Fossils reveal a 100-million-year-old relationship between feathered dinosaurs and feather-feeding beetles | University of Oxford
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.
What information do you have on feathered theropod dinosaurs from 105 million years ago? Feathered theropod dinosaurs from around 105 million years ago (during the Early Cretaceous) are well-documented through fossils primarily found in regions like China, North America, and Europe. Here's a summary of key information:The researchers have published their findings, open access, in Proceedings of the National Academy of Sciences of the United States of America (PNAS) and explained it in a new released by Oxford University:
- Examples of Feathered Theropods
- Beipiaosaurus: Found in China, this therizinosaur was covered in a downy coat of feathers and is notable for its herbivorous diet despite being a theropod.
- Sinornithosaurus: A dromaeosaurid (related to Velociraptor), it had long feathers and was likely a skilled climber or glider.
- Microraptor: A small, four-winged dromaeosaurid with long feathers on both its arms and legs, it provides strong evidence of gliding or primitive flight.
- Yutyrannus: A large, feathered tyrannosauroid from China, showing that even larger theropods had feathers for insulation or display.
- Feather Functions
- Insulation: Feathers helped regulate body temperature, especially in smaller theropods.
- Display: Brightly coloured or patterned feathers could have been used for mating displays or species recognition.
- Flight/Gliding: Some theropods, like Microraptor, had feathers adapted for gliding or powered flight.
- Camouflage: Feathers may have helped some species blend into their environments.
- Fossil Evidence
The most significant fossil discoveries come from the Jehol Biota in northeastern China, which includes exquisitely preserved specimens showing feather impressions. This region provides a detailed glimpse into the diversity of feathered theropods.- Evolutionary Significance
Feathered theropods are pivotal in understanding the evolution of birds. By 105 million years ago, many theropods had bird-like features, including:
These traits bridge the gap between non-avian dinosaurs and early birds like Archaeopteryx (though Archaeopteryx lived earlier, in the Late Jurassic).
- Hollow bones.
- Reduced tails.
- Advanced feathers similar to modern birds.
- Ecosystem
Feathered theropods from this period lived in diverse ecosystems with lakes, forests, and volcanic landscapes. They coexisted with a variety of plants, fish, amphibians, and other dinosaurs, including early ceratopsians and sauropods.
Fossils reveal a 100-million-year-old relationship between feathered dinosaurs and feather-feeding beetles
New fossils in amber reveal that beetles fed on the feathers of dinosaurs about 105 million years ago. The exquisite specimens show one of the best supported examples of a close interaction between vertebrates and arthropods in the fossil record. The study has been published in Proceedings of the National Academy of Sciences of the United States of America.
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.
The larval moults preserved in the amber were identified as related to modern skin beetles, or dermestids. Dermestid beetles are infamous pests of stored products or dried museum collections, feeding on organic materials that are hard for other organisms to digest such as natural fibres. However, dermestids also play a key role in recycling organic matter in the natural environment, and often inhabit the nests of birds and mammals, where feathers, hair, or skin, accumulate.
The feathers had almost certainly become detached from the host dinosaur, since they showed signs of damage and decay, including fungal strands growing on their surface. Consequently, the researchers propose that the beetle larvae probably lived in or on a dinosaur nest, where enough feathers could accumulate to sustain a population. This nest would have been on or close to a resin-producing tree, with the first step leading to the formation of the amber fossils happening when a flow of resin trapped the larvae and feathers, preserving them together for millions of years.
Similarly, modern bird and mammal nests are inhabited by diverse communities of insects and arachnids that feed on the rich –yet often highly specialised– sources of organic material, which include keratin in the form of feathers, hair, and skin, as well as faeces.
It is unclear whether the feathered theropod host benefitted from the beetle larvae feeding on its detached feathers in this plausible nest setting, however, the theropod was most likely unharmed by the activity of the larvae since our data indicate that these did not feed on "living" plumage. Furthermore, the larvae lacked defensive, bristle-like structures which among modern dermestids can irritate the skin of nest hosts, even killing them.
