[关键词]
[摘要]
文中运用古植物学研究中的基本方法，对云南省曲靖市沾益县玉光村中泥盆统上部(Givetian阶)西冲组的压型化石进行了形态学研究。根据化石植物的形态学特征和具体的度量数据，确定了原始鳞木类石松植物Colpodexylon variabile 在西冲组中的发现，并由此对该植物的种征进行了修订。此前，Colpodexylon variabile 仅在沾益县史家坡剖面的西冲组被报道，其化石产地与本文的化石产地平面距离相距不足 1km。Colpodexylon variabile 茎轴较宽，茎轴表面叶基呈假轮状疏松排列，叶基纺锤形，长宽比1．2—1．8，叶末端分叉，具有三枚位于同一平面的裂片，其中的中央裂片最狭长，两枚侧裂片较小。孢子叶与营养叶同形，卵圆形的孢子囊着生在孢子叶的近轴面上。Colpodexylon属的各个种在全球中—晚泥盆世地层中广泛分布，形态特征变化较大，其可能并不是一个自然类群。
[Key word]
[Abstract]
New material of protolepidodendrid lycopsid Colpodexylon variabile， which was previously only reported from the Xichong Formation of Shijiapo，Qujing，are recognized from the Xichong Formation，late Middle Devonian (Givetian)in Yuguang，Qujing，Yunnan Province，Southwest China．The fossils are preserved as compression of gray-black siltstone．According to the morp-hological characteristics and the specific measu-rements the present fossil plant showed， an emended species diagnosis of C．variabile is given in respect of the detailed morphological information as below．Several species of Colpodexylon were widely distributed in the global Middle-Upper Devonian，their wide range of morphological characters probably suggest that the genus is not a natural group．
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[基金项目]
国家自然科学基金(41530103)资助
