Morphology and systematics of the anomalocaridid arthropodHurdiafrom the Middle Cambrian of British Columbia and Utah

Hurdiid radiodontans from the middle Cambrian (Series 3) of Utah

“…Notably, the soft-bodied biotas from the middle Cambrian (Series 3) of Utah have yielded a large number of specimens previously identified as radiodontans in general, and 4 usually Anomalocaris Whiteaves, 1892or Peytoia Walcott, 1911(Daley and Bergström, 2012 (e.g., Conway Morris and Robison, 1982;Briggs and Robison, 1984;Conway Morris and Robison, 1988;Robison, 1991;Briggs et al, 2008), but the systematic position of most of this material has not yet been re-evaluated in light of the new discoveries on Hurdia. By analysis of appendages and mouthparts originally described in Conway Morris and Robison (1988) Daley et al (2013a) were able to conclude that Hurdia was in fact present in the middle Cambrian (Series 3) of Utah alongside Peytoia, and described four new specimens from the Spence Shale. Herein, we reconsider the identifications of radiodontan specimens from Utah in detail and confirm that Hurdia is well represented there.…”

“…Our understanding of the morphology and systematics of Hurdia Walcott, 1912 has greatly expanded in recent years, and it is now recognized as a significant taxon within Radiodonta present in several of the well-known Cambrian soft-bodied biotas including: the Burgess Shale in Canada and the nearby Stanley Glacier, Marble Canyon, Tulip Beds and Mount Stephen sites (Daley et al, 2009;2013a); the Jince Formation in the Czech Republic (Chlupáč and Kordule, 2002, fig. 7); Wheeler Formation (Robison and Richards, 1981, pl.…”

“…4, fig. 1a,b) and the Spence Shale (Daley et al, 2013a) in Utah, USA; the Shuinjingtuo Formation in China (Cui and Hou, 1990); and the Fezouata Biota in Morocco (Van Roy and Briggs, 2011, figs. 1d-i, S4a-c;1l, S3c,d, S4f).…”

“…A large frontal carapace of three sclerotized elements (two lateral P-elements and one dorsal H-element) and stalked eyes complete the head region. The body is made up of seven to nine segments, with reduced swimming flaps and prominent setal structures (Daley et al, 2009;2013a). A morphometric analysis showed that there are two species of Hurdia, H.…”

“…victoria and H. triangulata, which are differentiated by comparing the length and width of the 6 carapace H-element (Daley et al, 2013a). Hurdia and Peytoia have recently been recovered within Hurdiidae (e.g.…”