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| Yujingia glutenotunica He, Mussini, Han, Reich, Ou, Cheng & Shu, 2026 |
Highlights:
• A new early Cambrian ambulacrarian, Yujingia, preserves soft parts and tentacles
• Yujingia possesses pinnate appendages with filter-feeding grooves
• Phylogenetic analyses place Yujingia near the common ancestor of extant Ambulacraria
• The fossils suggest living ambulacrarians evolved from tentaculate suspension feeders
Summary
The origins of ambulacrarians, which comprise the morphologically disparate echinoderms (sea stars and their relatives) and the worm-like hemichordates, are poorly constrained, obscuring the assembly of their exceptionally disparate body plans. We describe Yujingia glutenotunica, an ambulacrarian from the early Cambrian Chengjiang biota (518 Ma). Yujingia combines a simple cylindrical body plan with a crown of specialized appendages, including pinnate arms bearing filter-feeding grooves and alternating side-branches. Phylogenetic analyses recover Yujingia within a grade of tentaculate fossils immediately basal to the last common ancestor of all modern ambulacrarians. These results suggest that ambulacrarians evolved from semi-sessile organisms with complex suspension-feeding adaptations, otherwise only found in crown-group echinoderms and tentaculate hemichordates (pterobranchs). Yujingia fills a key gap in the early deuterostome fossil record, thus challenging the conventional worm-like, pharyngeal filter-feeder models for the ambulacrarian last common ancestor and supporting unexpectedly deep origins for the echinoderm and pterobranch body plans.
Keywords: Ambulacraria, Chengjiang biota, deuterostome evolution
Systematic paleontology
Superphylum Ambulacraria
Phylum, Class, Order, Family indet.
Yujingia glutenotunica gen. et sp. nov.
Etymology: The generic name Yujingia refers to the Dharma Vessel held by Guanyin, one of the Four Great Bodhisattvas of Chinese Buddhism, in reference to the fossil’s overall shape. The specific name glutenotunica is derived from the Latin words gluten and tunica, which refers to the optically light body preserved around the visceral mass of the fossil. ...
Kaiyue He, Giovanni Mussini, Jian Han, Mike Reich, Qiang Ou, Meirong Cheng and Degan Shu. 2026. Cambrian Fossils illuminate the ambulacrarian common ancestor. Current Biology. DOI: doi.org/10.1016/j.cub.2026.08.053 [September 16, 2026]
