IVPP-IR研究单元&专题: 古低等脊椎动物研究室

The pelvic morphology of Parayunnanolepis (Placodermi, Antiarcha) revealed by tomographic data

Sat, 01 Jul 2023 16:55:56 GMT

题名: The pelvic morphology of Parayunnanolepis (Placodermi, Antiarcha) revealed by tomographic data 作者: ZHU, You-An; WANG, Ya-Jing; QU, Qing-Ming; LU, Jing; ZHU, Min 摘要:

腰带部位的形态，以及腹鳍在最早的有颌脊椎动物中是否存在，是解答脊椎动物附肢如何起源的关键。我国云南曲靖下泥盆统西屯组中的西屯副云南鱼(Parayunnanolepis xitunensis)过去被描述为具有外骨骼和内骨骼的腰带。基于高精度CT数据重新描述了西屯副云南鱼正型标本的腰带部位形态。结果显示副云南鱼并没有像之前描述的那样，同时保存一对大的膜质腰带和对应内骨骼腰带，而是在腰带部位拥有三对成对的膜质骨片，以及一块较大的中线膜质骨片。这些成对的膜质骨片是平坦的，位于躯体腹面，区别于其他早期有颌类拥有背侧叶的膜质腰带。目前仍没有决定性证据证明副云南鱼是否具有内骨骼腰带。比较早期有颌类各大类群中腰带部位膜质骨骼形态，可以看到腰带部位同时存在成对和中线膜质骨片这一型式在这些大类群中也有发现，可能是有颌类的祖征。有颌类在早期演化中可能将腰带部位的膜质骨片整合入不同的功能结构单元中。

摘要:

The pelvic morphology, and whether the pelvic fin is present or absent in the earliest jawed vertebrates are key in interpreting the origin of vertebrate paired fins. Parayunnanolepis xitunensis, an antiarch placoderm from the Early Devonian of Yunnan, South China, was previously described to possess the earliest evidence of both dermal and endoskeletal pelvic girdles, presumably for the attachment of the pelvic fins. Here, we redescribe the pelvic region of the holotype based on high-resolution computed tomographic data. Instead of having two large plates previously designated as dermal pelvic girdles, Parayunnanolepis possesses three pairs of lateral pelvic plates, and one large oval median pelvic plate. The paired pelvic plates are flat ventral plates, and differ from other dermal pelvic girdles in lacking a dorsal extension. There is no definitive evidence for the presence of an endoskeletal pelvic girdle in Parayunnanolepis, although the possibility cannot be ruled out. A comparison of the dermal pelvic plates in various jawed stem-gnathostomes suggests the presence of both paired and median pelvic plates is shared by different lineages and might be plesiomorphic. The jawed stem-gnathostomes may have recruited the ventral dermal skeleton of the post-thoracic body into different functional units.

黔东北石阡地区志留纪地层新知: 来自坉坪剖面的证据

Sat, 01 Jul 2023 16:45:47 GMT

题名: 黔东北石阡地区志留纪地层新知: 来自坉坪剖面的证据作者: 王建华; 蔡家琛; 朱敏; 乔妥; 贾连涛; 赵文金摘要:

贵州东北石阡地区的志留系出露良好、化石丰富, 是华南志留系研究程度较高的经典区域之一。本文报道在该地区志留系经典剖面——雷家屯剖面以北新揭露的坉坪剖面。坉坪剖面上的志留系兰多维列统自下而上依次为“龙马溪组”、香树园组、雷家屯组、马脚冲组、溶溪组、秀山组和迴星哨组, 可分别与其层型剖面进行良好对比, 且沉积连续、化石丰富, 特别是在溶溪组中部首次发现中国志留系中最低的含鱼化石层位。经过详细的地层、古生物、碳稳定同位素地层学等研究, 在理清坉坪剖面志留纪地层的沉积、化石特征及序列的基础上, 本文首次揭示该剖面志留系兰多维列统δ13Ccarb的连续变化曲线, 并在香树园组、雷家屯组和秀山组中识别出3次全球性δ13Ccarb事件——早埃隆事件(Early Aeronian Event)、晚埃隆事件(Late Aeronian Event)和瓦勒古事件(Valgu Event), 同时结合前人的研究成果, 探讨了石阡地区志留纪的沉积环境演变。

