Studying the temporal and spatial distributions and dynamics of fossils is crucial for understanding macroevolution processes in geological history. Biodiversity data provide an overview of faunal changes during extinction events, but it cannot differentiate the impact of extinction events on different species. Biogeographic study complements these data by offering more detailed insights into evolutionary patterns. A dataset of 704 graptolite occurrence records for the Late Ordovician Mass Extinction (LOME) was compiled from 60 localities in South China. The geographic distributions of 26 species across four graptolite biochrons (from late Katian to Hirnantian) were quantitatively reconstructed using ArcGIS. Two types of geographic range indexes, including convex hull areas and maximum distribution distances, were calculated for each species in each time slice. Based on the variations in the geographic ranges, the graptolites can be divided into three types. The geographic ranges of the first type shrank before the extinction, that of the second type expanded before the extinction but shrank during the extinction, and that of the third type expanded during the extinction. The first two types include Diplograptina species; and the third of Neograptina species. The study revealed that the extinction event affected all diplograptid graptolite species, as evidenced by the rate of decrease in geographic ranges. Interestingly, the impact of the major extinction appeared to be uniform across all graptolite species, irrespective of their initial geographic range size. The distribution centers of the graptolite species remained relatively stable and predominantly surrounded the center of the sea during the LOME. The substantial reduction in the geographic ranges of diplograptid species might be due to the global factors rather than local sea level decline.
{"title":"Biogeographic dynamics of graptolites during the Late Ordovician Mass Extinction in South China","authors":"Lin-Na Zhang, Sha-Sha Sun, Zong-Yuan Sun, Ming-Feng Lu, Qing Chen","doi":"10.1016/j.palwor.2024.06.008","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.06.008","url":null,"abstract":"Studying the temporal and spatial distributions and dynamics of fossils is crucial for understanding macroevolution processes in geological history. Biodiversity data provide an overview of faunal changes during extinction events, but it cannot differentiate the impact of extinction events on different species. Biogeographic study complements these data by offering more detailed insights into evolutionary patterns. A dataset of 704 graptolite occurrence records for the Late Ordovician Mass Extinction (LOME) was compiled from 60 localities in South China. The geographic distributions of 26 species across four graptolite biochrons (from late Katian to Hirnantian) were quantitatively reconstructed using ArcGIS. Two types of geographic range indexes, including convex hull areas and maximum distribution distances, were calculated for each species in each time slice. Based on the variations in the geographic ranges, the graptolites can be divided into three types. The geographic ranges of the first type shrank before the extinction, that of the second type expanded before the extinction but shrank during the extinction, and that of the third type expanded during the extinction. The first two types include Diplograptina species; and the third of Neograptina species. The study revealed that the extinction event affected all diplograptid graptolite species, as evidenced by the rate of decrease in geographic ranges. Interestingly, the impact of the major extinction appeared to be uniform across all graptolite species, irrespective of their initial geographic range size. The distribution centers of the graptolite species remained relatively stable and predominantly surrounded the center of the sea during the LOME. The substantial reduction in the geographic ranges of diplograptid species might be due to the global factors rather than local sea level decline.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782008","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.06.006
Esraa S. Ibrahim, Magdy M. El Hedeny, Ahmed M. El-Sabbagh, Gebely A. Abu El-Kheir, Alaa G. Osman, Aldoushy Mahdy, Enas A. Ahmed
The present study examines the basilosaurid whale bone specimens collected from the Sandouk El-Borneta section, Wadi El-Hitan (Valley of Whales), Fayum, Egypt. These specimens are embedded in highly fossiliferous calcareous sandstones of the middle Eocene Gehannam and the upper Eocene Birket Qarun formations. These whale bones display some post-mortem alterations, representing good signs of at least three distinct stages in what is called the whale fall. The co-occurrence of shark, ray, and crocodile fossil specimens with the examined whale bones may indicate the first mobile-scavenger stage. Borings of the siboglinid polychaete genus represent the most common worm type that deeply bioeroded the whale bones, contributing to their rapid degradation, and representing the enrichment-opportunist stage. These fossil traces of the bone-eating worm represent the first record in the Eocene Epoch regionally and inter-regionally, filling the gap between the Late Cretaceous and the Oligocene occurrences. Subsequently, the studied whale bones served as hard substrates for some calcareous tube-dwelling encrusting polychaetes, balanoid barnacles, sheet‐like cheilostome bryozoans, and scleractinian corals. Furthermore, a bioerosion structure produced by polychaete annelids was also observed. The presence of these sclerobionts assemblage confirms the well-developed final reef stage with prolonged exposure and colonisation of these whale bones prior to final burial. Based on the recorded post-mortem alterations, together with other sedimentological and palaeontological data, the studied whale bones were deposited in a shallow open marine bay to sheltered gulf environments, which were characterised by low depositional energy, low to moderate rate of sedimentation, and high surface water productivity.
