Tristichopteridae, Tristichopterus alatus
GRI #604-1

Phaneropleuridae, Pentlandia macroptera
GRI #604-2,3

This slab contains three specimens of fish from the Devonian layers of Orkney, Scotland. The specimen at the top, Tristichopterus, was a small, lobe-finned fish, that reached 30-60 cm in length. It was quite similar to another lobe-finned fish, Eusthenopteron, but the two genera differ in size and some details of the skeleton. In both fish, the tail fin was almost symmetrical (diphycercal). First discovered in northern Scotland, it has also been found in Belgium, the Baltic region, Australia, and Greenland (Olive et al., 2020).

Seen at the center (head partially missing, ventral side to the top) and bottom of the slab, Pentlandia is an extinct lungfish that grew to 30-40 cm long. It had an asymmetrical tail fin, and a large posterior dorsal fin. Its scales did not have a covering of cosmine, unlike most of the other lobe-finned fish (Dipnoans, 2022). It has been found in Devonian sediments of northern Scotland and in Silurian sediments in Norway and Wisconsin, USA (Paleobiology Database, n.d.).

References:

Dipnoans (2022) Landscapes of Orkney. Available at: https://orkneylandscapes.org/orkney/dipnoans/ (Accessed: August 2024).

Olive, S. et al. (2020) Tristichopterids (Sarcopterygii, Tetrapodomorpha) from the Upper Devonian tetrapod-bearing locality of Strud (Belgium, upper Famennian), with phylogenetic and paleobiogeographic considerations. Journal of Vertebrate Paleontology, 40(1), pp. 1-53.

Paleobiology Database (no date) Pentlandia, The Paleobiology Database. Available at: https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=377341 (Accessed: August 2024).