Thursday 16 November 2017

PrehiScotInktoberfest Day 16: Akmonistion zangerli

PrehiScotInktoberfest 16 stays in the sea, but jumps forward a bit in time to the early Carboniferous period, 360 - 298 million years ago. We are in what is now Bearsden - which, like much of Scotland in that period, was underwater. Thus far, only one creature has been discovered from Bearsden, and what a beastie it is!

Akmonistion zangerli ("Zangerl's Anvil Sail") is weel kent as the Bearsden Shark: more accurately, Akmo is a chimaera, a cartilaginous fishie that's a cousin to the sharks and rays. Since modern chimaeras are benthic bottom feeders, it stands to reason Akmo lived a similar life. At 3 feet long, Akmo isn't the largest of marine creatures - it isn't even the largest prehistoric fish, as we'll soon find out - but it's definitely one of the most distinctive.

If palaeontologists could ask Akmo a question (and if Akmo could answer), it would surely be "Ho, Akmo, whit's wi' thon hing oan yer heid?" If one was a Scottish palaeontologist, at least. The weird anvil-shaped fin from which it derives its name is the subject of much speculation: is it a display, a defense mechanism, a dimorphism? The name for this... thing is The Spine-Brush Complex. The top surface was covered in trabecular dentine, the same substance teeth are made of, and which are speculated to have been inflatable. Somehow. Sharks are weird at the best of times.

Not only are those dentines present on the SBC, they cover a patch of Akmo's head, giving the impression of a spiky haircut. Thus far, it appears only mature male sharks had these features. Even the fins are bizarre: the pectoral fins have long "whips" attached near the body, whose purpose is just as unknown as the SBC.

The teeth are practically normal in comparison, bearing multiple cusps like other early sharks: the shape suggests they developed to catch and hold prey to be swallowed whole, rather than sliced and diced like with modern sharks. Bizarre appendages, spiky heads, horrendous teeth - definitely from Bearsden!

Perhaps most curious of all is the fact Akmo is the only creature found in Bearsden. What did it eat? Did anything eat it? None can say for sure.

"Wheee, it's magic havin' the ocean tae oorsels, is it naw, Akmo?"

"Aye, Akmo, pure deid braw!"

"Superb! Whit ye want tae eat?"

"Dinnae ken. Phone furra Chinese?"

No comments:

Post a Comment