{"title":"Shallow-water whale-fall communities: Evidence from the middle–late Eocene basilosaurid whale bones, Wadi El-Hitan, Fayum, Egypt","authors":"Esraa S. Ibrahim, Magdy M. El Hedeny, Ahmed M. El-Sabbagh, Gebely A. Abu El-Kheir, Alaa G. Osman, Aldoushy Mahdy, Enas A. Ahmed","doi":"10.1016/j.palwor.2024.06.006","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.06.006","url":null,"abstract":"The present study examines the basilosaurid whale bone specimens collected from the Sandouk El-Borneta section, Wadi El-Hitan (Valley of Whales), Fayum, Egypt. These specimens are embedded in highly fossiliferous calcareous sandstones of the middle Eocene Gehannam and the upper Eocene Birket Qarun formations. These whale bones display some post-mortem alterations, representing good signs of at least three distinct stages in what is called the whale fall. The co-occurrence of shark, ray, and crocodile fossil specimens with the examined whale bones may indicate the first mobile-scavenger stage. Borings of the siboglinid polychaete genus represent the most common worm type that deeply bioeroded the whale bones, contributing to their rapid degradation, and representing the enrichment-opportunist stage. These fossil traces of the bone-eating worm represent the first record in the Eocene Epoch regionally and inter-regionally, filling the gap between the Late Cretaceous and the Oligocene occurrences. Subsequently, the studied whale bones served as hard substrates for some calcareous tube-dwelling encrusting polychaetes, balanoid barnacles, sheet‐like cheilostome bryozoans, and scleractinian corals. Furthermore, a bioerosion structure produced by polychaete annelids was also observed. The presence of these sclerobionts assemblage confirms the well-developed final reef stage with prolonged exposure and colonisation of these whale bones prior to final burial. Based on the recorded post-mortem alterations, together with other sedimentological and palaeontological data, the studied whale bones were deposited in a shallow open marine bay to sheltered gulf environments, which were characterised by low depositional energy, low to moderate rate of sedimentation, and high surface water productivity.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782016","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.06.005
Ünal Akkemik, Özlem Toprak, Dimitra Mantzouka
The middle Eocene climate optimum, a crucial greenhouse event in Earth’s life history, occurred approximately 40 Ma. Fossil wood identifications of middle Eocene age reveal important evidence for the terrestrial tropical/subtropical conditions during this period. The purpose of the present study is to identify new fossil woods from the middle Eocene of north-central Turkey and to evaluate the paleoclimate and paleovegetational history of the north-central Turkey based on new records. Seven fossil woods were collected from the middle Eocene Göynücek Volcanics of the Çekerek Formation (Sarıkaya village, close to Çekerek, Yozgat). Two new species Akkemik and Mantzouka, n. sp., and Akkemik and Mantzouka, n. sp., are described, together with two more coniferous species cf. () and cf. . Although dealing with a rather low number of fossil wood findings, indistinct boundaries of the tree rings, low xeromorphy ratios and high conductivity values in these two new fossil angiosperm species and less visible and indistinct boundaries in the two fossil coniferous species may reflect the warm, humid tropical conditions of the middle Eocene of north-central Turkey. The results are consistent with our former paleoecological evaluation based on the fossil woods including Akkemik and Mantzouka in from the same geological unit and from the same area.
