Chase Brownstein @ChaseBrownstein Twitter profile

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Chase Brownstein

3 months

1/13 🚨🚨 I am so excited to present our new paper, six years in the making. Here, we provide the first strong evidence that there is a molecular mechanism behind the origins of living fossil lineages! #biology #science #paleontology

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Chase Brownstein

@ChaseBrownstein

5 months

1/14 🚨🚨 New preprint! Very excited to share our new study on the evolution of sexual parasitism and the invasion of the deep sea by anglerfishes! #biology #evolution #teamfish

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Chase Brownstein

@ChaseBrownstein

3 years

🧵IT'S OUT! I'm thrilled to share my study study on the dinosaurs of the Merchantville Formation, including the description of baby hadrosaurids and the return of the Dryptosauridae-the eastern US's own tyrannosaur family... #science #paleontology #biology #dinosaurs

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Chase Brownstein

@ChaseBrownstein

1 year

The reputation of dinosaur paleontology being in tatters due to a bunch of ego-driven men should be unsurprising to anyone who has looked at history, because that's been the case since forever!

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Chase Brownstein

@ChaseBrownstein

2 months

@lpachter

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Chase Brownstein

@ChaseBrownstein

2 years

1/7 ⚠️⚠️NEW PAPER! Excited to present my new paper-not one, but TWO new choristoderes-big amphibious reptiles-from the Paleogene of the US housed in @yalepeabody ! #science #paleontology

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Chase Brownstein

@ChaseBrownstein

3 months

7/13 By calculating rates of substitutions per site across a set of >1000 exon sequences in 481 species, we found a possible answer: gars have the slowest rates of molecular evolution in jawed vertebrates.

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Chase Brownstein

@ChaseBrownstein

2 years

#VelociraptorAwarenessDay Be Aware: Velociraptor has a WEIRD pneumatic skull

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Chase Brownstein

@ChaseBrownstein

3 months

"And it is in fresh water that we find seven genera of Ganoid fishes, remnants of a once preponderant order: and in fresh water we find some of the most anomalous forms now known in the world" - Darwin 1859 #livingfossils #gar #evolution #science

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Chase Brownstein

@ChaseBrownstein

3 months

4/13 We had noticed that in contradiction to essentially all other species, the two living genera of gars still hybridize despite diverging in 105 million years ago. These hybrids are near perfect intermediates b/w parental phenotypes!

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Chase Brownstein

@ChaseBrownstein

2 years

🧵1/9 The Bowfin Amia, the sole survivor of a 200-million year-old fish lineage, harbors HIDDEN SPECIES! Excited to announce the preprint of paper with @TJNear , @DaeminKim3 @SolomonRDavid and colleagues here: #Biology #Evolution #Bowfin #Fish

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Chase Brownstein

@ChaseBrownstein

2 years

🚨🚨 IT'S OUT! Two new Jurassic lizards known from exceptional skulls and braincases refine our understanding of the early evolution of squamates!!! #paleontology #evolution #Science

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Chase Brownstein

@ChaseBrownstein

3 months

2/13 Since the early days of modern biology, thinkers like Darwin realized that some living animals and plants seemed to show incredibly low species diversity given their age, as well as few differences from their fossil relatives.

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Chase Brownstein

@ChaseBrownstein

3 months

@SolomonRDavid @DaeminKim3 @LiandongYang Conclusion: Living fossils are a biological reality.

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Chase Brownstein

@ChaseBrownstein

2 years

1/8 🚨🚨🚨IT'S OUT! So excited to present the results of our research, which recognizes a second Bowfin species, Amia ocellicauda, and splits a 200-million-year long branch in two! #science #biology #evolution

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Chase Brownstein

@ChaseBrownstein

10 months

#FossilFriday Triceratops skin from the "Lane" specimen @hmns

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Chase Brownstein

@ChaseBrownstein

3 months

3/13 Yet, there has been no clear evidence for a mechanism behind this pattern, and the term 'living fossil' has fallen out of favor. In 2019, during our first meeting, @TJNear brought up the idea of investigating this pattern using gars, a clade of 7 'living fossil' fishes.

