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1. chinaXiv:202111.00034 [pdf]

Revisit of Hsianwenia wui (Cyprinidae: Schizothoracinae) from the Pliocene of Qaidam Basin

BI Dai-Ran; WU Fei-Xiang; WANG Ning; CHANG Mee-Man; FANG Geng-Yu
Subjects: Biology >> Zoology

The Qaidam Basin is a key area for understanding the paleoenvironmental and faunal history of the Tibetan Plateau. The fossil schizothoracine fish, Hsianwenia wui, evolved extraordinarily thickened bones to adapt to the aridification of the Qaidam Basin during the Pliocene. However, the nature of the bone thickening itself remains elusive. To promote the further investigation of the physiological mechanism of the pachyostosis and the phylogenetic interrelationships of Hsianwenia and all relevant cyprinids, here we present a comprehensive morphological study of Hsianwenia. We have new information on the anterior part of the cranial cavity, a large supraneural 3 in the Weberian apparatus, numerous procurrent caudal fin rays supported by the preural centrum (Pu) 5, and a neural arch on Pu2. We also find the differentiated pattern of the bone-thickening: the pachyostosis exists in the endoskeleton but not in the dermal skeleton; it is more obvious in ventral bones than in dorsal ones, when the thickening is present in the dorsally and ventrally grouped endoskeletal bones (e.g., the epineural and epipleural intermuscular bones). Considering the integrity of musculoskeletal system manipulating the chewing activities, we suspect that the thickened pharyngeal jaws and the hard food processing might be associated with the unique hind protrusion (cleithral “humeral” process) of the dermal pectoral girdle of Hsianwenia.

submitted time 2021-11-26 From cooperative journals:《古脊椎动物学报》 Hits31Downloads8 Comment 0

2. chinaXiv:202111.00035 [pdf]

A revision of the eggshell fragment of Spheroolithus megadermus from Laiyang, Shandong Province, China

ZHANG Shu-Kang
Subjects: Biology >> Zoology

In 1958, a special type of dinosaur egg was discovered in Zhaotuan, Laiyang, Shandong Province, China. Although only a large eggshell fragment was collected, its extremely large thickness indicated that the eggshell fragment represented a new ootaxon. In previous studies, it was named Spheroolithus megadermus and assigned to the oogenus Spheroolithus under the oofamily of the Spheroolithidae based on the microstructure in radial view. However, a comparative study of the microstructure in tangential views between the large eggshell fragment from Laiyang and the recently reported Multifissoolithus from Zhejiang Province, China and Yamaguchi, Japan revealed that all of them have roughly paralleled and wavy clefts. Therefore, this study reassigned the large eggshell fragment from Laiyang to Multifissoolithus of the Dongyangoolithidae and discussed its unique compact layer near the eggshell’s inner surface, as well as the chronological and spatial distribution of dongyangoolithid eggs. The reassignment of the holotype of Spheroolithus megadermus also indicates that the referred specimen of Spheroolithus megadermus from Changtu, Liaoning Province becomes the holotype of a new oospecies Spheroolithus quantouensis.

submitted time 2021-11-26 From cooperative journals:《古脊椎动物学报》 Hits20Downloads8 Comment 0

3. chinaXiv:202111.00036 [pdf]

A new aardwolf-line fossil hyena from Middle and Late Miocene deposits of Linxia Basin, Gansu, China

Henry GALIANO; Z. Jack TSENG; Nikos SOLOUNIAS; WANG Xiao-Ming; QIU Zhan-Xiang; Stuart C. WHITE
Subjects: Biology >> Zoology

The aardwolf Proteles cristatus is the only known hyaenid, living or extinct, to exhibit an extremely reduced dentition related to its termite-specializing diet. The fossil record of extant aardwolves extends to 2 to 4 million years ago, but records that inform its evolutionary origins are essentially nonexistent. Such circumstance renders it difficult to place this unusual hyena in the broader evolutionary context of small-bodied hyaenid species in Eurasian Neogene deposits. Here we describe a new genus and species of a small-bodied hyaenid, Gansuyaena megalotis, representing the closest morphological link to aardwolves to date. This new fossil hyena is based on a skull with associated mandible, a rostrum preserving several teeth, and several referred specimens. The new specimens were discovered in Neogene deposits in Linxia Basin, Gansu Province, China. Phylogenetic analysis indicates that among early hyaenids, G. megalotis is most closely related, but unlikely ancestral, to the living aardwolf. Also recognized in this new species are the fossils previously referred to “Protictitherium” aff. P. gaillardi from Pasalar, Turkey. Additionally, “Plioviverrops” guerini from Los Mansuetos, Spain is interpreted to represent a second Gansuyaena species. In addition to the living aardwolf, Proteles cristatus, our analyses suggest that the proteline lineage includes the extinct genera Gansuyaena, Mesoviverrops, and Plioviverrops. Although the precise timing and geographic location of evolutionary divergence between the aardwolf and Gansuyaena remain elusive, critical new morphological information provided by Gansuyaena specimens reinforce findings from recent genomic analyses that the aardwolf lineage has an ancient origin from small-bodied stem hyaenids prior to the appearance of large and robust bone-cracking hyaenines.

