Middle Permian smaller foraminifers from the Maokou Formation at the Tieqiao section,Guangxi, South China

This paper documents smaller foraminifers from the Maokou Formation (Guadalupian) at the Tieqiao section in Laibin area, South China. The assemblage of smaller foraminifers reported herein consists of 69 species of 42 genera. Although the Maokou Formation of this section was deposited in a relatively deep-water environment, smaller foraminifers are diverse and abundant, especially in debris flow deposits and thin turbidite beds. This fauna bears most similarity with coeval foraminiferal assemblages from the other Palaeotethyan regions. There is a sharp decrease in the diversity and abundance of smaller foraminifers at the lithological boundary between the Maokou and Heshan formations. An overwhelming majority of genera of smaller foraminifers that occur in the Maokou Formation at this section can be found in the Lopingian strata of South China. The study of smaller foraminiferal fauna of the Guadalupian at the Tieqiao section indicates a much less pronounced effect of the pre-Lopingian crisis on smaller foraminifers.     

双性封印木孢子叶球在内蒙古乌达煤田下二叠统太原组凝灰岩层中的发现

封印木在石炭纪–二叠纪欧美植物群的沼泽森林中占据重要地位,化石记录十分丰富,在华夏植物群中的记录则较为稀少。已知这类植物的孢子叶球都是单性的。本文基于内蒙古乌达煤田下二叠统太原组凝灰岩中的化石材料,报道了一种石松类双性孢子叶球类型,与封印木茎干及叶保存于原位埋藏的火山凝灰岩植物群中,共同构成封印木树冠。该类孢子叶球呈圆柱形,基部具柄;孢子叶紧密螺旋排列,近轴部分为水平伸出的孢子叶柄,远轴部分为上翘的远端叶片,两者转折处具明显的踵;孢子囊单生于孢子叶柄近轴面,大孢子囊位于孢子叶球的中部-基部,小孢子囊位于中部-顶部。该类双性封印木孢子叶球的发现增加了封印木繁殖器官的多样性和复杂性,为进一步探讨这类植物的系统分类与演化提供了重要信息。     

黔南独山地区泥盆系法门阶–石炭系杜内阶革老河组 和汤粑沟组长身贝类新认知

本文描述了在黔南独山县其林寨剖面和黎家寨剖面上泥盆统革老河组和下石炭统汤粑沟组中发现的长身贝类化石共8属10种(含未定种)。其中, 在革老河组中发现有3属4种: Productella? sp.、Yanguania dushanensis、Xinshaoproductus xinshaoensis和X. quadrata; 汤粑沟组中有8属9种: Productella? sp.、Hunanoproductus hunanensis、Spinocarinifera qilinzhaiensis sp. nov.、Yanguania dushanensis、Y.? sp.、Xinshaoproductus xinshaoensis、Tomiproductus sp.、Ozora? sp.和Ericiatia kiangsuensis。总体而言, 革老河组和汤粑沟组中的长身贝类在组成上主要以Productoidea超科中Productidae科的分子为主, Productellidae科和Echinoconchoidea超科中Sentosiidae科的分子各有1种。本文记述的Hunanoproductus和Xinshaoproductus系在黔南地区首次发现, 并且Xinshaoproductus在黔南地区的首现层位低于湘中地区。常见于欧亚地区的中泥盆统吉维特阶至上泥盆统弗拉斯阶及湘中地区上泥盆统的Productella属, 在黔南地区上延到了下石炭统的汤耙沟组中, 为该属最晚的化石记录。Spinocarinifera和Tomiproductus是欧亚、北美、西澳和北非等地杜内阶或杜内阶-维宪阶中的常见分子, 汤粑沟组中发现的S. qilinzhaiensis sp. nov.则是目前已知该属在华南地区的代表。该种以近方圆形的轮廓、铰合线短、耳翼小、放射状壳线连续但微弱为特征, 区别于该属的其他种。而Tomiproductus在华南地区见于湘中刘家塘组的上部和下扬子地区的金陵组。Ozora属于美国密苏里地区维宪阶下部的代表分子, 亦见于墨西哥南部的下石炭统。如果鉴定无误, 黔南地区的发现则有可能代表了该属最早的化石记录。革老河组的长身贝类组成属种单调, 以Yanguania、Xinshaoproductus属等地方性分子为特征; 随着杜内期的海侵, 汤耙沟组中的长身贝类组成与湘中地区的更为相近, 生物多样性显著增加, 既继承了革老河组中的地方性分子, 同时在属级分类单元中也出现了一些在欧美、澳大利亚等地区的类型, 如Spinocarinifera、Tomiproductus和Ozora属。反映了从杜内期开始的海侵, 使华南地区的腕足动物群与欧美地区同时期的腕足动物群之间开始发生较为密切的生物地理区系联系。     

柴达木盆地宗马海湖地区始新统下干柴沟组 轮藻植物群

柴达木盆地北缘宗马海湖地区始新统下干柴沟组在一道沟剖面出露良好, 本文详细描述了该剖面下干柴沟组的岩性特征, 该组以棕红色泥岩为主, 局部夹浅灰绿色含石膏中细砂岩、含钙质粉砂质细砂岩及少量含砾中粗砂岩、褐红色灰岩。在该剖面发现轮藻化石2属2种: Lamprothamnium ganchaigouensis (Tang and Di) Li et al. comb. nov.和Lychnothamnus vectensis (Groves) Soulié-M?rsche, 前者为新联合属种。L. vectensis主要发现于欧洲始新统?渐新统, 在我国始新统系首次报道。本文以居群为单位, 讨论了L. vectensis的种内形态变化, 包括藏卵器尺寸和顶部装饰的连续变化。欧洲L. vectensis居群的藏卵器尺寸随着纬度的升高有变大的趋势, 而柴达木盆地的纬度低于欧洲埃布罗盆地和巴黎盆地的纬度, 它所产的L. vectensis居群藏卵器尺寸却更大, 推测与柴达木盆地古湖泊水体清澈度和/或温度更高相关。     

