Leyla J. Seyfullah

Estimating the Phanerozoic history of the Ascomycota lineages: Combining fossil and molecular data

The phylum Ascomycota is by far the largest group in the fungal kingdom. Ecologically important mutualistic associations such as mycorrhizae and lichens have evolved in this group, which are regarded as key innovations that supported the evolution of land plants. Only a few attempts have been made to date the origin of Ascomycota lineages by using molecular clock methods, which is primarily due to the lack of satisfactory fossil calibration data. For this reason we have evaluated all of the oldest available ascomycete fossils from amber (Albian to Miocene) and chert (Devonian and Maastrichtian). The fossils represent five major ascomycete classes (Coniocybomycetes, Dothideomycetes, Eurotiomycetes, Laboulbeniomycetes, and Lecanoromycetes). We have assembled a multi-gene data set (18SrDNA, 28SrDNA, RPB1 and RPB2) from a total of 145 taxa representing most groups of the Ascomycota and utilized fossil calibration points solely from within the ascomycetes to estimate divergence times of Ascomycota lineages with a Bayesian approach. Our results suggest an initial diversification of the Pezizomycotina in the Ordovician, followed by repeated splits of lineages throughout the Phanerozoic, and indicate that this continuous diversification was unaffected by mass extinctions. We suggest that the ecological diversity within each lineage ensured that at least some taxa of each group were able to survive global crises and rapidly recovered.

The anatomically preserved stem Zhongmingella gen. nov. from the Upper Permian of China: evaluating the early evolution and phylogeny of the Osmundales

Reinvestigation of the anatomically preserved stem Palaeosmunda plenasioides from the Lopingian (Late Permian) of China has led to the establishment of Zhongmingella gen. nov. within the extinct family Guaireaceae (Osmundales). Zhongmingella has a rhizomatous stem with heterogeneous pith and cortex comprising parenchyma and uniformly distributed secretory cells, and is dictyostelic. In order to evaluate the systematic and phylogenetic position of Zhongmingella within Guaireaceae, and Guaireaceae within Osmundales, we conducted a preliminary cladistic analysis of a broad range of Osmundales and related taxa based on 18 extinct and six extant genera and subgenera. Results do not support the traditionally defined family Thamnopteroideae (Bathypteris, Chasmatopteris, Iegosigopteris, Thamnopteris, Zalesskya) and demonstrate that Thamnopteroideae is not a subfamily of Osmundaceae as previously thought. Guaireaceae is monophyletic but in addition to its traditionally defined members (Guairea, Lunea, Donwellicaulis, Itopsidema, Shuichengella, Zhongmingella) includes the stratigraphically younger genus Osmundacaulis previously placed in Osmundaceae. Guaireaceae is sister to Osmundaceae, Millerocaulis, Ashicaulis, Palaeosmunda and Aurealcaulis in the strict consensus, but in the majority-rule consensus Palaeosmunda, Aurealcaulis, Ashicaulis and Millerocaulis form the Osmundaceae stem group, with (Aurealcaulis, (Ashicaulis + Palaeosmunda)) sister to the extant genera. Stratigraphical analysis of the selected most parsimonious tree demonstrates that Osmundales underwent primary radiation during the Pennsylvanian and Permian, terminating abruptly around the time of the end-Permian mass extinction. Radiation within Osmundaceae occurred in the Triassic–Cretaceous and stratigraphically overlaps staggered extinctions in Guaireaceae and Osmundaceae from the Late Jurassic to mid-Cretaceous alongside the earliest angiosperm radiation. Our results identify the Osmundaceae stem and sister groups for the first time, and represent an important step in unravelling the evolutionary history of Osmundales. However, reconstructed whole-plant species are imperative to improve understanding of the relationships within the clade in deep time.

Anatomically Preserved Pteridosperm Stems and Rachises from Permian Floras of China

Pteridosperms are common in the Permian floras of China and are known from both vegetative and fertile organs in adpression assemblages and as dispersed ovules and seeds in permineralized assemblages. In contrast, reports of vegetative organs from permineralized assemblages are limited, and in all cases, accounts have not been verified by detailed descriptions nor illustration. Here we report four taxa of pteridosperm stem or rachis from the Permian permineralized floras of China. Coal balls from the Asselian‐Sakmarian (Cisuralian) Taiyuan Formation are shown to contain specimens of a medullosan and a lyginopterid pteridosperm. The medullosan rachis has a distinctive collateral organization of vascular bundles interspersed within a crushed parenchymatous ground tissue that also has scattered resin ducts, and it is identified as Myeloxylon Brongniart. The lyginopterid has a vitalized protostelic stem with manoxylic secondary xylem and mesarch xylem maturation and is confirmed as Heterangium sp. 1. From volcaniclastic tuffs from the Wujiapingian‐Changhsingian (Lopingian) Xuanwei Formation, a eustelic stem with a parenchymatous pith surrounded by discrete primary xylem strands with a large amount of secondary xylem and a sparganum‐type cortex is attributed to the Callistophytalean Callistophyton Delevoryas and Morgan. Finally, from the Changhsingian (Lopingian) Wangjiazhai Formation, another lyginopterid is documented that comprises a pair of protostelic stems with manoxylic secondary xylem and mesarch xylem maturation and is assigned to Heterangium sp. 2. Although accounts are based on low specimen numbers, they provide unequivocal evidence of vegetative pteridosperm genera in the Permian of China that were previously known only from the Pennsylvanian and earliest Permian of Euramerica. In this context, they underline the floristic continuation of wetland plant communities extending from the Carboniferous of Euramerica into the Cisuralian‐aged peat‐forming mires in North China and the Lopingian of South China. Extending the geographical and stratigraphical ranges of these pteridosperm taxa means that each should now be considered as potentially important to seed plant evolution and phylogeny during the Permian as well as the Carboniferous.

