Pub Date : 2023-12-05DOI: 10.1101/2023.12.04.569281
Maria Antonieta Lorente, Christopher Noto, Peter Flaig
The Arlington Archosaur Site (AAS) between Dallas and Fort Worth, Texas, is known as a rich fossiliferous section. The age of these rocks is generally considered to be mid Cenomanian, but conflicting evidence suggests the age may be as young as the late Cenomanian early Turonian. To address the issue, a palynological study was designed and conducted based on the close sampling of the lithofacies. Palynological samples were processed according to the standard acid preparation. The study was quantitative and focused on associations to determine the paleoenvironment, paleoclimate, biostratigraphy, and age of exposure. The rich palynological assemblages comprise spores from seedless plants, gymnosperms, angiosperms, fungi, algae, and dinoflagellate cysts. Bryophytes were abundant mainly in Facies A and B, with Zlivisporis cenomanianus taking over the bryophytes' habitat in Facies D. Lycophytes abundant in the alluvial and coastal plains are considered to have been transported. Conifers were the predominant group of gymnosperms, also mainly transported into the section. Freshwater algal remains include Schizophacus laevigatus/Ovoidites parvus, Schizosporis reticulatus, Botryococcus sp., and Pediastrum sp. Acanthomorph acritarchs present in low abundance and diversity appear following shallow marine dinoflagellates' spikes and before freshwater colonial algal spikes. The vegetation signal at Noto's Facies A and B indicates tropical to subtropical shallow marine to coastal plains, while Noto's Facies D indicates tidally influenced areas. Also, picks of the diversity and abundance of dinoflagellate cysts are interpreted as an increased marine influence and proposed as possible flooding surfaces. The results support the alternation of marine incursions within deltaic and floodplain sequences, related to regional climate oscillation that affected the vegetation on the upland drainage area. Key palynological markers point to an early Late Cenomanian age, and the presence of the Cyclonephelium compactum - C. membraniphorum (Ccm morphological plexus) signals that the incursion of boreal waters during the Plenus Cold Event of the Ocean Anoxic Event 2 may have reached as far south as the AAS area. This coincides with vegetation trends that suggest a cooler and less humid climate at the start of Facies A, where Ccm is more abundant.
{"title":"A Glimpse Into the Cenomanian: Palynology of the Arlington Archosaur Site, Late Cretaceous Western Interior Seaway, Texas, USA","authors":"Maria Antonieta Lorente, Christopher Noto, Peter Flaig","doi":"10.1101/2023.12.04.569281","DOIUrl":"https://doi.org/10.1101/2023.12.04.569281","url":null,"abstract":"The Arlington Archosaur Site (AAS) between Dallas and Fort Worth, Texas, is known as a rich fossiliferous section. The age of these rocks is generally considered to be mid Cenomanian, but conflicting evidence suggests the age may be as young as the late Cenomanian early Turonian. To address the issue, a palynological study was designed and conducted based on the close sampling of the lithofacies. Palynological samples were processed according to the standard acid preparation. The study was quantitative and focused on associations to determine the paleoenvironment, paleoclimate, biostratigraphy, and age of exposure. The rich palynological assemblages comprise spores from seedless plants, gymnosperms, angiosperms, fungi, algae, and dinoflagellate cysts. Bryophytes were abundant mainly in Facies A and B, with Zlivisporis cenomanianus taking over the bryophytes' habitat in Facies D. Lycophytes abundant in the alluvial and coastal plains are considered to have been transported. Conifers were the predominant group of gymnosperms, also mainly transported into the section. Freshwater algal remains include Schizophacus laevigatus/Ovoidites parvus, Schizosporis reticulatus, Botryococcus sp., and Pediastrum sp. Acanthomorph acritarchs present in low abundance and diversity appear following shallow marine dinoflagellates' spikes and before freshwater colonial algal spikes. The vegetation signal at Noto's Facies A and B indicates tropical to subtropical shallow marine to coastal plains, while Noto's Facies D indicates tidally influenced areas. Also, picks of the diversity and abundance of dinoflagellate cysts are interpreted as an increased marine influence and proposed as possible flooding surfaces. The results support the alternation of marine incursions within deltaic and floodplain sequences, related to regional climate oscillation that affected the vegetation on the upland drainage area. Key palynological markers point to an early Late Cenomanian age, and the presence of the Cyclonephelium compactum - C. membraniphorum (Ccm morphological plexus) signals that the incursion of boreal waters during the Plenus Cold Event of the Ocean Anoxic Event 2 may have reached as far south as the AAS area. This coincides with vegetation trends that suggest a cooler and less humid climate at the start of Facies A, where Ccm is more abundant.","PeriodicalId":501477,"journal":{"name":"bioRxiv - Paleontology","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138535402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1101/2023.11.27.568675
