JM - recent articles

Palynofacies and lacustrine sequence stratigraphy: a case example from the Jurassic Cañadón Asfalto Formation, Cañadón Asfalto Basin, Extra-Andean Patagonia, Argentina

Wed, 13 May 2026 07:32:13 +0200

Palynofacies and lacustrine sequence stratigraphy: a case example from the Jurassic Cañadón Asfalto Formation, Cañadón Asfalto Basin, Extra-Andean Patagonia, Argentina
Daniela Elizabeth Olivera, Carlos Zavala, Mirta Elena Quattrocchio, María Eugenia Soreda, Roberto Scasso, and Renchao Yang
J. Micropalaeontol., 45, 335–357, https://doi.org/10.5194/jm-45-335-2026, 2026
This study explores how climate-driven changes in water balance affected an ancient lake during the Jurassic in Patagonia, and influenced how plant and algal material were deposited and preserved. By combining field observations with palynological analysis, we identified shifts between wetter and drier periods. These shifts controlled lake size, water conditions, and the type and amount of organic matter preserved, improving our understanding of how ancient lake systems record environmental change.

Can the distribution of foraminifera locate the Early Eocene Climatic Optimum (EECO) and Middle Eocene Climatic Optimum (MECO) events in the Eocene succession of the Isle of Wight (UK)?

Wed, 06 May 2026 07:32:13 +0200

Can the distribution of foraminifera locate the Early Eocene Climatic Optimum (EECO) and Middle Eocene Climatic Optimum (MECO) events in the Eocene succession of the Isle of Wight (UK)?
Malcolm B. Hart, Mark E. A. Alex-Sanders, and Christopher W. Smart
J. Micropalaeontol., 45, 315–334, https://doi.org/10.5194/jm-45-315-2026, 2026
The paper describes the foraminifera of the Eocene in the area of the Hampshire Basin and the English Channel. Hyperthermal events (Early Eocene Climatic Optimum (EECO)) Late Lutetian Thermal Event (LLTE), and Middle Eocene Climatic Optimum (MECO)) are discussed and set in the context of global climate change in the Paleogene.

Comment on “Chronostratigraphic ranges of Early–Middle Miocene larger benthic foraminifera calibrated by planktonic foraminiferal assemblages (Sierra de Marmolance, Granada, SE Spain)” by Bolivar-Feriche et al. (2025)

Mon, 27 Apr 2026 07:32:13 +0200

Comment on “Chronostratigraphic ranges of Early–Middle Miocene larger benthic foraminifera calibrated by planktonic foraminiferal assemblages (Sierra de Marmolance, Granada, SE Spain)” by Bolivar-Feriche et al. (2025)
Cesare A. Papazzoni, Andrea Benedetti, Antonino Briguglio, Lorenzo Consorti, and György Less
J. Micropalaeontol., 45, 309–313, https://doi.org/10.5194/jm-45-309-2026, 2026
Oligocene fossils were retrieved from a Miocene deposit. Authors stated that their age should expand into the Miocene accordingly. Miocene age was not directly retrieved from the studied deposits but from a nearby outcrop not clearly connected to the studied succession. We argue that transportation events might have simply reworked Oligocene fossils into the Miocene material, as commonly occurs in ramp environments.

Planktic foraminiferal distribution across the Cretaceous–Paleogene (K–Pg) boundary from the Neuquén Basin (Cerro Azul section): biostratigraphy and paleoenvironmental significance

Wed, 15 Apr 2026 07:32:13 +0200

Planktic foraminiferal distribution across the Cretaceous–Paleogene (K–Pg) boundary from the Neuquén Basin (Cerro Azul section): biostratigraphy and paleoenvironmental significance
Guilherme Krahl, Andrea Concheyro, Marlone H. H. Bom, Rodrigo M. Guerra, Karlos G. D. Kochhann, Thorsten Bauersachs, Lorenz Schwark, Daiane Ceolin, Telma Musso, and Gerson Fauth
J. Micropalaeontol., 45, 297–308, https://doi.org/10.5194/jm-45-297-2026, 2026
The Maastrichtian–Danian record at Cerro Azul (Argentina) shows shifts in planktic foraminiferal assemblages and sea surface temperatures (SSTs) (TEXH86) tied to the K–Pg (Cretaceous–Paleogene) extinction. Guembelitriid dominance and high-latitude affinity define the early Danian, with Antarcticella pauciloculata present. At 45 cm above the boundary, tropical species appear with a ~1.5 °C SST rise, signalling initial post-extinction climatic recovery.