{"title":"New fossil woods from the middle Eocene climate optimum of north-central Turkey","authors":"Ünal Akkemik, Özlem Toprak, Dimitra Mantzouka","doi":"10.1016/j.palwor.2024.06.005","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.06.005","url":null,"abstract":"The middle Eocene climate optimum, a crucial greenhouse event in Earth’s life history, occurred approximately 40 Ma. Fossil wood identifications of middle Eocene age reveal important evidence for the terrestrial tropical/subtropical conditions during this period. The purpose of the present study is to identify new fossil woods from the middle Eocene of north-central Turkey and to evaluate the paleoclimate and paleovegetational history of the north-central Turkey based on new records. Seven fossil woods were collected from the middle Eocene Göynücek Volcanics of the Çekerek Formation (Sarıkaya village, close to Çekerek, Yozgat). Two new species Akkemik and Mantzouka, n. sp., and Akkemik and Mantzouka, n. sp., are described, together with two more coniferous species cf. () and cf. . Although dealing with a rather low number of fossil wood findings, indistinct boundaries of the tree rings, low xeromorphy ratios and high conductivity values in these two new fossil angiosperm species and less visible and indistinct boundaries in the two fossil coniferous species may reflect the warm, humid tropical conditions of the middle Eocene of north-central Turkey. The results are consistent with our former paleoecological evaluation based on the fossil woods including Akkemik and Mantzouka in from the same geological unit and from the same area.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781745","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.05.005
Olga Alcântara Barros, Paulo Victor de Oliveira, Antônio Álamo Feitosa Saraiva
The preservation of shrimp in the fossil record is difficult due to their rapid decomposition. In this study, we provide new taxonomic insights into from the Lower Cretaceous Romualdo Formation in the Araripe Basin, northeastern Brazil. A comprehensive taxonomic review, including a more meticulous preparation of the holotype and additional fossil material, enabled the disclosure of previously unknown anatomical features, reaffirming its classification within the family Palaemonidae.
{"title":"New data and redescription of Kellnerius jamacaruensis Santana et al., 2013, a Palaemonidae shrimp from the Araripe Basin in northeastern Brazil","authors":"Olga Alcântara Barros, Paulo Victor de Oliveira, Antônio Álamo Feitosa Saraiva","doi":"10.1016/j.palwor.2024.05.005","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.005","url":null,"abstract":"The preservation of shrimp in the fossil record is difficult due to their rapid decomposition. In this study, we provide new taxonomic insights into from the Lower Cretaceous Romualdo Formation in the Araripe Basin, northeastern Brazil. A comprehensive taxonomic review, including a more meticulous preparation of the holotype and additional fossil material, enabled the disclosure of previously unknown anatomical features, reaffirming its classification within the family Palaemonidae.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781738","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.05.007
Aleksandr S. Bakaev
The Kuznetsk Basin in Siberia (Russia) is an important area for the study of the continental biota of late Permian to Early Triassic in continuous sections. This study presents a taxonomic description of ray-finned fishes (other fish remains are absent at the section) from the Permian–Triassic boundary section at Babiy Kamen. The new material was collected, bed by bed, during geological and paleontological excavations of coastal-floodplain, shallow-basin deposits of the Tailugan and Maltseva formations. The poorly preserved but diverse ichthyofaunal fossils of the Tailugan Formation consists predominantly of typical Late Paleozoic “palaeoniscoid” fishes (Eurynotoidiidae, Varialepididae, etc.). The earliest known Triassic (Induan) Kedrovo Member of the Maltseva Formation contained a less diverse but well preserved ichthyofaunal fossils including “palaeoniscoid” fishes ( and ). The same species were described earlier from the Induan of the Tunguska Basin. The ichthyofauna of the Early Triassic (Olenekian) Ryaboy Kamen Member of the Maltseva Formation consists of typical Triassic stem-neopterygian (, and ) fishes. The same fishes have been described earlier from the Olenekian of Tunguska Basin. The composition of the ichthyofauna completely changed twice — at the Permian–Triassic and the Induan–Olenekian boundaries.
