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Preprints

Filtering by Subject: Paleontology

First documented record of the ammonite Turrilites costatus LAMARCK, 1801 from the Cenomanian of northern Saudi Arabia: Implications for Arabian Plate paleogeography

ABDULLAH HOMOUD ALRWAILI

Published: 2025-10-19
Subjects: Earth Sciences, Paleontology, Physical Sciences and Mathematics

This study presents the first documented occurrence of the heteromorph ammonite genus Turrilites LAMARCK, 1801, from the Cretaceous strata of the Kingdom of Saudi Arabia. A dense, in-situ fossil assemblage, dominated by numerous specimens identified as Turrilites costatus LAMARCK, 1801, was discovered in an outcrop of the Aruma Formation located 9.5 km south of the city of Ar’ar in northern Saudi [...]

Eocene lacustrine–volcaniclastic deposits at Aliabad (Central Iran): A possible Proto-basin of the Oligo-Miocene Qom Formation

Mahdokht Karimi, Abdolhossein Amini, Nasrollah Abbassi, et al.

Published: 2025-10-14
Subjects: Earth Sciences, Geology, Paleobiology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology

Central Iran hosts intricate Cenozoic successions where the Oligo‑Miocene Qom Formation forms a major hydrocarbon reservoir. The stratigraphic and paleoenvironmental relationship of the Eocene Aliabad deposits to this formation has been controversial. This study integrates stratigraphic logging, petrography, geochemistry (XRD/XRF), and ichnology on 46 thin sections from Aliabad and 157 [...]

Author citation metrics in paleontology: the h-index and the c-score

Valentí Rull

Published: 2025-10-08
Subjects: Paleontology

The “Stanford ranking” (SR) of standardized citation indicators calculates an individual scientist’s composite c-score, addressing limitations of the h-index. Updated annually, the SR lists the top 100,000 scientists and the top 2% in each specialty. This study examines all (500) palaeontologists included in the SR (SR-palaeontologists), comparing their h-index, c-score and related productivity [...]

Unraveling Southern Ocean Diatom Diversity Across the Eocene/Oligocene Transition

Volkan Özen, Johan Renaudie, David Lazarus

Published: 2025-09-09
Subjects: Biodiversity, Earth Sciences, Paleobiology, Paleontology

The Eocene-Oligocene transition (EOT) was a critical interval of global cooling and circulation change that reshaped marine ecosystems. However, current knowledge of diatom diversity and community dynamics during this interval relies mainly on biostratigraphic compilations, which largely document common species and thus likely underestimate true diversity. This study provides a more complete [...]

Out of Afar: the first hominin migration? Long-term landscape changes in the Afar region and implications for hominin bipedalism

Ian George Smith, Sally Christine Reynolds

Published: 2025-07-19
Subjects: Paleontology

Climate change in Africa has long been considered to be a key driver in hominin behavioural adaptations such as bipedalism. The prevailing argument holds that open grasslands favoured the adoption of bipedalism, which can be defined as one of three types: facultative, habitual, and obligate. Across Africa, only one region, Ethiopia, shows evidence of hominins showing all three types of [...]

Continental-Scale Carbonate Sedimentation and Environmental Correlates of the Shuram-Wonoka Excursion

Daniel Christian Segessenman, Shanan E Peters

Published: 2025-07-01
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy

Strata of the Ediacaran Period record many Earth-Life features that distinguish the Neoproterozoic-Phanerozoic transition. However, it is difficult to determine cause and effect relationships between Ediacaran events. Continental-scale patterns of sedimentation have been used as proxies to investigate controls on Phanerozoic macroevolution, including sea level drivers and potential carbon cycling [...]

Weakening of AMOC linked to past Greenland Ice Sheet retreat

Daniel Parkes, David J. Thornalley, Erin McClymont, et al.

Published: 2025-03-22
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Geochemistry, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Paleontology, Physical Sciences and Mathematics

A weakening of the Atlantic Meridional Overturning Circulation (AMOC) is predicted to occur under multiple scenarios of future warming. However, the effect of meltwater from a decaying Greenland Ice Sheet (GrIS) on AMOC is uncertain. Using a basin-wide network of North Atlantic sediment cores, we show that the largescale melting of the GrIS during a previous interglacial (Marine Isotope Stage 11c [...]

