Unintelligent Design - Vestigial 'Fossil' Ear Muscles Still Try to Function

Muscles of the head

AI-generated image (with AI spelling)

Muscles of the ear

Image by BioDigital, edited by Lecturio

‘A neural fossil’: human ears try to move when listening, scientists say | Biology | The Guardian

In my book, The Body Of Evidence: How the Human Body Refutes Intelligent Design I list very many examples of the sort of design only a fool would produce - examples of sub-optimal compromises in structures and processes that could have been less error-prone and more efficient in terms of resource use or function.

These also included vestigial structures and system that still exist, sometime causing problems such as appendicitis when the functionless appendix becomes infected, and the wasted metabolism in making all the tiny hairs on your body stand up in cold weather using the tiny arrector pili muscles and the autonomic nerves that supply them.

Now we have another example, involving the superior and posterior auricular muscles that once moved the ears in a remote simian ancestor, but now only serve as party tricks for the few of us that can wiggle our ears.

Refuting Creationism - How Horseshoe Crabs Have Evolved And Diversified

Indo-pacific horseshoe crab, Tachypleus gigas

By Shubham Chatterjee - Own work,
CC BY-SA 3.0, Link

Indo-Pacific Horseshoe Crab, Tachypleus tridentatus

Photo: Dr Tang Qian

Preserving Asian horseshoe crab populations through targeted conservation strategies

In creationist mythology, horseshoe crabs have remained unchanged for 400 million years, so they prove there is no such thing as evolution and Earth is only 6-0,000 years old. Apart from the typical lack of joined-up thinking in that non sequitur, there are a couple of fallacy at work here.

Firstly, evolution does not necessarily involve major changes in the phenotype because it happens at the genetic level, so the genome is where we need to look to find evidence of it (or lack of it); secondly there is no requirement for a species that is already adapted to its environment to change unless its environment changes in a way that requires adaptation. This might include increased predation, depletion of food resource, major changes in temperature or oxygenation, increased competition from another species, etc.

With their child-like understanding of evolution, creationists assume a species must change into something else for evolution to happen.

In fact, as a team a research team led by Associate Professor Frank Rheindt from the Department of Biological Sciences at the National University of Singapore (NUS) Faculty of Science have now shown, there are four different species of horseshoe crab which have all diversified from a common ancestor.

Tell me about the evolution and distribution of the horseshoe crabs, please. Horseshoe crabs (order Xiphosura, class Merostomata) are marine arthropods that have existed for over 450 million years, making them one of the oldest living groups of animals. They are often called "living fossils" because their body plan has remained largely unchanged since the Ordovician period.

Evolutionary History

Horseshoe crabs belong to the subphylum Chelicerata, making them more closely related to arachnids (such as spiders and scorpions) than to true crabs or other crustaceans. Their evolutionary history includes several now-extinct relatives, such as Eurypterids (sea scorpions), which were once dominant marine predators.

• Ordovician Period (~450 mya): Early xiphosurans appear in shallow marine environments.
• Paleozoic Era (~300 mya): More advanced forms develop but remain morphologically similar to modern species.
• Mesozoic Era (~150 mya): Horseshoe crabs survive mass extinctions, adapting to various shallow marine environments.
• Cenozoic Era (Present day): Four extant species remain, showing remarkable evolutionary stability.

Modern Distribution

Today, only four species of horseshoe crabs survive, all found in coastal and estuarine environments:

1. Limulus polyphemus (Atlantic Horseshoe Crab) – Found along the eastern coast of North America, from the Gulf of Mexico to the northeastern United States.
2. Tachypleus tridentatus (Tri-spine Horseshoe Crab) – Found in coastal waters of China, Japan, and Southeast Asia.
3. Tachypleus gigas (Indo-Pacific Horseshoe Crab) – Inhabits the waters of the Bay of Bengal and Southeast Asia.
4. Carcinoscorpius rotundicauda (Mangrove Horseshoe Crab) – Found in shallow waters and estuaries from India to Indonesia.

Ecological Role & Conservation

Horseshoe crabs play a crucial ecological role. Their eggs provide an important food source for migratory shorebirds, and they contribute to benthic (seafloor) ecosystems. They are also vital to biomedical research because their blue blood contains limulus amebocyte lysate (LAL), used to detect bacterial contamination in medical applications.

However, populations are declining due to:

• Overharvesting (for bait and biomedical use)
• Habitat loss (coastal development)
• Climate change (affecting spawning conditions)

Conservation efforts focus on protecting nesting beaches, regulating harvesting, and exploring synthetic alternatives to LAL for medical testing.

Fossil Record of Horseshoe Crabs (Order Xiphosura)

Horseshoe crabs have an extensive fossil record dating back to the Ordovician period (~450 million years ago). Their morphology has remained remarkably stable, making them classic examples of "living fossils." The fossil record reveals several extinct relatives and a gradual adaptation to different marine environments over geological time.

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Key Fossil Discoveries and Evolutionary Timeline

1. Ordovician Period (485–443 mya) – Oldest Known Horseshoe Crab Ancestors
   • The earliest xiphosurans appeared in shallow marine environments.
   • Fossils of Tetraspidella from the Upper Ordovician suggest primitive horseshoe crab-like arthropods already existed.
2. Silurian Period (443–419 mya) – Emergence of True Xiphosurans
   • More recognizable horseshoe crab relatives evolved.
   • Kasibelinurus (Late Silurian) is considered one of the earliest known xiphosurans.
3. Devonian Period (419–359 mya) – Diversification and Expansion
   • This period saw the emergence of several marine genera with more developed carapaces and feeding structures.
   • Bellinurus and Euproops are well-known genera from the Devonian.
4. Carboniferous Period (359–299 mya) – Peak Diversity
   • This was the golden age of xiphosurans, with numerous species thriving in marine, brackish, and even freshwater environments.
   • Genera like Euproops, Bellinurus, and Paleolimulus flourished, some resembling modern horseshoe crabs.
   • Some species, such as Euproops danae, had spines and unique adaptations to different ecological niches.
5. Permian Period (299–252 mya) – Decline and Extinctions
   • The Permian saw a decline in diversity, possibly due to changing environments and competition with other arthropods.
   • Many species perished during the Permian-Triassic mass extinction (~252 mya), the most severe extinction event in Earth's history.
6. Mesozoic Era (252–66 mya) – Survival and Adaptation
   • Xiphosurans survived the mass extinction but were less diverse than in the Carboniferous.
   • Fossil genera like Mesolimulus (Jurassic) and Limulitella (Cretaceous) were similar to modern horseshoe crabs.
   • Some species adapted to shallow coastal waters, much like their modern counterparts.
7. Cenozoic Era (66 mya–Present) – Modern Horseshoe Crabs
   • Fossil records show that Limulus polyphemus, the modern Atlantic horseshoe crab, has remained almost unchanged for at least 20 million years.
   • Their ability to survive drastic environmental changes has made them one of the longest-surviving arthropod groups.

