During the Triassic Period, many of the major animal groups we know today were only beginning to evolve. The world was filled with unusual creatures experimenting with body shapes and lifestyles that often resemble modern animals or later dinosaurs. One newly identified species, Labrujasuchus expectatus, is a striking example.
Described in the Journal of Vertebrate Paleontology, Labrujasuchus had an appearance that would seem more at home among ostrich-like dinosaurs than crocodile relatives. It walked on two legs, had small forelimbs, and lacked teeth. Instead, its mouth ended in a beak.
What makes this especially surprising is its place on the evolutionary tree. Labrujasuchus belonged to the archosaur lineage that eventually gave rise to crocodiles, animals best known today for their four-legged bodies and tooth-filled jaws. In contrast, this newly described species looked almost nothing like its modern relatives.
As the researchers note, the Triassic was an era full of evolutionary surprises.
A Strange World of Triassic Reptiles
The Triassic landscape was home to a remarkable variety of reptiles with unusual adaptations.
Among them were lagerpetids, small bipedal relatives of dinosaurs whose descendants would eventually evolve into pterosaurs. There was also Drepanosaurus, a tree-dwelling reptile equipped with a large claw resembling that of a tree sloth, along with a smaller claw on its prehensile tail. Another example was Vancleavea, an armored aquatic reptile often compared to a miniature tank.
Into this already strange ecosystem stepped Labrujasuchus expectatus, the newest known member of Shuvosauridae. This small group of ancient crocodile relatives evolved body plans that closely resembled bipedal theropod dinosaurs, despite belonging to a very different branch of the reptile family tree.
“We see a lot of the successful strategies for modern animals and non-avian dinosaurs first arise in the Triassic, and shuvosaurs are a great example of that convergent evolution,” says Dr. Alan Turner, lead author on the paper. “Bipedalism is certainly a unique path for crocodile relatives to take, but it’s a path well-trod by dinosaurs and later birds. It obviously worked for these animals.”
Filling an Evolutionary Gap
Only five shuvosaur species have been identified so far, making the new discovery especially important.
Researchers had previously found shuvosaur fossils from older and younger rock layers in the region, suggesting that additional species likely existed in between. Labrujasuchus expectatus fills that predicted gap, providing an evolutionary link that paleontologists had long expected to uncover.
The species name, expectatus, reflects that idea. Scientists anticipated that an intermediate form would eventually be found, making the discovery both expected and unexpected at the same time.
The genus name also carries local significance. Labrujasuchus combines a reference to “Ranchos de los Brujos,” an old Spanish name for Ghost Ranch meaning Ranch of the Witches, with the Greek word Σοῦχος (suchus), meaning “crocodile.”
“Legend has it, the local rancheros gave the site the name ‘Ranchos de Los Brujos’ to keep folks away from the cattle-rustling operations of the Archuleta brothers,” says Dr. Nate Smith, co-author and Gretchen Augustyn Director & Curator of the NHMLAC Dinosaur Institute. “We wanted to give a nod to that colorful history, and honor the incredible role Ghost Ranch has played in expanding our view of the Triassic. We also wanted to highlight how the fossil record works — finding one shuvosaur from earlier in the Triassic and one from later meant that we paleontologists knew there were probably more from in-between waiting to be discovered and described.”
Ghost Ranch and the Search for Triassic Life
The Triassic can sometimes seem almost alien compared to the modern world. Yet many of the body plans seen in those ancient animals foreshadow features that later appeared in dinosaurs, birds, and other groups. Studying these early evolutionary experiments helps scientists better understand how life developed and adapted over time.
Ghost Ranch in New Mexico remains one of the most important windows into this distant past. The site contains multiple fossil quarries that have been excavated for decades and continues to yield exceptionally preserved specimens from the Late Triassic.
“This summer is the 20th anniversary of Nate and his colleagues coming out to do excavations at Ghost Ranch, and we’re so proud to play a central role in making that incredible research possible,” says Joanne Lefrak, Director of Experience and Social Impact at the Ghost Ranch Education and Retreat Center, where teams of paleontologists and volunteers are hosted each summer. “Whether visitors are seeking its iconic landscape and spiritual healing or digging into ancient history, Ghost Ranch is a place like nowhere else on the planet. We’re looking forward to collaborating with Dr. Turner, Dr. Smith, and all their colleagues to continue sharing this extraordinary place for years to come.”
Ghost Ranch, known worldwide through the dramatic paintings of Georgia O’Keeffe, is also home to an ongoing multi-year excavation effort. The project, co-led by Dr. Smith at the NHMLAC Dinosaur Institute, focuses on uncovering Late Triassic animals from the Hayden Quarry and continues to reveal new pieces of one of Earth’s most unusual prehistoric ecosystems.