Panderodus, an Early Silurian conodont from Wisconsin USA

Sorry, still no relief from the WPlink issue in WordPress
so if you want to see Panderodus in situ, click this link: http://www.reptileevolution.com/birkenia.htm and scroll down past this taxon’s relatives in the LRT.

Note: I just learned to add html links to a MSWord doc and copy the lot over. Unfortunately images do not yet copy over.

https://www.myoutube.co/watch?v=GxwEblmPsW0

A recent 12-12-25 YouTube video on conodonts
by Ben G Thomas entitled, “What on Earth were the conodonts” [linked above] explained the history of conodont research and focused on a 2021 paper by Murdock and Smith redescribing Panderodus, preserved with soft tissue – all without revealing the closest relatives of conodonts.

Whenever a video is titled with a question mark, the odds drop that the video creator will answer the question posed.

My comments to the video follow.

After phylogenetic analysis hagfish-like Promissum nests with more fish-like Euphanerops + Drepanolepis and these were basal to more fish-like Birkenia, then Lasanius, then even more fish-like Cheirolepis, then extant Engraulis. This is a separate origin of jaws and teeth from many fish, but this lineage ultimately produced tetrapods and video watchers. So we humans have conodonts in our ancestry, while sturgeons, sharks and catfish do not.

Conodont ancestors include Nuucichthys + Metaspriggina and then older Pikaia and extant Myxine (the hagfish) and extant Enoplus, a marine nematode with radial elements surrounding an oral cavity. That’s as far back as this cladogram goes http://reptileevolution.com/reptile-tree.htm

Lampreys were basal to sturgeons, sharks, placoderms and their descendants.

re: Panderodus – The authors wrote, “However, the presence of the dorsoventral collapse of the apparatus may indicate that the specimen was also dorsoventrally flattened in life and came to rest on a stable body surface.The transverse myomeres would be consistent with this anatomy, in contrast to the acute W-shaped myomeres that would be expected from the dorsoventral collapse of an animal with a laterally compressed body as seen, for example, in Metaspriggina.”

That’s an interesting hypothesis, but the authors also reported, “Eyes are a feature of both the Granton and Soom material but are absent here.”

That is incorrect. Large, typical conodont eyes are visible in the matrix, on either side of a short pointed snout, the preoral lobe in lancelets. By homology conodont teeth are hardened versions of the buccl cirri that extend beyond the oral cavity in lancelets and have a homology in nautilus tentacles and sea cucumber circumoral projections = ambulacra. If Panderodus was dorsoventrally flat, it would be unique among its relatives, which range from tube-like to laterally-flattened.

Donoghue, Forey and Aldridge 2000 employed 17 chordate taxa and 103 characters to determine that, “conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata.”

The authors did not realize there is no monophyletic clade Gnathostomata because jaws and teeth developed convergently several times within the Chordata according to the LRT which tests 2340 taxa.

Panderodus unicostatus
(Branson and Mehl, 1933, Smith et al 1987, Murdock and Smith 2021) was an Early Silurian conodont known from the anterior half. The lancelet-like atrium is present. The eyes and preoral lobe were traced using DGS methods. See: http://www.reptileevolution.com/birkenia.htm

References
Branson EB and Mehl MG 1933. Conodonts from the Bainbridge (Silurian) of Missouri. University of Missouri Studies, 8, 39–52.
Briggs DEG, Clarkson ENK and Aldridge RJ 1983. The conodont animal. Lethaia. 16 (1): 1–14.
Donoghue and Forey PL and Aldridge RJ May 2000. Conodont affinity and chordate phylogeny. Biological Reviews. 75 (2): 191–251.
Murdock DJE and Smith MP 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
Smith MP, Briggs DEG and Aldridge RJ 1987. A conodont animal from the Lower Silurian of Wisconsin, U.S.A., and the apparatus architecture of panderodontid conodonts. 91–104. In ALDRIDGE, R. J. (ed.) Palaeobiology of conodonts. Ellis Horwood, 180 pp.

wiki/Panderodus

Source: https://pterosaurheresies.wordpress.com/2025/12/13/panderodus-an-early-silurian-conodont-from-wisconsin-usa/