The fossils puzzled us for a while, since they show some features that do not fall among the modern diversity of skin beetles. Fortunately, working at OUMNH gives me access to one of the best entomological libraries in the world and more than five million pinned insect specimens in its collections, which can be used to match against fossils. I’m incredibly lucky to work with such privileged assets.
Dr Ricardo Pérez-de la Fuente, co-lead author
Oxford University Museum of Natural History (OUMNH).
Dr Pérez-de la Fuente’s research focuses on preservation in amber and fossil arthropods, particularly insects and arachnids dating from the Cretaceous. In this new research, his contribution included identifying the fossil insect species captured in the amber fragments.
Vertebrates and arthropods have coexisted for more than 500 million years, and their interactions throughout deep time are thought to have critically shaped their evolutionary history, often leading to coevolution. In modern ecosystems, examples of these diverse and complex ecological relationships include ticks infesting cattle, frogs capturing insects with acrobatic tongues, and barnacles growing on the skin of whales. Nevertheless, direct evidence of arthropod-vertebrate relationships is extremely rare in the fossil record. The only previous instances had been of parasites, either chewing lice or blood-sucking ticks. But in this new study, the researchers believe that the theropod dinosaur was either unharmed by the beetles or may even have benefitted from the cleaning effect of the beetle feeding on its detached feathers.
The emerging view is that some groups of arthropod symbionts of feathered theropods in the late Mesozoic transitioned to modern birds in the Cenozoic, Earth's current geological era. I suspect that as more fossils are unearthed we will keep finding more key evidence on how two of the most prominent groups of animals, arthropods and vertebrates, have influenced each other’s fascinating, and often intertwined, evolutionary pathways.
Our findings demonstrate that beetles and feathered theropods have interacted since the Mesozoic, and shed light on the evolutionary importance of early relationships between arthropods and vertebrates.
Dr Ricardo Pérez-de la Fuente.
The paper ‘Symbiosis between Cretaceous dinosaurs and feather-feeding beetles’ has been published in the journal Proceedings of the National Academy of Sciences of the United States of America.
The study was 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).
SignificanceFeathers, like hair, are integumentary structures composed of tough, durable keratin. Despite being a concentrated source of this protein, few groups of arthropods have evolved adaptations to ingest and metabolize keratin (keratophagy) (1, 2). Aside from its ecological significance, keratophagy is important from an evolutionary standpoint as well, representing, for example, a transitional stage between free-living bark lice (Psocodea) and true parasitic lice (Phthiraptera), in the form of scavenging book lice (genus Liposcelis) that commonly feed on nest debris, including keratin (1). Keratophagy as a trophic specialization entails a parasitic symbiosis if the feeding arthropod guest causes damage in the integument of the vertebrate host (3). On the contrary, keratophagy can also involve a commensal–mutualistic symbiosis between the host and the arthropod consuming the host’s shed, accumulated integumentary structures, possibly advantageous to the host by cleaning its nest (4). In any case, symbiotic interactions (used herein in the wide sense) often do not fit into one of the traditional categories (3). Behaviors involving keratophagy do not necessarily represent trophic specializations, such as reptiles eating shed skins from themselves or conspecifics (5).
Vertebrates and arthropods are two of the most successful and frequently fossilized animal groups, but direct evidence of their interaction in deep time – entailing the joint, intimate fossilization of remains from both groups – is extremely rare. Our discoveries in fossilized plant resin (amber) from the Early Cretaceous of Spain show that a symbiotic relationship, likely commensal/mutualistic, was established between beetle larvae feeding on detached feathers and feathered dinosaurs (theropods) more than a hundred million years ago. Only two previous records of arthropod–theropod symbiosis involving direct fossil evidence were known, both parasitic. Our findings demonstrate that beetles and feathered theropods have interacted since the Mesozoic, and shed light on the evolutionary importance of early symbiotic relationships between arthropods and vertebrates.