submitted time 2021-11-26 From cooperative journals:《古脊椎动物学报》 Hits17Downloads6 Comment 0

4. chinaXiv:202110.00032 [pdf]


Subjects: Biology >> Ecology

灌丛沙堆在维持草地生态功能和土地沙漠化过程中扮演着非常重要角色。浑善达克沙地 分布着众多灌丛沙堆,其中以锦鸡儿属(Caragana)灌丛沙堆最为典型。选择不同沙漠化程度(轻 度沙漠化、中度沙漠化、重度沙漠化、严重沙漠化)沙地上的锦鸡儿属灌丛沙堆,进行野外调查和灌 丛沙堆形态指标测量,对比不同沙漠化程度沙地上锦鸡儿属灌丛沙堆的形态特征,分析灌丛和沙 堆形态参数间的关系及其影响因子。结果表明:(1)不同沙漠化程度沙地灌丛沙堆大小不同,总体 表现为灌丛沙堆规模从严重沙漠化、重度沙漠化、中度沙漠化到轻度沙漠化逐渐减小的特点,轻度 和中度沙漠化沙地的灌丛沙堆形态在水平面上的垂直投影类似椭圆形、形状类似半椭圆球体,重 度和严重沙漠化沙地的灌丛沙堆形态在水平面上的垂直投影类似不规则棱形、形状类似四棱锥 体,沙堆形态的主要影响因素可能与沙源丰富度有关。(2)不同沙漠化程度沙地上的锦鸡儿属灌丛 的各形态参数呈显著相关,重度和严重沙漠化沙地上的锦鸡儿属灌丛沙堆形态参数间的相关系数 比中度和轻度的更高,总体上灌丛沙堆长轴、短轴和沙堆高度之间协同发展。(3)轻度和中度沙漠 化沙地上的锦鸡儿属灌丛沙堆的长轴、短轴与高度间呈幂函数关系,表明灌丛沙堆还存在较大发 展空间,重度和严重沙漠化沙地上灌丛沙堆的长轴、短轴与高度间呈二次函数关系,表明灌丛沙堆 已经发育成熟,且易因根系水分供应不足等导致灌丛向衰亡方向发展。

submitted time 2021-10-10 From cooperative journals:《干旱区地理》 Hits4228Downloads191 Comment 0

5. chinaXiv:202110.00033 [pdf]


Subjects: Biology >> Ecology

灌丛群落作为祁连山森林生态系统的重要组成部分,在维护西北地区生态安全方面扮演着 不可或缺的角色。系统地研究祁连山地区灌丛群落结构特征对阐明灌丛群落的更新、演替和稳定 具有十分重要的意义,可为祁连山区森林生态系统的保护、恢复与重建提供基础数据和科学依 据。选择分布在祁连山大野口流域的甘青锦鸡儿(Caragana tangutica)、鲜黄小檗(Berberis diapha? na)、金露梅(Potentilla fruticosa)、鬼箭锦鸡儿(Caragana jubata)和吉拉柳(Salix gilashanica)5 种典 型灌丛群落为研究对象,通过野外调查取样和室内分析,主要研究了 5 种典型灌丛群落的物种组 成、生活型组成和物种多样性的变化规律。结果表明:(1)祁连山大野口流域灌丛群落组成较为简 单,只出现了 48 种植物,隶属于 26 科,38 属,以蔷薇科、禾本科、菊科和豆科等西北干旱区优势科的 数量居多。(2)生活型谱均以地面芽植物所占比例最大,为 37.09%,地上芽植物所占比例最少,为 4.00%。(3)整体上看,灌丛群落的 Shannon-Wiener 多样性指数(H)变化范围为 1.12~2.26,Simpson 多样性指数(D)变化范围为 0.60~0.74,其物种多样性指数较低,物种组成较为简单,其中不同灌丛 群落 H 多样性指数表现为金露梅>鬼箭锦鸡儿>鲜黄小檗>甘青锦鸡儿>吉拉柳,D 多样性指数表现 为金露梅>鬼箭锦鸡儿>吉拉柳>鲜黄小檗>甘青锦鸡儿。(4)不同的生境条件导致群落多样性层间 结构存在差异,除鬼箭锦鸡儿群落,多样性指数均为草本层>灌木层,而鬼箭锦鸡儿群落中灌木层 和草本层的物种多样性指数较为接近,物种组成灌草均一。

submitted time 2021-10-10 From cooperative journals:《干旱区地理》 Hits5051Downloads471 Comment 0

6. chinaXiv:202109.00029 [pdf]


