First occurrence of the Cambrian arthropodSidneyiaWalcott, 1911 outside of Laurentia

Abstract

The arthropod Sidneyia Walcott, 1911 is a remarkable animal of the Burgess Shale biota (Cambrian Miaolingian, Wuliuan; British Columbia, Canada), which has not been confidently reported from other Cambrian Konservat-Lagerstätten. Here we report the discovery of Sidneyia cf. inexpectans from the Wuliuan Mantou Formation of North China, which substantially expands the known palaeogeographical distribution of this genus. Our discovery suggests that Sidneyia had much greater dispersal ability than hitherto thought. It also confirms the presence of exceptionally preserved fossils in the Wuliuan Mantou Formation, one of the rare Burgess Shale-type deposits of North China.

Occurrence of the hurdiid radiodontCambrorasterin the middle Cambrian (Wuliuan) Mantou Formation of North China

“…Hurdiidae indet. was found in Bed B along with bivalved euarthropods Tuzoia , sponges, chancelloriids, and worm-like animals (Sun et al, 2020). On the basis of biostratigraphic correlation (e.g., Fletcher and Collins, 1998, 2003; Geyer, 2019; Zhu et al, 2019), the Upper Shale Member of the Mantou Formation is one trilobite zone younger than the Burgess Shale (Fig.…”

“…The fossils described here were collected from the Upper Shale Member of the Mantou Formation ( Bailiella lantenoisi Zone, corresponding to the Ptychagnostus gibbus Zone, uppermost Wuliuan) in the Longgang section, Linqu County, Shandong Province, North China (Fig. 1.1) (Sun et al, 2020). The Mantou (alternative spelling ‘Manto’) Formation is widely distributed in North China and is subdivided into the Shidian Member, the Lower Shale Member, the Honghe Member, and the Upper Shale Member in Shandong Province (Zhang and Liu, 1996).…”

“…The discovery of exceptionally preserved fossils in the Upper Shale Member, Mantou Formation in recent years (e.g., Sun et al, 2015, 2020; Wang et al, 2018) has drawn attention to the middle Cambrian Konservat-Lagerstätten in North China and their relations to the Burgess Shale (Sun et al, 2020). The discovery of the wonderful Burgess Shale–type hurdiid radiodonts will further add to the evidence for such phenomenon.…”

Paleomagnetic insights into the Cambrian biogeographic conundrum: Did the North China craton link Laurentia and East Gondwana?

“…Recently, some exceptionally preserved fossils were reported from the middle Cambrian strata in the NCC, and a few of the fossil species have not been confidently reported outside Laurentia thus far (Sun et al, 2020a(Sun et al, , 2020b. For example, the arthropods Sidneyia and Cambroraster, remarkable animals from the Burgess Shale biota (Wuliuan; British Columbia, Canada), have been discovered recently from the Wuliuan shales in the eastern NCC (Sun et al, 2020a(Sun et al, , 2020b. The Burgess Shale-type fossil biotas have been found from most continents in the Cambrian, but common fossil components among these biotas are usually pelagic and nektonic organisms.…”

“…Interesting questions are when and how the trilobites in different realms began to communicate with each other. The North China craton (NCC) has long been considered to have a close biogeographic association with East Gondwana because it yields the typical redlichiid trilobites (e.g., Zhang, 2003), but recent discoveries of a few characteristic fossils of Laurentia in Wuliuan shales in the eastern NCC (Sun et al, 2020a(Sun et al, , 2020b, together with the mixture of middle and late Cambrian trilobites among the NCC, East Gondwana, and Laurentia (e.g., Zhang, 2003;Álvaro et al, 2013;Collette, 2014;Wernette et al, 2020), prompt us to investigate the role of the NCC in biogeographic changes between East Gondwana and Laurentia in the middle to late Cambrian.…”