Volume 60,Issue 2,2021 Table of Contents

1 Cover illustration: Cretpenthetria burmensis gen. et sp. nov., Hukawng Valley, Myanmar, mid-Cretaceous.

Courtesy of Wang Bo , Li Lin-wei , the photographer (refer to Li , in this issue).

2021, 60(2). CSTR:

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2 Deduction of conodont’s feeding habit: evidence from late Cambrian to early Ordovician conodont fossils, North, China

CHEN Xin-ran , YANG Ai-hua , DU Sheng-xian , CHEN Jun , HU Chun-lin

2021, 60(2):201-214. DOI: 10.19800/j.cnki.aps.2020052 CSTR:

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As a pharyngeal feeding organ of conodont animals, the conodonts have their unique biological characteristics. Based on the abundant conodont fossils data from late Cambrian?earliest Ordovician in the Yaowang Mountain section in Qingzhou, Shandong Province, North China, this article discusses the physiological wear of the conodonts when exercising their feeding functions such as filter-feeding. Three types of wear of the Carboniferous conodonts: breakage (part of conodont is broken by external force and removed from the main body), spalling (exfoliation of outer growth layer and exposure of inner growth layer), and polishing (surface ornamentation of conodont becoming shallow or disappearing because of abrasion) can be compared with the conodonts in this study. A new wear method: grinding (similar to the polishing process, but after surface ornamentation disappeared, abrasion keeps happening and makes the surface rough) and a phenomenon of repair after wear are proposed. The mineral composition of conodonts is mainly fluorapatite, and its Mohs’ scale of hardness is 5. Those minerals that can cause spalling and grinding of co-nodonts should be harder than fluorapatite. The common minerals with hardness higher than 5 in Mohs’ scale of hardness are feldspar and quartz, which are the main sand components. Conodont animals may swallow sand from the seafloor, find out the food, transport it into the digestive tract with the conodont apparatus, and then spit out the large or small sand. This method of feeding can be called the “sand grain rummaging type”. Conodont animals with this feeding mode need to live close to the sand of the seafloor. Apart from breakage, spalling, and grinding, there is another mode of wear: polishing. The particles that can cause polishing should be smaller and softer than fluorapatite crystals. The common mineral in the sea with a hardness lower than 5 is calcite (Mohs’ scale of hardness is 3). Therefore, it can be inferred that the food of conodont animals also includes zooplankton with calcite or aragonite shells. When taking small zooplankton into the mouth, a large amount of calcite shells wears out the tip of the conodont and polish its surface. Conodont animals with this mode of feeding are called the “plankton filter-preying type”.

3 First record of Cheirocrinus penniger (Eichwald, 1842) (Cystoidea) from the Ordovician Miaopo Formation in western Hubei, China

MAO Ying-yan , FANG Xiang , YU Shen-yang , SONG Yan-yan , LI Yue

2021, 60(2):215-223. DOI: 10.19800/j.cnki.aps.2019035 CSTR:

[Abstract](330) [HTML](0) [PDF 6.72 M](1963)

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The Miaopo Formation of the Middle–Upper Ordovician transition in western Hubei Province of China, is a few meters thick and composed of shales intercalated with thin-bedded bioclastic limestones. It was deposited in an intra–platform depression with marine–floor depth below major wave-base of the Yangtze Epicontinental Sea. The unit is high bio-diversity and has an abundance of macrofossils. We report for the first time on Cystoidea fossils from the shales in the mid-upper part of the Miaopo Formation at Chenjiahe section of northern Yichang, and Zhenjin section of Yuan’an County. Based on the co-occurred graptolitic faunas, the units yielding more than 30 Cystoidea fossils are assigned to the Nemagraptus gracilis Biozone of the basal Sandbian, Upper Ordovician. Cystoidea fossils are morphologically identified and described as Cheirocrinus penniger (Eichwald, 1842). In taphonomic aspect, the C. penniger fossils from the Zhenjin section are dominated by aggregated and compressed calyx plates, including a complete specimen with column preserved. Same species from the equivalent horizon at the Chenjiahe section are single disarticulated calyx plates. The Cheirocrinus was a cosmopolitan genus in the Ordovician. Cheirocrinus of the present discovery expands the temporal and spatial distribution of the genus, i.e. from the Early Ordovician Tonggao Formation (slope facies) to the Late Ordovician Miaopo Formation (intra-platform depression) in the South China Block.

