Lightnews — Scholar-powered news

Reposted by Bruno do Rosario Petrucci

Casey Dunn @caseywdunn.bsky.social · Aug 28

I hope to take a PhD student in 2026 to study siphonophores. Please reach out if you are interested in applying this fall. For examples of recent lab projects see www.sciencedirect.com/science/arti... and academic.oup.com/gbe/article/...

1 46 54

Reposted by Bruno do Rosario Petrucci

Joe Spring @joespring.bsky.social · Aug 4

Once upon a time, large bone-crushing dogs roamed across our continent. @restingdinoface.bsky.social takes a colorful look back at the lives of the successful carnivores. www.smithsonianmag.com/science-natu...

What Happened to the Bone-Crushing Dogs That Once Hunted Across North America?

Before going extinct roughly two million years ago, canids known as borophagines took down and consumed much larger prey

www.smithsonianmag.com

2 9 35

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jul 30

Going from reading almost exclusively simulation studies and theory papers to almost exclusively canid systematics/fossil description papers has been an interesting experience!

Anyway look at this cool paper about Plio-Pleistocene European foxes!
www.sciencedirect.com/science/arti...

Unraveling the fossil record of foxes: An updated review on the Plio-Pleistocene Vulpes spp. from Europe

Fossil foxes, genus Vulpes, are known since the Late Miocene of North America and the Old World but their record is utterly scarce, fragmentary, and r…

www.sciencedirect.com

2

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jul 29

They're listening to my private conversations somehow, I'm certain of it.

Holy crap I'm excited 🤩

Claude ✡️🦖🦕 @cascoclauda.bsky.social · Jul 29

AMAZING NEWS!
apple tv has just announced a NEW pleistocene-focused series of #prehistoricplanet! streaming on november 26th

a pair of machairodontines laying in a snow-covered field; they look quite robust, but i'm unsure if they are smilodon or a different taxon like homotherium

a baby giant ground sloth (unsure of taxon) clings to its mother's back as the mother climbs a cliff-face

1

Reposted by Bruno do Rosario Petrucci

April Wright @wrightam.bsky.social · Jul 15

Updated preprint! Thanks to suggestions from reviewers, we have some new insights on using continuous traits in phylogenetic estimation.

And a lot more about dicynodont taxonomy. Seriously, google dicynodonts and tell me you don't want to know what's happening there

www.biorxiv.org/content/10.1...

Incorporating continuous characters in joint estimation of dicynodont phylogeny

Continuous characters have received comparatively little attention in Bayesian phylogenetic estimation. This is predominantly because they cannot be modeled by a standard phylogenetic Q-matrix approac...

www.biorxiv.org

1 13 34

Reposted by Bruno do Rosario Petrucci

Jasmine 🌌🔭 @astrojaz.bsky.social · Jul 4

here are some space fireworks, happy 4th of july 🎆🌌

The brilliant tapestry of young stars flaring to life resemble a glittering fireworks display in this Hubble Space Telescope archival image.

The sparkling centerpiece of this fireworks show is a giant cluster of thousands of stars.

The nebula reveals a landscape of pillars, ridges, and valleys. The pillars, composed of dense gas and thought to be incubators for new stars, are a few light-years tall and point to the central star cluster. Other dense regions surround the pillars, including reddish-brown filaments of gas and dust. The red dots scattered throughout the landscape are a rich population of newly forming stars still wrapped in their gas-and-dust cocoons. The brilliant blue stars seen throughout the image are mostly foreground stars.

The red colors in the nebulosity represent hydrogen; the bluish-green hues are predominantly oxygen.

Caption credit: NASA

$A globular cluster that looks like a very dense, ball-shaped collection of many shining stars in colors of white, yellow-orange, and blue. Some stars appear a bit larger and brighter than others, with the brightest having faint cross-shaped diffraction spikes. The cluster’s stars are scattered mostly uniformly, with their density increasing toward the cluster’s core where they merge into a strong, bright-white glow.$

This image of Cassiopeia A resembles a disk of electric light with red clouds, glowing white streaks, red and orange flames, and an area near the center of the remnant resembling a somewhat circular region of green lightning. X-rays from Chandra are blue and reveal hot gas, mostly from supernova debris from the destroyed star, and include elements like silicon and iron. X-rays are also present as thin arcs in the outer regions of the remnant. Infrared data from Webb is red, green, and blue. Webb highlights infrared emission from dust that is warmed up because it is embedded in the hot gas seen by Chandra, and from much cooler supernova debris. Hubble data shows a multitude of stars that permeate the field of view.

