500 million year-old fossils reveal answer to evolutionary riddle | EurekAlert!
It must be galling to the leaders of the Creationist cults when science closes yet another gap and casually refutes the misleading claims they have fooled their cult followers with. It's much easier for the frauds to play to the parochial ignorance and childish thinking of their followers who will always assume that if science can't explain something, the locally popular god must have done it, ignoring the false dichotomy fallacy underpinning that deception.
Some of the gaps are artificial, obviously, being created by Creationists from misrepresentations of the actual science, such as claiming there are no transitional fossils showing, for example, a half chimpanzee - half human, but some of them are genuine gaps in the fossil record, although these tend to be ignored by creationist frauds because it would require a detailed knowledge of the evidence to appreciate where the real gaps are, and a detailed knowledge of the evidence is something no Creationist can afford to have.
One such gap, until now, was the early evolution of skeletal animals. The first fossils of skeletal animals appeared in the fossil record 550-520 million years ago during the so-called the Cambrian Explosion, which must be one of the slowest explosions on record, occurring over several tens of millions of years, but nevertheless a period of rapid evolution and diversification into different body-plans in the early history of multicellular organisms.
Many of these early fossils are simple hollow tubes ranging from a few millimetres to many centimetres in length. However, what sort of animals made these skeletons was almost completely unknown, because they lack preservation of the soft parts needed to identify them as belonging to major groups of animals that are still alive today.
Now though, a team of palaeontologist led by Dr Luke A. Parry of the Department of Earth Sciences, University of Oxford, Oxford, UK, Dr Xiaoya Ma and PhD student Guangxu Zhang, of the Institute of Palaeontology, Yunnan University, Kunming, People's Republic of China, and Dr Jakob Vinther from the Schools of Earth Sciences and Biological Sciences, University of Bristol, UK have analysed a collection of exceptionally well preserved fossils from 514 million years ago that include four specimens of Gangtoucunia aspera with soft tissues still intact.
Just to clarify that , soft-tissue term, before Creationist quote miners misrepresent it: fossilised soft tissue is not soft. It simply means the soft tissue was preserved long enough for it to become mineralised, just as bones, shells and teeth become mineralised in fossils of hard tissue. It is not evidence that these fossils are just a few thousand years old, like Creationist fraud claim dinosaur soft tissue fossils are (they are not soft either, by the way).
Before long, we can expect Creationists to either be claiming these 'soft tissues' have been carbon-dated and found to be recent, or that they haven't been carbon-dated because the scientists were afraid they would be found to be recent!
As the Oxford University News release explains:
Fossil specimen (left) and diagram (right) of Gangtoucunia aspera preserving soft tissues, including the gut and tentacle.
Image credit: Luke Parry and Guangxu Zhang.The new collection of 514 million year old fossils includes four specimens of Gangtoucunia aspera with soft tissues still intact, including the gut and mouthparts. These reveal that this species had a mouth fringed with a ring of smooth, unbranched tentacles about 5 mm long. It’s likely that these were used to sting and capture prey, such as small arthropods. The fossils also show that Gangtoucunia had a blind-ended gut (open only at one end), partitioned into internal cavities, that filled the length of the tube.Fossil specimen of Gangtoucunia aspera preserving soft tissues, including the gut and tentacles (left and middle). The drawing at the right illustrates the visible anatomical features in the fossil specimens.Image credit: Luke Parry and Guangxu Zhang.
These are features found today only in modern jellyfish, anemones and their close relatives (known as cnidarians), organisms whose soft parts are extremely rare in the fossil record. The study shows that these simple animals was among the first to build the hard skeletons that make up much of the known fossil record.
According to the researchers, Gangtoucunia would have looked similar to modern scyphozoan jellyfish polyps, with a hard tubular structure anchored to the underlying substrate. The tentacle mouth would have extended outside the tube, but could have been retracted inside the tube to avoid predators. Unlike living jellyfish polyps however, the tube of Gangtoucunia was made of calcium phosphate, a hard mineral that makes up our own teeth and bones. Use of this material to build skeletons has become more rare among animals over time.
The new specimens clearly demonstrate that Gangtoucunia was not related to annelid worms (earthworms, polychaetes and their relatives) as had been previously suggested for similar fossils. It is now clear that Gangtoucunia’s body had a smooth exterior and a gut partitioned longitudinally, whereas annelids have segmented bodies with transverse partitioning of the body.This really is a one-in-million discovery. These mysterious tubes are often found in groups of hundreds of individuals, but until now they have been regarded as ‘problematic’ fossils, because we had no way of classifying them. Thanks to these extraordinary new specimens, a key piece of the evolutionary puzzle has been put firmly in place.
