Cranidial Shape Variation during Ontogeny in Ptychopariid Trilobite Jiulongshania acalla from the Cambrian Gushan Formation of Shandong Province and Its Ecological Implication

• Published in: Beijing da xue xue bao Vol. 60; no. 4; pp. 626 - 638
• Main Authors: Qin, Shujian, Dong, Lin
• Format: Journal Article
• Language: Chinese
• Published: Beijing Acta Scientiarum Naturalium Universitatis Pekinenis 01.01.2024
• Subjects: Cambrian; Feeding behavior; Ontogeny; Variation
• DOI: 10.13209/j.0479-8023.2024.040
• ISSN: 0479-8023

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.