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1. chinaXiv:201906.00053 [pdf]

New material of thelodonts from Lochkovian(Lower Devonian) of Qujing, Yunnan, China

CUI Xin-Dong(1,2,3); LI Qiang(4); QIAO Tuo(1,2); ZHU Min(1,2,3)
Subjects: Biology >> Zoology

We reconstructed a wealth of three-dimensional virtual models of vertebrate microremains from the Xitun Formation and lower part of the Xishancun Formation (Lochkovian,Lower Devonian) of Qujing, Yunnan by means of high-resolution computed tomography. One genus (Parathelodus) and seven species (P. trilobatus, P. asiaticus, P. cornuformis, P. scitulus, P. xitunensis sp. nov., P. wangi sp. nov. and P. liaokuoensis sp. nov.) of thelodonts are described. The new discovery extends the stratigraphic distribution of Parathelodus from the Xitun Formation and the upper part of the Xishancun Formation to the lower part of the Xishancun Formation, the horizon close to the Silurian-Devonian boundary. The three new species, P. xitunensis, P. wangi and P. liaokuoensis, enhance our knowledge of the thelodont diversity from the Early Devonian of China.

submitted time 2019-06-17 From cooperative journals:《古脊椎动物学报》 Hits7817Downloads780 Comment 0

2. chinaXiv:201812.00009 [pdf]

The posterior cranial portion of the earliest known Tetrapodomorph Tungsenia paradoxa and the early evolution of tetrapodomorph endocrania

LU Jing; YOUNG Gavin; HU Yu-Zhi; QIAO Tuo; ZHU Min
Subjects: Biology >> Other Disciplines of Biology

Abstract Here the posterior cranial portion of the tetrapodomorph Tungsenia from the Lower Devonian (Pragian, ~409 million years ago) of Yunnan, southwest China, is reported for the first time. The pattern of posterior skull roof and the morphology of the otoccipital region of the neurocranium are described in detail, providing precious insight into the combination of cranial characters of the earliest known tetrapodomorph to date. The posterior cranium of Tungseniadisplays a mosaic of features previously linked either to basal dipnomorphs such as Youngolepis(e.g., the well-developed subjugular ridge, the strong adotic process, and the poorly developed fossa bridgei) or to typical tetrapodomorphs (e.g., the lateral dorsal aortae commenced from the median dorsal aorta postcranially). The independent ventral arcual plate is also found in the advanced tetrapodomorph Eusthenopteron. The new endocranial material of Tungsenia further fills in the morphological gap between Tetrapodomorpha (tetrapod lineage) and Dipnomorpha (lungfish lineage) and unveils the sequence of character acquisition during the initial diversification of the tetrapod lineage. The new phylogenetic analysis strongly supports the basalmost position of Tungsenia amongst the tetrapod lineage.

submitted time 2018-12-04 From cooperative journals:《古脊椎动物学报》 Hits4520Downloads1316 Comment 0

3. chinaXiv:201711.01912 [pdf]

New findings of galeaspids (Agnatha) from the Lower Devonian of Qujing, Yunnan, China

LIU Yu-Hai GAI Zhi-Kun ZHU Min
Subjects: Biology >> Zoology

New findings of galeaspids (Agnatha) including Altigibbaspis huiqingae gen. et sp. nov., an indeterminate polybranchiaspid, Eugaleaspis changi, and Nanpanaspis microculus are described from the lower part of the Xishancun Formation (early Lochkovian, Early Devonian) near the northeast entrance of Liaokuo Park, Qujing City, Yunnan Province, China. The Polybranchiaspis-like new genus is characterized by a blade-like median dorsal ridge on the dorsal side of head-shield. The morphological disparity of the median dorsal ridge and spine in galeaspids suggests that these structures functioned more than providing a hydrodynamic stability. We assume that a high upright and compressed spine may render galeaspid fishes an apparently larger size as seen by a predator, and a blade-like median dorsal ridge may accomplish a defense against the claws of large sea scorpions. Nanpanaspis is peculiar in bearing two short laterally projecting processes on each side of the head-shield, and its phylogenetic relationship is discussed based on different interpretations on the homology of these processes. Considering the unique morphology of Nanpanaspis, and its early occurrence among the Huananaspiformes, we assign Nanpanaspis in the monogeneric family Nanpanaspidae to represent an early branch of the Huananaspiformes.

submitted time 2017-11-07 From cooperative journals:《古脊椎动物学报》 Hits1457Downloads641 Comment 0

4. chinaXiv:201708.00334 [pdf]

New findings of galeaspids (Agnatha) from the Lower Devonian of Qujing, Yunnan, China

LIU Yu-Hai; GAI Zhi-Kun; ZHU Min
Subjects: Geosciences >> Geology

New findings of galeaspids (Agnatha) including Altigibbaspis huiqingae gen. et sp. nov., an indeterminate polybranchiaspid, Eugaleaspis changi, and Nanpanaspis microculus are described from the lower part of the Xishancun Formation (early Lochkovian, Early Devonian) near the northeast entrance of Liaokuo Park, Qujing City, Yunnan Province, China. The Polybranchiaspis-like new genus is characterized by a blade-like median dorsal ridge on the dorsal side of head-shield. The morphological disparity of the median dorsal ridge and spine in galeaspids suggests that these structures functioned more than providing a hydrodynamic stability. We assume that a high upright and compressed spine may render galeaspid fishes an apparently larger size as seen by a predator, and a blade-like median dorsal ridge may accomplish a defense against the claws of large sea scorpions. Nanpanaspis is peculiar in bearing two short laterally projecting processes on each side of the head-shield, and its phylogenetic relationship is discussed based on different interpretations on the homology of these processes. Considering the unique morphology of Nanpanaspis, and its early occurrence among the Huananaspiformes, we assign Nanpanaspis in the monogeneric family Nanpanaspidae to represent an early branch of the Huananaspiformes. 本文描述了云南曲靖早泥盆世西山村组盔甲鱼类(无颌类)的新发现,包括一新属、新种——惠清驼背鱼(Altigibbaspis huiqingae gen. et sp. nov.), 一件属种未定的多鳃鱼科标本,以及张氏真盔甲鱼(Eugaleaspis changi)和小眼南盘鱼(Nanpanaspis microculus)的新材料。驼背鱼在很多方面跟多鳃鱼都非常相似,但头甲背面具一特征性的驼背状隆起,其上有一刀刃状的中背脊。中背脊和中背棘在盔甲鱼类里的形态分异度表明:它们除了能够提供游泳方向稳定性外,可能衍生出了一些附加的功能,例如直立高耸的中背棘能使盔甲鱼在捕食者眼里具有了恐吓性,刀刃状的中背脊可能也起到一些防御的作用。南盘鱼头甲侧缘具有两对非常奇特的侧向延伸的突起;通过对这两对侧突同源性的比较,讨论了南盘鱼的潜在系统分类位置。鉴于南盘鱼奇特的形态,以及它在华南鱼目中相对较早的出现时代,建议暂时把南盘鱼放到一个单属科南盘鱼科,代表了华南鱼目早期分出来的一个支系。

submitted time 2017-08-24 From cooperative journals:《古脊椎动物学报》 Hits2489Downloads1072 Comment 0

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