Re: Big Bad Bolide vs. Evil Ecological Encrouching (was KT Boundary)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Jura" <archosaur@reptilis.net>

> True sea turtles (the flippered kind :) first appeared in the late
Jurassic and peaked in the Cretaceous. Their were quite a few different
families then (though Desmatochelyidae is the only coming to mind). I don't
remember if the other families went extinct before or after the K/T event.
Unfortunately I'm strapped for time right now. Anyone else care to lend a
hand here :)

The Tree of Life http://tolweb.org/tree?group=Testudines&contgroup=Amniota
says "The Plesiochelyidae is an extinct late Jurassic to early Cretaceous
radiation of marine turtles. This is a separate marine radiation from the
one to which living sea turtles belong". The adjacent molecular phylogeny
page
http://tolweb.org/tree/eukaryotes/animals/chordata/testudines/testudines.mol
lichen.html confirms that "[t]he two marine turtle families
(Dermochelyidae+Cheloniidae) are clearly a natural group, the Chelonioidea".
Chelonioidea is here
www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Reptilia/Pa
rareptilia/Polycryptodira.htm and includes the Cretaceous group
Protostegidae (which includes *Archelon*) and Desmatochelyidae, both closely
related to the living leatherback turtle *Dermochelys* (click
Dermochelyoidea). Plesiochelyidae is outside Polycryptodira (click... on?
at? its root). IIRC its sister group Eurysternidae was amphibious.
Unfortunately there are no time ranges given on these pages.
        The land turtle family Baenidae, endemic to North America, survived
the K-T only to die out in (at the end of?) the Eocene.