First record of Lower Triassic Undichna spp. fish swimming traces from Emei, Sichuan Province, China

Abstract

We discuss traces from the ichnospecies Undichna unisulca recorded from the Triassic that are reported for the first time in this paper. These fossils are also some of the oldest vertebrate ichnites discovered in China to date. The fish swimming traces (Undichna unisulca) described originate from the Lower Triassic. These traces were found in the Jialingjiang Formation and are located at a gorge ~7.5 km from Emei, Sichuan Province, China. The ichnospecies Undichna unisulca consists of a regular sinusoidal wave. The wavelengths and amplitudes are quite constant between each specimen ranging between 28-32 mm and 9-12 mm, respectively. The fish swimming traces and distribution within the same bed are preserved as hypichnial ridges at the undersurface.

First report on swimming trace fossils of fish from the Upper Permian and Lower Triassic of the Dolomites (Italy)

“…Starting from the diagnoses and classification of Anderson (1970Anderson ( , 1976 and Fliri et al (1970), trails of fish origin (Undichna) have been identified in different areas in strata dating back to the Devonian (Morrissey et al, 2004;Wisshak et al, 2004). After some pioneering works (Higgs, 1988;Turek, 1989), comprehensive revisions and descriptions of new ichnospecies have been proposed (Buatois and Mángano, 1994;Gibert et al, 1999;Trewin, 2000;Gibert, 2001;Soler-Gijón and Moratalla, 2001;Morrissey et al, 2004;Minter and Braddy, 2006;Costeur and Ezquerra, 2009;Buatois et al, 2010;Bordy et al, 2011;Lu et al, 2012). To date, in the Southern Alps, records of Undichna have been reported only by Todesco and Avanzini (2008), who identified Undichna gosiutensis Gibert, 2001 in the "Voltago Conglomerate" (Anisian, Middle Triassic).…”

A diverse trackway-dominated marine ichnoassemblage from the Lower Triassic in the northern Paleotethys: Ichnology and implications for biotic recovery

“…Undichna traces are all preserved as hypichnial ridges from the same bed. Interestingly, Undichna has rarely been reported from the Lower Triassic successions worldwide, although the first record of this ichnogenus was found in the Spathian Jialingjiang Formation, Sichuan Province, Southwest China (Lu et al, 2012).…”

“…The wavelength of all waves is ~40 mm, and their amplitudes decrease outward from 20 mm to 12 mm. Both the wavelength and amplitude are constant (Lu et al, 2012). Liu et al, 2015) showing the position of the studied section (red square).…”