Jamoytius
| Jamoytius | |
|---|---|
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Jamoytiiformes |
| Family: | †Jamoytiidae |
| Genus: | †Jamoytius |
| Species: | †J. kerwoodi
|
| Binomial name | |
| †Jamoytius kerwoodi White, 1946[1]
| |
Jamoytius kerwoodi is an extinct species of primitive,
Llandovery epoch of the Early Silurian
period.
Long thought of as a "basal anaspid," J. kerwoodi is now recognized as the best-known member of the
Hyperoartian order Jamoytiiformes. It had an elongated body, and is thought to have had, in comparison with relatives known from intact bodies like Euphanerops, a dorsal fin and an anal fin near the rearmost third of its body. Earlier reconstructions depict the creature as having side-fins running the length of its body, starting from behind the branchial openings to the tip of its tail: new research demonstrates that such "fins" are actually deformations of the bodywall as the corpse was being squished post-burial.[2] In life, J. kerwoodi resembled a lamprey with a very small mouth. Because the fossil had no teeth, teeth-like structures, nor suggestions of either in its mouth, it was not carnivorous like many modern lampreys
. It was more likely to have been a filter-feeder or a detritus-feeder, possibly in the manner of larval lampreys.
The fish had a cartilaginous skeleton, and a branchial basket resembling the
cyclostomes - features that suggest that it was a basal member of that clade. It is also the earliest known vertebrate with camera-type eyes.[3] It also possessed weakly mineralised scales.[4]
History of research
Jamoytius was originally named by Errol White on the basis of two specimens (the generic name is a reference to
synapomorphies. Currently, J. kerwoodi is now placed in its own order Jamoytiiformes, together with Euphanerops and similar agnathans.[2]
Further reading
- Long, John A. The Rise of Fishes: 500 Million Years of Evolution Baltimore: The Johns Hopkins University Press, 1996. ISBN 0-8018-5438-5
Links to images
References
- S2CID 86329654. Retrieved 2007-10-31.
- ^ .
- ^ Ritchie, A. (1968). "New evidence on Jamoytius kerwoodi White, an important ostracoderm from the Silurian of Lanarkshire, Scotland" (PDF). Palaeontology. 11: 21–39. Archived from the original (PDF) on 2011-07-16. Retrieved 2007-10-31.
- S2CID 129511577.
- ^ Dawkins, Richard The Ancestor's Tale
- S2CID 4214197.
