Complexity First: Comb Jellies Upset Evolutionary Expectations
The empirical trajectory across
the rock record is the reverse
of Darwinian expectation
Comb Jellies: The Cladistic Nightmare at the Root of the Animal Tree
by John Wise, PhD
Ctenophores Aren’t Just Beautiful. They’re Biological Wonders (Quanta Magazine, 16 September 2026). Please, read this Quanta Magazine article and look at its graphics. It is worth your time.
Watch a living comb jelly pulse through the dark waters of the ocean depths, and you will see why marine biologists are captivated. I was. I strongly encourage you to read this article and see its pictures/movies. Propelled by eight iridescent rows of beating cilia that scatter light into shimmering rainbows, these creatures are mesmerizing, almost otherworldly. They can even reverse their developmental clock like a marine Benjamin Button (the article’s figure, not mine), reverting from adult to larva; some can withstand crushing deep-sea pressures thanks to specialized cone-shaped lipids called plasmalogens, keeping cell membranes pliable enough for nerves to fire beneath miles of ocean water.
The real shock-wave that ctenophores (“TEEN-uh-fors”) are sending through the biological world is not aesthetic, however. It is revolutionary.
These jelly-like marine predators shatter the neat orderly staircase evolutionary biology built to explain animal origins. Instead of serving as a modest rung near the bottom of animal life, ctenophores are upending the foundational dogmas of cladistics and the textbook story of simple-to-complex descent. Although new to me, the ctenophore-sister hypothesis has been a frequent guest here at CEH: here, here, here, here and making its debut in 2013.
Demoting the Sponges
Comb jellies (Ctenophora) are very complex animals to have appeared abruptly. (DFC)
For more than a century, evolutionary textbooks presented a clean, plausible progression for the dawn of animal life. First came single-celled protozoans. Then came loose colonies. Then came the sponges (Porifera), the ideal evolutionary starter kit: sessile (fixed in place) filter feeders lacking true tissues, a digestive tract, muscles and nerves. From this economy-model baseline, nature is supposed to have gradually accreted complexity: first radial animals with simple, diffuse nerve nets (like true jellyfish and sea anemones), followed by bilateral creatures with centralized brains, muscles, and complex organs.
That “storied” progression has been upset by comb jellies. Over the last two decades, molecular phylogenetics has repeatedly revived the Ctenophora-sister hypothesis, and a 2023 chromosome-level synteny study provided unusually strong support for it.
In cladistics, calling one lineage the “sister group” to another means they share an immediate common ancestor that no other group possesses. If sponges are the sister group to all other animals, the evolutionary staircase holds: a tidy ascent from simple to complex. But if ctenophores are the sister group to all other animals, the root of the animal tree is already an amazingly complex metazoan, possessing organized digestive tracts with anal pores, smooth muscle fibers, sophisticated sensory organs that detect gravity and light, and an elaborate nervous system.
Pawel Burkhardt, an evolutionary biologist at the University of Bergen, admitted the obvious to Quanta:
“If you think about the earliest branching animal lineage, you would expect less complexity. That changes a lot of the assumptions [about] how the very first animal may have looked.”
Perhaps the understatement of the decade.
Placing ctenophores at the base of the animal tree confronts evolutionary theory with a dilemma: either A) ctenophores are the sister, and this common ancestor of all animals already possessed muscles, gut canals, and a nervous system; in this case sponges must have suffered catastrophic evolutionary loss, throwing away their nerves, discarding their muscles and their guts, and devolving into sessile filter feeders. Or B) Sponges are the sister and nature had to invent nervous systems, gut structures, and muscle tissue twice … independently … from scratch, using entirely separate cellular architectures and biochemical toolkits to arrive at the same functional designs.
Former senior paleontologist at the State Museum of Natural History in Stuttgart, Günter Bechly, and Discovery Institute geologist Casey Luskin have both analyzed how these anomalies expose the vulnerability of cladistic methodology. As Luskin noted in June 2015 when early ctenophore genomic data began shaking up the establishment:
“Evolutionary systematics assumes that common ancestry is true and therefore all organisms belong within a nested hierarchy, and then it uses methods to force-fit any organism into the tree, even if that organism has traits that don’t fit neatly within the tree… This is exactly what happened after the comb jelly genome was sequenced… This means that either complex muscle and nervous cells were lost in sponges (even though these are complex, useful traits you’d probably want to keep around) or muscles and brains evolved convergently in later animals. Either way, you’re left with a situation where comb jellies don’t fit neatly into the animal tree. They show a mosaic of traits that shouldn’t be the case under common descent.”
The Nerve Net That Isn’t Like Ours
The evolutionary headache deepens when one examines the ctenophore nervous system.
In every other animal with nerves, from anemones to humans, neuronal cells communicate across physical gaps called synapses, using chemical neurotransmitters to bridge the divide. Ctenophores, however, possess what is called a syncytial nerve net.
In a syncytium, individual cells fuse together into a single continuous web of shared cytoplasm. There are no synapses between the cells of this net; the electrical and chemical signals travel through an unbroken, communal cellular bridge. It is an entirely distinct, sophisticated way of engineering neural transmission.
Because the molecular machinery powering this net differs fundamentally from standard bilaterian neurobiology (like ours), researchers are forced to argue that the nervous system must have evolved multiple times independently. What is supposed to be the rarest, most intricate evolutionary milestone in the history of life suddenly had to happen in parallel, by chance, without leaving a trace of its evolutionary precursors, and at the base of the tree from which it is supposed to have evolved.
The 180-Million-Year Phantom in the Cryogenian
To make the ctenophore-first cladogram work, molecular biologists cannot simply point to the Cambrian rocks where comb jellies appear. They must push the clock back.
Way back.
