Brindabellaspis, Diandongpetalichthys, Shearsbyaspis, Lunapsis and Kolymaspis

Diandongpetalichthys liaojiaoshanensis (Zhu et al. 1991; Early Devonian) is a petalichthid placoderm close to Lunaspis. The postorbital is restricted to the lower orbit. Jaws are lacking.

Kolymaspis sibirica (TsNIGR 7656 Brazeau et al 2023; Early Devonian, Siberia, 410 mya) nests with Diandongpetalichthys in the LRT. Note the more dorsal placement of the orbits. This is a jawless taxon that probably had pectoral lateral extensions.

Lunaspis heroldi (Broili 1929; latest Early Devonian, 405mya) is traditionally considered a petalichthyid placoderm. Here it nests with Qilinyu and Wutagoonaspis. The tail, missing from this fossil, was probabaly long and whip-like, as in rays. None of the specimens preserve mouth parts. Note the serrated leading edge of the pectoral fins.

Shearsbyaspis oepiki (Young 1984(5); Castiello and Brazeau 2018, Early Devonian, NHMUK P33580) is a 3D specimen of an anterior skull. The frontal is narrow but articulates with the nasal, distinct from Lunaspis.

Brazeau MD et al (6 co-authors) 2023. Fossil evidence for a pharyngeal origin of the vertebrate pectoral girdle. Nature https://doi.org/10.1038/s41586-023-06702-4

Broili F 1929. S. B. Bayer. Akad. Wiss., 1

Castiello M and Brazeau MD 2018. Neurocranial anatomy of the petalichthyid placoderm Shearsbyaspis oepiki Young revealed by X-ray computed microtomography. Palaeontology https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12345

Young G 1985. Further petalichthyid remains (Placoderm fishes, Early Devonian) from the Taemas-Wee Jasper region, New South Wales. Journal of Australian Geology & Geophysics 9: 121–131.

Zhu M 1991. New information on Diandongpetalichthys (Placodermi: Petalichthyida). Early vertebrates and related problems of evolutionary biology. Beijing: Science Press. 179–192.

Zhu et al. 2012. An antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates. Biology Letters Palaeontology 8:453–456.

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