A New Species of Yunnanozoan with Implications for Deuterostome Evolution

摘要: Yunnanozoans are a distinctive clade of Lower Cambrian metazoans. Although widely accepted as deuterostomes, their exact placement within this superphylum is controversial. Here we describe new species Haikouella (H. jianshanensis) from the Chengjiang Lagerstatte (Yunnan, China) with exceptional preservation number features. These include external gills, which suggest that origin pharyngeal clefts was independent gills. The diagnostic branchial arches chordates may, therefore, be composite structures. No evidence found for chordate-like structures have been described in other yunnanozoans. We propose yunnanozoans stem-group allied to vetulicolians.