Wuttagoonaspis: this ‘unusual’ Middle Devonian placoderm is a catfish

Short one today…

Considered “an unusual arthrodire” for almost five decades
Wuttagoonaspis (“what-a-goon-ass-piss”; Ritchie 1973, Middle Devonian; Fig. 1) nests in the large reptile tree (LRT, 1708+ taxa; Fig. x) with Clarias the extant walking catfish (Fig. 2).

The LRT nested catfish with placoderms
in May 2019. The addition of more placoderms and more catfish has cemented this hypothetical interrelationship over the past year.

Figure 1. Wuttagoonaspis from Ritchie 1973. Colors added here.

Figure 1. Wuttagoonaspis from Ritchie 1973. Colors added here. Compare to Clarias in figure 2.

Taxon exclusion
prevented these two from nesting together previously.

FIgure 1. Clarias, the walking catfish is a living placoderm with skull bones colorized as homologs of those in Entelognathus (Fig. 2). Here the mandible shifts forward and the opercular shifts backwards relative to Entelongnathus in the Silurian.

FIgure 2. Clarias, the walking catfish is a living placoderm with skull bones colorized as homologs of those with tetrapods. Compare to Wuttagoonaspis in figure 1. Note the lack of a maxilla.

The LRT does not care
what era a taxon lived in, or where it traditionally nests. When taxon exclusion is minimized the LRT recovers the most parsimonious tree for the list of taxa and characters it has to work with. By letting taxa that have never been tested together before, get tested together, sometimes novel and overlooked relationships are recovered.

Figure x. Subset of the LRT, focusing on fish for July 2020.

Figure x. Subset of the LRT, focusing on fish for July 2020.

Something like the LRT has been long sought
by vertebrate paleontologists. Now that they have it, what are they going to do with it?


References
Ritchie A 1973. Wuttagoonaspis gen. nov., an unusual arthrodire from the Devonian of Western New South Wales, Australia. Palaeontographica 143:58–72.

 

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