Triassic paleoecology studies – Science

New Toothless, Bizarre Bipedal Crocodile Relative from the Triassic Unearthed

Gavin Prescott — Tue, 26 May 2026 13:09:32 +0000

In the kaleidoscopic dawn of the Triassic period, the natural world was undergoing one of its most fascinating evolutionary experiments. Modern animals, which we often take for granted, were just beginning to develop a staggering variety of forms and ecological niches. Amid this surge of diversification, bizarre and unexpected creatures emerged, challenging our understanding of evolutionary pathways and convergent evolution. One such remarkable discovery is the recently described Labrujasuchus expectatus, a shuvosaurid archosaur from the Late Triassic Hayden Quarry in New Mexico, whose peculiar anatomy looks like an evolutionary riddle come to life.

The newly unveiled Labrujasuchus expectatus disrupts traditional notions of crocodilian evolution. Emerging from the lineage that gave rise to modern crocodiles—known for their quadrupedal stance and formidable teeth—Labrujasuchus defied expectations by evolving a bipedal locomotion, tiny arms, and most strikingly, a toothless beak. Its morphology startlingly resembles ornithomimosaurs, those swift, bipedal theropod dinosaurs often compared to modern ostriches, yet it belongs unmistakably to a different archosaur clade. This astounding case of convergent evolution illustrates how environmental pressures can shape drastically different evolutionary branches to arrive at similar solutions.

The significance of Labrujasuchus lies not only in its physical form but also in its ecological implications. The Late Triassic was a crucible of evolutionary innovation, where many modern animal strategies first emerged. Archosaurs were diversifying into a myriad of forms, from the gliding pterosaurs, descendants of bipedal cousins called lagerpetids, to the arboreal oddity Drepanosaurus with its grasping claws and prehensile tail. The presence of a bipedal crocodilian relative further underscores the adaptive experimentation rampant during this period.

Dr. Alan Turner, the lead author of the study published in the Journal of Vertebrate Paleontology, emphasizes the evolutionary uniqueness of Labrujasuchus. “The transition to bipedalism in crocodile relatives is exceptionally rare, making Labrujasuchus a fascinating subject for studying locomotor evolution. While bipedality is well-documented in dinosaurs and birds, uncovering a crocodile-line archosaur that adopted this mode of movement challenges our preconceived narratives,” he explains. This convergent evolutionary path highlights the plasticity of archosaur morphologies in response to ecological pressures.

This discovery fills an essential gap in the fossil record of shuvosaurs, a family of archosaurs with enigmatic body plans that have only recently begun to be understood. Prior to this find, two shuvosaur species from the same geological region delineated a broad evolutionary bracket. Labrujasuchus now elegantly occupies the intermediate phase, bridging temporal and morphological gaps in this intriguing lineage. The precise timing and morphology of this shuvosaur highlight the meticulous unfolding of archosaur diversity during the Triassic.

The species’ nomenclature carries both scientific and folkloric significance. Derived from “Ranchos de los Brujos”—Spanish for “Ranch of the Witches”—the genus name Labrujasuchus pays homage to the Ranch of the Witches site, also known as Ghost Ranch, where the fossil was discovered. The species name, expectatus, meaning “expected,” creatively references how paleontologists anticipated an intermediate shuvosaur species would eventually be found, validating predictive models based on earlier fossil records. This thoughtful naming encapsulates the intersection of scientific rigor and local cultural history.

Ghost Ranch itself holds a special place in paleontology, renowned not only for its dramatic red badlands immortalized by artist Georgia O’Keeffe but also as a treasure trove of Triassic fossils. This multi-quarry site has contributed immensely to our knowledge of Late Triassic ecosystems. The ongoing excavation project, co-led by co-author Dr. Nate Smith of the Natural History Museum of Los Angeles County (NHMLAC), continues to unearth a diverse cast of prehistoric creatures, enriching our understanding of this enigmatic era.

The broader implications of studying Labrujasuchus extend far beyond taxonomy. The Triassic period’s evolutionary experiments provide vital context for modern biodiversity crises. Many creatures from this epoch developed global survival strategies, some of which still underpin ecosystems today. By examining these ancient life forms, scientists can glean insight into resilience, adaptation, and extinction—lessons profoundly relevant as contemporary species face accelerating environmental changes.

