#knightia

[transparentfossil]

4.25" Fossil Fish (Knightia) - Wyoming

[justgoji]

The high seas!

[hasellia]

Hasellia's rock collection 06.07.23

[drhoz]

The Great ACT-NSW-NZ Trip, 2023-2024 - Taranaki Ringplain

After Pohokura we spent a couple of days on the west coast of North Island - specifically, in the vicinity of Taranaki/Mt. Egmont, a young stratovolcano that is the most recent volcano in a long sequence of slowly migrating volcanism in the area. The hills to the northwest, and the plugs at the coast at New Plymouth, are all that remain of its predecessors. In fact, the entire ring of flattish and highly fertile land in Taranaki is the result of the repeated catastrophic collapse of the volcanoes over the last 1.75 million years.

The photo below was taken from Cape Egmont 30 kilometers from the volcano. Even out here there are layers of fridge-sized boulders deposited by the giant volcanic landslides.

The plugs at New Plymouth, 1.75 myo.

Historically, the area consisted of a narrow coastal plain covered by bracken, tutu, rewarewa and karaka trees, with anywhere not close to the coast covered in dense forest.

From about 1823 the Māori began having contact with European whalers and flax traders. English settlers were first dropped here in 1841, and within a year were trying to deal with plagues of the rats they brought with them.

The stuff we saw on the volcano itself I'll cover seperately, but there was no shortage of species in New Plymouth, along the coast, at Lake Mangamahoe, and where we were staying.

[earthstory]

Tour a full Fossil collection! Who has a better one in their house? Show off in the comments

[emeraldcityminerals]

Fossilized Knightia alta from the Green River Formation of Wyoming. 

[theriodont]

Knightia

I’ve had the incredible chance lately to do some work cataloguing my school’s fossil collection, and this has put fossils rather at the forefront of my mind in the past few days, so I figured I’d talk about that a bit. Specifically, I’m going to talk about Knightia.

You may not recognize the name, but I’m sure you recognize the fossil itself. You know those little fish fossils, the ones with one or a few brown fish outlines in a slab of rock that you see all the time in fossil shops? That’s Knightia.

Knightia is almost certainly the most common vertebrate fossil on the planet. It was very widespread in North America and Asia during the Eocene, when the Earth was much warmer than today and the mid-latitudes were very tropical, and it lived in warm, placid lakes, rivers and wetlands. This were very good conditions for fossilization -- a dead animal would sink to the mud-covered bottom and would be fairly quickly covered by soft sediments, protecting it form scavengers. Since there would be very little oxygen in the mud, the body wouldn’t rot easily, and would be very likely to fossilize with minimal damage or scattering of the remains.

Further, Knightia --  a schooling fish -- seems to have had a tendency to die in mass mortality events, with large schools all dropping dead at once. As a result, it’s actually fairly common to find massive numbers of these fish preserved in the same rock layer, scattered around randomly in huge clusters.

Today, the lakes and marshes where Knightia lived are preserved as layers of mudstones and limestones brimming with excellently preserved fossils of all kinds, and since Knightia was one of the most common animals there, their fossils are some of the most abundant.

In life, Knightia was a clupeid, a member of the herring family, and would have greatly resembled its saltwater relatives.

Naturally, it would’ve sat pretty low on the food chain, and its number would’ve meant it was almost certainly a staple prey item for almost every small and mid-level predator in the area: Knightia remains have been found in the bellies of fossils of almost every fish known to have lived in the area, including Knightia’s own larger relative, Diplomystus.

And there’s the long and short on Knightia. Personally, I find having a little extra information on a fossil I happen to own greatly increases the enjoyment I get out of it, don’t you think?

[transparentfossil]

26" Fossil Fish (Knightia) Mass Mortality Plate