Porolepis, Styloichthys, Laccognathus and Holoptychius

Holoptychius serrulatus (Agassiz 1839, Cope 1897; Middle Devonian to Carboniferous, 50cm to 2.5m long) was found in marine sandstone and is a late-surviving sister to Porolepis. Tiny teeh lined the jaws. Large fangs descended from the palate.

Porolepis posnaniensis (Kade 1858, named by Woodward 1891; Early Devonian) was a large, slow-moving lobefin with small eyes, related to Holoptychius. Colors are tetrapod homologs often different than labels. The upper squamosal is here the postorbital.

Laccognathus panderi (Gross 1941,Vorobyeva 2006, Down et al. 2011; Middle to Late Devonian, 390-360mya) was a marine costal or lagoon bottom dweller with a wider skull, smaller eyes and large palatal and coronoid fangs. Note the tiny marginal teeth. The two external nares are confluent.

Styloichthys changae (Zhu and Yu 2002; IVPP V15542.1-6; Early Devonian, 420 mya) is considered the oldest coelocanth. Here this tiny, widet-head taxon with just patches of a premaxilla nests with similar, but larger and later taxa likeLaccognathus.

Cloutier R 1996. The primitive actinistian Miguashaia bureaui Schultze (Sarcopterygii). Pp. 227–247 in: Schultze H-P and Cloutier R editors. Devonian fishes and plants of Miguasha, Quebec, Canada. Dr. Friedrich Pfiel; München: 1996.

Cope ED 1897. On New Paleozoic Vertebrata from Illinois, Ohio and Pennsylvania. Proceedings of the American Philosophical Society 36:71-91.

Downs J., Daeschler E, Jenkins F Jr and Shubin N 2011. A New Species of Laccognathus (Sarcopterygii, Porolepiformes) from the Late Devonian of Ellesmere Island, Nunavut, Canada. Journal of Vertebrate Paleontology. 31 (5): 981–996.

Gross W 1941. Über den Unterkiefer einiger devonischer Crossopterygier.
Abhandlungen der Preußischen Akademie der Wissenschaften 7:1–51.

Kade G 1858. Ueber die devonischen Fischreste cines diluvial Blockes. Meseritz. pp.17-18.

Vorobyeva EI 2006. A new species of Laccognathus (Porolepiform Crossopterygii) from the Devonian of Latvia. Paleontol. J. Physorg.com. 40 (3): 312–322. doi:10.1134/S0031030106030129.

Woodward AS 1891. Catalogue of the Fossil Fishes in the British Museum (Natural History). Part II. Catalogue of the Fossil Fishes in the British Museum (Natural History) 2.

wiki/Porolepis
wiki/Holoptychus
wiki/Laccognathus
wiki/Styloichthys