FRESH FISH CONNOISSEURS: THE AMMONITES

HORNBY ISLAND: LAMBERT FORMATION

The fossils of Hornby Island off the coast of Vancouver Island contain some of the best preserved fossils in British Columbia. Many species of ammonites (mainly Pachydiscus), crabs, bivalves, sharks teeth, echinoids, wood and bone can be found in the Cretaceous shales and concretions of the Lambert Formation at Collishaw Point

AMMONITES OF SOKOJA, MADAGASCAR

There is delightful suturing on this lovely ammonite, Holcophylloceras mediterraneum, (Neumayr 1871) from Late Jurassic (Oxfordian) deposits near Sokoja, Madagasgar.

The shells had many chambers divided by walls called septa. The chambers were connected by a tube called a siphuncle which allowed for the control of buoyancy with the hollow inner chambers of the shell acting as air tanks to help them float.

We can see the edges of this specimen's shell where it would have continued out to the last chamber, the body chamber, where the ammonite lived. Picture a squid or octopus, now add a shell and a ton of water. That's him!

They were prolific breeders that evolved rapidly. If you could cast a fishing line into our ancient seas, it is likely that you would hook an ammonite, not a fish. They were prolific back in the day, living (and sometimes dying) in schools in oceans around the globe. We find ammonite fossils (and plenty of them) in sedimentary rock from all over the world.

In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past.

For this reason, they make excellent index fossils. An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers rock to match up to specific geologic time periods, rather the way we use tree-rings to date trees. A handy way to compare fossils and date strata across the globe.

BLUE JAYS: KWASK'WAS

If you live in North American, there is a high probability that you have seen or heard the bird song of the Blue jay, Cyanocitta cristata (Linnaeus, 1758).

Blue Jays are in the family Corvidae — along with crows, ravens, rooks, magpies and jackdaws. They belong to a lineage of birds first seen in the Miocene — 25 million years ago. 

These beautifully plumed, blue, black and white birds can be found across southern Canada down to Florida. The distinctive blue you see in their feathers is a trick of the light. Their pigment, melanin, is actually a rather dull brown. The blue you see is caused by scattering light through modified cells on the surface of the feather as wee barbs.

Blue jays like to dine on nuts, seeds, suet, arthropods and some small vertebrates. 

If you are attempting to lure them to your yard with a bird feeder, they prefer those mounted on trays or posts versus hanging feeders. They will eat most anything you have on offer but sunflower seeds and peanuts are their favourites. 

They have a fondness for acorns and have been credited with helping expand the range of oak trees as the ice melted after the last glacial period.  

Their Binomial name, Cyanocitta cristata means, crested, blue chattering bird. I might have amended that to something less flattering, working in a Latin word or two for shrieks and screams — voce et gemitu or ululo et quiritor. While their plumage is a visual feast, their bird chatter leaves something to be desired. 

Their cries are quite helpful if you are an animal living nearby and concerned about predators. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, a Blue Jay is known as kwa̱skwa̱s. 

The Kwak’wala word for blue is dzasa and cry is ḵ̕was'id. For interest, the word for bird song in Kwak'wala is t̕sa̱sḵwana.