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

Sat, 01 Jul 2023 16:34:53 GMT

题名: Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan 作者: SUN, Hao-Ran; GAI, Zhi-Kun; CAI, Jia-Chen; LI, Qiang; ZHU, Min; ZHAO Wen-Jin 摘要:

记述了采自云南曲靖下泥盆统西屯组中的真盔甲鱼科一新属种——硕大西屯鱼(Xitunaspis magnus gen. et sp. nov.)。新属具有真盔甲鱼科的典型特征,包括一个纵长裂隙状的中背孔、没有内角、发达的中背管以及只有3对从侧背管上伸出的侧横管等,但其具有大而厚的头甲以及更原始的感觉管系统等特征明显区别于其他真盔甲鱼类。系统发育分析表明,西屯鱼属(Xitunaspis)与盾鱼属 (Dunyu)和真盔甲鱼属(Eugaleaspis)共同组成一个单系类群——真盔甲鱼科支系(Eugaleaspidae Liu, 1965), 并且三者之间西屯鱼与盾鱼的亲缘关系更为密切。作为曲靖地区下泥盆统西屯组中确凿的真盔甲鱼类化石记录,西屯鱼的发现加深了对真盔甲鱼类形态学及真盔甲鱼目乃至盔甲鱼亚纲中感觉管系统演化的认知。

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.

中国志留纪兰多维列世特列奇早期下红层对比之古鱼类化石证据

Sat, 01 Jul 2023 16:24:05 GMT

题名: 中国志留纪兰多维列世特列奇早期下红层对比之古鱼类化石证据作者: 山显任; 赵文金; 林翔鸿; 陈阳; 李强; 朱敏; 盖志琨摘要:

Combined with two new fish-bearing beds from the Qingshui Formation in Wuning, Jiangxi and the Tangchiawu Formation in Ningguo, Anhui, processes on palaeoichthyological morphology and taxonomy, and revisions on the horizons of early Silurian fish fossils in China, the following processes are made: (1) the strata yielding Shuyuidae and Xiushuiaspidae in northwestern Zhejiang should be referred as the lower red beds Tangchiawu Formation, rather than the upper red beds Maoshan Formation; (2) the strata yielding Dayongaspidae in southeastern Anhui belong to the lower red beds Tangchiawu Formation; (3) the Houchiatang Formation belongs to the lower red beds according to the Dayongaspidae, Hanyangaspidae and Gumuaspidae yielded in this formation; (4) the Rongxi, Qingshui, Tangchiawu, and Houchiatang formations in South China and the Tataertag Formation in Tarim Basin can correlate with each other based on the palaeoichthyological evidence. On the basis of above progresses, the Wentang vertebrate assemblage yielded in the lower red beds of Hunan is revised, which is characterized by the occurrence and diversification of basal galeaspids (Dayongaspidae, Hanyangaspidae, and Xiushuiaspidae), the most basal Eugaleaspiformes (Shuyuidae), the most basal Polybranchiaspiformes (Gumuaspidae), and the Sinacanthidae of chondrichthyans.

摘要:

本文依据近年来在江西武宁清水组及安徽宁国唐家坞组中新发现的含鱼层位, 结合古鱼类形态学与系统学研究结果, 对中国含志留纪早期鱼化石的主要层位进行梳理, 认为: (1) 浙西北地区产曙鱼科和修水鱼科化石的地层为唐家坞组, 属于下红层, 而非上红层茅山组; (2) 皖东南地区产大庸鱼科化石的地层为唐家坞组, 属于下红层; (3) 依据所产的大庸鱼科、汉阳鱼科、古木鱼科等原始盔甲鱼类化石, 苏皖地区侯家塘组属于下红层;(4) 根据古鱼类化石, 华南的溶溪组、清水组、唐家坞组、侯家塘组与新疆塔里木盆地的塔塔埃尔塔格组可以直接对比, 时代为志留纪兰多维列世特列奇早期。基于古鱼类化石新认识, 本文修订了产于湖南下红层中的温塘鱼类化石组合, 该组合主要以盔甲鱼亚纲中的基干盔甲鱼类(汉阳鱼科、修水鱼科、大庸鱼科)、最原始的真盔甲鱼类(曙鱼科)、最原始的多鳃鱼类(古木鱼科)与软骨鱼类中的中华棘鱼类的出现与繁盛为特征。

