Tanglangia longicaudata

Phylum Arthropoda

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

Fossil Site: Chengjiang Maotianshan Shale, Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Mafang Village, Haikou County, Kunming, Yunnan Province, China

Description: This unusual arthropod is known as Tanglangia longicaudata. With the discovery of the Chengjiang Biota by Hou Xian-guang in 1984, the world became aware of a great storehouse of material from early in 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 specimen is a member of the “great appendage arthropods” known as the opabinids after Opabinia from the Burgess Shale Fauna. It is most closely allied with Jianfengia, the most primitive of the opabinids. It differs primarily in having fewer segments and a long telson. The largest complete examples can reach 35 mm, with the telson in some cases being as long as the abdomen. The taxon is unknown outside the Chengjiang Biota. This one is incomplete, showing only the posterior half of this unusual arthropod; a complete specimen would have 13 body segments. This is the first such example I have been able to secure.