Pub Date : 2025-07-03DOI: 10.1016/j.palwor.2025.200983
Leonardo O. Alvarado-Cárdenas , Naylet K. Centeno-González , C. Sofía Islas-Hernández , Emilio Estrada-Ruiz
The Miocene amber deposit of Chiapas, Mexico, is one of the most important records in the world. It has a high diversity of plant inclusions, particularly the reproductive structures that are seldom preserved. Here we describe a new inclusion of a seed that has a narrowly oblong to linear shape, acuminate chalazal area, longitudinally striated, funicular furrow, micropylar tuft of hairs, all features found in Apocynaceae. Although Mexico is one of the centers of diversity for the family, with an estimated endemism rate of approximately 50%, the fossil record of this family in the country remains limited. Comparison with the extant and fossil seeds did not allow assignment to any known taxa, and therefore a new genus and species, Mesechitespermum endressiorum n. gen. n. sp., is proposed here. This new Miocene record supports the hypothesis that during this time the family was already present in some tropical areas of southeastern Mexico.
墨西哥恰帕斯的中新世琥珀矿床是世界上最重要的记录之一。它具有高度多样性的植物包裹体，特别是很少保存的生殖结构。在这里，我们描述了一种新的种子，它具有狭长圆形到线形，渐尖合点区，纵向条纹，索缕沟，微孔毛丛，在夹竹桃科中发现的所有特征。尽管墨西哥是该家族多样性的中心之一，估计其特有率约为50%，但该家族在该国的化石记录仍然有限。通过与现存种子和化石种子的比较，无法将其归属于任何已知的分类群，因此本文提出了一个新的属和种Mesechitespermum endressiorum n. gen. n. sp.。这个新的中新世记录支持了一种假设，即在此期间，这个家族已经出现在墨西哥东南部的一些热带地区。
{"title":"A new genus and species of Apocynaceae (Gentianales) seed macrofossil from the Early Miocene amber of Simojovel de Allende, Chiapas, Mexico","authors":"Leonardo O. Alvarado-Cárdenas , Naylet K. Centeno-González , C. Sofía Islas-Hernández , Emilio Estrada-Ruiz","doi":"10.1016/j.palwor.2025.200983","DOIUrl":"10.1016/j.palwor.2025.200983","url":null,"abstract":"<div><div>The Miocene amber deposit of Chiapas, Mexico, is one of the most important records in the world. It has a high diversity of plant inclusions, particularly the reproductive structures that are seldom preserved. Here we describe a new inclusion of a seed that has a narrowly oblong to linear shape, acuminate chalazal area, longitudinally striated, funicular furrow, micropylar tuft of hairs, all features found in Apocynaceae. Although Mexico is one of the centers of diversity for the family, with an estimated endemism rate of approximately 50%, the fossil record of this family in the country remains limited. Comparison with the extant and fossil seeds did not allow assignment to any known taxa, and therefore a new genus and species, <em>Mesechitespermum endressiorum</em> n. gen. n. sp., is proposed here. This new Miocene record supports the hypothesis that during this time the family was already present in some tropical areas of southeastern Mexico.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200983"},"PeriodicalIF":1.7,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-03DOI: 10.1016/j.palwor.2025.200982
Hui Min , Rui-Wen Zong , Xun-Lian Wang
The new genus Sericonularia n. gen. is established based on material from the lower Silurian Fentou Formation in Wuhan, China. This genus differs from other conulariids in having extremely thin transverse ribs, thick septa along the corners of the periderm, and flat interspaces. The reproductive mode and the sessile stalk of conulariids have long been controversial. In this study, the holotype of the type species Sericonularia gemmata n. gen. n. sp. provides additional information about possible asexual budding in conulariids; moreover, this specimen offers additional evidence on the structure and morphology of the sessile stalk. We hypothesize that once the buds could live independently, they detached from their parent and then found a suitable substrate; notably, some conulariids used sessile stalks, rather than attachment discs, during their sessile life phase. These stalks appear to have the same structure as the upper periderm. Overall, our observations provide new insights into conulariid affinities and lifestyle.