A prominent, eight-pointed star shines in bright white at the center of this image. A clumpy cloud of material surrounds this central star, with more material above and below than on the sides, in some places allowing background stars to peek through. The cloud material is a dark yellow closer to the star, and turns a pinkish purple at its outer edges. Combined together, the central star and its cloud resemble the delicate petals of a cherry blossom. The black background features many smaller white stars scattered throughout.

3 25 150

Reposted by Bruno do Rosario Petrucci

Miguel Bastos Araújo, PhD @miguelbaraujo.bsky.social · Jul 4

We’re hiring! Join us at maraujo lab as a #PhD candidate to model species abundances using cutting-edge ecological and statistical tools. Based at @mncn-csic.bsky.social @mncn-bgcg.bsky.social and @utrechtuniversity.bsky.social.
🔗 www.maraujolab.eu/2025/07/04/p...
#SpeciesDistributionModels

PhD candidate in species abundances modelling -

Project Description Understanding species abundance patterns is essential to addressing fundamental questions in macroecology and biogeography, specifically about […]

www.maraujolab.eu

18 25

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jul 3

Having to write an R script to write another script makes me feel like I am in limbo

Reposted by Bruno do Rosario Petrucci

Katie Mack @astrokatie.com · Jun 19

When a chatbot gets something wrong, it’s not because it made an error. It’s because on that roll of the dice, it happened to string together a group of words that, when read by a human, represents something false. But it was working entirely as designed. It was supposed to make a sentence & it did.

62 1.4K 7.1K

Reposted by Bruno do Rosario Petrucci

Katie Mack @astrokatie.com · Jun 19

Chatbots — LLMs — do not know facts and are not designed to be able to accurately answer factual questions. They are designed to find and mimic patterns of words, probabilistically. When they’re “right” it’s because correct things are often written down, so those patterns are frequent. That’s all.

560 8.6K 29K

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 30

It’s great to see researchers exploring the possibilities of learning about current extinction from past extinction patterns. That was my initial idea for my PhD, and I have deviated from that pretty hard since then, but I still hope to get on that wagon later in my career!

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 30

Very cool paper! Glad to see Bluesky helping me find new cool science hot off the press 🍞

Jens-Christian Svenning @jcsvenning.bsky.social · Jun 30

🦣 New paper: Megafauna with large size & flat-footedness + less related to tropical African/Asian fauna were more likely to go extinct in recent prehistory; consistent w direct hunting including pre-sapiens human filtering👣👉 doi.org/10.1111/geb....
#Megafauna #Extinction #TraitEcology #Palaeoecology

Phylogenetic Evidence Supports the Effect of Traits on Late‐Quaternary Megafauna Extinction in the Context of Human Activity

Aim The late-Quaternary extinctions, which affected primarily large mammals, are strongly connected to the migration of modern humans out of sub-Saharan Africa and tropical Asia (the Palaeotropics),...

doi.org

1 1 7

Reposted by Bruno do Rosario Petrucci

𝙱𝙰𝚂𝙰𝙽𝚃𝙰 𝙺𝙷𝙰𝙺𝚄𝚁𝙴𝙻 @basantakhakurel.bsky.social · Jun 27

🆕 Preprint now on bioRxiv!
We introduce a covarion model for phylogenetic inference using discrete morphological data, addressing lineage- and character-specific rate heterogeneity.

www.biorxiv.org/content/10.1...

