| Coeloscleritophora Temporal range: Cambrian-Ordovician | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | incertae sedis |
| Class: | † Coeloscleritophora |
| Groups included | |
The Coelosclerithophorans are a polyphyletic group of organisms bearing hollow sclerites made of aragonite, and with a supposedly distinctive microstructure. [1]
Their skeletons may be homologous to those of the molluscs, [2] and Halkieria looks very much like a polyplacophoran. The shells of this group and the molluscs appear to have originated in the same fashion. [2] However, there are several reasons to doubt this relationship, [3] many of which may not pass muster. [4]
There are two groups within the coeloscleritophorans: the Sachitids, to which Halkieria and Wiwaxia belong, and the Chancellorids. The Ediacaran fossil Ausia has been touted as an ancestral 'intermediate' between both of these groups. [5]
These are common constituents of Lower Cambrian small shelly fossil assemblages.