根据武汉下志留统汾头组的资料，建立了绢虫属（Sericonularia n. gen.）。这个属不同于其他圆锥类在有极薄的横棱，沿周被的角厚的隔，和平的间隙。圆锥植物的生殖方式和无柄茎长期以来一直存在争议。在本研究中，模式种Sericonularia gemmata n. gen. n. sp.的全型为圆锥植物可能的无性出芽提供了额外的信息；此外，该标本为无柄茎的结构和形态提供了额外的证据。我们假设，一旦芽能够独立生活，它们就会从亲本中分离出来，然后找到合适的基质；值得注意的是，一些圆锥植物在其无柄生命阶段使用无柄茎，而不是附着盘。这些茎似乎与上周皮具有相同的结构。总的来说，我们的观察结果提供了新的见解，以了解锥体的亲和力和生活方式。
{"title":"Clonal budding and a sessile stalk in conulariids suggested by a new genus from China","authors":"Hui Min , Rui-Wen Zong , Xun-Lian Wang","doi":"10.1016/j.palwor.2025.200982","DOIUrl":"10.1016/j.palwor.2025.200982","url":null,"abstract":"<div><div>The new genus <em>Sericonularia</em> n. gen. is established based on material from the lower Silurian Fentou Formation in Wuhan, China. This genus differs from other conulariids in having extremely thin transverse ribs, thick septa along the corners of the periderm, and flat interspaces. The reproductive mode and the sessile stalk of conulariids have long been controversial. In this study, the holotype of the type species <em>Sericonularia gemmata</em> n. gen. n. sp. provides additional information about possible asexual budding in conulariids; moreover, this specimen offers additional evidence on the structure and morphology of the sessile stalk. We hypothesize that once the buds could live independently, they detached from their parent and then found a suitable substrate; notably, some conulariids used sessile stalks, rather than attachment discs, during their sessile life phase. These stalks appear to have the same structure as the upper periderm. Overall, our observations provide new insights into conulariid affinities and lifestyle.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200982"},"PeriodicalIF":1.7,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-30DOI: 10.1016/j.palwor.2025.200981
Supanut Bhuttarach , Uthumporn Deesri , Jeremy E. Martin , Sita Manitkoon , Jirasak Charoenmit , Komsorn Lauprasert
Teleosauroids are poorly known from Southeast Asia, with limited records from the Indochina Terrane of Thailand. To better understand their distribution and diversity, we describe new teleosauroid remains from two distinct geological terranes in Thailand. A nearly complete periorbital region and isolated teeth found in association from the Phu Kradung Formation (Upper Jurassic–Lower Cretaceous) of the Indochina Terrane are identified as cf. Indosinosuchus sp. The cranial specimen exhibits periorbital dimensions significantly larger than those of previously described Indosinosuchus specimens, likely representing the largest known individual of the genus and expanding our understanding of morphological diversity within this taxon. The discovery confirms the wide distribution of teleosauroids within the Phu Kradung Formation of the Khorat Plateau during the Late Jurassic to Early Cretaceous. Additionally, a frontal bone, left postorbital, and isolated teeth from the Klong Min Formation (upper Middle–Upper Jurassic) of the Sibumasu Terrane are assigned to Teleosauroidea indet. These remains, morphologically more primitive than Indosinosuchus, represent the first evidence of teleosauroids from southern peninsular Thailand and extend their known temporal range to the Middle Jurassic. Our findings demonstrate that teleosauroids were widely distributed across Thailand’s freshwater environments from the Middle Jurassic through Early Cretaceous, significantly expanding our understanding of their biogeographic distribution in Southeast Asia.
