Anabisetia: Dog-sized Herbivore Dino of Argentina’s Late Cretaceous

Anabisetia: Dog-sized Herbivore Dino of Argentina’s Late Cretaceous

Anabisetia, a name that might not ring as familiar as the mighty T-Rex or the towering Brachiosaurus, still holds its own in the annals of paleontology. Discovered relatively recently, it provides us with intriguing insights into the diverse and complex ecosystems of the Late Cretaceous Period. As we explore this creature’s world, we’ll uncover not just the bones of a long-gone species, but also the stories and secrets they carry.

Anabisetia Key Facts

Key FactDetail
Meaning of nameNamed after Ana Marie Biset
Type SpeciesAnabisetia saldiviai
When it Lived93.5 to 89.3 MYA
PeriodLate Cretaceous
Length6.6 feet
Height2.0 feet
Weight44.0 pounds
MobilityMoved on two legs
First Discovery1985 by Roberto Saldivia
Described by2002 by Rodolfo Coria‭ & ‬Jorge Calvo
Location of first findNeuquen Province, Argentina

Anabisetia Origins, Taxonomy and Timeline

Anabisetia, a name that resonates with a personal touch, was named in honor of Ana Marie Biset, an Argentinian archeologist, for her large contribution to the provincial fossil legistiation. This choice of name reflects a tradition in paleontology where discoverers pay homage through nomenclature, often leading to names that are as unique as the creatures themselves. Its species name, saldiviai, refers to Mr. Roberto Saldivia who found the first remains and was part of the field work team.

Anabisetia was a quite small herbivore which roamed what is today Southern Argentina in the Late Cretaceous Period.

In the grand tapestry of dinosaur classification, Anabisetia finds its place within the Ornithischia, specifically under the Iguanodontia family. This categorization is crucial as it helps us understand its evolutionary relationships and ecological role. Ornithischians, known for their bird-like hips, were predominantly herbivorous and played a significant role in their ecosystems. Anabisetia is phylogenetically close to Talenkauen.

The timeline of Anabisetia is particularly intriguing. It thrived during the Late Cretaceous Period, specifically from the Middle-Late Turonian. This places it in a time frame of approximately 93.5 to 89.3 million years ago, a period marked by significant geological and climatic changes.

Understanding the era in which Anabisetia lived is vital for contextualizing its existence. The Late Cretaceous was a time of diverse and abundant life, both on land and in the seas. It was a period that saw the dominance of dinosaurs and the emergence of new species, making Anabisetia’s existence all the more fascinating.

Discovery & Fossil Evidence

The story of Anabisetia’s discovery begins in 1985, when Roberto Saldivia first stumbled upon this Cretaceous treasure in the Neuquen Province, a region known for its rich fossil deposits. This initial discovery marked the beginning of a journey into understanding this unique dinosaur.

Reconstructed skeleton cast
Kabacchi, CC BY 2.0, via Wikimedia Commons

While Anabisetia may not boast a vast array of fossil finds like some of its more famous counterparts, the quality and preservation of the specimens found are noteworthy. The holotype, MCF-PVPH-74, serves as a crucial piece in unraveling the mysteries of this species. These remains have provided invaluable insights into the physical characteristics and lifestyle of Anabisetia.

The fossil evidence of Anabisetia, though limited, paints a picture of a creature that was well-adapted to its environment. The degree of preservation seen in the fossils suggests that they were quickly covered after death, providing a snapshot of life millions of years ago. This level of preservation is a boon for scientists, allowing for more accurate reconstructions and interpretations.

Anabisetia Size and Description

Anabisetia, a small but remarkable member of the dinosaur world, presents a fascinating study in adaptation and evolution. This bipedal herbivore, navigating the Late Cretaceous landscape, showcases several unique traits that set it apart from its contemporaries.

One of the most distinctive features of Anabisetia lies at the back of its head. The occipital condyle, the connection point with the neck, pointed downwards, a trait not commonly seen in its Euornithopoda counterparts. This anatomical detail could have implications for how the dinosaur held its head and interacted with its environment.

The shoulder blade of Anabisetia also reveals an intriguing adaptation. It had an extension on its upper lower rim, known as the acromial process, which was relatively the largest ever found in the Euornithopoda. This could suggest a unique muscular structure or a different range of motion, possibly related to its feeding habits or locomotion.

In its hand, the fifth metatarsal was flattened with straight edges, a deviation from the typical rounded cross-section seen in many other species. This feature might have affected its grasping ability or the way it interacted with objects or the environment.