4 Eoangiopteris congestus sp. nov., a marattialean fern from the Lower Permian Taiyuan Formation of Wuda Coalfield, Inner Mongolia

SUN Wen-jun , LI Dan-dan , ZHOU Wei-ming , BEK Ji?í , LIU Lu-jun , WANG Jun

2021, 60(2):224-242. DOI: 10.19800/j.cnki.aps.2020012 CSTR:

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A new marattialean fern Eoangiopteris congestus sp. nov. is described from the volcanic tuff bed in the uppermost part of the Taiyuan Formation, within Wuda Coalfield, Inner Mongolia. It consists of organically connected Psaronius –type stem, Pecopteris –type vegetative fronds and Eoangiopteris –type fertile fronds. Vegetative fronds are tripinnate. Penultimate and ultimate pinnae are both linear. Pinnules are typically pecopterid, oblong in outline, with decurrent midvein and once–bifurcated lateral veins. Vegetative pinnules are attributable to Pecopteris orientalis (Schenk) Potonié type. Fertile pinnules are identical to these vegetative pinnules. Bilaterally symmetrical synangia are borne in a single row on each side of the midvein, closely arranged along the lateral veins, and composed of 6–8 sporangia that are attached to a parenchymatous receptacle. Sporangia are elongate and exannulate, fusiform in shape. The outer facing walls of the sporangia are two to three cells thick, while the inner facing walls are reduced to one cell thick. In situspores are trilete, oval to circular in shape with prominently microspinate sculpture. They are comparable to the dispersed miospore genus Apiculatisporites. The new discovery represents the stratigraphically earliest occurrence of Eoangiopteris in Cathaysia. In addition, these bilaterally symmetrical synangia are distinctly different from those radially symmetrical synangia (Asterotheca) which previously were considered to be the fertile organs of Pecopteris orientalis–type pinnules, suggesting one morphotype of fossil pinnule may correspondence to several types of fructifications in palaeobotanical researches.

5 A new genus and species of Bibionidae (Diptera: Bibionoidea) from mid-Cretaceous Kachin amber

LI Ling-wei , ZHANG Qing-qing , XIAO Chuan-tao

2021, 60(2):243-252. DOI: 10.19800/j.cnki.aps.2021018 CSTR:

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A new genus and species, Cretpenthetria burmensis gen. et sp. nov., is established and attributed to the family Bibionidae on the basis of a new well-preserved specimen from mid-Cretaceous amber of Kachin State, northern Myanmar. The new genus differs from other genera within Bibionidae in the following characteristics: 1) antennae elongated, about twice longer than head length; 2) vein Sc ending about at wing mid-length and opposite of basal 1/3 length of vein R_2+3+4+5; 3) R₂₊₃ equals in length to R_2+3+4+5 and Rs. This finding improves not only the palaeodiversity of Bibionidae in Cretaceous amber, but also provides important three-dimensional morphological evidence for the early evolution of Bibionidae.

6 Palaeo-CO2 estimation of the Early Jurassic based on Cheirolepidiaceous conifer in the Junggar Basin, Xinjiang, China

LI Ting , YANG Xiao-Ju , DENG Sheng-hui

2021, 60(2):253-262. DOI: 10.19800/j.cnki.aps.2020019 CSTR:

[Abstract](457) [HTML](0) [PDF 11.81 M](2336)

