Rosa Rubicondior: Refuting Creationism - Ferocious Ancestor of Crocodiles

Saturday, 30 August 2025

Refuting Creationism - Ferocious Ancestor of Crocodiles - 70 Million Years Before Creation Week

Figure 2. Skull and jaw of Kostensuchus atrox gen. et sp. nov.
Photographs in (A) right lateral, (B) dorsal, and (C) ventral views. Interpretative drawings in (D) right lateral, (E) dorsal, and (F) ventral views. Abbreviations: ang, angular; ap, anterior palpebral; de, dentary; ec, ectopterygoid; fr, frontal; j, jugal; la, lacrimal; mx, maxilla; pa, parietal; pal, palatine; pmx, premaxilla; pnf, perinarial fossa; po, postorbital; pp, posterior palpebral; pt, pterygoid; q, quadrate; qj, quadratojugal; na, nasal; rarp, retroarticular process; sang, surangular; sof, suborbital fossa; spl, splenial; sq, squamosal; stf, subtympanic foramen. Scale bar 5 cm.

Novas FE, et al. (2025)

New crocodile-relative “hypercarnivore” from prehistoric Patagonia was 11.5ft long and weighed 250kg | EurekAlert!

Seventy million years before creationists believe the universe even existed, a ferocious crocodile was prowling the rivers of what is now Brazil. Its fossil remains, recently described in an open-access paper in PLOS One and summarised in a press release from EurekAlert, add yet another line to the mountain of evidence that life has a vast, deep history stretching back hundreds of millions of years.

For creationists, however, discoveries like this present a problem. To remain in the cosy confines of their self-referencing dogma, they must either ignore such evidence or twist it into their narrative that evolution is a Satanic lie and the universe is only a few thousand years old because the Bible says so. Their mission, as they see it, is to defend God’s revealed truth from the “deceptions” of science.

But even if one accepts, for the sake of argument, that a god created the universe and a demonic adversary named Satan exists, the logic collapses under its own weight. Surely it would have been easier for Satan to forge a single book than to fabricate all the astronomical, geological, radiometric, genetic, and fossil evidence pointing to an ancient universe and the evolutionary diversification of life. The alternative is that the creator itself deliberately falsified the evidence science uncovers—yet creationists prefer to believe that this same deceiver told the truth in just one book.

And so the walls of the creationist cult remain, impervious to evidence. But outside those walls, science continues to reveal the true story of life on Earth, in discoveries like this ancient crocodile from long before “Creation Week”—from a time when, according to creationist belief, nothing at all should have existed.

Crocodile evolution is a fascinating story that stretches back more than 200 million years, and the living species we know today are just the latest survivors of a once much larger and more diverse lineage. Here’s a summary of the key points:

Origins – Crocodylomorpha (Late Triassic, ~230 Ma)

Crocodiles belong to the archosaurs, the same major group as dinosaurs and pterosaurs.
The earliest crocodylomorphs were small, lightly built, land-dwelling animals, not the semi-aquatic ambush predators we associate with crocodiles today.
Examples include Hesperosuchus and Saltoposuchus — agile, long-legged hunters more like terrestrial lizards or small theropod dinosaurs.

Rise of Crocodyliformes (Jurassic, ~200–145 Ma)

During the Jurassic, crocodyliforms diversified into a range of ecological niches.
Some were fully terrestrial predators, others herbivores, and some even became marine.
Thalattosuchians (marine crocs) were streamlined, dolphin-like, and adapted to life in the open sea.
This period marks the shift from small, generalised reptiles into a highly specialised and varied group.

Mesoeucrocodylia and Notosuchians (Cretaceous, ~145–66 Ma)

By the Cretaceous, crocodiles were extraordinarily diverse.
Notosuchians (mostly in Gondwana) included bizarre terrestrial forms with unusual dentition, some adapted for omnivory or even herbivory.
Some, like Baurusuchus, were apex land predators, filling niches similar to theropod dinosaurs.
Others evolved armour, long legs, or adaptations for burrowing or specialised feeding.

