Trilobite Ocelli Found; Like Compound Eyes, They Popped Into Existence

The so-called median eyes of many arthropods were thought
to be missing in trilobites, but have now been discovered

Many arthropods, including insects and spiders, have “median eyes” or ocelli in the middle of their foreheads. In flying insects such as dragonflies, these ocelli serve as sensors of optic flow, the motion of objects at the sides of the field of vision as the animal moves forward. Optic flow is an important datum in navigation, indicating speed and direction (think of the star fields in movies like Star Wars at the jump to light speed).

Evolutionists had an argument that ocelli emerged by natural selection on the grounds that some of the earliest arthropods, like trilobites, lacked them. That argument has now been disproved. Trilobites had median eyes after all, and more than many modern arthropods have.

Inspired by the compound eyes of a species of trilobite, researchers at NIST developed a metalens that can simultaneously image objects both near and far. This illustration shows the structure of the lens of an extinct trilobite. Credit: NIST

New eyes discovered in trilobites (Science Daily, 20 March 2023). Researchers at the University of Cologne took a closer look at fossil trilobites and found evidence of median eyes. They had not been discovered earlier, because they apparently developed in larval stages and were hidden under the carapace in adults. Here’s what the press release says:

A dragonfly’s compound eye can have up to 30,000 facets. The head also has an organ for measuring optic flow called the ocellus (organ between the compound eyes).

Trilobites, prehistoric sea creatures, had so-called median eyes, single eyes on their foreheads, in addition to their compound eyes, research conducted by Dr Brigitte Schoenemann at the University of Cologne’s Institute of Zoology and Professor Dr Euan Clarkson at the University of Edinburgh has now found out. Such single eyes are found in all arthropods and also in many relatives of the extinct trilobites. They are usually small cup eyes (ocelli), sometimes even equipped with lenses, and not unlike human eyes. These so-called median eyes are typical for all arthropods, but had not yet been discovered in trilobites despite 150 years of research.

The researchers explain why they were not found till now:

The scientists assume that these eyes were characteristic of the larval stage of the animals. The single eyes were located under a transparent layer of the carapace, which became opaque during the fossilization process. Both circumstances contributed to the ocelli not being discovered until now. The researchers also detected median eyes in other, approximately 500-million-year-old arthropods.

This means that Darwinians cannot claim that ocelli were novel features that emerged at some point but did not exist in the ancestors of modern arthropods. No; they were already there in trilobites that date back to the Cambrian Explosion: the fossil layer where 18 to 20 body plans appear suddenly, fully formed.

Looks simple till you look into the details.

A New Just-So Story

In their paper in Nature Scientific Reports dated 8 March 2023, Schoenemann and Clarkson want to retain a Darwinian narrative about the origin of eyes. In “The Median Eyes of Trilobites,” they admit that they “document median eyes in trilobites the first time.” But then they try to put the pieces into a phylogenetic story of ancestry and descent, where in Darwinspeak, simple things are called “primordial” or “original” and advanced things are called “derived.” To make the story work, they have to raise the perhapsimaybecouldness index.

Here we give an overview of the occurence of median eyes in the arthropod realm and their phylogenetic relationship to other ocellar eye-systems among invertebrates. We discuss median eyes as represented in the fossil record e.g. in arthropods of the Cambrian fauna, and document median eyes in trilobites the first time. We make clear that ocellar systems, homologue to median eyes and possibly their predecessors are the primordial visual system, and that the compound eyes evolved later. Furthermore, the original number of median eyes is two, as retained in chelicerates. Four, probably the consequence of a gene-dublication, can be found for example in basal crustaceans, three is a derived number by fusion of the central median eyes and characterises Mandibulata. Median eyes are present in larval trilobites, but lying below a probably thin, translucent cuticle, as described here, which explains why they have hitherto escaped detection. So this article gives a review about the complexity of representation and evolution of median eyes among arthropods, and fills the gap of missing median eyes in trilobites. Thus now the number of median eyes represented in an arthropod is an important tool to find its position in the phylogenetic tree.

This is highly misleading. The finding does not fill a gap; it erases a gap. The median eyes were already there!

The authors clearly accept the Popeye Theory of Evolution: eyes pop into existence by chance (they “appear”), suddenly and fully functional. Watch the hedging words.

In total it seems that the first visual systems that equipped panarthropods were ocelli (see lobopodians), then compound eyes appeared. Ocelli, retained as median eyes, kept on co-existing with compound eyes during the course of evolution.