Paul D Bons, Catherine C Bauer, Lydia J Papkalla
In their paper 'A refined proposal for the origin of dogs: the case study of Gnirshoehle, a Magdalenian cave site', Baumann and colleagues claim that their data 'support the hypothesis that the Hegau Jura was a potential center of early European wolf domestication', and that 'such a scenario becomes plausible considering a close proximity of canids and humans thereby introducing a controlled, or at least a restrictive diet'. The study focusses on fossil remains of 'large canids' from the Gnirshoehle cave site in SW Germany. Morphometric data on only one specimen, GN-999, as well as collagen delta15N and delta13C isotopic data and mitochondrial DNA analyses on the Gnirshoehle specimens and a comparative sample were used to conclude that the Gnirshoehle specimens shed light on the 'origin of dogs' as purported by the title of the paper. Here we argue that the paper is fundamentally flawed and excluded available relevant data.
{"title":"Dietary reconstructions of Magdalenian canids from SW-Germany do not indicate that the area was a centre of early European wolf domestication","authors":"Paul D Bons, Catherine C Bauer, Lydia J Papkalla","doi":"10.1101/2023.11.27.568675","DOIUrl":"https://doi.org/10.1101/2023.11.27.568675","url":null,"abstract":"In their paper 'A refined proposal for the origin of dogs: the case study of Gnirshoehle, a Magdalenian cave site', Baumann and colleagues claim that their data 'support the hypothesis that the Hegau Jura was a potential center of early European wolf domestication', and that 'such a scenario becomes plausible considering a close proximity of canids and humans thereby introducing a controlled, or at least a restrictive diet'. The study focusses on fossil remains of 'large canids' from the Gnirshoehle cave site in SW Germany. Morphometric data on only one specimen, GN-999, as well as collagen delta15N and delta13C isotopic data and mitochondrial DNA analyses on the Gnirshoehle specimens and a comparative sample were used to conclude that the Gnirshoehle specimens shed light on the 'origin of dogs' as purported by the title of the paper. Here we argue that the paper is fundamentally flawed and excluded available relevant data.","PeriodicalId":501477,"journal":{"name":"bioRxiv - Paleontology","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138535406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the first continuous (gap-free) Lateglacial-Early Holocene (LGEH) pollen record for the Iberian Pyrenees resolved at centennial resolution. The main aims are (i) to provide a standard chronostratigraphic correlation framework, (ii) to unravel the relationships between vegetation shifts, climatic changes and fire, and (iii) to obtain a regional picture of LGEH vegetation for the Pyrenees and the surrounding lowlands. Seven pollen assemblage zones were obtained and correlated with the stadial/interstadial phases of the Greenland ice cores that serve as a global reference. Several well-dated datums were also derived for keystone individual taxa that are useful for correlation purposes. Four vegetation types were identified, two of them corresponding to conifer and deciduous forests (Cf, Df) and two representing open vegetation types (O1, O2) with no modern analogs, dominated by Artemisia-Poaceae and Saxifraga-Cichiroideae, respectively. Forests dominated during interstadial phases (Bolling/Allerod and Early Holocene), whereas O1 dominated during stadials (Oldest Dryas and Younger Dryas), with O2 being important only in the first half of the Younger Dryas stadial. The use of pollen-independent proxies for temperature and moisture allowed the reconstruction of paleoclimatic trends and the responses of the four vegetation types defined. The most relevant observation in this sense was the finding of wet climates during the Younger Dryas, which challenges the traditional view of arid conditions for this phase on the basis of former pollen records. Fire incidence was low until the early Holocene, when regional fires were exacerbated, probably due to the combination of higher temperatures and forest biomass accumulation. These results are compared with the pollen records available for the whole Pyrenean range and the surrounding lowlands within the framework of elevational, climatic and biogeographical gradients. Some potential future developments are suggested on the basis of the obtained results, with an emphasis on the reconsideration of the LGEH spatiotemporal moisture patterns and the comparison of the Pyrenees with other European ranges from different climatic and biogeographical regions.
