LightNews
jvelezjuarbe.bsky.social
@jvelezjuarbe.bsky.social
150 followers 140 following 25 posts
Associate Curator at NHMLA. Vertebrate paleontologist with an interest in marine mammals and Caribbean vertebrates. Boricua🇵🇷 The Caribbean & Eastern Pacific are my playground! Views are my own.
Posts Media Videos Starter Packs
Pinned
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · Apr 30
Our new paper, published today in @royalsociety.org Proceedings B, documents the presence of #sebecids in the #GreaterAntilles from the early #Oligocene through the early #Pliocene. Sebecids were apex-predator crocodylomorphs adapted to life on land.
#CaribbeanPaleobiology 1/11
A sebecid preys on its prey, a megalocnid sloth, during the Early Pliocene of Hispaniola.
1 8 30
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
These differences may be due to variations in seafloor productivity, and/or physiological differences between #desmostylians, #sirenians and #sloths.
To learn more make sure to check out our paper and its many figures: peerj.com/articles/198...
6/6
#FossilFriday
Aquatic sloths (Thalassocnus) from the Miocene of Chile and the evolution of marine mammal herbivory in the Pacific Ocean
The evolution of marine mammals in South America includes unique and extinct lineages found nowhere else in the world, such as the walrus-convergent whale Odobenocetops and multiple aquatic sloth spec...
peerj.com
3 7
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
Besides describing this amazing material we also compared ancient marine mammal herbivore communities across the Pacific Ocean. One of the things we noticed is that the South Pacific communities were chronostratigraphically younger, but also with smaller body sizes & less diverse.
5/6
#FossilFriday
1 3 5
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
After a thorough morphological assessment we concluded that the morphology of the NBC specimens is closest to #Thalassocnus natans, otherwise known from the late #Miocene of #Peru. But we did noticed some differences that may hint at greater variation, or a different species!
4/6
#FossilFriday
1 3 5
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
The specimens we describe come from the Late #Miocene Bahia Inglesa Formation in the Atacama Region. The fossils, all from the Norte Bahía Caldera (NBC) locality, include associated cranial & postcranial elements of one individual, plus additional material representing others.


3/6
#FossilFriday
1 3 5
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
While fossils of #Thalassocnus are best known from the Pisco Formation in Peru, they've been previously found in Chile too. This includes a site we previously worked on, #CerroBallena! And although mainly known from marine deposits, there is at least one continental record!
2/6
#FossilFriday
1 3 5
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · 9d
My newest publication is out in @peerj.bsky.social! In this collaboration with Ana Valenzuela, Nick Pyenson & Mario Suarez we describe the most complete skeleton of the #AquaticSloth - #Thalassocnus - from #Chile!
Artwork by @alexboersma-art.bsky.social
1/6
#FossilFriday
peerj.com/articles/198...
1 19 62
Reposted
kaycebell.bsky.social
Kayce Bell @kaycebell.bsky.social · 19d
Hi! We need lice for our diversity and adaptation project. Specifically, we need lice from zebras, camelids (camels, llamas, alpacas, vicuñas, guanacos) & aardvarks. If you or someone you know might have lice, I'm happy to discuss our inclusive collaboration plans!
sites.google.com/nhm.org/anop...
Mammals & Lice
We are interested in understanding what drives host-parasite relationships. We are using the Anoplura (sucking lice) parasite and mammalian host system to generate a comprehensive sucking louse phylog...
sites.google.com
1 57 65
Reposted
tarpits.org
La Brea Tar Pits & Museum @tarpits.org · 25d
🍖 Hungry for History? Fossils from the #TarPits reveal the diets of saber-toothed cats, dire wolves, and more—served straight from asphalt.

Take a bite into prehistory: bit.ly/TarPitsPD
Fossilized Bison teeth Fossilized Bison teeth Fossilized Camel teeth Fossilized Horse teeth
3 18
Reposted
val-fisch.bsky.social
Prof. Valentin Fischer @val-fisch.bsky.social · 25d
Are you tired of people constantly overestimating body size of marine reptiles? No longer!

We provide equations to estimate body size in ichthyosaurians, mosasaurids, and thalattosuchians.

