山东寒武系崮山组褶颊虫类三叶虫Jiulongshania acalla个体发育过程中的头盖形态变化及其生态学意义OA北大核心CSTPCD

Based on a large number of cranidial specimens of Jiulongshania acalla Walcott,1905 from the Cambrian Gushan Formation at the Tangwangzhai section in Jinan City,Shandong Province,the traditional morphometric method and geometric morphometrics were used to measure and quantify the morphological features of the cranidium,revealing the cranidial shape variation during ontogeny.The results show that the growth rate of preglabellar field is the fastest,and the rate for the cranidial width is the slowest.The cranidial shape variation during ontogeny is mainly characterized by elongation of cranidium and gradual increase in the length of preglabellar field.It is proposed that the variation of trilobite exoskeletal morphology,particularly the cephalon,might be related to the feeding mode of trilobite.The results may suggest that the feeding habits of J.acalla might have changed during development.