The pelvis of Anabisetia also held unique characteristics. The ilium had a front blade that accounted for more than half of the total ilium length and extended in front of the prepubis. Additionally, the ischium had a shaft that was triangular in cross-section at the upper part and quadrangular lower down. These features could have implications for its mobility and stability as a bipedal creature.

Lastly, in the ankle, the fibula touched the astragalus, a detail that might have influenced its walking or running gait. Each of these unique traits contributes to a fuller understanding of Anabisetia’s physicality and how it might have lived and moved in its natural habitat.

Size and Weight of Type Species

In terms of size, Anabisetia was relatively small compared to many of its dinosaur contemporaries. Gregory Paul, in 2010, estimated its length at about 6.6 feet and its weight at roughly 44.0 pounds. These dimensions paint a picture of a nimble and agile creature, well-suited to a lifestyle that required quick movements, whether for foraging or evading predators.

This modest size also suggests that Anabisetia might have had different survival strategies compared to larger herbivores. Its smaller stature could have allowed it to access food sources that were out of reach for bigger dinosaurs and to navigate through dense vegetation or rugged terrain with greater ease.

Contemporary Dinosaurs

Among its contemporaries were some formidable predators, like the fearsome Megaraptor. This giant, easily towering over Anabisetia, was a predator to be reckoned with. With its large, hook-like claws and swift legs, Megaraptor was the stuff of nightmares for our little herbivore. Imagine Anabisetia, cautiously nibbling on low-lying vegetation, always keeping one eye on the dense ferns that could hide such a terrifying hunter.

Then there was Neuquenraptor, a smaller cousin of the Megaraptor but no less daunting for Anabisetia. Agile and quick, Neuquenraptor could have easily been a threat to our small herbivore. Picture the scene: Anabisetia grazing peacefully, while the shadow of Neuquenraptor slides silently through the underbrush. The tension in the air would be palpable, a game of life and death played out in the dappled sunlight of ancient forests.

But not all of Anabisetia’s contemporaries were threats. Take Patagonykus, for instance, a fellow herbivore, though slightly larger and bulkier. These two might have crossed paths, perhaps competing for the same ferns and low shrubs, but without the inherent danger that came with the likes of Megaraptor and Neuquenraptor. It’s easy to envision a sort of respectful coexistence between Anabisetia and Patagonykus, an unspoken agreement to share the bountiful greenery.

Lastly, there was Unenlagia, roughly the same size as Anabisetia but a carnivore. It’s intriguing to think about their interactions. Were they competitors, with Unenlagia preying on smaller, younger Anabisetias? Or did they simply coexist, aware of each other but not directly interfering? The dance between predator and prey, between competition and coexistence, must have been a delicate one, each creature playing its role in the rich tapestry of their shared ecosystem.

Interesting Points about Anabisetia

Anabisetia in its Natural Habitat

Imagine the world of Anabisetia, a landscape vastly different from our own. During the Late Cretaceous, the Earth was warmer, with higher sea levels and a climate that supported lush, diverse vegetation. This backdrop provided the perfect setting for Anabisetia, a herbivore, to thrive.

In this Cretaceous world, Anabisetia likely roamed in search of vegetation, its diet consisting of the abundant plant life of the era. As a bipedal dinosaur, it would have moved with a certain agility, navigating through dense vegetation or open plains. This mobility was not just for foraging but also played a crucial role in its interactions with predators and other species.

Anabisetia’s role in its ecosystem extends beyond just its diet and locomotion. As a herbivore, it would have played a part in shaping the vegetation patterns of its habitat. Its feeding habits could have influenced plant growth and distribution, making it an integral part of the Cretaceous landscape.

Frequently Asked Questions

What does its name mean?

The name Anabisetia is a tribute to Ana Marie Biset, an influential archeologist from Neuquén Province in Argentina, where the remains of this animal were found.

What type of dinosaur is it?

Anabisetia is classified as an Ornithischia, part of the Iguanodontia.

What did it eat?

As a herbivore, Anabisetia’s diet consisted primarily of plants.

How did it move?

Anabisetia was bipedal, meaning it moved on two legs.

What period did it live in?

It lived during the Late Cretaceous, approximately 93.5 to 89.3 million years ago.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of Anabisetia. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

Article last fact-checked: Joey Arboleda, 11-28-2023

Featured Image Credit: Karkemish, CC BY 3.0, via Wikimedia Commons