Anomalocaris saron Grasping Appendage
"Largest Member Chengjiang Biota & Terror Of The Cambrian"

Anomalocaris saron

Phylum Uncertain, Anomalocarididae

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

Size: 60 mm

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

Anomalocaris saronDiscovered in 1984, the Chengjiang Biota now ranks as the most diverse faunal fossil assemblage of all the Burgess Shale like deposits. It is also some 10 million years older than the Burgess Shale. Like the Burgess Shale, non-mineralized soft tissue parts are often extraordinarily well preserved with high resolution as aluminosilicate films, sometimes with oxidized iron content. Various taphonomic processes leading extensive preservation of soft tissue have been proposed, including rapid death by asphyxia followed by rapid burial in anoxic sediment undisturbed by turbidity. The Chengjiang biota is dominated by phyla Arthropoda and Porifera. There are seven lobopodians, more than any other Lagerstätte that some scientists elevate to phylum rank, and seven members of the extinct phylum Vetulicolia. Members or potential members of phyla Priapulida, Nematomorpha, Hyolitha, Hemichordata, Echinodermata, Ctenophora, Chordata, Cnidaria, Chaetognatha, and Brachiopoda are found. A large number of enigmatic animals of uncertain affinity are found as well, some of which may represent failed evolutionary experiments, or even new phyla that did not persist for long in the early Cambrian, or were rapidly replaced by more derived forms. Among the diverse Maotianshan Shales fauna, of utmost important are the putative early chordates, particularly Haikouella, potentially an ancestor to or the earliest craniate chordate. Myllokunmingia and Haikouichthys are interpreted as early Craniata, and possibly very primitive agnathids, the progenitor of the fishes and all vertebrates.

AnomalocarisThis is the grasping appendage of the so called “Terror of the Cambrian”, Anomalocaris saron. The enigmatic Anomalocaris is known from Asia, Australia, Europe, and North America, and is thought by many to be closely related to Arthropods. The spiniferous grasping appendages are strongly supporting of a carnivorous lifestyle. Trilobite fossils from Utah often show evidence of bite marks that have been made by Anaomalocaris. Anomalocaris saron is only known from the Chengjiang biota, but is likely closely related to Anomalocaris canadensis, the type species, from the younger Burgess Shale and Utah. The genus derives its name from “anomalous shrimp”, which was what the describer thought the appendage was.

Also see: Chengjiang Biota, Chengjiang Fossils, Cambrian Explosion

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