Subjects: Biology >> Botany

采用培养皿法研究不同类型钠盐胁迫对荒漠植物盐爪爪种子萌发率、萌发指数、幼苗芽长和根长,分析盐爪爪种子萌发与幼苗生长适应不同类型盐碱地的机制,为种植盐爪爪生态修复不同类型盐碱地提供了科学依据。结果表明:(1)NaCl、Na2SO4、NaHCO3、Na2CO3均显著抑制盐爪爪种子的萌发率和萌发指数。(2)回归方程分析盐爪爪萌发期的耐NaCl、Na2SO4、NaHCO3、Na2CO3临界值分别为325 mmol·L-1、267 mmol·L-1、245 mmol·L-1 和166 mmol·L-1,其极限值分别是671 mmol·L-1、580 mmol·L-1、569 mmol·L-1和389 mmol·L-1,相对于中性盐,盐爪爪种子萌发时对碱性盐更敏感。(3)NaCl、Na2SO4、NaHCO3、Na2CO3均显著抑制盐爪爪幼苗芽和根的生长,盐爪爪种子萌发和幼苗生长对这4种钠盐的响应差异显著;相对于幼苗芽,幼苗根的响应更为敏感,可将根长作为评价盐爪爪耐盐性的参数,碱性盐毒害强于中性盐;根据盐分对盐爪爪种子萌发和幼苗生长的毒害性顺序依次为:NaCl<Na2SO4<NaHCO3<Na2CO3。

submitted time 2021-09-14 From cooperative journals:《干旱区研究》 Hits4911Downloads550 Comment 0

7. chinaXiv:202109.00030 [pdf]


Subjects: Biology >> Ecology

对新疆额尔齐斯河流域5种主要杨树天然林生物量和器官养分含量分析表明:5种杨树叶片平均N含量为19.36 g·kg-1,平均P含量为2.89 g·kg-1,叶片N含量接近全球和国内陆地植物水平,叶片P含量较高于全球和国内陆地植物平均水平;叶片平均N:P比值为6.83,相对较低于全球和国内陆地植物叶片N:P比值平均水平;叶片N:P比值高于茎干,茎干高于根系。额尔齐斯河杂交杨的叶片K含量最高,苦杨的茎干K含量最高,银白杨的根系K含量最高。5种杨树天然林生物量分布比,即苦杨:额尔齐斯河杂交杨:银灰杨:欧洲黑杨:银白杨为1:1.03:1.15:1.23:1.37,银白杨的生物量分布最高,苦杨的生物量分布最低。

submitted time 2021-09-14 From cooperative journals:《干旱区研究》 Hits4933Downloads234 Comment 0

8. chinaXiv:202109.00031 [pdf]


Subjects: Biology >> Botany


submitted time 2021-09-14 From cooperative journals:《干旱区研究》 Hits4807Downloads254 Comment 0

9. chinaXiv:202109.00032 [pdf]


Subjects: Biology >> Botany

植物根系水力再分配(Hydraulic Redistribution,HR)指水分在根-土界面水势梯度的驱动下,经由植物根系在土壤不同部位之间的被动传输过程。它是植物根系为了适应土壤水分的空间异质性而形成的一种生理调节对策,不仅能够优化植物对水分的利用,而且对生态系统的地球化学循环过程具有一定影响。因此,开展水分限制环境下HR的研究对深入理解干旱区植物生存的生态水文学机理及其调控对策具有重要的意义。基于此,本文通过回顾和分析HR国内外的最新研究动态及进展,分别从HR的发展历程、在生态水文中的作用、量的大小、普遍性和影响因素进行较为系统的评述。利用数据挖掘在全球尺度上对HR定量化描述,发现HR主要发生在较干旱的乔木植物群落中。此外,HR占蒸腾比例介于3%~79%,平均值为32%;从气候因子、植被特征、土壤特性等方面重点讨论了HR的影响因素,发现干燥指数和土壤质地显著影响HR的量(P<0.05)。最后,结合全球变化背景下HR面临的新挑战,提出了当前HR研究面临的难点问题及其在生态水文效应中应重点关注的科学前沿问题。本研究为今后HR的研究提供了一定的借鉴。

submitted time 2021-09-14 From cooperative journals:《干旱区研究》 Hits2825Downloads231 Comment 0

10. chinaXiv:202109.00033 [pdf]


Subjects: Biology >> Ecology

为探讨植被对环境变化的响应,采用2000—2019年MOD09A1遥感影像数据,利用最大值合成法、Mann-Kendall、Hurst趋势分析、水热配合分析等方法对准噶尔盆地植被动态变化及相关因素进行了分析。结果表明:受区域气候暖湿化、冷季降水增加及滴灌技术普及的影响,近20 a来准噶尔盆地植被整体呈增加趋势,增加区面积各季节平均占比为85.47%,减少区面积平均占比为12.61%。局部地势低洼易于积水、聚盐的区域植被表现为减少趋势。植被指数与盐渍化指数相关性分析表明两者呈负相关关系。绿洲区域植被变化主要受人类活动调控。Hurst趋势预测结果表明,盆地植被未来变化趋势方向与近20 a变化趋势的方向基本保持一致。研究结果对全球变暖和人类活动背景下盆地各生境植物群落的演替规律及成因具有一定的参考价值。

submitted time 2021-09-14 From cooperative journals:《干旱区研究》 Hits3034Downloads226 Comment 0

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