{"title":"A continuous centennial Lateglacial-Early Holocene (15-10 cal kyr BP) palynological record from the Iberian Pyrenees and regional comparisons","authors":"Valenti Rull, Arnau Blasco, Miguel Angel Calero, Maarten Blaauw, Teresa Vegas-Vilarrubia","doi":"10.1101/2023.07.02.547433","DOIUrl":"https://doi.org/10.1101/2023.07.02.547433","url":null,"abstract":"This paper presents the first continuous (gap-free) Lateglacial-Early Holocene (LGEH) pollen record for the Iberian Pyrenees resolved at centennial resolution. The main aims are (i) to provide a standard chronostratigraphic correlation framework, (ii) to unravel the relationships between vegetation shifts, climatic changes and fire, and (iii) to obtain a regional picture of LGEH vegetation for the Pyrenees and the surrounding lowlands. Seven pollen assemblage zones were obtained and correlated with the stadial/interstadial phases of the Greenland ice cores that serve as a global reference. Several well-dated datums were also derived for keystone individual taxa that are useful for correlation purposes. Four vegetation types were identified, two of them corresponding to conifer and deciduous forests (Cf, Df) and two representing open vegetation types (O1, O2) with no modern analogs, dominated by Artemisia-Poaceae and Saxifraga-Cichiroideae, respectively. Forests dominated during interstadial phases (Bolling/Allerod and Early Holocene), whereas O1 dominated during stadials (Oldest Dryas and Younger Dryas), with O2 being important only in the first half of the Younger Dryas stadial. The use of pollen-independent proxies for temperature and moisture allowed the reconstruction of paleoclimatic trends and the responses of the four vegetation types defined. The most relevant observation in this sense was the finding of wet climates during the Younger Dryas, which challenges the traditional view of arid conditions for this phase on the basis of former pollen records. Fire incidence was low until the early Holocene, when regional fires were exacerbated, probably due to the combination of higher temperatures and forest biomass accumulation. These results are compared with the pollen records available for the whole Pyrenean range and the surrounding lowlands within the framework of elevational, climatic and biogeographical gradients. Some potential future developments are suggested on the basis of the obtained results, with an emphasis on the reconsideration of the LGEH spatiotemporal moisture patterns and the comparison of the Pyrenees with other European ranges from different climatic and biogeographical regions.","PeriodicalId":501477,"journal":{"name":"bioRxiv - Paleontology","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138535405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.1101/2021.06.10.447946
Valentin Samuel Kelz, Pauline Guenser, Manuel Rigo, Emilia Jarochowska
Conodont elements have high rates of morphological evolution, but the drivers of this disparity are debated. Positive allometric relationships between dimensions of food-processing surfaces and entire P1 elements have been used in to argue that these elements performed mechanical digestion. If involved in food processing, the surface of the element should grow at a rate proportional to the increase in energy requirements of the animal. This inference of function relies on the assumption that the energy requirements of the animal grew faster (≅ mass0.75) than the tooth area (≅ mass0.67). We re-evaluate this assumption based on metabolic rates across animals, and calculate the allometry in platform-bearing P1 elements of Late Triassic co-occurring taxa, Metapolygnathus communisti and Epigondolella rigoi, using 3D models of ontogenetic series. Positive allometry is found in platform and element dimensions in both species, supporting a grasping-tooth hypothesis, based on the assumption that metabolic rate in conodonts scaled with body mass similarly to that in fish and ectoterms. We also calculate the curvature of P1 platform surface using the Dirichlet Normal Energy (DNE) as a proxy for diet. DNE values increase with body mass, supporting the assumption that conodont metabolic rates increased faster than mass0.67. We finally find that adults in both taxa differ in their food bases, which supports trophic diversification as an important driver of the remarkable disparity of conodont elements.
