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Premise: In recent years, Doyleales have played an important role in the discussion and exploration of seed plant relationships and the origin of angiosperms. This order comprises a diversity of recently described genera with cupule‐bearing compound ovulate cones recovered from Early Cretaceous deposits in North America and Asia. Their relatively late appearance in the fossil record, stratigraphically near the appearance of angiosperms in the Early Cretaceous, has been noteworthy. Here, we report a new genus of Doyleales, Zirabia gen. nov. from the Early Jurassic of Iran, that was originally described as the ginkgophyte Karkenia. Methods: We reinvestigated material previously assigned to Karkenia cylindrica from the Lower Jurassic of the Zirab locality, Alborz Mountains, northern Iran. Results: The studied specimen features a main axis bearing helically to irregularly arranged bract‐cupule complexes, each composed by a long laminar bract subtending and sheathing a cupule stalk that bears a single‐seeded cupule with a dorsal protrusion. The morphological features of this taxon do not conform with those of Karkenia, and suggest affinities with Doyleales rather than Ginkgoales. Within Doyleales, this fossil has a unique combination of characters indicating that it is a new genus within the order; thus, a new combination is erected, Zirabia cylindrica. Conclusions: Our results indicate that Doyleales is significantly older than previously thought, with their stratigraphic range now extending from the Lower Jurassic to the Cretaceous. The Early Jurassic occurrence of Doyleales provides important data on the emergence of seed‐enclosing structures seen in seed plants throughout the Mesozoic. [ABSTRACT FROM AUTHOR]

This paper deals with the Mesozoic seed ferns from the Shemshak Group from two localities in the Western Alborz Mountains, Northern Iran (i.e., the Abyek area in Qazvin Province and the Jirande area in Gilan Province). The materials were obtained from two coal-bearing horizons in the Shemshak Group, Late Triassic-Middle Jurassic in age. Five species from the Abyek and two species from the Jirande area, belonging to the phylum Pteridospermophyta, were identified. Vegetative and reproductive organs of Caytoniales (i.e., Sagenopteris sp. A and Sagenopteris sp. B leaves, Caytonia sp. ovuliferous organ, and Caytonanthus arberi Thomas (Harris) emend. Harris, 1964 microsporangiate organ, as well as two form-species of incertae sedis seed ferns, Pachypteris lanceolata Brongniart, 1828 and Ptilozamites tenuis Ôishi 1932 emend. Ôishi and Huzioka, 1938) are described in the present paper. This paper discusses the morphological characters of these species, together with discussions on their previous palaeobotanical descriptions, as well as the stratigraphic and palaeogeographical distribution of these taxa. This is the first record of Caytonanthus arberi in Asia and Ptilozamites tenuis from Iran. Pachypteris lanceolata is described for the first time in the Western Alborz. [ABSTRACT FROM AUTHOR]

A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures.

Here we report a pollen organ from the upper Permian of the Dead Sea region with in situ pollen showing a wall structure typical for lyginopterid seed ferns. The single specimen resembles the dispersed seed-fern pollen organs Dictyothalamus and Melissiotheca in being composed of numerous densely positioned, radiating pollen sacs that together form a characteristic honeycomb-like surface pattern. The small, rounded to oval, non-saccate cryptaperturate in situ pollen grains have a verrucate sculpture and show an alveolate wall ultrastructure with alveoli arranged in several tiers. The lyginopterids, a group of seed ferns, first appeared in the latest Devonian and were very widespread across Euramerica during the Mississippian. The group shows a clear demise in the middle and late Pennsylvanian. The youngest representatives have been reported from late Permian peat-swamps in Cathaysia. The morphology of the pollen organ, the ultrastructure of the pollen, and associated foliage present further evidence that lyginopterid seed ferns persisted until the late Permian and demonstrate that they were not restricted to peat-forming swamp environments, but that they were able to survive in drier environments. [ABSTRACT FROM AUTHOR]

A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures. [ABSTRACT FROM AUTHOR]