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Chase Brownstein

@ChaseBrownstein

3 months

6/13 This makes gars the oldest wild hybrid cross in eukaryotes by nearly 50 million years. How could barriers to hybrid viability and fertility fail to form over >100 million years?

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Chase Brownstein

@ChaseBrownstein

2 years

#fossifriday merry CRESTmas everyone

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Chase Brownstein

@ChaseBrownstein

3 months

10/13 And when we plot the divergence times of hybridizing species with the oldest known common ancestors among vertebrates against rates of molecular evolution found in our study, we find exactly this! 'Living fossils' are a (predicted) extreme in the mutation-speciation curve!

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Chase Brownstein

@ChaseBrownstein

3 months

12/13 By providing evidence for mechanisms behind long-term evolutionary stasis, we illuminate the 'other side' of the evolutionary story. We as biologists tend to focus on the species-rich clades, but to truly understand such patterns, we need to look across the spectrum!

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Chase Brownstein

@ChaseBrownstein

3 months

11/13 So, it appears that at least for some living fossils, a molecular mechanism is at play! Others may be accidents of history, like the tuatara surviving in isolation on New Zealand. For clades with the mechanism, we think that strong DNA repair machinery might be responsible!

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Chase Brownstein

@ChaseBrownstein

3 months

7/13 Along with sturgeons and paddlefishes, another clade known to produce viable hybrids from parents with ancient (>100 Ma) common ancestry, nearly half of all exons show no substitution differences among sister species that diverged over 5 million years ago!

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Chase Brownstein

@ChaseBrownstein

3 months

5/13 And when we sequenced and analyzed the wild hybrids, we found strong evidence for backcrossing, meaning some were fertile.

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Chase Brownstein

@ChaseBrownstein

1 month

1/6 ⏰⏰ New publication with @TJNear in @ZoolJLinnSoc ! We describe a big new fish from 10 million years after the impact that killed the dinosaurs. Introducing †Amia basiloides, or, as we've nicknamed it, the big a** bowfin! #fossils #paleontology

A giant bowfin from a Paleocene hothouse ecosystem in North America

Abstract. Aquatic biodiversity changed dramatically at the start of the Paleogene. Although comparatively little is known about global freshwater ecosystem

academic.oup.com

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Chase Brownstein

@ChaseBrownstein

8 days

1/10 ⏰⏰ The final version of our #anglerfish #evolution paper is out @CurrentBiology ! In it, we demonstrate how this clade rapidly assembled a unique trait-sexual parasitism-and secondarily invaded the open ocean in a manner reminiscent of whales!

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Chase Brownstein

@ChaseBrownstein

1 year

1/7🚨🚨 NEW PAPER! STOKED to share my work with @TJNear @Friedman_Lab @LiandongYang on the evolution of gars, a living fossil lineage! We combined phylogenomics, paleontology, and biogeography to investigate this ancient clade! #biology #phylogenetics

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Chase Brownstein

@ChaseBrownstein

2 years

1/10 IT'S OUT!!! So pleased to share this incredible fossil-a giant gar from literally <20 cm above the iridium layer! Meet Atractosteus grandei!

Royal Society Publishing

@RSocPublishing

2 years

New from @ChaseBrownstein => Giant gar from directly above the K–Pg boundary suggests healthy freshwater ecosystems existed within thousands of years of the asteroid impact - | #BiologyLetters #evolution #palaeontology

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Chase Brownstein

@ChaseBrownstein

1 year

Very excited to share a new publication with @TJNear and @FishHarrington chronicling the 300-million-year evolutionary story of lungfishes! Now in @JBiogeography !

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Chase Brownstein

@ChaseBrownstein

3 months

8/13 Even compared to other putative 'living fossil' lineages, gars are slow!

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Chase Brownstein

@ChaseBrownstein

2 years

TRICERATOPS HAD A BELLY BUTTON THE MOST IMPORTANT NEWS

Oldest preserved umbilical scar reveals dinosaurs had ‘belly buttons’ - BMC Biology

Background In egg-laying amniotes, the developing embryo is tethered to a number of the extraembryonic membranes including the yolk sac and allantois that deliver oxygen and nutrients and remove...

bmcbiol.biomedcentral.com

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Chase Brownstein

@ChaseBrownstein

3 months

9/13 How does this provide a mechanism for living fossils? Classic theory holds that speciation is in part a function of the mutation rate. A higher rate means more incompatibilities forming in isolated populations that come into secondary contact!

