Belemnites and dinosaur age global warming


This 2006 video says about itself:

A short video introducing belemnites which were extinct cousins of the squid, octopus and cuttlefish.

From the University of Erlangen-Nuremberg in Germany:

Why organisms shrink in a warming world

March 9, 2020

Everyone is talking about global warming. A team of palaeontologists at GeoZentrum Nordbayern at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) has recently investigated how prehistoric organisms reacted to climate change, basing their research on belemnites.

These shrunk significantly when the water temperature rose as a result of volcanic activity approximately 183 million years ago, during the period known as the Toarcian. The FAU research team published their results in the online publication Royal Society Open Science.

‘Belemnites are particularly interesting, as they were very widespread for a long time and are closely related to the squid of today,’ explains palaeontologist Dr. Patricia Rita. ‘Their fossilised remains, for example the rostrum, can be used to make reliable observations.’ Within the context of the DFG-funded research project ‘Temperature-related stresses as a unifying principle in ancient extinctions,’ the hypothesis was confirmed that climate has a significant influence on the morphology of adult aquatic organisms. The body size of dominant species fell by an average of up to 40 percent.

The team of researchers believe that this Lilliput effect was a precursor to the later extinction of the animals. It is still unclear whether rises in temperature influenced the organisms’ metabolism directly or indirectly, for example due to a shortage of food sources.

Giant squid genome research


This 2015 video says about itself:

A giant Architeuthis dux squid was caught on camera when it swam into a harbor in Japan on Christmas Eve. The young squid is estimated to be 12 feet long, and scientists say the species can reach over 40 feet in length.

From the Marine Biological Laboratory in the USA:

The mysterious, legendary giant squid’s genome is revealed

January 16, 2020

How did the monstrous giant squid — reaching school-bus size, with eyes as big as dinner plates and tentacles that can snatch prey 10 yards away — get so scarily big?

Today, important clues about the anatomy and evolution of the mysterious giant squid (Architeuthis dux) are revealed through publication of its full genome sequence by a University of Copenhagen-led team that includes scientist Caroline Albertin of the Marine Biological Laboratory (MBL), Woods Hole.

Giant squid are rarely sighted and have never been caught and kept alive, meaning their biology (even how they reproduce) is still largely a mystery. The genome sequence can provide important insight.

“In terms of their genes, we found the giant squid look a lot like other animals. This means we can study these truly bizarre animals to learn more about ourselves,” says Albertin, who in 2015 led the team that sequenced the first genome of a cephalopod (the group that includes squid, octopus, cuttlefish, and nautilus).

Led by Rute da Fonseca at University of Copenhagen, the team discovered that the giant squid genome is big: with an estimated 2.7 billion DNA base pairs, it’s about 90 percent the size of the human genome.

Albertin analyzed several ancient, well-known gene families in the giant squid, drawing comparisons with the four other cephalopod species that have been sequenced and with the human genome.

She found that important developmental genes in almost all animals (Hox and Wnt) were present in single copies only in the giant squid genome. That means this gigantic, invertebrate creature — long a source of sea-monster lore — did NOT get so big through whole-genome duplication, a strategy that evolution took long ago to increase the size of vertebrates.

So, knowing how this squid species got so giant awaits further probing of its genome.

“A genome is a first step for answering a lot of questions about the biology of these very weird animals,” Albertin said, such as how they acquired the largest brain among the invertebrates, their sophisticated behaviors and agility, and their incredible skill at instantaneous camouflage.

“While cephalopods have many complex and elaborate features, they are thought to have evolved independently of the vertebrates. By comparing their genomes we can ask, ‘Are cephalopods and vertebrates built the same way or are they built differently?'” Albertin says.

Albertin also identified more than 100 genes in the protocadherin family — typically not found in abundance in invertebrates — in the giant squid genome.

“Protocadherins are thought to be important in wiring up a complicated brain correctly,” she says. “They were thought they were a vertebrate innovation, so we were really surprised when we found more than 100 of them in the octopus genome (in 2015). That seemed like a smoking gun to how you make a complicated brain. And we have found a similar expansion of protocadherins in the giant squid, as well.”

Lastly, she analyzed a gene family that (so far) is unique to cephalopods, called reflectins. “Reflectins encode a protein that is involved in making iridescence. Color is an important part of camouflage, so we are trying to understand what this gene family is doing and how it works,” Albertin says.

“Having this giant squid genome is an important node in helping us understand what makes a cephalopod a cephalopod. And it also can help us understand how new and novel genes arise in evolution and development.”

Deep-sea pink octopuses, new research


This 2014 video from the USA says about itself:

Researchers at the Monterey Bay Aquarium Research Institute (MBARI) have observed a deep-sea octopus brooding its eggs for four and one-half years—much longer than any other known animal. Throughout this time, the female kept the eggs clean and guarded them from predators. This amazing feat represents an evolutionary balancing act between the benefits to the young octopuses of having plenty of time to develop within their eggs, and their mother’s ability to survive for years with little or no food. Although long-term observations of deep-sea animals are rare, the researchers propose that extended brooding periods may be common in the deep sea. Such extended life stages would need to be taken into account in assessing the effects of human activities on deep-sea animals. In any case, this strategy has apparently worked for Graneledone (boreo)pacifica—it is one of the most common deep-sea octopuses in the Northeastern Pacific.

