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Terminalia palaeopubescens sp. nov. (Combretaceae) da Formação Fonseca (Eoceno/Oligoceno) de Minas Gerais, Brasil: Morfologia Foliar, Fungos Epifilicos Associados e Paleoclima
Abstract
TERMINALIA PALAEOPUBESCENS NOV. SP. (COMBRETACEAE), FROM THE FONSECA FORMATION (EOCENE/ OLIGOCENE), MINAS GERAIS STATE, BRAZIL: LEAF ARCHITECTURE, EPYPHYLLOUS FUNGI AND PALEOCLIMATE. In this study, well-preserved leaf-blade compressions and impressions from shale levels in the Fonseca Formation (Priabonian/Rupelian of the Fonseca Basin, state of Minas Gerais, southeastern Brazil) and associated epiphyllous fungi are described. Based on leaf architecture and indumentum, a new species is established, assigned to the extant tropical genus Terminalia L. (Combretaceae). The leaf of Terminalia palaeopubescens sp. nov. is mesophyll, narrow obovate and with an entire margin. Its secondary veins are camptodromous-brochidodromous, the tertiary pattern is percurrent mixed predominantly alternate, the quaternaries are alternate percurrent and the higher orders regular polygonal reticulate, with small and well developed areoles. Trichomes are present in the indumentum and are simple, slender, pointed, and with a swollen base, typical of the Combretaceae. Epyphyllous fungi, in the shape of microthyrioid disks of variable size and profusely colonizing the leaf surface, were assigned to Callimothallus Dilcher (Microthyriaceae). The presence of those biogenic structures (besides Phragmothyrites Edwards, already reported in the same levels of the Fonseca Formation) indicates that a prominent leaf mycoflora was associated to the vegetation, probably sustained by warm and humid conditions. The data here presented, analyzed together with other taxonomic, taphonomic and foliar physiognomic indicators, lead to the hypothesis that a dense rainforest, supported by heavy rainfall and high temperatures, was thriving near the banks and floodplain environments associated to fluvial systems of the Fonseca Formation, during the Eocene/Oligocene transition, in southeastern Brazil.
... Jean Carlo Mari Fanton is a biologist from UNICAMP who, between 2004 and 2013, worked with morphology and taxonomy of fossil gymnosperms from the Paraná Basin (Palaeozoic), and angiosperms from the Araripe Basin (Cretaceous) and Fonseca and Gandarela basins (Cenozoic). He is the principal author of some species: Iara iguassu Fanton, Ricardi-Branco, Dilcher et Bernardes-de-Oliveira, and Terminalia palaeopubescens Fanton et Ricardi-Branco (Fanton et al. 2006;Fanton and Ricardi-Branco 2012). ...
... Some exceptions are the macrofossil records from the late Eocene Fonseca Formation (Brazil), the Bucaro Formation (Panama), and the Huambos Formation (Peru). These floras include fossils of plant families that are now characteristic of the tropics (Berry, 1935;Duarte, 1958;Fanton et al., 2012;Herrera et al., 2012;de Lima and Salard-Cheboldaeff, 1981;Mello et al., 2000;Woodcock et al., 2017). In addition, Eocene and Oligocene macrofossils from the La Carroza and the Coatzingo formations provide evidence of the Tertiary diversification of Fabaceae in central Mexico (Calvillo-Canadell and Cevallos-Ferriz, 2005;Pérez-Lara et al., 2019;Pérez-Lara et al., 2017). ...