{"title":"New insights into the paleobiogeography of teleosauroid crocodylomorphs in Southeast Asia","authors":"Supanut Bhuttarach , Uthumporn Deesri , Jeremy E. Martin , Sita Manitkoon , Jirasak Charoenmit , Komsorn Lauprasert","doi":"10.1016/j.palwor.2025.200981","DOIUrl":"10.1016/j.palwor.2025.200981","url":null,"abstract":"<div><div>Teleosauroids are poorly known from Southeast Asia, with limited records from the Indochina Terrane of Thailand. To better understand their distribution and diversity, we describe new teleosauroid remains from two distinct geological terranes in Thailand. A nearly complete periorbital region and isolated teeth found in association from the Phu Kradung Formation (Upper Jurassic–Lower Cretaceous) of the Indochina Terrane are identified as cf. <em>Indosinosuchus</em> sp. The cranial specimen exhibits periorbital dimensions significantly larger than those of previously described <em>Indosinosuchus</em> specimens, likely representing the largest known individual of the genus and expanding our understanding of morphological diversity within this taxon. The discovery confirms the wide distribution of teleosauroids within the Phu Kradung Formation of the Khorat Plateau during the Late Jurassic to Early Cretaceous. Additionally, a frontal bone, left postorbital, and isolated teeth from the Klong Min Formation (upper Middle–Upper Jurassic) of the Sibumasu Terrane are assigned to Teleosauroidea indet. These remains, morphologically more primitive than <em>Indosinosuchus</em>, represent the first evidence of teleosauroids from southern peninsular Thailand and extend their known temporal range to the Middle Jurassic. Our findings demonstrate that teleosauroids were widely distributed across Thailand’s freshwater environments from the Middle Jurassic through Early Cretaceous, significantly expanding our understanding of their biogeographic distribution in Southeast Asia.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200981"},"PeriodicalIF":1.7,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-28DOI: 10.1016/j.palwor.2025.200980
Salma Soussi , Fares Khemiri , Amina Mabrouk El Asmi , Moez Ben Fadhel , Habib Troudi , Khaled El Asmi , Gonzalo Márquez Martinez
An integrated analysis of multiple geochemical proxies, including δ13Corg, total organic carbon (TOC), trace elements, and chemical gamma ray, coupled with a microfacies study and an age calibration using planktonic foraminiferal markers, was conducted at the Ain Asker section in northern Tunisia. This study provides significant insights into the depositional and paleoenvironmental dynamics of the mid-Cretaceous.
The carbon isotopic excursions observed at the Ain Asker section reflect a notable increase in the burial rate of marine organic carbon, specifically confined to the middle part of the Microhedbergella rischi biozone. TOC values recorded from the F2-ASK unit reach up to 2.3% combined with a δ13Corg values reaching -24.49‰, suggesting substantial accumulation of decayed marine organic matter. Although full anoxic conditions were not prevalent during deposition, evidence of oxygen-depleted bottom waters is clearly supported by the distribution patterns of redox-sensitive trace elements, such as vanadium and nickel. These findings underscore the role of partial oxygen restriction in facilitating organic matter preservation.
The enhanced burial of organic carbon is attributed to increased nutrient influx, likely driven by global sea-level transgressions and heightened surface productivity. These processes created favorable conditions for organic matter production and preservation. The integration of these sedimentological and geochemical findings with comparative records from Europe (France and Italy), China, and Mexico enables reliable correlation with the Paquier black shale level, a hallmark of OAE1b.
The Ain Asker section, through its detailed geochemical and isotopic signatures, emerges as a critical reference section for unraveling mid-Cretaceous anoxia dynamics within the southern Tethyan Realm. Its study enhances our understanding of the interplay between global paleoceanographic events and local depositional processes, shedding light on the mechanisms of organic carbon burial during a pivotal period in Earth’s history.