1/4
2 25 49
Reposted
arctomet.bsky.social
Thomas R. Holtz, Jr. @arctomet.bsky.social · 28d
A.D. Gentry et al. (2025)

A new leatherback marine turtle from the lower Oligocene of North America and a phylogenetic nomenclature for Dermochelyidae

Palaeodiversity 18(1): 127-149 (2025)

doi: doi.org/10.18476/pal...

bioone.org/journals/Pal...
A new leatherback marine turtle from the lower Oligocene of North America and a phylogenetic nomenclature for Dermochelyidae
The modern leatherback sea turtle Dermochelys coriacea possesses a unique, flexible mosaic carapace adapted for deep diving. The evolutionary origins of this structure remain poorly understood because...
doi.org
8 29
Reposted
friel.bsky.social
John P. Friel, Ph.D. @friel.bsky.social · Sep 12
A new fossil of the Leatherback Turtle from Alabama just dropped! #FossilFriday

bioone.org/journals/Pal...
Family Fishing Trip Leads to “One-in-a-Million” Fossil Discovery - Poarch Creek Indians
A family of four recently discovered the fossilized shell of a 32-million-year-old leatherback sea turtle while fishing along a river in south Alabama. The new species, Ueloca colemanorum was named by...
pci-nsn.gov
14 41
Reposted
nhm.org
Natural History Museum of Los Angeles County @nhm.org · Sep 11
To celebrate a momentous 10 Years of #DinoFest, we’re looking back at a decade of discoveries from the Mesozoic—the period from about 252 to 66 million years ago, when dinosaurs evolved and then came to rule the planet: go.nhm.org/dinofest10

🦖 Will you be joining us this Sunday, September 14?
Reconstruction of Navaornis hestiae in its 80 million-year-old environment Copyright owned by Julia d’Oliveira. Credit: J. d’Oliveira. Email: julia_d.oliveira@hotmail.com The giant ichthyosaur Cymbospondylus youngorum Illustration by Stephanie Abramowicz
12 60
Reposted
tarpits.org
La Brea Tar Pits & Museum @tarpits.org · Sep 2
🐪 Think being stuck in L.A. traffic's a drag? Try getting stuck in its 𝘵𝘢𝘳. Meet 𝘊𝘢𝘮𝘦𝘭𝘰𝘱𝘴 𝘩𝘦𝘴𝘵𝘦𝘳𝘯𝘶𝘴, the Ice Age camel that once roamed North America: bit.ly/AncientCamelLA
Camelops hesternus fossil on display at the La Brea Tar Pits. An illustration of the large-headed llama Hemiauchenia. A Camelops skeleton. An illustration of Camelops hesternus, an extinct North American camel.
1 10 32
Reposted
tarpits.org
La Brea Tar Pits & Museum @tarpits.org · Jul 18
🐾 Are you a saber-toothed cat person, or do you prefer to chill with giant sloths? Pick Your Summer and learn all about these polar opposite Ice Age mammals during your next trip to the #TarPits: go.nhm.org/tpsummer
While we don’t know if there were ever such fetching coats as these, carnivores like tigers and leopards roaming forested habitats today do sport spotted, vertically striped, and horizontally striped fur as camouflage.
1 27
Reposted
tarpits.org
La Brea Tar Pits & Museum @tarpits.org · Jun 26
🦴 𝘼𝙧𝙚 #direwolves back? Dr. Emily Lindsey, Associate Curator and Excavation Site Director at the #TarPits, shares some insight about the Ice Age Angeleno that's making headlines.

youtu.be/v9d1Yu3OZBw
Are Dire Wolves Back? with Dr. Emily Lindsey
YouTube video by La Brea Tar Pits and Museum
youtu.be
1 5 21
Reposted
tarpits.org
La Brea Tar Pits & Museum @tarpits.org · Jun 24
🦣 Meet the #TarPits' resident mammoth, Zed!

Catch a glimpse of the most complete Columbian mammoth discovered in the heart of LA, only at La Brea Tar Pits!
4 49
Reposted
nhm.org
Natural History Museum of Los Angeles County @nhm.org · Jun 18
From the Press Room | New Species of Armored, Monstersaur Lizard that Lived Alongside Dinosaurs Identified by #NHMLA Paleontologists!

Discovery of 𝘉𝘰𝘭𝘨 𝘢𝘮𝘰𝘯𝘥𝘰𝘭 reveals the complex evolutionary history of giant Gila Monster relatives: go.nhm.org/bolg-pr

📷 Cullen Townsend
Artistic reconstruction of Bolg amondol, depicted raiding an oviraptorosaur dinosaur nest amidst the lush Kaiparowits Formation habitat. Art by Cullen Townsend.
1 6 39
Reposted
nhm.org
Natural History Museum of Los Angeles County @nhm.org · Jun 11
Museums can be places of respite, peace, and recreation, and we strive to make the Natural History Museum and La Brea Tar Pits welcoming for all. We’re with you, L.A.
Dulled image of a butterfly with text "Los Angeles is our home. We're here for our community. WE LOVE L.A." with the Natural History Museum and La Brea Tar Pits logos.
2 13 56
Reposted
val-fisch.bsky.social
Prof. Valentin Fischer @val-fisch.bsky.social · Jun 7
🎉New lab paper lead by @just-fre.bsky.social based on his master thesis work! Francesco and his colleagues describe new allodaposuchid material from the latest Cretaceous of Spain (as well as the importance of postcranial anatomy for croc phylogenies 😉).