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Chase Brownstein

@ChaseBrownstein

6 years

For #FossilFriday , here’s the classic view of the first skull of Velociraptor ever found

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Chase Brownstein

@ChaseBrownstein

3 months

13/13 This study has been a huge part of my intellectual growth and study @Yale , and I have so many people to thank. First and foremost, my advisor, @TJNear . None of this work is possible without him! Thanks to @yalepeabody @kunhm for specimen access, and to my coauthors both ..

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Chase Brownstein

@ChaseBrownstein

3 years

Ornitholestes is a very cool taxon

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Chase Brownstein

@ChaseBrownstein

1 year

New paper! Pleased to describe this excellent coelacanth skull from the Dockum Group, and suggest that Bob Schaeffer was right about it's ID: #paleontology #FossilFriday

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Chase Brownstein

@ChaseBrownstein

4 months

There's morphological novelty, and then there's whatever the heck this is! Congrats to the authors on a superb publication

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Chase Brownstein

@ChaseBrownstein

11 months

🚨🚨 New paper! Pleased to introduce †Jupijkam paleofluvialis, Canada's first phytosaur species, from the collections of the @yalepeabody ! Find it at #science #fossils #paleontology

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Chase Brownstein

@ChaseBrownstein

6 years

Another for #FossilFriday , here’s a photo of the holotype skull of #Velociraptor @AMNH I got to examine a couple weeks back.

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Chase Brownstein

@ChaseBrownstein

4 months

🚨🚨New paper! Pleased to share my latest paper describing the partial, semi-articulated skeleton of a juvenile bird from the Lance Formation! This is a potential crown bird contemporary of Tyrannosaurus! #paleontology #fossils #science

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Chase Brownstein

@ChaseBrownstein

3 years

Excited to share my papers on dromaeosaurid pneumaticity and hadrosauromorphs from NJ have been officially published @ZoolJLinnSoc . Find them here: #paleontology #Evolution

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Chase Brownstein

@ChaseBrownstein

3 months

Congrats @SteveBrusatte and colleagues!

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Chase Brownstein

@ChaseBrownstein

4 years

Grand Staircase-Escalante and Bear's Ears PLEASE!

The Washington Post

@washingtonpost

4 years

Biden plans immediate flurry of executive orders to reverse Trump policies

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Chase Brownstein

@ChaseBrownstein

3 years

#FossilFriday the Dryptosauridae is the east coast's own family of tyrannosaurs. They are notable for their giant hand claws (found in Dryptosaurus) and oddly structured feet

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Chase Brownstein

@ChaseBrownstein

2 years

1/6 Excited to share the first paper resulting from my research on gars; say hello to †Cuneatus maximus, a new, big gar from Wyoming that crushed invertebrates 53 million years ago:

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Chase Brownstein

@ChaseBrownstein

1 year

@Bhmllr 1. Delma borea (this is a gecko) 2. Burton's legless lizard (this is a gecko) 3. Satanic leaf tailed gecko (you see where I am going)

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Chase Brownstein

@ChaseBrownstein

3 months

on ( @SolomonRDavid @DaeminKim3 @LiandongYang ) and off (Dan Maguigan, Brian Kreiser, Oliver Orr) twitter!

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Chase Brownstein

@ChaseBrownstein

6 months

Super excited to have worked on this study with @LizardManMeyer @reptiliferous @yalepeabody ! We describe a new species of stem-gecko from the Jurassic Morrison Formation, representing perhaps the first stem-gecko from North America!

