Lobopodian Cardiodictyon catenulum from Chengjiang

"extant equivalent is velvet worm"

Cardiodictyon catenulum

Phylum Lobopodia

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

Size: 42 mm long

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

Cardiodictyon catenulumThe Lobopodians are small marine and terrestrial animals termed colloquially “velvet worms” or “worms with legs”. While all Recent forms are terrestrial, most fossil Lobopodians are marine, and are known primarily from the Cambrian. Six named genera, each with a single species, are known from the Chengjiang Biota, making it the Cardiodictyon catenulum from Chengjiangrichest source of fossils of the type on Earth. This is one of the most striking, and quite rare; as of 2004, well less than 100 examples were known. A large specimen was thought to be 20 mm, so this one is truly gigantic. It possesses 23 – 25 angular sclerotized paired sclerites, each pair of which is associated with a pair of legs. Each leg bears curved claws which are thought to have served the creature as an adaptation to crawling on other organisms. It is most closely related to Aysheaia from the younger Burgess Shale, and is unknown outside of Yunnan Province. This fine example has incredible detail, with the “myriapod”- like legs in clear evidence.

CardiodictyonDescription: The discovery of the Chengjiang Biota by Hou Xian-guang in 1984 resulted in a clear window on what is known as the Cambrian Explosion. The diversity of soft-tissue fossils is astonishing: algae, medusiforms, sponges, priapulids, annelid-like worms, echinoderms, arthropods (including trilobites), hemichordates, chordates, and the first agnathan fish make up just a small fraction of the total. Numerous problematic forms are known as well, some of that may have represented failed attempts at diversity whose descendents that did not persist to the present day.

Also see: Chengjiang Biota Fauna List Chengjiang Fossils

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