An early Cambrian craniate-like chordate

@article{Chen1999AnEC,
  title={An early Cambrian craniate-like chordate},
  author={Jun‐yuan Chen and Diying Huang and CHIA-WEI Li},
  journal={Nature},
  year={1999},
  volume={402},
  pages={518-522}
}
Since the identification of the Lower Cambrian Yunnanozoon as a chordate in 1995 (ref. 1), large numbers of complete specimens of soft-bodied chordates from the Lower Cambrian Maotianshan Shale in central Yunnan (southern China) have been recovered. Here we describe a recently discovered craniate-like chordate, Haikouella lanceolata, from 305 fossil specimens in Haikou near Kunming. This 530 million-year-old (Myr) fish-like animal resembles the contemporaneous Yunnanozoon from the Chengjiang… 
Pikaia gracilens Walcott, a stem‐group chordate from the Middle Cambrian of British Columbia
TLDR
The Middle Cambrian Pikaia gracilens (Walcott) has an iconic position as a Cambrian chordate, but until now no detailed description has been available and its relationships to both extant and extinct chordates and other deuterostomes are explored.
The first tunicate from the Early Cambrian of South China
TLDR
Based on new, more complete “Cheungkongella” specimens that show branching tentacles, this form may be a lophophorate, and in any case is not a tunicate.
The sudden appearance of diverse animal body plansduring the Cambrian explosion.
  • Jun‐yuan Chen
  • Biology
    The International journal of developmental biology
  • 2009
TLDR
These nested body plans portray a novel big picture of pararthropod evolution as a progression of step-wise changes both in the head and the appendages of Panarthropoda.
Fossil sister group of craniates: Predicted and found
TLDR
Haikouella agrees so closely with recent predictions about pre‐craniates that the difficult problem of craniate origins is nearly solved.
Cambrian Chordates and Vetulicolians
TLDR
The main objective of this review is to examine the Cambrian diversity of these two deuterostome groups, the chordates and the vetulicolians, which are of particular interest because of the link to vertebrates, andBecause of the enigmatic nature of vetULicolians.
Early crest animals and the insight they provide into the evolutionary origin of craniates
TLDR
Comparative study with the cephalochordate amphioxus suggests that precraniate evolution is marked by a series of innovations including: muscular ventilation with gill‐bearing and jointed brachial arches, paired head sensorial organs including paired eyes and nostrils, and some derivatives of neural crest cells.
Tentaculate Fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) Interpreted as Primitive Deuterostomes
TLDR
The evidence is suggested that the evidence is more consistent with the ambulacraria being primitive deuterostomes, with specific comparisons being made to the pterobranch hemichordates and pre-radial echinoderms.
Pikaia gracilens Walcott: stem chordate, or already specialized in the Cambrian?
  • J. Mallatt, N. Holland
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2013
TLDR
A cladistic analysis showed the character interpretations of CMC are consistent with their wide-ranging evolutionary scenario, but that these interpretations leave unresolved the position of Pikaia within chordates.
A paleontological perspective of vertebrate origin
TLDR
A five-step hypothesis for vertebrate origin is proposed, intended to bridge the longstanding gap between protostomes and vertebrates, and four of the five steps accord with established ideas current in modern evolutionary zoology.
...
...

References

SHOWING 1-10 OF 12 REFERENCES
Yunnanozoon and the ancestry of chordates
The oldest known chordate, Yunnanozoon lividum Hou et al. 1991, from the Chengiang Lagerstatte of Yunnan shows several features in its anatomy that had not been expected to occur at this stage of
A possible Early Cambrian chordate
TLDR
The first chordate recorded from the Early Cambrian is the ceph-alochordate Yunnanozoon lividum from the 525 million-year-old Chengjiang fauna and predicts that other chordate clades (tunicates and craniates) had evolved by the Late Atdabanian, in the main burst of the Cambrian Explosion.
Reinterpretation of Yunnanozoon as the earliest known hemichordate
TLDR
Yunnanozoon is reinterpreted here as the earliest known hemichordate, and its typical tripartite body plan is broadly consistent with that of living balanoglossid hemichor-dates (enteropneusts).
At the orgin of chordates
  • A. Blieck
  • Geography, Environmental Science
  • 1992
Landmarks in the Anterior Central Nervous System of Amphioxus Larvae
TLDR
Two issues are discussed: that the frontal eye of amphioxus is sufficiently similar in structure and organization to the paired eyes of vertebrates to indicate homology; and that its position at the extreme anterior end of the cord, together with structural and histochemical evidence, suggests it may derive from the apical organ.
Composition and preservation of the Chengjiang fauna –a Lower Cambrian soft‐bodied biota
The Lower Cambrian Chengjiang fauna is reviewed and shown to be closely comparable with the younger Burgess Shale fauna. but with various differences in detail. A diverse group of more or less
Details of the evolutionary history from invertebrates to vertebrates, as deduced from the sequences of 18S rDNA.
  • H. Wada, N. Satoh
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1994
TLDR
Phylogenetic comparisons of the sequences of 18S rDNA suggest the monophyly of the deuterostomes, with the exception of the chaetognaths, and support the hypothesis that chordates evolved from free-living ancestors.
The conodont controversies.
CONODONTS AND THE FIRST VERTEBRATES
The Life of Vertebrates
TLDR
The life of vertebrates is studied in detail in order to provide a fuller picture of the complex web of connective tissue in the animal kingdom.
...
...