Carnivorous leaves from Baltic amber

Significance Amber, fossil tree resin, preserves organisms in microscopic fidelity, and frequently fossils preserved in amber are otherwise absent in the entire fossil record. Plant remains, however, are rarely entrapped in amber, compared with the vast amount of insects and other animals. Our newly discovered fossils from Eocene Baltic amber are the only documented case of fossilized carnivorous plant traps and represent the first fossil evidence of the carnivorous plant family Roridulaceae, which is today a narrow endemic of South Africa. Hence, our results shed light onto the paleobiogeography of the Roridulaceae, indicating a wide Eocene distribution of the roridulid ancestors and challenging previous notions about a Gondwanan origin of this plant family. The fossil record of carnivorous plants is very scarce and macrofossil evidence has been restricted to seeds of the extant aquatic genus Aldrovanda of the Droseraceae family. No case of carnivorous plant traps has so far been reported from the fossil record. Here, we present two angiosperm leaves enclosed in a piece of Eocene Baltic amber that share relevant morphological features with extant Roridulaceae, a carnivorous plant family that is today endemic to the Cape flora of South Africa. Modern Roridula species are unique among carnivorous plants as they digest prey in a complex mutualistic association in which the prey-derived nutrient uptake depends on heteropteran insects. As in extant Roridula, the fossil leaves possess two types of plant trichomes, including unicellular hairs and five size classes of multicellular stalked glands (or tentacles) with an apical pore. The apices of the narrow and perfectly tapered fossil leaves end in a single tentacle, as in both modern Roridula species. The glandular hairs of the fossils are restricted to the leaf margins and to the abaxial lamina, as in extant Roridula gorgonias. Our discovery supports current molecular age estimates for Roridulaceae and suggests a wide Eocene distribution of roridulid plants.

Species-level determination of closely related araucarian resins using FTIR spectroscopy and its implications for the provenance of New Zealand amber

Some higher plants, both angiosperms and gymnosperms, can produce resins and some of these resins can polymerize and fossilize to form ambers. Various physical and chemical techniques have been used to identify and profile different plant resins and have then been applied to fossilized resins (ambers), to try to detect their parent plant affinities and understand the process of polymerization, with varying levels of success. Here we focus on resins produced from today’s most resinous conifer family, the Araucariaceae, which are thought to be the parent plants of some of the Southern Hemisphere’s fossil resin deposits. Fourier transform infrared (FTIR) spectra of the resins of closely related Araucariaceae species were examined to test whether they could be distinguished at genus and species level and whether the results could then be used to infer the parent plant of a New Zealand amber. The resin FTIR spectra are distinguishable from each other, and the three Araucaria species sampled produced similar FTIR spectra, to which Wollemia resin is most similar. Interspecific variability of the FTIR spectra is greatest in the three Agathis species tested. The New Zealand amber sample is similar in key shared features with the resin samples, but it does differ from the extant resin samples in key distinguishing features, nonetheless it is most similar to the resin of Agathis australis in this dataset. However on comparison with previously published FTIR spectra of similar aged amber and older (Eocene) resinites both found in coals from New Zealand and fresh Agathis australis resin, our amber has some features that imply a relatively immature resin, which was not expected from an amber of the Miocene age.

The anamorphic genus Monotosporella (Ascomycota) from Eocene amber and from modern Agathis resin.

The anamorphic fungal genus Monotosporella (Ascomycota, Sordariomycetes) has been reco-vered from a piece of Early Eocene Indian amber, as well as from the surface of extant resin flows in New Caledonia. The fossil fungus was obtained from the Tarkeshwar Lignite Mine of Gujarat State, western India, and was part of the biota of an early tropical angiosperm rainforest. The amber inclusion represents the second fossil record of Sordariomycetes, as well as the first fossil of its particular order (either Savoryellales or Chaetosphaeriales). The fossil fungus is distinguished from extant representatives by possessing both short conidiophores and small two-septate pyriform conidia, and is described as Monotosporella doerfeltii sp. nov. Inside the amber, the anamorph is attached to its substrate, which is likely the degraded thallus of a cladoniform lichen. The extant New Caledonian species is assigned to Monotosporella setosa. It was found growing on semi-solidified resin flows of Agathis ovata (Araucariaceae), and is the first record of Monotosporella from modern resin substrates.