湖北武汉地区志留系下红层的古鱼类化石及其生物古地理意义

Sat, 01 Jul 2023 15:57:42 GMT

题名: 湖北武汉地区志留系下红层的古鱼类化石及其生物古地理意义作者: 山显任; 朱敏; 赵文金; 盖志琨摘要: Based on the new findings of fossil fishes from the Silurian shallow marine red beds at the Gumushan section, Wuhan, Hubei Province, the lower Telychian Llandovery) red beds are confirmed to be developed in southeastern Hubei. The original Fentou Formation in Wuhan area is emended and subdivided into two parts: the upper part is the emended Fentou Formation, while the lower part is calledQingshui Formation. The redefined Fentou Formation is characterized by yellowish-green, gray-green, and gray-yellow mudstones, argillaceous siltstones, and siltstones bearing abundant brachiopods, bivalves, gastropods, trilobites, and trace fossils. The lower part of the Qingshui Formation consists of purple-red, reddish-brown mudstones and argillaceous siltstones intercalated with quartz sandstones, while its upper part is dominated by purple-red and yellowish-green quartz sandstones intercalated with mudstones, argillaceous siltstones and siltstones containing lots of fossil fishes. Fishes from the upper part of the Qingshui Formation include the galeaspids Hanyangaspis guodingshanensis, Hongshanaspis inexpectatus, Jiangxialepis retrospina, and the chondrichthyans Sinacanthus and Neosinacanthus, all belonging to the Wentang Fish Assemblage of the Zhangjiajie Vertebrate Fauna. The galeaspid J. retrospina can be compared directly to J. jiujiangensis from the Qingshui Formation in Wuning area, Jiangxi Province, as members of the ge-nus Jiangxialepis assignable to the family Shuyuidae, whose members are elements of the Silurian Lower Red Beds in South China. According to comprehensive analysis of the fish assemblage and stratigraphic sequence, the Lower Red Beds in Wuhan, with an age of early Telychian, can be correlated with the Houjiatang Formation in Anhui and Jiangsu, the Tangchiawu Formation in Zhejiang, the Qingshui Formation in Jiangxi, the Rongxi Formation in Hunan, and the Tataertag Formation in Tarim Region. In addition, the distribution pattern of the Silurian Lower Red Beds in the South China Block indicates that the Upper and Lower Yangtze seas were connected by a narrow shallow epeiric water during the early Telychian, which probably provides a precondition for the galeaspids dispersing and communicating between Wuning of Jiangxi and Wuhan of Hubei. 摘要: 依据在湖北武汉古姆山志留系浅海红层中新发现的古鱼类化石，确证了兰多维列统特列奇阶下部红层——志留系下红层在鄂东南地区广泛存在，并在前人工作基础上对武汉地区原坟头组进行了重新厘定，将其一分为二，上部仍为坟头组，下部则称清水组。新厘定后的坟头组以黄绿色、灰绿色、灰黄色泥岩、泥质粉砂岩、粉砂岩为主，富含腕足类、双壳类、腹足类、三叶虫和遗迹化石；清水组下部以紫红色、红褐色泥岩、泥质粉砂岩为主，夹少量石英砂岩，上部以紫红色、黄绿色石英砂岩为主，夹泥岩、泥质粉砂岩、粉砂岩。在清水组上部新发现的鱼类化石包括盔甲鱼类锅顶山汉阳鱼(Hanyangaspis guodingshanensis)、意外洪山鱼(Hongshanaspis inexpectatus)、后棘江夏鱼(Jiangxialepis retrospina)及软骨鱼类中华棘鱼(Sinacanthus)、新中华棘鱼(Neosinacanthus)。这些新发现的古鱼均为张家界脊椎动物群温塘鱼类化石组合中的成员，其中，后棘江夏鱼可以跟产自江西武宁地区下红层清水组中的九江江夏鱼(J.jiujiangensis)直接对比，二者同属于真盔甲鱼目曙鱼科江夏鱼属，而曙鱼科成员则可以作为志留系下红层的标志性分子。根据鱼群面貌和地层层序，武汉地区的志留系下红层可以与皖、苏地区的侯家塘组、浙西北地区的唐家坞组、赣西北地区的清水组、湘西北地区的溶溪组以及新疆塔里木地区的塔塔埃尔塔格组进行很好的对比，其时代为志留纪兰多维列世特列奇期早期。华南板块志留系下红层的分布特征表明，在特列奇期早期，上、下扬子海之间存在一狭长的浅海区域，这为盔甲鱼类在湖北武汉和江西武宁两地之间的扩散与交流提供了便利条件和可能。