Ediacaran coupling of climate and biosphere dynamics

Thomas William Wong Hearing, Benjamin Tindal, Thomas M. Vandyk, et al.

Published: 2025-03-15
Subjects: Climate, Glaciology, Paleontology, Sedimentology, Stratigraphy

Throughout the Phanerozoic (538.8 Ma to present), climate change is demonstrably linked to radiations, extinctions, and turnovers in the biosphere. Here, we show that this connection existed in the late Ediacaran (~579 to 538.8 Ma), the first interval in Earth’s history to host complex macro-organisms, including early metazoans. Current correlations of glacial sedimentary deposits have been used [...]

A comment on the indicator capacity of Artemisia pollen in pre-Holocene paleoecology

Valentí Rull

Published: 2025-03-08
Subjects: Paleontology

In pre-Holocene paleoecology, Artemisia (Asteraceae) pollen is commonly considered an indicator of arid steppic environments in temperate regions. However, the >520 known species of this genus occur across a wide range of bioclimatic conditions. This paper comments on a recent comprehensive study that examined the identification of Artemisia pollen at the species level in relation to the [...]

Drastic Changes in Atmospheric CO2 Concentration Led to Biological Mass Extinction and Explosion

Bilu Huang

Published: 2025-03-08
Subjects: Earth Sciences, Environmental Sciences, Paleontology

When the area of polar ice caps expands to a certain threshold, a positive feedback effect will occur. Due to the strong reflection of sunlight by ice and snow, the global climate will become cold and dry. CO₂ in the atmosphere will be rapidly sequestered in the seabed and permafrost through the biological carbon pump, thereby affecting plant photosynthesis, reducing NPP and the nutritional value [...]

Middle Miocene Mediterranean mangroves and potential modern analogs

Valentí Rull, Isaac Casanovas-Vilar, Alba Vicente

Published: 2025-02-25
Subjects: Paleontology

During the Miocene Climatic Optimum (MCO; 17–15 Ma), the northern boundary of mangroves – now situated at ~30° N – extended along the northern Mediterranean coasts (~45° N). These Avicennia-only mangroves have been considered impoverished mangroves controlled by the general latitudinal temperature gradient. The MCO Mediterranean mangroves have been compared with the extant Middle East (ME) [...]

Where has all the Sinter gone? From the Pink and White Terraces, the Greatest Tourist Attraction of the Southern Hemisphere

Rex Bunn

Published: 2025-02-02
Subjects: Environmental Studies, Geology, Geomorphology, Other Geography, Paleontology, Physical and Environmental Geography, Spatial Science, Stratigraphy, Volcanology

Debate continues over the silica sinter Pink and White Terraces, the greatest tourist attraction of the southern hemisphere. The 1886 Tarawera eruption may or may not have destroyed them by burial or eruption. This research compiles surviving sinter. The volume is unexpectedly tiny, which bears on the debate. A database was developed including photography. A forensic approach was taken to [...]

A critical evaluation of fossil pollen records from the mangrove tree Pelliciera beyond the Neotropics: biogeographical and evolutionary implications

Valentí Rull

Published: 2024-12-13
Subjects: Paleontology

Pelliciera is a Neotropical mangrove tree restricted to a small region around the Panama Isthmus. In the past, this taxon was distributed across much of the Neotropics, reaching its maximum extent during the Oligo-Miocene. The occurrence of Pelliciera outside the Neotropics had been debated based on a few fossil pollen records from Africa and Europe, though many of these records have been [...]

Miocene ant-mealybug trophobiosis imaged with X-Ray micro-computed tomography

Ru Smith

Published: 2024-10-27
Subjects: Paleobiology, Paleontology, Research Methods in Life Sciences

Amber is a remarkable preserving medium for Mesozoic and Cenozoic terrestrial biotas, but even when transparency is good, available viewing angles can be limited. The technique of X-ray micro-computed tomography allows inspection from any desired viewpoint and facilitates detailed anatomical measurements, avoiding parallax errors. Here, I show the use of this technique to study an extremely rare [...]

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