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...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。展开更多
The early Silurian Chongqing Lagerstätte(middle Telychian)yields exceptionally preserved articulated jawless and jawed fishes.Here,we describe a new eugaleaspiform(Galeaspida,jawless stem-Gnathostomata),Miaojiaas...The early Silurian Chongqing Lagerstätte(middle Telychian)yields exceptionally preserved articulated jawless and jawed fishes.Here,we describe a new eugaleaspiform(Galeaspida,jawless stem-Gnathostomata),Miaojiaaspis dichotomus gen.et sp.nov.,from the Chongqing Lagerstätte in Xiushan,Chongqing,China.The new form resembles Tujiaaspis vividus in the short medial dorsal canal,and the presence of the branching ends of the lateral transverse canal.They differ in that T.vividus has highly developed subordinate branches of the sensory canals that form a reticulate sensory canal system,and the median dorsal opening is more elongated.Our phylogenetic analysis recovers M.dichotomus and T.vividus as a monophyletic clade(Tujiaaspidae fam.nov.),which is supported by two synapomorphies:the short medial dorsal canal,and the branching ends of the lateral transverse canal.Tujiaaspidae forms a trichotomy with Shuyuidae and a clade comprising Anjiaspis,Sinogaleaspidae,Yongdongaspidae,and the‘eugaleaspid cluster’.The sensory canal patterns in galeaspids are compared to show the transformation sequence of the sensory canal system in Eugaleaspiformes.展开更多
文摘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。
文摘The early Silurian Chongqing Lagerstätte(middle Telychian)yields exceptionally preserved articulated jawless and jawed fishes.Here,we describe a new eugaleaspiform(Galeaspida,jawless stem-Gnathostomata),Miaojiaaspis dichotomus gen.et sp.nov.,from the Chongqing Lagerstätte in Xiushan,Chongqing,China.The new form resembles Tujiaaspis vividus in the short medial dorsal canal,and the presence of the branching ends of the lateral transverse canal.They differ in that T.vividus has highly developed subordinate branches of the sensory canals that form a reticulate sensory canal system,and the median dorsal opening is more elongated.Our phylogenetic analysis recovers M.dichotomus and T.vividus as a monophyletic clade(Tujiaaspidae fam.nov.),which is supported by two synapomorphies:the short medial dorsal canal,and the branching ends of the lateral transverse canal.Tujiaaspidae forms a trichotomy with Shuyuidae and a clade comprising Anjiaspis,Sinogaleaspidae,Yongdongaspidae,and the‘eugaleaspid cluster’.The sensory canal patterns in galeaspids are compared to show the transformation sequence of the sensory canal system in Eugaleaspiformes.
