Permian. Associated with these foliar remains are ovulate reproductive structures including the presumed cycad megasporophyll Dioonitocarpidium , known only from the Mesozoic, a voltzialean cone scale similar to Swedenborgia , and a variety of seeds, some remarkably similar to Agathis , of Cretaceous age. The assemblage includes only rare scraps of foliage and seeds possibly attributable to the pteridophyllous elements (gigantopterids, callipterids, and ferns) that dominate the Permian. The fossil plants occur in multistorey, fining-upwards, tidal-channel deposits that also include pelecypods and fragmentary palaeoniscoid fish. The occurrence of derived lineages in xeric habitats during the Early Permian indicates that some supposed Mesozoic groups actually preceded and survived the end-Permian extinction, reappearing in basinal lowlands during the mid-Mesozoic.
The type species of the palynological form-genus Potonieisporites, P. novicus, can be considered to represent Late Carboniferous/Early Permian conifers, assignable to the Walchiaceae of the Euramerican floral province. Morphological and ultrastructural analysis of the species falsifies earlier concepts of a monosaccate organization and the presence of a distal germinal area. The species is characterized by a monosaccoid sexine expansion, cnmpletely filled with an alveolate infrastructure. A proximal aperture is distinct, but there is no evidence of distal specializations indicative of the outgrowth of a haustorial pollen tube; the species thus qualifies as prepollen. These characters are included in an emended diagnosis for the species. A restricted concept of an exclusively walchiaccous status for the form-genus Potonieisporites can not yet be proposed, mainly because of the lack of conclusive evidence on the botanical affinity and the morphologial/ultrastructural organization of similar pollen from the Gondwana floral province.