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Key Fossil Finds

1. Kasibelinurus (Silurian) – One of the earliest known true xiphosurans.
2. Euproops (Carboniferous) – Small, with a reinforced carapace and spines for protection.
3. Mesolimulus (Jurassic) – Nearly identical to modern Limulus, showing little evolutionary change.
4. Paleolimulus (Permian) – A transitional form between early and modern horseshoe crabs.

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Why Have Horseshoe Crabs Changed so Little?

• Stable ecological niche: They have occupied similar coastal and estuarine environments for hundreds of millions of years.
• Efficient body plan: Their tough exoskeleton, simple yet effective feeding structures, and ability to tolerate low-oxygen conditions have helped them persist.
• Survivors of mass extinctions: They have outlived dinosaurs and many other ancient marine species due to their resilience and adaptability.

The results of their study are published open access in the journal Conservation Letters and is the subject of a news item from NUS>

Preserving Asian horseshoe crab populations through targeted conservation strategies

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NUS biologists conduct the first comprehensive population study of all three Asian horseshoe crab species, mapping their population distribution, evolutionary histories and vulnerabilities to climate change to propose customised conservation strategies

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The photo shows the moult of a young tri-spine horseshoe crab, Tachypleus tridentatus – an endangered species – found on the beach at Beihai, China. The genomic data gathered by NUS researchers on this species provides a launchpad for conservation strategies.

Photo: Dr Tang Qian.

Horseshoe crabs are often referred to as the “living fossils” of our planet — the four known species, including three in Asia and one in North America, remain nearly identical to their ancient relatives from hundreds of millions of years ago. These arthropods are a fundamental building block of coastal marine ecosystems. Their eggs, for example, serve as a major food source for shorebirds, some of which have evolved to time their migrations to coincide with peak horseshoe crab spawning activity. In addition to their ecological role, horseshoe crabs are also used in biomedicine to test for harmful toxins in vaccines.

Among the four species, only the Atlantic horseshoe crab (Limulus polyphemus), found along the Atlantic coast of the United States and the Gulf of Mexico, has been extensively studied. In contrast, scientific information about the three Asian species is so scant and scattered that the IUCN Red List, which tracks the extinction risk of species around the world, listed two of them (the mangrove horseshoe crab and the coastal horseshoe crab) as “data deficient”. This designation indicates insufficient data to assess their extinction risk. On the other hand, the tri-spine horseshoe crab is considered endangered.

Understanding our planet’s living fossils

to help fill in these knowledge gaps, a research team led by Associate Professor Frank Rheindt from the Department of Biological Sciences at the NUS Faculty of Science conducted the first comprehensive population genomic study of all three Asian horseshoe crab species: the mangrove horseshoe crab (Carcinoscorpius rotundicauda), coastal horseshoe crab (Tachypleus gigas), and tri-spine horseshoe crab (Tachypleus tridentatus).

The study underscores the importance of Southeast Asia’s Sunda Shelf, a shallow-marine region, as a critical coastal marine habitat. Importantly, this region has sustained the survival of these ancient arthropods for millennia and could continue to act as a refuge for Asian horseshoe crabs amid accelerating anthropogenic climate change.

The researchers have also established the first-ever genomic baseline dataset for these species, which lay the groundwork for targeted conservation planning. Their findings, which propose different conservation strategies for each species, were published in Conservation Letters on 16 December 2024.

Back to the basics: Filling data gaps to advance conservation efforts

To protect and conserve these species, it is crucial that we first cover the basics — understanding their population structure, evolutionary histories and climate-change-driven vulnerabilities. This foundational knowledge will enable us to develop targeted conservation strategies and prioritise habitats critical for their survival.

Associate Professor Frank E. Rheindt, co-corresponding author
Department of Biological Sciences
National University of Singapore, Singapore.

Tracking and monitoring Asian horseshoe crabs is in and of itself a challenging feat. They spend most of their lives on the seabed, making them difficult to observe, and they take 14 years to mature — too long to assess population changes effectively through traditional surveys. To overcome these challenges, the researchers turned to population genomic approaches, where they analysed DNA from 251 horseshoe crabs collected across 52 sites in 11 countries.

Using this data, NUS researchers created the first genomic baseline dataset for Asian horseshoe crabs. This dataset enabled the team to map population structures and delineate genetic boundaries among the three species.

Such distinctions are important, as they highlight populations that harbour unique genetic traits essential for adapting to specific local environments. Genomic data also helps us pinpoint coastal hotspots that should be prioritised for conservation.

Dr Tang Qian, first author.
Department of Biological Sciences
National University of Singapore, Singapore.

The study also revealed how horseshoe crabs have responded to environmental fluctuations over time. The Sunda Shelf emerged as a vital refuge for horseshoe crabs during periods of past climate change. By reconstructing the species’ evolutionary histories, the researchers found that the region has not only preserved genetic diversity but also served as a migratory corridor, which allowed populations to remain connected despite environmental changes.

Tailored conservation strategies needed

The study highlighted that future climate change poses varying levels of risk to the three species of Asian horseshoe crabs. While all are vulnerable, their ability to adapt differs. For instance, the mangrove horseshoe crab, with its limited dispersal capacity, faces higher threats of local extinction compared to the more mobile coastal and tri-spine horseshoe crabs.

Based on these findings, the researchers have proposed tailored conservation strategies to support each species in adapting to climate change:

Mangrove horseshoe crabs

• Protect and restore mangrove habitats, which are essential for the species’ survival and ability to migrate southward in response to rising temperatures.
• Prioritise the conservation of populations in the Gulf of Tonkin and South China as they face the highest evolutionary pressures from climate change.

Coastal horseshoe crabs

• Protect the Sunda Shelf region, which serves as a critical refugial habitat, particularly around the Bay of Bengal, the Malacca Strait and Southern Vietnam.
• Maintain connectivity between populations by safeguarding coastal corridors to mitigate the species’ vulnerability to habitat fragmentation.

Tri-spine horseshoe crabs

• Implement sustainable fishery regulations and restore coastal habitats, especially in areas with a history of intensive development, such as Japan, Taiwan and China.
• Focus conservation efforts on reducing human-driven threats like harvesting and habitat loss as these currently pose greater risks than climate change.

Next steps

Our study provides an important impetus and the necessary baseline data for the preservation of key habitats for horseshoe crabs’ future survival. As an important caveat, however, our work is only based on environmental factors and does not take into account future human activities that may directly alter habitats, such as coastal development. The survival of horseshoe crabs will therefore critically depend on interventions based on local contexts.

Dr Tang Qian.