Dr Luke Parry, Corresponding author
Department of Earth Sciences
University of Oxford, Oxford, UK
The fossil was found at a site in the Gaoloufang section in Kunming, eastern Yunnan Province, China. Here, anaerobic (oxygen-poor) conditions limit the presence of bacteria that normally degrade soft tissues in fossils.
The first time I discovered the pink soft tissue on top of a Gangtoucunia tube, I was surprised and confused about what they were. In the following month, I found three more specimens with soft tissue preservation, which was very exciting and made me rethink the affinity of Gangtoucunia. The soft tissue of Gangtoucunia, particularly the tentacles, reveals that it is certainly not a priapulid-like worm as previous studies suggested, but more like a coral, and then I realised that it is a cnidarian.
Guangxu Zhang, first author
Yunnan Key Laboratory for Palaeobiology and MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment
Institute of Palaeontology
Yunnan University, Kunming, People's Republic of China.Although the fossil clearly shows that Gangtoucunia was a primitive jellyfish, this doesn’t rule out the possibility that other early tube-fossil species looked very different. From Cambrian rocks in Yunnan province, the research team have previously found well-preserved tube fossils that could be identified as priapulids (marine worms), lobopodians (worms with paired legs, closely related to arthropods today) and annelids.A tubicolous mode of life seems to have become increasingly common in the Cambrian, which might be an adaptive response to increasing predation pressure in the early Cambrian. This study demonstrates that exceptional soft-tissue preservation is crucial for us to understand these ancient animals.
Dr Xiaoya Ma, corresponding author
Yunnan Key Laboratory for Palaeobiology and MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment
Institute of Palaeontology
Yunnan University, Kunming, People's Republic of China
And Centre for Ecology and Conservation
University of Exeter, Penryn, UK
Close up photograph of the mouth region of Gangtoucunia aspera showing the tentacles that would have been used to capture prey.
Image credit: Luke Parry and Guangxu Zhang.
AbstractSo, we now know that the earliest skeletal animals were cnidarians, from the same group as corals, jellyfish and anemones, but with an exoskeleton composed of calcium phosphate - the predominant mineral in the bones of vertebrates, and another gap slams shut, albeit one of which most creationists would be totally unaware.
Exoskeletal dwelling tubes are widespread among extant animals and early fossil assemblages. Exceptional fossils from the Cambrian reveal independent origins of tube dwelling by several clades including cnidarians, lophophorates, annelids, scalidophorans, panarthropods and ambulacrarians. However, most fossil tubes lack preservation of soft parts, making it difficult to understand their affinities and evolutionary significance. Gangtoucunia aspera (Wulongqing Formation, Cambrian Stage 4) was an annulated, gradually expanding phosphatic tube, with occasional attachments of multiple, smaller juveniles and has previously been interpreted as the dwelling tube of a ‘worm’ (e.g. a scalidophoran), lophophorate or problematicum. Here, we report the first soft tissues from Gangtoucunia that reveal a smooth body with circumoral tentacles and a blind, spacious gut that is partitioned by septa. This is consistent with cnidarian polyps and phylogenetic analysis resolves Gangtoucunia as a total group medusozoan. The tube of Gangtoucunia is phenotypically similar to problematic annulated tubular fossils (e.g. Sphenothallus, Byronia, hyolithelminths), which have been compared to both cnidarians and annelids, and are among the oldest assemblages of skeletal fossils. The cnidarian characters of G. aspera suggest that these early tubular taxa are best interpreted as cnidarians rather than sessile bilaterians in the absence of contrary soft tissue evidence.
Figure 3. Specimens preserving internal details of the digestive system. (a–d) YKLP 11437; (e–h) YKLP 11438. (a) Overview of specimen showing soft tissues partially extruded from the dwelling tube. (b) Detail of boxed region in (a) showing longitudinal gastric septa using low angle lighting. (c) Interpretative drawing of (b) highlighting the morphology of the digestive tract and gastric septa. (d) High angle light image of digestive tract showing extent of the gastric septa demarcated by dark linear structures. (e) Overview of specimen with high angle illumination. (f) Overview of specimen as in (e) with low angle illumination. (g) Interpretative drawing of region shown in (e,f) highlighting the trajectory and morphology of the digestive tract. (h) Close up of three dimensionally preserved septa.
Zhang, Guangxu; Parry, Luke A.; Vinther, Jakob; Ma, Xiaoya (2022)
Exceptional soft tissue preservation reveals a cnidarian affinity for a Cambrian phosphatic tubicolous enigma
Proceedings of the Royal Society B: Biological Sciences; 289(1986), 20221623. DOI: 10.1098/rspb.2022.1623
Copyright: © 2022 The authors.
Published by The Royal Society. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
On this occasion, the 'gap' proved to be the result of the right fossils not being found yet. The fact that they exist and neatly fill that gap is good evidence in itself that the Theory of Evolution is true, since the existence of these 'transitional' species is a prediction of the theory and finding them is a vindication of it.
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