俄罗斯西伯利亚库兹涅茨克盆地是研究二叠纪晚期至三叠纪早期大陆生物群连续剖面的重要地区。本研究介绍了巴比卡门二叠纪-三叠纪边界剖面中鳐鱼类（该剖面没有其他鱼类遗骸）的分类学描述。新材料是在对泰卢根地层和马尔采娃地层的沿海洪积平原浅盆地沉积物进行地质和古生物发掘时逐层采集的。泰卢根地层的鱼类化石保存较差，但种类繁多，主要由典型的晚古生代 "古类 "鱼类（Eurynotoidiidae、Varialepididae 等）组成。马尔采瓦地层中已知最早的三叠纪（印支期）Kedrovo 成员包含种类较少但保存完好的鱼类化石，其中包括 "古类 "鱼类（和）。早些时候，通古斯卡盆地的印端也曾描述过相同的物种。马尔采瓦地层早三叠世（奥利尼克期）Ryaboy Kamen 组的鱼类化石包括典型的三叠世茎新目鱼类（、和）。早先在通古斯卡盆地的奥连纪中也曾描述过同样的鱼类。鱼类动物群的组成在二叠纪-三叠纪和印支-奥勒涅基纪的交界处发生了两次彻底的变化。
{"title":"Actinopterygians from the continental Permian–Triassic boundary section at Babiy Kamen (Kuznetsk Basin, Siberia, Russia)","authors":"Aleksandr S. Bakaev","doi":"10.1016/j.palwor.2024.05.007","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.007","url":null,"abstract":"The Kuznetsk Basin in Siberia (Russia) is an important area for the study of the continental biota of late Permian to Early Triassic in continuous sections. This study presents a taxonomic description of ray-finned fishes (other fish remains are absent at the section) from the Permian–Triassic boundary section at Babiy Kamen. The new material was collected, bed by bed, during geological and paleontological excavations of coastal-floodplain, shallow-basin deposits of the Tailugan and Maltseva formations. The poorly preserved but diverse ichthyofaunal fossils of the Tailugan Formation consists predominantly of typical Late Paleozoic “palaeoniscoid” fishes (Eurynotoidiidae, Varialepididae, etc.). The earliest known Triassic (Induan) Kedrovo Member of the Maltseva Formation contained a less diverse but well preserved ichthyofaunal fossils including “palaeoniscoid” fishes ( and ). The same species were described earlier from the Induan of the Tunguska Basin. The ichthyofauna of the Early Triassic (Olenekian) Ryaboy Kamen Member of the Maltseva Formation consists of typical Triassic stem-neopterygian (, and ) fishes. The same fishes have been described earlier from the Olenekian of Tunguska Basin. The composition of the ichthyofauna completely changed twice — at the Permian–Triassic and the Induan–Olenekian boundaries.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782015","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.06.001
Yan-Bin Zhu, Ya Li, Jian-Ping Zhang, Yong-Dong Wang, Nikolaos Zouros
a Carrière is commonly known as Douglas-fir, a minor genus attributed to Pinaceae. Four extant species are included in this genus, with dispersed distribution in East Asia and western North America. possesses a number of fossil records of needled leaves, seed cones, and seeds. Nevertheless, few reliable fossil wood of this genus has been specifically investigated. Here, we describe some anatomically well-preserved petrified fossil wood from the lower Miocene of Lesvos Island, Greece, as n. sp. The studied fossil wood remains are characterized by the presence of normal axial and radial resin canals, piceoid cross-field pitting, along with distinctive helical thickenings in cell walls consistent with . The present fossil conifer further enriches the species diversity of the Miocene Petrified Forest in Lesvos. The first report of from the southern Europe in this study extends the tempo-spatial distribution patterns of and contributes to further understanding of its origin and evolutionary history. The occurrence of . fossil wood, as well as other palaeontological macrofloral composition evidence, indicates a humid warm temperate to subtropical climatic condition during the early Miocene within the Lesvos, which differs significantly from the current Mediterranean climate.