{"title":"Chemostratigraphy of Albian deposits in northern Tunisia: Identification of early Albian Oceanic Anoxic Event in the southern Tethys","authors":"Salma Soussi , Fares Khemiri , Amina Mabrouk El Asmi , Moez Ben Fadhel , Habib Troudi , Khaled El Asmi , Gonzalo Márquez Martinez","doi":"10.1016/j.palwor.2025.200980","DOIUrl":"10.1016/j.palwor.2025.200980","url":null,"abstract":"<div><div>An integrated analysis of multiple geochemical proxies, including δ<sup>13</sup>C<sub>org</sub>, total organic carbon (TOC), trace elements, and chemical gamma ray, coupled with a microfacies study and an age calibration using planktonic foraminiferal markers, was conducted at the Ain Asker section in northern Tunisia. This study provides significant insights into the depositional and paleoenvironmental dynamics of the mid-Cretaceous.</div><div>The carbon isotopic excursions observed at the Ain Asker section reflect a notable increase in the burial rate of marine organic carbon, specifically confined to the middle part of the <em>Microhedbergella rischi</em> biozone. TOC values recorded from the F2-ASK unit reach up to 2.3% combined with a δ<sup>13</sup>C<sub>org</sub> values reaching -24.49‰, suggesting substantial accumulation of decayed marine organic matter. Although full anoxic conditions were not prevalent during deposition, evidence of oxygen-depleted bottom waters is clearly supported by the distribution patterns of redox-sensitive trace elements, such as vanadium and nickel. These findings underscore the role of partial oxygen restriction in facilitating organic matter preservation.</div><div>The enhanced burial of organic carbon is attributed to increased nutrient influx, likely driven by global sea-level transgressions and heightened surface productivity. These processes created favorable conditions for organic matter production and preservation. The integration of these sedimentological and geochemical findings with comparative records from Europe (France and Italy), China, and Mexico enables reliable correlation with the Paquier black shale level, a hallmark of OAE1b.</div><div>The Ain Asker section, through its detailed geochemical and isotopic signatures, emerges as a critical reference section for unraveling mid-Cretaceous anoxia dynamics within the southern Tethyan Realm. Its study enhances our understanding of the interplay between global paleoceanographic events and local depositional processes, shedding light on the mechanisms of organic carbon burial during a pivotal period in Earth’s history.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200980"},"PeriodicalIF":1.7,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145128373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This is the first comprehensive systematic study of the Middle Jurassic scleractinian corals from the Qiangtang block, based on 225 fossil coral specimens collected from the Buqu Formation in the Biluocuo area of northern Xizang (Tibet). Three species of three genera are identified: Montlivaltia zangbeiensis, Pseudocoenia slovenica, and Kobyastraea coquandi. The assemblage is dominated by solitary Montlivaltia (92.44%), with significantly fewer compound colonies of Pseudocoenia (4.89%) and Kobyastraea (2.67%). Comparative analysis reveals that the Qiangtang coral fauna shows strong affinities with contemporaneous Tethyan assemblages, particularly showing the closest similarities to coral communities from East-Central Iran. These findings provide compelling evidence for a close palaeobiogeographic connection between the Qiangtang block and the central Tethyan region during the Middle Jurassic.
