| Selkirkia | |
|---|---|
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| Selkirkia columbia fossil from theBurgess Shale. FromSmith et al. (2015)[2] | |
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| Restoration ofSelkirkia columbia | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Stem group: | Priapulida (?) |
| Class: | †Archaeopriapulida |
| Family: | †Selkirkiidae Conway Morris, 1977[1] |
| Genus: | †Selkirkia Walcott, 1911 |
| Species | |
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Selkirkia is a genus of predatory,[3] tubicolouspriapulid worms known from the MiddleCambrianBurgess Shale, Ogygopsis Shale,Puncoviscana Formation[4] and the EarlyOrdovicianFezouata Formation.[5] 142 specimens ofSelkirkia are known from the GreaterPhyllopod bed, where they comprise 0.27% of the community.[6] In the Burgess Shale, 20% of the tapering, organic-walled tubes are preserved with the worm inside them, whereas the other 80% are empty (or sometimes occupied by one or more smallagnostid trilobites).[3] Whilst alive, the tubes were probably vertical, whereas trilobite-occupied tubes are horizontal.[3]
Selkirkia had a body divisible into a proboscis towards the anterior of a trunk enclosed by a tube. The proboscis would have been partially invertable and was armed with several spinules and spines, decreasing size distally overall. It was controlled by at least two sets of anterior retractor muscles. Immediately behind the proboscis was the trunk, smooth for the most part but lined with papillae towards the anterior. Surrounding the trunk was the tube, which way very finely annulated (4 annulations per 0.1 millimeters).
Members ofCambrorhytium were originally described asSelkirkia before their identification as a separate genus.[7]
