Pywackia is a contentious
Cambrianfossil that has been interpreted as the earliest (
total group)
Bryozoan, and the only representative of that
phylum in the Cambrian period.[1]
Its Bryozoan credentials have been called into question,[2] but the
octocoral alternative is equally unconvincing, and there are reasons to suggest a position in the
Stenolaemata stem lineage.[3] Finally, the skeletal microstructure is consistent with a cnidarian affinity, but insufficient to support a close affinity with any modern subgroup.[4]
References
^Landing, E.; English, A.; Keppie, J. D. (2010). "Cambrian origin of all skeletalized metazoan phyla--Discovery of Earth's oldest bryozoans (Upper Cambrian, southern Mexico)". Geology. 38 (6): 547.
Bibcode:
2010Geo....38..547L.
doi:
10.1130/G30870.1.
^Ed Landing; Jonathan B. Antcliffe; Martin D. Brasier; Adam B. English (2015). "Distinguishing Earth's oldest known bryozoan (Pywackia, late Cambrian) from pennatulacean octocorals (Mesozoic—Recent)". Journal of Paleontology. 89 (2): 292–317.
Bibcode:
2015JPal...89..292L.
doi:
10.1017/jpa.2014.26.
S2CID131609198.