4 Stories

This week was jam-packed with news, so instead of only talking about one story, I’m going to cover 4 of them.

First: A new catfish from the Upper Eocene (56-33 million years ago) of Egypt. This [paper] was published by lead author Sanaa El-Sayed, who is now the first woman from the middle east to lead an international vertebrate paleontology paper. She describes the oldest marine catfish from the Eocene, which she named Qarmountus hitanensis (“the catfish from Hitan”). The specimen includes much of the head and the shoulders. It comes from a site called Wadi El-Hitan, which translates to the Valley of the Whales. Because it is only one specimen, we will need to find more before really understanding how it is related to other catfishes.

Figure 2 from the paper showing the new catfish fossil.

Second: A new fossil penguin from New Zealand. This [paper] describes the foot of a new penguin from the mid-Paleocene (66-56 million years ago). The size of the foot is larger than that of Waimanu, an extinct penguin the size of the modern emperor penguin (4 feet tall). Because it’s from the mid-Paleocene, it’s one of the oldest penguins known. Its giant size tells us that penguins became giant early in their evolution and stayed that way for 30 million years.

Figure 1 from the paper showing the new penguin fossil.

Third: The debate about Tully Monster continues. Last year I wrote about [this study] that said that Tully Monster had a notochord, making it a vertebrate. [This study] came out at the same time showing that Tully Monster has eyes like a vertebrate. The authors found that Tully’s eyes had melanosomes (pigment forming cells) in 2 layers. These 2 layers form a Retinal Pigment Epithelium (a fancy name for the cell layers that give the retina, which senses vision, nutrients). These layers are only found in vertebrates, lending more evidence that Tully is a vertebrate. Now a new [paper] contradicts the first study, and argues that the structures the authors found in the first study are also found in groups that aren’t vertebrates. The latest study does not say anything about the eyes, though, so there is still evidence towards Tully Monster being a vertebrate.

Figure 1 from the paper showing the Tully Monster.

Fourth: I’m writing a book with two colleagues (Abby West and Amy Gardiner)! Last week I launched a kickstarter project, called [She Found Fossils] to fund the publication of this project. The book is for children and it details the history women in paleontology, present diversity, and up-and-coming students. The book will be available in English and Spanish, and potentially some other languages depending on how much money we raise. Check it out!

Original art from Amy Gardiner of Mary Anning.

A Tale of Two Fishes (Part 2)

Our Tale of Two Fishes continues today with an exciting [article] that came out in mid-March (2016). The article talks about the Tully Monster (Tullimonstrom gregarium), the state fossil of Illinois (USA), and a particularly difficult fossil to understand.

TullyMonster

The Tully Monster is found in sediments that are from the Carboniferous, about 300 million years ago. That’s about half way through the Paleozoic Era (around 540-250 million years ago), the era before the Mesozoic (famous for being filled with dinosaurs). You’ll notice we count time backwards. This is because we dig downwards to find fossils, and if the surface of the ground is present day (= 0 million years ago), then downwards is older.

Time Scale

The Phanerozoic – the time of visible life.

Compare to all of Earth’s history:

geologic earth time

The Tully Monster is usually found as an impression inside a rock. We have thousands of them preserved and each look pretty similar to each other, so we know that it was definitely an animal. The problem was figuring out what kind of animal it was. Based on similarity with other animals, paleontologists had grouped the Tully Monster with molluscs (the group containing snails, clams, squid, slugs, and more), arthropods (insects, spiders, lobsters, trilobites, scorpions, horseshoe crabs, and more), and conodonts (weird early fish that were only known from individual teeth for a long time). Those are three radically different types of animals, none of which really suited the Tully Monster.

Moll Anthro Cono

Molluscs on the left, arthropods on the top right, conodonts on the bottom right.

The new study examined over 1200 specimens of the Tully Monster and discovered that it has all of the body parts that define vertebrates. These include:

  • Notochord (stiff rod in the back that supports the body – develops into our spinal column)
  • Gill pouches (support gills in fish, develop in us but are reabsorbed during growth in the womb)
  • Muscular body segments (we all have these, best seen in the fish you might eat)

There are more, but these three features must be seen in an animal to define it as a vertebrate. The authors also performed a computer analysis to determine the Tully Monster’s position in the vertebrate evolutionary tree and found that it is most closely related to lampreys and their relatives.

If you’ve never seen a lamprey, they are long, plain looking fish.

12345, Tue Jun 11, 2002, 10:58:11 AM, 8C, 2230x3302, (193+477), 50%, A. I. Basic, 1/100 s, R79, G67, B79

Until you look at their mouth:

lamprey mouth

So, the Tully Monster was misunderstood in many ways until this study showed that they are early fish. And that concludes our Tale of Two Fishes.