Looking ahead, the researchers plan to further explore the evolutionary potential of Asian horseshoe crabs. This includes studying how specific functional genes contribute to their ability to adapt to local environments and changing climates.

We have established the Horseshoe Crab Global Biorepository, with its physical collection located at the Lee Kong Chian Natural History Museum at NUS, to support ongoing and future research. Through this resource, we hope to foster collaborations and secure funding to advance genomic research on horseshoe crabs. We are currently working with the Chinese University of Hong Kong on genomic research specifically focused on the tri-spine horseshoe crab.

Associate Professor Frank E. Rheindt.

ABSTRACT
Horseshoe crabs are unique living fossils that have remained almost unaltered through 400 million years of global change. They face rapid worldwide declines under increasing anthropogenic pressure. Using comprehensive geographic and genomic sampling combined with approaches that integrate DNA with environmental and climatic datasets, we assessed the population genetic structure, demographic histories, and vulnerability to future climate change in three out of four extant horseshoe crab species, all centered in Asia. Our study highlights that the Sunda Shelf, a complex and dynamic shallow-marine landscape, has been the sole repository of most genetic diversity among all three Asian species, and therefore crucial to the long-term survival of horseshoe crabs. Our study not only provides the first genomic baseline data for the evaluation of Asian horseshoe crabs’ conservation status but also identifies core habitats that potentially act as refugia and corridors for Asian horseshoe crab populations with impending anthropogenic global warming.

1 Introduction
Horseshoe crabs are one of the planet's foremost “living fossils”. They are known for their high morphological conservatism and a consistently slow evolutionary rate over hundreds of millions of years (Bicknell and Pates 2020). Although they are a fundamental building block of coastal marine ecosystems where they occur (Botton 2009), only four geographically restricted species remain today (Sekiguchi and Shuster 2009.1): the Atlantic horseshoe crab (Limulus polyphemus) along the Atlantic coast of the United States and the Gulf of Mexico, and three Asian horseshoe crabs, the mangrove horseshoe crab (Carcinoscorpius rotundicauda), coastal horseshoe crab (Tachypleus gigas), and tri-spine horseshoe crab (Tachypleus tridentatus), in coastal East, Southeast, and South Asia (Figure 1). Although anecdotal reports suggest declines of horseshoe crabs worldwide (John et al. 2018; Wang et al. 2020.1), important baseline population data remain scant and are mostly only available in economically advanced regions. Hence, the Atlantic horseshoe crab is more intensively studied compared with its Asian cousins (Luo et al. 2020.2), two of which (C. rotundicauda and T. gigas) are currently classified as data deficient in the IUCN Red List, whereas T. tridentatus is considered endangered.

FIGURE 1

Distribution and genetic divergence of Asian horseshoe crabs. Top left: map of the sampling localities; colored coastal lines (see legend) highlight the natural range of the three Asian horseshoe crab species; dotted lines delimit seven geographical regions (A–G) identified in genetic analysis; sampling localities are color coded according to each of the seven geographical regions. Top right: Principal component analysis (PCA) plots of horseshoe crab individuals (based on SNP dataset with 10% missing data and linked loci filtered). Colors in PCA plots correspond to colors of sampling localities on the map. Bottom: consensus population assignments (thick lines above the bar plots) and individual population assignments using ADMIXTURE (bar plots based on SNP dataset with 10% missing data and linked loci filtered) and discriminant analysis of principal components (membership assignments across SNP datasets displayed as lines under the bar plots). The consensus populations’ pairwise F_st and D_xy values (calculated based on the SNP dataset with 10% missing data and linked loci filtered) are depicted on the right of the corresponding population assignments.

The biology of all four extant horseshoe crab species has been tightly adapted to ephemeral coastline habitat and shallow-marine conditions since the late Paleozoic (Blażejowski et al. 2017; Bicknell and Pates 2020). The three Asian species’ ranges broadly overlap across the Southeast Asian Sunda Shelf, which is known as one of world's biodiversity hotspots for terrestrial (Myers et al. 2000), freshwater (He et al. 2018.1), and coastal marine (Hoeksema 2007; Schumm et al. 2019) flora and fauna. Owing to accelerated diversification rates fueled by habitat dynamics across glacial cycles, the Sunda Shelf has become a cradle of terrestrial and freshwater endemism following its first submergence at ∼400 ka (Cros et al. 2020.3; Husson et al. 2020.4; Salles et al. 2021; Sholihah et al. 2021.1; Garg et al. 2022). The region also exhibits high marine biodiversity but relatively low endemism (Costello et al. 2017.1), suggesting niche filling by dispersion (Ludt and Rocha 2015; Pinheiro et al. 2017.2), which may have turned the Sunda Shelf into a sanctuary for coastal marine biodiversity during interglacial periods.

To understand population structure, evolutionary histories, and climate change-driven vulnerability, we comprehensively sampled the three Asian horseshoe crab species across their natural range. Our results provide baseline data for conservation action geared toward the continued existence of a species group that has survived global change almost unaltered since before the age of the dinosaurs.

Far from being the 'living fossils' that 'prove evolution never happened', these four species of horseshoe crab turn out to be evidence that it has happened, driven by environmental changes that produced the present distribution and diversity, and then stabilised, resulting in a prolonged period of evolutionary equilibrium because the species were optimally adapted to their environments in warm, shallow seas with sandy beaches on which to spawn.

To anyone with the courage to lean about evolution and what causes it, which of course excludes creationists, the horseshoe crabs are not a problem for the Theory of Evolution but a vindication of it.

Refuting Creationism - How The Common Barn Swallow Shows Evolution In Progress

Hirundo rustica rustica (left) and Hirundo rustica tytleri (right) have different sexually selected traits. For example, one has a red chest and the other has a pale chest.

A pair of Hirundo rustica erythrogaster.

Credit: Matt Wilkins.

A front-row seat to evolution: What common barn swallows can teach us about how new species form | CU Boulder Today | University of Colorado Boulder

This paper in Science passed me by last December but it's too good to ignore because it is an example of something that creationists insist has never been seen because it doesn't happen - evolution in progress. And, to annoy creationists even more, it's an example of something Charles Darwin proposed as a mechanism for speciation - mate selection - as the isolating mechanism.

Barn swallows are one of the species that has formed a commensal relationship with humans that does not, like many other commensal species, involve it in consuming our crops either in the fields or in storage, from when we began building permanent or semi-permanent buildings. They are now dependent on our barns and out-houses as nesting places.

What can you tell me about the subspecies of barn swallow, Hirundo rustica, their commensal relationship with humans and their evolution into different subspecies? The barn swallow (Hirundo rustica) is a widely distributed passerine bird with several recognized subspecies that have evolved in different geographic regions. Their evolution and divergence into subspecies have been shaped by geographical isolation, ecological adaptation, and their long-standing commensal relationship with humans.