Movement toward our current climate state began in the middle Eocene to early Oligocene interval when the global temperature cooled and the first Antarctic ice sheet appeared. This dramatic climate change caused a significant global turnover in both marine and terrestrial biotas. The biotic response to this event at low latitudes remains mostly unexplored. Here, we studied a recently discovered Eocene fossil macro- and palynoflora from Esmeraldas Formation (Colombia). The Esmeraldas Flora consists of more than seven hundred macrofossil specimens found in two localities, including 15 morphotypes of leaves, seeds, cuticles, fruits, and flowers and > 5000 palynomorphs, that include 210 morphospecies. The Esmeraldas Formation is dominated by meandering river floodplain deposition, and was dated, using palynology and isotopic stratigraphy, as middle to late Eocene (~47.3 to ~33.9 Ma). Quantitative paleoclimatic calculations based on leaf physiognomy and coexistence analyses indicate a warm temperature and a seasonal precipitation within the range of modern tropical dry forests. Furthermore, the floristic composition that includes the presence of macrofossils of the Pterocarpus clade (Fabaceae), and pollen records of the subfamily Bombacoideae (Malvaceae), and Euphorbiaceae, could be indicative of a tropical dry forest. The overall paleobotanical record suggests that the Esmeraldas flora represents one of the earliest records of a tropical dry forest from low latitudes.
... Palaeogeographical range of N. pertusus covers nearly all the continents. It was reported from Europe (Pound et al., 2012;Worobiec and Worobiec, 2017), Asia (Saxena and Tripathi, 2011;Singh et al., 2015), North America (Kalgutkar, 1997), South America (Fanton et al., 2012;Premaor et al., 2018), Africa (Venkatachala et al., 1998, as Phragmothyrites eocenicus;Cole et al., 2017), and Australia (Owen, 1988;Carpenter et al., 2004). It is absent, however, from the Neogene and younger deposits of the Arctic and Antarctic regions. ...
This paper presents the reinterpretation of the taxonomic position of fossil epiphyllous callimothalloid fungi belonging to the fossil-genera Callimothallus (hitherto classified to the family Microthyriaceae) and Cribrites (?Microthyriales). These fungi thrived from the Late Cretaceous up to the Holocene. Investigation are based on collected material from the Oligocene of Hungary and the Miocene of Poland and on published data. For the common callimothalloid fungus Callimothallus pertusus, a new combination Neomycoleptodiscus pertusus is proposed. Callimothallus quilonensis is assigned to a new fossil-genus Muyocopromyces as a new combination Muyocopromyces quilonensis. We reconsider the fossil-species Ratnagiriathyrites hexagonalis as a younger synonym of the fossil-genus Cribrites. The geographical range of fossil callimothalloid fungi and their recent counterparts are discussed. Fossil Neomycoleptodiscus Hern.-Restr., J.D.P. Bezerra & Crous, Muyocopromyces, and Cribrites are proposed as reliable climate proxy of warm climate conditions in the past.
... Fossil records suggest that the distribution of South American forests was quite ample during the Eocene and the Miocene, and such a result was corroborated by climate simulations (Bush and Flenley, 2007;Fanton et al., 2012;Micheels et al., 2007). Since mid-Miocene, global orogenic events -including the Andean uplift -have altered the dynamics of heat circulation and rain on Earth, leading to effects such as a reduction in temperature and an increase in climatic seasonality (Armijo et al., 2015;Micheels et al., 2011;Potter and Szatmari, 2009). ...
The area occupied by tropical forests in South America has continually experienced shrinkage since the Miocene, with the formation of the Dry Diagonal, which is composed of seasonally dry tropical forests and savannas (Caatinga, Cerrado, and Chaco). Here, we contribute to the understanding of the establishment of the Dry Diagonal by testing the hypotheses of “ancestral fragmentation” and of “colonization” to explain the current distribution of species in rocky humid formations of Cerrado, a Neotropical savanna in Brazil. Populations of Mandirola hirsuta (Gesneriaceae) were sampled in 25 localities; these cover the species’ entire geographical distribution, and the plastid intergenic regions psbA-trnH and trnQ-5′-rps16 were sequenced. The findings show that intrapopulation genetic variability was low, whereas interpopulation variability was high. We detected seven genetic groups that were geographically well delimited, and no signs of recent population expansion were observed. Divergence between the seven main lineages took place between the late Miocene and the Pliocene periods. In Approximate Bayesian Computation, the fragmentation scenario had a significantly higher probability than the colonization scenario. Results support the hypothesis of a former broader distribution for the humid vegetation, which was fragmented with the expansion of savannas; results also indicate population differentiation promoted by a rapid expansion of the Dry Diagonal.
