本文报道了首次发现于内蒙古呼伦贝尔市莫力达瓦达斡尔族自治旗鸽子山化石点下白垩统龙江组的一件反鸟类。为确定该标本的解剖学特征和系统发育位置,本文对其进行了详细的骨骼特征描述,并与其他中生代鸟类进行了形态特征对比,进而通过TN...本文报道了首次发现于内蒙古呼伦贝尔市莫力达瓦达斡尔族自治旗鸽子山化石点下白垩统龙江组的一件反鸟类。为确定该标本的解剖学特征和系统发育位置,本文对其进行了详细的骨骼特征描述,并与其他中生代鸟类进行了形态特征对比,进而通过TNT软件对其进行了系统发育分析。形态特征对比研究结果表明该标本与渤海鸟科(Bohaiornithidae)特征最为相似,如叉骨上升支的末端膨大;尾综骨的末端逐渐收缩变细;胸骨的外侧突明显向胸骨后外侧偏转;第Ⅱ脚趾最为粗壮。然而,该标本又具有许多不同于其他已知渤海鸟类(bohaiornithids)的特征组合,如乌喙骨侧缘从中部开始强烈扩展;胸骨具有三角形的中间突和外边缘凹陷,胸骨前缘比较尖锐;小翼指爪节长而弯曲,大手指爪节短小粗壮。因此,我们建立渤海鸟科新属、新种——兴安北国鸟(Beiguornis khinganensis gen. et sp. nov.)。系统发育分析结果表明北国鸟与渤海鸟科的齿槽鸟(Sulcavis)和周鸟(Zhouornis)亲缘关系最近,三者构成一个单系类群(Zhouornis+‘Beiguornis+Sulcavis’)。除了长爪鸟(Longusunguis),渤海鸟科的其他类群与北国鸟均在一个单系类群内,确定了北国鸟在渤海鸟科的系统发育位置。兴安北国鸟是大兴安岭地区发现的第一件反鸟类,进一步丰富了该地区热河生物群组合面貌,而且在提高渤海鸟科属种丰富度的同时,把该类群的地理分布范围从冀北-辽西地区扩展到内蒙古大兴安岭地区,更为不同地区热河生物群对比研究提供了科一级的鸟类化石证据。展开更多
[ Objective] The aim was to observe the ultrastructure of different callus structures in Heiya No. 14 by transmission electron microscopy. [Methods] Sample preparation and observation were both carried out by conventi...[ Objective] The aim was to observe the ultrastructure of different callus structures in Heiya No. 14 by transmission electron microscopy. [Methods] Sample preparation and observation were both carried out by conventional transmission electron microscopy. [ Results] It was showed by transmission electron microscopy that the initial callus cells had a large central vacuole, which squeezed its cytoplasm to be a thin layer around the brim of cell, Meanwhile the nuclear was also squeezed to distribute in the corner of cell, but its nucleolus could be still observed; Compared embryogenic callus with initial callus, its cell wall became thick, and many starch grains and chloroplasts including starch grains could be observed in the cytoplasm area of cell membrane; In non-embryoenic callus, no organelles except for the vacuole could be observed; In browning callus, there was almost no organelles in cells. [ Conclusion] There are significant differences in different types of flax callus at the cell ultrastructure level, which can be as an index for reflecting the differentiation ability of callus cell.展开更多
文摘本文报道了首次发现于内蒙古呼伦贝尔市莫力达瓦达斡尔族自治旗鸽子山化石点下白垩统龙江组的一件反鸟类。为确定该标本的解剖学特征和系统发育位置,本文对其进行了详细的骨骼特征描述,并与其他中生代鸟类进行了形态特征对比,进而通过TNT软件对其进行了系统发育分析。形态特征对比研究结果表明该标本与渤海鸟科(Bohaiornithidae)特征最为相似,如叉骨上升支的末端膨大;尾综骨的末端逐渐收缩变细;胸骨的外侧突明显向胸骨后外侧偏转;第Ⅱ脚趾最为粗壮。然而,该标本又具有许多不同于其他已知渤海鸟类(bohaiornithids)的特征组合,如乌喙骨侧缘从中部开始强烈扩展;胸骨具有三角形的中间突和外边缘凹陷,胸骨前缘比较尖锐;小翼指爪节长而弯曲,大手指爪节短小粗壮。因此,我们建立渤海鸟科新属、新种——兴安北国鸟(Beiguornis khinganensis gen. et sp. nov.)。系统发育分析结果表明北国鸟与渤海鸟科的齿槽鸟(Sulcavis)和周鸟(Zhouornis)亲缘关系最近,三者构成一个单系类群(Zhouornis+‘Beiguornis+Sulcavis’)。除了长爪鸟(Longusunguis),渤海鸟科的其他类群与北国鸟均在一个单系类群内,确定了北国鸟在渤海鸟科的系统发育位置。兴安北国鸟是大兴安岭地区发现的第一件反鸟类,进一步丰富了该地区热河生物群组合面貌,而且在提高渤海鸟科属种丰富度的同时,把该类群的地理分布范围从冀北-辽西地区扩展到内蒙古大兴安岭地区,更为不同地区热河生物群对比研究提供了科一级的鸟类化石证据。
基金Supported by Harbin Postdoctoral Foundation(LRB08-491)~~
文摘[ Objective] The aim was to observe the ultrastructure of different callus structures in Heiya No. 14 by transmission electron microscopy. [Methods] Sample preparation and observation were both carried out by conventional transmission electron microscopy. [ Results] It was showed by transmission electron microscopy that the initial callus cells had a large central vacuole, which squeezed its cytoplasm to be a thin layer around the brim of cell, Meanwhile the nuclear was also squeezed to distribute in the corner of cell, but its nucleolus could be still observed; Compared embryogenic callus with initial callus, its cell wall became thick, and many starch grains and chloroplasts including starch grains could be observed in the cytoplasm area of cell membrane; In non-embryoenic callus, no organelles except for the vacuole could be observed; In browning callus, there was almost no organelles in cells. [ Conclusion] There are significant differences in different types of flax callus at the cell ultrastructure level, which can be as an index for reflecting the differentiation ability of callus cell.