Modern crocodilians are often stereotyped as relics from a bygone era, seemingly unchanged for millions of years. However, Labrujasuchus reminds us that their evolutionary history is far more complex and dynamic. The physiology and anatomy of these prehistoric relatives underscore evolutionary plasticity and innovation rather than static stasis. As paleontologists continue to unravel these threads, the narrative of crocodilian evolution gains nuance and depth.

The Natural History Museum of Los Angeles County plays a pivotal role in this research frontier. Their Dinosaur Institute curates an extensive collection of Mesozoic tetrapod fossils, encompassing not only dinosaurs but a wide array of contemporaneous vertebrates including early mammals, amphibians, and other archosaurs like Labrujasuchus. This resource allows scientists and students alike to investigate evolutionary patterns and functional morphologies with unprecedented detail.

The discovery of Labrujasuchus imparts a profound message about the Triassic world: it was an era of unpredictable evolutionary experimentation, where lineages diverged and converged in extraordinary ways. The peculiar yet elegant adaptations of this shuvosaur exemplify the dynamic interplay of environment, physiology, and ecology that shaped modern vertebrate diversity. It is a testament to the enduring power of fossils to surprise us and rewrite the textbooks.

As research continues, the combination of field excavation, detailed anatomical analysis, and comparative phylogenetics will likely illuminate more aspects of shuvosaur evolution. Each new find stitches together the complex tapestry of life’s grandeur during the Mesozoic. Labrujasuchus expectatus stands as a remarkable milestone in this journey, offering a window into a world where crocodile ancestors roamed on two legs, challenging our assumptions and broadening our scientific horizons.

Subject of Research: Animals
Article Title: A NEW SHUVOSAURID (ARCHOSAURIA, POPOSAUROIDEA) FROM THE LATE TRIASSIC (NORIAN) HAYDEN QUARRY OF NEW MEXICO, U.S.A.
News Publication Date: 26-May-2026
Web References: http://dx.doi.org/10.1080/02724634.2026.2618182
Image Credits: Credit to Jorge Gonzalez

Keywords: Triassic, Labrujasuchus expectatus, Shuvosauridae, Archosauria, Convergent Evolution, Bipedal Crocodile Relatives, Hayden Quarry, Natural History Museum of Los Angeles County, Dinosaur Institute, Paleoecology, Fossil Discovery, Evolutionary Biology

A new species of extinct crocodile relative rewrites life on the Triassic coastline

Drew Townsend — Thu, 11 Jul 2024 05:24:47 +0000

Los Angeles, CA (July 10, 2024)— The surprising discovery of a new species of extinct crocodile relative from the Triassic Favret Formation of Nevada, USA, rewrites the story of life along the coasts during the first act of the Age of Dinosaurs. Described in a study published in Biology Letters, the new species Benggwigwishingasuchus eremicarminis reveals that while giant ichthyosaurs ruled the oceans, the ancient crocodile kin known as pseudosuchian archosaurs ruled the shores across the Middle Triassic globe between 247.2 and 237 million years ago.

Credit: artwork by Jorge Gonzalez

“This exciting new species demonstrates that pseudosuchians were occupying coastal habitats on a global basis during the Middle Triassic,” said Dr. Nate Smith, lead author of the paper, and Gretchen Augustyn Director and Curator of the Dinosaur Institute at the Natural History Museum of Los Angeles County.

Capturing fossil life from the eastern Panthalassan Ocean of the Triassic, the locality that includes the Favret Formation is known for fossils of sea-going creatures like ammonites along with marine reptiles like the giant ichthyosaur C. youngorum—finding the newly described B. eremicarminis came as a bit of a shock.

“Our first reaction was: What the hell is this?” said co-author Dr. Nicole Klein of the University of Bonn. “We were expecting to find things like marine reptiles. We couldn’t understand how a terrestrial animal could end up so far out in the sea among the ichthyosaurs and ammonites. It wasn’t until seeing the nearly completely prepared specimen in person that I was convinced it really was a terrestrial animal.”