{"title":"Scleractinian corals from the Middle Jurassic Buqu Formation, Qiangtang block and their palaeogeographic implications","authors":"Xiu-Ping Zhu , Kun Liang , Wei-Hua Liao , Jia-Run Yin , Xin Rao , Yi-Chun Zhang","doi":"10.1016/j.palwor.2025.200978","DOIUrl":"10.1016/j.palwor.2025.200978","url":null,"abstract":"<div><div>This is the first comprehensive systematic study of the Middle Jurassic scleractinian corals from the Qiangtang block, based on 225 fossil coral specimens collected from the Buqu Formation in the Biluocuo area of northern Xizang (Tibet). Three species of three genera are identified: <em>Montlivaltia zangbeiensis</em>, <em>Pseudocoenia slovenica</em>, and <em>Kobyastraea coquandi</em>. The assemblage is dominated by solitary <em>Montlivaltia</em> (92.44%), with significantly fewer compound colonies of <em>Pseudocoenia</em> (4.89%) and <em>Kobyastraea</em> (2.67%). Comparative analysis reveals that the Qiangtang coral fauna shows strong affinities with contemporaneous Tethyan assemblages, particularly showing the closest similarities to coral communities from East-Central Iran. These findings provide compelling evidence for a close palaeobiogeographic connection between the Qiangtang block and the central Tethyan region during the Middle Jurassic.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"35 1","pages":"Article 200978"},"PeriodicalIF":1.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-26DOI: 10.1016/j.palwor.2025.200979
Shu-Ran Tang , Qi-Jia Li , Hui Jia , Jian-Hua Jin , Cheng Quan
Plant development is highly influenced by ecological conditions, with different latitudes hosting vegetation with distinct component and ecological strategies. However, the ecological strategies of low-latitude plants in deep time remain poorly understood. In this study, we examine well-preserved fossil leaves from the upper Miocene of Beihai, low-latitude China, and describe three species of Calophyllum (Calophyllaceae) based on morphological and anatomical characteristics. Using leaf economic concepts, the ecological strategy of Calophyllum during the late Miocene is also evaluated. Our results suggest that all the three fossil species have leaf mass per area (LMA) higher than their nearest living relatives. It appears that the longer leaf lifespan driven by longer growing season likely contributed to the high LMA and hence the slow-return ecological strategy of Calophyllum in the late Miocene hereof. This study highlights the leaf lifespan in regulation of plant ecological strategies and provides insights into the palaeoecology of low-latitude vegetation during the late Miocene.
{"title":"Calophyllum (Calophyllaceae) with high leaf mass per area from the upper Miocene of Beihai, low-latitude China","authors":"Shu-Ran Tang , Qi-Jia Li , Hui Jia , Jian-Hua Jin , Cheng Quan","doi":"10.1016/j.palwor.2025.200979","DOIUrl":"10.1016/j.palwor.2025.200979","url":null,"abstract":"<div><div>Plant development is highly influenced by ecological conditions, with different latitudes hosting vegetation with distinct component and ecological strategies. However, the ecological strategies of low-latitude plants in deep time remain poorly understood. In this study, we examine well-preserved fossil leaves from the upper Miocene of Beihai, low-latitude China, and describe three species of <em>Calophyllum</em> (Calophyllaceae) based on morphological and anatomical characteristics. Using leaf economic concepts, the ecological strategy of <em>Calophyllum</em> during the late Miocene is also evaluated. Our results suggest that all the three fossil species have leaf mass per area (LMA) higher than their nearest living relatives. It appears that the longer leaf lifespan driven by longer growing season likely contributed to the high LMA and hence the slow-return ecological strategy of <em>Calophyllum</em> in the late Miocene hereof. This study highlights the leaf lifespan in regulation of plant ecological strategies and provides insights into the palaeoecology of low-latitude vegetation during the late Miocene.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200979"},"PeriodicalIF":1.7,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-19DOI: 10.1016/j.palwor.2025.200977
Yun-Xia Jia , Wen-Chao Zhang , Li-Jun Tian , Zhi-Lin He , Zhao Wang , Qing-Chun Tian
The modern Asian environment comprises monsoon-dominated East Asia and the arid Asian interior. However, when and how the modern climatic environment of Asia evolved remains controversial. Quantitative and spatio-temporal paleovegetation reconstructions are crucial for addressing this issue. We compiled 10 well-dated pollen records across the northeastern Tibetan Plateau, stretching from western China into eastern China. We used the biomization method to generate a set of biome scores and landscape openness spanning the interval from the Eocene to Recent. Biome reconstructions reveal that five dominant vegetation types have attained the highest scores since ∼42 Ma, namely warm mixed forest, temperate deciduous forest, cool mixed forest, steppe, and desert. Spatially, our results reveal that the climate was predominantly wetter in the west than in the east during the Paleogene, as evidenced by the higher values of landscape openness in the west. Since ∼24 Ma this climate configuration has reversed. Temporally, our results reveal wet-dry climatic fluctuations during the Paleogene, as evidenced by the coexistence of open vegetation and forest vegetation. Then, our results reveal a reorganization of the climatic environment since ∼24 Ma, as evidenced by the presence of forest vegetation types in the east and decreasing trend of landscape openness in the west. Subsequently, our results reveal region-wide aridification since ∼8 Ma, as evidenced by the negative values of landscape openness in many regions. Together with previous paleoclimate records, we infer that the retreat of the Paratethys Sea was responsible for wet-dry fluctuations during the Paleogene. We also infer that the uplift of Central Xizang (Tibet) triggered the permanent reorganization of the Asian environment at the Oligocene/Miocene transition, and that global cooling promoted the subsequent aridification trend.
