福建永安下白垩统坂头组Elatides属雌球果化石研究

Female cones of Elatides from the Lower Cretaceous Bantou Formation of Yongan,Fujian Province

对采自福建永安市下白垩统坂头组的似纵属Elatides雌球果化石进行了宏观形态和角质层特征的研究,这些球果均单独保存,较小,果鳞较多,螺旋状紧密排列,顶端收缩呈尖刺状,与Elatides的特征相符。根据球果的形态、果鳞及其球果中轴的特征,将这些球果鉴定为3个种,即永安似纵(新种)Elatides yonganensis Dai et Sun,sp.nov.、弯叶似纵(相似种)Elatidescf.curvifolius及一未定种Elatides sp.。其中重点描述了新种E.yonganensis的形态特征,该球果以中轴呈波状,果鳞顶端较长、较尖,腹面具有锯齿状的膜质小舌,每一果鳞具有大概5枚种子而区别于以前报道的任一已知种。同时对中国的Elatides化石记录进行了收集整理,Elatides属的球果化石在福建永安坂头组的发现表明其分布区可达25°N,丰富了该属植物的化石记录并扩大了其分布范围。

Some female cones of Elatides were collected from the Lower Cretaceous Bantou Formation,Yongan City,Fujian Province.The present authors have studied the gross morphology and cuticular features of them.These cones are all detached from the vegetative shoots,quite small and compact,with many cone scales.They are helically arranged along the cone axis,and their apices are spiny.The characteristics described above are consistent with the genus Elatides.According to the morphological characters of the cones,and the features of the cone scales and axis,these cones are recognized as three species： one new species Elatides yonganensis Dai et Sun,sp.nov.,one published species Elatides cf.curvifolius and one indeterminate species Elatides sp.The morphology of new species E.yonganensis has been especially described and compared in detail with other Chinese and European species.Elatides Yonganensis is different from the previously published species by its characters of flexuous cone axis,much longer and spiky apex of bracts,membranous ligules with serrate distal margin and probably five seeds on every adaxial cone scales.Additionally,the fossil records of Elatides in China have been reviewed and discussed.The occurrence of the Elatides cones in the Bantou Formation of Yongan City,Fujian Province,has extended the distribution range of Elatides to 25°N,and added the fossil records.