Calling on the Colibris, DFs, and Blakes of the board… 
What do we know about the evolution of bats? How good is the fossil record?
IIRC, the genetic data suggest they are related more closely to primates than to other mammal groups, but I’m not even certain about that.
There’s all kinds of good info out there on the evolution of cetaceans, but I’ve been unable to find anything on bats. Thanks in advance for the help!
Well here’s this according to UCBerkeley, the fossil record of Chiroptera.
The answer is, 1) not much, and 2) the fossil record is terrible.
As DeVena’s link indicates, bats fossilize poorly so there’s not a lot to go on. When bats appear in the fossil record, in the Early Eocene of North America and Europe, they have almost all the characteristics of modern bats, including fully developed wings.
Because of this, there is a great deal of controversy over what other groups may be their closest relatives. As in some other groups, the data from morphology is at odds with the genetic data - possibly because mammalian diversification was so rapid in the Paleocene that it makes the genetic branching pattern difficult to sort out. There is even controversy whether the two major groups of bats, the megabats (Megachiropterans, the large fruit bats) and the microbats (Microchiroptera, all the other bats) are even each other’s closest relatives, or whether they are derived from different groups and merely convergent. (IMO, the latter is unlikely due to the very close similarity in wing structure.)
From here:
Thanks. I was afraid that was the situation (my Googling skills aren’t that bad).
You’d think, though, with the large number of bat species and the large number of individual animals, that the fossil record would be a bit better. I mean, they can fly, afterall, so their fossils shouldn’t be so geographically restricted.
The problem may not have been so much geographical as habitat. The early stages of bat evolution may have taken place in a tropical forest environment, which is particularly bad for fossilization - not only is decay extremely rapid, but the soil is acidic and virtually dissolves bones. Small animals from such habits stand almost no chance of fossilization. Mountain areas are also bad, since there is little if any deposition of sediments. If ancestral bats lived in tropical mountain areas, there is little chance we will ever find them.
Ancestral whales, on the other hand, were large animals living in coastal and near-shore habits, an ideal environment for fossilization.
I tend to agree with the previous posters, but here is what I know.
Simplified bat evolution timeline:
Wood->Plastic->Aluminum
Though there is little doubt in the scientific community that all bats share Wood as a common ancestor, there is much debate about whether the Plastic Bat and Aluminum Bat are sub-species of Wood (like Ash and Hickory) or completely separate species. There is no credible evidence of Wood/Aluminum, Plastic/Wood, Aluminum/Plastic hybrids which leads scientists to believe that they cannot interbreed, but the mating habits of these creatures is poorly documented. Please note that the fairly common Wood/Cork hybrids are completely due to human intervention. No pure Cork Bat exists in the wild. A pure Cork Bat would never withstand the rigors to which it’s body would subjected and would quickly become extinct. Most Wood Bats seem originate near Louisville, KY (though Japan has one or two large breeding areas) but how the parents journey back to that site is a mystery. Aluminum and Plastic Bats are less picky about where (geographically) they produce their litters. All bats produce litters year round.
There are, as far as I know, no “fossilized” remains for scientists to study. This is due in large part to the fact that Wood Bats tend to deteriorate rapidly and not fossilize at all while their Aluminum and Plastic bretheren have not been around long enough to establish a fossil record. Fortunately, both Aluminum and Plastic Bats decompose very slowly leaving many “bodies” lying around for scientific study. Several thousand private collectors and some museums (particularly the one in Cooperstown, NY, which specializes in Wood Bats) have wonderful collections of preserved bats that one can view.
Wood Bat numbers seem to be on the decline from their hayday in the 1950’s and 1960’s. There are a few select areas where the numbers appear to be sustainable for the foreseeable future, particularly in 30 US cities. Both Aluminum and Plastic Bats seem to be producing in sufficient numbers to sustain populations over a large part of the earth.
Oh! How I wish this useful, domesticated creature were better understood!
a post just to let Doctor Jackson know that someone appreciates his wit