... Some exceptions are the macrofossil records from the late Eocene Fonseca Formation (Brazil), the Bucaro Formation (Panama), and the Huambos Formation (Peru). These floras include fossils of plant families that are now characteristic of the tropics (Berry, 1935;Duarte, 1958;Fanton et al., 2012;Herrera et al., 2012;de Lima and Salard-Cheboldaeff, 1981;Mello et al., 2000;Woodcock et al., 2017). In addition, Eocene and Oligocene macrofossils from the La Carroza and the Coatzingo formations provide evidence of the Tertiary diversification of Fabaceae in central Mexico (Calvillo-Canadell and Cevallos-Ferriz, 2005;Pérez-Lara et al., 2019;Pérez-Lara et al., 2017). ...
Inaccurate taxonomic placement of fossils can lead to the accumulation of errors in molecular clock studies and their generated evolutionary lineages. There are limited fossil data that can be used in divergence time estimations. Therefore, reliable morphological characterization and taxonomical identification of fossil fungi are extremely important. Most fossils of Dothideomycetes and Sordariomycetes are from the early Cenozoic (66–23 Mya), with fewer from the late Mesozoic (174–145 Mya). However, it is hard to distinguish some fossil descriptions as photographs and illustrations are unclear; thus, the validity of using these fossils in calibrations of molecular clocks is problematic. This study brings scattered paleobiological data on selected fossil Ascomycota, using descriptions, fossil images and illustrations, coupled with recent age estimations, and taxonomic and phylogenetic affinity of extant species. As an integrated approach, this study summarizes a historical fossil outline with a reliable minimum age for 16 calibrating points viz. crown of Aigialus, Anzia, Aspergillus, Asterina, Calicium chlorosporum–C. nobile, Capnodiales, Chaenotheca, Colletotrichum, Diaporthales, Meliola, Ophiocordyceps, Microthyriales, Microthyrium, Muyocopron, Pezizomycotina and Stigmatomyces. A scheme of Ascomycota ancient lineages is also provided in order to improve divergence time estimations.
RESUMO As variações da composição da flora arbórea de 60 áreas de floresta atlântica sensu lato (ombrófilas e semidecíduas) da região das Bacias do Leste, englobando o sul da Bahia, o Espírito Santo, o leste de Minas Gerais e o norte do Rio de Janeiro, são analisadas em articulação com variáveis geográficas e climáticas. Listagens de espécies são fornecidas para 16 destas áreas. Análises multivariadas detectaram três padrões de distribuição. (a) A diferenciação entre florestas ombrófilase semidecíduas na regiãoé floristicamente consistente efortemente correlacionada com a sazonalidade do regime de chuvas. A flora arbórea das florestas semidecíduas é, em boa medida, um subconjunto da flora das florestas ombrófilas, extraindo espécies provavelmente mais eficientes em resistir e competir sob condições de seca mais prolongada. (b) Existe uma diferenciação latitudinal tanto para florestas ombrófilas e semidecíduas, que aproxima floristicamente as duas fisionomias dentro da mesma faixa latitudinal. Este padrão é causado provavelmente por variações térmicas e pluviométricas. As florestas ombrófilas são interrompidas no norte fluminense devido ao clima estacional, mas isto não tem como contrapartida uma disjunção na distribuição de espécies arbóreas. (c) As variações da altitude estão fortemente correlacionadas com a diferenciação interna tanto das florestas ombrófilas como das semidecíduas.
