The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports ...The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports the interpretation of corystosperms as an evolutionary intermediate between gymnosperms and angiosperms.The first application of X-Ray fluorescence(XRF)chemical analysis to fossil wood taxa of Fengweioxylon yielded the above conclusion.By using growth ring analysis and ecological reconstructions,we suggest that corystosperms were large evergreen trees with leaf retention periods of three to five years.They likely thrived in warm summer environments where prolonged foliage retention provided adaptive benefits.展开更多
Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we...Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we investigated the external morphology and internal structure using Light Microscopy(LM),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).According to TEM observations,the exine of Quantonenpollenites pollen is unstratified with the absence of a columellar layer,and the exine is tightly connected with the intine.Based on comprehensive morphological evidence,especially the lack of columellar layer which is typical characteristics existing in almost all angiosperm pollen,the botanical affinity of Quantonenpollenites should be attributed to gymnosperms rather than angiosperms as previously thought.Through comparative analysis,it may have a close affinity with Ephedra,but further analytical data are still needed for verification.As a characteristic palynological type of the Quantou Formation in the Songliao Basin,the occurrence of Quantonenpollenites has indicative significance for determining the age of the hosting strata.By systematically clarifying the phylogenetic affiliation of Quantonenpollenites,together with the other associated palynomorphs,this study provides crucial reference materials for defining the stratigraphic age range of the Quantou Formation(Cenomanian to early Turonian),improves the resolution of stratigraphic age calibration of the Quantou Formation,and provides key paleontological evidence for the refined division of the terrestrial Cretaceous chronostratigraphic framework in the Songliao Basin.展开更多
Drepanophycus(镰蕨属)是早期石松类的代表类群之一,其在全球广泛分布,时间延限为早泥盆世至晚泥盆世。本研究首次描述了产自云南曲靖太和剖面中泥盆统海口组中的Drepanophycus qujingensis Li et Edwards,其营养轴平躺或穿层保存,长度...Drepanophycus(镰蕨属)是早期石松类的代表类群之一,其在全球广泛分布,时间延限为早泥盆世至晚泥盆世。本研究首次描述了产自云南曲靖太和剖面中泥盆统海口组中的Drepanophycus qujingensis Li et Edwards,其营养轴平躺或穿层保存,长度可达172.0 mm,三角形、镰刀形的小型叶稀疏排列在营养轴上,长约4.6 mm,气孔类型为无规律型。另外,回顾了Drepanophycus在中国的百年研究历史,分析和总结了该属的分类学特征。新材料的发现及对前人标本的重新研究确凿地证明了Drepanophycus在华南地区可延伸至中泥盆世,且华南地区中泥盆世植物群既有Drepanophycus和真叶植物基部类群等“始植物群”分子,又有异孢石松类和似真蕨类等“古生代植物群”分子。在同一剖面海口组中还观察到大量古土壤发育,其中的根状茎极可能属于Drepanophycus,表明草本石松类在中泥盆世发挥了固定土壤、减缓侵蚀、塑造地球景观的功能。展开更多
文摘云南曲靖中泥盆统海口组植物化石是南方植物区系的典型代表,植物组合以石松类为主,兼具大量的地方性特色植物,被称为海口植物群或西冲植物群。本研究基于云南曲靖中泥盆统海口组的植物化石新材料,识别出2种石松类:Lepidodendropsis zhanyiense Zheng,Wang,Li,Liu et Xue sp.nov.(沾益拟鳞木,新种)和Minarodendron cathaysiense(Schweitzer et Cai)Li(华夏小木)。沾益拟鳞木具假轮状排列的简单叶基,细枝的叶基上部有向两侧延伸的浅沟状假叶痕,在粗枝上假叶痕呈规则的M型结构;营养叶不分叉,纤细,呈线形;孢子叶呈勺状,在茎干密集排列形成长达18 cm的繁殖区,孢子囊椭圆形,着生于孢子叶的近轴面。华夏小木的标本显示了与前人描述相似的茎轴形态及叶基排列方式。在新材料的基础上,通过计算机三维建模的方法,探讨了泥盆纪石松类植物的叶基形态变化,指出沾益拟鳞木及其他相似植物叶基上的M型结构并非叶舌穴。中泥盆世石松类植物显示出相似的、原始的叶基形态,且一些类型演化为较大的体型(即树型习性),体现了它们在营养结构方面相似的进化程度。华南中泥盆世石松类植物群主要分布于河流或滨岸,具有显著的区域性特征,可能反映出华南地区较为隔离的古地理位置。研究成果进一步丰富了华南中泥盆世的植物多样性,也为石松类植物的演化提供了新的证据。
基金supported by the National Natural Science Foundation of China(U2544204,42172034,42330208,42288201)the China Geological Survey Project(Grant Nos.DD20243469,DD20221829).
文摘The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports the interpretation of corystosperms as an evolutionary intermediate between gymnosperms and angiosperms.The first application of X-Ray fluorescence(XRF)chemical analysis to fossil wood taxa of Fengweioxylon yielded the above conclusion.By using growth ring analysis and ecological reconstructions,we suggest that corystosperms were large evergreen trees with leaf retention periods of three to five years.They likely thrived in warm summer environments where prolonged foliage retention provided adaptive benefits.
基金supported by the National Key Research and Development Program of China (2023YFC2906701)National Natural Science Foundation of China (42372041, 42072027)China Geological Survey (DD20221646)
文摘Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we investigated the external morphology and internal structure using Light Microscopy(LM),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).According to TEM observations,the exine of Quantonenpollenites pollen is unstratified with the absence of a columellar layer,and the exine is tightly connected with the intine.Based on comprehensive morphological evidence,especially the lack of columellar layer which is typical characteristics existing in almost all angiosperm pollen,the botanical affinity of Quantonenpollenites should be attributed to gymnosperms rather than angiosperms as previously thought.Through comparative analysis,it may have a close affinity with Ephedra,but further analytical data are still needed for verification.As a characteristic palynological type of the Quantou Formation in the Songliao Basin,the occurrence of Quantonenpollenites has indicative significance for determining the age of the hosting strata.By systematically clarifying the phylogenetic affiliation of Quantonenpollenites,together with the other associated palynomorphs,this study provides crucial reference materials for defining the stratigraphic age range of the Quantou Formation(Cenomanian to early Turonian),improves the resolution of stratigraphic age calibration of the Quantou Formation,and provides key paleontological evidence for the refined division of the terrestrial Cretaceous chronostratigraphic framework in the Songliao Basin.
文摘Drepanophycus(镰蕨属)是早期石松类的代表类群之一,其在全球广泛分布,时间延限为早泥盆世至晚泥盆世。本研究首次描述了产自云南曲靖太和剖面中泥盆统海口组中的Drepanophycus qujingensis Li et Edwards,其营养轴平躺或穿层保存,长度可达172.0 mm,三角形、镰刀形的小型叶稀疏排列在营养轴上,长约4.6 mm,气孔类型为无规律型。另外,回顾了Drepanophycus在中国的百年研究历史,分析和总结了该属的分类学特征。新材料的发现及对前人标本的重新研究确凿地证明了Drepanophycus在华南地区可延伸至中泥盆世,且华南地区中泥盆世植物群既有Drepanophycus和真叶植物基部类群等“始植物群”分子,又有异孢石松类和似真蕨类等“古生代植物群”分子。在同一剖面海口组中还观察到大量古土壤发育,其中的根状茎极可能属于Drepanophycus,表明草本石松类在中泥盆世发挥了固定土壤、减缓侵蚀、塑造地球景观的功能。