Modern Lineages Begin (Late Cretaceous)

The ancestors of modern crocodiles (order Crocodylia) emerged around 95–85 million years ago.
This clade includes three living families:

Alligatoridae (alligators & caimans)
Crocodylidae (true crocodiles)
Gavialidae (gharials)

Molecular and fossil evidence suggests these groups diverged before the end-Cretaceous extinction.

Survival and Radiation After the K–Pg Extinction (66 Ma)

Unlike non-avian dinosaurs, crocodylians survived the mass extinction, likely because:

They were semi-aquatic ambush predators, less dependent on land-based ecosystems.
Their ectothermic physiology allowed survival on reduced resources.
Juveniles may have been opportunistic feeders, aiding survival in stressed ecosystems.

After the extinction, most of the odd Cretaceous forms disappeared, leaving mainly semi-aquatic ambush hunters.

Cenozoic Crocodiles (last 66 Ma)

Crocodylians spread worldwide in rivers, lakes, and coastal systems.
Some reached gigantic sizes, like Purussaurus (Amazon Basin, Miocene, up to 10–12 m long).
Others specialised, like the long-snouted Gryposuchus (similar to modern gharials).
Their distribution contracted somewhat with global cooling in the late Cenozoic, but they remain successful tropical predators.

Modern Survivors

Today, there are 26 recognised species of living crocodylians.
Despite their ancient lineage, they are evolutionarily “young” in their present form, with most modern genera appearing within the last 30–40 million years.
They are often described as “living fossils”, but this is misleading: crocodylians have undergone significant evolutionary changes, though their general body plan (elongated body, armour, semi-aquatic lifestyle) has been remarkably effective.

In summary: Crocodiles began as small, land-based archosaurs, radiated into an astonishing variety of forms during the Jurassic and Cretaceous, survived the K–Pg extinction when most of their relatives perished, and evolved into the familiar semi-aquatic predators we know today.

New crocodile-relative “hypercarnivore” from prehistoric Patagonia was 11.5ft long and weighed 250kg
A newly-discovered species of a large, crocodile-relative predator has been described via a remarkably well-preserved fossil from Argentina, according to a study published August 27, 2025, in the open-access journal PLOS One by Fernando Novas from Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Argentina, and colleagues.
The Chorrillo Formation formed around 70 million years ago, during the Maastrichtian age at the very end of the Cretaceous period. At this time, southern Patagonia was a warm, seasonally humid landscape of freshwater floodplains, home to creatures like dinosaurs, turtles, frogs, and various mammals.

The new fossil unearthed in this formation is largely intact, including a skull and jaws with visible details, as well as multiple bones from the body. This crocodile-like apex predator may have reached around 3.5 meters (11.5 feet) long and weighed around 250 kilograms (551 pounds), with a wide, powerful jaw and big teeth capable of devouring large prey — likely including medium-sized dinosaurs. The researchers named the species Kostensuchus atrox, referring to the Patagonian wind known in the Tehuelche native language as the Kosten and the Egyptian crocodile-headed god known as Souchos, with atrox meaning “fierce” or “harsh”.

K. atrox itself is not a dinosaur, but rather a peirosaurid crocodyliform, an extinct group of reptiles related to modern crocodiles and alligators. This species is the second-largest predator known to scientists from the Maastrichtian Chorrillo Formation, and the researchers believe it was likely one of the top predators in the region. K. atrox is also the first crocodyliform fossil found in the Chorrillo Formation, and one of the most intact peirosaurid crocodyliforms ever found, giving scientists unique new insight into these prehistoric animals and their ecosystem.