The tree flora of southeastern Brazilian Atlantic forests was investigated according to two main aspects: (a) the variations in floristic composition of both rain and semi-deciduous forests were analyzed in terms of geographic and climatic variables by performing multivariate analyses on 125 existing floristic checklists; and (b) the links of both rain and semi-deciduous forests to Amazonian forests and Cerrados (woody savanna) were assessed. All analyses were performed at the species, genus, and family levels. The information obtained for the 125 forest areas was organized into an environmental database containing geographic and climatic records, and a floristic database containing binary presence records for 2532 species, 520 genera, and 106 families. Canonical correspondence analyses (CCA) were utilized to assess the relationship between geographic and climatic variables, and tree flora composition. Venn diagrams and cluster analyses were used to assess the floristic links to Amazonian forests and Cerrados. The following patterns were detected at all three taxonomic levels: (a) the differentiation between rain and semi-deciduous forests is floristically consistent and strongly correlated with rainfall regime, although transitions may be abrupt to gradual; (b) a north-south differentiation exists for both rain and semi-deciduous forests, probably caused by variations in both temperature and rainfall regime; (c) The flora of semi-deciduous forests also changes with increasing distance from the ocean and the associated increasing rainfall seasonality; and (d) elevation and associated temperatures are strongly correlated with the internal differentiation of both rain and semi-deciduous forests. To a considerable extent, the tree flora of semi-deciduous forests is a subset of the rain forest flora, probably extracting species that are able to cope with a longer dry season. There is greater floristic similarity at the species level between Atlantic rain and semi-deciduous forests than between any of these and either Amazonian rain forests or Cerrados. Nevertheless, semi-deciduous forests and Cerrados show stronger links, particularly at the generic and familial levels. Therefore, there is little floristic ground for viewing Atlantic rain forests as being closer to their Amazonian counterparts than to the adjacent semi-deciduous forests. The most appropriate view of rain and semi-deciduous forests in southeastern Brazil is that of a continuum in tree species distribution. We suggest that the definition of Atlantic forests should be as comprehensive as that of Amazonian forests.
Fungal fruitbodies occurring on or in fossil leaves from a Miocene lake bed near Clarkia, Idaho, are documented and their ecological implications discussed. The epiphyllous mycoflora is limited to hyphopodiate mycelium and a plurivorous species of hemisphaerialean thyrothecium. Immersed fruitbodies occur on most of the leaves examined. A diversity of host-specific forms are represented. None contain spores, suggesting either that the fruitbodies are immature or that the spores that they contained were hyaline and thin-walled, and thus unlikely to survive fossilization and extraction. These observations are consistent with a temperate, predominantly deciduous flora with early colonization of senescent leaves by pycnidial fungi.
Age and size structures, and tree locations were used to identify cohorts of trees that were initiated by flood events. This, along with information on species microsite preferences and spatial patterning, was used to reconstruct the patterns of establishment of the four dominant canopy trees (Dacrycardpus dacrydioides, Dacrydium cupressinum, Prumnopitys ferruginea, Weinmannia racemosa) in response to flood disturbance. The four species coexisted by partitioning establishment site with respect to the amount of overhead cover and the type of forest floor microsite. D. dacrydioides and D. cupressinum established in large gaps but colonized contrasting microsites; D. dacrydioides established mostly on mineral soil while D. cupressinum established on elevated microsites. W. racemosa and P. ferruginea both established on elevated microsites beneath largely intact canopies. However, W. racemosa colonized canopy gaps while P. ferruginea established mostly under closed cover. Disturbance was critical to the maintenance of species diversity because it was the source of much of the environmental variation to which species responded differentially. -from Author
The seven species described in the genus Thiloa are reduced to three. These three species are distinct on morphological, anatomical and distributional criteria, and any difficulties in identification are apparently due to poor or incomplete material and the minute nature of the most diagnostic characters, since no real taxonomic problems have been found. The study was based on the material in 25 major herbaria, including the type specimens of all taxa.