Angiosperms diverse in Late Cretaceous fossil forest in New Mexico + cockroaches document Mesozoic polar ‘hothouse’ canopy jungles
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Ben Creisler
Jun 25, 2026, 3:31:52 PM (24 hours ago) Jun 25
to DinosaurMa...@googlegroups.com
Ben Creisler
Highlights
Deciduous forest originated within polar circles in response to bivalent conditions.
High-intensity fires indicate tall tree canopies extending through to the North pole.
Extinct ecosystems with tropical insects suggest polar day microclimate warm.
‘Dark’ or ‘Black-and-White biota’ formed temperature edge of global warming.
Global warming harmless when we stop deforestation.
Forest constituents in Cretaceous high latitudes dominated by relictual Jurassic taxa.
Abstract
Mesozoic high-latitude forests developed within polar circles are poorly known, as are the ecosystems that formed within them. Cockroaches and praying mantises from palaeo-polar deposits in Victoria: Koonwarra (Australia, southern hemisphere), Yakutia, Taimyr, Khabarovsk, Magadan, and Chukotka (Russia, northern hemisphere) occur within taphonomically diverse sedimentary, ‘coal’ and amber deposits. Along with high-latitude deposits in Alaska, Canada, New Zealand, southeastern Australia and Antarctica, these assemblages were affected by light polarities. The polar assemblages considered here include both nocturnal and diurnal insects with unusual features such as dark coloration, specific wing shapes, metallic cuticle, and two main reflective and three additional simple eyes. Many taxa show relictual characteristics, although hypermodern lineages occurred. By combining paleobiology, sedimentology/physics and organic petrography/chemistry, our research suggests that high-latitude Cretaceous organisms in the northern hemisphere exploited tropical microclimates with permanent summer insolation, whereas southern polar hothouse forests were more temperate. We name this unusual assemblage lacking colorful cockroaches the ‘Dark Biota’, which developed during Earth’s global warming maximum (up to 24.3°C) in the Barremian–Aptian. We interpret it as inhabiting multi-level forests comprised of canopy conifers and small-leaf angiosperms strongly influenced by megafires. Deciduous forests likely originated in these regions in response to the unusual light conditions.
Recent Mesozoic papers:
Fossils upend catastrophist narrative that flowering plants flourished only after dinosaur extinction
‘Botanical Pompeii’ shows angiosperms prospered 10 million years before dinosaur demise
https://www.eurekalert.org/news-releases/1132648
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Jaemin Lee, Dori L. Contreras, James G. Saulsbury, Garland R. Upchurch, and Cindy V. Looy (2026)
Diversification of angiosperm reproductive strategies predated the end-Cretaceous extinction
Science 392(6805): 1380-1383
DOI: 10.1126/science.adw9457
https://www.science.org/doi/10.1126/science.adw9457
Editor’s summary
Flowering plants have remarkable diversity in fruit and seed size and shape, reflecting morphology for dispersal by wind, water, and animals. This diversity is thought to have only originated during the Paleogene despite an earlier increase in abundance and diversification of angiosperms across the Cretaceous. Lee et al. now suggest an earlier origin of variation in angiosperm diaspores (seeds and fruits). They describe a relatively well-preserved collection of 77 diaspore morphotypes from a Late Cretaceous fossil forest in New Mexico featuring fleshy fruits with an average weight approximately the size of a blueberry. Although likely dispersed by vertebrates, the emergence of these morphotypes may have been part of the shift to shady, humid tropical forests rather than being driven by vertebrate diversification. —Bianca Lopez
Abstract
Angiosperm reproductive evolution is traditionally linked to the end-Cretaceous biotic crisis and subsequent ecological restructuring. Here, we report diverse and unexpectedly large diaspores (dispersal units) from an in situ late Campanian (74.6 million years ago) tropical forest from the Jose Creek Formation in New Mexico. Nearly 80 distinct diaspore morphotypes demonstrate that the flora had increased morphological specialization and an exceptionally large average and range of diaspore volume comparable to the Cenozoic records. These findings suggest that substantial increases in reproductive investment and specialization preceded the end-Cretaceous extinction. Our results indicate that Cretaceous angiosperms had already evolved diverse dispersal strategies, suggesting that animal-mediated dispersal and dense, angiosperm-integrated canopies were established far earlier than was previously recognized.
