Fossil priapulid Ottoia from the Kaili biota (Cambrian Series 3) of South China

Abstract

The fossil priapulid Ottoia recovered from the Kaili biota, Cambrian Series 3 and Stage 5 of South China, is the first reported occurrence of the genus outside the Cambrian of Laurentia. A total of 22 specimens are described as Ottoia guizhouensis sp. nov. The new species is distinguished from other Cambrian priapulids, including the type species of Ottoia, O. prolifica Walcott, 1911 from the Burgess Shale, by the introvert that lacks a swollen base and bears a smaller number of longitudinal rows of hooks, and a more elongated trunk with more closely spaced annulations. Anatomically, a probable gizzard, a pair of posterior retractor muscles and muscle fibres of the gut wall are also observed in O. guizhouensis. The presence of the paired retractor muscles can be considered an indication of bilateral symmetry. Gut contents in O. guizhouensis suggest that this animal had an occasional deposit-feeding habit. Specimens buried in life position suggest that Ottoia may have burrowed and wriggled in all directions within the sediment and did not merely make U-shaped burrows. The new occurrence of Ottoia from the Kaili biota sheds new light on the morphology, anatomy and palaeogeographical distribution of this well-known genus, as well as providing new information on the early evolution of priapulids.

Keywords:

• Ottoia
• Priapulida
• Kaili biota
• Burgess Shale-type
• Cambrian
• South China

Acknowledgements

We gratefully acknowledge Dr Dong-jing Fu (Northwest University, China) for the reconstruction. Professors Jian Han (Northwest University, China) and Di-ying Huang (Nanjing Institute of Geology and Palaeontology, China) are thanked for beneficial discussions and help with the literature. Special thanks go to Dr Hai-jing Sun (Guizhou University, China) for providing several references, and to Mr Luo-yang Li (Northwest University, China) for assistance in SEM analysis. Drs Thomas Harvey (University of Leicester, UK), Martin Smith and Nicholas Butterfield (University of Cambrige, UK) are thanked for generously supplying a new paper (Smith et al. 2015), which was greatly beneficial to our research. Thomas Harvey and Prof. Steve LoDuca (Eastern Michigan University, USA) are thanked for scientific and linguistic assistance. The manuscript has also benefited from the insightful reviews of two anonymous reviewers. This work was financially supported by the Major Basic Research Project of the Ministry of Science and Technology of China under grant 2013CB835002 and the National Natural Science Foundation of China under grants 41272036, 41330101 and 41172005.

Supplemental material

Supplemental material for this article can be accessed here at: http://dx.doi.org/10.1080/14772019.2015.1077900