Dinoflagellate cysts as indicators of primary productivity along a Baltic Sea–North Sea–Atlantic transect

Tue, 14 Apr 2026 07:32:13 +0200

Dinoflagellate cysts as indicators of primary productivity along a Baltic Sea–North Sea–Atlantic transect
Cecile S. Hilgen, Rick Hennekam, Marcel T. J. van der Meer, Timme H. Donders, Gert-Jan Reichart, and Francesca Sangiorgi
J. Micropalaeontol., 45, 275–295, https://doi.org/10.5194/jm-45-275-2026, 2026
The Northwest European Shelf plays a key role in the global carbon cycle. To assess its past role, we want to reconstruct primary productivity using microfossils. By comparing surface sediment assemblages with sediment properties and modern environmental conditions, we found a good microfossil-based indicator for primary productivity. This indicator will be useful to reconstruct productivity in the past Northwest European Shelf.

New material of Schizopholis (family Botsfordiidae) from the Tsinghsutung Formation (Cambrian Series 2, Stage 4) in Songtao County, Guizhou Province, South China

Mon, 13 Apr 2026 07:32:14 +0200

New material of Schizopholis (family Botsfordiidae) from the Tsinghsutung Formation (Cambrian Series 2, Stage 4) in Songtao County, Guizhou Province, South China
Buqing Wei, Xinglian Yang, Dezhi Wang, Weiyi Wu, and Yongqin Mao
J. Micropalaeontol., 45, 259–273, https://doi.org/10.5194/jm-45-259-2026, 2026
Well-preserved fossils of Schizopholis were found in the Tsinghsutung Formation of Cambrian Series 2, Stage 4 in Songtao County, Guizhou Province by etching limestones with 3–5% acetic acid. This is the first systematic description of S. yorkensis from South China, and we extend its palaeobiogeographical distribution. Palaeobiogeographical analysis indicates that Schizopholis was predominantly distributed in low-latitude regions and reached its highest abundance/diversity level during the Cambrian Age 4.

Marine palynology of the Alano di Piave Bartonian–Priabonian Global Stratotype Section and Point, NE Italy

Thu, 02 Apr 2026 07:32:14 +0200

Marine palynology of the Alano di Piave Bartonian–Priabonian Global Stratotype Section and Point, NE Italy
Alexander J. P. Houben, Alina I. Iakovleva, Simone Galeotti, and Henk Brinkhuis
J. Micropalaeontol., 45, 219–257, https://doi.org/10.5194/jm-45-219-2026, 2026
Tiny fossils aged 40 x 106 years from an Italian rock section show that the ancient sea's environment was mostly stable. A global warming event caused wetter periods and river runoff into this sea. The study also provides fossil photos and introduces new types, important for future research.

Reassessment of the global distribution and diversity of modern planktonic foraminifera from the FORCIS database

Tue, 24 Mar 2026 07:32:14 +0100

Reassessment of the global distribution and diversity of modern planktonic foraminifera from the FORCIS database
Sonia Chaabane, Ralf Schiebel, Julie Meilland, Geert-Jan A. Brummer, P. Graham Mortyn, Olivier Sulpis, Thomas B. Chalk, Xavier Giraud, Helene Howa, Azumi Kuroyanagi, Gregory Beaugrand, and Thibault de Garidel-Thoron
J. Micropalaeontol., 45, 195–217, https://doi.org/10.5194/jm-45-195-2026, 2026
Using the FORCIS database, we mapped the distribution of planktonic goraminifera that record past ocean conditions. Our study reveals that these species mostly inhabit the upper ocean and thrive in waters ranging from −2 °C to over 31 °C. Their range is shifting, with species once limited to warm regions now appearing in cooler areas and smaller species increasing in number. This work refines our view of their biogeography and how climate change is reshaping ocean life.

Unraveling Southern Ocean diatom diversity across the Eocene–Oligocene transition

Mon, 16 Mar 2026 07:32:14 +0100

Unraveling Southern Ocean diatom diversity across the Eocene–Oligocene transition
Volkan Özen, Johan Renaudie, and David Lazarus
J. Micropalaeontol., 45, 177–194, https://doi.org/10.5194/jm-45-177-2026, 2026
The Eocene–Oligocene transition was a pivotal interval in Earth's geological history, marked by cooling and Antarctic glaciation. Our research explores how Southern Ocean diatoms responded to these changes. By analyzing records from multiple sites, we revealed previously unrecognized diatom diversity, and identified distinct patterns in diversity and extinction. These findings deepen our understanding of the interplay between climatic perturbations and the biosphere.

Early Eocene evolutionary trajectories within the Toweius genus: insights from a newly identified species in the equatorial Atlantic

Mon, 09 Mar 2026 07:32:14 +0100

Early Eocene evolutionary trajectories within the Toweius genus: insights from a newly identified species in the equatorial Atlantic
Joseph D. Asanbe and Jorijntje Henderiks
J. Micropalaeontol., 45, 159–175, https://doi.org/10.5194/jm-45-159-2026, 2026
Toweius was among the most widespread and important calcareous nannoplankton groups in the oceans 53 million years ago, playing a key role in the evolutionary transition to another prominent group during the Cenozoic (Reticulofenestra). Using detailed biometric measurements with high-resolution imaging, we describe a distinctive, smaller morphotype of Toweius. Our results indicate that this form evolved gradually through speciation, shedding light on the complex evolutionary dynamics of Toweius.

