Showing posts with label extinction. Show all posts
Showing posts with label extinction. Show all posts

Monday, April 29, 2024

WOOLLY MAMMOTHS: ANCIENT SNOW POUGHS

Woolly Mammoths, Mammuthus primigenius,  have always held wonder for me. These massive, hairy — and likely very smelly beasts — lived alongside us for a time. 

If you stood beside him and reached way up, you might be able to touch his tusks but likely not reach up to his mouth or even his eyes. 

He had a shaggy coat of light or dark coloured hair with long outer hair strands covering a dense thick undercoat. His oil glands would have worked overtime to secrete oils, giving him natural waterproofing. Some of the hair strands we have recovered are more than a meter in length. These behemoth proboscideans boasted long, curved tusks, little ears, short tails and grazed on leaves, shrubs and grasses that would have been hard work to get at as much of his world was covered in ice and snow during his reign.

We first see Woolly Mammoths in northeastern Siberia dating back 700,000 years. We find them in East Asia as far back as 800,000 years ago. They arose from the massive steppe mammoths, Mammuthus trogontherii, slowly evolving traits we see in this older species to the mammoths we think of today. 

Over time, their body size shrank and their teeth and tusks evolved to take advantage of the tough vegetation available to those few animals who could chew their way through ice and snow and work these tundra grasses into a digestible form. 

The enamel plates of their cheek teeth multiplied while the enamel itself became thinner. Tusks slowly took on more of a curved to act as ploughs for the snow. 

Those smaller than their predecessors, they were still formidable. Their size offered protection against predators once full grown. Sadly for the juveniles, they offered tasty prey to big cats like Homotherium who roamed these ancient grasslands alongside them.

The Mammoths of the Steppe spread to the northern areas of Eurasia, down through Europe, into the British Isles to Spain and crossed over to populate North America via the Bering Isthmus. It was the lowered sea levels during the last Ice Age that exposed dry land between Asia and the Americas. Here in this flat, grassy treeless plain known as the Bering Land Bridge or Isthmus, animals, including humans, could migrate from Europe west into North America.

The woolly mammoth coexisted with our ancestors who made good use of their bones and tusks for tools, housing, art and food. The last of their lineage died out relatively recently on Wrangel Island until 4,000 years ago — a time when we were making our first harps and flutes in Egypt, dams, canals and stone sculptures in Sumer, using numbers for the first time and using tin to make tools.

Tuesday, March 5, 2024

LOTUS FLOWER FRUIT

Lotus Flower Fruit, Nelumbo
This beauty is the fruit of the lotus, Nelumbo. This specimen was found by Green River Stone (GRS) in early Eocene outcrops of the Fossil Lake Member of the Green River Formation. 

The awesome possums from GRS are based out of North Logan, Utah, USA and have unearthed some world-class specimens. They've found Nelumbo leaves over the years but this is their first fossil specimen of the fruit.

And what a specimen it is! The spectacularly preserved fruit measures 6-1/2" round. Here you can see both the part and counterpart in fine detail. Doug Miller of Green River Stone sent copies to me this past summer and a copy to the deeply awesome Kirk Johnson, resident palaeontologist over at the Smithsonian Institute, to confirm the identification.

There is another spectacular specimen from Fossil Butte National Monument. They shared photos of a Nelumbo just yesterday. Nelumbo is a genus of aquatic plants in the order Proteales found living in freshwater ponds. You'll recognize them as the emblem of India, Vietnam and many wellness centres.

Nelumbo Fruit, Green River Formation
There is residual disagreement over which family the genus should be placed in. Traditional classification systems recognized Nelumbo as part of the Nymphaeaceae, but traditional taxonomists were likely misled by convergent evolution associated with an evolutionary shift from a terrestrial to an aquatic lifestyle. 

In the older classification systems, it was recognized under the biological order Nymphaeales or Nelumbonales. Nelumbo is currently recognized as the only living genus in Nelumbonaceae, one of several distinctive families in the eudicot order of the Proteales. Its closest living relatives, the (Proteaceae and Platanaceae), are shrubs or trees.

Interestingly, these lovelies can thermoregulate, producing heat. Nelumbo uses the alternative oxidase pathway (AOX) to exchange electrons. Instead of using the typical cytochrome complex pathway most plants use to power mitochondria, they instead use their cyanide-resistant alternative. 

This is perhaps to generate a wee bit more scent in their blooms and attract more pollinators. The use of this thermogenic feature would have also allowed thermo-sensitive pollinators to seek out the plants at night and possibly use the cover of darkness to linger and mate.

So they functioned a bit little like a romantic evening meeting spot for lovers and a wee bit like the scent diffuser in your home. This lovely has an old lineage with fossil species in Eurasia and North America going back to the Cretaceous and represented in the Paleogene and Neogene. Photo Two: Doug Miller of Green River Stone Company