An Early Cambrian Hemichordate Zooid

作者：Hou Xian guang; Aldridge Richard J; Siveter David J; Siveter Derek J; Williams Mark; Zalasiewicz Jan; Ma Xiao ya

来源：Current Biology, 2011, 21(7): 612-616.

DOI：10.1016/j.cub.2011.03.005

Hemichordates are known as fossils from at least the earliest mid-Cambrian Period (ca. 510 Ma) and are well represented in the fossil record by the graptolithinid pterobranchs ("graptolites"), which include the most abundantly preserved component of Paleozoic macroplankton [1]. However, records of the soft tissues of fossil hemichordates are exceedingly rare and lack clear anatomical details [2]. Galeaplumosus abilus gen. et sp. nov. from the lower Cambrian of China [3], an exceptionally preserved fossil with soft parts, represents by far the best-preserved, the earliest, and the largest hemichordate zooid from the fossil record; it provides new insight into the evolution of the group. The fossil is assigned to the pterobranch hemichordates on the basis of its morphological similarity to extant representatives. It has a zooidal tube (coenecium) with banding throughout comparable to that in the extant pterobranchs and a zooid with paired annulated arms bearing paired rows of annulated tentacles; it also displays a putative contractile stalk. G. abilus demonstrates stasis in pterobranch morphology, mode of coenecium construction, and probable feeding mechanism over 525 million years.

• 出版日期2011-4-12
• 单位云南大学