Publication:
Novas FE, Pol D, Agnolín FL, Carvalho IdS, Manabe M, Tsuihiji T, et al. (2025)
A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina. PLoS One 20(8): e0328561. https://doi.org/10.1371/journal.pone.0328561

Abstract
The first crocodyliform specimen from the Maastrichtian Chorrillo Formation (Austral Basin, Patagonia) is here described. The discovery was made about 30 km to the SW of the town of El Calafate (Province of Santa Cruz, Argentina) and consists of a beautifully preserved and articulated skull and jaws, and part of the postcranial skeleton that were preserved encased in a large concretion. This new taxon belongs to the notosuchian clade Peirosauridae, representing the latest and southernmost record for this group of crocodyliforms. The new taxon is recovered as closely related to other robust and broad-snouted peirosaurids that lived by the end of the Cretaceous Period, such as Colhuehuapisuchus from the Maastrichtian of Central Patagonia and Miadanasuchus oblita from the Maastrichtian of Madagascar. The completeness of the new specimen reveals, for the first time, the anatomy and body plan of a large and broad snouted peirosaurid. The new taxon bears large ziphodont teeth, a broad oreinirostral snout that is only slightly longer than 50% the skull length, and a deep adductor chamber in the temporal region and posterior mandibular ramus. The anterior region of its postcranial skeleton is preserved and shows broad scapula and a robust humerus features previously known in large predatorial notosuchians. The new crocodyliform adds to the predatorial component of terrestrial ecosystems at high paleolatitudes by the end of the Cretaceous Period.

Introduction
The end of the Cretaceous Period is particularly well recorded in Patagonia [1,2]. In recent years a large collecting effort has resulted in a high number of new vertebrate records in different basins of Patagonia, including the discovery of new and diverse faunal associations in central [e.g., 3,4] and southern [e.g., 5–7] Patagonia that complements previous knowledge from the Neuquén Basin in northern Patagonia [e.g., 1,8–11]. Among the records from the Austral Basin, the most noteworthy are those from the Campanian Cerro Fortaleza [e.g., 6] and the Maastrichtian Chorrillo formations [e.g., 5,12] in Argentina, and Cerro Dorotea Formation in southern Chile [e.g., 7,13].

The Chorrillo Formation crops out in the SW corner of Santa Cruz Province, in Argentine Patagonia (Fig 1). These beds are particularly interesting as they have yielded a wide array of fossils from a Maastrichtian terrestrial ecosystem [5,12], including pollen and spores [14], plant remains [15], freshwater and terrestrial invertebrates [16], fishes, frogs, and turtles. Dinosaurs recovered from these beds include the elasmarian Isasicursor santacrucensis [5,17,18], the large titanosaur Nullotitan glaciaris [5], the megaraptorid coelurosaur Maip macrothorax [18], the birds Kookne yeutensis and Yatenavis iujensis [5,19], as well as indeterminate parankylosaurs and hadrosaurids [17]. The vertebrate fossil assemblage also includes representatives of different mammalian clades, including monotremes, gondwanatherians, meridiolestidans, and therians [20–22].
The Chorrillo Formation crops out in the SW corner of Santa Cruz Province, in Argentine Patagonia (Fig 1). These beds are particularly interesting as they have yielded a wide array of fossils from a Maastrichtian terrestrial ecosystem [5,12], including pollen and spores [14], plant remains [15], freshwater and terrestrial invertebrates [16], fishes, frogs, and turtles. Dinosaurs recovered from these beds include the elasmarian Isasicursor santacrucensis [5,17,18], the large titanosaur Nullotitan glaciaris [5], the megaraptorid coelurosaur Maip macrothorax [18], the birds Kookne yeutensis and Yatenavis iujensis [5,19], as well as indeterminate parankylosaurs and hadrosaurids [17]. The vertebrate fossil assemblage also includes representatives of different mammalian clades, including monotremes, gondwanatherians, meridiolestidans, and therians [20–22].

