Underwhelming Fossil Fish of the Month April 2017
By Mark Carnall, on 2 May 2017
Dearly beloved, we are gathered here today to witness the monthly union of a fossil fish and the acknowledgement of how underwhelming this fossil fish is, in holy blogimony, which is an honourable estate, that is not to be entered into unadvisedly or lightly, but reverently and soberly.
This month’s fossil fish, is what we call in the palaeontological trade “a bit of alright”, that is, it is aesthetically rather on the ‘girl you gonna make me sweat’ end of the fossil fish scale. Don’t claim you haven’t been warned as this month’s underwhelming fossil fish is revealed before you as it will be in three, two, one…
According to the label for this specimen, this is an example of Cheirolepis trailli, the first non-ghost Cheirolepis fossil to appear in this series. Cheirolepis is an extinct genus of freshwater ray-finned fish that lived in Devonian period. Cheirolepis trailli was the first species of Cheirolepis to be named and was described from fossils from Scotland, which is where this specimen is reportedly from. Cheirolepis is thought to have been an active predator that relied on sight to hunt.
Preservation From the looks of it, this specimen has been preserved inside a nice elliptical nodule which has been split in half to show us this lovely fish and then this half seems to have also been split in two too. This specimen hasn’t been preserved in a huge amount of detail: the rough shape of the fish can kinda be discerned if you squint, from a distance and have a bit of imagination. On the left hand side are what I presume to be the slightly discombobulated bones of the head although I’d be hard pressed to be able to pick out a single identifiable element to try to work out which way up this fish should be. It’s a times like these that a palaeo-artistic reconstruction by an up-and-coming-everybody-is-talking-about-them-deceptively-young-looking-palaeo-artist might come in really handy….
No? Oh. That usually works. Err okay then, Scientific Research JOY UPON JOYS, the database entry for this fossil suggests that it has been figured a number of times which I hoped may be an actual first for underwhelming fossil fish of the month. According to the database this specimen is “References Figd. 1925 Proc. zool. Soc. Moy Thomas p.107, Romer p 48,50,55 Traite de Pal. 43”. Which is actually three different references. I think. Alas, after hunting down some of these, this note merely indicates that Cheirolepis trailli is figured in general, not this specific specimen. Which although disappointing, makes sense because, well you look at the fossil. I’m not sure what there is to figure. Our old friend D.M.S Watson, wrote about Cheirolepis trailli an number of times but sadly this specimen which was in his collection seems to have been less useful than specimens in the British Museum (Natural History) and in Manchester. In putting together some of the text figures, he does mention that reconstructions were made from specimens at other museums and “in my own possession” which doesn’t entirely rule out this specimen (Watson 1925). If we’re really clutching at straws.
In general, Cheirolepis has been of scientific interest as an early actinopterygian (the most diverse group of vertebrates, the ‘ray-finned’ fish) genus, however, more often than not these fossils leave scientists scratching their heads when it comes to questions of evolution of cranial dermal bone and enamel. Cheirolepis is one of the earliest fossil fish known to possess the standard arrangement of bones in the cranium, which is seen in all ray-finned fish today, so give a nod to Cheirolepis the next time you see a trout head.
In Society I think this is a first for Underwhelming Fossil Fish of the Month, this fossil actually has had some impact on wider society. The more eagle-eyederer of you out there will have spotted this fossil in the recent poster advertisements for Alien Covenant. Cheirolepis trailli was allegedly spotted by a talent scout who was on the hunt for colourless amorphous looking shapes for the striking advert and I think you’ll agree, Cheirolepis trailli really fits the bill and ‘makes’ the aesthetic of the marketing campaign.
In Society 7
Watson, D.M.S. 1925. The Structure of Certain Palaeoniscids and the Relationships of the Group with other Bony Fish. Proceedings of the Zoological Society of London. LIV. 815-870.
Mark Carnall is the Collections Manager (Life Collections) at the Oxford University Museum of Natural History, and former Curator of the Grant Museum