http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Molecular systematics and biogeography of the New World turtle genera Trachemys and Kinosternon
xii, 149 leaves : illustrations ; 28 cm.
The order Testudines has evolved to include a diverse array
of taxa that inhabit freshwater, marine, and terrestrial
ecosystems. The most widely accepted classification scheme
divides the turtles into two suborders: Pleurodira and
Cryptodira. These suborders are further divided into 13
families with 88 genera and 256 species. Extensive
morphological diversity among turtles has led to a vast array
of hypothesized phylogenies based on a wide variety of
methodologies, however no current phylogeny is universally
accepted. The present study addresses turtle relationships
using mitochondrial DNA sequence data. Over 230 taxa
representing all extant families were examined for a total of
250,000 basepairs. The mtDNA data support much of the
previous research i.e., monophyly of turtle families and a
basal diversification into Pleurodires and Cryptodires.
However, hypothesized sister relationships between snapping
and big headed turtles and either the Old World pond turtles
or tortoises and the New World pond turtles are not evident.
Instead, the sequence data supports a close relationship
between the Old World pond turtles and tortoises. A novel
finding of this study is a delineation between a primitive
(Trionychidae and Carettochelyidae) and an advanced clade
(all remaining families) within the Cryptodira. Finally,
the biogeography of the broadly distributed New World
families Kinosternidae and Emydidae was examined. These two
groups were chosen because of the potential insights they may
bring to the biogeography of this region. Each family has
had North America proposed as their point of origin and,
although this study confirms the Emydidae as North American,
Central America is confirmed as the point of origin for the
Kinosternidae. The radiation of the Emydid genus Trachemys
across North, Central, and South America and the Caribbean
appears to have occurred rapidly >10 million years ago. The
I<inosternidae appear to be much older and migrated northward
and southward out of Central America and Mexico. This
migration resulted in two expansions into North America and
two separate expansions into South America.
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 113-131.