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The atmospheric carbon dioxide concentration of the Early Jurassic has been estimated based on the stomata ratio method by using Brachyphyllum (Hirmeriella?) sp., an extinct fossil conifer of Cheirolepidiaceae. The fossil materials were collected from the Early Jurassic Sangonghe Formation in the Junggar Basin, northern Xinjiang, China. The stomatal parameters (stomatal density and stomatal index) of cuticle were analyzed, and the stomatal index was used to estimate the Palaeo-pCO₂. The average stomatal density was 96.4±19.4/mm² and the average stomatal index value was 3.7 ± 0.3. To calculate the stomatal ratio and estimate the atmospheric carbon dioxide concentration, the Athrotaxis cupressoides (SI = 9.4 ± 3.05) was selected as a nearest living equivalent species for Brachyphyllum. The estimated atmospheric CO2 content were 940.6 ± 77.3 ppm and 1567.6 ± 128.8 ppm on the basis of Modern standardization and Carboniferous standardization respectively. The average estimate of the two standardizations indicates a Palaeo-pCO₂ of 1254.1 ± 103.0 ppm in the Early Jurassic (Early Toarcian). The value of atmospheric pCO2 of the Early Jurassic, as previous studies, was 900?1500 ppm by stomata ratio method based on the fossil Ginkgo species. The present estimation from a conifer of Brachyphyllum is broadly consistent with the previous estimates which may indicate that the reliability of Cheirolepidiaceous conifer in Palaeo-pCO₂ estimates during the Jurassic period. The strongly xeromorphic characters of the present fossil plant and the relatively high atmospheric pCO₂ indicate that a warm and dry climate dominated the Junggar Basin during the Early Jurassic (Early Toarcian), and that may be linked to the Toarcian Oceanic Anoxic Event (T-OAE).

7 Palynological assemblages from the Tuchengzi and Dabeigou formations in the Luanping Basin at Sanchazi Section, Northern Hebei Province and their implications

LIN Miao-qin , LI Jian-guo

2021, 60(2):263-280. DOI: 10.19800/j.cnki.aps.2020072 CSTR:

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The Tuchengzi and Dabeigou formations of the Hebei and Liaoning Provinces are of great significance for the Jurassic–Cretaceous stratigraphic division and correlation in northern China. However, the geological age of the two formations is still controversial, and only preliminary researches have been done on the palynostratigraphy. In this paper, moderately diverse pollen and spores are recovered from the Tuchengzi and Dabeigou formations at Sanchazi, Jingshang Village, Luanping County, northern Hebei Province, which comprise 50 genera and 28 species together with some indeterminate species as well. The palynoassemblage of the Tuchengzi Formation, namely Classopollis–Cooksonites–Ephedripites assemblage, is characterized by the predominance of Classopollis and considered to be Berriasian in age (Early Cretaceous) by the occurrence of Cooksonites variabilis、Crybelosporites punctatus and Ephedripites (E.). The Bisaccates–Foraminisporis assemblage recovered from the Dabeigou Formation is dominated by gymnospermous pollen and is evidenced of a middle–late Valanginian age by the occurrence of such age-diagnostic elements as Crybelosporites punctatus, Ephedripites (E.) crassistriatus, Foraminisporis wonthaggiensis, Jiaohepollis and Rugubivesiculites spherisaccatus. The present work uncovers an Early Cretaceous palynoflora from the top of the First Member of the Tuchengzi Formation for the first time, implying that the Jurassic–Cretaceous boundary in northern China lies within the First Member of the Tuchengzi Formation. Our research also shows the Bisaccates–Foraminisporis assemblage of the Dabeigou Formation in the Luanping Basin, northern Hebei Province is correlative to that from the top of the Third Member of the Tuchengzi Formation and the lower part of the Yixian Formation in the Jinlingsi–Yangshan Basin, western Liaoning Province, which means an equivalency of these strata.

8 Alteration microstructures in seafloor basaltic glass: New material for exploring the subseafloor deep biosphere

LU Xuan-chen , XIE Wei , LUO Mao , HAN Xi-qiu , YU Xing , LIU Ji-qiang , QIU Zhong-yan

2021, 60(2):281-298. DOI: 10.19800/j.cnki.aps.2020071 CSTR:

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Bioalteration microstructures in basaltic glasses are those pits and grooves formed by microbial metabolisms. Microbes produce organic acid while absorbing nutrients within basaltic glasses, dissolving the basaltic glasses and forming bi-oalteration microstructures. Bioalteration microstructures within basalts not only occur in modern oceanic crusts, but have been discovered in ophiolites and greenstone belts representing ancient oceanic crusts. Studying the morpho-logical characteristics, formation mechanisms and spatio-temporal distributions of bioalterated microstructures within basaltic glasses is thus pivotal to exploring the origin and evolution of early lives on Earth, and provide new materials to understand the composition of microbial organisms in the sub-seafloor deep biosphere and their spatio-temporal dis-tribution characteristics. Morphologically, bioalterated microstructures within basaltic glasses can be divided into granular and tubular microstructures. However, abiotic microstructures can also occur in basalt glasses mimicking those bio-alterted microstructures. Thus, multi-disciplinary studies combining morphologies, elemental and isotopic geo-chemistry, organic and DNA detection are all significant in distinguishing bioalterated microstructures from abiotic ones. A summary of occurrences of bioalteration microstructures from geological records show that they occur more common than previously thought, and the vertical distribution of these microstructures within oceanic crusts may be closely related to the porosity and permeability of basaltic rocks. In addition, different seafloor environmental condi-tions, such as redox, pH, water depth, temperature, and porosity, can all greatly affect the composition of microbial community and their subsequently formed bioalteration microstructures. It remains to be answered, however, that which of these factors play a major control.

9 Quantitative analysis of growth rings and their applications on fossil conifer wood

GOU Xu-dong , FENG Zhuo

2021, 60(2):299-313. DOI: 10.19800/j.cnki.aps.2020063 CSTR:

[Abstract](430) [HTML](0) [PDF 0.00 Byte](0)

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Trees faithfully record the physiological responses to climatic and environmental changes during their life spans, which can be obtained by using quantitative analysis of the anatomical characteristics of growth rings. Thus, quanti-tative analysis of growth rings is widely used in modern forestry, geography, palaeoclimatology and palaeontology. In this paper, we systematically compared different parameters and methods of quantitative analysis of growth rings, in-cluding the identification of Growth Ring Type, Growth-ring Width, Annual Sensitivity, Mean Sensitivity, Ring Markedness Index, Percentage Latewood, Percentage Diminution, Vulnerability Index, Mesomorphy Index, and the cumulative algebraic sum of each cell's deviation from the mean of the radial diameters (CSDM). The application of these parameters and methods on fossil conifer wood not only provides an unique opportunity to assess the leaf lon-gevity and phenology of ancient conifer plants, but also provides comprehensive understandings of the palaeoenvi-ronmental and palaeoclimatic conditions during the geological past. Therefore, quantitative analysis of growth rings has irreplaceable advantages in the study of fossil conifer wood.

10 A brief analysis on the process and Penalty selection forconstructing the composite stratigraphic section using CONOP: a quantitative study on Late Devonian ammonites

CHEN Xiu-hua , JI Cheng

2021, 60(2):314-326. DOI: 10.19800/j.cnki.aps.2021003 CSTR:

[Abstract](387) [HTML](0) [PDF 0.00 Byte](0)

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Along with the research development on quantitative stratigraphy and paleontology, Constrained Optimization (CONOP) has played an important role in the quantitative analysis of paleontological taxa diversity changes and stratigraphic correlations. This paper briefly introduces the principles and algorithms of CONOP and the process of stratigraphic correlation analysis based on CONOP, which includes selection, standardization and input of stratigraphic data, constructing a composite section, and finally achieving the diversity curve. Using the Famennian ammonites as an example, we analyzed the influence of different Penalty selection (Penalty = “Interval” and Penalty = “Level”) on the event sequence and diversity level of fossils in the composite section. The results indicate that there is no significant difference on the event sequence and diversity of the composite section when the selected sections have very few conflicts on the event sequence the deposition of the sections is relatively thick and even, and the fossils are sufficiently sampled. If the sequence of events varies remarkably among different sections and the deposition of the sections is relatively thick and even, the Interval measurement method is recommended, because it is optimized according to the section thickness. If the sections have good fossil records and have been sufficiently sampled, the Level measurement method is recommended to avoid the bias caused by different deposition rates, as it is optimized based on the number of events.

Volume 60,Issue 2,2021 Table of Contents

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