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  • First discovery of dinosaur eggs in Nanhu Gebi of Hami, Xinjiang Uygur Autonomous Region of China

    分类: 生物学 >> 动物学 提交时间: 2022-08-02 合作期刊: 《古脊椎动物学报》

    摘要:报道了哈密南湖戈壁首次发现的恐龙蛋,包括长形长形蛋(Elongatoolithus elongatus)和椭圆形蛋未定种(Ovaloolithus oosp.)。这些恐龙蛋的发现不仅扩展了长形蛋类和椭圆形蛋类的古地理分布,而且表明南湖戈壁含蛋岩层地质时代为晚白垩世末期;该地层是否可与吐鲁番盆地的苏巴什组进行对比还有待进一步工作确认

  • 八种红树植物幼苗的叶片可溶性蛋白和抗氧化酶活性对光强的响应

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-07-05 合作期刊: 《广西植物》

    摘要:红树林湿地生态系统的恢复与重建是我国南方海岸带生态恢复研究的重点领域之一。然而,红树林群落的人工恢复和改造首先需要关注的是如何进行红树种类的空间配置,这需要明确红树植物光适应的生理生态策略,为人工红树林群落的优化配置提供理论指导。该文选取无瓣海桑(Sonneratia apetala)、秋茄(Kandelia candel)、木榄(Bruguiera gymnorrhiza)、桐花树(Aegiceras corniculatum)、老鼠簕(Acanthus ilicifolius)、卤蕨(Acrostichum aureum)、银叶树(Heritiera littoralis)和黄槿(Hibiscus tiliaceus)为研究对象,通过遮荫控制试验,研究这8种红树植物一年生幼苗在不同光照强度(自然光强的100%、45%、30%、10%)下的叶片可溶性蛋白含量和抗氧化酶活性的响应特征。结果表明:(1)随光照强度下降,木榄、老鼠簕和卤蕨的叶片可溶性蛋白含量受到的影响较小,无瓣海桑、秋茄、桐花、银叶树和黄槿的叶片可溶性蛋白含量则表现出下降趋势。(2)木榄、老鼠簕和卤蕨的SOD和APX等抗氧化酶活性在10%光照强度处理下的活性与对照并无显著差异,无瓣海桑、秋茄、桐花树、银叶树和黄槿的抗氧化酶活性总体呈下降趋势。以上结果说明,从对光照的生理适应角度来看,木榄、老鼠簕和卤蕨具有一定耐阴性,适宜种植在光照条件稍弱的林下;无瓣海桑、秋茄、桐花树、银叶树和黄槿适宜作为中上层树种或在郁闭度较低的林下种植。

  • 生物钟PRR蛋白促进拟南芥幼苗中花青素的合成

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-07-05 合作期刊: 《广西植物》

    摘要:生物钟(circadian clock)是激发植物生理特征节律性表达并使之维持稳定的保守内源调节机制。PRR(PSEUDO-RESPONSE REGULATOR)蛋白家族是生物钟中央振荡器的重要组分,调控植物种子萌发、下胚轴伸长和开花等多种生命过程。花青素(anthocyanins)是植物次生代谢产物,对植物的繁衍、生长发育和抵抗逆境胁迫有重要作用。该文以拟南芥(Arabidopsis thaliana)为研究对象,探讨生物钟PRR蛋白对花青素生物合成的调控功能和分子机制。结果表明:(1)在PRR基因单突变体及多突变体幼苗中,花青素的积累明显降低,并且某些花青素合成相关基因的表达显著降低。(2)相反,在PRR5过表达幼苗中,花青素的积累以及某些花青素合成相关基因的表达显著升高。(3)蛋白相互作用实验结果表明,PRR5蛋白能与MYB75、TT8、MYB90及MYB113等花青素调控蛋白相互作用形成复合物。(4)遗传学分析结果表明,拟南芥PRR5诱导幼苗中花青素的合成依赖于MYB家族花青素调控蛋白。综上所述,生物钟PRR蛋白可能通过PRR5与MYB75、TT8等相互作用促进拟南芥幼苗中花青素的合成和积累。