Video producer: Susan von Thun
Script and narration: Bruce Robison
Production support: Nancy Jacobsen Stout, Kyra Schlining, Lonny Lundsten, Linda Kuhnz

Scientific paper on this: here.

From the Field Museum in the USA:

The deeper these octopuses live, the wartier their skin

October 8, 2019

Deep beneath the ocean’s surface, surprisingly cute warty pink octopuses creep along the seafloor. But not all these octopuses look alike. While we humans love a good “Is your skin oily, dry, or combination?” quiz, members of one octopus species take variations in skin texture to a whole new level. Some have outrageous warts, while others appear nearly smooth-skinned. Scientists weren’t sure if these octopuses were even members of the same species, and they didn’t know how to explain the differences in the animals’ looks. But in a new study, scientists cracked the case: the deeper in the ocean the octopuses live, the bumpier their skin and the smaller their bodies. DNA revealed even though the octopuses looked different, they were the same species.

“If I had only two of these animals that looked very different, I would say, ‘Well, they’re different species, for sure.’ But variation inside animal species can sometimes fool you,” says Janet Voight, associate curator of zoology at the Field Museum and the lead author of the paper in the Bulletin of Marine Science. “That’s why we need to look at multiple specimens of species to see, does that first reaction based on two specimens make sense?”

To figure out if the smooth and warty octopuses were the same species, the scientists examined 50 specimens that were classified as Graneledone pacifica — the Pacific warty octopus. Plunging deep into the ocean in ALVIN, a human-occupied submersible vehicle, Voight collected some of the octopuses from the Northeast Pacific Ocean. The team also studied specimens loaned from the University of Miami Marine Laboratory and the California Academy of Sciences. They looked at specimens from up and down the Pacific, from as far north as Washington State to as far south as Monterey, California, and from depths ranging from 3,660 feet to more than 9,000 feet below the ocean’s surface.

The researchers counted the number of warts in a line across each octopus’s back and its head and the number of suckers on their arms. They found that the octopuses from deeper in the ocean looked different from their shallower counterparts. The deep-sea specimens were smaller, with fewer arm suckers, and, most noticeably, bumpier skin than those from shallower depths. The thing is, there weren’t two distinct groups; the animals’ appearances changed according to how deep they live. Comparing the octopuses’ DNA sequences revealed only minor differences, supporting the idea that they were all the same species, despite looking so different.

Sometimes when animals look different from each other, scientists can be tempted to jump the gun and declare them separate species — especially in the deep sea, where very little is known about animal life and scientists often don’t have many specimens to compare. But looking different doesn’t necessarily mean that animals are members of different species; take chihuahuas’ and Great Danes’, which are both the same species of Canis lupus familiaris, dogs, different appearances are due to selective breeding by humans, but in the case of the warty octopuses in this study, their different appearances seem to result from environmental influences, because their appearance changes depending on where the octopuses are from.

Scientists aren’t sure why the variations in skin texture occur with depth. But they do have a hunch about the size difference.

Voight thinks that these octopuses usually eat creatures from the sediment on the ocean floor, passing food from sucker to sucker and then crushing their prey like popcorn. “There’s less food as you get deeper in the ocean. So these animals have to work harder to find food to eat. And that means at the end of their lives, they’ll be smaller than animals who have more food. If you’re a female who’s going to lay eggs at the end of your life, maybe your eggs will be smaller” says Voight. Smaller eggs mean smaller hatchlings.

Support for this hypothesis comes from the number of suckers on the males’ arm that transfers sperm packets to females. Earlier research by Voight found that male hatchlings have a full-formed arm with all its suckers in place. The researchers documented that the number of suckers on this arm was way smaller in males from greater depth, and Voight hypothesizes it relates to egg size.

“The octopus hatchlings in shallower water, only 3,660 feet, are bigger. Their eggs had more yolk. As the embryos grew, they developed farther inside the egg than the ones from 9,000 feet, who were developing in smaller eggs. They had less energy to fuel their growth before they left the egg, so they made fewer suckers,” says Voight. Seeing these physical manifestations of octopuses’ food limitation provides a hint of how they might fare as climate change progresses and the octopuses’ food supply fluctuates.

Voight notes that this study, which shows that different-looking octopuses can still be the same genetic species, could help researchers down the line trying to identify life forms in the deep sea. Remotely operated vehicles collect video footage of the ocean floor, and it can be used to estimate the number of species present — if we know what they look like. That’s why, Voight says, it’s so important to examine specimens in person and use characteristics you can’t see on video to identify species boundaries.

“There’s still just so much we don’t know about the deep sea. We need to be able to understand the information that’s becoming available from ROV footage. And we can only do it by knowing what the animals look like.”