In 2023, researchers leaned on chromosome synteny, the study of whether sets of genes remain linked together on the same chromosomes across different species over deep time, to assert that ctenophores diverged approximately 700 million years ago.[1] That secular date drops the lineage squarely into the Cryogenian Period (720 to 635 million years ago), the secular age of “Snowball Earth,” characterized by massive, catastrophic global glaciations.
What does the fossil record yield from the Cryogenian? The empirical record contains single-celled organic cysts, likely algae, microscopic vase-shaped microfossils (testate amoebae), bacterial mats and stromatolites. What is missing is one unambiguous trace of an animal. There are no comb rows, no gravity-sensing aboral[2] organs, no gut canals, and no animal bodies whatsoever.
By demanding a divergence date of 700 million years ago, evolutionary cladists must conjure a 180-million-year “ghost lineage,” a temporal gulf between their models and the fossil appearance of fully-formed ctenophores in the Early Cambrian (~520 million Darwin years ago). We are asked to believe that complex animals equipped with muscles, nerve-nets, and digestive systems swam in Neoproterozoic seas for nearly two hundred million years without leaving behind a single identifiable body fossil. What’s a good Darwinist to do?
Reach for a classic rescue device: the “artifact hypothesis.”
But that excuse, Bechly points out in his essay “The Demise of the Artifact Hypothesis,” has passed its expiration date:
Where are the proposed thousands of intermediate forms that led to Cambrian animals like trilobites? Evolutionists were dumbfounded by the silence in the fossil record and had to come up with a ready explanation for this conflicting evidence. The most popular attempt to resolve this discrepancy is the so-called “artifact hypothesis,” which proposes that the Cambrian animal phyla had ancestors, but that those ancestors either left no fossil record or have not yet been found, because of the incompleteness of the fossil record.
But …
[quoting Daley et al. (2018)] “Modes of fossil preservation are comparable in the Cambrian and Precambrian”…
Therefore …
We can conclude that the artifact hypothesis, which was nothing but an ad hoc strategy to get rid of conflicting evidence, can finally be put to rest for good. The absence of … fossils of putative precursors of the Cambrian animal phyla is not an artifact of undersampling or an artifact of taphonomy… the Cambrian explosion has turned out to be even more abrupt than was previously thought. If a problem does not dissolve with increasing knowledge but only gets worse over time, it is a good indicator that this problem is very real. Darwinists have to face the fact that a core prediction of their theory miserably failed an important empirical test.
If the rocks can preserve microscopic, single-celled algal cysts and delicate soft-bodied microbial mats across the late Precambrian, they can preserve a comb jelly. The absence of fossils is not a failure of preservation; it is a failure of the theory.
The Real Cambrian Fossils: Complexity First, Loss Later
Living ctenophores have 8 comb rows. Some fossils have 24 comb rows plus protective armor. (Marco Fasse, Creative Commons)
When undisputed ctenophores finally burst into the fossil record during the Early Cambrian (preserved in Lagerstätten like the Burgess Shale in Canada), they challenge the Darwinian narrative. They did not enter as primitive, half-formed prototypes waiting to evolve complexity. If anything, early Cambrian ctenophores were more complex than modern ones, having skeletal armor, higher comb counts,[3] and some even had (what appear to be) longitudinal nerve tracts rather than merely the diffuse syncytial nerve net seen in living forms.
The empirical trajectory across the rock record is the reverse of Darwinian expectation: sudden structural disparity appears first, followed by morphological reduction, organ loss, and long-term stasis. But the comb jelly is what it has always been: a breathtaking masterpiece of integrated, biological design whose form fits its functions.
What doesn’t fit is the cladistic staircase. The evidence stubbornly refuses to climb it.
Footnotes
[1] Schultz, D.T., Haddock, S.H.D., Bredeson, J.V. et al. Ancient gene linkages support ctenophores as sister to other animals. Nature 618 (17 May 2023), 110–117 (2023). https://doi.org/10.1038/s41586-023-05936-6
[2] This is a great job if you want to expand your scientific vocabulary. In radial symmetry (as opposed to bilaterian symmetry like us), “aboral” refers to the opposite end from the mouth. In comb jellies the aboral organ is part of what makes it so striking:
Using volume electron microscopy, Burkhardt’s lab identified 17 unique cell types in Mnemiopsis leidyi — 11 of which were previously unknown — in an all-important structure called the aboral organ (center). Together, these cells help ctenophores sense light, pressure, and gravity, and the aboral organ is tightly integrated with a continuous network of fused neurons that forms the nervous system. “Having more neurons condensed at a certain place, that’s one theory [for] how the very first brains evolved,” Burkhardt said.
[3] Living comb jellies have eight comb rows. Their Cambrian predecessors sported 16 or even 24 comb rows, along with protective cap-plates, intricate internal valving and complex internal tissue flaps likely used to control water flow or manipulate trapped prey.
John Wise received his PhD in philosophy from the University of CA, Irvine in 2004. His dissertation was titled Sartre’s Phenomenological Ontology and the German Idealist Tradition. His area of specialization is 19th to early 20th century continental philosophy.
He tells the story of his 25-year odyssey from atheism to Christianity in the book, Through the Looking Glass: The Imploding of an Atheist Professor’s Worldview (available on Amazon). Since his return to Christ, his research interests include developing a Christian (YEC) philosophy of science and the integration of all human knowledge with God’s word.
He has taught philosophy for the University of CA, Irvine, East Stroudsburg University of PA, Grand Canyon University, American Intercontinental University, and Ashford University. He currently teaches online for the University of Arizona, Global Campus, and is a member of the Heterodox Academy. He and his wife Jenny are known online as The Christian Atheist with a podcast of that name, in addition to a YouTube channel: John and Jenny Wise.