Fig 1. Map of the fossil locality of Kostensuchus gen. nov.
The map shows the locality in southern Patagonia (Santa Cruz Province, Argentina). Modified from [5].
https://doi.org/10.1371/journal.pone.0328561.g001

Here, we expand the diversity of fossil vertebrates from the Chorrillo Formation with the description of the peirosaurid crocodyliform Kostensuchus atro nov. gen. et sp., represented by an exquisitely preserved and articulated skeleton, lacking some of the limb bones and tail (S1 File). This specimen is one of the best preserved and anatomically informative peirosaurid crocodyliform yet recorded, and the most complete representative of robust, broad snouted members of this clade. The new taxon was a large predator, approximately 3.5 meters long (estimation based on extrapolations with complete skeletons of Caiman and Alligator), second in size, among predators, only to the megaraptorid theropod Maip (ca. 9 meters) [18] known from the Chorrillo Formation. Kostensuchus reveals the craniomandibular anatomy and body plan of the large and robust peirosaurids that survived until the end Cretaceous in South America and Madagascar, and provides the southernmost record of this diverse crocodyliform clade. The record of Kostensuchus contributes to characterize the faunal association from the Maastrichtian of southern Patagonia (Austral Basin), and underscores the differences among coeval terrestrial ecosystems in central and northern Patagonia (Cañadón Asfalto and Neuquén basins).

Fig 3. Skull and jaw of Kostensuchus atrox gen. et sp. nov.
Photographs and interpretative drawings in (A-B) anterior and (C-D) posterior views. Abbreviations: ang, angular; ap, anterior palpebral; art, articular; bs, basisphenoid; co, occipital condyle; de, dentary; fa, foramen aërum; fo, perinarial foramen; fr, frontal; j, jugal; la, lacrimal; mx, maxilla; ot, otoccipital; pa, parietal; pmx, premaxilla; pnf, perinarial fossa; p pp, posterior palpebral; pro, proatlas; pt, pterygoid; ptp, posterior pterygoid process; q, quadrate; qj, quadratojugal; na, nasal; rarp, retroarticular process; sang, surangular; socc, supraoccipital; sq, squamosal. Scale bar 5 cm

Fig 4. Details of rostral anatomy of Kostensuchus atrox gen. et sp. nov.
Photographs of right antorbital region in lateral view (A) and left surface of rostrum in anterolateral view (B). Abbreviations: afe, antorbital fenestra; ap, anterior palpebral; lab, lacrimal bulge; j, jugal; lad, lacrimal depressed surface; gr, longitudinal groove of maxilla; j, jugal; mx, maxilla

Fig 5. Virtual threedimensional model of anterior region of lower jaw of Kostensuchus atrox gen. et sp. nov.
Model in (A) dorsal, (B) ventral, (C) anterior, and (D) right lateral views. Abbreviations: de, dentary; spl, spenial; spp, splenial peg. Scale bar 5 cm.

Fig 6. Skeletal reconstruction of Kostensuchus atrox gen. et sp. nov.
Three-dimensional model in left lateral view with preserved bone in light brown and missing elements in light grey. Missing elements were modeled based on selected notosuchians for which these regions are known (e.g., Montealtosuchus, Araripesuchus), as well as extant crocodylians (Caiman). Scale bar 5 cm.

Fig 7. Cervical vertebrae of Kostensuchus atrox gen. et sp. nov.
Threedimensional model of cervicals, from the axis to the seventh cervical vertebrae in (A) left lateral, (B) ventral, and (C) left lateroventral views. Abbreviations: cr, cervical rib; hy, hypapophysis; ns, neural spine; ost, dorsal osteoderm; pp, parapophysis; prz, prezygapophysis. Scale bar 5 cm.

Fig 8. Dorsal vertebrae of Kostensuchus atrox gen. et sp. nov.
Threedimensional model in (A) left ventral, (B) left lateral, and (C) dorsal views of fourth dorsal vertebra (D4) to twelfth dorsal vertebra (D12). Abbreviations: di, diapophysis; hy, hypapophysis; ns, neural spine; ost, dorsal osteoderm; pp, parapophysis; poz, postzygapophysis; prz, prezygapophysis. Scale bar 5 cm.

