Journal of Agricultural, Biological and Environmental Statistics
Understanding past extinction processes is an important and current matter, and regression method... more Understanding past extinction processes is an important and current matter, and regression methods in the domain of survival analysis can be applied to fossil data. The chief goal of this study is to relate genus-level lifetimes to ancient environmental conditions (e.g., sea level and surface temperatures or carbon dioxide concentration). The Cox proportional hazards model was used to characterize the extinction risks of marine genera, enabling quantitative and graphical comparisons between selected taxonomic groups over geologic time. The environment was confirmed to be a significant factor, and both age-dependent coefficients and time-dependent covariates were required to accommodate the data. The Cox model analyzed in this study provides new insights into the extinction patterns of marine biota over the past 538.8 million years (Ma). Previous works focusing on specific groups at certain geologic times suggest that the extinction risk is related to taxa age, taxonomic group, and, ...
The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorica... more The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorican Island during the K/Pg crisis.
The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorica... more The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorican Island during the K/Pg crisis.
The Fontllonga section is one of the best-known stratigraphic sections wordwide for the study of ... more The Fontllonga section is one of the best-known stratigraphic sections wordwide for the study of charophyte biostratigraphy of the Maastrichtian and lower Palaeocene. An updated proposal for the charophyte biostratigraphy of this section is presented after summarizing previous knowledge. The zone of Peckichara cancellata allows the upper Campanian–lowermost Maastrichtian to be characterised in the base of the section (La Macana Formation). The Microchara punctata biozone represents most of the Maastrichtian (Figuerola Formation). Within this biozone, a Clavator ultimus subzone is proposed to improve characterisation of the lower and middle Maastrichtian. Both the upper and lower boundaries of the Microchara punctata biozone proposed in previous studies are modified based on new occurrences of the index species. A charophyte assemblage belonging to the Dughiella bacillaris biozone is reported for the first time from the middle of the section (Perauba Complex) and provides an age for ...
Abstract The Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment ... more Abstract The Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment in charophyte evolution, marked by the extinction of two important Mesozoic families, the Porocharaceae and the Clavatoraceae, and a major turnover within the Characeae. However, new data presented here suggest that one species of the European Porocharaceae (based on gyrogonites) and one species of the Clavatoraceae (based on thalli), persisted into the basal Danian. In addition, a taxonomic revision of the Characeae, coupled with an updated biostratigraphy, shows that this family underwent a step-wise extinction during the latest Cretaceous with only a small number of species becoming extinct at the K/Pg boundary. As a result, changes in charophyte floras around the K/Pg boundary in Europe cannot be considered to represent a major turnover in charophyte evolution. Its effects were more comparable to a normal stage boundary event rather than to a major erathem boundary one. Similar disappearance patterns at the K/Pg boundary have also been recorded in other taxa, including fish and amphibians, showing that aquatic freshwater biotas may somehow be resilient to catastrophic events such as those that occurred during the K/Pg crisis.
Journal of Agricultural, Biological and Environmental Statistics
Understanding past extinction processes is an important and current matter, and regression method... more Understanding past extinction processes is an important and current matter, and regression methods in the domain of survival analysis can be applied to fossil data. The chief goal of this study is to relate genus-level lifetimes to ancient environmental conditions (e.g., sea level and surface temperatures or carbon dioxide concentration). The Cox proportional hazards model was used to characterize the extinction risks of marine genera, enabling quantitative and graphical comparisons between selected taxonomic groups over geologic time. The environment was confirmed to be a significant factor, and both age-dependent coefficients and time-dependent covariates were required to accommodate the data. The Cox model analyzed in this study provides new insights into the extinction patterns of marine biota over the past 538.8 million years (Ma). Previous works focusing on specific groups at certain geologic times suggest that the extinction risk is related to taxa age, taxonomic group, and, ...
The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorica... more The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorican Island during the K/Pg crisis.
The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorica... more The supplementary data uploaded help to shed light into charophyte taxonomy in the Ibero-Armorican Island during the K/Pg crisis.
The Fontllonga section is one of the best-known stratigraphic sections wordwide for the study of ... more The Fontllonga section is one of the best-known stratigraphic sections wordwide for the study of charophyte biostratigraphy of the Maastrichtian and lower Palaeocene. An updated proposal for the charophyte biostratigraphy of this section is presented after summarizing previous knowledge. The zone of Peckichara cancellata allows the upper Campanian–lowermost Maastrichtian to be characterised in the base of the section (La Macana Formation). The Microchara punctata biozone represents most of the Maastrichtian (Figuerola Formation). Within this biozone, a Clavator ultimus subzone is proposed to improve characterisation of the lower and middle Maastrichtian. Both the upper and lower boundaries of the Microchara punctata biozone proposed in previous studies are modified based on new occurrences of the index species. A charophyte assemblage belonging to the Dughiella bacillaris biozone is reported for the first time from the middle of the section (Perauba Complex) and provides an age for ...
Abstract The Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment ... more Abstract The Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment in charophyte evolution, marked by the extinction of two important Mesozoic families, the Porocharaceae and the Clavatoraceae, and a major turnover within the Characeae. However, new data presented here suggest that one species of the European Porocharaceae (based on gyrogonites) and one species of the Clavatoraceae (based on thalli), persisted into the basal Danian. In addition, a taxonomic revision of the Characeae, coupled with an updated biostratigraphy, shows that this family underwent a step-wise extinction during the latest Cretaceous with only a small number of species becoming extinct at the K/Pg boundary. As a result, changes in charophyte floras around the K/Pg boundary in Europe cannot be considered to represent a major turnover in charophyte evolution. Its effects were more comparable to a normal stage boundary event rather than to a major erathem boundary one. Similar disappearance patterns at the K/Pg boundary have also been recorded in other taxa, including fish and amphibians, showing that aquatic freshwater biotas may somehow be resilient to catastrophic events such as those that occurred during the K/Pg crisis.
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