a Carrière 通常被称为花旗松，是松科的一个小属。该属有四个现存物种，分散分布在东亚和北美西部。 该属拥有许多针叶、球果和种子的化石记录。然而，很少有人对该属的可靠木材化石进行过专门调查。在这里，我们描述了希腊莱斯沃斯岛下中新世的一些解剖学上保存完好的石化木化石。所研究的木化石残骸的特征是存在正常的轴向和径向树脂管、类皮质横场点蚀，以及细胞壁上明显的螺旋状增厚，与......一致。目前发现的针叶树化石进一步丰富了莱斯沃斯中新世石化森林的物种多样性。这项研究首次报告了来自南欧的化石，扩展了化石的时间-空间分布模式，有助于进一步了解其起源和进化历史。......木化石的出现以及其他古生物学宏观植物成分证据表明，莱斯沃斯地区在中新世早期处于潮湿的暖温带至亚热带气候条件下，这与当前的地中海气候有很大不同。
{"title":"A new species of Pseudotsuga (Pinaceae) from the lower Miocene of Lesvos, Greece, and its palaeogeographical and palaeoclimatic implications","authors":"Yan-Bin Zhu, Ya Li, Jian-Ping Zhang, Yong-Dong Wang, Nikolaos Zouros","doi":"10.1016/j.palwor.2024.06.001","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.06.001","url":null,"abstract":"a Carrière is commonly known as Douglas-fir, a minor genus attributed to Pinaceae. Four extant species are included in this genus, with dispersed distribution in East Asia and western North America. possesses a number of fossil records of needled leaves, seed cones, and seeds. Nevertheless, few reliable fossil wood of this genus has been specifically investigated. Here, we describe some anatomically well-preserved petrified fossil wood from the lower Miocene of Lesvos Island, Greece, as n. sp. The studied fossil wood remains are characterized by the presence of normal axial and radial resin canals, piceoid cross-field pitting, along with distinctive helical thickenings in cell walls consistent with . The present fossil conifer further enriches the species diversity of the Miocene Petrified Forest in Lesvos. The first report of from the southern Europe in this study extends the tempo-spatial distribution patterns of and contributes to further understanding of its origin and evolutionary history. The occurrence of . fossil wood, as well as other palaeontological macrofloral composition evidence, indicates a humid warm temperate to subtropical climatic condition during the early Miocene within the Lesvos, which differs significantly from the current Mediterranean climate.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781787","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.05.011
Javier Luque, Jonatan Bustos, Manuel Páez-Reyes, Alejandro Beltrán-Triviño, Angie Rodríguez, Alexandra Delgado, Johan M. Sánchez, Julián Caraballo, Mikel A. López-Horgue
Despite the rich geological and paleontological record of Colombia, the Putumayo region near Ecuador remains one of the least explored regions in the equatorial Neotropics, mainly due to its thick vegetation, deep rock weathering, soil formation, and ground cover, geographic remoteness, and inaccessibility of well-exposed outcrops. This has resulted in limited comparisons with neighboring basins and thus the generation of more comprehensive biostratigraphic correlations with western and northern South America, as well as other paleobiogeographic regions (e.g., Tethys, Western Interior Seaway). Here, we present 67 occurrences of uppermost Lower Cretaceous to lowermost Upper Cretaceous ammonoids and other macrofossils (e.g., bivalves, decapod crustaceans, osteichthyan fish remains, plant remains), as well as a δC chemostratigraphic curve derived from 105 samples from the middle Albian of the uppermost Caballos Formation and the upper Albian to lower Cenomanian lower Villeta Formation, collected from a stratigraphic section exposed along the Mocoa–San Francisco Road, Putumayo, Colombia, here called the San Francisco section. The chemostratigraphic, carbon-isotope curve for the region shows a great similarity with the shape of the accepted curve for the late Albian Oceanic Anoxic Event 1d, which is characterized by a worldwide long positive δC excursion anomaly. The new biostratigraphic and isotopic data serve as a point of reference to compare the Putumayo Basin with neighboring basins (e.g., Marañon Basin in Perú, Oriente Basin in Ecuador, Upper Magdalena Valley Basin in Colombia), and thus the generation of more comprehensive upper Lower Cretaceous and lower Upper Cretaceous biostratigraphic and chemostratigraphic correlations for northwestern South America.
