Lochkovian plants from the Xitun Formation of Yunnan, China, and their palaeophytogeographical significance

Xue, Jinzhuang

doi:10.1017/s001675681100077x

Cited by 21 publications

(16 citation statements)

References 57 publications

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“…The specimens come from a locality south of the Shangxishan Reservoir, near Qujing city, Yunnan, China (25°30.43′79″N 103°42.12′71″E; see Fig. 1 of Xue ), from the lower part of the Xishancun Formation, a thin bed of greenish grey mudstone in which axes of the marine dasycladalean alga Uncatoella verticillata have also been found. The specimens are in a fine sandy matrix with abundant plant remains; eurypterid fragments were also collected along with the specimens described here.…”

Section: Methodsmentioning

confidence: 99%

An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China

2015

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Two new specimens of the xiphosuran Kasibelinurus yueya Lamsdell, Xue & Selden, 2013 are described, from the same horizon and locality as the type. The new specimens are conspecific with the type, but show ventral morphology, which considerably alters interpretation of the species. It can no longer be referred to Kasibelinurus Pickett, 1993, and a new genus, Houia n. gen., is erected. Houia shows a unique combination of xiphosurid and chasmataspidid/eurypterid characteristics such as lack of opisthosomal pleura and possession of a large, ventral metastomal plate. Phylogenetic analysis of all the major chelicerate orders suggests that Houia branched from the main euchelicerate lineage prior to the divergence of the three constituent clades of the Dekatriata Lamsdell, 2013 (Eurypterida, Arachnida, Chasmataspidida). Together with bunodids and pseudoniscids, Houia provides evidence for basal dekatriatans persisting into the middle Palaeozoic alongside eurypterids and arachnids and that the morphological diversity of these basal forms was greater than previously thought.

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Section: Methodsmentioning

confidence: 99%

An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China

2015

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“…The Xishancun, Xitun, Guijiatun and Xujiachong formations (in ascending chronological order) represent the Early Devonian non-marine strata in Qujing District ( Liu & Wang, 1973 ; P’an et al, 1978 ; Zhu, Wang & Fan, 1994 ; Liu, Gai & Zhu, 2018 ). The Xitun Formation consists mainly of grayish-green muddy limestone and mudstone ( Fang et al, 1985 ; Xue, 2012 ), yielding a rich biota (Cuifengshan Assemblage) characterized by the diversification of sarcopterygians ( Chang & Yu, 1981 ; Chang & Yu, 1984 ; Zhu, Yu & Janvier, 1999 ; Zhu, Yu & Ahlberg, 2001 ; Zhu & Yu, 2002 ) and primitive antiarchs including Yunnanolepis, Parayunnanolepis , Zhanjilepis , Chuchinolepis and Phymolepis . Other fishes in the Xitun Formation include the endemic agnathans ( Liu et al, 2015 ), arthrodires ( Dupret, Zhu & Wang, 2017 ), actinopterygians ( Zhu et al, 2006 ; Lu et al, 2016 ), acanthodians and chondrichthyans, the latter two of which are mostly known from microvertebtrate remains ( Wang, 1984 ).…”

Section: Methodsmentioning

confidence: 99%

“…Other fishes in the Xitun Formation include the endemic agnathans ( Liu et al, 2015 ), arthrodires ( Dupret, Zhu & Wang, 2017 ), actinopterygians ( Zhu et al, 2006 ; Lu et al, 2016 ), acanthodians and chondrichthyans, the latter two of which are mostly known from microvertebtrate remains ( Wang, 1984 ). The Xitun Formation has been dated as late Lochkovian (c. 410–415 million years ago) with evidence from fossil assemblages ( Gao, 1981 ; Fang et al, 1994 ; Zhao et al, 2011 ; Xue, 2012 ).…”

Section: Methodsmentioning

confidence: 99%

Redescription ofPhymolepis cuifengshanensis(Antiarcha: Yunnanolepididae) using high-resolution computed tomography and new insights into anatomical details of the endocranium in antiarchs

