fossil is death assemblage with three specimens of primative
arthropod is known as Fuxianhuia protensa. The largest, most
complete one is atop the others, so the animals may not all have
been expired at the same time. Fuxianhuia is known from
hundreds of specimens, with this one coming from the
most famous location of all, Maotianshan (Mao Tian Hill), the
actual site of the
discovery of the Chengjiang Biota. The
taxon only occurs in Chengjiang.
classification is one of the most disputed fossils from the
site, with some considering it a euarthropod. The
Chengjiang Biota discoverer and coworker erected a
Proschizoramia which was characterized as a group at any early
stage in the evolution of arthropods with
biramous limbs (hou, et al., 1987). Another early analysis
described it as a stem group chelicerate (Will, et al., 1996).
More recently, Ma et al. (2012) suggested that the head, brain
and optic lobes had features simialar to a malacostracan (shrimp),
chilopod and insect, and therefore that Fuxianhuia might precede
by Hou Xian-guang in 1984, the Chengjiang
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.
Hou, X.-g (1987). "Three New Large Arthropods from Lower Cambrian,
Chengjiang, Eastern Yunnan [In Chinese]". Acta Palaeontolologica
Sinica 26: 272–285
Chen, JY; Edgecombe, G. D.; Ramsköld, L.; Zhou, L (1995). "Head
segmentation in Early Cambrian Fuxianhuia: implications for arthropod
evolution". Science 268 (5215): 1339–1343.
Wills, M. A.; Edgecombe, G. D.; Ramsk ld, L. (1996). "Classification
of the Arthropod". Science 272 (5262): 746–747.
Ma, X.; Hou,
X.; Edgecombe, G. D.; Strausfeld, N. J. (2012). "Complex brain
and optic lobes in an early Cambrian arthropod". Nature 490