I thought these two websites might be of interest here. The first is one that lets you enter the names of two taxa and it will tell you approximately when their most recent common ancestor lived. It also cites its sources from peer reviewed literature:
I tried a few things as tests, and see that they aren’t totally up-to date on some mollusks (values a bit higher with new fossils found). Generally fairly close (e.g. Ebala and Murchisonella should be more like 360 MYA, instead of 320).
The timetree site is a compilation of molecular clock dates. As such, the confidence interval has some chance of including a credible time, but that’s about as positive as I would get. Certainly the dates given for common ancestry of Cardiidae and Tellinidae are unreasonable, even though the compilation missed some published molecular clock dates for Cardiidae that are based on spurious calibrations.
The groupings in the OneZoom Tree within Bivalvia and Gastropoda are pretty random.
Both seem to suffer from the common problem of “look at all the great things that we can do with the data” without “look at the data quality and whether anyone is supporting research to generate and verify the data”.
Might it be that the quality of the data is uneven due to some parts of the tree being studied more extensively than others? I don’t think either of these are the kind of thing that someone puts together as a side project to post on Hacker News – they both appear to be produced by teams of evolutionary biologists with the help of data scientists and web developers. TimeTree for example is produced by the Institute for Genomics and Evolutionary Medicine at Temple University in Philadelphia, Pennsylvania. They are open to receiving corrections based on published studies.
Even if the quality of the data is spotty in places, what impresses me most about these sites is just how much data they contain. For something that certain people expect us to believe to be “only a theory,” the amount of detail in evolutionary biology is staggering. I can’t for the life of me see how the whole scientific community could be making up something that extensive and that detailed out of whole cloth.
Partly. Some of it is also due to studies that used a bad correlation (a published speed for 1-year lifespan organisms applied to ones that live a few decades, picking what seems like a relevant geological event that actually isn’t, etc.).
Some of it is the level of study. For example, only a few studies are cited in the TimeTree for bivalves. But studies on bivalves that are cited for some pairs are not cited for other pairs covered in that study - there seems to be some lack of knowledge about the groups, leading to inaccurate integration of data into their database.
But if you pick a more frequently studied pair, say Homo and Pan or Homo and Mus or Homo and Didelphis, and look at the range of dates given for the divergence by individual studies, it does not inspire confidence that molecular clocks are reliable. There is a huge amount of data behind it, but little evidence that the algorithms are actually reliable and inadequate effort given to data verification for the calibration points.
Also, there are some common sense checks that are missing. Larger clades are not necessarily reported as older than their subclades, for example.
Likewise, the OneZoom tree no doubt is reflecting data deficiencies in some of its strange groups within Mollusca. But it has some claimed groupings that are wrong, rather than merely a jumble of unknowns. I haven’t had time to dig and figure out where the problems are that lead to putting a pulmonate land snail in Vetigastropoda (on time divergence, about like putting a mammal in as a shark). But there is conspicuously no one involved that knows much about mollusks.
The difficulty is that the presentations claim to be authoritative without taking responsibility for data quality. If I quit my job and quit doing my research, I could contribute a lot of corrections to such sites, but there are some practical difficulties relating to staying fed and having access to the literature with no income.