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News:
Diversification of angiosperm reproductive strategies predated the end-Cretaceous extinction
Science 392(6805): 1380-1383
DOI: 10.1126/science.adw9457
https://www.science.org/doi/10.1126/science.adw9457
Editor’s summary
Flowering plants have remarkable diversity in fruit and seed size and shape, reflecting morphology for dispersal by wind, water, and animals. This diversity is thought to have only originated during the Paleogene despite an earlier increase in abundance and diversification of angiosperms across the Cretaceous. Lee et al. now suggest an earlier origin of variation in angiosperm diaspores (seeds and fruits). They describe a relatively well-preserved collection of 77 diaspore morphotypes from a Late Cretaceous fossil forest in New Mexico featuring fleshy fruits with an average weight approximately the size of a blueberry. Although likely dispersed by vertebrates, the emergence of these morphotypes may have been part of the shift to shady, humid tropical forests rather than being driven by vertebrate diversification. —Bianca Lopez
Abstract
Angiosperm reproductive evolution is traditionally linked to the end-Cretaceous biotic crisis and subsequent ecological restructuring. Here, we report diverse and unexpectedly large diaspores (dispersal units) from an in situ late Campanian (74.6 million years ago) tropical forest from the Jose Creek Formation in New Mexico. Nearly 80 distinct diaspore morphotypes demonstrate that the flora had increased morphological specialization and an exceptionally large average and range of diaspore volume comparable to the Cenozoic records. These findings suggest that substantial increases in reproductive investment and specialization preceded the end-Cretaceous extinction. Our results indicate that Cretaceous angiosperms had already evolved diverse dispersal strategies, suggesting that animal-mediated dispersal and dense, angiosperm-integrated canopies were established far earlier than was previously recognized.
****
News:
Fossils upend catastrophist narrative that flowering plants flourished only after dinosaur extinction
‘Botanical Pompeii’ shows angiosperms prospered 10 million years before dinosaur demise
https://www.eurekalert.org/news-releases/1132648
=====
Peter V.V. Vršanský, Zuzana Kováčová, Júlia Kotulová, Dmitrij V. Vasilenko, Rastislav Milovský, Stanka Milovská, Dušan Starek, Adrián Biroň, Ľubica Puškelová, Marián Golej, Štefan Nagy, Daniel Kosnáč, Andrej Čerňanský, Martin Česánek, Ľubomír Vidlička, Jan Hinkelman, Matúš Kúdela, Tatiana Kúdelová & Helena Palková (2026)
Cockroaches document paradoxical, relictual Mesozoic polar ‘hothouse’ canopy jungles
Gondwana Research (advance online publication)
doi: https://doi.org/10.1016/j.gr.2026.05.016
https://www.sciencedirect.com/science/article/abs/pii/S1342937X2600167X
Cockroaches document paradoxical, relictual Mesozoic polar ‘hothouse’ canopy jungles
Gondwana Research (advance online publication)
doi: https://doi.org/10.1016/j.gr.2026.05.016
https://www.sciencedirect.com/science/article/abs/pii/S1342937X2600167X
Highlights
Deciduous forest originated within polar circles in response to bivalent conditions.
High-intensity fires indicate tall tree canopies extending through to the North pole.
Extinct ecosystems with tropical insects suggest polar day microclimate warm.
‘Dark’ or ‘Black-and-White biota’ formed temperature edge of global warming.
Global warming harmless when we stop deforestation.
Forest constituents in Cretaceous high latitudes dominated by relictual Jurassic taxa.
Abstract
Mesozoic high-latitude forests developed within polar circles are poorly known, as are the ecosystems that formed within them. Cockroaches and praying mantises from palaeo-polar deposits in Victoria: Koonwarra (Australia, southern hemisphere), Yakutia, Taimyr, Khabarovsk, Magadan, and Chukotka (Russia, northern hemisphere) occur within taphonomically diverse sedimentary, ‘coal’ and amber deposits. Along with high-latitude deposits in Alaska, Canada, New Zealand, southeastern Australia and Antarctica, these assemblages were affected by light polarities. The polar assemblages considered here include both nocturnal and diurnal insects with unusual features such as dark coloration, specific wing shapes, metallic cuticle, and two main reflective and three additional simple eyes. Many taxa show relictual characteristics, although hypermodern lineages occurred. By combining paleobiology, sedimentology/physics and organic petrography/chemistry, our research suggests that high-latitude Cretaceous organisms in the northern hemisphere exploited tropical microclimates with permanent summer insolation, whereas southern polar hothouse forests were more temperate. We name this unusual assemblage lacking colorful cockroaches the ‘Dark Biota’, which developed during Earth’s global warming maximum (up to 24.3°C) in the Barremian–Aptian. We interpret it as inhabiting multi-level forests comprised of canopy conifers and small-leaf angiosperms strongly influenced by megafires. Deciduous forests likely originated in these regions in response to the unusual light conditions.
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