[Taxacom] Dawwinius media hype (and relationships)

[John Grehan]

 -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
> Sent: Wednesday, May 20, 2009 10:55 PM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Dawwinius media hype (and relationships)
> 
> Dear All,
>      The earliest members of Order Primatiformes (plesiadapiforms) no
> doubt had  clawed hands, any one of which (or combination of which)
> could have been used for grooming.  As claws evolved into nails, only
> some of the claws were retained for grooming (or other uses).
Tarsiers
> still retain two such grooming claws, while lemurs and relatives only
> retain one such claw.

The presence of at least one grooming claw represents a potential
synapomorphy of lemurs/lorises and tarsiers

>        I really don't see how the loss of grooming claws (or absence
of
> toothcombs) can be seriously regarded as evidence for Darwinius being
> directly related to haplorhines.  In fact, if Darwinius was truly a
> primitive member of Haplorhini, I would tend to expect it to have two
> grooming claws like tarsiers!!!  

It might depend on whether the two claw condition is primitive or
derived in tarsiers.

It makes me wonder if the authors of
> the Darwinius paper have unconsciously cherry-picked a few characters
> which seem to support their preconceived notions of how adapoids fit
> into the evolutionary tree of primates (and therefore have a bias that
> would tend to make them find fault with characters which would dispute
> their conclusions).  Their simplistic "cladogram" is far from being a
> real cladistic analysis.

Agreed. The interrelationships of prosimians, tarsiers, and anthropoids
are problematic, let along various fossil taxa that are incomplete and
do not represent soft tissue features that are critical for assigning
living taxa.

>         If Darwinius split off before the Haplorhini-Strepsirhini
> divergence, or lies at the base of Haplorhini, it has great
significance
> in the line leading to humans.  

If the Haplorhini (tarsiers-anthropoids) is a valid group.


However, if it is a deadend
> strepsirhine, then these authors had better enjoy their 15 minutes of
> fame before the media turns on them.  

Are strepsirhine's really a dead-end group?

John Grehan