  • 牛油果果实发育过程中营养物质含量变化研究

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-07-05 合作期刊: 《广西植物》

    摘要:为了确定牛油果的最佳采收期,该文采用电感耦合等离子体发射光谱法、灼烧法、茚三酮柱后衍生离子交换色谱法、回流提取法和GC-MS联用技术,研究了‘HASS’、‘V3’和‘V4’等3个品种牛油果果实中粗脂肪、氨基酸、矿质元素以及灰分在6—12月间的含量变化,以阐明牛油果生长发育过程中营养物质的累积变化规律。结果表明:(1)3个品种牛油果中油脂的主要成分均为油酸,其中,‘HASS’和‘V4’果实中的粗脂肪含量在12月份达到峰值,‘V3’的则在10月份即达到峰值,之后有所下降。(2)3个品种牛油果中均含有17种氨基酸,包括7种人体必须氨基酸、2种儿童必须氨基酸以及8种人体非必须氨基酸,其中,‘HASS’和‘V3’果实中的17种氨基酸含量在11月达到峰值,而V4的则在10月份即达到峰值。(3)3个品种牛油果中均含有P、K、Ca、Mg、Zn、Fe、Mn、Cu、Na等9种矿质元素,其中,P、K、Zn、Fe、Na含量在10—12月累积至最大,其余4种矿质元素变化规律不明显。(4)灰分含量变化规律与粗脂肪相似。研究表明,3个品种牛油果的营养物质均在10月份即达到最佳值,可根据需求进行采收。

  • 大学生新冠疫情心态认知量表的编制与检验

    分类: 心理学 >> 应用心理学 提交时间: 2022-07-05

    摘要:新冠疫情发生后,大学生生活发生了巨大的改变。因为政策的不断调整,封校、封寝、交往与休闲活动被限制,大学生情绪出现了波动。这种复杂的情绪反应,传统的量表都不能完全反应出其忽高忽低的反复性情绪。大学生属于群体生活,心态具有社会和群体属性,其形成和变化涉及多种因素。它不是个人心态的简单累积和机械叠加。民众心理健康测量(DASS)更倾向于负性情绪严重时的测量,不能完全表达疫情好转时的“积极”心态。SCL-90(90症状清单),SDS(抑郁状态量表)都更倾向于个体测量,而非民众风险认知及其心理行为研究。我们经过研究,编制新冠疫情下心态认知量表并检验。我们的研究对于疫情下民众的心态认知有着积极的意义。只有掌握民众的心态变化,才能开展针对性心理疏导,助力打赢抗击疫情这场人民战争。

  • 发展性阅读障碍视听时间整合缺陷可能的机制:视听时间再校准能力受损

    分类: 心理学 >> 发展心理学 分类: 心理学 >> 教育心理学 提交时间: 2022-06-30

    摘要:发展性阅读障碍的本质一直是研究者争论的焦点。大量研究发现,阅读障碍者具有视听时间整合缺陷。然而,这些研究仅考察了阅读障碍者视听时间整合加工的整体表现,也就是平均水平的表现,却对整合加工的变化过程缺乏探讨。视听时间再校准反映了视听时间整合的动态加工过程,对内部时间表征与感觉输入之间差异的再校准困难则会导致多感觉整合受损,而阅读障碍者的再校准相关能力存在缺陷。因此,视听时间再校准能力受损可能是发展性阅读障碍视听时间整合缺陷的根本原因。未来的研究需要进一步考察发展性阅读障碍者视听时间再校准能力的具体表现,以及这些表现背后的认知神经机制。

  • OsIMA1 增强水稻对镉逆境的适应性

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-06-29 合作期刊: 《广西植物》

    摘要:铁(Fe)是植物生长发育所必需的营养元素而镉(Cd)是对植物有害的元素,且植 物对 Fe 和 Cd 的吸收存在拮抗作用。OsIMA 是一类正调控水稻 Fe 吸收的一类小肽,其过表 达可以促进 Fe 的积累。为探究 OsIMA 是否参与水稻对 Cd 胁迫的适应性,该研究以水稻为 研究材料,利用荧光定量PCR 分析了OsIMA 基因的表达水平,通过遗传转化和CRISPR/Cas9 基因编辑技术构建了 OsIMA1 过表达植物和 ima1 突变体植物,评估了 OsIMA1 过表达和突 变体植物在 Cd 逆境条件下的株高,并用利用电联耦合等离子体质谱法测量了根和地上部的 Fe 和 Cd 含量。结果表明:(1)Cd 处理后,OsIMA1 和 OsIMA2 的转录水平上调。(2)OsIMA1 过表达植物比野生型植物对 Cd 胁迫更耐受。(3)ima1 功能缺失突变体比野生型植物对 Cd 胁迫更敏感。(4)Cd 含量检测发现,OsIMA1 过表达植株根系的 Cd 含量较高,而 ima1 突 变体植株地上部的 Cd 含量较高。综上所述,OsIMA1 通过限制 Cd 从根向地上部的转运以 增强水稻对 Cd 逆境的适应能力,该研究为定向培育耐 Cd 作物提供了理论依据。