{"title":"The Early to Late Cretaceous (Albian–Cenomanian) transition in Putumayo, Colombia: a biostratigraphic and carbon isotope stratigraphic correlation for northwestern South America","authors":"Javier Luque, Jonatan Bustos, Manuel Páez-Reyes, Alejandro Beltrán-Triviño, Angie Rodríguez, Alexandra Delgado, Johan M. Sánchez, Julián Caraballo, Mikel A. López-Horgue","doi":"10.1016/j.palwor.2024.05.011","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.011","url":null,"abstract":"Despite the rich geological and paleontological record of Colombia, the Putumayo region near Ecuador remains one of the least explored regions in the equatorial Neotropics, mainly due to its thick vegetation, deep rock weathering, soil formation, and ground cover, geographic remoteness, and inaccessibility of well-exposed outcrops. This has resulted in limited comparisons with neighboring basins and thus the generation of more comprehensive biostratigraphic correlations with western and northern South America, as well as other paleobiogeographic regions (e.g., Tethys, Western Interior Seaway). Here, we present 67 occurrences of uppermost Lower Cretaceous to lowermost Upper Cretaceous ammonoids and other macrofossils (e.g., bivalves, decapod crustaceans, osteichthyan fish remains, plant remains), as well as a δC chemostratigraphic curve derived from 105 samples from the middle Albian of the uppermost Caballos Formation and the upper Albian to lower Cenomanian lower Villeta Formation, collected from a stratigraphic section exposed along the Mocoa–San Francisco Road, Putumayo, Colombia, here called the San Francisco section. The chemostratigraphic, carbon-isotope curve for the region shows a great similarity with the shape of the accepted curve for the late Albian Oceanic Anoxic Event 1d, which is characterized by a worldwide long positive δC excursion anomaly. The new biostratigraphic and isotopic data serve as a point of reference to compare the Putumayo Basin with neighboring basins (e.g., Marañon Basin in Perú, Oriente Basin in Ecuador, Upper Magdalena Valley Basin in Colombia), and thus the generation of more comprehensive upper Lower Cretaceous and lower Upper Cretaceous biostratigraphic and chemostratigraphic correlations for northwestern South America.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782007","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.05.010
Denis Horvath, Xu-Ri Wang, Martin Kundrát
This study presents a new methodology that combines quantitative image analysis, clustering, and statistical techniques to examine the 2D distribution of osteohistological features in an extinct stem-group bird. The driving force of our research was the need to map ontogenetic changes in the spatial density of osteocyte lacunae in the type specimen of from the Lower Cretaceous of China. We particularly focused on developing tools to reveal quantitative aspects of the dynamics in the formation of avascular bone in this active flier. We achieve this goal by proposing an algorithm with the following methodological steps: 1) We obtain relevant coordinate details for pixel locations selected by thresholding the original image with shading as a criterion. 2) We estimate density using the Gaussian kernel estimator and refined it through observations and regression analysis. 3) After slicing the image, we apply k-means clustering to obtain one-dimensional representations of lacunar density. 4) We proceed by implementing weighted averaging employing the k-nearest neighbor approach. Having applied these steps, we are able to quantitatively disclose growth processes previously unnoticed and reveal dynamics in the formation of lacunar bone tissue in the enantiornithine birds capable of power flight.