全尾宽背虫Bathynotus holopygus (Hall, 1859)在 贵州剑河八郎寒武系凯里组的首次发现及意义

宽背虫属Bathynotus (Hall, 1859)广泛分布于劳伦古大陆、中国华南地区、澳大利亚和西伯利亚, 为寒武纪第二世末期最重要的标志性三叶虫之一,已成为寒武系划分的重要指示化石。其模式种B. holopygus以其狭长的颊刺、胸轴宽, 第11节肋刺巨大, 第12、13节肋刺不发育为主要特征;具有很强的地域性, 仅分布于华南和北美, 在华南主要见于寒武系扬子区与江南区之间过渡区的黔东地区。B. holopygus产出地层延限较窄, 仅见于寒武系第二统第四阶顶部。本文所描述的部分标本采自贵州剑河八郎苗板坡剖面苗岭统及乌溜阶界线之下2 m左右, 是在该地的首次报道, 也是全球仅有的第4个产地。笔者通过数理统计值分析进一步描述B. holopygus的特征和发育趋势, 为进一步属种研究提供新材料; 根据新发现的唇瓣标本进一步推测其唇瓣与腹边缘为愈合状态。     

A new crocodylomorph tooth assemblage from the Tataouine Basin and comments on the stratigraphic context of the Douiret Formation

A new crocodylomorph tooth assemblage from the Lower Member of the Douiret Formation (uppermost Jurassic–lowermost Cretaceous) in southeastern Tunisia is described. These teeth have been grouped into five morphotypes based on their diagnostic morphological features. The sample includes teeth, which have not been reported until now, such as non-Machimosaurini teleosauroid teeth, and labiolingually compressed tooth crowns with cutting edges devoid of serrations. Certain minor morphometric differences have been interpreted as ontogenetic or being possibly related to the position of the teeth in the jaws. Three trophic entities have subsequently been defined on the basis of the morphological characteristics of the teeth, and a possible niche partitioning between at least three crocodylomorph taxa is highlighted for the first time in the Tataouine Basin. On the other hand, the stratigraphic context of the Douiret Formation is thoroughly discussed in order to show how stratigraphic uncertainties could significantly impact previous attempts at reconstructing the macroevolutionary history of Crocodylomorpha. The latter should be treated with caution when the stratigraphic context of the fossil bearing formation remains a subject of debate.     

Stratigraphic distribution of shallow-water benthic foraminifera from the Lower Cretaceous Taft formation,Central Iran (Yazd Block), with evidence for the importance of hiatuses

In this contribution, two stratigraphic sections are described through the Lower Cretaceous shallow-water platform sediments (Taft formation) from the northern Tethys, which are located in the Yazd Block, Central Iran. Benthic foraminifera are used to propose a biostratigraphy for these successions. They are grouped around several assemblage zones, and several genera and species are reported from the Yazd Block basin for the first time (e.g., Arenobulimina cochleata, A. meltae, Belorusiella sp., Bolivinopsis cf. labeosa, Decussoloculina barbui, Martinotiella jucunda, Myncina bulgarica, Novalesia cornucopia, Sabaudia briacensis, Simplorbitolina manasi). Their presence can provide a better understanding for the paleogeographic reconstruction of the Tethyan seaways. Furthermore, they represent candidates as potential index fossils in the Lower Cretaceous stratigraphy of the Yazd Block. The new biostratigraphic data allow to date the Lower Cretaceous successions between the probable Valanginian and the late Aptian. Based on the absence of early Barremian indicators and also late Aptian markers, two hiatuses are recognized through the Taft formation. This formation also displays a diachrony in ages at its base and top, which suggests the effect of long-term subsidence in the Yazd Block during the Early Cretaceous, following the Cimmerian phase of orogeny.     

中国早白垩世脉翅目草蛉科原草蛉属新种记述

本文记述了采集自我国辽宁省北票市中生界下白垩统义县组地层的草蛉科篱草蛉亚科原草蛉属一新种,短脉原草蛉。该属此前仅在丹麦和加拿大的新生界地层中发现2种,新种与该属的其它种具有显著差异,如前翅基部第一支r1-rs横脉位于Rs起始处与Rs第一支脉分出处之间,R1在翅端前结束。本文简要对比了原草蛉属与篱草蛉亚科其它属的特征差异,并对新种的归属及其与该属其它种的特征差异进行了讨论。     

Cyclocrinitids from the Lower Palaeozoic Tethyan sequence of Spiti,India

Well preserved cyclocrinitids (calcareous green algae) are reported from early Palaeozoic deposits of Spiti, Himachal Pradesh, India. Casts of the algal fossils are preserved in calcareous grey siltstone unit of the Takche Formation (Late Ordovician–Early Silurian) which appears rusty/earthy brown due to weathering. The assemblage includes Cyclocrinites favus, Cyclocrinites pyriformis, Cyclocrinites cf. welleri, Cyclocrinites sp. and Cyclocrinites globosus. Both Cyclocrinites cf. welleri and Cyclocrinites globosus are reported for the first time from the entire Tethyan Himalaya, India. The described algal flora basically denotes relatively shallow marine depositional setting and low to moderate hydrodynamic conditions.