  • 一种用于空间VLBI的射电源条纹搜索算法

    分类: 天文学 >> 天文学 提交时间: 2022-06-28 合作期刊: 《天文研究与技术》

    摘要:

    我国探月工程嫦娥七号将构建由中继星上4.1m口径抛物面天线及地基射电望远镜组成的首个月地空间甚长基线干涉测量(Very Long Baseline Interferometry, VLBI)试验系统。不同于地基甚长基线干涉测量望远镜,受中继星轨道扰动和设备时延影响,射电源预报时延模型和实际时延有时可能会有较大差异,导致无法引导VLBI相关处理机正常工作,需要通过射电源条纹搜索方法寻找实际时延模型才能解决这一问题。由于4.1m空间天线口径较小,接收信号能力弱。为提高信噪比,需要长时间积分,而线性时延模型无法保证长时间的时延精度。针对这一问题,提出了一种用于空间甚长基线干涉测量的射电源条纹搜索算法,首先通过建立时延和时延率的二维搜索网格,使用每个网格点对应的先验时延和时延率构建线性时延模型;再使用该线性时延模型对原始数据分时段相关处理;然后采用二维傅里叶变换搜索残余时延和时延率,确定最大的相关幅度值对应的网格点;最后使用该网格点的先验时延和时延率以及残余时延和时延率重构二次项时延模型。通过对RadioAstron空间甚长基线干涉测量的地空基线实际数据处理,验证了该射电源条纹搜索算法的正确性。

  • 一种用于空间VLBI的射电源条纹搜索算法

    分类: 天文学 >> 天文学 提交时间: 2022-06-24 合作期刊: 《天文研究与技术》

    摘要:

    我国探月工程嫦娥七号将构建由中继星上4.1m口径抛物面天线及地基射电望远镜组成的首个月地空间VLBI试验系统。不同于地基VLBI望远镜,受中继星轨道扰动和设备时延影响,射电源预报时延模型和实际时延有时可能会有较大差异,导致无法引导VLBI相关处理机正常工作,需要通过射电源条纹搜索方法寻找实际时延模型才能解决这一问题。由于4.1m空间天线口径较小,接收信号能力弱。为提高信噪比,需要长时间积分,而线性时延模型无法保证长时间的时延精度。针对这一问题,本文提出了一种用于空间VLBI的射电源条纹搜索算法,首先通过建立时延和时延率的二维搜索网格,使用每个网格点对应的先验时延和时延率构建线性时延模型;再使用该线性时延模型对原始数据分时段相关处理;然后采用二维傅里叶变换搜索残余时延和时延率,确定最大的相关幅度值对应的网格点;最后使用该网格点的先验时延和时延率以及残余时延和时延率重构二次项时延模型。通过对RadioAstron空间VLBI的地空基线实际数据处理,验证了该射电源条纹搜索算法的正确性。

  • Commissioning of Laser Electron Gamma Beamline SLEGS at SSRF

    分类: 物理学 >> 核物理学 提交时间: 2022-06-13

    摘要:

    Shanghai Laser Electron Gamma Source (SLEGS) is a powerful gamma source to provide MeV gamma-ray beams for nuclear science and technology. It is developed as one of the sixteen beamline stations in Phase II Project of the Shanghai Synchrotron Radiation Facility (SSRF). The slant-scattering mode is for the first time systematically employed in the laser Compton scattering (LCS) at SLEGS to produce energy-tunable quasi-monoenergetic gamma-ray beams.  SLEGS officially completed its commissioning from July to December 2021. Gamma-rays in energy range of 0.25 - 21.7 MeV with the flux of 2.1 × 104 - 1.2 × 107 photons/s and the energy spread of  2 – 15 % are produced during the test. This paper reports results of the commissioning of the SLEGS beamline.

