Lobopodian and Nematomorph Worm Assemblage from Chengjiang
"Cardiodictyon in association with nematomorph"
"part and counterpart"

Name: Lobopodia, Cardiodictyon catenulum & Nematomorpha, Maotianshania cylindrica

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

Size (25.4mm=1 inch): Size: mm (25.4mm=1 inch) Cardiodictyon: 30 mm long Maotianshania: 35 mm on a 45 mm by 75 mm matrix and 21 mm long on a 50 mm by 50 mm matrix

Fossil Site: Chengjiang Maotianshan Shales, Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Jianshan, Anning, Yunnan Province, China

Cardiodictyon catenulumDescription: 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 which may have represented failed attempts at diversity that did not persist to the present day.

The Lobopodians are small marine and terrestrial animals termed colloquially “velvet Lobopodian and Nematomorphworms” 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 richest 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 abnormally large. A complete example Lobopodianpossesses 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. The head is clearly seen on the counterpart example. Notice too the fine complete and partial worms present. This is Maotianshania cylindrica, a member of the Nematomorpha. The species is known from numerous specimens, many of which have preserved details, with the taxon named after, Maotianshan (Mao Tian Hill), site of the discovery of the Chengjiang Biota by Hou Xian-guang in 1984. The intestine is often preserved as a dark film, indicative of its deposit-feeding lifestyle.

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