The first galeaspid fish (stem-gnathostomata) from the Silurian Xiushan formation of Hunan Province, China

Sat, 01 Jul 2023 15:45:22 GMT

题名: The first galeaspid fish (stem-gnathostomata) from the Silurian Xiushan formation of Hunan Province, China 作者: Zhang, Yumeng; Li, Xutong; Shan, Xianren; Lin, Xianghong; Tan, Kai; Li, Qiang; Zhao, Wenjin; Tang, Lizhou; Zhu, Min; Gai, Zhikun 摘要: A new species of Dayongaspidae, Dayongaspis colubra sp. nov., is described from the Telychian (Llandovery, Silurian) Xiushan Formation at Maoyanhe Town, Zhangjiajie, Hunan Province, China. The new species is distinguished from the type species D. hunanensis by its larger-sized headshield, tiny and dense granular tubercles, and triangular-shaped inner cornual processes. Additionally, it reveals more galeaspid plesiomorphic characters than D. hunanensis, such as the inverted splayed posterior supraorbital canals (soc(2)) and the paired endolymphatic openings on the headshields. This new finding represents the first fossil record of galeaspids in the Xiushan Formation, thereby enriching the diversity of galeaspids. Furthermore, it extends the Wentang Vertebrate Assemblage upwards into the lower part of Xiushan Formation, indicating a broader stratigraphic range than previously assumed.

Postcranial disparity of galeaspids and the evolution of swimming speeds in stem-gnathostomes

Sat, 01 Jul 2023 15:26:11 GMT

题名: Postcranial disparity of galeaspids and the evolution of swimming speeds in stem-gnathostomes 作者: Gai, Zhikun; Lin, Xianghong; Shan, Xianren; Ferron, Humberto; Donoghue, Philip C.J. 摘要:

Galeaspids are extinct jawless relatives of living jawed vertebrates whose contribution to understanding the evolutionary assembly of the gnathostome bodyplan has been limited by absence of postcranial remains. Here, we describe Foxaspis novemura gen. et sp. nov., based on complete articulated remains from a newly discovered Konservat-Lagerstätte in the Early Devonian (Pragian, ∼410 Ma) of Guangxi, South China. F. novemura had a broad, circular dorso-ventrally compressed headshield, slender trunk and strongly asymmetrical hypochordal tail fin comprised of nine ray-like scale-covered digitations. This tail morphology contrasts with the symmetrical hypochordal tail fin of Tujiaaspis vividus, evidencing disparity in galeaspid postcranial anatomy. Analysis of swimming speed reveals galeaspids as moderately fast swimmers, capable of achieving greater cruising swimming speeds than their more derived jawless and jawed relatives. Our analyses reject the hypothesis of a driven trend towards increasingly active food acquisition which has been invoked to characterize early vertebrate evolution.

First Middle Devonian galeaspid from the Haikou Formation in Yunnan Province

Sat, 01 Jul 2023 15:12:45 GMT

题名: First Middle Devonian galeaspid from the Haikou Formation in Yunnan Province 作者: Meng, Xin-Yuan; Zhu, Min; Wang, Jun-Qing; Pan, Zhao-Hui; Gai, Zhi-Kun 摘要: 早埃姆斯期生物事件是中国泥盆纪脊椎动物演化过程中最重要的生物事件，对盔甲鱼类的生物多样性产生了重大影响。在埃姆斯期之后，具有浓厚区域性色彩的盔甲鱼类几乎灭绝，只有少数属种遗存，如发现于华南广西中泥盆统艾菲尔阶的近中显眶鱼(Clarorbis apponomedianus)以及西北宁夏上泥盆统弗拉阶的一个多鳃鱼类未定种。首次报道了产自云南省武定县海口组的第一个中泥盆世盔甲鱼——东方鱼未定种(Dongfangaspis sp.)。与宽甲鱼(Laxaspis)和多鳃鱼(Polybranchiaspis)相比，这件新标本呈现出明显的东方鱼属的特征：近圆形的头甲，内角小，腹环宽且近乎等宽，约有45对鳃囊。东方鱼具有有史以来数目最多的鳃囊，这可能帮助它们在早、中埃姆斯期生物事件中幸存下来。这一新发现也是第二个中泥盆世盔甲鱼类化石记录，并将东方鱼属的生存时代从早泥盆世布拉格期扩展到了中泥盆世艾菲尔期。摘要: The Early Emsian Event (E’Em Event), the most signifcant bio-event for Chinese Devonian vertebrates, has significantly impacted on the diversity of galeaspids. The endemic Galeaspida almost became extinct after the Mid-Emsian Event (M’Em Event). Only few galeaspid taxa survived from these events, such as Clarorbis apponomedianus from the Eifelian of Guangxi, South China, and an indeterminate galeaspid from the Frasnian of Ningxia, Northwest China. Here, we report the first Middle Devonian galeaspid, Dongfangaspis sp., from the Haikou Formation in Wuding, Yunnan Province. The new material is more suggestive of the type species of Dongfangaspis, D. major, than Laxaspis and Polybranchiaspis in its suborbicular headshield with small inner cornual process, broad and nearly aequilate ventral rim, and about 45 pairs of branchial fossae. Dongfangaspis bears the largest number of branchial fossae ever recorded in galeaspids, which probably play an important role in Dongfangaspis surviving from the E’Em and M’Em events. The new fnding represents the second Middle Devonian fossil record of galeaspids, and extends the chronological range of Dongfangaspis from the Pragian (Early Devonian) to the Eifelian (Middle Devonian).