{"title":"Spatiotemporal pattern of vegetation evolution in northeastern Tibetan Plateau during the Cenozoic and its climatic significance","authors":"Yun-Xia Jia , Wen-Chao Zhang , Li-Jun Tian , Zhi-Lin He , Zhao Wang , Qing-Chun Tian","doi":"10.1016/j.palwor.2025.200977","DOIUrl":"10.1016/j.palwor.2025.200977","url":null,"abstract":"<div><div>The modern Asian environment comprises monsoon-dominated East Asia and the arid Asian interior. However, when and how the modern climatic environment of Asia evolved remains controversial. Quantitative and spatio-temporal paleovegetation reconstructions are crucial for addressing this issue. We compiled 10 well-dated pollen records across the northeastern Tibetan Plateau, stretching from western China into eastern China. We used the biomization method to generate a set of biome scores and landscape openness spanning the interval from the Eocene to Recent. Biome reconstructions reveal that five dominant vegetation types have attained the highest scores since ∼42 Ma, namely warm mixed forest, temperate deciduous forest, cool mixed forest, steppe, and desert. Spatially, our results reveal that the climate was predominantly wetter in the west than in the east during the Paleogene, as evidenced by the higher values of landscape openness in the west. Since ∼24 Ma this climate configuration has reversed. Temporally, our results reveal wet-dry climatic fluctuations during the Paleogene, as evidenced by the coexistence of open vegetation and forest vegetation. Then, our results reveal a reorganization of the climatic environment since ∼24 Ma, as evidenced by the presence of forest vegetation types in the east and decreasing trend of landscape openness in the west. Subsequently, our results reveal region-wide aridification since ∼8 Ma, as evidenced by the negative values of landscape openness in many regions. Together with previous paleoclimate records, we infer that the retreat of the Paratethys Sea was responsible for wet-dry fluctuations during the Paleogene. We also infer that the uplift of Central Xizang (Tibet) triggered the permanent reorganization of the Asian environment at the Oligocene/Miocene transition, and that global cooling promoted the subsequent aridification trend.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 6","pages":"Article 200977"},"PeriodicalIF":1.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-13DOI: 10.1016/j.palwor.2025.200970
Şükrü Acar, Alper Bozkurt
The Priabonian (Eocene) shallow-water carbonates of the Malatya region (eastern Türkiye) contain rich benthic foraminiferal assemblages. A new calcarinid genus (Hereceina n. gen.) with its type species (Hereceina spinigera n. gen. n. sp.) and two Borelis species (Borelis dizerae n. sp. and Borelis sozerii n. sp.) are systematically described from these deposits. A late Priabonian age, corresponding to SBZ 20, is assigned to the new taxa based on the co-occurrence of biostratigraphic markers such as Heterostegina gracilis and Spiroclypeus carpaticus. Based on microfacies studies, Hereceina spinigera n. gen. n. sp. is documented from inner to proximal middle ramp environments that were influenced by wave and current action. The introduction of these new Borelis species with Y-shaped septula from the upper Priabonian of the region provides new insights into the evolutionary history of the genus. This study highlights the significant potential of the new taxa that appeared during the Eocene–Oligocene marine extinctions to serve as valuable biostratigraphic markers at Tethyan localities.