www.sciencedirect.com/science/arti...
A NEW ARMORED CROCODYLIFORM FROM THE UPPER CRETACEOUS OF CATALONIA (SPAIN): NEW INSIGHT INTO THE EVOLUTION OF THE EUSUCHIAN POSTCRANIAL AND DERMAL SKELETON
The origin and early radiation of Crocodylia have shifted attention to the Upper Cretaceous of Europe, where numerous new taxa have recently been disc…
www.sciencedirect.com
2 3
Reposted
planet-of-fishes.bsky.social
William B. Ludt, PhD @planet-of-fishes.bsky.social · May 3
Coelacanths having a great week! First a new live sighting of the Indonesian species, and now this fantastic work on their musculature by Aléssio Datovo and the late Dave Johnson
prosanta.bsky.social
Prosanta Chakrabarty @prosanta.bsky.social · May 3
Coelacanths illuminate deep-time evolution of cranial musculature in jawed vertebrates.

By Aléssio Datovo & G. David Johnson Sci. Adv. 2025

www.science.org/doi/10.1126/...
Coelacanths illuminate deep-time evolution of cranial musculature in jawed vertebrates
Revised coelacanth cranial muscle anatomy reveals previously unknown evolutionary innovations and redefines gnathostome muscle evolution.
www.science.org
4 15
Reposted
nhm.org
Natural History Museum of Los Angeles County @nhm.org · Apr 29
NEWLY PUBLISHED » Dr. Jorge Velez-Juarbe (Associate Curator, Marine Mammals) discovers that sebicids, ancient land-dwelling crocodile-like beasts, reigned over the West Indies as apex predators after vanishing from South America: bit.ly/AncientCrocs
A sebecid and its prey, a megalocnid ground sloth, overlook a coastal pond in the Dominican Republic around 5.8 million years ago. Artwork by Machuky Paleoart.
22 59
Reposted
floridamuseum.bsky.social
Florida Museum of Natural History @floridamuseum.bsky.social · Apr 30
A fossil tooth and two vertebrae unearthed in the Dominican Republic have paleontologists rethinking sebecids, giant croclike terrestrial predators, and their story in the Caribbean.

Story:
www.floridamuseum.ufl.edu/science/gian...

Study: doi.org/10.1098/rspb...
an illustration shows a creature like a large lizard or crocodile with a fuzzy mammal animal at its feet on a grassy lip of land overlooking a small lagoon or pond with layers of rolling hills covered in tropical trees disappearing into a pale pink sunset mist
3 9
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · Apr 30
And that's a wrap! Our paper is #OpenAccess and the specimens were CT-scanned with data available through www.morphosource.org
Big shoutout to @machukypaleoart.bsky.social for the awesome artwork!
Stay tuned for more Caribbean extinct vertebrates in the future!
#CaribbeanPaleobiology
11/11
MorphoSource
www.morphosource.org
3
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · Apr 30
Insular sebecids went extinct several million years after their South American counterparts, marking the end of Notosuchia — a long-lived clade of terrestrial crocodyliforms. Their extinction likely reshaped predator-prey dynamics in the Antillean islands and on the South American continent.
10/11
Maps of South America and the Caribbean region during the (a) Palaeogene, (b) Neogene and (c) late Quaternary show the generalized distribution of Sebecidae in circles. The silhouettes correspond to the terrestrial apex predator groups present in the region during each period, with native South American predators (Sebecidae, Madtsoiidae, Phorusrhacidae, Sparassodonta) in blue, late Cenozoic invasive predators (Canidae, Felidae, Ursidae) in red and endemic secondary terrestrial predators in the West Indies (Strigiformes, Accipitridae, Crocodylus) in green.
1 2
jvelezjuarbe.bsky.social
jvelezjuarbe.bsky.social @jvelezjuarbe.bsky.social · Apr 30
The presence of sebecids alongside side-necked turtles, gharials, caviomorph rodents, megalocnid sloths and platyrrhine primates strongly suggests that between 29-4.6 million years ago Antillean terrestrial ecosystems closely resembled those in #SouthAmerica.
9/11
1 2