A specimen of Paralycoptera Chang & Chou 1977 (Teleostei: Osteoglossoidei) from Hong Kong (China) with a potential Late Jurassic age that extends the temporal and geographical range of the genus

Tze-Kei Tse; Michael Pittman; Mee-Mann Chang

doi:10.7717/peerj.865

A specimen of Paralycoptera Chang & Chou 1977 (Teleostei: Osteoglossoidei) from Hong Kong (China) with a potential Late Jurassic age that extends the temporal and geographical range of the genus

PeerJ. 2015 Mar 26:3:e865. doi: 10.7717/peerj.865. eCollection 2015.

Authors

Tze-Kei Tse¹, Michael Pittman¹, Mee-Mann Chang²

Affiliations

¹ Vertebrate Palaeontology Laboratory, Life and Planetary Evolution Research Group, Department of Earth Sciences, The University of Hong Kong , Pokfulam, Hong Kong , China.
² Key Laboratory of Vertebrate Evolution and Human Origin of Chinese Academy of Sciences, Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences , Beijing , China.

Abstract

We describe a Mesozoic fish Paralycoptera sp. (Teleostei: Osteoglossoidei), on the basis of a postcranial skeleton collected from the volcaniclastic mudstones of the Lai Chi Chong Formation of Hong Kong, China. The new finding-representing the city's first Mesozoic fish-extends the geographical distribution of Paralycoptera from eastern mainland China into Hong Kong, demonstrating a wider distribution than previously appreciated for this genus. A radiometric age for the Lai Chi Chong Formation of 146.6 ± 0.2 Ma implies a temporal range expansion for Paralycoptera of approximately 40 million years back from the Early Cretaceous (∼110 Ma). However, spores found in the Formation suggest an Early Cretaceous age that is consistent with the existing age assignment to Paralycoptera. We argue that the proposed temporal range extension is genuine because it is based on recent high precision radiometric age data, but given the discrepancies with the biostratigraphic ages further investigation is needed to confirm this. This study provides an important step towards revealing Hong Kong's Mesozoic vertebrate fauna and understanding its relationship to well-studied mainland Chinese ones.

Keywords: Fish; Hong Kong; Jurassic; Lacustrine; Lai Chi Chong Formation; Osteoglossomorph; Paralycoptera; Volcanism.

Grants and funding

This study was supported by a Summer Research Fellowship awarded to Tze-Kei Tse by the Faculty of Science of the University of Hong Kong. The stereo microscope and photographic equipment used were purchased with equipment funds awarded to Michael Pittman by the Faculty of Science and the Department of Earth Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.