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Subspecies of the Barn Swallow (Hirundo rustica)
There are six generally recognized subspecies, each adapted to different regions:

1. H. r. rustica – Nominate subspecies
   • Breeds in Europe and Asia (west of the Urals) and winters in Africa and South Asia.
   • Characterized by a long, deeply forked tail and a reddish forehead and throat.
2. H. r. transitiva
   • Found in the Levant (Middle East, particularly Israel and Palestine).
   • Slightly darker underparts and a shorter tail compared to H. r. rustica.
3. H. r. savignii
   • Endemic to Egypt.
   • Has shorter tail streamers and a darker, more intense red coloration on the throat and forehead.
4. H. r. gutturalis
   • Breeds in East Asia (Japan, China, Korea, and parts of Russia) and winters in Southeast Asia.
   • Has a paler underbelly and slightly shorter tail than H. r. rustica.
5. H. r. tytleri
   • Breeds in central Asia (from the Altai Mountains to Mongolia and northeast China) and winters in South Asia.
   • Larger body size, darker plumage, and a more pronounced reddish throat.
6. H. r. erythrogaster
   • Found in North America, migrating to Central and South America in winter.
   • Has a deeper red or orange belly and a more robust body compared to Old World subspecies.

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Commensal Relationship with Humans
Barn swallows have one of the most well-documented commensal relationships with humans among birds. Unlike many species that avoid human settlements, barn swallows have thrived in human-altered environments, particularly in agricultural landscapes.

How They Benefit from Humans:

• Nesting Sites: They originally nested in caves and rocky outcrops but now prefer human-made structures such as barns, bridges, and eaves of houses. This shift has expanded their range and allowed for increased breeding success.
• Foraging Opportunities: Agricultural areas provide open fields where they can hunt flying insects more efficiently.
• Predator Protection: Nesting near human settlements reduces predation by natural enemies such as corvids and raptors.

Human Benefits:

• Pest Control: Barn swallows consume vast numbers of flying insects, including mosquitoes and agricultural pests, making them beneficial to farmers.
• Aesthetic and Cultural Value: Many cultures associate barn swallows with good luck and the arrival of spring.

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Evolution and Subspecies Divergence
The divergence of barn swallow subspecies is a classic example of allopatric speciation (geographical isolation) and ecological adaptation:

1. Glacial and Post-Glacial Expansion:
   • During the last Ice Age, populations were likely confined to refugia in warmer regions. As glaciers receded, they expanded into new territories, leading to genetic divergence.
2. Geographical Barriers:
   • Mountain ranges (e.g., the Himalayas), deserts, and oceans have limited gene flow between populations, leading to the formation of distinct subspecies.
3. Adaptation to Local Environments:
   • Differences in climate, insect availability, and nesting opportunities have influenced morphological and behavioral traits.
   • For example, H. r. erythrogaster in North America has evolved a more vibrant belly color, possibly due to sexual selection pressures differing from those in Europe.
4. Human Influence:
   • Their close association with human settlements has likely accelerated their spread and may have contributed to gene flow between some subspecies.

While the different subspecies show clear distinctions in plumage, size, and migratory behavior, they still interbreed where their ranges overlap, maintaining them as a single species rather than diverging into separate species.

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Conclusion
The barn swallow is a remarkable example of how a species can adapt to human presence and expand its range globally. Their subspecies have evolved due to historical climatic events, geographical isolation, and ecological pressures, yet they remain a single, highly mobile species with a complex migratory and commensal relationship with humans.

News of how they are in the process of speciating comes in the form of a paper in Science by a team led by Professor Rebecca Safran, the paper’s senior author and professor in the Department of Ecology and Evolutionary Biology at the University of Colorado Boulder, and an article in CU Boulder Today by Yvaine Ye:

A front-row seat to evolution: What common barn swallows can teach us about how new species form

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Beauty is in the eye of the beholder—even if that beholder is a barn swallow.

Depending on where the birds live, some of them may favor mates with a paler chest color while others find a redder chest more attractive. The difference in what these birds prefer when it comes to choosing a mate is helping scientists unlock one of biology’s greatest mysteries: How do new species originate?

In a new CU Boulder-led study, biologists used genetic sequencing from barn swallows around the globe to provide real-time evidence that sexual selection, in which organisms choose mates based on traits they find attractive, drives the emergence of new species.

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The study was published Dec 12 in the journal Science.

This is one of the very first papers to comprehensively show the role of mate selection decisions in the evolution of new species.

Professor Rebecca Safran, senior author
Department of Ecology and Evolutionary Biology
Colorado University Boulder
Boulder, Colorado, USA.

The new findings shed light on how new species form, a fundamental but elusive process for all life on Earth.

Proving Darwin right

Charles Darwin proposed the theory of sexual selection in 1875. It suggests that organisms evolve showy traits, like extravagant plumage or eye-catching dance moves, to attract mates. When organisms of the same species develop preferences for different traits and no longer breed with each other, new species could emerge over time, a process known as speciation.

For the past 150 years, researchers of sexual selection have primarily studied organisms that already diverged into distinct species. For example, orchids, which now encompass more than 25,000 species, originated from a common ancestor. Their remarkable diversity often leads to the assumption that they evolved different looks to attract different pollinators, said Drew Schield, the paper’s first author and assistant professor at the University of Virginia.

It’s logical to think this way and it could totally be the case, but with speciation already having occurred, it’s impossible to know for certain.

Assistant Professor Drew Schield, first author
Department of Ecology and Evolutionary Biology
University of Colorado, Boulder, CO, USA. Now at the Department of Biology
University of Virginia, Charlottesville, VA, USA.

As a result, it has been difficult to find direct evidence that sexual selection drives the emergence of new species.

Barn swallows provide a unique opportunity to explore the speciation process as it unfolds.

These birds are one of the most common and widespread species on our planet. Currently, there are six subspecies of barn swallow each looking slightly different in some traits critical to the mate choice decisions depending on where they are.

For example, the East Asian group, Hirundo rustica gutturalis, has a pale chest and shorter tail streamers—the elongated outer tail feathers. Hirundo rustica tytleri, found in Siberia, has long tail streamers and red chest feathers. The subspecies in Europe and western Asia, Hirundo rustica rustica, has a pale chest and long tail streamers.

Reuniting after isolation

Evidence suggests that the bird’s ancestors left the Nile River valley in northern Africa about 11,000 years ago and spread out across the Northern Hemisphere. For thousands of years, different populations barely interacted and developed diverse traits, forming subspecies.

Some 800 to 2000 years ago, certain subspecies expanded their territories, and habitats began to overlap. In some parts of the world, subspecies now interact with each other, producing hybrid offspring.

Safran and her team set out to investigate whether sexual selection in these birds was driving the speciation process.

