The presence in the Qingjiang biota of diverse kinorhynchs (mud dragons; see the fig¬ure) was highly unexpected. These molting invertebrates are less than 1 mm in length and live buried in modern-day marine sedi¬ments. Kinorhynchs have only been found once so far in the fossil record, as tiny three-dimensional phosphatic microfossils from the early Cambrian (12). The Qingjiang biota reveals at least three new kinorhynch-like taxa with lengths of up to 4 cm, which seem to have lived on the seafloor rather than buried within it. Could the evolution of this phylum be characterized by large early-diverging taxa that progressively reduced their body size as they buried deeper into the seafloor