Novel information on Caryosyntrips based on new appendages from China and the USA

Caryosyntrips is a relatively rare but long-lived and geographically widespread radiodont genus with specimens reported from Cambrian Stage 4 to the Drumian of Gondwana and Laurentia. Most of the currently known specimens are from the Wulian to Drumian deposits of North America and only one specimen is known from Stage 4 of Gondwana. Here, two new specimens are reported. The first one is a C. cf. Caryosyntrips serratus appendage from the Malong Biota of China (Cambrian, Series 2, Stage 3), which also represents the first reported occurrence of Caryosyntrips from China. The second appendage is from the Spence Shale Member (Cambrian, Miaolingian, Wuliuan) of Utah, USA and shares characters with both Caryosyntrips camurus and Caryosyntrips durus. This new specimen indicates that characters previously used to diagnose species might instead reflect intraspecific variation, however confirmation of this depends on discovery of new material. These new finds increase the temporal range of the genus into Cambrian Stage 3 and the specimen from the Malong Biota significantly increases the geographical range of the genus, with its first occurrence in China. In addition to the description of the new material we also discuss the function of the appendages in Caryosyntrips and the ecology of the genus.