A newly discovered dinosaur came with a delightful surprise, but it's not the only wonder of its kind.
Daurlong wangi escaping a fire. Credit: Ivan Iofrida, Wikimedia Commons, CC-BY-SA 4.0.
When's the last time you saw fossilized guts in a museum? In the days when Jurassic Park first came out you would have been laughed at for even suggesting organs and blood and soft bits could survive millions of years to become fossils. But this is 2022, and science has come a long way, and now you're the one who'd be laughing at such closed-minded thinking. Why? Well, I'm about to show you.
This article was prompted by a newly-discovered dinosaur species called Daurlong wangi, the founding fossil of which contained preserved intestines. Well, technically it is a mineral mold of a part of the organ, but still, it's a fascinating find.
Daurlong wangi is a 1.5 m (5 foot)-long discovered in China that lived during the Cretaceous period. It is a new dinosaur, so not too much is known about it yet. But the preservation of intestines in this exquisite specimen is telling scientists a lot about dromeasaur eating habits. In the image below, the dark, bluish-gray splotch toward the right is the intestinal remains (just above the femur in the full-body picture in Figure 1 below).
Figure 1: The Daurlong specimen discovered by scientists in China. d) Feathers on thoracic vertebrae (backbone). b) Close-up of the skull. c) Close-up of orbit area (eye socket). Credit: Wang, X, et. al., Scientific Reports (2022), CC-BY 4.0.
Figure 2: Chest/abdomen region of specimen. The blackish spot on the right is the intestines. The label "mcII" is the second metacarpal. I-1 & I-2 are the phalanges of the first digit (finger). "III" labels mark the third digit. "st" is the sternum (breastbone). The left arm was folded back over the body of the animal, hence the presence of the fingers here. Credit: Wang, X, et. al., Scientific Reports (2022), CC-BY 4.0.
Figure 3: Life reconstruction of Daurlong wangi. Credit: Ivan Iofrida, Wikimedia Commons, CC-BY-SA 4.0.
You would think this sort of find would be the first of its kind, but in fact several such discoveries have happened so far this century. One of the major "impossible" finds to make the news was fossils with color. Remember back in the old days when they said we'd never know what colors dinosaurs were because color can't be fossilized? Well, turns out it can be. Some of my favorite examples are Sinosauropteryx, Anchiornis, Microraptor, and Archaeopteryx. Scientists found melanosomes in the feathers of these animals and were able to use fancy microscopic scanning technology to analyze the structures of these color-producing molecules. With this, they were able to elucidate the most likely colors the animals displayed.
Figure 4: Top to bottom: Sinosauropteryx (Smithwick, F M, et. al., Wikimedia Commons, CC-BY-SA 4.0.), Anchiornis (Matt Martyniuk, Wikimedia Commons, CC-BY 3.0.), Microraptor (Fred Wierum, Wikimedia Commons, CC-BY-SA 4.0.), Archaeopteryx (DBCLS, Wikimedia Commons, CC-BY 4.0.).
Sinosauropteryx is also unique in being the first dinosaur to have its true colors described. Archaeopteryx, however, was the first dinosaur to be discovered with feathers and establish a link between birds and dinosaurs. This little creature, along with others like Sinosauropteryx, helped launch a revolution in paleontology (the study of prehistoric animals) and are why everyone now thinks dinosaurs were feathered.
Figure 5: Original Archaeopteryx fossil. Credit: H. Raab, Wikimedia Commons, CC-BY-SA 3.0.
As far as actual organs, like intestines, goes, Daurlong isn't alone in that, either. A nearly complete Scipionyx specimen, another theropod dinosaur from Italy, was also found with intestinal remains. In fact, not only was that specimen the original holotype for its genus, but it also contains so many other soft tissues that it is nothing short of amazing. Some of these tissues include bits of the trachea, blood stains from the heart/spleen/liver, muscle, cellular structures, and cartilage.
Figure 6: Scipionyx samniticus fossil. Top: complete specimen. Bottom left: up-close of chest/abdominal area; curly, bulbous brown structure is small intestine, and red stain is blood likely from heart/liver/spleen. Bottom right: up-close of head & upper neck. Credit: Giovanni Dall'Orto, Wikimedia Commons, CC.
The Scipionyx specimen is very small, about 50 cm (a little over a foot) in length. Because of this, it is assumed to be a very young dinosaur. The specimen contains no obvious traces of feathers, but it's not unlikely the dinosaur had some such covering in life, at least as an adult. The lack of feathers in this fossil could be because, like modern birds, the species had few to no feathers at the specimen's young age, or the feathers simply could have failed to be preserved.
Figure 7: Preserved soft tissues in Scipionyx fossil highlighted and color-coded. Credit: PaleoEquii, Wikimedia Commons, CC-BY-SA 4.0.
Figure 8: Scipionyx samniticus as it might have looked and behaved in life. Credit: PaleoEquii, Wikimedia Commons, CC-BY-SA 4.0.
The Scipionyx fossil is amazing enough, but it gets even better. Enter Borealopelta - the mummy dinosaur. OK, it's not technically a "mummy", but it's close enough. This Canadian nodosaur fossil came with near-complete body armoring, as well as some pigment indicating reddish-brown coloration.
Figure 9: Borealopelta fossil. Credit: Etemenanki3, Wikimedia Commons, CC-BY-SA 4.0.
Finally, a T-rex was discovered with original blood-vessel tissue and preserved cells. I'm not joking. The tissue was actually still elastic, which should be impossible for a creature that died 66 million years ago. The scientists who discovered this fossil cleaned it multiple times over to ensure the soft tissue wasn't some microbial contamination introduced much later. But nope - it was actual, real blood vessels and cells. Wow. Just wow. Perhaps this find is evidence that the T-rex species survived the Cretaceous extinction? OK, now I'm joking. But the scientists did learn how such delicate structures could have been preserved for so long, and it has to do with protein cross-linking.
Figure 10: Soft tissue extracted from the T-rex femur. The tissue is elastic and returns to its former shape when stretched (arrow in A). Credit: Schweitzer et al., Science 307:1952-1955 (2005).
Figure 11: A, C, E, & F are samples from the T-rex bone and show structures highly reminiscent of ostrich osteocytes (bone cells) (B & D). Credit: Credit: Schweitzer et al., Science 307:1952-1955 (2005).
Figure 12: A, C, D, & E are from the T-rex bone. A & C show structures which look awfully similar to to ostrich blood vessels (B). D is an exploded vessel from the T-rex, revealing little round objects that are likely red blood cells. E shows possible epithelial cells from the T-rex, compared with similar structures in the ostrich in F; however, these may be left over from the dehydration process used to prepare the specimens for study. Credit: Schweitzer et al., Science 307:1952-1955 (2005).
It seems that every time we think we've got it, something new is found that makes scientists squeal with delight and laymen marvel at how nature can be so wonderful. There are many more specimens paleontologists have discovered that boggle the mind, but these are some of my favorites. Who knows what scientists will discover next?