  • 运算动量效应的理论解释及其发展性预测因素

    分类: 心理学 >> 发展心理学 提交时间: 2022-06-13

    摘要:

    了解运算偏差的形成与发展对探索算数运算系统的内在机制具有重要意义,早期的算数运算能力是儿童理解和进行复杂数学运算的基础。运算动量偏差是指个体在进行基本数学运算时倾向于高估加法运算结果而低估减法运算结果的一种运算偏差,主要包括三种理论解释,即注意转移假说、启发式解释和压缩解释。鉴于运算动量效应在成年群体中的相对稳定性以及在不同发展阶段儿童中发现的不一致证据,数学能力的提高与空间注意的成熟可结合不同的理论解释来阐明儿童发展过程中运算动量效应的变化趋势。未来可以进一步整合多种研究任务以揭示运算动量效应的发展轨迹,考察数量表征系统与运算动量效应间的关联,探究运算动量效应在不同运算符号中的稳定性,探讨不同因素共同作用对运算动量效应的影响,并设计有关数学能力的干预措施以减少运算动量效应这一运算偏差。

  • On kannemeyeriiform dicynodonts from the Shaanbeikannemeyeria Assemblage Zone of the Ordos Basin, China

    分类: 生物学 >> 动物学 提交时间: 2022-06-07 合作期刊: 《古脊椎动物学报》

    摘要:Shaanbeikannemeyeria is a common tetrapod from the lower part of the Ermaying Formation of the Ordos Basin, China. There are taxonomical questions surrounding this genus, such as the validity of the genus, and how many species are included within it. Several specimens have been collected since 1978. Shaanbeikannemeyeria first appeared from the top of the Heshanggou Formation. These specimens are described to clarify the diagnostic characters, the individual variations and the phylogenetic position of Shaanbeikannemeyeria. Only one species, S. xilougouensis, is recognized. It is characterized by the following autapomorphies: occiput strongly inclined relative to the palate such that the skull is much shorter basally than dorsally, sword tip-like premaxillary posterodorsal processes, tall and dorsally-convex cutting blade on the medial edge of the dorsal surface of the dentary, reflected lamina with a separated posteroventral process, and 15 dorsal vertebrae. This species shows variations on the cranial morphology, such as the occiput height relative to the width, the snout tip (sharp or obtuse), the shape of the orbital portion of the zygomatic arch, and the shape of caniniform process. Some variations could be ontogenetically related, such as the development of the caniniform process and tusk, the posterior extension of the maxilla on the zygomatic arch, the distance between the frontal and the premaxilla, the intertemporal bar width, and the exposing degree of the parietals. Based on postcranial bones, the second dicynodont genus (possibly Parakannemeyeria) is present in the lower Ermaying Formation.

  • 拟南芥bHLH Ib 转录因子调控FIT 的转录

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-06-07 合作期刊: 《广西植物》

    摘要:FIT 是调控拟南芥铁稳态的一个关键调控因子,它在转录水平受到缺铁诱导,但是背 后的调控机制还不甚清楚。该研究以拟南芥bHLH38 和FIT 的单、双过表达植物及 bHLH Ib 四突变体为研究材料,进行了缺铁处理实验,并通过定量 PCR 分析了FIT 的转录水平。结果 表明:(1)在铁充足时,bHLH38 过表达植物中FIT 的转录水平显著高于其在野生型中水平; (2)在 bHLH Ib 四突变体里FIT 的转录水平不受缺铁诱导;(3)FIT 单过表达不能激活内 源FIT 的转录,但bHLH38 和FIT 的双过表达则可以激活内源FIT 的转录;(4)在缺铁条件 下,所有植物中FIT 的转录水平均与野生型中的FIT 水平无明显差异。基于以上结果,该研 究认为 bHLH Ib 转录因子是缺铁诱导FIT 转录的必要条件,而非充分条件。

  • Projection of hydrothermal condition in Central Asia under four SSP-RCP scenarios

