Re: Genetic Study Shows Snake Evolution

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

David Marjanovic wrote-

> This is a sort of consensus tree, if I've understood it, of maximum
> likelihood, maximum parsimony, minimum evolution (isn't that a kind of
> maximum likelihood?) and Bayesian methods. Simplified here:
>
> +--turtle
> `--+--tuatara
>    `--Squamata
>         |--Dibamidae
>         `--+--Gekkonidae
>            `--+--+--Cordylidae
>               |  `--+--Xantusiidae
>               |     `--Scincidae
>               `--+--+--+--Teiidae
>                  |  |  `--Gymnophthalmidae
>                  |  `--+--+--Lacertidae
>                  |     |  `--Rhineuridae
>                  |     `--+--Bipedidae
>                  |       `--+--Amphisbaenidae
>                  |          `--Trogonophidae
>                  `--+--Anguimorpha
>                     |    |--+--Xenosauridae
>                     |    |  `--Varanidae
>                     |    `--+--Helodermatidae
>                     |       `--Anguidae
>                     `--+--Iguania
>                        |    |--Iguanidae
>                        |    `--+--Chamaeleonidae
>                        |       `--Agamidae
>                        `--Serpentes
>                             |--Scolecophidia
>                             `--Alethinophidia
>
> The topology within snakes looks rather normal -- according to what little
I
> know about snake phylogeny. (Iguania + Serpentes) has a bootstrap value
from
> maximum parsimony of 59 and a Bayesian posterior probability of 50. The
only
> big clades that have both values at 100 are Squamata and Serpentes. The
> basal 3 nodes within Squamata have very low values. In short... don't
trust
> that tree. :-)

Oh, I think that's a bit harsh.  What if we just trust the nodes of say...
>90% bootstrap?

|--Dibamidae
|--Gekkonidae
|  |--Lialis
|  `--Gekkoninae
|--Cordylidae
|--Xantusiidae
|--Scincidae
|  |--Eumeces
|  `--Tiliqua
|--Teidae
|  |--Gymnophthalmus
|  `--Teinae
|--Lacertidae
|--Rhineuridae
|--+--Bipedidae
|  `--+--Amphisbaenidae
|     `--Trogonophidae
|--Anguimorpha
|  |--Varanidae
|  |--Xenosauridae
|  |--Helodermatidae
|  `--Anguidae
|     |--Anniella
|     `--Diploglossinae
|--Iguanidae
|--Agamidae
|  |--Agaminae
|  `--Chameleoninae
`--Serpentes

Not completely useless, and does its job at falsifying the pythonomorph
hypothesis (assuming mosasaurs are anguimorphs).  Not that I wouldn't like
even larger datasets, as always.

Mickey Mortimer