Fig 9. Shoulder girdle of Kostensuchus atrox gen. et sp. nov.
Threedimensional model in (A) left lateral view. Abbreviations: cf, coracoid foramen; cgf, coracoid glenoid facet; cor, coracoid; sc, scapula; sgf, scapular glenoid facet; ost, osteoderm. Scale bar 5 cm.

Fig 10. Humerus of Kostensuchus atrox gen. et sp. nov.
Threedimensional model in (A), lateral, (B), posterior, (C), medial, and (D), anterior views. Abbreviations: adf, anterior distal fossa; dpc, deltopectoral crest; dsh, humeral distal shelf; pdf, posterior distal fossa; scr, supracondylar crests. Scale bar 5 cm.

Fig 11. Ilium of Kostensuchus atrox gen. et sp. nov.
Threedimensional model in (A) lateral view. Abbreviations: is, ischium; isp, ischial peduncle; it, insertion area of M. iliotibialis; pap, preacetabular process; pop, postacetabular process; pp, pubic peduncle; ost, dorsal osteoderm; sac, supracetabular crest. Scale bar 5 cm.

Fig 12. Phylogenetic relationships of Kostensuchus atrox gen. et sp. nov.
Reduced strict consensus tree obtained in the phylogenetic analysis. Thick bars in terminal branches represent the chronostratigraphic uncertainty for each taxon. Phylogenetic tree was calibrated using the R package Paleotree [81].

[…]

Conclusions
The discovery of Kostensuchus atro gen. et sp. nov. considerably expands the knowledge about the anatomy of broad-snouted peirosaurids, previously known from extremely fragmentary remains from South America and Madagascar. Kostensuchus gen. nov. is retrieved as part of a clade of robust, broad-snouted peirosaurids that existed at the end of the Cretaceous across various regions of Gondwana. The new anatomical information provided by Kostensuchus gen. nov. sheds light on both, the similarities and differences between broad-snouted peirosaurids and baurusuchids, the other crocodyliform clade that independently evolved into apex predators during the Cretaceous of Gondwana.

Kostensuchus gen. nov. formed part of the latest Cretaceous ecosystem of southern Patagonia, in a freshwater ecosystem under a temperate to warm climate with seasonal humidity, alongside a diverse fauna of dinosaurs, mammals, and other vertebrates. The broad and high snout of Kostensuchus gen. nov., with notably large and robust ziphodont teeth, along with a broad adductor chamber in the skull and deep mandibular ramus, and robust forelimb anatomy suggests that the new species was capable of subduing large prey. These features imply that Kostensuchus gen. nov. played the role of a top predator within this end-Cretaceous ecosystem.

Novas FE, Pol D, Agnolín FL, Carvalho IdS, Manabe M, Tsuihiji T, et al. (2025)
A new large hypercarnivorous crocodyliform from the Maastrichtian of Southern Patagonia, Argentina. PLoS One 20(8): e0328561. https://doi.org/10.1371/journal.pone.0328561

Copyright: © 2025 The authors.
Published by PLoS. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Discoveries like Kostensuchus atrox reveal a world unimaginably older and stranger than creationist dogma allows—a predator that lived 70 million years before their supposed “Creation Week,” in a time when, by their reckoning, nothing at all should have existed. The fossil is real, the evidence is clear, and the science that explains it is open for anyone to examine.

And yet, for creationists, such evidence can never be allowed to penetrate. Their walls are already built: every fossil, every rock layer, every radiometric date must be dismissed as deception, every scientist condemned as an agent of doubt. Their barricade is not a defence of truth but a shelter from it.

While science dismantles ignorance and brings us closer to reality, creationism reinforces its own self-made prison. The crocodile’s skull stands as a reminder that the universe is not bound by ancient texts or human dogmas, but by evidence. And evidence, unlike belief, needs no protection from the real world.

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