Rosa Rubicondior: Creationism in Crisis - This Fossil Marsupial is Thirteen Thousand Times Older Than The Universe, According to Creationists

Anachlysictis gracilis stalking its prey in the La Venta area of Colombia, 13 million years ago. (artists impression)

Credit: Juan Giraldo

Prehistoric predator | Smithsonian Tropical Research Institute

Scientists have unearthed the fossilised remains of a predatory sabre-toothed marsupial that lived in what is now Columbia in northwestern South America, 13 million years ago, during the Cenozoic, the period which followed the extinction of the dinosaurs, which cleared the way for a rapid diversification of mammals.

The fossil is of Anachlysictis gracilis, one of the family of predatory marsupial known as the Thylacosmilidae.

What information do you have on the extinct marsupial family Thylacosmilidae? Thylacosmilidae is an extinct family of marsupials that lived in South America during the Late Miocene to Early Pliocene epochs, approximately 7 to 3 million years ago. These marsupials are notable for their specialized dentition, which suggests they were carnivorous predators. Thylacosmilids are often referred to as "marsupial sabertooths" because of their strikingly similar appearance to the saber-toothed cats (such as Smilodon) from North America. Here are some key features and information about Thylacosmilidae:

Saber-Toothed Appearance: Thylacosmilids had elongated, saber-like upper canine teeth, similar to the saber-toothed cats. These teeth were likely used for puncturing and capturing prey.

Convergent Evolution: The resemblance between thylacosmilids and saber-toothed cats is considered a remarkable example of convergent evolution, where two unrelated groups of animals develop similar adaptations in response to similar ecological roles.

Size: Thylacosmilids came in different sizes. Some were relatively small, around the size of a domestic cat, while larger species could be as big as a leopard.

Diet: Their specialized dentition and sharp canines suggest that they were carnivorous, preying on other mammals. Their diet likely consisted of small to medium-sized herbivorous mammals.

Marsupial Characteristics: Despite their striking similarity to saber-toothed cats, thylacosmilids were marsupials, which is a distinctive group of mammals characterized by giving birth to undeveloped offspring and often carrying them in a pouch.

Fossils: Fossils of thylacosmilids have been found in various locations in South America, particularly in Argentina and Bolivia. These fossils have provided valuable insights into the anatomy and lifestyle of these unique creatures.

Extinction: Thylacosmilids, like many other prehistoric animals, became extinct at the end of the Pliocene epoch, likely due to environmental changes and competition with other carnivores. The exact reasons for their extinction are still a subject of research and debate.

While Thylacosmilidae is an extinct family, it offers a fascinating glimpse into the diverse and unique mammalian fauna of prehistoric South America and the fascinating phenomenon of convergent evolution in the animal kingdom.

The excavation was conducted by a team of paleaontologists led by Dr. Catalina Suarez, a Swiss National Science Foundation fellow working at the Argentine Institute of Nivology, Glaciology and Environmental Sciences. Their results are published in the journal Geodiversitas., available as a downloadable pdf.

The research and its significance are explained in a Smithsonian Institute news release:

A 13-million-year-old saber-toothed marsupial skeleton discovered during paleontological explorations in Colombia is the most complete specimen recovered in the region

Recent paleontological explorations in the Tatacoa Desert in Colombia led to the recovery of the most complete skeleton of a "saber-toothed marsupial” discovered in northern South America. The specimen belongs to the species Anachlysictis gracilis, which is part of a group of extinct predatory mammals known as sparassodonts, that lived in South America during the Cenozoic, after the extinction of the dinosaurs.

This species lived approximately 13 million years ago in the area known among paleontologists as ‘La Venta’, in the current La Tatacoa desert, a tropical dry forest that “at that time was a tropical rainforest, similar to the current Amazon,” said Dr. Catalina Suarez, a Swiss National Science Foundation fellow working at the Argentine Institute of Nivology, Glaciology and Environmental Sciences, who led the analysis of the remains and the publication of their results in the scientific journal Geodiversitas.
Scheme of the skeleton of Anachlysictis gracilis with the recently discovered remains.

Credit: Photography and design: Daniella Carvalho and Aldo Benites-Palomino.

Lead author Catalina Suarez (IANIGLA, Argentina, center) and co-author Javier Luque (University of Cambridge Museum of Zoology, UK) excavating Miocene vertebrates in the La Venta area where the saber-toothed marsupial was discovered.
Credit: Felipe Villegas (Humboldt Institute).

Prior to this finding, only a piece of a mandible and few additional remains had been found for this species related to living marsupials such as kangaroos, koalas, or opossums. Before it disappeared, A. gracilis was one of a number of terrestrial carnivores in South America, like the pumas, wildcats, foxes, bears and others that currently roam our continent.

Thanks to this discovery, we were able to learn new details about this fascinating species. The analyses allowed us to understand what these extinct predators were like and how they lived in Neotropical South America millions of years ago.>/p>
Dr. Catalina Suarez, first author.
Instituto Argentino de Nivología
Glaciología y Ciencias Ambientales (IANIGLA)
Mendoza, Argentina.

Suarez began her research on A. gracilis in the laboratory of paleontologist Carlos Jaramillo at the Smithsonian Tropical Research Institute, where she was an intern and a pre- and post-doctoral fellow. She is now a specialist in metatherians, the group that includes marsupials and their extinct relatives, such as the family of Thylacosmilidae to which the fossil of A. gracilis belongs. The most peculiar feature of this family is their curved and flattened canines, resembling the shape of a saber, so they are commonly known as "saber-toothed marsupials".

Extraction of the new specimen (the left side of the mandible, which was still buried, can be observed).

Credit: Aldo Benites-Palomino.

Jaw fragment of the new specimen of Anachlysictis gracilis at the time of discovery.