本研究提出了一种结合定量图像分析、聚类和统计技术的新方法，以研究一种已灭绝的茎类鸟类骨组织特征的二维分布。我们研究的动力是需要绘制中国下白垩统鸟类骨细胞裂隙空间密度的本体变化图。我们特别注重开发工具，以定量揭示这种活跃的飞禽无血管骨骼形成的动态变化。为实现这一目标，我们提出了一种包含以下方法步骤的算法：1) 我们以阴影为标准，对原始图像进行阈值化处理，从而获得像素位置的相关坐标细节。2) 我们使用高斯核估计器估计密度，并通过观察和回归分析对其进行改进。3) 对图像进行切片后，我们采用 K 均值聚类，以获得裂隙密度的一维表示。4) 接下来，我们采用 k 近邻法进行加权平均。应用这些步骤后，我们能够定量地揭示以前未曾注意到的生长过程，并揭示能够进行动力飞行的反鸟类的裂隙骨组织的形成动态。
{"title":"Quantitative insights into osteocyte density developmental patterns in fossilized bone — A new method","authors":"Denis Horvath, Xu-Ri Wang, Martin Kundrát","doi":"10.1016/j.palwor.2024.05.010","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.010","url":null,"abstract":"This study presents a new methodology that combines quantitative image analysis, clustering, and statistical techniques to examine the 2D distribution of osteohistological features in an extinct stem-group bird. The driving force of our research was the need to map ontogenetic changes in the spatial density of osteocyte lacunae in the type specimen of from the Lower Cretaceous of China. We particularly focused on developing tools to reveal quantitative aspects of the dynamics in the formation of avascular bone in this active flier. We achieve this goal by proposing an algorithm with the following methodological steps: 1) We obtain relevant coordinate details for pixel locations selected by thresholding the original image with shading as a criterion. 2) We estimate density using the Gaussian kernel estimator and refined it through observations and regression analysis. 3) After slicing the image, we apply k-means clustering to obtain one-dimensional representations of lacunar density. 4) We proceed by implementing weighted averaging employing the k-nearest neighbor approach. Having applied these steps, we are able to quantitatively disclose growth processes previously unnoticed and reveal dynamics in the formation of lacunar bone tissue in the enantiornithine birds capable of power flight.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782010","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}
The Xinji Formation (Cambrian Series 2) in the southern margin of the North China Plate developed typical siliciclastic storm deposits and abundant trace fossils. These deposits are characterized by essential indicators, such as erosional surfaces, lag deposits, blocky beddings, hummocky cross stratifications, horizontal or wavy beddings. Storm deposits in the study area are dominated by the development of hummocky cross stratifications, which is categorized into five storm deposit types based on the arrangement of different sedimentary units in the profile. These five types of storm deposits from I to V show the transition from proximal storm deposits to distal storm deposits, the gradual weakening of storm intensity, and the associated growth of quiescent intervals. The trace fossils are mainly developed in the sandstone-mudstone interbeds between storm events and include 14 ichnospecies in 11 ichnogenera: isp., , , , , , isp., , , , isp., isp., , . By analyzing the ichnological index (burrow size, BPBI, ichnodiversity and ichnodisparity) from different storm deposits, it can be seen that from storm deposit type I to storm deposit type V, the ichnological index shows an increasing trend. Combined with the relationship between storm deposits and trace fossils, it is inferred that differences in storm intensity result in different colonization windows, and thus variations in ichnological index of preserved trace fossils. Based on the characteristics of storm deposits and distribution of trace fossils, the preservation forms of trace fossils under storm influence are explored.
华北板块南缘的辛集地层（寒武系 2）发育典型的硅质风暴沉积和丰富的微量化石。这些沉积的基本特征包括侵蚀面、滞后沉积、块状层理、驼峰状交叉层理、水平或波浪状层理等。研究区域的风暴沉积以驼峰状交叉层理的发育为主，根据不同沉积单元在剖面上的排列，可分为五种风暴沉积类型。从 I 到 V 这五种类型的风暴沉积显示了近端风暴沉积向远端风暴沉积的过渡、风暴强度的逐渐减弱以及与之相关的静止期的增长。痕量化石主要发育在风暴事件之间的砂岩-泥岩夹层中，包括 11 个化石属中的 14 个化石种：isp.、、、、、isp.、、、isp.、isp.、、、isp.、isp.、isp.、isp.。通过分析不同风暴沉积物的虫态指数（洞穴大小、虫态指数、虫态多样性和虫态差），可以看出从风暴沉积物 I 型到风暴沉积物 V 型，虫态指数呈上升趋势。结合风暴沉积与痕量化石之间的关系，可以推断风暴强度的不同会导致不同的定殖窗口，从而使保存下来的痕量化石的生态指数发生变化。根据风暴沉积和痕量化石的分布特征，探讨了风暴影响下痕量化石的保存形式。