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Pub Date : 2025-06-09DOI: 10.1016/j.palwor.2025.200969
Zhao-Yang Yi , Zhen Yan , Xin Wei , Kai Wang , Bing Shen , Jian-Bo Liu
The relationship between microbial calcification and atmospheric CO2 levels is a critical aspect of Earth’s biogeochemical evolution. This study presents the first detailed investigation of micro- and mesoscopic features of stromatolites from the 2.1 Ga Dashiling Formation of the Hutuo Group in Wutai area, North China, one of the best preserved microbialites during the Great Oxidation Event (GOE). The study identifies three types of microclots (microclots-1, -2 and -3) as key contributors to the formation of stromatolitic laminae in the Dashiling Formation. These microclots form layered, meshed, and dendritic microclotted laminae, characterized by alternation of light and dark laminae, with lighter laminae being sparsely distributed and darker laminae densely distributed. These alternations reflect the periodic growth and decay of microbial communities in response to dynamic environmental changes. The microclots and microclotted laminae in the Dashiling Formation exhibit evidence for microbial calcification, suggesting that atmospheric CO2 levels during the early Paleoproterozoic may have been lower than previously estimated. Previous studies have proposed that microbial calcification occurs extensively only when atmospheric CO2 declines to ∼10 times the present atmospheric level. The well-preserved microclots and calcified microbial structures in the Dashiling Formation suggest that atmospheric CO2 levels during the GOE may have approached or fallen below this threshold. While increased atmospheric O2 levels during the GOE may have influenced microbial calcification, our results indicate that declining CO2 levels played a more direct role in facilitating carbonate precipitation. These findings refine the understanding of the interplay between microbial activities, atmospheric CO2 decline, and carbonate saturation during the GOE, offering new insights into early Earth’s carbon cycle dynamics.
{"title":"Microclots in early Paleoproterozoic stromatolites from Dashiling Formation, Wutai, North China: Implications for microbial calcification and atmospheric CO2 levels during Great Oxidation Event","authors":"Zhao-Yang Yi , Zhen Yan , Xin Wei , Kai Wang , Bing Shen , Jian-Bo Liu","doi":"10.1016/j.palwor.2025.200969","DOIUrl":"10.1016/j.palwor.2025.200969","url":null,"abstract":"<div><div>The relationship between microbial calcification and atmospheric CO<sub>2</sub> levels is a critical aspect of Earth’s biogeochemical evolution. This study presents the first detailed investigation of micro- and mesoscopic features of stromatolites from the 2.1 Ga Dashiling Formation of the Hutuo Group in Wutai area, North China, one of the best preserved microbialites during the Great Oxidation Event (GOE). The study identifies three types of microclots (microclots-1, -2 and -3) as key contributors to the formation of stromatolitic laminae in the Dashiling Formation. These microclots form layered, meshed, and dendritic microclotted laminae, characterized by alternation of light and dark laminae, with lighter laminae being sparsely distributed and darker laminae densely distributed. These alternations reflect the periodic growth and decay of microbial communities in response to dynamic environmental changes. The microclots and microclotted laminae in the Dashiling Formation exhibit evidence for microbial calcification, suggesting that atmospheric CO<sub>2</sub> levels during the early Paleoproterozoic may have been lower than previously estimated. Previous studies have proposed that microbial calcification occurs extensively only when atmospheric CO<sub>2</sub> declines to ∼10 times the present atmospheric level. The well-preserved microclots and calcified microbial structures in