Stigmaria Brongniart: a new specimen from Duckmantian (Lower Pennsylvanian) Brymbo (Wrexham, North Wales) together with a review of known casts and how they were preserved

Stigmaria is one of the iconic plant fossils of the Carboniferous and fragments of the narrower parts of the rhizomorph are found in most museum collections. However, very few almost entire specimens have been found and preserved. A new specimen of Stigmaria from Brymbo, North Wales is described and compared with other preserved examples from Europe and North America. The Brymbo specimen shows a large portion of trunk still attached to the large stigmarian base, which is a rare find, and this specimen supports our ideas of how these impressively large casts were formed. Stigmarias were preserved by the deposition of minerals around them following a sediment inundation, which gave sufficient support while the tissues rotted and filled with sediments. Remnants of the outer tissues were compressed to form a thin surrounding coal layer.

Resinogalea humboldtensis gen. et sp. nov., a New Resinicolous Fungus from New Caledonia, Placed in Bruceomycetaceae fam. nova (Ascomycota)

A novel species of ascomycetes is described from resin of Araucaria humboldtensis on Mont Humboldt in New Caledonia. The fungus is placed in the new genus Resinogalea Rikkinen & A.R. Schmidt, with the species name R. humboldtensis Rikkinen & A.R. Schmidt. It has only been found growing on semi-hardened resin flows on branches of its endemic and endangered conifer host. The morphology and anatomy of the new fungus are compared with those of ecologically similar taxa, including Bruceomyces castoris. The new family Bruceomycetaceae Rikkinen & A.R. Schmidt is described to accommodate Resinogalea and Bruceomyces.

Resin exudation and resinicolous communities on Araucaria humboldtensis in New Caledonia

Conifers of the endemic species Araucaria humboldtensis on Mont Humboldt in New Caledonia exhibit extensive resin exudation. The resin flows of these threatened trees are here shown to be induced by two beetle species, which bore into branches and branchlets, leading to abundant outpouring of resin, which gradually solidifies into often drop-shaped resin bodies. The exudate is colonized by a resinicolous and likely insect-vectored ascomycete, Resinogalea humboldtensis, which is only known from Mont Humboldt. The fungus grows into fresh resin and eventually develops ascomata on the surface of solidifying resin. The solidified resin is also colonized by another fungus, a dematiaceous hyphomycete. Based on protein coding (CO1, CAD, ArgK) and ribosomal (LSU) genes, the larger branch-boring beetle is a weevil of the tribe Araucariini, which represents the sister group of all other cossonine weevils. The smaller beetle species belongs to the longhorn beetles (Cerambycidae). The strong host specificity of the Araucariini, along with the occurrence of two unique fungi, suggests that the resin-associated community is native and has evolved on the endemic conifer host. The formation of large amber deposits indicates massive resin production in the past, but the environmental triggers of exudation in Mesozoic and Cenozoic ecosystems remain unclear. Our observations from Mont Humboldt support the notion that the occurrences of small drop-shaped amber pieces in Triassic to Miocene amber deposits were linked to ancient insect infestations.

Production and preservation of resins - past and present.

Amber is fossilised plant resin. It can be used to provide insights into the terrestrial conditions at the time the original resin was exuded. Amber research thus can inform many aspects of palaeontology, from the recovery and description of enclosed fossil organisms (biological inclusions) to attempts at reconstruction of past climates and environments. Here we focus on the resin itself, the conditions under which it may have been exuded, and its potential path to fossilisation, rather than on enclosed fossils. It is noteworthy that not all plants produce resin, and that not all resins can (nor do) become amber. Given the recent upsurge in the number of amber deposits described, it is time to re‐examine ambers from a botanical perspective. Here we summarise the state of knowledge about resin production in modern ecosystems, and review the biological and ecological aspects of resin production in plants. We also present new observations on conifer‐derived resin exudation, with a particular focus on araucarian conifer trees. We suggest that besides disease, insect attacks and traumatic wounding from fires and storms, other factors such as tree architecture and local soil conditions are significant in creating and preserving resin outpourings. We also examine the transformation of resin into amber (maturation), focusing on geological aspects of amber deposit formation and preservation. We present new evidence that expands previous understanding of amber deposit formation. Specific geological conditions such as anoxic burial are essential in the creation of amber from resin deposits. We show that in the past, the production of large amounts of resin could have been linked to global climate changes and environmental disruption. We then highlight where the gaps in our knowledge still remain and potential future research directions.