Taphonomic features of Haplophrentis carinatus from the Cambrian Kaili Formation, Jianhe, Guizhou and its symbiotic?relationship with eocrinids
The Cambrian Kaili Formation in Jianhe, Guizhou province yielded abundant hyolitha fossils, among which Haplophrentis carinatus accounted for the largest proportion and was the most well-preserved. Previous researches on Haplophrentis carinatus were merely limited to taxonomy, lacking further discussion on the taphonomic features of Haplophrentis carinatus and its symbiotic relationship with other organisms. Herein, we conducted a systematic research on 324 specimens of Haplophrentis carinatus. Four taphonomic modes of opercula were recognized: separately preserved opercula, internal or external molds of opercula, partially and completely?articulated opercula. Few helens were preserved and conchs were mainly preserved as internal molds. In addition, a trident-like structure occurring on internal molds or fossil impressions, which resembles soft-tissue preservation, was taphonomic artifacts. The symbiotic relationship between Haplophrentis carinatus and eocrinids was also discussed and treated as an amensalism.
National natural science foundation of China (49060010,49462010), national climbing special project (95-expert-01-1-6), science and technology foundation of guizhou province, national 973 project (2006CB806401)