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Re: Condylarths (TINGAMARRA REVISITED)
In a message dated 5/18/01 8:24:11 PM, email@example.com writes:
<< I'm not clear on this. How so? >>
Okay, at some time during the late Cretaceous, there was one single animal
that had a functioning trophoblast, thereby allowing for true placental
reproduction [some bilbies in Australia have placentas]. This critter's
descendants included the protoungulatae, which were once a single species.
During the Lancian (just before the K-T boundary) there began a major phase
of speciesization in the "condylartha," the survivors of which evolved into
the various ungulata we know today.
In other words, during the Cretaceous, the Ungulata went from a single
species to small number of closely related species. They evolved into many
directions, and those survivors are the crown groups we know and love today.
In fact during the Paleocene and earliest Eocene, the ungulates were a
relatively homogeneous group.
<<But since a sparrow doesn't really look like a T. rex,
there must be a deeper basis for the actual
relationship other than what might just be a
superficial similarity, yes?>>
Well, since both had a common ancestor in the middle Triassic.....
<<(Or maybe I'm confused. What do you mean by
Okay, a tuatara "looks like" an iguana. Simple, no?
<<(What was a condylarth supposed to look like and how
do you know it was supposed to look like that?)>>
As you well know, there are lots of paleontological reconsructions. Since
you're a dino fan, you probably ignored those of the early placentals of the
lancian and Paleocene, but must have read that the mammals of the time
resembled modern rodents, and a hyrax looks like a guinea pig. [I know this
for a fact as I've seen both close up.]
Therefore, looking at the modern hyrax and the reconstructions of early
ungulates, we can conclude that the modern hyrax looks like an early
ungulate, a condylarth. GET IT NOW?