What on Earth Was Ainiktozoon?

the fossil record is an incredible thing it gives us an invaluable glimpse into the ancient prehistory of our planet and the life that once inhabited it and without it we'd have very little clue about the long and complex evolutionary history of all the wonderful organisms around us today or indeed our own origins but sometimes the fossil record turns up something so incredibly weird and confusing that it just sends paleontologists absolutely mad this is indeed the case with an organism called eine kitazoon loganency a creature so bizarre that for many years since its initial description in

1937 paleontologists were looking at this animal upside down with it not being until 1997 that this mistake was finally realized remarkably not a great deal of research actually seems to have been done on this organism despite the appeal of solving such a strange fossil mystery and anikitizoon remains a pretty obscure prehistoric organism the first fossils of this creature were uncovered possibly as early as the mid-1890s with most of the original specimens used as the basis for its description being found during a geological expedition around 1904 32 fossils were originally recovered and the site of the

discovery was in the silurian aged ludlow group that outcrops in scotland after they were initially found the specimens changed hands a few times eventually though in 1937 the fossils were studied and described by crustacean experts dj scourfield who recognized that they likely all belonged to the same species and subsequently attempted to interpret their anatomy the main feature that was obvious in all the specimens he studied was a so-called capsule ovoid in shape that on one end connects to a broad zone of parallel bars he named the palisade on the upper surface of this palisade he

noted some fine branched siri and then also attached to the capsule were two segmented rods which he named the primary and secondary rods the primary segmented rod was the lower one in his interpretation and possessed a series of eight to nine sharply pointed bifurcated spines while the secondary rod is almost constant in width and meets with the primary at the end the two rods are then also connected along their length by structures that continue past the secondary rod and end in lobes nine or ten of these lobes were said to be present and in this

original interpretation they were not thought to be paired instead running in a single row down the middle of the rods other structures that were found preserved one of which projected from the capsule were named fascicles by scatter field the one connected to the capsule was illustrated as pointing downwards tapering towards the end and also curving slightly forwards at the end of this fascicle was then what he thought looked like a hook that was probably paired at the upper front margin of one of the fossil specimens was also a patch of sub-triangular regularly arranged little bumps

that he called the shagreen patch next to an even smaller c-shaped patch he named the auriculate organ various bands were also noted as crossing the fossil in various places and some indistinct regions of anatomy were also briefly recorded all in all scourfield was quite perplexed by what this incredibly unusual morphology meant in terms of this animal's relationships to other known groupings but he felt fairly confident that it was not a crustacean at least and instead classified it as some kind of early basal cordate the phylum to which we also belong he therefore gave it the

name anikitizune based on the greek four riddling or enigmatical animal it was then not until 1985 that another paper re-examining this organism was published by australian paleontologist alexander ritchie though it should be noted that a couple of other researchers had made their own brief interpretations of the animal before then but did not add much of significance richie ultimately agreed with scourfield's interpretation that aina kitazun was a sort of early caudate but based on newly available specimens that had been discovered in the years since the initial publication some more anatomical details were revealed these include a

mystery tube organ inside the body cavity the function of which was not understood as well as a fringe structure apparently attached to the tube this fringe comprises curved rods that display many small hair-like filaments along them and actually sit in the same place as the hook structure but both hook and fringe never occurred in the same specimen the french was proposed to have had some kind of reproductive function and thought to be placed internally while the hook was an external structure the hook then also seems to have supported a very delicate structure called the reticulate

area the function of which was again described as uncertain the most significant of the new anatomical discoveries in this paper though was the reinterpretation of the previously mentioned chagrin patch and auriculate organ in one of the newly discovered specimens these structures were preserved much more clearly and very obviously show that these are the remains of a compound eye made up of many tiny lenses the smaller auricular organ was the retinal body with a clear gap separating it from the outer lenses represented by the chagrin patch interestingly the eye was not interpreted as being paired with

it instead looking like anikitizune possessed a single large eye in the middle of the front-facing side of the body now you may be thinking that the identification of a compound eye would be some pretty damning evidence against this organism being a chordate and in favor of an arthropod affinity considering that arthropods are well known for possessing this type of eye morphology however richie defended the chordate interpretation by explaining how a lot of anekita zun's other anatomy does not conform with that of arthropods this creature apparently lacked any antennae jointed appendages or mouth parts was only

segmented in the tail and not in other locations across the body and had skeletal material that was interpreted as being more like certain unmineralized structures seen in tunicates a type of chordate than what is seen in arthropods other justifications were also given including arguing that the compound i was an example of convergent evolution leading richie to agree with scourfield that ainakitazun was a very bizarre chordate he considered it to be one that led an active free-swimming lifestyle and an inhabitant of deep quiet waters where it survived by filter feeding so while some more details of

this anatomy had been discovered this paper did not change a great deal about our understanding of this organism from what was already described in the original paper naming it but then just over a decade later in 1997 a different team of paleontologists quite literally turned everything upside down looking at the illustrations and interpretations made by scammerfield and then expanded upon by ritchie these paleontologists realized that if the site considered to be the upper surface was instead the lower one the fossils actually display a lot of anatomies that do in fact conform with arthropods examining a

few more newly found fossils too this research interprets anikitozune as possessing a tool carapace at the front which covered a segmented body from which eight branched limbs with paddles on the end project these being the logged structures that scatterfield originally identified as projecting from the rods the capsule with a filamentous siri on top now positioned upside down is considered to be a very muscular foregut and the siri thought to be gills and the so-called fascicles the odd bands inside the carapace and also connected to the capsule are said to be traces of phosphatized muscles which

would have dilated the stomach and moved the carapace one of the newly discovered specimens at the time of this researcher's publication also revealed something else that was very interesting near the front of the body under the carapace were what looked like a set of raptorial limbs all lying one on top of the other these limbs said to look like jackknifes by the authors had large segments that were equipped with tough spines and were presumably used in actively hunting prey items so this was not a slow-moving filter feeder all of this evidence therefore resulted in the

paleontologists reclassifying iron ketosune as an arthropod specifically in a class called thylakocephala this grouping contains a number of other very weird looking members that lived from potentially as early as the cambrian until the late cretaceous the exact classification of this clade within the arthropods is itself a bit of a mystery too but it's possible that they represent a lineage of crustaceans and that's about the last bit of major research that's been done on this organism the relatively little amount of work that's been done on this bizarre animal has honestly surprised me as i researched this

video i thought this significantly more would have been done on such a mysterious and extraordinary looking animal but i guess a combination of his obscurity and the difficulty involved in determining its true anatomy and affinities has led to eine ketzen slipping under people's radars or possibly even cause them to just be put off by studying such a difficult animal maybe this video will help to change things i certainly hope it's able to bring some more attention to this prehistoric enigma i have no doubt that eventually some more research will be done on this animal and

hopefully more specimens will be found too and i honestly wouldn't be surprised if other paleontologists end up interpreting it differently again whatever happens it will be very interesting to see anyway i really hope you enjoyed this video and learned something new a big thank you to our patreon supporters too especially our dinosaur tier supporters amanda von nordeck archaeanthus bella anderson dhruv srivastava elijah carrion george fragitec greg silvernail just f max corey peterson laura sanborn mike pace persian boy robert thomas staniforth hopkins and tiffany trammell if you would like to find out more about our world

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