Xandarella, an Exceptionally Rare Chengjiang Arthropod
with Extensive Soft Tissue Preservation

Xandarella spectaculum

Phylum Arthropoda

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

Size: Fossil is 38 mm long and 22 mm across on a 105 mm by 95 mm matrix

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


Xandarella spectaculumDescription: This unusual arthropod is known as Xandarella spectaculum. The species is known from very few examples, some of which show many exquisite details. 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 areknown as well, some of which may have represented failed attempts at diversity that did not persist to the present day.

Xandarella spectaculum is quite trilobite-like in appearance, but differs in the lack of a calcified exoskeleton and different eye morphology. The taxon is unknown outside the Chengjiang Biota. This is a truly unusual specimen preserved in dorsal fashion, one that few will ever be able to hold in a collection, whether private or that of a museum. The preservation is superb, with The central gut is clearly visible in this fine example which is seen here in ventral mode. Note too the preserved eyes, features usually not found preserved in such spectacular fashion, rending this an example true to the name of the species.

Also see: Chengjiang Biota List Chengjiang Fossils

click to enlarge


l Paleontology & Fossils l Paleobiology and Geologic Timeline l
l Fossil Amber l Ammonite Fossils l Dinosaur and Reptile Fossils l Fossil Kits l
l Crinoids and Echinoderms l Fish Fossils l Fossil Dealers l Insect Fossils l Invertebrate Fossils l
l Plant Fossils l Stromatolites l Trace & Ichnofossils l Trilobite Fossils l Vertebrate Fossils l