Panxiosteidae is an extinct familyofarthrodire placoderms that lived during the Devonian period.
| Panxiosteidae ↓ | |
|---|---|
| |
| Various species of Plourdosteus | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | †Placodermi |
| Order: | †Arthrodira |
| Suborder: | †Brachythoraci |
| Clade: | †Eubrachythoraci |
| Clade: | †Pachyosteomorphi |
| Superfamily: | †Dunkleosteoidea |
| Family: | †Panxiosteidae Wang, 1979 |
| Genera | |
The family Panxiosteidae was erected by Wang in 1979. Members of the family are noted for showing morphologically intermediate traits between coccosteids and dunkleosteids.[1] In the 2010 Carr & Hlavin phylogenetic study, Panxiosteidae was recognized as the sister taxon to the family Dunkleosteidae, which together comprised the superfamily Dunkleosteoidea (one of the three major cladesofEubrachythoraci).[2]
The phylogeny of Panxiosteidae from the 2013 Zhu & Zhu study is shown in the cladogram below:[3]
| Eubrachythoraci | Pachyosteomorphi | |
However, the subsequent 2016 Zhu et al. study using a larger morphological dataset recovered Panxiosteidae well outside of Dunkleosteoidea, instead within Coccosteomorphi and then Coccosteoidea as the sister groupofCoccosteidae, as shown in the cladogram below:[1]