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Chase Brownstein

@ChaseBrownstein

5 years

#VelociraptorAwarenessDay Here's the holotype skull

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Chase Brownstein

@ChaseBrownstein

7 months

Excited to share another new paper w/ @TJNear ! We reconstruct the evolutionary tree and timescale of diversification in Lampriformes, a clade of mainly pelagic fishes with bizarre body plans! #fish #biology #paleontology

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Chase Brownstein

@ChaseBrownstein

5 years

Thalassodromeus and Tupandactylus on display a few years ago @AMNH . Check out those crests! #FossilFriday

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Chase Brownstein

@ChaseBrownstein

2 years

An extraordinary †Diplomystus, a very big clupeomorph (the herring-anchovy group) from 50 million years ago in North America #FossilFriday

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Chase Brownstein

@ChaseBrownstein

1 year

Not your parents' "Archie" @yalepeabody skull of †Archelon ischyros, the biggest turtle ever

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Chase Brownstein

@ChaseBrownstein

2 years

#FossilFriday neck vertebra of a giant azhdarchid pterosaur from ~67 million years ago in New Jersey. This is only one of two azhdarchid bones known from Appalachia. Housed at @yalepeabody

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Chase Brownstein

@ChaseBrownstein

3 years

pure excellence in natural history illustration:

Gabriel N. U.

@SerpenIllus

3 years

So, apparently is making an appearance in some movie apparently (although you wouldn’t recognize it). Here is my take on this amazing Late Cretaceous South American carcharodontosaurid

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Chase Brownstein

@ChaseBrownstein

3 months

Press for our paper in Yale News!

Study of slowly evolving ‘living fossils’ reveals key genetic insights

Yale researchers have discovered evidence of why a fish group, considered “living fossils,” has existed largely unchanged for tens of millions of years.

news.yale.edu

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Chase Brownstein

@ChaseBrownstein

5 years

For this #FossilFriday , check out this amazingly preserved Tenontosaurus skull in the collections of the Yale Peabody Museum @yalepeabody

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Chase Brownstein

@ChaseBrownstein

3 years

Found these photos of the old @yalepeabody Ichthyornis mounts. I always found these very fun-you can see what crushing in Kansas chalk does to bird bones vs the reconstructed gray material

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Chase Brownstein

@ChaseBrownstein

3 years

1. BIG FINDINGS: (1) a fragmentary skeleton from about 80 million years ago in Delaware shares some features with a weird tyrannosaur called Dryptosaurus, which lived in New Jersey just before the asteroid hit and is known for its giant hand claws...

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Chase Brownstein

@ChaseBrownstein

10 months

#FossilFriday 'Snowmastodons' and ground sloths, Majungasaurus, and Triceratops in the @DenverMuseumNS !

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Chase Brownstein

@ChaseBrownstein

6 years

For #FossilFriday , here's the maxilla and dentary of the dromaeosaurid Deinonychus @yalepeabody . Check out those teeth!

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Chase Brownstein

@ChaseBrownstein

3 years

2. When features previously considered to be distinct in the foot of Dryptosaurus are included in an analysis of evolutionary relationships, it and the Delaware tyrannosaur form a group. This group is called Dryptosauridae, and its existence has been debated since the 1870s

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Chase Brownstein

@ChaseBrownstein

3 years

Anyone who says otherwise can unfollow me immediately

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Chase Brownstein

@ChaseBrownstein

1 year

According to this new paper: Crown placentals and crown gars are the same age basically.

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Chase Brownstein

@ChaseBrownstein

6 years

Skull of Tsaagan mangas, a close relative to Velociraptor, @AMNH #FossilFriday

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Chase Brownstein

@ChaseBrownstein

2 years

🚨🚨New paper alert! I describe evidence of very big (1.3+ m) sturgeons from the Paleogene of North America! Another indicator for healthy freshwater ecosystems in the aftermath of the Cretaceous-Paleogene mass extinction! #science #paleontology

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Chase Brownstein

@ChaseBrownstein

5 months

2023 was a great year for research and discovery! Here are some of our pubs from this year I'm most excited about!

