Most trilobites had compound eyes comparable to those that are still discovered in pests today: a large number of hexagonal elements form the eye. Comparable to the image of a computer system screen, which is developed up from individual pixels, an image is constructed up from the individual elements.
However, in the trilobite suborder Phacopinae, the externally visible lenses of the compound eyes are much bigger, approximately 1 mm in size and more. In addition, they are set farther apart. Previously, researchers had actually not been able to discuss this due to the fact that space is squandered where light could be recorded. Because a little cup sits under the lens, they assumed that at the bottom of the capsule was a small retina similar to that of humans.
Dr. Schoenemanns analysis of Wilhelm Stürmers 40-year-old X-ray archive now recommends a different analysis: a hyper-compound eye. “Each of these eyes consisted of about 200 lenses up to 1 mm in size,” stated Schoenemann. The filaments Stürmer found in reality did turn out to be nerves leading from the eyes to the trilobites brain.
Wilhelm Stürmer was the head of the X-ray department at Siemens and an avid paleontologist. With a VW bus geared up as an X-ray station, he drove from quarry to quarry to X-ray fossils. Among other things, he found structures called filaments under the animals eyes, which he believed were fossils of soft tissues, specifically optic nerves. “At that time, the agreement was that only teeth and bones, the tough parts of living things, could be seen in the fossils, but not the pulps, such as intestines or nerves,” Schoenemann explained. Stürmers beneficiary offered the zoologist his archive. But the hobby-paleontologist had not only correctly identified the optic nerve, she notes: “On an X-ray negative, there was an arrow in red pen pointing to the structure of the 6 lower elements under a main lens. This probably suggested that Stürmer had already recognized the hyper-compound eye.” At the time, nevertheless, scientists presumed that nerves did not fossilize, nor that light guides existed in natural optical system. Optical fibers were not discovered until the 1980s in the compound eyes of a deep-sea crab.
Far, such an eye has actually just been discovered in the trilobite suborder Phacopinae: “This is special in the animal kingdom,” she concluded. In the course of development, this eye system was not continued, because the trilobites of the suborder Phacopinae passed away out at the end of the Devonian duration 360 million years back.
Referene: “A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites” by B. Schoenemann, E. N. K. Clarkson, C. Bartels, W. Südkamp, G. E. Rössner and U. Ryck, 30 September 2021, Scientific Reports.DOI: 10.1038/ s41598-021-98740-z.
Phacops geesops, a trilobite from the Devonian age. The animals eyes include 200 single lenses each, spanning six little aspects, which again form one eye each. Credit: Dr. Brigitte Schoenemann
Trilobites of the suborder Phacopina had an unique eye in which about 200 big lenses in each eye spanned a minimum of 6 private elements, each of which in turn formed its own little substance eye/ 40-year-old X-ray photographs by amateur paleontologist Wilhelm Stürmer show fossilized eye nerves.
An international research team has found an eye system in trilobites of the suborder Phacopina from the Devonian (390 million years B.P.) that is special in the animal kingdom: each of the about 200 lenses of a hyper-facet eye covers a group of six typical compound-eye-facets, forming a substance eye itself. In addition to the hyper-facetted eyes, the scientists, led by zoologist Dr. Brigitte Schoenemann at the University of Colognes Institute for Didactics of Biology, recognized a structure that they think to be a local neural network which directly processed the info from this special eye, and an optic nerve that carried information from the eye to the brain. The post, A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites, has been published in Scientific Reports.
Trilobites are arthropods that as soon as populated the worlds oceans and became extinct about 251 million years ago. The discovery was made when Schoenemann and her coworkers examined X-ray images taken by radiologist and amateur paleontologist Wilhelm Stürmer in the 1970s. Stürmer had actually already thought the filaments under the trilobite eyes to be nerves, or a light guiding system. Schoenemann also discovered markings by Stürmer on the images designating the 6 subfacets. Researchers at the time did not think his interpretations. Now, nevertheless, the re-examination of the images and verification with modern-day computed tomography succeeded in confirming his conjectures.
The animals eyes consist of 200 single lenses each, covering 6 little elements, which again form one eye each. A worldwide research group has actually found an eye system in trilobites of the suborder Phacopina from the Devonian (390 million years B.P.) that is special in the animal kingdom: each of the about 200 lenses of a hyper-facet eye covers a group of 6 regular compound-eye-facets, forming a substance eye itself. In addition to the hyper-facetted eyes, the researchers, led by zoologist Dr. Brigitte Schoenemann at the University of Colognes Institute for Didactics of Biology, determined a structure that they believe to be a regional neural network which directly processed the information from this special eye, and an optic nerve that carried info from the eye to the brain. A lot of trilobites had compound eyes similar to those that are still found in bugs today: a large number of hexagonal elements form the eye. In the trilobite suborder Phacopinae, the externally visible lenses of the compound eyes are much bigger, up to 1 mm in size and more.