The team, including Elizabeth Scordato, associate professor at the California State Polytechnic University, sequenced the genomes of 336 barn swallows from around the globe, encompassing all subspecies and three hybrid zones, where subspecies interbreed, in Eurasia.

The researchers found a dozen regions in the barn swallow genome associated with the birds’ two sexually selected traits: Ventral coloration—the plumage color of their chest and belly— and tail streamer length.

When individuals reproduce, the genes from both parents reshuffle and combine to form the genes of their offspring. When two populations encounter one another, the flow of genetic material from one to another is a marker of how similar the populations are. If the rate of gene flow is low, it means the two populations are breeding with each other at a lower rate than they would if they are the same species.

The study found that in barn swallow hybrid zones much of their genes flows freely across groups. But the genetic regions coding for ventral coloration and tail streamer length hardly transfer to other populations.

A pair of Hirundo rustica rustica in Turkey.

Credit: Matt Wilkins.

It suggests that among the hybrid individuals with parents from different subspecies, a small number of lucky birds that inherit a favorable combination of tail streamer and ventral color genes are able to attract mates. Hybrids that receive less favorable combinations tend to be less successful in reproduction.

These genes are hitting a boundary due to divergent sexual selection, and they stop moving from one population to the other.

Assistant Professor Drew Schield.

The different preferences for tail feather length and chest color across subspecies make barn swallows more likely to mate within their own group, Schield added. If the trend continues, these groups could no longer interbreed or produce offspring, markers for the formation of separate species.

Next, the team plans to sample more birds and study whether being a hybrid affects reproductive success.

It’s very cool that we could capture a real-time evolutionary portrait of this common animal and understand how and why the populations are diverging. Our understanding of the process is fundamentally important for addressing a wide range of questions related to biodiversity, evolution and conservation.

Professor Rebecca Safran.

Structured Abstract

INTRODUCTION
Assessing how sexual traits and their genetic basis contribute barriers to gene flow in secondary contact due to effects on hybrid fitness remains critical to establishing a causal role of sexual selection in in speciation. Leveraging natural systems with intraspecific variation in sexual traits at early stages of the speciation process holds promise for identifying links between patterns of phenotypic and genomic variation and the evolution of reproductive isolation.

RATIONALE
Observational and experimental studies indicate that barn swallows (Hirundo rustica) are a robust empirical model of divergent sexual selection and that the presence of multiple hybrid zones between populations in Eurasia enables investigation of barriers to gene flow. We investigate genotypic and phenotypic variation in barn swallows to (i) map the genetic basis of plumage traits used in sexual signaling, (ii) test whether loci underlying sexual traits have experienced divergent sexual selection in allopatry and present barriers to gene flow in secondary contact, and (iii) test the prediction that sexual selection has maintained linkage disequilibrium (LD) between barrier loci in secondary contact as a result of their effects on hybrid fitness.

RESULTS
We sequenced the genomes of 336 barn swallows sampled across the breeding distribution of the species and quantified variation in ventral coloration and tail streamer length, two signal traits used in mate choice. Populations differ in these traits and hybrids between the subspecies rustica, tytleri, and gutturalis exhibit phenotypes that are intermediate between or similar to parental populations. The genetic architecture of ventral color is concentrated on chromosome 1A and the Z chromosome whereas phenotypic variation is largely explained by genotypic variation at 10 loci, including the melanogenesis genes KITLG, SLC45A2, and BNC2. Variation in tail streamer length is explained by loci on chromosome 2. Sexual trait loci—ventral color loci in particular—exhibit peaks of high differentiation between populations and signatures of divergent positive selection in allopatry. We further investigated whether loci under divergent sexual selection contribute barriers to gene flow in secondary contact using geographic and genomic cline analyses across hybrid zone transects, finding that sexual trait loci constitute barriers in the rustica-tytleri and rustica-gutturalis hybrid zones whereas gene flow is less constrained across the remainder of the genome. Clines for sexual trait loci in these hybrid zones also show a high degree of concordance, consistent with selection for specific combinations of alleles from parental populations in hybrids. Finally, we tested whether selection has generated ongoing coupling of barrier loci by investigating LD patterns in hybrid zones. These tests reveal elevated LD among sexual trait barrier loci in hybrids beyond what is expected under admixture alone, consistent with the genetic coupling of barriers being an emergent property of divergent sexual selection.

CONCLUSION
Our findings demonstrate an important role for sexual selection in speciation through the analysis of the genomic basis of sexual signal traits in barn swallows, evidence for divergent selection in geographic isolation, and evidence that loci underlying traits involved in prezygotic isolation represent barriers to gene flow. Our results further support the conclusion that the genetic coupling of sexual trait loci generated by selection promotes reproductive isolation upon secondary contact.

Sexual signal traits form barriers to gene flow upon secondary contact. Barn swallows breed across nearly the entire North Hemisphere and exhibit variation in sexual signal traits across populations. Hybrid zones between these populations enable the identification of the genetic basis of sexual traits and tests of the hypothesis that divergent sexual selection promotes reproductive isolation. Genetic loci underlying sexual traits show signatures of divergent selection between allopatric populations and are barriers to gene flow in secondary contact, whereas gene flow is less constrained across the rest of the genome.

Abstract
Despite the well-known effects of sexual selection on phenotypes, links between this evolutionary process and reproductive isolation, genomic divergence, and speciation have been difficult to establish. We unravel the genetic basis of sexually selected plumage traits to investigate their effects on reproductive isolation in barn swallows. The genetic architecture of sexual traits is characterized by 12 loci on two autosomes and the Z chromosome. Sexual trait loci exhibit signatures of divergent selection in geographic isolation and barriers to gene flow in secondary contact. Linkage disequilibrium between these genes has been maintained by selection in hybrid zones beyond what would be expected under admixture alone. Our findings reveal that selection on coupled sexual trait loci promotes reproductive isolation, providing key empirical evidence for the role of sexual selection in speciation.

Schield, Drew R.; Carter, Javan K.; Scordato, Elizabeth S. C.; Levin, Iris I.; Wilkins, Matthew R.; Mueller, Sarah A.; Gompert, Zachariah; Nosil, Patrik; Wolf, Jochen B. W.; Safran, Rebecca J. (2024)
Sexual selection promotes reproductive isolation in barn swallows
Science; 386(6727) eadj8766; DOI: 10.1126/science.adj8766

Copyright: © 2024 The authors.
Published by American Association for the Advancement of Science. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

So, there we are; as good an example as any creationist would wish to ignore, of observed evolution in progress as the barn swallow diversifies into species which then become species as barriers to geneflow evolve to ensure complete genetic isolation. And an example of how, as the process of speciation progresses, interbreeding is still possible when the process is sympatric, in other words, where the two gene pools are not physically isolated. This is pretty much how human speciation occurred both in Africa and in Eurasia when Homo erectus followed by H. sapiens migrated there.

