摘要
记述了产于湘西泸溪特马豆克期锅塘组的刺尾虫类三叶虫Ｄｉｃｈｅｌｅｐｙｇｅｌａｔａ的个体发育过程。其最显著的变化有头鞍形状和比例的改变，头鞍沟、颈沟与背沟的分离．鞍前箍（ｐａｒａｆｒｏｎｔａｌｂａｎｄ）的出现与消失．胸部肋区和轴部比例宽度的改变，尾部的形状和比例的变更，尾边缘的出现和肋沟深度的增加，以及后侧刺的位置逐渐前移。组成成虫期个体的前８个体节（６个胸节和前２个尾节）极有可能在分节０期（ｍｅａｓｐｉｄＤｅｇｒｅｅ０）便已形成。从分节３期（ｍｅｒａｓｐｉｄＤｅｇｒｅｅ３）起在带后侧刺的体节与轴后区（ｐｏｓｔａｘｉａｌｆｉｅｌｄ）之间又发育出一个新的体节。过渡期尾部（ｔｒａｎｓｉｔｏｒｙｐｙｇｉｄｉｕｍ）在分节０期或分节１期发育出后侧刺．在分节４期又同时长出３对侧刺，其中最后一对侧刺与后侧刺一道形成成年期尾部的尾刺。
Here described in detail is ontogeny of the ceratopygid Dichelepyge lata from the Guotang Formation in Luxi, western Hunan. The most distinct changes during its growth are the shape and proportion of glabella, the isolation of the glabellar and occipital furrows from the axial furrow, the appearance and obliteration of the parafrontal band, the proportional width of adaxial portion of thorax, the shape and proportion of pygidium and pygidial axis. the appearance of the pygidial border, the depth of the pleural furrows, and the location of the posterolateral spines. The 8 segments comprising thorax, and the first two pygidial segments in holaspis are very probably formed at the meraspis Degree 0. One more pleural segment on pygidium is subsequently added between the segment with posterolateral spines and the postaxial field. Posterolateral spines are certainly present in Degree 1 and persist in later developing stages. Subsequently 3 pairs of short lateral spines appear in meraspis Degree 4 with the posterior pairs retained in holaspides.
出处
《古生物学报》
CAS
CSCD
北大核心
1994年第1期48-62,137-138,共15页
Acta Palaeontologica Sinica
基金
国家自然科学基金
关键词
个体发育
刺尾虫类
三叶虫纲
Ontogeny, ceratopygid, Dichelepyge lata, Tremadoc, Hunan