Wang

Zhu

2018

PeerJ

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BackgroundYunnanolepidoids constitute either the most basal consecutive segments or the most primitive clade of antiarchs, a highly diversified jawed vertebrate group from the Silurian and Early Devonian periods. Although the general morphology of yunnanolepidoids is well established, their endocranial features remain largely unclear, thus hindering our further understanding of antiarch evolution, and early gnathostome evolution. Phymolepis cuifengshanensis, a yunnanolepidoid from the Early Devonian of southwestern China, is re-described in detail to reveal the information on endocranial anatomy and additional morphological data of head and trunk shields.MethodsWe scanned the material of P. cuifengshanensis using high-resolution computed tomography and generated virtual restorations to show the internal morphology of its dermal shield. The dorsal aspect of endocranium in P. cuifengshanensis was therefore inferred. The phylogenetic analysis of antiarchs was conducted based on a revised and expanded dataset that incorporates 10 new cranial characters.ResultsThe lateroventral fossa of trunk shield and Chang’s apparatus are three-dimensionally restored in P. cuifengshanensis. The canal that is positioned just anterior to the internal cavity of Chang’s apparatus probably corresponds to the rostrocaudal canal of euantiarchs. The endocranial morphology of P. cuifengshanensis corroborates a general pattern for yunnanolepidoids with additional characters distinguishing them from sinolepids and euantiarchs, such as a developed cranio-spinal process, an elongated endolymphatic duct, and a long occipital portion.DiscussionIn light of new data from Phymolepis and Yunnanolepis, we summarized the morphology on the visceral surface of head shield in antiarchs, and formulated an additional 10 characters for the phylogenetic analysis. These cranial characters exhibit a high degree of morphological disparity between major subgroups of antiarchs, and highlight the endocranial character evolution in antiarchs.

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Section: Methodsmentioning

confidence: 99%

Peer Review #2 of "Redescription of Phymolepis cuifengshanensis (Antiarcha: Yunnanolepididae) using high-resolution computed tomography and new insights into anatomical details of the endocranium in antiarchs (v0.1)"

Long¹

2018

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Background. Yunnanolepidoids constitute either the basal-most consecutive segments or the most primitive clade of antiarchs, a highly diversified jawed vertebrate group from the Silurian and Early Devonian periods. Although the general morphology of yunnanolepidoids is well established, their endocranial features remain largely unclear, thus hindering our further understanding of antiarch evolution, and early gnathostome evolution. Phymolepis cuifengshanensis, a yunnanolepidoid from the Early Devonian of southwestern China, is re-described in detail to reveal the information on endocranial anatomy and additional morphological data of head and trunk shields. Methods. We scanned the material of P. cuifengshanensis using high-resolution computed tomography a nd generated virtual restorations to show the internal morphology of its dermal shield. The dorsal aspect of endocranium in P. cuifengshanensis was therefore inferred. The phylogenetic analysis of antiarchs was conducted based on a revised and expanded dataset that incorporates ten new cranial characters. Results. The lateroventral fossa of trunk shield and Chang's apparatus arethree-dimensionally restored in P. cuifengshanensis. The canal that is positioned just anterior to the internal cavity of Chang's apparatus, probably corresponds to the rostrocaudal canal of euantiarchs. The endocranial morphology of P. cuifengshanensis corroborates a general pattern for yunnanolepidoids with additional characters distinguishing them from sinolepids and euantiarchs, such as a developed cranio-spinal process, an elongated endolymphatic duct, and a long occipital portion. Discussion. In light of new data from Phymolepis and Yunnanolepis, we summarized the morphology on the visceral surface of head shield in antiarchs, and formulated additional ten characters for the phylogenetic analysis. These cranial characters exhibit a high degree of morphological disparity between major subgroups of antiarchs, and highlight the endocranial character evolution in antiarchs.

show abstract

Lochkovian plants from the Xitun Formation of Yunnan, China, and their palaeophytogeographical significance

Cited by 21 publications

References 57 publications

An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China

An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China

Redescription ofPhymolepis cuifengshanensis(Antiarcha: Yunnanolepididae) using high-resolution computed tomography and new insights into anatomical details of the endocranium in antiarchs

Peer Review #2 of "Redescription of Phymolepis cuifengshanensis (Antiarcha: Yunnanolepididae) using high-resolution computed tomography and new insights into anatomical details of the endocranium in antiarchs (v0.1)"

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