F Rosa Rubicondior: Creationism in Crisis - An Ancestral Croccodile from 215 Million Years Before 'Creation Week'

Tuesday 19 March 2024

Creationism in Crisis - An Ancestral Croccodile from 215 Million Years Before 'Creation Week'

An artist’s interpretation of the newly identified aetosaur Garzapelta muelleri
Márcio L. Castro.
Tanks of the Triassic: New Crocodile Ancestor Identified | Jackson School of Geosciences | The University of Texas at Austin

In that very long period of Earth's history, long before creationism's god decided to create a small flat planet with a dome over it, and before even the dinosaurs rose to pre-eminence, another group of reptiles had evolved into armour-plated tank-like creatures with thick body-plates and fringes of curved spikes to deter predators. Some of these were later to evolve into the modern crocodiles.

Now three researchers from the University of Texas at Austin have identified a new species that lived 215 million years ago in the Triassic. The newly-identified species was found on a museum shelf where it had been since its discovery in Garza County in northwest Texas, some 30 years ago by the palaeontologist, Bill Mueller. The researchers have named the new species in his honor, as Garzapelta muelleri (Pelta = plate).
Do you have any information on the Triassic formation in Garza County, Texas, USA? The Triassic formation in Garza County, Texas, USA, primarily consists of sedimentary rocks deposited during the Triassic period, approximately 252 to 201 million years ago. These rocks hold significant geological and paleontological importance, offering insights into the environmental conditions and life forms that existed during that time.

Garza County, located in west-central Texas, is part of the larger Permian Basin, which encompasses various sedimentary formations dating back to the Permian and Triassic periods. The Triassic formations in this area often include sandstones, shales, siltstones, and conglomerates. These sedimentary rocks were typically deposited in terrestrial environments such as rivers, lakes, and floodplains.

One notable aspect of the Triassic formations in Garza County is the presence of fossils. Fossils found in these rocks provide valuable information about the flora and fauna that inhabited the region millions of years ago. Common fossils include those of early reptiles, amphibians, plants, and invertebrates.

In addition to its paleontological significance, the Triassic formation in Garza County also has economic importance. Some areas within the Permian Basin, including Garza County, are known for their hydrocarbon reserves, particularly oil and natural gas. These resources are often found in sedimentary rocks dating back to the Permian and Triassic periods.

Overall, the Triassic formation in Garza County contributes to our understanding of Earth's geological history, paleontology, and the exploration and exploitation of natural resources in the region. Researchers continue to study these formations to uncover new insights into the ancient past and to assess their economic potential.
The researchers have published their finding, sadly behind a paywall, in a special edition of journal Anatomical Record and describe it in a University of Texas news item:
Dinosaurs get all the glory. But aetosaurs, a heavily armored cousin of modern crocodiles, ruled the world before dinosaurs did. These tanks of the Triassic came in a variety of shapes and sizes before going extinct around 200 million years ago. Today, their fossils are found on every continent except Antarctica and Australia.

Scientists use the bony plates that make up aetosaur armor to identify different species and usually don’t have many fossil skeletons to work with. But a new study led by researchers at The University of Texas at Austin centers on an aetosaur suit of armor that has most of its major parts intact.

An artist’s interpretation of the newly identified aetosaur Garzapelta muelleri (spiked reptile in mid- ground on right) and other prehistoric reptiles, amphibians, and mammal relatives. The artwork appears on the cover of a special issue of the Anatomical Record dedicated to Triassic animals.

Credit: Marcio L. Castro.
The suit — called a carapace — is about 70% complete and covers each major region of the body.

We have elements from the back of the neck and shoulder region all the way to the tip of the tail. Usually, you find very limited material.

William Reyes, lead author
Doctoral student
Jackson School of Geosciences
University of Texas, Austing, TX, USA

The research was published in The Anatomical Record, with the aetosaur appearing on the cover along with other Triassic animals.

Reyes and his collaborators used the armor to identify the specimen as a new aetosaur species — which they named Garzapelta muelleri. The name “Garza” recognizes Garza County in northwest Texas, where the aetosaur was found, and “Pelta” is Latin for shield, a nod to aetosaurs’ heavily fortified body. The species name “muelleri” honors the paleontologist who originally discovered it, Bill Mueller.

Garzapelta lived about 215 million years ago and resembled a modern American crocodile — but with much more armor.

“Take a crocodile from modern day, and turn it into an armadillo,” said Reyes.

The bony plates that covered Garzapelta and other aetosaurs are called osteoderms. They were embedded directly in the skin and formed a suit of armor by fitting together like a mosaic. In addition to having a body covered in bony plates, Garzapelta’s sides were flanked by curved spikes that would have offered another layer of protection from predators. Although crocodiles today are carnivores, scientists think that aetosaurs were primarily omnivorous.