Unitelligent Design - How The Giant Clam Has a Needlessly Complex Way To Get Nutrients

Giant clams have colourful mantles.

Ruiqi Li/CU Boulder

How tiny algae shaped the evolution of giant clams | CU Boulder Today | University of Colorado Boulder

You can depend on creationism's idiot designer to never do something the obvious uncomplicated way when there is an obscure and much more complicated way to achieve the same result. It's almost exactly like it's a mindless fool, blundering about without a plan who sometimes happens across something that works and sticks with it, trying to make the best of it with more blundering.

Quite the opposite of what anyone other than a creationist would call intelligent, in fact.

For example, having designed a giant clam to live in nutrient poor coral reefs, it then designed them to have algae living symbiotically inside them, supplementing their megre diet got by filtering the seawater, with sugars manufactured by photosynthesis. This enables the giant clam to grow up to 4.5 feet (1.4 metres) in length and weigh over 700 pound (317 Kg).

Any intelligent designer could have either designed them to live in a less nutrient-poor environment or given them the chloroplasts the algae have to achieve the same result far more simply.

But of course, the giant clam wasn't intelligently designed; it evolved by the utilitarian evolutionary process that is constrained by its evolutionary history and so finds suboptimal but functional processes that a needlessly complex. This complexity impresses creationists because, not understanding how evolution works, they imagine it reflects intelligent design, instead of refuting it.

Refuting Creationism - Beetles Were Feeding on Dinosaur Feathers - 100 million Years Before 'Creation Week'

Moult remains of feather-feeding beetle larvae intimately associated with downy feather portions from an unidentified theropod dinosaur in Early Cretaceous amber of Spain. Insets show the head with powerful mandibles of one of the larval moults (top) and the pigmentation pattern of feather second order branches (bottom), with the main stem of one feather at the right of the amber fragment. The length of the amber fragment is 6 millimetres across.

Image credit: CN IGME-CSIC.

Fossils reveal a 100-million-year-old relationship between feathered dinosaurs and feather-feeding beetles | University of Oxford

Isolated moult of the feather-feeding beetle larva found in the Spanish amber outcrop of Rábago/El Soplao, with detail of its powerful mandibles (right). Length of the moult is less than two millimetres.

Image credit: CN IGME-CSIC.

To normal people, the discovery of feather-eating beetles and feather fragments in 105-million-year-old amber, 30 million years before there were birds might be a clue that something had feathers before bird had them, suggesting that birds might have evolved from whatever that was.

Not so, creationists, however. Creationists conclude that any evidence that doesn't agree with them must be wrong because their evidence-free dogma is sacred and therefore uninfluenced by real-world evidence.

So, the following is just something else for creationists to ignore while they pretend to know better than the experts who have, unlike creationists, actually studied the subject.

It is news that a study, co-led between the Geological and Mining Institute of Spain of the Spanish National Research Council (CN IGME-CSIC) and Oxford University Museum of Natural History (OUMNH) has shown that beetles fed on the feathers of dinosaurs about 105 million years ago. This is based on an analysis of spectacular fossil amber fragments, from the locality of San Just in north-eastern Spain, revealed moults of tiny beetle larvae tightly surrounded by portions of downy feathers.

The feathers belonged to an unknown theropod dinosaur that lived around 105 million years ago, during the Early Cretaceous. This means that the feathers could not have come from a ‘modern bird’ species, since current evidence indicates that this group appeared about 30 million years later in the fossil record, during the Late Cretaceous.

Refuting Creationism - How Leaf Beetles Got New Genes

The leaf beetle Spilopyra sumptuosa lives in the rainforests of eastern Australia. Its spectacular, colourful appearance is an example of the rich diversity of the large family of leaf beetles.

© Veit Grabe / Roy Kirsch,
Max Planck Institute for Chemical Ecology

Asparagus beetle, Crioceris asparagi

David Gould

Reading the genome and understanding evolution: Symbioses and gene transfer in leaf beetles

Creationists who have been fooled by the disinformation pumped out by the Discovery Institute, especially by William Dembski, believe that the only way an organism can gain new genetic information is by being given it, pre-prepared, by a magic intelligent designer, who has the magical power to assemble new DNA in just the right order and insert it into a species' genome, by a mysterious process that neither Dembski, nor one of his co-misinformers, are willing to explain.

This, of course, ignores the scientific evidence that new genetic information can be acquired by a species in several different ways, not the least of which is by horizontal gene transfer from another species, as researchers from the Max Planck Institute for Chemical Ecology in Jena, the Max Planck Institute of Biology in Tübingen, Germany, and a consortium of international scientists have just shown in respect of the leaf beetles, one of the most successful group of beetles with more than 50,000 different species worldwide.

The Malevolent Designer - How Creationism Divine Malevolence Brilliantly Designed HIV to Kill Us With

Getty Images

HZI | Decoding HIV's tactics

This should thrill devotees of creationism's intelligent designer because it exposes what a brilliant job it did in designing the human immunosuppressive virus (HIV) that causes the acquired immune deficiency syndrome (AIDS). It was discovered by a group of researchers at the Helmholtz Institute for RNA-based Infection Research (HIRI) in Würzburg and the University of Regensburg, Germany.

They have discovered how HIV hijacks the internal machinery in our cells to ensure its own survival.

Creationism in Crisis - Early Hominins in Eurasia - >1.95 Million Years Before 'Creation Week'

Cut marks on specimen from the Olteţ River Valley assemblage.

Curran, et al (2025)

Research team led by OHIO’s Sabrina Curran finds new evidence that pushes back the arrival of early hominins in Europe; discovery published in Nature Communications

Mandible with cut marks

Curran, et al (2025)

The problem with trying to maintain a belief that Earth is between 6 and 10 thousand years old is that 99.9975% of its history occurred earlier than 10,000 years ago, so almost everything archaeologists and geologists discover will prove to be from before you believe Earth existed, which, for normal people, might just be more than a hint that Earth is considerably older than you think.

Not so for creationists however, who consider their beliefs to be sacred and unfalsifiable, so the facts must be wrong.

The traditional way is to declare that radioactive decay rates on which geological formations and archaeological artifacts are dated must have changed, sometimes by many orders of magnitude.

These same creationists will also argue in a different context that the laws of nature which govern the structure and behaviour of the Universe and everything in it are so finely tuned to support life, that they must have been set by an intelligent designer.

However one of those 'fine-tuned' parameters is the weak nuclear force that binds the protons and neutrons in the atomic nuclei and for a radioactive atom to decay means that a quantum fluctuation in the energy levels in some of these particles must exceed the weak force binding them together, so the particle is ejected. But, for radioactive decay rates to be several orders of magnitude higher, the weak nuclear force would need to be much lower, below the point at which even stable atomic nuclei form at all. This means, when they believe the universe was created along with atoms, planets and life were created, there would have been no atoms to make it all from. Life would have been impossible.

