Archaeopteryx: Bird or Reptile? Or Not?

(Fig. 1) The recently discovered Archaeopteryx fossil. Photo courtesy of PeerJ and the authors. Creative Commons

Archaeopteryx is arguably the most famous fossil ever discovered. It has a mixture of bird-like and reptile-like traits, and was first reported only two years after Charles Darwin published his book, The Origin of Species. Since then, another eleven Archaeopteryx specimens have been recovered from the limestones near Solnhofen, Germany. The most recent specimen was discovered in 2010 (Fig. 1), and a thorough description and comparison with other specimens was published[1] in January, 2018. One conclusion of this study is an affirmation of a previous study[2] which concluded that one of the specimens, known as the Haarlem specimen, differs from the others sufficiently to be placed in its own genus, Ostromia. Another point of note is that the various specimens of Archaeopteryx vary considerably, especially in the limb bones and dentition.

Exactly what is Archaeopteryx? Is it a bird or a reptile? For some, the presence of feathers makes it a bird, since birds are the only living group with feathers. However, living birds also have beaks and short tails, while Archaeopteryx has toothed jaws (Fig. 2) and a long bony tail like reptiles (Fig. 1).

The skull and mandibles of the most recently discovered specimen of Archaeopteryx (see Fig. 1), showing dentition (to the left of the picture). Scale bar is 1 cm long. Photo courtesy of PeerJ and the authors. Creative Commons

The problem of classifying Archaeopteryx can also be seen in the scientific literature. According to the Encyclopedia Britannica,[3] Archaeopteryx is a “genus of feathered dinosaur that was once thought to be the oldest known fossil bird.” Another source[4] states “It has long been accepted that Archaeopteryx was a transitional form between birds and reptiles, and that it is the earliest known bird.” So why are there different opinions and why does it matter?

There are different opinions about the classification of Archaeopteryx because it does not fit with either birds or reptiles as we know them today. It is like a mosaic, with a mixture of traits not found in any living species. In recent years, several other fossils have been found with features that are a mosaic of avian and reptilian traits, so that Archaeopteryx is no longer as unique as was formerly thought. If one uses the definitions of “bird” and “reptile” based on living species, one would conclude that Archaeopteryx is neither a bird nor a reptile, but belongs in a category of its own. But this answer has not been generally regarded as satisfactory.

Classification of Archaeopteryx matters to evolutionists because evolutionary theory demands common ancestry via a series of evolutionary transitions, and Archaeopteryx seems to be the best available candidate for a reptilian ancestor of birds. Discovery of several other fossils with a mosaic of avian and reptilian traits complicates the issue, so that Archaeopteryx can be considered a feathered dinosaur without abandoning the idea that dinosaurs were ancestors of birds. This is at least part of the reason why the classification of Archaeopteryx is important to evolutionists. But why should it be important to creationists?

Creationists are interested in how Archaeopteryx is classified because they are interested in the creation, and because evolutionists present this fossil as a putative example of an evolutionary transition. How might a creationist interpret this enigmatic fossil? Some creationists have concluded[5] that Archaeopteryx is a bird, but this is not the only answer a creationist might give. There are at least two other answers a creationist might give to the question “Is Archaeopteryx a bird or a reptile?” The first possible answer is “No,” while the second possible answer might be “Yes,” – it is both.

The first answer, “No,” implies that Archaeopteryx is neither a “bird” nor a “reptile” but a different kind of animal. To understand this better, consider what a creationist means by “bird.” Is “bird” a single, natural category containing only one kind of created animal, or is it a collective, artificial category used to refer to a large number of separately created animals that happen to have similar body designs that include feathers, beaks, and short tails, among other things? We use the term “bird” to refer to animals as different as ostriches, hummingbirds, ducks, owls and sparrows. Are these all one created kind of animal, or do they represent several similar but separately created types? Creationists would surely favor the second alternative: “bird” is an artificial collective term referring to many separately created types of animals with a similar design. There is no need to try to force Archaeopteryx into a preexisting category – it could just as well be considered a separate type of animal and given its own category name.

The second possible answer to the above question, “Yes” implies that Archaeopteryx is both a bird and a reptile. This might imply that Archaeopteryx could be an example of the “corruption” of all animals mentioned in Genesis 6:1-13. God is quoted in this text as stating that the corruption of nature was one of the reasons for destruction of the world by a flood. Perhaps the “corruption” of nature included the combining features from different parts of the creation into unnatural species, of which Archaeopteryx may have been an example.

Archaeopteryx and its interpretation raise some interesting philosophical questions for creationists. Is it necessary that all fossils fit into existing categories based on living species? Are categories based on living species natural categories or are they artificial categories for a group of separately created species? Are all species more-or-less exactly as they were created, or has the creation been subject to considerable change and corruption? Regardless of which alternative is preferred, creation theory provides a robust framework for explaining the general lack of fossils that could be considered evolutionary transitions, and also provides potential explanations for the few such fossils that have been found, including Archaeopteryx.

[1] Rauhut et al. (2018) The oldest Archaeopteryx (Theropoda: Avialiae); a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ 6:e4191; DOI 10.7717/peerj.4191

[2] Foth, C and OWM Rauhut, Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology (2017)17:336. 

[3] accessed 20 Feb 2018.

[4] accessed 20 Feb 2018.

[5] accessed 20 Feb 2018.

by Jim Gibson, PhD
Director of the Geoscience Research Institute