William Reyes, a doctoral student at the Jackson School of Geosciences, examines an aetosaur specimen on display at the New Mexico Museum of Natural History and Science.
Credit: William Reyes.
The spikes on Garzapelta are very similar to those found in another aetosaur species, but surprisingly, researchers found that the two species are only distantly related. The similarities, they discovered, are an example of convergent evolution, the independent evolution of similar traits in different species. The development of flight in insects, birds, mammals and now-extinct pterosaurs is a classic example of this phenomenon.

According to Reyes, an array of unique features on Garzapelta’s plates clearly marked it as a new species. They range from how the plates fit together to unique bumps and ridges on the bones. However, figuring out where Garzapelta fit into the larger aetosaur family tree was more of challenge. Depending on which portion of the armor the researchers emphasized in their analysis, Garzapelta would end up in very different places. Armor that ran down its back resembled armor from one species, while its midsection spikes resembled armor from another.

Once the researchers determined that the spikes evolved independently, they were able to work out where Garzapelta fit best among other aetosaur species. Nevertheless, Reyes said the research shows how convergent evolution can complicate things.

A bony plate of armor called an osteoderm from the trunk region of Garzapelta muelleri. Top image is the osteoderm as seen from above. The bottom image is the osteoderm seen from the side. Scale bar is 5 centimeters.

Credit: William Reyes.

Convergence of the osteoderms across distantly related aetosaurs has been noted before, but the carapace of Garzapelta muelleri is the best example of it and shows to what extent it can happen and the problems it causes in our phylogenetic analyses.

William Reyes
Garzapelta is part of the Texas Tech University fossil collections. It spent most of the past 30 years on a shelf before Reyes encountered it during a visit. Bill Parker, an aetosaur expert and park paleontologist at Petrified Forest National Park who was not part of the research, said that university and museum collections are a critical part of making this type of research possible.

These specimens weren’t just dug in the field yesterday. They’ve been sitting in the museum for decades and it just takes someone like Will to come along and finally decide to study them and make them come to life.

Bill Parker, (not involved in the research)
Petrified Forest National Park, Arizona, USA
In addition to different species having different armor, it’s possible that an animal’s age or sex could also affect armor appearance. Reyes is currently exploring these questions by studying aetosaur fossils in the Jackson School’s collection, most of which were found during the 1940s as part of excavations done by the Works Progress Administration.

The study co-authors are Jeffrey Martz, an associate professor at the University of Houston-Downtown, and Bryan Small, a research associate at the Museum of Texas Tech University.

The Late Triassic Dockum Group in northwestern Texas preserves a rich diversity of pseudosuchian taxa, particularly of aetosaurs. In this contribution, we present Garzapelta muelleri gen. et sp. nov., a new aetosaur from the Late Triassic middle Cooper Canyon Formation (latest Adamanian–earliest Revueltian teilzones) in Garza County, Texas, based on an associated specimen that preserves a significant portion of its dorsal carapace. The carapace of G. muelleri exhibits a striking degree of similarity between that of the paratypothoracin Rioarribasuchus chamaensis and desmatosuchins. We quantitatively assessed the relationships of G. muelleri using several iterations of the matrix. Scoring the paramedian and lateral osteoderms of G. muelleri independently results in conflicting topologies. Thus, it is evident that our current matrix is limited in its ability to discern the convergence within this new taxon and that our current character lists are not fully accounting for the morphological disparity of the aetosaurian carapace. Qualitative comparisons suggest that G. muelleri is a Rioarribasuchus-like paratypothoracin with lateral osteoderms that are convergent with those of desmatosuchins. Although the shape of the dorsal eminence, and the presence of a dorsal flange that is rectangular and proportionately longer than the lateral flange are desmatosuchin-like features of G. muelleri, the taxon does not exhibit the articulation style between the paramedian and lateral osteoderms which diagnose the Desmatosuchini (i.e., a rigid interlocking contact, and an anteromedial edge of the lateral osteoderm that overlaps the adjacent paramedian osteoderm).

Reyes, W. A., Martz, J. W., & Small, B. J. (2024).
Garzapelta muelleri gen. et sp. nov., a new aetosaur (Archosauria: Pseudosuchia) from the Late Triassic (middle Norian) middle Cooper Canyon Formation, Dockum Group, Texas, USA, and its implications on our understanding of the morphological disparity of the aetosaurian dorsal carapace.
The Anatomical Record, 307(4), 1271–1299. https://doi.org/10.1002/ar.25379

© 2024 American Association for Anatomy. Published by John Wiley & Sons Inc.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.
It's the same old story of scientists producing yet more evidence that creationist dogmas are wrong because they are based on a mythology written down by ignorant people with no knowledge of the rest of the world outside their small Bronze Age community or of the history of life on Earth. So, creationists will need to fall back on long-refuted lies that the scientists are wrong because either they lied or forged the fossil, or they used a dating method that is so flawed it made 10,000 years or less look like 215 million years, without the slightest understanding of what dating method was used, or the science behind it.

But one question which creationists will run in panic from is why are there no fossils of these creatures after 200 million years ago and no fossils of mammals or birds in the same formations in which these fossil reptiles are found or below them in the geological column?

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