I’m Popeye the Darwin man; I fantasize germs to man. I fight to the finish To ID diminish; I’m Popeye the Darwin man.

Do they show a slow-and-gradual morphing of ocelli into compound eyes, as required by their tale? No. The quote above says that they “appeared.” Another synonym for the Popeye Theory is that they “developed.” But if there is no record of gradual change from one type to the other, the story is equivalent to a miracle. Remember, too, that eyes are not useful unless connected to brains that know how to use them.

Each phylum of animals seen in the Cambrian Explosion had eyes or sensory organs appropriate to its lifestyle needs. One cannot trace a lineage from one phylum like worms (Annelida) to another like arthropods, because those phyla went their separate ways. But that is the story they try to tell, mixing in some Darwin Flubber with Convergence. Onychophorans are not Arthropods.

Annelids show a concentration of light receptors in the head area, but the further development of more complex light-sensing organs is convergent to the panarthopoda.

Thus in total one can observe a consistent phylogenetic lineage of the ocellar median eyes from the ocelli of onychophorans to the median eyes of euarthropods. Although the segmental composition and evolutionary development of the arthropod brain is complex and not yet understood completely, the innervation of the ocelli is provided by corresponding parts of the brains. It is always from the anterior part of the protocerebrum, respectively by corresponding homologous parts of the central ganglia, while compound eyes always are innervated by laterally and posteriorly positioned nerves.

All this says is that median eyes and compound eyes connect to different parts of the brain. That is not evolution. Where is the chain of random mutations that were somehow selected by the Stuff Happens Law to form a compound eye from a median eye, and rewire it to a different part of the brain? It doesn’t matter that different branches of the arthropod phylum have different numbers of median eyes, or that non-arthropods had median eyes. Trilobites had median eyes and compound eyes. How did that happen?

Compound eye typical of insects.

Compound eyes are not simple; they have lenses, pigments and photoreceptor cells. The individual facets in a compound eye are then fused by the brain into a mosaic image, presenting a camera-like image of the surroundings. Visual systems are irreducibly complex. They do not just “appear” or pop into existence. These median eyes, “not unlike human eyes,” now are seen to have been there all along after 150 years of studying trilobites. The discovery of ocelli in trilobites exacerbates Darwin’s challenge of explaining “organs of extreme perfection” like eyes. As these authors had to admit, “from the very beginning of their appearance in the fossil record they were equipped with very elaborate compound eyes.”

Update 21 March 2023: Live Science gives its take on this finding. For most of the article, reporter Jennifer Nalewicki sticks to the facts. In the last paragraph, she enters her Darwin trance and begins speculating:

At different points in evolution, trilobites likely had anywhere from one to multiple median eyes. For example, the researchers found that the trilobite Cyclopyge sibilla had three median eyes equipped with lenses similar to those in human eyes, and Cindarella eucalla had four. Nowadays, most modern insects and crustaceans have three median eyes, according to the statement.

But surely the challenge for evolution is in getting one median eye, not two, three or four. Is she promoting the Popeye Theory unaware? At the end, she uncritically quotes the Darwinian researchers, who said, “We now have an important tool to determine [trilobites’] position in the evolutionary tree.”

It’s hard to blame Jennifer who, like students around the world, was raised on a steady diet of Darwinism without any exposure to the flaws and weaknesses. The Darwin Party Storytelling Empire taught her well: when you don’t understand something, just Darwinize it and Big Science will accept you. They will not censor you. Raised to think this way, she automatically assigns any change to Darwinism. What else is there? She looks in her toolkit and doesn’t find anything else. Eyes pop into existence. Enough said. Eyes appear. Eyes emerge. Eyes develop. The Darwinist authors of the paper tell her they “now have an important tool to determine [trilobites’] position in the evolutionary tree” and she trusts them with childlike faith, not realizing that they have just confessed ignorance about the evolutionary tree. No wonder; there is none. Trilobites exploded into existence at the base of the animal fossil record: the Cambrian Explosion.

Exercise: The paper is open access. Look for all the hedging words that raise the perhapsimaybecouldness index (probably, possibly, may have, etc.). For example, they say “probably” 18 times, and “may have” 6 times. See if they establish a clear functional chain from simple to complex by small incremental steps without assuming evolution—a sequence involving random mutations “selected” by a blind, eyeless, aimless, uncaring environment.