    分类: 地球科学 >> 地理学 提交时间: 2022-05-30 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Hydrothermal condition is mismatched in arid and semi-arid regions, particularly in Central Asia (including Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Turkmenistan), resulting many environmental limitations. In this study, we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles (MMEs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) under four Shared Socioeconomic Pathway and Representative Concentration Pathway (SSP-RCP) scenarios (SSP126 (SSP1-RCP2.6), SSP245 (SSP2-RCP4.5), SSP460 (SSP4-RCP6.0), and SSP585 (SSP5-RCP8.5)) during 2015–2100. The bias correction and spatial disaggregation, water-thermal product index, and sensitivity analysis were used in this study. The results showed that the hydrothermal condition is mismatched in the central and southern deserts, whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition. Compared with the historical period, the matched degree of hydrothermal condition improves during 2046–2075, but degenerates during 2015–2044 and 2076–2100. The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions. The result suggests that the optimal scenario in Central Asia is SSP126 scenario, while SSP585 scenario brings further hydrothermal contradictions. This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.

  • Spatiotemporal changes of typical glaciers and their responses to climate change in Xinjiang, Northwest China

    分类: 地球科学 >> 地理学 提交时间: 2022-05-30 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes. In this study, we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990–2015 in 4 different mountainous sub-regions in Xinjiang Uygur Autonomous Region of Northwest China: the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains; the Yinsugaiti Glacier sub-region in the Karakorum Mountains; and the Youyi Peak sub-region in the Altay Mountains. The standardized snow cover index (NDSI) and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to 2015. Glacial areas in the Bogda Peak, Karlik Mountain, Yinsugaiti Glacier, and Youyi Peak sub-regions in the period of 1990–2015 decreased by 57.7, 369.1, 369.1, and 170.4 km², respectively. Analysis of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the origin. Glacier area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect, while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south aspect. Increased precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain extent. However, glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased precipitation. On a seasonal time scale, glacier area changes in the Bogda Peak, Karlik Mountain, Yinsugaiti Glacier, and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season; on an annual time scale, the correlation coefficient between glacier area and annual average temperature was –0.72 and passed the significance test at P<0.05 level in the Karlik Mountain sub-region. The findings of this study can provide a scientific basis for water resources management in the arid and semi-arid regions of Northwest China in the context of global warming.

  • 基于概率霍夫变换的太阳射电Ⅲ和Ⅱ型暴自动识别及参数提取

    分类: 天文学 >> 天文学 提交时间: 2022-05-30 合作期刊: 《天文研究与技术》

    摘要:

    耀斑和日冕物质抛射(Coronal Mass Ejection,CME)期间产生的非热高能粒子流和激波是产生灾害性空间天气事件的两种主要因素,它们主要观测特征分别是具有快速频率漂移特征的射电Ⅲ型暴和具有较为缓慢频率漂移的射电Ⅱ型暴。本文主要介绍了使用概率霍夫变换(Probabilistic Hough Transform)的方法,在观测数据中自动识别出太阳射电Ⅲ型暴和Ⅱ型射电暴,并提取射电Ⅲ和Ⅱ型暴的特征参数,最后利用识别出的射电Ⅱ型暴的物理参数估计了CME激波的速度。

  • 云南被子植物菊类分支的系统发育多样性及其分布格局

    分类: 生物学 >> 植物学 >> 应用植物学 提交时间: 2022-05-21 合作期刊: 《广西植物》

    摘要:全球气候变化与人为活动等因素导致的生物多样性丧失,引起了全球各界对生物多样性保护的高度关注。传统生物多样性保护主要对物种、特有种、受威胁物种的种类组成及其分布模式开展研究,忽视了进化历史在生物多样性保护中的作用。云南是全球生物多样性热点地区的交汇区,生物多样性的保护历来受到广泛关注,为了更好地探讨云南生物多样性的保护措施,该研究以云南被子植物菊类分支物种为研究对象,基于物种间的演化关系,结合其地理分布,从进化历史的角度探讨物种、特有种、受威胁物种的种类组成及系统发育组成的分布格局,并整合自然保护地的空间分布,识别生物多样性的重点保护区域。结果表明:云南被子植物菊类分支的物种、特有种及受威胁物种的物种密度与系统发育多样性均显著正相关;由南向北,标准化系统发育多样性逐渐降低;云南南部、东南部、西北部是云南被子植物菊类分支的重点保护区域,加强这些区域的保护,将最大化地保护生物多样性的进化历史和进化潜能。由此可见,融合进化历史信息的植物多样性格局分析不仅有助于更加深入地理解植物多样性的形成与演变,也为生物多样性保护策略的制定提供更多的思路。

  • Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:A new genus and species of the family Eugaleaspidae (Eugaleaspiformes, Galeaspida), Xitunaspis magnus gen. et sp. nov., is described from the Lower Devonian Xitun Formation in Qujing, Yunnan Province, China. The new genus displays the diagnostic characters of the Eugaleaspidae, including a slit-like median dorsal opening, no inner cornual process, developed median dorsal canals, and only three pairs of lateral transverse canals extending from lateral dorsal canals. Different from the other eugaleaspids, X. magnus possesses a large headshield with thick dermal bone and a more plesiomorphic sensory canal system. The phylogenetic analysis of the Galeaspida reveals that Xitunaspis clusters with Dunyu and Eugaleaspis to form a monophyletic clade Eugaleaspidae Liu, 1965, and has a closer relationship with Dunyu than Eugaleaspis by sharing the thick dermal bone of the headshield. The new finding represents the first convincing fossil record of the Eugaleaspiformes in the middle Lochkovian Xitun Formation and adds to our knowledge about the morphology of eugaleaspiforms and the evolutionary pattern of the sensory canal system in the Eugaleaspiformes and even Galeaspida.

  • New fossils of small and medium-sized bovids from the Early Pleistocene Site of Shanshenmiaozui in Nihewan Basin, North China

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:Shanshenmiaozui site in Nihewan Basin in North China is a recently discovered Early Pleistocene site which yields rich and diverse mammalian fossils. In the fauna, the small and medium-sized bovid fossils are well represented and can be referred to the following taxa: Spirocerus wongi, Gazella sinensis, Ovis shantungensis and Megalovis piveteaui respectively, among which G. sinensis is the dominate species. S. wongi and G. sinensis are mainly represented by horn-cores and partial skull bones as well as mandibles; in addition, metacarpal and/or metatarsal bones were also recognized for all of the four species. The horn-cores are easy to be identified to the species level, while the dentitions and the postcranial bones underwent a series of examinations and comparisons before getting properly determined and referred to the most approximate taxa. Among the postcranial bones, the metapodials, especially to the metacarpal bones special attentions were paid, which are crucial not only for taxonomic identification, but also for phylogenetic and paleoecological reconstructions; the previously misidentified metapodial specimens in Nihewan fauna were reconsidered in this paper. In the SSMZ fauna, the bovid guild is dominated by Gazella and Bison, which indicates steppe was the most important biome in Nihewan Basin during Early Pleistocene.

  • Attributing “Gomphotherium shensiense” to Platybelodon tongxinensis, and a new species of Platybelodon from the latest Middle Miocene

    分类: 生物学 >> 动物学 提交时间: 2022-04-16 合作期刊: 《古脊椎动物学报》

    摘要:Platybelodon is the predominant proboscidean of northern China’s Middle Miocene. However, the cranial and cheek tooth morphologies are not clearly diagnosed. In particular, the differential diagnoses between Platybelodon and Gomphotherium have not been comprehensively examined. Here we restudied the cranium previously identified as Gomphotherium shensiense. The upper tusks lack an enamel band, the rostrum is long and narrow, the facial part is rostrally positioned, and a large “prenasal slope” is present. These characters are distinct from those of any species of Gomphotherium, but fit well with some primitive species of Platybelodon, i.e., P. tongxinensis and P. danovi. The molars are also close to the type specimen of P. tongxinensis in the tetralophodont M3 with mesiodistally wide interlophs, curved outline, and a tendency of cementodonty. In this article, we synonymized Gomphotherium shensiense with P. tongxinensis. Moreover, we recognized a new species, Platybelodon tetralophus, from the P. grangeri material collected by the AMHN expedition in Tunggur region. Platybelodon tetralophus differs from P. grangeri and the other species in the tetralophodont M2 and m2, representing the most derived species within Platybelodon. It has only occurred in the uppermost horizon of the Tunggur Formation, i.e., the Tamuqin Fauna (Platybelodon Quarry and Wolf Camp Quarry of AMHN). This work is a comprehensive amending of the genus Platybelodon.