Pseudosuchian archosaurs have been unearthed in fossil beds from the shores of the ancient Tethys Ocean, but this is the first coastal representative from the Panthalassan Ocean and western hemisphere, revealing that these crocodile relatives were present in coastal environments worldwide during the Middle Triassic. Interestingly, these coastal species aren’t all from the same evolutionary group, suggesting that pseudosuchians (and archosauriforms more broadly) were independently adapting to life along the shores.

“Essentially, it looks like you had a bunch of very different archosauriform groups deciding to dip their toes in the water during the Middle Triassic. What’s interesting, is that it doesn’t look like many of these ‘independent experiments’ led to broader radiations of semi-aquatic groups,” said Smith.

During the Triassic, archosaurs, “the ruling reptiles,” arose and split into two groups with two surviving representatives: birds, the descendants of dinosaurs, and crocodilians (alligators, crocodiles, and gharials), the descendants of pseudosuchian archosaurs like B. eremicarminis. While today’s crocodilians are similar enough to be mistaken for one another by most people, their ancient relatives varied wildly in size and lifestyle. The evolutionary relationships of B. eremicarminis and its relatives suggest that pseudosuchians achieved great diversity very quickly following the End-Permian mass extinction—the extent of which is waiting to be discovered in the fossil record.

“A growing number of recent discoveries of Middle Triassic pseudosuchians are hinting that an underappreciated amount of morphological and ecological diversity and experimentation was happening early in the group’s history. While a lot of the public’s fascination with the Triassic focuses on the origin of dinosaurs, it’s really the pseudosuchians that were doing interesting things at the beginning of the Mesozoic,” Smith said.

The new species underlines the multiplicity of these ancient reptiles during the Triassic, from giants like Mambawakale ruhuhu to smaller animals like the newly described B. eremicarminis, which probably reached around 5–6 feet in length. Exactly how long B. eremicarminis was and how it survived along the coasts remains shrouded in the past. Only a few elements of the individual’s skull were found, and any clues to how it fed and hunted are similarly absent. What’s more clear is that B. eremicarminis likely stuck pretty close to the shore. Its well-preserved limbs are well-developed without any of the signs of aquatic living like flippers or altered bone density.

The research team wanted a name that paid respect to the original human inhabitants of the Augusta Mountains where the specimen was found, and so consulted a member of the Fallon Paiute Shoshone Tribe to decide on an appropriate name.“Benggwi-Gwishinga”, a word that means “catching fish” in Shoshone, was combined with the Greek word for Sobek, the Egyptian crocodile-headed god, to coin the new genus, Benggwigwishingasuchus. The specific epithet eremicarminis translates to “desert song”, honoring two supporters of NHMLAC who have a passion for the paleontology and opera of the Southwest. Thus, the full name is meant to translate roughly as “Fisherman Croc’s Desert Song.”

About the Natural History Museums of Los Angeles County (NHMLAC)
The Natural History Museums of Los Angeles County (NHMLAC) include the Natural History Museum in Exposition Park, La Brea Tar Pits in Hancock Park, and the William S. Hart Museum in Newhall. They operate under the collective vision to inspire wonder, discovery, and responsibility for our natural and cultural worlds. The museums hold one of the world’s most extensive and valuable collections of natural and cultural history—more than 35 million objects. Using these collections for groundbreaking scientific and historical research, the museums also incorporate them into on- and offsite nature and culture exploration in L.A. neighborhoods, and a slate of community science programs—creating indoor-outdoor visitor experiences that explore the past, present, and future. Visit NHMLAC.ORG for adventure, education, and entertainment opportunities.

About the Dinosaur Institute
The Dinosaur Institute (DI) houses NHMLAC’s collection of Mesozoic tetrapods (four-limbed vertebrates), dating from 250 million to 65.5 million years ago. This collection includes fossils of dinosaurs spanning the Mesozoic Era, as well as fossils of other tetrapods that lived alongside the dinosaurs, such as flying and marine reptiles, crocodiles, turtles, amphibians, and early mammals. The DI maintains an active paleontological training program, supporting undergraduates, PhD students, and Postdoctoral fellows.

Journal

Biology Letters

DOI

10.1098/rsbl.2024.0136

Method of Research

Observational study

Subject of Research

Animals

Article Title

A new pseudosuchian from the Favret Formation of Nevada reveals that archosauriforms occupied coastal regions globally during the Middle Triassic

Article Publication Date

10-Jul-2024