Credit: Aldo Benites-Palomino.

Our research confirms that this Colombian fossil ‘saber-tooth marsupial’ A. gracilis, is closely related to Thylacosmilus, which is the most widely recognized ‘saber-tooth marsupial. Both groups, together with Patagosmilus (another one of these ‘saber-tooth marsupials’), form their own family in the mammal tree of life, known as Thylacosmilidae. This family is characterized by its long and enormous curved and saber-shaped upper canines, and by an extension of the anterior part of the jaw that looks like the sheath of said 'sabers.

Dr. Javier Luque, co-author
Senior research associate
University of Cambridge Museum of Zoology.
By analyzing the molar teeth, tooth shape and mandible of the remains, it was possible to define the approximate weight and diet type of A. gracilis. The results revealed that it weighed on average about 23 kg (like a lynx) and was a hypercarnivore that ate only meat, not bone. Its potential prey would have included small mammals that inhabited the area, such as marsupials, spiny rats, porcupines, rodents of various sizes and even primates, which were very abundant in the region.

In a future study we will address all the other bones in its body, which include various sections of the spine, ribs, hip, scapulae —what we call 'shoulder blades' for humans— and bones in its legs. This will allow us to explore aspects of how it moved, the position in which its neck held its head, whether it was a runner, whether it could climb, whether its hands could hold objects more easily, as many marsupials do when feeding, or whether it was a bit more difficult, as it is for example for a dog or a cat.

Dr. Catalina Suarez

Skull of Anachlysictis gracilis after its discovery.
Credit: Aldo Benites-Palomino.

The three species of the family Thylacosmilidae on the South American continent: Anachlysictis gracilis (left, above), Thylacosmilus atrox (right) and Patagosmilus goini (left, below)

Credit: Jorge Blanco.

The new fossil of A. gracilis is housed in the La Tatacoa Natural History Museum, in the town of La Victoria in the municipality of Villavieja (department of Huila, Colombia), along with other surprising finds that have been unearthed in one of the most amazing places on the continent.

The fossil specimen of A. gracilis that we describe in this research constitutes an iconic fossil because of its excellent preservation, three-dimensionality, and importance for understanding the paleobiological aspects of this predatory marsupial that roamed the forests of northern South America approximately 13 million years ago. With this finding we show the importance of continuing to support paleontological scientific activity in the Neotropics, in order to be able to make new discoveries that will help us understand the evolutionary history and paleobiodiversity of this part of the continent.

Dr. Edwin Cadena, co-author
Universidad del Rosario and STRI

Current landscape in one of the fossiliferous localities of the La Tatacoa desert.
Credit: Catalina Suarez.

This research was the result of an international collaboration between specialists representing institutions from Argentina (IANIGLA-CCT Conicet Mendoza, Museo de La Plata and Unidad Ejecutora Lillo-CONICET, Fundación Miguel Lillo), Colombia (Universidad del Rosario and Museo de Historia Natural La Tatacoa), United States (Field Museum of Natural History), Japan (Ashoro Museum of Paleontology), Panama (Smithsonian Tropical Research Institute) and United Kingdom (University of Cambridge).

The skulls of an extant opossum (bottom left) and the extinct saber-tooth marsupial Anachlysictis gracilis (top right) from the Miocene of Colombia. Museo de Historia Natural La Tatacoa.

Credit: Javier Luque (University of Cambridge Museum of Zoology, UK)

In the abstract to their published paper, the authors say:

This article is a part of the thematic issue Neotropical palaeontology: the Miocene La Venta biome The fossil metatherian assemblage from La Venta (Middle Miocene, Colombia) is one of the most diverse in South America, and it is critical to understand the Neogene radiation of this group in this continent. La Venta contains the northernmost record of Thylacosmilidae Riggs, 1933 (Metatheria, Sparassodonta): Anachlysictis gracilis Goin, 1997, the first thylacosmilid species named for the Neotropics. This taxon was described mostly based on mandibular remains. Recent fieldwork and work in collections led to the discovery of new materials for this species, including the most complete skeleton ever found for this Sparassodonta Ameghino, 1894. Here, we present a detailed description of the cranial osteology and dentition of A. gracilis, which elucidates anatomical aspects previously inferred but hitherto unconfirmed. We investigate the phylogeny, and ecomorphological parameters of this taxon (diet and body mass) to set the evolutionary context of the species, understand its paleobiology, and evaluate palaeoecological implications. Additionally, we revise the phylogeny of the thylacosmilids, recovering the traditional classification of the group, differentiated from the proborhyaenids and borhyaenids. This work also proposes a new reconstruction of the external morphology of the head of A. gracilis based on 3D scans of the new referred materials.

SUAREZ C., FORASIEPI A. M., BABOT M. J., SHINMURA T., LUQUE J., VANEGAS R. D., CADENA E.-A. & GOIN F. J. 2023.
A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia), in CARRILLO J. D. (ed.), Neotropical palaeontology: the Miocene La Venta biome.
Geodiversitas 45 (18): 497-572. https://doi.org/10.5252/geodiversitas2023v45a18.

© 2023 MUSÉUM NATIONAL D'HISTOIRE NATURELLE.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

Faced with the deluge of evidence for an Earth much older than creationists believe it to be from their reading of the Bible, normal people might begin to question the reliability in scientific/historical matters of their source book and wonder whether scientific sources might be more reliable - assuming they were interested in the truth.

However, it seems creationists prefer to cling to the excuse for posing as more expert than the experts without all the bother of learning. They seem to have been fooled into believing the best way to become a leading expert in a subject is to remain completely ignorant of it, and just pretend, whilst trying to make a virtue of the intellectual and moral bankruptcy that goes with such willful self-deception, by calling it 'faith'.