New discoveries of corystosperm seed-bearing structures from the Tevshiin Govi locality, Mongolia, which is of Early Cretaceous (Aptian–Albian) age, show that the individual seed-bearing units of Umkomasia mongolica were borne in a cone, as also documented for the very similar reproductive units of Doylea tetrahedrasperma. New material from the Tevshiin Govi locality also documents two additional species of Umkomasia – U. corniculata sp. nov. and U. trilobata sp. nov. – that most likely grew in a different environment to U. mongolica. The occurrence of three different Umkomasia species in the Early Cretaceous of Mongolia, together with other records from the Early Cretaceous of the Northern Hemisphere, indicate that previous concepts of corystosperms, based mainly on material from the Southern Hemisphere, need to be revised. The consistent reproductive architecture of the seed-bearing structures in all three corystosperm species, with a bract subtending a variously modified axis bearing ovules, is similar to the situation in Ginkgo and conifers. These underappreciated architectural commonalities among the reproductive structures of major groups of seed plants are likely significant for a deeper understanding of seed plant evolution and require further exploration. [ABSTRACT FROM AUTHOR]

An Upper Pennsylvanian locality (Bonner Springs Shale, Kansas City Group, Middle Missourian) in western Missouri contains a diverse and well-preserved fossil assemblage of both plants and arthropods. The plants are preserved as impressions and compressions, and include fertile and vegetative remains of various sphenopsids, lycopsids, ferns, seed ferns, cordaites and conifers. The discovery of a branching system with lyginopterid pollen organs, Parkvillia northcuttii , demonstrates that this group of Paleozoic seed ferns was more diverse and complex than previously known. The fertile structure is characterized by multiple levels of branching with the penultimate branches alternately arranged; ultimate rachises bearing 6–10 alternately arranged, slightly flattened, shield-shaped synangia. Synangia are approximately 5 mm in diameter and each consists of a cap with up to 18 sporangia attached to the abaxial surface. The radial and trilete pollen is ornamented by grana and coni. Also in the assemblage are small radially symmetrical ovules and sphenopterid foliage, suggesting that this assemblage contains multiple lyginopterid taxa. The orientation of sporangia and features of the synangia, together with the three-dimensional branching, indicate a morphological pattern that has not been recognized within the Lyginopteridaceae. [ABSTRACT FROM AUTHOR]

Corystosperms, a key extinct group of Late Permian to Early Cretaceous plants, are important for understanding seed plant phylogeny, including the evolution of the angiosperm carpel and anatropous bitegmic ovule., Here, we describe a new species of corystosperm seed-bearing organ, Umkomasia mongolica sp. nov., based on hundreds of three-dimensionally preserved mesofossils from the Early Cretaceous of Mongolia., Individual seed-bearing units of U. mongolica consist of a bract subtending an axis that bifurcates, with each fork (cupule stalk) bearing a cupule near the tip. Each cupule is formed by the strongly reflexed cupule stalk and two lateral flaps that partially enclose an erect seed. The seed is borne at, or close to, the tip of the reflexed cupule stalk, with the micropyle oriented towards the stalk base., The corystosperm cupule is generally interpreted as a modified leaf that bears a seed on its abaxial surface. However, U. mongolica suggests that an earlier interpretation, in which the seed is borne directly on an axis (shoot), is equally likely. The 'axial' interpretation suggests a possible relationship of corystosperms to Ginkgo. It also suggests that the cupules of corystosperms may be less distinct from those of Caytonia than has previously been supposed. [ABSTRACT FROM AUTHOR]

Abstract: We describe a distinct type of heteromorphic basal frond element in four species of the seed-fern foliage Dicroidium, based principally on a survey of plant-fossil collections from the Triassic of Antarctica. The modified foliar elements are conspicuously enlarged, and arise at wide angles and obliquely to the frond plane. Those of D. elongatum and D. crassinerve arise more or less directly from the petiole base; they are overall wedge- to fan-shaped with variably dissected margins and fan-shaped venation. Those of D. odontopteroides and D. dubium are (sub)circular, reniform, or obcordate, also with fan-shaped venation, or divided into narrow tongue-shaped segments with alethopteroid venation. The basal elements of some species commonly occur isolated. By analogy with comparable structures among other plant groups, we conclude that the basal elements represent a distinct, early leaf-ontogenetic architectural unit in the frond bauplan of Dicroidium, which provides an important additional character for a more accurate delimitation and systematic classification. Similar structures also occur on the corystosperm reproductive organs Umkomasia and Pteruchus. It appears that the basal elements were particularly common among high-latitude Dicroidium trees that flourished in a strongly seasonal light regime. We hypothesize that the modified elements may represent the initial foliar outgrowths during spring flush, ensuring a rapid re-initiation of sap flow and metabolic activity after the extended period of winter dormancy. [Copyright &y& Elsevier]

