Tristichopterus alatus Egerton

Complete fish in lateral view.

Reconstruction by M.J. Newman ©.

Complete fish in lateral view.

Reconstruction (after Traquair, 1875).

Specimen in lateral view.

This fish is from the youngest fish-bearing Subgroup on Orkney, the Eday flags. There is a great deal of resemblance with the well know species Eusthenoptheron foordi  from the Upper Devonian of Miguasha, Canada. The species Eustenopteron foordi has been described by Jarvik in great detail in several publications.

It was a very fast swimming top predator. Probably the dipnoan Pentlandia macroptera was its prey.

Partly weathered tail showing the fin rays and the fin supports (collection F.V.C.).

Drawing of the tail (after Egerton, 1861).

Drawing of specimen (after Egerton, 1861).

Reconstruction (after Watson, 1935) ©.

Reconstruction of head (after Traquair, 1875).

Head of Tristichopterus: E: eye, Lj: lower jaw, O: opercular, P: parietal, PP: post parietal.

Reconstruction of pectoral fin and cleithrum (after Traquair, 1875).

Together with Eusthenopteron, these tetrapodamorph fishes were the first that showed a pectoral and pelvic fin bone structure that made scientists hypothesize that these fishes could be related to the first vertebrate land animals. They thought that the two paired fins would eventually evolve into the paired limbs.