{"title":"Growth allometry and dental topography in Upper Triassic conodonts support trophic differentiation and molar-like element function","authors":"Valentin Samuel Kelz, Pauline Guenser, Manuel Rigo, Emilia Jarochowska","doi":"10.1101/2021.06.10.447946","DOIUrl":"https://doi.org/10.1101/2021.06.10.447946","url":null,"abstract":"Conodont elements have high rates of morphological evolution, but the drivers of this disparity are debated. Positive allometric relationships between dimensions of food-processing surfaces and entire P1 elements have been used in to argue that these elements performed mechanical digestion. If involved in food processing, the surface of the element should grow at a rate proportional to the increase in energy requirements of the animal. This inference of function relies on the assumption that the energy requirements of the animal grew faster (≅ mass<sup>0.75</sup>) than the tooth area (≅ mass<sup>0.67</sup>). We re-evaluate this assumption based on metabolic rates across animals, and calculate the allometry in platform-bearing P1 elements of Late Triassic co-occurring taxa, Metapolygnathus communisti and Epigondolella rigoi, using 3D models of ontogenetic series. Positive allometry is found in platform and element dimensions in both species, supporting a grasping-tooth hypothesis, based on the assumption that metabolic rate in conodonts scaled with body mass similarly to that in fish and ectoterms. We also calculate the curvature of P1 platform surface using the Dirichlet Normal Energy (DNE) as a proxy for diet. DNE values increase with body mass, supporting the assumption that conodont metabolic rates increased faster than mass<sup>0.67</sup>. We finally find that adults in both taxa differ in their food bases, which supports trophic diversification as an important driver of the remarkable disparity of conodont elements.","PeriodicalId":501477,"journal":{"name":"bioRxiv - Paleontology","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138535404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-27DOI: 10.1101/2022.09.25.509361
Valenti Rull
The concept of taxon cycle involves successive range expansions and contractions over time through which a species can indefinitely maintain its core distribution. Otherwise, it becomes extinct. Taxon cycles have been defined mostly for tropical island faunas, examples from continental areas are scarce and similar case studies for plants remain unknown. Most taxon cycles have been identified on the basis of phylogeographic studies, and straightforward empirical evidence from fossils is lacking. Here, empirical fossil evidence is provided for recurrent Eocene to present expansion/contraction cycles in a mangrove taxon (Pelliciera), after a Neotropical-wide study of the available pollen records. This recurrent behavior is compatible with the concept of taxon cycle from biogeographical, chronological and ecological perspectives. The biotic and abiotic drivers potentially involved in the initiation and maintenance of the Pelliciera expansion/contraction cycles are analyzed, and the ecological and evolutionary implications are discussed. Whether this could be a trend toward extinction is considered under the predictions of the taxon cycle theory. The recurrent expansion and contraction cycles identified for Pelliciera have strong potential for being the first empirically and unequivocally documented taxon cycles and likely the only taxon cycles documented to date for plants.
{"title":"Taxon cycles in Neotropical mangroves","authors":"Valenti Rull","doi":"10.1101/2022.09.25.509361","DOIUrl":"https://doi.org/10.1101/2022.09.25.509361","url":null,"abstract":"The concept of taxon cycle involves successive range expansions and contractions over time through which a species can indefinitely maintain its core distribution. Otherwise, it becomes extinct. Taxon cycles have been defined mostly for tropical island faunas, examples from continental areas are scarce and similar case studies for plants remain unknown. Most taxon cycles have been identified on the basis of phylogeographic studies, and straightforward empirical evidence from fossils is lacking. Here, empirical fossil evidence is provided for recurrent Eocene to present expansion/contraction cycles in a mangrove taxon (Pelliciera), after a Neotropical-wide study of the available pollen records. This recurrent behavior is compatible with the concept of taxon cycle from biogeographical, chronological and ecological perspectives. The biotic and abiotic drivers potentially involved in the initiation and maintenance of the Pelliciera expansion/contraction cycles are analyzed, and the ecological and evolutionary implications are discussed. Whether this could be a trend toward extinction is considered under the predictions of the taxon cycle theory. The recurrent expansion and contraction cycles identified for Pelliciera have strong potential for being the first empirically and unequivocally documented taxon cycles and likely the only taxon cycles documented to date for plants.","PeriodicalId":501477,"journal":{"name":"bioRxiv - Paleontology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138535403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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