Abstract: The Pennsylvanian foliage morphogenus Lobatopteris is commonly referred to the marattialean ferns based on the presence of synangia in fertile specimens. This paper reports on a seed-bearing frond segment from the Westphalian D (Upper Pennsylvanian) of the Zwickau–Oelsnitz Basin, Germany, that corresponds to Lobatopteris with regard to gross morphology and venation. Seeds are ovoid and occur in place of basiscopic pinnules positioned proximally on the ultimate pinnae. Lateral extensions of the seed integument appear to form two wings in a primary plane. Discovery of a seed-bearing lobatopterid reveals that this type of foliage was not exclusively produced by ferns, but also by seed plants. [ABSTRACT FROM AUTHOR]

The recent classification of angiosperms by Chase and Reveal, based on APG III and emphasizing holophyletic concepts, results in a system of 16 coordinate superorders. Some of these contain very little diversity, such as Amborellanae or Ceratophyllanae, and others are extremely rich, such as Lilianae (monocots) or Rosanae. It is argued that the very diverse basal angiosperm group may represent ancient early lines of evolution (early evolutionary experiments) that have come from different seed fern ancestors. A reasonable approach to the classification of this mixed group is to regard them as a paraphyletic class of angiosperms (Archaeangiospermae). This allows the eudicots and monocots to be treated, as often in the past, as class Dicotyledonae and class Monocotyledonae. [ABSTRACT FROM AUTHOR]

A remarkably diverse Lower Cretaceous (Valanginian-Hauterivian) flora at Apple Bay, Vancouver Island, preserves seed plants at an important time of floristic evolutionary transition, about the same time as the earliest flowering plant megafossils. The fossils are permineralized in carbonate concretions and include tetrahedral seeds within cupule- or carpel-like structures. These enclosing structures, composed of elongate sclerenchyma cells with spiral thickenings that grade externally to a few layers of parenchyma, are vascularized by one collateral vascular bundle and lack trichornes. They apparently broke open to release the tightly enclosed seeds by valves. Seeds are similar to those of the Triassic seed fern Petriellaea, but arc about 100 million years younger and differ in size, vascularization, integumentary anatomy, seed attachment, and number of seeds/cupule. These new seeds ale described as Doylea zetrahedraspernia gen. et sp. nov., tentatively assigned to Corystospermales. Inverted cupules are reminiscent of an outer angiosperm integument rather than a carpel. Like fruits, cupules opened to release seeds at maturity, thereby foretelling several aspects of angiospermy. They show that nearly total ovule enclosure, a level of organization approaching angiospermy, was achieved by advanced seed ferns during the Mesozoic. [ABSTRACT FROM AUTHOR]

Abstract: New material of the Early Permian alethopterid genus Macralethopteris is examined in detail. The material stems from different locations and statistical comparison of the morphological differences between collections suggests that the material is derived from several populations of a single species. Comparison is made with related Cathaysian and Euramerican species, showing the isolated occurrence of Macralethopteris in the Cathaysian region. Characteristics of the species and possible ecological implications suggest that Macralethopteris hallei grew in more mesic circumstances than usually associated with alethopterids. It is argued that M. hallei might have been a relatively small alethopterid with possible cormous growth. [Copyright &y& Elsevier]

Seed ferns, dominant elements of the vegetation in many parts of the world from the Triassic to Cretaceous, were considered to have disappeared at the end of the Cretaceous together with several other groups that had occupied key positions in terrestrial and marine ecosystems such as dinosaurs, plesiosaurs, and ammonoids. Seed-fern demise is generally correlated with competition from diversifying flowering plants through the Cretaceous and the global environmental crisis related to the Chicxulub impact event in the paleotropics at the end of the period. New fossils from Tasmania show that one seed-fern lineage survived into the Cenozoic by at least 13 million years. These fossils are described here as a new species, Komlopteris cenozoicus. Komlopteris is a genus of seed ferns attributed to Corystospermaceae and until now was not known from sediments younger than the Early Cretaceous. Discovery of this "Lazarus taxon," together with the presence of a range of other relictual fossil and extant organisms in Tasmania, other southern Gondwanan provinces, and some regions of northern North America and Asia, underscores high-latitude regions as biodiversity refugia during global environmental crises and highlights their importance as sources of postextinction radiations. [ABSTRACT FROM AUTHOR]

