Microfossil of Protomelission from Wirrealpa. Reproduced from Zhang et al. 2021[2]
Scientific classification
(unranked):
Viridiplantae
Division:
Chlorophyta
Class:
Ulvophyceae
Order:
Dasycladales (?)
Genus:
†Protomelission Brock, G. A. & Cooper, B. J. 1993[1]
Protomelission is a Cambrian fossil taxon of contested affinity. It comprises cataphract arrays of box-like chambers, forming a club-shaped thallus surrounding a hollow central cavity. It was first described from phosphatized microfossils whose individual chambers were interpreted as housing the zooids of a non-mineralized bryozoan, which would make it the only affinity representative of that phylum – implying that all animal phyla originated in the Cambrian period.[3]
The subsequent discovery of articulated macrofossils from the Xiaoshiba[4] biota called into question the biological nature of the distal apertures, showing that the surface was instead covered with leaf-like triangular flanges. This has led to the reinterpretation of the fossil material as a "seaweed", strictly as a dasycladalean green alga.[5]
^Brock, Glenn A.; Cooper, Barry J. (1993). "Shelly fossils from the Early Cambrian (Toyonian) Wirrealpa, Aroona Creek, and Ramsay Limestones of South Australia". Journal of Paleontology. 67 (5): 758–787. doi:10.1017/S0022336000037045. S2CID 132278189.
^Zhang, Zhiliang; Zhang, Zhifei; Ma, Junye; Taylor, Paul D.; Strotz, Luke C.; Jacquet, Sarah M.; Skovsted, Christian B.; Chen, Feiyang; Han, Jian; Brock, Glenn A. (2021). "Fossil evidence unveils an early Cambrian origin for Bryozoa". Nature. 599 (7884): 251–255. Bibcode:2021Natur.599..251Z. doi:10.1038/s41586-021-04033-w. PMC 8580826. PMID 34707285.
^Ernst, Andrej; Wilson, Mark A. (2021). "Bryozoan fossils found at last in deposits from the Cambrian period". Nature. 599 (7884): 203–204. Bibcode:2021Natur.599..203E. doi:10.1038/d41586-021-02874-z. PMID 34707263. S2CID 240073927.
^https://www.mindat.org/paleo_loc.php?id=23464
^Yang, Jie; Lan, Tian; Zhang, Xi-Guang; Smith, Martin R. (2023). "Protomelission is an early dasyclad alga and not a Cambrian bryozoan". Nature. 615 (7952): 468–471. doi:10.1038/s41586-023-05775-5. PMID 36890226. S2CID 257425218.
Protomelission is a Cambrian fossil taxon of contested affinity. It comprises cataphract arrays of box-like chambers, forming a club-shaped thallus surrounding...
from fossilized and modern forms. In 2021, some research suggested Protomelission, a genus known from the Cambrian period, could be an example of an early...
compared to spicules of ecdysozoan worms, whereas others likely belong to Protomelission-like organisms, which have been argued to be affiliated with the dasycladalean...
Allonnia. Yang et al. (2023) reinterpret putative Cambrian bryozoan Protomelission as an early dasycladalean green alga, and conclude that there are no...
relationships of Heterocorallia, is published by Berkowski et al. (2021). Protomelission gatehousei is reinterpreted as a potential stem-group bryozoan by Zhang...
Jie; Lan, Tian; Zhang, Xi-Guang; Smith, Martin R. (8 March 2023). "Protomelission is an early dasyclad alga and not a Cambrian bryozoan". Nature. 615...
(2023) reinterpret Protomelission as an early dasycladalean green alga; however, Xiang et al. (2023) subsequently interpret Protomelission as a scleritome...