Developing a new species-level database of Cretaceous calcareous nannoplankton occurrences – Uneptune

Wed, 11 Feb 2026 07:32:14 +0100

Developing a new species-level database of Cretaceous calcareous nannoplankton occurrences – Uneptune
Yi Zhang, Jeremy R. Young, Paul R. Bown, Chengshan Wang, and Xi Chen
J. Micropalaeontol., 45, 147–157, https://doi.org/10.5194/jm-45-147-2026, 2026
We developed a new global database of microscopic fossil algae, known as calcareous nannoplankton, from Cretaceous ocean sediments to improve the understanding of ancient oceans and climate change. By integrating data from numerous published studies and standardising species names and ages, we created the Uneptune database with about 175 000 fossil records. Hosted on the Nannotax website, it provides visualisation tools that help scientists explore global marine ecosystems during the Cretaceous.

Environmental changes at the seafloor of the Faro drift (Gulf of Cadiz) during the transition from the Early to the Middle Pleistocene

Fri, 30 Jan 2026 07:32:14 +0100

Environmental changes at the seafloor of the Faro drift (Gulf of Cadiz) during the transition from the Early to the Middle Pleistocene
Giulia Silveira Molina, Gerhard Schmiedl, Francisco Jiménez-Espejo, Henning Kuhnert, Teresa Rodrigues, and Antje Helga Luise Voelker
J. Micropalaeontol., 45, 117–145, https://doi.org/10.5194/jm-45-117-2026, 2026
Benthic foraminifera from sediment cores collected in the Gulf of Cadiz were analysed to track ocean changes between 1014 and 761 kyr ago. Our results reveal shifts in species composition throughout the climate cycles. Oxygen loss occurred in the Mediterranean Outflow Water during warmer periods when solar insolation was intensified and productivity was higher. During cold periods, stronger bottom currents were identified by sand content and the abundance of the species Planulina ariminensis.

Automated identification of fossil benthic foraminifera from the Peruvian margin using convolutional neural networks

Mon, 26 Jan 2026 07:32:14 +0100

Automated identification of fossil benthic foraminifera from the Peruvian margin using convolutional neural networks
Sikandar Hayat, Meryem Mojtahid, Mary Elliot, Jorge Cardich, Emmanuelle Geslin, Thibault de Garidel-Thoron, Matthieu Carré, and Christine Barras
J. Micropalaeontol., 45, 95–116, https://doi.org/10.5194/jm-45-95-2026, 2026
We studied how artificial intelligence can speed up the study of tiny ocean organisms called benthic foraminifera, whose shells help scientists understand past ocean changes. Normally, identifying and counting them under a microscope takes a lot of time and skill. Here, we compared automated image analysis and human counting for 31 samples. The automated method showed promising results for faster and reliable research.

Early–Middle Ordovician chitinozoans from the Dawan Formation, Yichang area, Central China

Mon, 26 Jan 2026 07:32:14 +0100

Early–Middle Ordovician chitinozoans from the Dawan Formation, Yichang area, Central China
Yan Liang, Shouhan Wu, Xiaocong Luan, and Renbin Zhan
J. Micropalaeontol., 45, 73–93, https://doi.org/10.5194/jm-45-73-2026, 2026
A study on Ordovician chitinozoans from South China was conducted. A total of 13 genera and 31 taxa are recognised, including 3 new taxa. Systematic and biostratigraphic remarks are provided for key or disputed taxa to foster our understanding of their classification and biostratigraphy. Furthermore, network analysis is applied for the first time to assess their palaeoenvironmental significance, yielding positive results that highlight a promising new research direction in chitinozoan studies.

Seasonal dynamics of mudflat foraminifera linked to diatom species and traits

Thu, 15 Jan 2026 07:32:14 +0100

Seasonal dynamics of mudflat foraminifera linked to diatom species and traits
Constance Choquel, Emmanuelle Geslin, Edouard Metzger, Bruno Jesus, Antoine Prins, Emilie Houliez, Magali Schweizer, Thierry Jauffrais, Éric Bénéteau, and Aurélia Mouret
J. Micropalaeontol., 45, 51–72, https://doi.org/10.5194/jm-45-51-2026, 2026
We studied how tiny shelled organisms called foraminifera living in coastal mudflats respond to changes in their microscopic algae food. By monitoring a French mudflat every month for 3 years, we showed that seasonal environmental changes strongly shape both algae and foraminifera. Using simple algae traits such as size and shape explained feeding patterns better than identifying algae species, offering a clearer way to predict ecosystem responses to environmental change.

