Cat gap

Additionally, they got hungry.

https://en.wikipedia.org/wiki/List_of_nearest_galaxies

I presume this is due to a lack of mummified cats in my walls, which would clearly keep mice mummies away, so I shall precure some posthaste!

I only knew that cats go into hiding then they feel their end is near, that they do this on their own. Thus most "cat is missing" posters actually mean their cat died but kept it secret from its humans.

"Bat fossils are extremely rare. Ancient bats, like their modern counterparts, were small and fragile, and they tended to live in tropical habitats, where decay occurs very rapidly. Just about the only way a bat can become fossilized is if it dies in a place where it is swiftly covered with sediment that protects it from scavengers and microorganisms alike."

However a transitional bat fossil was discovered around 2000, so probably after your school book was written:

"Onychonycteris, however, has a combination of archaic and modern traits that make it exactly the sort of transitional creature evolutionary biologists have longed for.

"We chose the genus name Onychonycteris (“clawed bat”) because the fossil displays claws on all five fingers, just as its terrestrial predecessors did. The presence of these claws is not the only feature of Onychonycteris that recalls nonflying mammals. Most bats have very long forearms and tiny hind limbs. Onychonycteris, however, has proportionately shorter forearms and proportionately longer hind limbs than those of other bats. Compared with other mammals, the limb proportions of Onychonycteris are intermediate between those of all previously known bats (including Icaronycteris) and those of arboreal mammals that rely heavily on their forelimbs for locomotion, such as sloths and gibbons. These animals hang from branches much of the time as they climb around in the trees. Perhaps bats evolved from arboreal ancestors that used a similar form of locomotion.

"Despite these primitive limb features, other aspects of the anatomy of Onychonycteris indicate that it was capable of powered flight. Its long fingers would have supported wing membranes, and robust clavicles (collarbones) would have helped anchor the forelimbs to the body. Meanwhile a wide rib cage and a keeled sternum would have supported large flight muscles, and a faceted scapula would have secured other specialized, flight-related muscles."

https://www.scientificamerican.com/article/uncovering-bat-ev...

https://www.youtube.com/watch?v=SIgv8Qw--kk

Like the flying squirrel example given by another poster, they're not closely related to bats. Actually quite closely related to us though.

Bats: https://www.onezoom.org/life/@CHIROPTERA=574724 Colugos: https://www.onezoom.org/life/@DERMOPTERA=987673 Flying squirrels: https://www.onezoom.org/life/@Petinomys=43434 Sugar gliders: https://www.onezoom.org/life/@Petauridae=323245

But the bat transitional fossils is also an interesting question. And some Googling finds this, which you might enjoy: https://arstechnica.com/science/2008/02/earliest-bat-fossil-...

Fossils are actually incredibly rare, especially at more than a couple of million years old. For every fossil, there were probably a million dead critters that never became fossils (figure pulled right out of my nethers).

Nowadays, it's a given that birds are dinosaurs (theropods, to be precise). There have been enough transitionals, to establish that. I think the latest Jurassic Park finally has a feathered dinosaur in it. When the first movie came out, the look of the "lizards" was pretty much what everyone thought, so a lot has happened, in less than thirty years.

Honestly it's amazing we know as much as we do. It's not easy to preserve something for hundreds of years, let alone millions or billions.

The fortunate bit for them is that science is a slow, human discovery process and will always have gaps. For a scientist, this is where the wonder of science is: making hypotheses about things we don't know and then going out and finding it with as much rigor as they can think to apply.

The unfortunate bit for these particular sorts of believers that can't imagine their God living in science, that can't imagine their God wanting people to know as much about the world around them as possible, is that while there are always gaps, they are always shrinking or getting "solved" with new theories or new records/discoveries. At some point the only way to "protect the gaps" and thus protect their idea of God, their God of the Gaps, is to lean hard into ignorance and distrust of science. (Sometimes I almost feel sorry for them and that lack of imagination and/or trust that their God cannot exist in science/beyond just hiding in gaps like a creature of darkness.)

As another example of a "closed gap", in addition to some of the other good ones in sibling comments here, that I appreciate because it is very much an ur-example in that a symbol for atheism in counter to that gap has long been the "evolve fish" with legs, which also long seemed like a gap in the fossil record, especially to the "God of the Gaps" crowd.

Since those days we've closed that gap and found fossils of the Tiktaalik and done all sorts of science around the first land fishes, our lobe-finned ancestors that made the first "steps" onto land, the real life "evolve fish": https://en.wikipedia.org/wiki/Tiktaalik

The plush form is very cute if you want a memento of this scientific discovery. Currently sold out, but some museums may have some: https://pri-gift-shop.myshopify.com/collections/plush/produc...