{"title":"Storm deposits and trace fossils of Xinji Formation (Cambrian Series 2) in the southern margin of North China Plate","authors":"Ming-Yue Dai, Lan-Lan Han, Yong-An Qi, Yao-Gang Du, Zhong-Lei Yin, Song-Hua Chen, Shi-Yun Qing","doi":"10.1016/j.palwor.2024.05.009","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.009","url":null,"abstract":"The Xinji Formation (Cambrian Series 2) in the southern margin of the North China Plate developed typical siliciclastic storm deposits and abundant trace fossils. These deposits are characterized by essential indicators, such as erosional surfaces, lag deposits, blocky beddings, hummocky cross stratifications, horizontal or wavy beddings. Storm deposits in the study area are dominated by the development of hummocky cross stratifications, which is categorized into five storm deposit types based on the arrangement of different sedimentary units in the profile. These five types of storm deposits from I to V show the transition from proximal storm deposits to distal storm deposits, the gradual weakening of storm intensity, and the associated growth of quiescent intervals. The trace fossils are mainly developed in the sandstone-mudstone interbeds between storm events and include 14 ichnospecies in 11 ichnogenera: isp., , , , , , isp., , , , isp., isp., , . By analyzing the ichnological index (burrow size, BPBI, ichnodiversity and ichnodisparity) from different storm deposits, it can be seen that from storm deposit type I to storm deposit type V, the ichnological index shows an increasing trend. Combined with the relationship between storm deposits and trace fossils, it is inferred that differences in storm intensity result in different colonization windows, and thus variations in ichnological index of preserved trace fossils. Based on the characteristics of storm deposits and distribution of trace fossils, the preservation forms of trace fossils under storm influence are explored.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782014","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 : 2024-07-17DOI: 10.1016/j.palwor.2024.05.004
Jian-Guo Hui, Su-Xin Yin, Xiao-Liang Cai, Chong Dong, Yuan-Dong Liu, Ning Tian, Gong-Le Shi
Early Cretaceous was a key period for the evolution of terrestrial ecosystems. In southeastern China, the late Early Cretaceous (Aptian–Albian) floras are relatively well known and characterized by diverse Cheirolepidiaceae, but the early Early Cretaceous floras in southeastern China are poorly known mainly because of the lack of plant fossils. Here we report petrified woods from a new early Early Cretaceous locality in Qingyuan, southern Zhejiang Province, southeastern China. The new fossil woods collected from the Xishantou Formation (earliest Berriasian, earliest Early Cretaceous) are assigned to Tian, Zhu, and Wang based on the anatomy of the secondary xylem. The new material of from Qingyuan lacks distinct growth rings or resin canals and has mixed type pitting on the radial walls of the tracheids, araucarioid cross-field pitting, and uniseriate rays. It is the earliest record of in southeastern China. has been regarded as the wood of the extinct conifer family Cheirolepidiceae and grew in arid to semi-arid environments. Evidence also suggests Cheirolepidiaceae played an important role in the vegetation of southeastern China throughout the Early Cretaceous.
{"title":"New record of Brachyoxylon wood from the Lower Cretaceous of Qingyuan, southeastern China and its palaeoclimatic implications","authors":"Jian-Guo Hui, Su-Xin Yin, Xiao-Liang Cai, Chong Dong, Yuan-Dong Liu, Ning Tian, Gong-Le Shi","doi":"10.1016/j.palwor.2024.05.004","DOIUrl":"https://doi.org/10.1016/j.palwor.2024.05.004","url":null,"abstract":"Early Cretaceous was a key period for the evolution of terrestrial ecosystems. In southeastern China, the late Early Cretaceous (Aptian–Albian) floras are relatively well known and characterized by diverse Cheirolepidiaceae, but the early Early Cretaceous floras in southeastern China are poorly known mainly because of the lack of plant fossils. Here we report petrified woods from a new early Early Cretaceous locality in Qingyuan, southern Zhejiang Province, southeastern China. The new fossil woods collected from the Xishantou Formation (earliest Berriasian, earliest Early Cretaceous) are assigned to Tian, Zhu, and Wang based on the anatomy of the secondary xylem. The new material of from Qingyuan lacks distinct growth rings or resin canals and has mixed type pitting on the radial walls of the tracheids, araucarioid cross-field pitting, and uniseriate rays. It is the earliest record of in southeastern China. has been regarded as the wood of the extinct conifer family Cheirolepidiceae and grew in arid to semi-arid environments. Evidence also suggests Cheirolepidiaceae played an important role in the vegetation of southeastern China throughout the Early Cretaceous.","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141781739","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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