Morphometric divergence in Cyprideis (Ostracoda) during the Middle and Late Miocene of the Central Paratethys realm

Fri, 09 Jan 2026 07:32:14 +0100

Morphometric divergence in Cyprideis (Ostracoda) during the Middle and Late Miocene of the Central Paratethys realm
Radovan Pipík, Martin Gross, and Dušan Starek
J. Micropalaeontol., 45, 33–50, https://doi.org/10.5194/jm-45-33-2026, 2026
The story of Cyprideis pannonica offers a fascinating insight into how environmental change shapes biodiversity. Over 2 million years, this tiny ostracod adapted to habitats that transformed from a sea into a lake. Originally varied in shape and size, Cyprideis diversified into many species during periods of ecological complexity. These findings demonstrate that even small organisms can reveal big evolutionary patterns – linking habitat changes, speciation, and adaptation within a dynamic landscape.

Comment on “Detailed conodont data from the Olenekian–Anisian boundary interval of the GSSP candidate section at Deşli Caira, Romania” by Golding (2025)

Thu, 08 Jan 2026 07:32:14 +0100

Comment on “Detailed conodont data from the Olenekian–Anisian boundary interval of the GSSP candidate section at Deşli Caira, Romania” by Golding (2025)
Marco Balini, Micha Horacek, and Iuliana Lazăr
J. Micropalaeontol., 45, 27–31, https://doi.org/10.5194/jm-45-27-2026, 2026
The tectonic setting of the Deşli Caira section that was overlooked by Martyn Golding in his paper on the Olenekian/Anisian conodonts from the Deşli Caira section (Romania) is clarified. The sedimentary succession is faulted, but the offset is very minor and easy to detect. Unfortunately the author did not take the fault into account; therefore, the stratigraphic position of his samples is uncertain.

Tropical ecosystem shifts at the Eocene–Oligocene transition in the southwestern Caribbean region

Tue, 06 Jan 2026 07:32:14 +0100

Tropical ecosystem shifts at the Eocene–Oligocene transition in the southwestern Caribbean region
Raúl Trejos-Tamayo, Darwin Garzón, Diana Ochoa, Angelo Plata-Torres, Fabrizio Frontalini, Felipe Vallejo-Hincapié, Fátima Abrantes, Vitor Magalhães, Viviana Arias-Villegas, Carlos Jaramillo, Jaime Escobar, Jason H. Curtis, José-Abel Flores, Constanza Osorio-Tabares, Mónica Duque-Castaño, Erika Bedoya, and Andrés Pardo-Trujillo
J. Micropalaeontol., 45, 1–25, https://doi.org/10.5194/jm-45-1-2026, 2026
Our study investigates how tropical marine ecosystems responded to climate change during the Eocene–Oligocene transition (~34 Ma). Based on microfossil and geochemical data from a Caribbean drill core, we identify enhanced terrigenous input, increased surface productivity, changes in carbonate preservation, and reduced deep-water oxygenation. Likely driven by global cooling and sea-level fall, these shifts offer new insights into low-latitude paleoenvironmental change.

Deep-sea benthic foraminiferal response to the Late Lutetian Thermal Maximum at Demerara Rise (ODP Site 1260, equatorial western Atlantic)

Fri, 19 Dec 2025 07:32:14 +0100

Deep-sea benthic foraminiferal response to the Late Lutetian Thermal Maximum at Demerara Rise (ODP Site 1260, equatorial western Atlantic)
Irene Peñalver-Clavel, Thomas Westerhold, and Laia Alegret
J. Micropalaeontol., 44, 713–731, https://doi.org/10.5194/jm-44-713-2025, 2025
A study in the equatorial Atlantic Ocean (Ocean Drilling Program Site 1260) reveals the deep-sea biotic response to a middle Eocene warming event 41.52 million years ago. Low-diversity benthic foraminiferal assemblages indicate environmental stress during the warming event. We argue that the biotic response in the deep sea and carbonate dissolution at this site were likely related to its paleoceanographic setting.

Deep learning accurately identifies fjord benthic foraminifera

Wed, 17 Dec 2025 07:32:14 +0100

Deep learning accurately identifies fjord benthic foraminifera
Marko Plavetić, Allison Yi Hsiang, Mats Josefson, Gustaf Hulthe, and Irina Polovodova Asteman
J. Micropalaeontol., 44, 693–711, https://doi.org/10.5194/jm-44-693-2025, 2025
Foraminifera are promising bioindicators in coastal environments, yet their manual identification is slow and relies on taxonomic expertise. Deep learning and neural networks can quickly recognize morphological differences. Here, fjord foraminifera were imaged, labeled, and classified in the Roboflow application programming interface, resulting in 22 138 labelled individuals. These were used to train a deep learning model, which successfully distinguished among 29 species with up to 90.3 % precision.