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Chase Brownstein

@ChaseBrownstein

2 years

and just cus they are so cool! CT SCANSSS

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Chase Brownstein

@ChaseBrownstein

5 months

The best, and arguably first definite, crown caecilian fossil. Wow! Congrats to the authors

The first fossil record of an aquatic caecilian (Gymnophiona: Typhlonectidae)

Abstract. The lissamphibian clade Gymnophiona includes approximately 220 recognized modern species known by the English vernacular as caecilians and charac

academic.oup.com

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Chase Brownstein

@ChaseBrownstein

2 years

Coincidence?? I think NOT! from Yuan et al. 2022, PeerJ

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Chase Brownstein

@ChaseBrownstein

1 year

🚨🚨Very excited to share my new paper-a new phylogenetic dataset and hypothesis of syngnathoid evolution! Out now in @iobopen !

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Chase Brownstein

@ChaseBrownstein

6 years

This is a cast of the hand claw of Dryptosaurus aquilunguis @yalepeabody , a bizarre tyrannosaur from the Late Cretaceous of New Jersey. Unlike its more derived relative T.rex, Dryptosaurus had really big hands. #FossilFriday

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Chase Brownstein

@ChaseBrownstein

4 years

Happy to share a paper of mine was published today reviewing an interesting characteristic, pneumaticity, observable on the external surface of the skulls of birds and their dinosaurian cousins: #science #paleontology

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Chase Brownstein

@ChaseBrownstein

4 years

Super excited to announce my newest paper out in @PaleoSoc 's Journal of Paleontology with my friend and freshman roommate @Yale Immanuel!

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Chase Brownstein

@ChaseBrownstein

2 years

#WorldLizardDay The biggest lizards were lizards of the sea (Mosasauridae)

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Chase Brownstein

@ChaseBrownstein

1 year

🚨🚨 1/7 Excited to share another new paper with @TJNear ! We took a deep dive into another 'living fossil' lineage from eastern North America, the lampreys! #Biology #Phylogenetics #Fossils

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Chase Brownstein

@ChaseBrownstein

2 months

I’m putting together a team

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Chase Brownstein

@ChaseBrownstein

4 years

Some news I want to share. My paper in Historical Biology has been formally published after being in press for a bit. This project attempts to shed light on the last megafauna in Europe, and what the Romans and Greeks wrote of them #paleontology #megafauna

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Chase Brownstein

@ChaseBrownstein

2 years

Pleased to share that my description of †Cuneatus maximus sp. nov., the giant crusher gar, was chosen as an editor's choice paper at Acta Paleeontologica Polonica ()

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Chase Brownstein

@ChaseBrownstein

3 years

3. I also describe the partial skeleton of an adult hadrosaurid from New Jersey, which was found right next to the skull bones of baby dinosaurs-the first from the northeastern US!

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Chase Brownstein

@ChaseBrownstein

6 years

Bits and pieces of the jaws of Deinonychus @yalepeabody for #FossilFriday

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Chase Brownstein

@ChaseBrownstein

2 years

I love talking about Crypto(lacerta hassiaca from the Late Eocene of Germany)

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Chase Brownstein

@ChaseBrownstein

2 years

imagine being Dartmouth college and giving these away #FossilFriday

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Chase Brownstein

@ChaseBrownstein

6 years

Happy #VelociraptorAwarenessDay ! Here's a closeup of the original skull of Velociraptor described by Henry Osborn @AMNH :

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Chase Brownstein

@ChaseBrownstein

8 months

So excited to see this collaboration out with @paleoTsimoes @michael_s_y_lee @LizardManMeyer @SimonScarpetta & Michael Caldwell. We use phylogenetic hypothesis testing frameworks to revise a putative record of an early crown squamate. Find the paper in @royalsociety open science

Tiago R. Simões

@paleoTsimoes

8 months

Our latest paper just out: NO derived lizards in the Triassic and NO major revision of divergence times for crown squamates using molecular and morphological relaxed clocks. With @ChaseBrownstein @michael_s_y_lee @LizardManMeyer et al.

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Chase Brownstein

@ChaseBrownstein

1 year

It's insane this hasn't been flooding social media-the biggest known Gecko ever is known from a single giant specimen found in a museum drawer in France, it's probably extinct, and molecular phylogenetics had to be used to figure out where it probably comes from!