the Dashiling Formation suggest that atmospheric CO<sub>2</sub> levels during the GOE may have approached or fallen below this threshold. While increased atmospheric O<sub>2</sub> levels during the GOE may have influenced microbial calcification, our results indicate that declining CO<sub>2</sub> levels played a more direct role in facilitating carbonate precipitation. These findings refine the understanding of the interplay between microbial activities, atmospheric CO<sub>2</sub> decline, and carbonate saturation during the GOE, offering new insights into early Earth’s carbon cycle dynamics.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 5","pages":"Article 200969"},"PeriodicalIF":1.7,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-06DOI: 10.1016/j.palwor.2025.200968
Zainab M. El-Noamani, Wagieh E. El-Saadawi, Marwah M. Kamal El-Din, Nermeen A. Ziada
This study examines 12 well-preserved specimens collected from the Miocene Moghra and Gebel Khashab formations at six sites in the northern part of the Western Desert of Egypt. The results reveal distinct anatomical features for each of the four morphospecies (namely Palmoxylon aschersoni Schenk, P. cf. aschersoni Schenk, P. lacunosum (Unger) Felix, and P. libycum (Stenzel) Kräusel), confirming their identification and classification within the subfamily Coryphoideae. The paleoclimatic conditions for each species are interpreted based on key ecologically-based anatomical traits, such as the number of metaxylem elements and the nature of ground tissue. These findings indicate that the four recorded species reflect different paleoenvironments and depositional conditions, suggesting that they were transported by water from their original growth sites to their current locations, resulting in an intermingling of forest forms in the northern Western Desert. An overview of the fossil record of the subfamily Coryphoideae in Africa is also provided.
这项研究检查了在埃及西部沙漠北部的六个地点从中新世Moghra和Gebel Khashab地层收集的12个保存完好的标本。结果揭示了四个形态种(Palmoxylon aschersoni Schenk， P. cf. aschersoni Schenk， P. lacunosum （Unger) Felix和P. libycum (Stenzel) Kräusel）各自的解剖特征，证实了它们在蕨亚科中的鉴定和分类。每个物种的古气候条件都是基于关键的生态解剖学特征来解释的，比如韧皮部元素的数量和地面组织的性质。这些发现表明，这四种记录物种反映了不同的古环境和沉积条件，表明它们被水从原始生长地点转移到现在的位置，导致西部沙漠北部森林形式的混合。本文还概述了非洲斑蝶亚科的化石记录。
{"title":"Anatomy and paleoclimatic implications of Cenozoic Coryphoideae palm wood species in Egypt","authors":"Zainab M. El-Noamani, Wagieh E. El-Saadawi, Marwah M. Kamal El-Din, Nermeen A. Ziada","doi":"10.1016/j.palwor.2025.200968","DOIUrl":"10.1016/j.palwor.2025.200968","url":null,"abstract":"<div><div>This study examines 12 well-preserved specimens collected from the Miocene Moghra and Gebel Khashab formations at six sites in the northern part of the Western Desert of Egypt. The results reveal distinct anatomical features for each of the four morphospecies (namely <em>Palmoxylon aschersoni</em> Schenk, <em>P</em>. cf. <em>aschersoni</em> Schenk, <em>P</em>. <em>lacunosum</em> (Unger) Felix, and <em>P</em>. <em>libycum</em> (Stenzel) Kräusel), confirming their identification and classification within the subfamily Coryphoideae. The paleoclimatic conditions for each species are interpreted based on key ecologically-based anatomical traits, such as the number of metaxylem elements and the nature of ground tissue. These findings indicate that the four recorded species reflect different paleoenvironments and depositional conditions, suggesting that they were transported by water from their original growth sites to their current locations, resulting in an intermingling of forest forms in the northern Western Desert. An overview of the fossil record of the subfamily Coryphoideae in Africa is also provided.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 5","pages":"Article 200968"},"PeriodicalIF":1.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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