贵州遵义松林寒武系牛蹄塘组Tsunyiella luna的个体发育初探

本文运用形态测量学方法对贵州遵义寒武系牛蹄塘组中高肌虫Tsunyiella luna的个体发育进行初步探讨。结果显示遵义地区T.luna的生长模式为异速生长,在壳高与壳长正交方向异速、非等比生长,高长比值随着壳体生长波动式降低,先增大再减小后增大;铰合线与壳长方向异速、等比生长,其比值随壳体生长成反比例降低;腹边缘均衡生长,蜕壳阶段不确定。个体发育阶段分为早、中和晚三个期,早期构造从无到有,高长比变大;中期前瘤和背缘脊在壳体占比逐渐减小,中背部逐渐增大,高长比逐渐减小;晚期前瘤在壳体占比略增大,背缘脊减小,中背部不明显,高长比变大。T.luna的个体发育探讨为该属种的准确鉴定和演化研究提供重要的信息。

THE PRELIMINARY STUDY ON THE ONTOGENY OF TSUNYIELLA LUNA FROM THE CAMBRIAN NIUTITANG FORMATION IN SONGLIN TOWN,ZUNYI COUNTY,GUIZHOU PROVINCE

The ontogeny of Tsunyiella luna of the Cambrian Niutitang Formation, Zunyi, Guizhou Province is studied preliminarily using the geometric morphometric method. The result shows that the growth pattern of T. luna is allometric. And the ratio between the hinge-line length and shell length is decreasing with inverse proportional function during the ontogeny. The ventral margin is balanced growth. However, the molting stage is still not clear now. The ontogeny can be divided into three stages: early stage, middle stage and late stage. In the early stage, structure is from scratch, and the ratio of the height to length became larger as the shell become round. In the middle stage, the proportion of anterior node and dorsal margin ridge in the shell and the ratio of height to length gradually decreased, and the mid-dorsal area gradually increased on the contrary and the shell form gradually retral swing. In the late stage, the proportion of anterior node in the shell increased slightly, and the dorsal margin ridge decreased, and the mid-dorsal area is not obvious, and the ratio of height to length increased, and the shell form was more round. This ontogenetic study provides more in formation for further study on taxonomy and phylogeny of T. luna.