Extended Data Fig. 5: Saccorhytus coronarius.
From: Saccorhytus is an early ecdysozoan and not the earliest deuterostome

a, b, UMCU2014004, with only one large protuberance; a, anterior dorsal view (assuming an anterior mouth and dorsal large protuberances); b, abapertural or posterior view; c, d, UMCU2018014, with four large protuberances; c, right view; d, left view; e, f, same specimen as shown in Fig. 1a–e, UMCU2016009; e, close-up view of central right of Fig. 1d, with arrow indicating the two tightly adpressed integument layers and rectangle marking area enlarged in f, which illustrates randomly oriented nanometer-scale apatite crystals. Scale bar: 200 μm (a–d), 25 μm (e), 1 μm (f). See Fig. 1 for abbreviations.