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Avian phylogeny (1 Viewer)

jts1882

Well-known member
United Kingdom
He's just taking an idea and seeing how it works out.

The next step should be making adjustments for the family cut off, using some metric based on mutation rate or generation length. Using different cutoffs I get the following family numbers in Passeriformes

  • 35mya (his): 7 families
  • 30mya: about 20 families
  • 25mya: about 40 families
  • 20mya: about 70 families
  • Current: 144 families (IOC), 136 (H&M4)

Applying manageable chunk theory, I'd say a system using 20 mya and 70 families might be able to get some traction. Anything less and the Passeridae becomes too large to be a useful classification. There is also tradition. Halving the the number of families would get enough resistance, anything more and they'd be storming the citadel.
 

Mysticete

Well-known member
United States
Not sure why there is doubling-down on these set increments (arbitrarily chosen outside of the order level) and the insistence they apply universally across all birds. My take away from the last tree was that the specific approach described above was obviously broken.
 

Mysticete

Well-known member
United States
He's just taking an idea and seeing how it works out.

The next step should be making adjustments for the family cut off, using some metric based on mutation rate or generation length. Using different cutoffs I get the following family numbers in Passeriformes

  • 35mya (his): 7 families
  • 30mya: about 20 families
  • 25mya: about 40 families
  • 20mya: about 70 families
  • Current: 144 families (IOC), 136 (H&M4)

Applying manageable chunk theory, I'd say a system using 20 mya and 70 families might be able to get some traction. Anything less and the Passeridae becomes too large to be a useful classification. There is also tradition. Halving the the number of families would get enough resistance, anything more and they'd be storming the citadel.
I think the best approach is to just develop, below the order level, different benchmarks for different major categories. We shouldn't work on the assumption that all birds are evolving at the same rate and responding to the same environmental changes/disturbances in the exact same way.
 

jurek

Well-known member
We shouldn't work on the assumption that all birds are evolving at the same rate and responding to the same environmental changes/disturbances in the exact same way.

This is in principle true... but implies two things to be used for taxonomy:
1. What is 'evolved enough' or 'different' implies having some objective measure of evolution to treat as a reference. So far, genetic distance is the only one. Without any reference, it is just say-so and toss of a coin is just as good.
2. If you propose using different references for different subgroups, then you need to propose a second objective criterion when to use the same / other reference. Without this, the effort again becomes a say-so and a toss of a coin.
 

Xenospiza

Distracted
Supporter
All the "new" 9-primary oscine families and all the "new" warbler/babbler families could well be scrapped again --- I wouldn't shed a single tear.

I am not as drastic as Jurek in my avian family reduction demands, but the last few years have just been silly!
 

D Halas

Well-known member
This is in principle true... but implies two things to be used for taxonomy:
1. What is 'evolved enough' or 'different' implies having some objective measure of evolution to treat as a reference. So far, genetic distance is the only one. Without any reference, it is just say-so and toss of a coin is just as good.
2. If you propose using different references for different subgroups, then you need to propose a second objective criterion when to use the same / other reference. Without this, the effort again becomes a say-so and a toss of a coin.

You're never going to have an objective criterion of the kind you're calling for, because genera, families, orders and so on aren't real entities. There are all kinds of criteria you can choose to use for delineation of higher groups, and some will turn out to be more useful and produce more "natural-looking" groups than others, but there's no way to eliminate some element of subjectivity.
I can give you a criterion that's perfectly objective in the way you ask for in your second point, for example, that would be completely useless in reality: Divide up all clades into reciprocally-monophyletic groups so that no genus has more than ten members, no family has more than 100 members, no order has more than 1000 members, and so on. Given an accepted phylogeny, the application of this criterion would be perfectly objective, but it would also be completely useless, dividing up lots of speciose groups for no useful purpose. On the other hand, the seemingly arbitrary way we divide clades up now, based somewhat on genetic distances, but also on the degree of morphological similarity within a group compared to across groups, gives us much more useful delineations for genera, families, and orders.
 

Acanthis

Well-known member
Question...Pinarornis was recently moved to Turdidae based on the below work

The Largest Avian Radiation. The Evolution of Perching Birds, or the Order Passeriformes / [Eds] J. Fjeldså, L. Christidis & P.G.P.Ericson, Barcelona: Lynx Edicions , 2020

I don't have access to this book, but can anyone describe the specific phylogenetic position? Is it embedded within Myadestinae or Turdinae, or sister to both?

In their Myadestinae, alongside Stizorhina and Neocossyphus in a sister clade to Myadestes.
Mentioned in the text as from "M. Irestedt, unpubl. DNA sequence"

Interestingly Sialia & Grandala are left separate (and unranked) from both Turdinae and Myadestinae in the classification and form the earliest split in the Turdid lineage. In appendix 2 which has the dated phylogenetic trees, the Bluebird/Grandala lineage diverged at around 25-27mya!!
Apparently this is just a little older than the Mimidae/Sturnidae split. o_O
The bluebirds and grandala split itself is pretty old, dated at around 22 mya!!
 
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