Did you know that just this year, paleontologists have discovered new insights into the behavior
and appearance of Spinosaurus, the biomechanics of Megaladon shark teeth, and the strangest
early lifeforms of the Cambrian Explosion? New revelations are occurring all the time
regarding Earth’s distant past, yet these incredible findings often go unnoticed by
the general public. So, this year, I’m taking part in PaleoRewind, a breakdown of some of
the most important revelations in the field of Paleontology from the past year. All sorts
of other creators you might already be subscribed to are also participating. In this video,
I’ll kick the rewind off by covering findings from the first half of January — but be
sure to check out everyone else’s entries too, and the final 2021 compilation video
that will be uploaded on E.D.G.E.’s channel. Now let’s get started… Beginning in early
January 2021, we have new findings on the potential ecology and feeding behavior of
the famous theropod ‘Spinosarus.’ The Spinosarus is a dinosaur that has long gripped
popular culture in its elongated jaws thanks in part to its appearance in the Jurassic
Park franchise, but the common conception I grew up with of the Spinosarus as a bigger,
heavier T-Rex analogue isn’t quite accurate. Indeed, the Spinosaurus has been the subject
of considerable recent debate regarding its biology and ecology, as it might have been
highly unique from other carnivorous therapods due to its semi-aquatic or perhaps highly-aquatic
lifestyle. A paper published January 7th by Dr. David Hone and Dr. Thomas Holtz weighs
the likelihood of a Spinosaurus being a wading animal that fed on fish near the shorelines
and in shallow water, or a specialized aquatic pursuit predator. Their studies were quite
complex, but to simplify, based on the anatomy of the fossils we have and related ecological
data, the wading model is more supported than the highly-aquatic one. Still, the authors
note Spinosaurus almost certainly fed primarily from the water and may have swum, which alone
would make it incredibly distinct from most other large therapods… Our next discovery
exposes new revelations regarding the history of a highly adapted group of aquatic predators:
sharks. For hundreds of millions of years, sharks of various sizes have been patrolling
Earth’s oceans. And throughout the Cenozoic, an extinct family known as ‘megatooth sharks’
started to trend towards gigantism — a trend that culminated in the well known Megalodon:
the largest marcopredatory shark ever to exist. This species exceeded lengths of up to 15m
or 50 feet, and likely weighed more than 50 tons. But a mystery has long surrounded the
Megalodon regarding the nature of their teeth. Compared to the teeth of earlier megatooth
sharks, Megalodon teeth consistently had greater crown width, for reasons that aren’t entirely
clear. Recently, Dr. Antonio Ballell and Dr. Humberto Ferrón ran a series of experiments
testing the biomechanics of earlier megatooth shark teeth compared to the megalodon, and
the results were quite surprising. It seems stress distribution patterns were remarkably
similar across all models, meaning that the teeth of Megalodons — while obviously deadly
— weren’t any better adapted than the teeth of other sharks in their family. It
seems that megalodon teeth shifted in shape as a by-product of their gigantism, instead
of a specific evolutionary advantage. Still wouldn’t have been fun to get bitten by
one, though… Winding back the clock by half a billion years, we reach the Cambrian Explosion,
a metaphorical eruption in the diversity of early lifeforms, which, as of January 2021,
we have new information on. You might already know that the Cambrian Explosion gave rise
to countless bizarre lifeforms, many of which seem more like alien life than something from
Earth’s past. From the surreal Opabinia, which might have possessed a flexible trunk
that makes it look almost like a living cartoon, to the Hallucigenia, an animal so dreamlike
its name comes from the word ‘hallucination’ — it’s a fascinating early milestone in
earth’s biodiversity. And a recent examination by Dr. A.J. Shore and Dr. R. A. Wood unveils
a new addition to this pantheon of oddities. Through the analysis of some exceptionally
well-preserved fossils, researchers were able to distinguish a lifeform that possessed a
cup-shaped skeleton with six radially arranged lobes surrounding what was likely its mouth.
A reconstruction of this lifeform shows it was a highly unique form of animal, and perhaps
a foundational member of the lophotrochozoan clade — a group that today includes various
types of cephalopods and mollusks… In the realm of Paleontology, sometimes seemingly
small discoveries can lead to major revelations. One article from January 6th shows a curious
potential relationship between herbivorous dinosaurs and the plants that they ate. A
new examination of fossilized gut contents by Dr. George Perry suggests plant seeds remained
intact within the stomachs of plant-eating dinosaurs. Cross-referencing this data with
the distances they likely walked, it seems possible that herbivorous dinosaurs dispersed
plant seeds far and wide via their, well, droppings.Strange though this might sound,
some modern plant-munchers — like African bush elephants — play a similar role in
the, uh, seed dispersal of certain types of plants. In fact, the dispersal of plant seeds
within the bodies of animals is so frequent in current ecosystems that plants often modify
their fruits and flowers to appeal to specific species. And since some dinosaurs could consume
even more plant matter per day than elephants, it’s likely they were highly sought-after
seed distributers millions of years ago. A strange, but fascinating discovery… And
our last article covers a whole new taxon of marine predator, with specialized teeth
unlike those of any known reptile. This new taxon is a member of the Mosasauridae, a group
of mid-Cretacious lizards that became specialized for marine life. This exciting new taxon,
called Xenodens calminechari, lived just before the K-Pg extinction… and stands out from
all other mosasaurids. As reported in the article by Dr. Nathalie Bardet and Dr. Nicholas
Longrich, this new Mosasaurid possessed teeth that were hooked and formed a saw-like blade.
The specialized teeth suggests a previously unknown hunting strategy, likely involving
a cutting motion to carve pieces out of large prey. Or perhaps these unique teeth were used
for scavenging already deceased marine lifeforms. In either case, these teeth are unique not
just among mosasaurids, but reptiles in general. An incredible finding. And those are just
some of the major paleontological revelations of early January. Special thanks to E.D.G.E.
for inviting me to be a part of PaleoRewind. Other channels like mine will be releasing
videos covering other months in the coming days, and I’ll add links to them in the
description when they upload. And Paleo Analysis is covering the second half of January, so
check out their video next if you want to go in order. And as always, thanks for watching.
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