Reconstruction of the scleritome of Dailyatia bacata
The camenellans, consisting of the genera Camenalla, Dailyatia, Kennardia, Kelanella, Wufengella and Lapworthella, are a (probably monophyletic) group of Tommotiid invertebrates from the Cambrian period, reconstructed as sister to all others[clarification needed] (plus brachiopods and phoronids). They are primarily known from isolated sclerites, but are believed to have a scleritomous, Halkieria-like construction.[2][3] This was confirmed by the discovery of Wufengella, known from articulated remains, which showed camenellans to be mobile, worm-like animals.[4]
Dailyatia and Camenella have distinct dorsal (symmetrical) and lateral (asymmetric) sclerite morphologies.
The same has been asserted for Lapworthella[5] even though that has not always been the common perception.[3]
It has been argued that Camenella, Kelanella and Lapworthella, assuming a slug-like anatomy, had an anterior 'head valve' followed by pairs of asymmetric valves running in pairs along their dorsal surface.[5]
The 'head valve' in Lapworthella - that is the bilaterally symmetric Morph A valve - is thought to have fused from two ontogenetically separate sclerites.[5]Dailyatia has a similar double-mounded structure at the tip of its A type sclerites.[2]
Growth rings in all are marked out by prominent external ridges.[2][5]
^Devaere, L. et al. The tommotiid Kelanella and associated fauna from the early Cambrian of southern Montagne Noire (France): implications for camenellan phylogeny. Palaeontology 57, 979–1002 (2014).
^ abcSkovsted, C. B., Betts, M. J., Topper, T. P. & Brock, G. A. The early Cambrian tommotiid genus Dailyatia from South Australia. Mem. Assoc. Australas. Palaeontol. 48, 1–117 (2015).
^ abMurdock, D. J. E., Donoghue, P. C. J., Bengtson, S. & Marone, F. Ontogeny and micro-structure of the enigmatic Cambrian tommotiid Sunnaginia Missarzhevsky, 1969. Palaeontology 55, 661–676 (2012).
^Guo, Jin; Parry, Luke A.; Vinther, Jakob; Edgecombe, Gregory D.; Wei, Fan; Zhao, Jun; Zhao, Yang; Béthoux, Olivier; Lei, Xiangtong; Chen, Ailin; Hou, Xianguang; Chen, Taimin; Cong, Peiyun (2022). "A Cambrian tommotiid preserving soft tissues reveals the metameric ancestry of lophophorates". Current Biology. Online: S0960–9822(22)01455–5. doi:10.1016/j.cub.2022.09.011. ISSN 1879-0445. PMID 36170853.
^ abcdDevaere, L. & Skovsted, C. B. New early Cambrian sclerites of Lapworthella schodakensis from NE Greenland: advancements in knowledge of lapworthellid taxonomy, sclerite growth and scleritome organization. Geol. Mag. (2016). doi:10.1017/S0016756816000698
The camenellans, consisting of the genera Camenalla, Dailyatia, Kennardia, Kelanella, Wufengella and Lapworthella, are a (probably monophyletic) group...
similar to modern lophophorates. However, the discovery of the articulated camenellan Wufengella showed that it was a free-living worm-like animal, suggesting...
Wufengella is a genus of extinct camenellan "tommotiid" that lived during the Early Cambrian (Stage 3). Described in 2022, the only species Wufengella...
and halkieria) are unrelated to Wiwaxia, but are instead related to the camenellan tommotiids and thus belong in the brachiopod stem lineage. Paleontology...
scalidophoran Markuelia, and early post-embryonic developmental stages of camenellans is described from the Cambrian Stage 3 Salanygol Formation (Mongolia)...