Abstract: Interpreting the reproductive biology of fossil plants has contributed significantly to our understanding of plant evolution. Especially important are studies that have focused on structurally preserved reproductive organs that contain pollen or spores. Among Carboniferous pteridosperms, the medullosans are interpreted as a highly diverse group based on a large number of pollen organs and ovules. Here we report a permineralized pollen organ of Pennsylvanian age (Breathitt Formation) from eastern Kentucky, USA. The synangium is slightly more than a centimeter long and approximately 2.5 mm in diameter, and composed of 10–12 thin-walled, elongate sporangia. Vascular bundles occur in the periphery of the ground tissue. Pollen grains are of the Monoletes-type and up to 195 μm long. When compared with other Monoletes-producing pollen organs, the Lewis Creek synangium is most similar to the impression/compression morphotype Aulacotheca. Based on the co-occurrence of vegetative and reproductive organs, we suggest that this pollen organ was borne on Medullosa anglica. [Copyright &y& Elsevier]

Four Dicroidium species and associated fertile organs are here described from the late Permian Umm Irna Formation (Dead Sea Region, Jordan). Dicroidium irnense , D. jordanense and D. robustum , which were so far only known from the Wadi Himara locality, are now reported from several other sites, some yielding nearly complete fronds and excellently preserved cuticles; D. hughesii , a species so far only known from the Triassic, is here reported from the upper Permian. The largest species, D. robustum emend. nov., can be correlated with the pollen organ Pteruchus lepidus sp. nov. and the cupulate structure Umkomasia aequatorialis sp. nov. based on repeated co-occurrences and striking similarities in cuticular features. Dicroidium irnense is associated with Pteruchus frenguellii sp. nov. based on consistent co-occurrence. Dispersed Umkomasia seeds are common in all localities where Dicroidium occurs. The here described material comprises some of the most completely reconstructed species of Umkomasiaceae known to date. All Dicroidium plants are characterized by comparatively large fronds and both Pteruchus species have strongly elongate, strap-shaped microsporophylls, similar to Triassic Umkomasiaceae growing under comparable, seasonally dry conditions. Dicroidium first appeared during the late Permian in the paleotropical regions, survived the end-Permian biotic crisis, colonized large parts of Gondwana during the Triassic, and persisted in southern high-latitude refugia into the Jurassic. Umkomasiaceae thus show a remarkable resilience as the group survived two of the most severe mass extinctions in Earth history. • We present new evidence for late Permian Dicroidium foliage. • A new species of Umkomasia and two new species of Pteruchus are described. • Fertile organs are correlated with co-occurring Dicroidium species. [ABSTRACT FROM AUTHOR]

Reported for the first time is a physical association of complex-structured trichomes with foliar Odontopteris schlotheimii Brongniart, 1831 from the type Manebach Formation, Germany. This is based on examining rock matrices dissolved by hydrofluoric acid of bipinnate and pinnate material. These trichomes and their inferred dense distribution, most significantly, are directly comparable with those of specimens of Odontopteris cantabrica Wagner, 1969 from the Canadian Sydney Coalfield used as index fossil to establish the Cantabrian Substage. This result is one strong argument that invites comparison with O. schlotheimii , in addition to the acknowledged common pinnule morphologies of O. cantabrica and O. schlotheimii. Additionally, trichomes are not observed in samples of the rock matrix of a fragmentary axis associated with Lesquereux' specimen of O. schlotheimii (Southern Anthracite Field, eastern Pennsylvania, USA). Results of the trichomic comparison and taxonomic implication thereof will be discussed in a future paper. Unlabelled Image • Odontopteris schlotheimii Brongniart from the Manebach type locality is studied • First report of physical association of structurally complex trichomes and foliage • Trichomes structural complexity similar to that of Canadian O. cantabrica Wagner • Results invite taxonomic types comparisons: O. cantabrica vs. O. schlotheimii • The axis associated with Lesquereux' O. schlotheimii sample preserved no trichomes [ABSTRACT FROM AUTHOR]