Discovery of diverse Pectocaris species at the Cambrian series 2 Hongjingshao formation Xiazhuang section (Kunming, SW China) and its ecological, taphonomic, and biostratigraphic implications

• Published in: PeerJ (San Francisco, CA) CA), 2024-04, Vol.12, p.e17230-e17230, Article e17230
• Main Authors: Jin, Changfei, Chen, Hong, Mai, Huijuan, Hou, Xianguang, Yang, Xianfeng, Zhai, Dayou
• Format: Article
• Language: English
• Subjects: Analysis; Arthropod; Environmental aspects; Evolutionary Studies; Hongjingshao formation; Hou Xian-Guang; Niche (Ecology); Niche differentiation; Paleontology; Pectocaris paraspatiosa; Xiazhuang assemblage; Zoology
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.17230

species are intermediate- to large-sized Cambrian bivalved arthropods. Previous studies have documented exclusively from the Cambrian Series 2 Stage 3 Chengjiang biota in Yu'anshan Formation, Chiungchussu Stage in SW China. In this study, we report sp. nov., and three other previously known from the Xiazhuang section in Kunming, which belongs to the Hongjingshao Formation and is a later phase within Cambrian Stage 3 than the Yu'anshan Formation. The new species can be distinguished from its congeners by the sparsely arranged endopodal endites and the morphologies of the abdomen, telson, and telson processes. We interpret sp. nov. as a filter-feeder and a powerful swimmer adapted to shallow, agitated environments. Comparison among the species reinforces previous views that niche differentiation had been established among the congeneric species based on morphological differentiation. Our study shows the comprehensive occurrences of species outside the Chengjiang biota for the first time. With a review of the shared fossil taxa of Chengjiang and Xiaoshiba biotas, we identify a strong biological connection between the Yu'anshan and Hongjingshao Formations.