#phylogenetics #morphology #covarion #evolution

A covarion model for phylogenetic estimation using discrete morphological datasets

The rate of evolution of a single morphological character is not homogeneous across the phylogeny and this rate heterogeneity varies between morphological characters. However, traditional models of mo...

www.biorxiv.org

7 12

Reposted by Bruno do Rosario Petrucci

Paul D. Taylor @nhmbryozoa.bsky.social · Jun 30

#MolluscMonday Ordovician orthoconic nautiloid in a paving stone at Hampton Court Palace. The section intersects the siphuncular tube on the right hand-side just below the living chamber.

2 10 45

Reposted by Bruno do Rosario Petrucci

Anthony (Tony) J. Martin @ichnologist.bsky.social · May 22

Excellent analysis & commentary by @johnhawks.net on 2024 study of 1.5 mya fossil hominin footprints in Kenya showing 2 different species of humans (Homo erectus & Paranthropus boisei) walking in the same direction, & possibly separated by only a few hours. Ichnology FTW! 🧪🐾🪨

John Hawks @johnhawks.net · May 22

My look at the most recent science of footprint analysis for ancient human relatives. An extraordinary case from the ancient shores of Lake Turkana, revealing trackways by two species, Homo erectus and Paranthropus boisei, made within a short time.

www.johnhawks.net/p/when-homin...

Footprints of two hominin species hours apart on the same shoreline

A new study by Kevin Hatala and coworkers finds that Homo erectus and Paranthropus boisei walked on the same shores within hours of each other.

www.johnhawks.net

1 13 26

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 30

For those who followed me without knowing me (thank you and nice to meet you!), it’s very important for you to know that I am unhealthily obsessed with horseshoe crabs.

I don’t even study them at all, and they’ve just been my favorite animal since I found out they existed. They’re the coolest!

Get To Know Nature @gettoknownature.bsky.social · Jun 29

Just a horseshoe crab doing its thing. Its thing is heading back to the water after a volunteer rescued it from being stuck on its back and left behind by the tide. 😅 I love the scraping noise they make as they move along the sand.

#invertebrates 🦀 🌿

2

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

Thank you! Would love to talk more about it any time!!

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

13/13 And that's that! Here's the full talk. I'll record a longer, higher quality version later, and post it here with a more detailed rundown. And of course I'll let you all know when the paper is published! Lots I still want to do for this project.

Stay tuned!

youtu.be/aS31GnXh3ec

Inferring a complete phylogenetic tree of Canidae under the SRFBD process - Evolution 2025

YouTube video by Bruno do Rosario Petrucci

youtu.be

1 2

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

12/13 I'd love to sit here and say "yes, this easier model provides reasonable trees, keep using it!", but SRFBD is the only way to truly accommodate for this data. I think it's worth the implementation challenge, and that it is the future of fossil phylogenetics. And look at this beautiful tree!

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

11/13 We need simulations to be sure of which model is more accurate, but the fact that we can identify specific model violations and connect them to biases in our estimates is concerning. We tried a different workaround than usual for FBD specimen, and unfortunately it doesn't seem to have helped!

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

10/13 This, together with the fact that we are not using all the samples for each of our species, might be related to why we estimate lower fossil sampling rates and higher speciation rates with FBD specimen. This leads to younger estimates of divergence times.

1 2

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

9/13 While the first specimen of Epicyon haydeni is correctly placed as a sampled ancestor of the last, the opposite is true for Epicyon saevus. They're tips, and at the same time! Compare that to the same node in our SRFBD tree and you can see the issue.

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

8/13 So the model is telling us Archaeocyon is a canine! Very interesting, and something to look into.

We do need to talk about where the FBDS workaround we did (using both the youngest and oldest specimens for a given species) fails. In the MCC tree using both specimens, we see some of this:

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

7/13 A cool example of where they agree: both models estimate a really low posterior probability (<0.005) of the monophyly of Borophaginae. The monophyly of Borophaginae minus Archaeocyon (the first-diverging genus), however, is pretty likely. So is the monophyly of (Archaeocyon, Caninae).

1

Bruno do Rosario Petrucci @brpetrucci.bsky.social · Jun 27

6/13 There's no good way to summarize budding trees currently, so to compare the trees I made MCC trees from a modified posterior sample, removing the first specimen of each tree. So this is a tree the way you're used to: one tip per species. You can see they're pretty similar (RF-distance: 0.19)

1