An added problem is that scientists have shown that radioactive decay rates of different elements remain absolutely constant in a range of extreme temperature and pressure conditions, so there appears to be no support whatsoever for the declaration that decay rates have changed by several orders of magnitude so that an age of 10,000 year or less just happens to look like 300 million years or whatever finding is being waved aside.

If there were any merit in the creationist claim of a fine-tuned Universe, then it has been fine-tuned to make it look 14 billion years old, Earth to look nearly 4 billion years old and living organisms to have been on it for most of that time.

With that in mind then, researchers have just announced that they have found evidence of the presence of hominins in Eurasia 2 million years ago, which pushes back the earliest evidence of hominin presence outside Africa by at least 150,000 years to a time considerably earlier than Homo sapiens first appear in the fossil record - supporting the theory that the earliest migration into Eurasia was by an archaic hominin such as H. erectus.

Refuting Creationism - Walking With Dinosaurs - 166 Million Years Before 'Creation Week'

Researchers found carnivore and herbivore tracks crossing over which raises questions about whether and how the two were interacting.

Credit: University of Birmingham.

Excavated footprint.

Credit: Oxford University Museum of Natural History.

Major new footprint discoveries on Britain’s ‘dinosaur highway’ | University of Oxford

Scientists from Oxford and Birmingham Universities have uncovered hundreds of tracks of different sorts of dinosaur in a quarry in North Oxfordshire, and, unlike those in the Paluxy Riverbed, Texas, USA, no-one has carved human footprints in amongst them to fool tourists.

Amongst the tracks are five distinct trackways, the longest of which is 150 meters. Sadly for creationists, we can be sure there will not be any human footprints in the same rock formation because these tracks were made around 166 million years ago when the earliest mammals hadn't diversified even into simians, let alone the African apes.

Refuting Creationism - Our Ancesters Were Vegetarian, 3 Million Years Before 'Creation Week'

'Little Foot' from the Sterkfontein Cave, South Africa

Witwatersrand University

Three million years ago, our ancestors were vegetarian - Wits University

The Australopithecus genus is widely regarded as the immediate ancestor of the Homo genus that includes modern humans, Homo sapiens, but, from new evidence revealed by a team of researchers from the Max Planck Institute for Chemistry in Germany and the University of the Witwatersrand in South Africa, it appears that meat did not become part of our immediate ancestors' diet until after Homo species emerged.

The evidence comes from an isotope analysis of the enamel from the fossilised teeth of seven Australopithecus individuals is strongly indicative of a vegetarian diet with little or no meat consumption.

How they discovered this is the subject of a paper in Science and a new item from Witwatersrand University. Creationists should note that the isotopes of nitrogen on which this analysis is based are stable, so the traditional excuse that radioactive decay rates have changes over time is not relevant here. Besides, they are not the basis of dating these fossils, but of working out where in the food chain these Australopithecines were:

New Book - The Intelligent Design Advocate's Handbook

AI-generated image (ChatGPT4o)

Ever since teaching creationism in public schools in the USA was found to violate the Establishment Clause, by the Supreme Court in Edwards V. Aguillard (1987) the Discovery Institute has been following the "Wedge Strategy" to try to insert Christiaon fundamentalism into all aspects of American cultural, political and scientific life, using the notion of Intelligent Design as the thin end of the wedge. A campaign with the aim of nothing short of the removal of the Establishment Clause and the dismantling of Thomas Jefferson's Wall of separtion between church and state' as a precondition for establishing a Christian theocracy in the USA.

The thrust of this strategy is to try to cast doubt on the scientific validity of 'Darwinism', i.e., the Theory of Evolution, by misrepresenttion, misinformation and downright lies, to present Intelligent Design creationism as a genuine alternative scientific explanation for biodiversity, a strategy that relies on the false dichotomy fallacy that if evolution is false, creationism wins by default.

How they have been persuing this strategy is exposed in this AI-generated spoof ID advocates handbook, based on a systematic analysis and distillation of the tricks, lies and disinformation promulgated by ID advocates under the leadership of the Discovery Institute over several decade, which has become more concerted since the movement lost badly in Kitzmiller v. Dover Area School District in which ID was exposed as creationism in a lab coat. In that trial, leading ID advocate, Professor Michael J. Behe, whose views have been repudiated by his colleagues at Lehigh University Biological Science Department, was forced to admit under oath that ID is science in the same way that alchemy and astrology are science, and that:

There are no peer reviewed articles by anyone advocating for intelligent design supported by pertinent experiments or calculations which provide detailed rigorous accounts of how intelligent design of any biological system occurred.

Professor Michael J. Behe
Kitzmiller v. Dover, Day 12 Am Session

Unintelligent Design - Creationism's Designer Tries Again, and Fails, Five Times

Barbourofelis in its native Miocene habitat

AI-generated image (ChatGPT4o)

New research reveals why sabre-toothed predators evolved their deadly teeth

Creationism's designer god is nothing if not a trier - or maybe it’s just a slow learner. It tried and failed five times to create carnivores with ferocious-looking but ultimately fatal, sabre teeth.

The problem with long, curved canine teeth is that, although they are good at killing big animals quickly by tearing their throat out or stabbing them to death, because of the additional leverage on the long teeth, and the high risk of striking bone, they are prone to break, leaving their owner to starve to death.

And this has happened at least five times in evolutionary history.

The problem is there is an optimal size and shape depending in the prey species but this produces selection pressure to become more specialised in the prey which in turn produces selection pressure to produce longer, sharper teeth until the tooth shape reaches a pinnacle of shape optimised for that particular prey species. However, there is an evolutionary trade-off in that as the teeth become more specialised, the carnivore becomes more specialised and dependent on the prey species, so they are vulnerable to ecological changes that mean their prey becomes scarce of goes extinct.

How and why this occurred repeatedly due to convergent evolution is the subject of a paper in Current Biology and an open access article in The Conversation by Dr. Tahlia Pollock, Postdoctoral Research Fellow, Evans EvoMorph Laboratory, Monash University. Her article is reprinted here, reformatted for stylistic consistency:

Refuting Creationism - Ability to Perform Complex Tasks Had Already Evolved Before Chimps and Hominins Split

Male chimp cracking nuts.

Photo: Dora Biro.

Study shows that chimpanzees perform the same complex behaviours that have brought humans success | University of Oxford

Time and again, science is showing that characteristics which were once considered uniquely human, and therefore, according to creationists, evidence that humans are a special creation, distinct from all other animals, are in fact shared with other animals.

Instead of being evidence of unique creation, they are evidence of common origins and descent with modification.

On such human characteristic is the ability to perform complex tasks, involving tool use, in organised sequence, and adapt those sequences if necessary to complete the task. In other words, to plan a strategy for achieving a specific goal.