Abstract
Extant terrestrial vertebrates, including birds, have a panoply of symbiotic relationships with many insects and arachnids, such as parasitism or mutualism. Yet, identifying arthropod–vertebrate symbioses in the fossil record has been based largely on indirect evidence; findings of direct association between arthropod guests and dinosaur host remains are exceedingly scarce. Here, we present direct and indirect evidence demonstrating that beetle larvae fed on feathers from an undetermined theropod host (avian or nonavian) 105 million y ago. An exceptional amber assemblage is reported of larval molts (exuviae) intimately associated with plumulaceous feather and other remains, as well as three additional amber pieces preserving isolated conspecific exuviae. Samples were found in the roughly coeval Spanish amber deposits of El Soplao, San Just, and Peñacerrada I. Integration of the morphological, systematic, and taphonomic data shows that the beetle larval exuviae, belonging to three developmental stages, are most consistent with skin/hide beetles (family Dermestidae), an ecologically important group with extant keratophagous species that commonly inhabit bird and mammal nests. These findings show that a symbiotic relationship involving keratophagy comparable to that of beetles and birds in current ecosystems existed between their Early Cretaceous relatives.
The plumage of diverse theropods has been well characterized in finely preserved Mesozoic compression fossils (6, 7). In Cretaceous amber, theropods are much less diverse, but the feathers are preserved in unmatched detail (8–13). In contrast, the only definitive keratophagous arthropod hitherto identified in the fossil record is a chewing louse (Amblycera) of the family Menoponidae, preserved as a compression fossil from the Eocene of the German outcrop of Messel; the remains of feather barbules preserved in its gut are direct evidence of keratophagy (14). Moreover, only a few Mesozoic (15, 16) and Cenozoic (17–20) amber records are known to contain arthropods associated with remains of the vertebrate host (feathers and hair), indicating symbiotic relationships. These Mesozoic amber records represent direct evidence of an arthropod–dinosaur symbiotic relationship, all entailing instances of ectoparasitism (15, 16). A few Mesozoic records of arthropods associated with remains of the vertebrate host also exist in compression strata (21, 22); yet due to preservational and taphonomic limitations in lithological matrix, the interpretation of these assemblages is usually ambiguous.
A recent, controversial report involves minute, wingless insects preserved adjacent to feathers in Burmese amber, reported as keratophagous ectoparasites, and placed in a new family, Mesophthiridae (23). Reassessment of the morphology, however, indicated that these are actually early instars (crawlers) of scale insects (Coccoidea), a group that today is wholly phytophagous, siphoning plant vascular fluids using long, very fine stylets (24). These stylets are coiled internally when at rest, forming a very distinctive structure called the crumena, which is clearly visible in the images from the original report along with other features diagnostic of coccoids. It was proposed that these fossil coccoids may have been merely phoretic, but they definitely were not feeding on the feathers (24, 25), despite some feather portions with apparent feeding damage, probably produced by other arthropods. In a rebuttal by the original authors, new images still did not resolve the putative chewing mandibles (26). The morphological evidence is unequivocal that Mesophthiridae are coccoids and thus could not have been keratophagous.
Here, we present assorted evidence of keratophagy involving beetle and feather remains preserved in Cretaceous amber from Spain, representing a rare instance of arthropod–dinosaur symbiotic relationship in deep time.E. Peñalver, D. Peris, S. Álvarez-Parra, D.A. Grimaldi, A. Arillo, L. Chiappe, X. Delclòs, L. Alcalá, J.L. Sanz, M.M. Solórzano-Kraemer, R. Pérez-de la Fuente
Symbiosis between Cretaceous dinosaurs and feather-feeding beetles Proc. Natl. Acad. Sci. U.S.A. 120 (17) e2217872120, DOI: 10.1073/pnas.2217872120 (2023).
Copyright: © 2023 The authors.
Published by the National Academy of Sciences of the USA. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
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