Chancelloriida Walcott, 1920

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 384

Order Chancelloriida Walcott, 1920 Family Chancelloriidae Walcott, 1920 Genus Chancelloria Walcott, 1920

Type species: Chancelloria eros Walcott, 1920 ; middle Cambrian ; Burgess Shale, British Columbia, Canada .

Remarks.—The earliest undoubted articulated sclerites of Chancelloria sp. in Siberia are reported from the Purella Zone. These sclerites occur in the upper Ust’-Yudoma Formation (30 m below its top) in the Uchur-Maya region Khomentovsky et al. 1990: pl. 8: 5) and 22–23 m below the top of the Ust’-Yudoma Formation at “Dvortsy” (Val’kov 1983; Khomentovsky et al. 1990: pl. 10: 4?, 5, 6; Varlamov et al. 2008: 29). These occurrences are correlated herein with the upper part of the Fortunian Stage. The locally oldest

Chancelloria sp. sclerites are reported from the Ilsanella compressa – Anabarella plana Zone of western Mongolia (Voronin et al. 1982; Brasier et al. 1996) and Watsonella crosbyi Zone of Avalonia ( Bengtson and Fletcher 1983; Landing 1988; Landing and Murphy 1991).

Chancelloria symmetrica , reinterpreted as Chancelloriella irregularis by Moore et al. (2014), first appears in upper Assemblage Zone 2 of the Meishucunian Stage ( Annelitellus yangtzensis – Obtusoconus honorabilis Subzone , upper Fortunian Stage) in South China. Apart from the oldest chancelloriids with central rays from the upper Fortunian, a probable relative of the chancelloriids is Cambrothyra ampulliformis (= truncata) Qian and Zhang, 1983, with single-rayed sclerites, is known from the lower‒ middle Fortunian Assemblage Zone 1 of South China (Steiner et al. 2004a: fig. 2; Moore et al. 2010).