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Saturday, April 24, 2021

No Future for the Pterosaurs

The ecological niches filled by familiar species in our era were in distant prehistory occupied by other species. Life has been humming along for billions of years in this world, seemingly endless days that in abundant numbers make up not only centuries and millennia but periods, eras, and epochs. It is incredibly difficult for the human mind to conceive of deep time. And in those many millions upon millions of years life has taken forms to fill niches that show a certain continuity, in that they are adapting to the same or similar circumstances.

A pair of recently-published papers have introduced a couple of new pterosaurs to the scientific world and provide us insight into the niches these creatures were able to inhabit. So we're clear, pterosaurs are technically a type of lizard, and included the pterodactyl among at least 130 pterosaur genera. They in the late Triassic Period and endured until the late Cretaceous Period (228 to 66 million years ago), going extinct along with the dinosaurs. Further, modern birds are not descended from these reptiles, but rather from avian dinosaurs. 

One of the newly-described species is the Kunpengopterus antipollicatus, nicknamed 'Monkeydactyl.' It has received that moniker for having opposable thumbs and living in trees. The other, anurognathid, has a passing resemblance to the porgs of Star Wars: The Last Jedi. Both of these species of pterosaur lived around 160 million years ago, and were uncovered in China.
Monkeydactyl, as it's been called, appears to be the earliest animal to sport an opposable thumb, such that it could touch its thumbs to its other fingers. Its physiology leads paleontologists to believe that it was adapted to life in trees, consuming insects and similar prey. While closely-related varieties of pterosaur existed in the same time and place, so far no others have been found to have similar adaptations to an arboreal existence. In our times tree frogs and certain types of primates fill this ecological niche.
Anurognathids, for their part, had small bodies, membranous wings, and a thin tail. Their proportionally huge eyes were likely advantageous in low-light conditions as they snatched insects into their wide, grinning mouths. These diminutive pterosaurs were probably fuzzy, having a pelt of tufted pycnofibers that were neither hair nor feathers. Where the Kunpengopterus antipollicatus was in the same space as arboreal primates and tree frogs in our times, anurognathids were more like the bats of the late Jurassic. To me they look more like little sky gremlins than cuddly porgs.
Consider now how long it took for these and other ecological niches to be filled again. After the meteor struck the earth, ending the Cretaceous and initiating the Paleogene, three quarters of life on earth went extinct in a matter of between 10,000 and 20,000 years. That might seem like a lot to us small humans with our brief life spans measured in decades, but in geologic time it's a blink of an eye.  All non-avian dinosaur species, millions of varieties of microscopic organisms, and a vast array of invertebrates were wiped out. Plant species suffered as well, with loss from diminished sunlight in the short-run, to a dramatically changed planetary climate in the long-run. It took between 4 and 10 million years for a full restoration of biodiversity to occur. That means that for millions of years there were roles not being played in the environment. Perhaps it was quite a while before bats and monkeys took the places of creatures like the flying porgs and monkeydactyls. 

As I indicated in the opening paragraph, we're dealing here with spans of time that are inconceivable to the human mind. We can talk about them, but rarely do we glimpse the actually scale of time we're considering here. 
The tyrannosaurus rex is closer in time to us that the stegosaurus is to the t-rex. Think about that for a few seconds. When I was a child I had little toy dinosaurs, all from different time periods and mixed together. Although it was known to scientists that these creatures lived in vastly different times, this information didn't filter out to the public easily. Perhaps with the internet we now have better access to learn such things that we miss in school, but we still have a tendency to lump all known varieties of dinosaur together. Based on lengths of time involved, it would actually make more sense (but still be ridiculous) to associate t-rex with the time of humans than with that of the stegosaurus.

In this unfathomably ancient world of ours many species have come and gone. Our own species has only been around for 200,000 of the 3.5 to 4 billion years that life has existed in this planet. The hubris of apocalyptic religious beliefs that center human history in the vast scheme of things are laughable by comparison. If the lineage of our species doesn't eventually go extinct, I'm convinced that as our kind spreads out first throughout the solar system and then to other star systems, evolution and adaptation will take place. Some may be guided by our hands, with genetic engineering to enable better suitability to life in space and on alien worlds, and other aspects will probably be just what happens over time. We are, after all, talking about a future of many millions of years stretching into billions.

If any of this is to matter, each generation as an obligation to those that follow to make the conditions for life better, not worse. Pterosaurs and dinosaurs could do nothing to avoid extinction. Humanity is in a different position, and it will take the cumulative miniscule but ultimately necessary actions of each age to ensure a future full of life for beings that proceed from our genetic heritage. If not, surely in due time some species might arise to take the place we vacated through ignorance.