Falxcornus, a new genus of Tridensaspidae (Galeaspida, stem-Gnathostomata) from the Lower Devonian in Qujing, Yunnan, China

Sat, 01 Jul 2023 14:59:32 GMT

题名: Falxcornus, a new genus of Tridensaspidae (Galeaspida, stem-Gnathostomata) from the Lower Devonian in Qujing, Yunnan, China 作者: Meng, Xinyuan; Gai, Zhikun 摘要: A new genus and species of galeaspid, Falxcornus liui gen. et sp. nov., is described from the Xishancun Formation (Lochkovian, Lower Devonian) in Qujing, Yunnan, China. The new taxon displays a suite of diagnostic characters of the Eugaleaspiformes and strikingly resembles the tridensaspids Tridensaspis and Pterogonaspis in its sickle-like complex of cornual and inner cornual processes, leaf-like inner cornual processes, and median dorsal opening posteriorly placed level with the centre of the orbital opening, but clearly differs from these genera in lacking the rostral process and laterally projecting cornual processes. An extended phylogenetic analysis of the Galeaspida suggests that Falxcornus, Pterogonaspis and Tridensaspis form a monophyletic group as the family Tridensaspidae, and Falxcornus is resolved as sister to Pterogonaspis and Tridensaspis. Therefore, Falxcornus liui gen. et sp. nov. now represents the most primitive and oldest known tridensaspid fsh. Its subacute rostral margin and sickle-like complex of cornual and inner cornual processes likely represent an intermediate state of these highly specialised rostral and lateral projecting processes, respectively. The recurrent evolution of similar cephalic elaborations within the Galeaspida suggests that some galeaspids could manipulate water ﬂow around their headshields to become active animals with higher manoeuvrability and versatility, similar to osteostracans.

A New Species of Jiangxialepis (Galeaspida) from the Lower Telychian (Silurian) of Jiangxi and its Biostratigraphic Significance

Sat, 01 Jul 2023 14:02:20 GMT

题名: A New Species of Jiangxialepis (Galeaspida) from the Lower Telychian (Silurian) of Jiangxi and its Biostratigraphic Significance 作者: Shan, Xianren; Zhao, Wenjin; Gai, Zhikun 摘要: A new species of Shuyuidae (Eugaleaspiformes, Galeaspida), Jiangxialepis jiujiangensis sp. nov., is described from the lower Telychian (Llandovery, Silurian) Qingshui Formation in Jiujiang, Jiangxi Province, China. The new species differs from the type species J. retrospina from Wuhan, Hubei Province in its sharp and posteriorly positioned median dorsal spine and narrow spine-shaped inner cornual processes. The Silurian strata in Xiushui-Wuning area has provided a standard framework for the correlation of Silurian shallow marine red beds in South China. Thus, the finding of J. jiujiangensis from the Silurian Lower Red Beds (LRBs) in Jiangxi Province bears very important biostratigraphic significance. It can directly compare to Jiangxialepis retrospina from the Fentou Formation in Wuhan, Hubei Province in the genus level. This indicates that the age of the fish-bearing strata in Wuhan is most likely to be the early Telychian rather than middle Telychian as previously assumed.