However, a new study has shown that chimpanzees also have this ability, suggesting it was present in the common ancestor before chimps and Hominins diverged some 6 million years ago.

Refuting Creationism - First Americans Were Killing Mammoths 3,000 Years Before 'Creation Week'

Clovis people hunting mammoth in Montana during the Ice Age

AI Generated (ChatGPT4o)

An artist’s reconstruction of Clovis life 13,000 years ago shows the Anzick-1 infant with his mother consuming mammoth meat near a hearth. Another individual crafts tools, including dart projectile points and atlatls. A mammoth butchery area is visible nearby. The scene is inspired by the La Prele mammoth site in Wyoming and set against the Montana landscape where the Anzick burial was discovered. Artist Eric Carlson created the scene in collaboration with archaeologists Ben Potter (UAF) and Jim Chatters (McMaster University).

Eric Carlson

Study reveals mammoth as key food source for ancient Americans | UAF news and information

A good 3,000 years before creationism's small god allegedly created the little flat planet with a dome over it described in the Bible, thinking that's what a universe looked like, human beings had migrated to North America and were hunting mammoths.

This is according to a new stable isotope analysis by a team led by researchers from the University of Alaska Fairbanks (UAF). Creationists should note that a stable isotope analysis does not depend on radioactive decay rates, so the evidence-free claim that radioactive decay rates have changed isn't open to them. Stabel isotope analysis shows us what the person's diet consisted of.

The analysis was conducted by Professor Ben Potter of the University of Alaska Fairbanks and James Chatters of McMaster University, and their colleagues. Their findings are published, open access, in the journal Science Advances and is explained in a UAF new release:

Refuting Creationism - Scientists Got The Date of the Earliest Dinosaur Wrong - It Was Even Earlier

An artist’s rendering shows how Ahvaytum bahndooiveche may have appeared in a habitat dating to around 230 million years ago.

Illustration by Gabriel Ugueto

A University of Wisconsin Geology Museum field crew is seen here in 2016 prospecting for additional material at the site in Wyoming where fossils of Ahvaytum bahndooiveche were discovered in 2013. The researchers are Aaron Kufner (left) and Jennifer Lien.

Photo by David M. Lovelace.

Dinosaurs roamed the northern hemisphere millions of years earlier than previously thought, according to new analysis of the oldest North American fossils

The thing about science that distinguishes it from religion is the willingness to change its collective mind when the facts change. This is because science is led by the fact wherever they lead

Science is reasonable uncertainty religion is unreasonable certainty. Religion appeals to those who value certainty over truth, whereas science appeals to those who value truth above certainty.

And scientists have just changed their collective minds about where and when the first dinosaurs appeared.

The consensus had been that they first appeared on the southern end of the supercontinent Pangea before it split into Gondwana in the South and Laurasia in the north and only spread to Laurasia millions of years later.

What can you tell me about the ancient reptile, Ahvaytum bahndooiveche, and its place in the evolution of dinosaurs? Ahvaytum bahndooiveche is a recently identified dinosaur species from the Late Triassic period, approximately 230 million years ago, discovered in what is now Wyoming, USA. This species is notable for being the oldest known dinosaur from the ancient northern supercontinent Laurasia, challenging previous beliefs that dinosaurs originated solely in the southern supercontinent Gondwana.

Discovery and Naming
The fossil remains of Ahvaytum bahndooiveche were uncovered in 2013 at the Garrett's Surprise locality within the Popo Agie Formation in Wyoming. The genus name "Ahvaytum" translates to "long ago," and the species name "bahndooiveche" means "water's young handsome man," a term used by the Eastern Shoshone to refer to both dinosaurs and colorful native salamanders. This naming honors the Eastern Shoshone Tribe, whose ancestral lands include the discovery site, and reflects a collaborative effort between researchers and Indigenous communities.

Physical Description
Ahvaytum bahndooiveche was a small dinosaur, estimated to be about 3 feet (0.91 meters) in length and 1 foot (0.30 meters) in height, comparable in size to a modern chicken but with a notably long tail. The fossil material includes fragmentary hindlimb bones, such as an isolated left astragalus and a partial left femur, suggesting it had progressed beyond the juvenile stage and was still slowly growing.

Evolutionary Significance
This discovery has significant implications for our understanding of dinosaur evolution. Prior to this find, it was believed that dinosaurs originated in Gondwana and later dispersed to Laurasia. The existence of Ahvaytum bahndooiveche in Laurasia during the same period as the earliest known southern dinosaurs indicates that dinosaurs were more widely distributed across the globe earlier than previously thought. This challenges the hypothesis of a delayed dinosaurian dispersal out of high-latitude Gondwana and suggests a more complex scenario for the early evolution and distribution of dinosaurs.

In summary, Ahvaytum bahndooiveche provides valuable insights into the early stages of dinosaur evolution, highlighting a broader and more rapid dispersal of these creatures across ancient Earth than was previously understood.

Refuting Creationism - Oldest-Known Evolutionary Arms Race in the Cambrian

Lapworthella fasciculata shells (under scanning electron microscope) from the Mernmerna Formation, Flinders Ranges, South Australia

R. Bicknell, et al (2025)

Oldest-Known Evolutionary “Arms Race” in the Cambrian | AMNH

Examples of Lapworthella fasciculata shells (under scanning electron microscope) from the Mernmerna Formation, Flinders Ranges, South Australia showing holes made by a perforating predator. Scale bars represent 200 micrometers.

R. Bicknell, et al (2025)

Perhaps Creationism's designer god is just a slow learner.

Anyone with an intellect greater than that of a plank should be capable of understanding the utter futility and waste in an arms race in which the strategy is to keep running faster just to stay in the same place. Arms races only make sense as the result of a game plan in which you can't communicate with your opponent and have no way of telling what he or she is thinking and if they gain the upper-hand, you lose. The only safe choice is to up the stakes - and that goes for your opponent too.

It becomes even more incomprehensible if the person you're having the arms race with is yourself, unless you're an amnesic with multiple personality disorder, and yet, if we believe creationists, that's exactly what their putative designer god is doing constantly.

Everywhere we look in nature, organisms are competing with one another for resources, or because one is trying to exploit the other as a food source in a predator-prey relationship or as a parasite trying to live in or on another organism and even killing it or making it weak and sickly as a byproduct of its parasitism. And yet creationists insist there is only one designer designing both sides in these arms races.

For some unfathomable reason, creationists like to imagine the idea of a celestial idiot having arms races with itself in millions of relationships in nature is a much better explanation than these arms races being the inevitable result of mindless evolutionary processes where a slight improvement increases the chances of leaving descendants while reducing the chance of the opponent doing the same, so creating a selection pressure for the next twist in the spiral.