The only Cambrian fossil species that seems to be closely related to the entoprocts is Cotyledion, but there are several other enigmatic animals that have also been tentatively allied with the group as members of early stem lineages.Continue reading “Cambrian Explosion Month #28: Phylum …Entoprocta?”
Ectoprocts, common known as bryozoans or “moss animals”, are aquatic lophotrochozoans that usually live in colonies made up of many tiny cloned zooids. The exoskeletons they build for their colonies have a range of forms, including gelatinous blobs, chitinous branches, and calcified sheets and coral-like fronds.
They’re part of a sub-group of lophotrochozoans called lophophorates, closely related to brachiopods and horseshoe worms, and are characterized by having a ring or U-shaped “crown” of filter-feeding tentacles around their mouths.
Mineralized bryozoans have an extensive fossil record going back to the early Ordovician, about 481 million years ago, but they’re surprisingly absent from the Cambrian – with one possible exception.Continue reading “Cambrian Explosion Month #27: Phylum Ectoprocta & Phylum Entoprocta”