Nic Rawlence

@nic_rawlence_nz

1 year

Upping cool new study by Heinicke et al. on extinct giant Delcourt's gecko (). Thought to be from #NZ & inspiration for kawekaweau of Māori legend, no fossils found here. Now #ancientDNA shows this gecko part of #NewCaledonia gecko radiation - @smcnz . 1/3

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Chase Brownstein

@ChaseBrownstein

9 months

Very pleased to share my new publication in @Nature disputing a tetrapodomorph ID for Palaeospondylus! Link here: #paleontology #fossils

Palaeospondylus and the early evolution of gnathostomes

Nature - Palaeospondylus and the early evolution of gnathostomes

www.nature.com

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Chase Brownstein

@ChaseBrownstein

5 months

6/14 By using a new dataset of ~1000 UCEs, we resolve deep anglerfish phylogeny, showing that deep-sea open water anglerfishes are secondarily pelagic. They evolved from species that walk along the ocean floor using modified fins and diversified during the Eocene Thermal Maximum!

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Chase Brownstein

@ChaseBrownstein

2 years

8/9 A combination of phylogenetics and high-resolution computed tomography reveals the presence of a second species, Amia ocellicauda, that speciated from A. calva during the Plio-Pleistocene-recent speciation in a living fossil! (below, A ocellicauda)

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Chase Brownstein

@ChaseBrownstein

3 years

5. America also implies that the fauna of eastern North America, which was isolated for ~30 million years in the Late Cretaceous, had distinctive components. You can find the paper here:

Dinosaurs from the Santonian–Campanian Atlantic coastline substantiate phylogenetic signatures of...

During the Cretaceous, diversifications and turnovers affected terrestrial vertebrates experiencing the effects of global geographical change. However, the poor fossil record from the early Late...

royalsocietypublishing.org

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Chase Brownstein

@ChaseBrownstein

2 years

#FossilFriday the gigantic crocodyliform Sarcosuchus. This is really quite an incredible specimen @Le_Museum

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Chase Brownstein

@ChaseBrownstein

5 years

Pleased to share my newest paper has just been published in @SciReports . I reevaluate the bizarre dinosaur Halszkaraptor and show it might not have been semiaquatic after all. Find it here:

Halszkaraptor escuilliei and the evolution of the paravian bauplan

Scientific Reports - Halszkaraptor escuilliei and the evolution of the paravian bauplan

www.nature.com

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Chase Brownstein

@ChaseBrownstein

4 years

His deep, far-reaching contributions to paleontology and evolutionary biology will be remembered. Rest in peace to a scientific giant.

Jordan Mallon

@Jordan_Mallon

4 years

It's with a heavy heart that I pass along news of the passing of our friend and colleague, Dr. Dale Alan Russell, on December 21, 2019. He was 82.

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Chase Brownstein

@ChaseBrownstein

6 years

Here's another for #FossilFriday , the exceptionally preserved skull of @SUEtheTrex at the @FieldMuseum a few years ago showing several pathologies along the mandible.

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Chase Brownstein

@ChaseBrownstein

4 years

Some good news to share-SVP abstract accepted! Looking forward to presenting on eastern North American dinosaur evolution this October! (Photo: the holotype tibia of "Dryptosaurus macropus")

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Chase Brownstein

@ChaseBrownstein

3 years

This giant jaw of Rhizodus @yalepeabody is really impressive! This belonged to a 20+ foot fish close to the common ancestor of all four-limbed vertebrates

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Chase Brownstein

@ChaseBrownstein

3 years

4. These fossils tell us a ton about what dinosaurs were living in North America during a really poorly sampled period in the history of the continent (the Santonian-Campanian). The discovery that Dryptosauridae might include several species from eastern North....

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Chase Brownstein

@ChaseBrownstein

6 years

For #FossilFriday , here's a cast of the skull of Dilophosaurus @AMNH

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Chase Brownstein

@ChaseBrownstein

7 months

This is so freaking cool

Molecular evidence of anteroposterior patterning in adult echinoderms

Nature - RNA tomography and in situ hybridization in echinoderms suggest a new ambulacral-anterior model to relate echinoderm pentaradial symmetry to the ancestral bilateral symmetry.

www.nature.com

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Chase Brownstein

@ChaseBrownstein

3 years

@ChelseaParlett

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