胴甲鱼目(Antiarchi)发表评论(0)编辑词条

    胴甲鱼目（Antiarchi）是一类已经灭绝的鱼类，属于盾皮鱼类，生活在志留纪早期至泥盆纪晚期，也是最早的有颌鱼类之一，身体前半部覆盖有坚硬的骨甲。

    胴甲类在中国发现得最多，在世界其他地区仅限于中、晚泥盆世，而中、晚泥盆纪的胴甲鱼,不仅肩带和胸鳍高度特化,更在胸鳍和肩带之间形成一个精巧、复杂的肩关节，因此，胴甲类的起源和演化，一向是古鱼类学者感兴趣和有分歧的问题之一。

    中国最先发现的盾皮类化石是湖南、云南中泥盆世的胴甲类沟鳞鱼，50年代在四川发现了节甲类的江油鱼。近20多年,在中国西南、西北各省区,发现了大量胴甲鱼化石，特别是在早泥盆世地层发现了世界其他地区未曾发现的原始胴甲鱼类──云南鱼类 (Yunnanolepiformes)和始突鱼类(Procondylolepiformes)，这些原始胴甲鱼的一般外形轮廓与中、晚泥盆世的胴甲鱼基本一致，但肩关节的结构十分简单，云南鱼仅有一个漏斗状的腋窝，完全没有一般胴甲鱼所特有的肢突，说明其处于胴甲类发展演化的最低级阶段；始突鱼的肩关节，刚刚出现肢突，发育很不完善，显示其处于从无肢突到全肢突的中间阶段。

    中国原始胴甲鱼的发现和研究，基本揭示出胴甲类发展演化的全过程，为了解胴甲鱼的起源和彼此间的系统关系提供了重要依据。80年代以来，在云南的志留纪地层和其他化石一起也发现了胴甲鱼化石，这是世界已知最低的层位，胴甲鱼类起源于东亚已获公认。

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