Rosa Rubicondior: Refuting Creationism - A Tiny Fish Ancestor of Catfish and Carp - From 70 Million Years Before 'Creation Week'

View of Dry Island Buffalo Leap.

New tiny prehistoric fish species unlocks origins of catfish and carp

A newly discovered fossil fish from the Late Cretaceous has filled a key gap in the evolutionary record of two major freshwater groups – catfish and carp. The fossil was found by researchers from Western University, Ontario, Canada, the Royal Tyrrell Museum of Palaeontology, and international collaborators. Its discovery is bound to send creationists into another bout of denial as they struggle to cope with the cognitive dissonance between reality and their preferred mythology.

When every fossil is transitional, each new find becomes harder for creationists to ignore—unless they retreat to one of their childish parodies of evolution and pretend it means one species instantly transforming into another, as though a ‘species’ consists of a single individual rather than a population, and evolution is a sudden event rather than a gradual process over time. This caricature allows them to dismiss every transitional fossil as a ‘complete species’ with ‘no evidence of intermediates’. From there, they retreat to Bible literalism, invoking vague categories of ‘kinds’ and imagining evolution as one taxon spontaneously giving rise to another—cats turning into dogs, or amoebas becoming humans—something that, if it ever occurred, would indeed defy any scientific explanation.

Hence their constant demands that science provide evidence for their straw-man version of evolution, while they ignore the overwhelming evidence that actually supports evolutionary theory—arguments deliberately crafted to mislead those ignorant of basic biology and to give them spurious reasons to feel smugly superior to ‘elitist scientists’ with their ‘big words’, as though ignorance were a shortcut to expertise.

So they cling to their childish mythology despite the growing number of fossils showing clear mosaic features linking different taxa—exactly what we would expect from ancestral stem species from which two groups diverged. This newly discovered fossil fish from the Late Cretaceous, displaying a mosaic of catfish and carp characteristics, exemplifies that pattern and sheds light on the evolutionary origins of these two major groups of freshwater fish.

Geologic Setting & Age (Dry Island Buffalo Jump, Alberta).

Map and views of Dry Island Buffalo Jump, Alberta, Canada.

Location & landscape

The park lies along the Red Deer River in central Alberta and features classic badlands topography, with deeply incised coulees cutting through sedimentary rock exposures. [1]
A prominent plateau (200 m above the river valley) gives the “dry island” its name, since erosion has isolated it from full river encirclement. [2]
Surficial cover on uplands includes glacial tills; in valley bottoms there is colluvium, alluvium, and some aeolian deposits. [3]

Stratigraphy & depositional environment

The fossil-bearing units in this region are part of the Scollard Formation, the uppermost non-marine (fluvial/floodplain) sedimentary succession of the Western Canada Sedimentary Basin. [4]
The Scollard spans the latest Cretaceous (Maastrichtian) into the early Paleocene (Danian), and includes interfingering sandstones, siltstones, mudstones, shales, coal seams, and bentonite (altered volcanic ash) layers. [4]
It conformably overlies the Battle Formation (also Late Cretaceous) and is overlain by the Paskapoo Formation (Tertiary) in many places. [5]

Age constraints / dating

Palynology (study of fossil pollen/spores) is extensively used in Alberta’s Late Cretaceous–Paleogene strata, and helps distinguish Maastrichtian from Paleocene assemblages in the Scollard. [6]
The K–Pg (Cretaceous–Paleogene) boundary lies within the Scollard — just above the lower coal seam (the “Nevis seam”) — marked by an extinction of dinosaur fossils above that level and microfloral turnover. [7]
Radiometric dating of volcanic ash (bentonite) beds and U–Pb geochronology have refined age limits: for example, high-precision U–Pb dating puts the base of the overlying Scollard at ≈ 66.88 Ma (i.e. just after the Battle Formation) [8]
More broadly, the Cretaceous–Paleogene boundary is commonly placed at ~ 66.0 Ma (or 65.84 ± 0.12 Ma in more recent calibrations) in western North America. [9]

Implications for the fossil

If the fossil is firmly within the Maastrichtian portion of the Scollard, it likely dates to sometime between roughly ~ 68 to 66 million years ago (or possibly slightly earlier, depending on stratigraphic position).
The depositional environment would have been fluvial / floodplain, with intermittent ashfalls (which provide datable horizons) and periodic coal-forming wetlands in the broader floodplain system.
Because the local badland valley cutting (via erosion) post-glacially exposed deeper sedimentary layers, fossils originally buried in the Scollard are now accessible in cliffs and coulee walls. [10]

The fossil, found in Alberta, Canada, is described in a paper in Science and discussed in a Western University news article by Jeff Renaud.

New, tiny prehistoric fish species unlocks origins of catfish and carp
Western researchers collected micro-CT scans showing saltwater species transitioned to freshwater
The fossil of a tiny fish found in southwestern Alberta provides new insight into the origin and evolution of otophysans, the supergroup of fish that includes catfish, carp and tetras, which today account for two-thirds of all freshwater species.

The specimen, studied by researchers at Western University, the Royal Tyrrell Museum of Palaeontology and international collaborators, is a skeleton of a fish about 5 cm long from the Late Cretaceous period (the same time period of the iconic Tyrannosaurus Rex, about 70 million to 66 million years ago.) A new kind of fish entirely, it is now named Acronichthys maccognoi.

