Panderodus

Panderodus Is an extinct genus of jawless fish belonging to the order Conodonta. This genus had a long temporal range, surviving from the middle Ordovician to late Devonian.^[1] In 2021, extremely rare body fossils of Panderodus from the Waukesha Biota were described, and it revealed that Panderodus had a more thick body compared to the more slender bodies of more advanced conodonts.^[2] It also revealed that this conodont was a macrophagous predator, meaning it went after large prey.^[2]

Panderodus Temporal range: Middle Ordovician–Late Devonian PreꞒ Ꞓ O S D C P T J K Pg N
A body fossil of Panderodus from the Waukesha biota
Life restoration of the species Panderodus unicostatus, based on the Waukesha specimen
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Conodonta
Order:	†Panderodontida
Family:	†Panderodontidae
Genus:	†Panderodus Ethington, 1959
Type species
†Panderodus denticulatus
Species
†Panderodus denticulatus †Panderodus greenlandensis †Panderodus rhamphoides †Panderodus serratus †Panderodus spasovi †Panderodus sulcatus †Panderodus unicostatus

Discovery

Panderodus was first described in 1959 on the basis of its tooth structures known as conodont elements.^[2] In 1985 a poorly preserved body fossil of the species Panderodus unicostatus was discovered in the Waukesha biota, a fossil site located in southeastern Wisconsin.^[2][3] At the time of its discovery this specimen was the one of only two known conodont body fossils, the other one being a body fossil possibly belonging to Clydagnathus which was found in 1983 from Carboniferous rocks of Scotland.^[4] More body fossils have since been found, like a large fossil of the species Promissum pulchrum found in the upper Ordovician soom shale in South Africa in the 1990s, but only 11 total are so far known.^[2][5][6][7] The Waukesha fossil was known to have belonged to Panderodus, but wasn't fully analyzed until 2021.^[2] This fossil revealed that at least P. unicostatus had a thicker body then most other conodonts, and had more primitive shark-like teeth. These features suggest P. unicostatus was a macrophagous hunter, something rare in vertebrates from the Ordovician-Silurian (due to the fact that many of them had no jaws).^[2][5]

Classification

Panderodus is a conodont of the family Panderodontidae, with Its closest relative being Besselodus. This conodont was relatively primitive; unlike later conodonts whose teeth formed into a complex sieve, the teeth of Panderodus were large and shark-like. The teeth probably had their own roles, like locking prey into place. Conodonts themselves are an unusual grouping, as for more than a hundred years we only knew of them by their teeth structures.^[8] Conodonts are classed in the grouping Agnatha alongside jawless fish like lampreys and hagfish.^[9]

Conodonts such as Panderodus were typically small to medium sized, elongate, marine vertebrates that look similar to eels today.^[10] These creatures have been classified under a large amount of animals, however now they are recognized as agnathan vertebrates.^[11][2]

The phylogenetic position of Panderodus relative to other conodonts with complete apparatus reconstructions:^[2]

Chordata	Gnathostomata Cyclostomata †Conodonta †Furnishina †Problematoconites †Euconodonta †Cordylodus †Besselodus †Panderodus †Paracordylodus †Promissum †Notiodella †Erismodus †Clydagnathus †Idiognathodus

Venom

Another study found that some species of Panderodus exhibited body parts that would mean they would be venomous. This makes these conodonts some of the earliest known venomous organisms in the fossil record.^[11]

References

1. "Panderodus ✝". Mindat.org.
2. Murdock, Duncan J. E.; Smith, M. Paul (2021). "Panderodus from the Waukesha Lagerstätte of Wisconsin, USA: a primitive macrophagous vertebrate predator". Papers in Palaeontology. 7 (4): 1977–1993. doi:10.1002/spp2.1389. S2CID 237769553.
3. Mikulic, D.G.; Briggs, D.E.G.; Kluessendorf, J. (1985). "A new exceptionally preserved biota from the Lower Silurian of Wisconsin, U.S.A." Philosophical Transactions of the Royal Society of London B. 311 (1148): 75–85. Bibcode:1985RSPTB.311...75M. doi:10.1098/rstb.1985.0140.
4. Briggs, D. E. G.; Clarkson, E. N. K.; Aldridge, R. J. (1983). "The conodont animal". Lethaia. 16 (1): 1–14. doi:10.1111/j.1502-3931.1983.tb01993.x.
5. Donoghue, P. C. J.; Forey, P. L.; Aldridge, R. J. (May 2000). "Conodont affinity and chordate phylogeny". Biological Reviews. 75 (2): 191–251. doi:10.1111/j.1469-185X.1999.tb00045.x. PMID 10881388. S2CID 22803015.
6. Aldridge, Richard J.; Murdock, Duncan J. E.; Gabbott, Sarah E.; Theron, Johannes N. (2013). "A 17-element conodont apparatus from the Soom Shale Lagerstätte (Upper Ordovician), South Africa". Palaeontology. 56 (2): 261. doi:10.1111/j.1475-4983.2012.01194.x.
7. Gabbott, S.E.; R. J. Aldridge; J. N. Theron (1995). "A giant conodont with preserved muscle tissue from the Upper Ordovician of South Africa". Nature. 374 (6525): 800–803. Bibcode:1995Natur.374..800G. doi:10.1038/374800a0. S2CID 4342260.
8. "Conodonts". Ucl.ac.uk. 2002.
9. "What are conodonts?". Australian.museum.
10. Sweet WC. 1988. The Conodonta : Morphology, Taxonomy, Paleoecology, and Evolutionary History of a Long-Extinct Animal Phylum. New York: Clarendon Press
11. Szaniawski, Hubert (2009). "The Earliest Known Venomous Animals Recognized Among Conodonts" (PDF). Acta Palaeontologica Polonica. 54 (4): 669–676. doi:10.4202/app.2009.0045. S2CID 54942826.