Taxonomy
Beautifully preserved example of Paraconularia quadrisulcata, a close relative of Paraconularia subtilis, collected from Carboniferous rocks in Glasgow, Scotland.
Paraconularia subtilis is the first ever conulariid specimen ever described. Conulariids are extinct marine organisms their fossils are found in rocks that are between about 500 and 200 million years old.
Shells
Paraconularia subtilis shells like all conulariids are
- four-sided in the shape of a tall pyramid.
- made of calcium phosphate, like bones of vertebrates.
- grow from the pointed apex
- adding new material is added to the edge of the open aperture
- strongly ribbed
- each rib formed by a new growth increment like a tree ring
Relatives
For a long time the place of Paraconularia subtilis and other conulariids in the tree of life was unknown.
It is now believed that Paraconularia subtilis and other conulariids were relatives of
- sea-anemones
- corals
- jellyfish
The closest relatives of conulariids are jellyfish. Conulariids representing the fixed, so-called polyp stage of extinct jellyfish.