From:    Kathleen Hunt
To:      All                                    Msg #166, Oct-06-93 03:30PM
Subject: Turtle ancestors identified

Organization: University of Washington, Seattle
From: jespah@carson.u.washington.edu (Kathleen Hunt)
Message-ID: <28vke6$jqt@news.u.washington.edu>
Newsgroups: talk.origins

The Sept 24, 1993 issue of Science has an article about turtle evolution.
Turtles have long been a puzzle in paleontology, because they seemed to
appear suddenly in the fossil record, with complete turtle shells even on
the first known turtle fossils.  This article is a re-analysis of
pareiasaurs, large armored herbivorous reptiles from the late Permian.
They share 16 derived characters with turtles (13 of which are absent in
all other basal amniotes) and appear to be turtles' closest relatives.

Pareiasaurs had longitudinal rows of bony plates on the back, flanks, and
sometimes the belly.  Based on the proposed realignment of pareiasaurs
with turtles, it seems likely that these plates are the precursor of the
turtle shell.

The paper is:
Lee, M.S.Y.  1993.  The origin of the turtle body plan: bridging a famous
morphological gap.  Science 261:1716-1720.

Kathleen