Underwhelming Fossil Fish of the Month: June 2016
By Mark Carnall, on 30 June 2016
It has been a month. That is for sure. But I tell you who won’t be worrying about their future, or screaming into a brown paper bag, or asking if anyone competent is actually in charge of anything at a time when that kind of thing seems very important. Underwhelming fossil fish in museum drawers that’s who.
That’s right, we’re back with our monthly series, taking time away from the chaotic world to look at and if you’re feeling sassy perhaps shrug a shoulder or two at an underwhelming fossil fish from the Grant Museum of Zoology’s collections. The worst a fossil fish has to look forward to is nothing as fossil fish cannot contemplate anything. They are made of stone. Those lucky fishy fossily fellows.
This month’s fossil fish, out of pure chance, is from John o’ Groats. John o’ Groats used to be a man but it is now a village in Scotland. John o’ Groats currently lies on Britain’s northeastern tip and is famous for being one end of the longest trip you could take between two British settlements, the other end being Land’s End in Cornwall. This fossil was once a complete fish but sadly the taphonomic processes have ‘made it great again’ meaning it is now fragmented, no longer whole and far less interesting for it too, fortunately for us.
This month we’ve got overlabelling highlighting historical less-than-best practice in museum labelling which I know is at the forefront of all of our minds at the moment. Let’s have a look shall we?
Keen eyed readers will note the return of last month’s scale bar. Will it be used next month too? Tune in to find out!
Here’s a close up shot that is barely different from the above one, just to show that there really isn’t that much to see here. Move along. The label for this specimen identifies is as the rear half of a fish in the genus Pentlandia
No, Pentlandia. Pentlandia is a sarcopterygian fish, or lobe-finned fish, living members being the coelacanths and lungfish. Sarcopterygians are thought to be the group of fish which all tetrapods have descended from via the medium of amphibians. So that includes you, me, the dog, a seagull, all the seagulls, whales, crocodiles and bongos to name a few. This Pentlandia fossil was probably collected from the world famous, John o’ Groats fish bed. John o’ Groats is (probably) not a bizarre kind of bed used by a man called John o’ Groats but it is a lithographic unit known for yielding fossil fish. The John o’ Groats fish bed is Givetian (pronounced ‘Give it Ian’ but only in a Welsh accent) in age, very roughly 387.7 ± 0.8 million years ago to 382.7 ± 1.6 million years ago.
Preservation The really interesting thing about sarcopterygian fish is their stubby lobed pelvic and pectoral fins which is proposed to have been the origin of the limbs we know and love today, as opposed to less flexible fins of other kinds of fish. Handily, none of these are preserved here. What we have here is the outline of the [opposite of business] end of the animal, the tail fins and second dorsal laying on top of each other, in the view above we’re looking at the underside of the specimen at the anal fin. Possibly. It’s difficult to tell if only there was a way that a creative type could attempt to clarify it with a reconstruction.
So that’s that clear.
Research Despite not being by any means a rare species to be found from the John o’ Groats fish bed, many are preserved in such a way that the internal anatomy is difficult to discern, or as with this specimen, the ever so interesting pectoral or pelvic fins are not preserved. As it seems is the case with all Scottish fossil fish, Pentlandia was examined by the grant Museum’s own fossil fish legend D.M.S Watson and no stranger to this series, Ramsay Traquair. Traquair originally described Pentlandia as Dipterus macropterus in 1889 noting the long anal fin (Traquair 1889). Watson and a colleague then reckoned the anal fin and other mysterious features were distinct enough to erect a new genus, Pentlandia (Paper I couldn’t find a copy of 1916). In the intervening years between now and then, it’s been tough for Pentlandia. It got some coverage in 1995 when it was brutally ruled out as a possible maker of a new kind of conical burrow trace fossil, Cornulatichnus edayensis in a mystery that had the nation gripped (Carroll and Trewin 1995). More recently colleagues from Oxford University and the Natural History Museum London published a nice paper in the Star Trekesquely named FRONTIERS IN EARTH SCIENCE detailing a rare well-preserved fossil showing the skeleton of the pectoral-fin (Jude et al. 2014). If you’re into preaxial finwebs and pectoral mesomeres, I can tell you, it’s worth a read.
In Society. Even if you’ve been hiding under a rock, you’ll know that Pentlandia never hit the big time. It never really made and impact on the world, so let’s take some time to look at HYPE FANTASTIC FIELD LABELS.
In addition to the cryptic ‘rello’ label which is not at all C1211 upside down, This is a rare example of what looks to be a field label. In a museum context, we take the time to properly label specimens
using electrical tape but in the Wild West of the field, information needs to be recorded. It needs to be recorded STAT. We’ve got different pens, we’ve got diagonal text, numbers in circles, numbers with apostrophes as well as instructions for the long term retention of this specimen for science. What does the 2 mean? Is the ’69 1969? 1869? THIS IS WHY WE WRITE THE FULL DATE ALL THE TIME IN MUSEUMS. ALL THE TIME. Fortunately, for science, this specimen was spared the doorstop/rockery fate with the KEEP in all caps and this snap decision made in the maelstrom of fieldwork has brought us this specimen today. For us to be utterly underwhelmed by. Thanks anonymous field scientist, we couldn’t have done it without you.
In Society 0
Carroll, S. and Trewin, N. (1995). Cornulatichnus: a new trace fossil from the Old Red Sandstone of Orkney. Scottish Journal of Geology 31, (1), 37-41.
Jude, E., Johanson, Z., Kearsley, A. and Friedman, M. (2014). Early evolution of the lungfish pectoral-fin endoskeleton: evidence from the Middle Devonian (Givetian) Pentlandia macroptera. Frontiers in Earth Science 12.
Paper I couldn’t find a copy of (1916). A.K.A. Watson, D. M. S., and Day, H. (1916). Notes on some Palaeozoic fishes. Mem. Proc. Manchest. Lit. Philos. Soc. 60, 1–47.
R. H. Traquair (1889). I.—On a New Species of Dipterus. Geological Magazine (Decade III), 6, pp 97-99.
Mark Carnall is the Collections Manager (Life Collections) at the Oxford University Museum of Natural History, and former Curator of the Grant Museum