Skioldia aldna Chengjiang Arthropod

Skioldia aldna

Phylum Arthropoda, Helmetiidae / Skioldidae

Geologic Time: Early Cambrian (~525 million years ago)

Size: Fossil is 26 mm long

Fossil Site: Chengjiang Maotianshan Shales - Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Haiyi Village, Anning, Kunming County, Yunnan Province, China

Skioldia aldnaThis Helmetid arthropod is known as Skioldia aldna. The species is known from only a few examples as of 2004, some of which are as much as 100 mm in length. HelmetidaeSkioldiaThe taxon has some resemblance to the younger Burgess Shale arthropod Hemetia expansa that has led some to place them in the Helmetidae along with several other similar arthropods from Chengjiang and the Burgess Shale. Other scientists have suggested that the Helmetidae are the closest sister taxon to trilobites in the Cambrian fossil record. Skioldia has currently, however, been assigned its own family, Skioldidae. The body shape suggests that, like the similar taxon Kuamaia, it was a benthic animal that also was possibly carnivorous. Unlike Kuamaia, Skioldia has considerably less distinct segmentation. The central digestive system is the most distinct feature seen on this exceptionally rare specimen. The species is only known from the Chengjiang Biota.


Also see: Chengjiang Biota Relatives and Ancestors of Trilobites Chengjiang Fossils Cambrian Explosion

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