A study detailing the discovery was published Oct. 2 in the high impact journal, Science.
The reason Acronichthys is so exciting is that it fills a gap in our record of the otophysans supergroup. It is the oldest North America member of the group and provides incredible data to help document the origin and early evolution of so many freshwater fish living today.

Professor Neil Banerjee, senior author
Department of Earth Sciences
Western University
London, Ontario, Canada.

Banerjee collaborated with an international team including Lisa Van Loon, adjunct Earth sciences professor at Western, Don Brinkman, curator emeritus at the Royal Tyrell Museum, Juan Liu from the University of California, Berkeley and Alison Murray from the University of Alberta.

Otophysans are distinctive in the way the first four vertebrae are modified to transmit vibrations to the ear from the swim bladder (a gas-filled internal organ that allows fish to maintain their position in the water without expending significant energy), basically functioning as a human ear. This is easily spotted in the skeleton of the found fossil of Acronichthys by the naked eye. Van Loon, using synchrotron beamlines at both the Canadian Light Source in Saskatoon, Saskatchewan, and the Advanced Photon Source in Lemont, Illinois, captured a more sophisticated, detailed look with computed tomography (micro-CT) scans.

Micro-CT scans are non-destructive (critical when studying prehistoric fossils), high-resolution X-ray images that create 3D virtual models of objects by taking a series of 2D X-ray projections as an object, in this case the Acronichthys, rotates.

Many of the fossil specimens collected by the Royal Tyrrell Museum are incredibly fragile, and some are impossible to extract from the rock itself, so micro-CT scans provide not only the best method for acquiring detailed images of what’s inside, they’re also the safest way to avoid destroying the fossil all together.

Adjunct Professor Lisa Van Loon, co-author
Department of Earth Sciences
Western University
London, Ontario, Canada.

One fish, two fish, red fish, blue fish

While the discovery of Acronichthys introduces a new species to paleontological records, it also provides critical data to trace the origins of otophysans, as the supergroup is understood to have started as a marine (saltwater) species before transitioning to a freshwater species. The discovery suggests the transition from marine to freshwater species happened at least twice during otophysans’ evolution.

The study estimated a new divergence time for otophysans from marine to freshwater species at around 154 million years ago (the Late Jurassic period) – after Pangea, the supercontinent, began to break apart about 200 million years ago. The researchers are left trying to understand how the tiny Acronichthys moved from continent to continent (as its freshwater ancestors now live on every continent except Antarctica) if they couldn’t swim across saltwater oceans.

X-ray based CT image rendering of Acronichthys maccagnoi fossil.
Lisa Van Loon.

Dinosaurs are pretty exciting, so a lot of time and effort has been focused on them so we know a lot about what they were like, but we’ve only scratched the surface when it comes to understanding the diversity of prehistoric freshwater fish. There’s still so much we don’t know, and a fossil site right here in Canada is giving us the key to understanding the origins of groups that now dominate rivers and lakes around the world.

Donald B. Brinkman, co-corresponding author.
Royal Tyrrell Museum of Palaeontology
Drumheller, Alberta, Canada.
Publication:
Juan Liu et al.
Marine origins and freshwater radiations of the otophysan fishes.
Science 390, 65-69 (2025). DOI:10.1126/science.adr4494

Abstract
Otophysans, known for their enhanced hearing enabled by the complex Weberian apparatus, comprise two-thirds of extant freshwater fish species. Previously, they were thought to have originated in fresh water before the breakup of Pangea, implying a nearly 80-million-year gap between the origin and oldest known fossil. However, the discovery of a Late Cretaceous freshwater otophysan challenges this view. Integrating fossil, morphological, and genomic data, we estimate a younger crown group origin of ~154 million years ago. Notably, ancestral range and habitat reconstructions indicate marine origins for the otophysan crown groups, with at least two transitions to fresh water. Functional simulations of the Weberian ossicles of this fossil suggest that the distinctive hearing capabilities of otophysans evolved in conjunction with fusion of hearing ossicle parts and freshwater adaptations.

Juan Liu et al.
Marine origins and freshwater radiations of the otophysan fishes.
Science 390, 65-69 (2025). DOI:10.1126/science.adr4494

© 2025 American Association for the Advancement of Science.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

Discoveries like this fossil fish from Dry Island Buffalo Jump Provincial Park not only enrich our understanding of evolutionary history but also highlight the power of evidence to illuminate deep time. Each new specimen adds to the intricate picture of how life diversified and adapted, revealing connections that link modern species to their ancient ancestors.

The Cretaceous strata of Alberta have long been a treasure trove of evolutionary evidence, recording the transition from the age of dinosaurs to the rise of modern ecosystems. This latest find underscores how the fossil record, far from being incomplete or contradictory, forms a coherent and continually expanding narrative of life’s gradual transformation.

For those committed to evidence-based science, such discoveries are moments of wonder and confirmation; for creationists, they remain awkward reminders that reality does not conform to mythology. Evolutionary biology continues to build its case layer by layer, fossil by fossil — each one another nail in the coffin of creationist denial.

Creationism can only be maintained by the crudest of intellectual dishonest - denial of the evidence in front of their eyes, and bearing false witness against the scientists who present it. To cling to this religious-based superstition with such blatant dishonesty ultimately leaves science unscathed but does enormous disservice to the religions creationists purport to believe in and the god they purport to worship.

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