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Mammals & Climate
Russell W. GrahamEarth & Mineral Sciences
MuseumPennsylvania State University
University Park, PA [email protected]
Vertebrate fossil collection
A volunteer excavates around a mammoth vertebra at the Pratt Mammoth site, KSboneblogger.com/mapping-the-pratt-mammoth-excavation-using-gps-and-basic-surveying-technology
Megafauna collection Microfossil collection
Excavating & bagging sediment with bones
Screen washingSediment for bones
Picking screenwashConcentrate for bones
Why Mammals
Abundant sites and specimens with electronic databasesExcellent Geographic CoverageCan directly date individual specimensSmall mammals can not migrate (local environment)Can be identified to generic and frequently species levelEcology of modern forms well studied so good proxieshttp://www.mnh.si.edu/mna/about.cfm
Many taxa are limited to specific habitats
Databases
http://www.neotomadb.org/
http://www.ucmp.berkeley.edu/miomap/
Accuracy and Precision of AMS Radiocarbon Dating Bone
From T. S. Stafford, Jr.
Individual specimens as small as rodent and insectivore skulls & jaws can be datedAnd in some cases even isolated teeth and Fragmentary bones can be dated accurately and precisely
From T. S. Stafford, Jr.
Identification of Shrews
Sorex palustris(water shrew)
Blarina brevicauda(short tailed shrew)
Cryptotis parva(least shrew)
Barren ground musk oxen (Ovibos moschatus)have specific physiological and anatomical adaptations for cold climates
Modern (shaded in inset) & Late Pleistocene (dots) distribution of the collared lemming (Dicrostonyx sp.) in North America
Summer pelage
Winter pelage
Modern environmentData from Neotoma Database
Morphological and physiologicalAdaptations for cold climates
Brown lemmings (Lemmus trimucronatus) have behavioral adaptations for cold climate
Subnivian environment protects the brown lemming from the cold.
Squirrels – Habitats – ClimateGrassland“Dry”
Forest“Moist”
--------------------------------------------------------
Prairie dog –-shortgrassCynomys
Thirteen line ground squirrel – short to tall grassSpermophilus tridecemlineatus
Franklin’s ground squirrel – tall grassSpermophilus franklinii
Woodchuck – grassy areas in forest-Marmota monax
Marmot – grassy area in coniferous forestor alpine tundra – Marmota flaviventris
Chipmunk –woodland –Tamias
Tree SquirrelsClosed Forest
Glaucomys
Tamiasciurus
Sciurus niger
Sciuruscarolinensis
Squirrels & Vegetation
No-analog Vegetation: Several Thousand Year
Intervals&
Extends into Holocene
Non-analog Mammals: 500 year intervals, extend throughout late Pleistocene & beyond, absent in Holocene
From Overpeck et al. 1992
Was there a continental-wide Clovis Drought?NO
Taxa Sites
WEST ------------------------------------------------------------ EASTLR-AZ AU-TX LF-SD KW-MO
Grassland/Dry/WarmBison sp. X XCamelops hesternus XMammuthus columbi X X XPerognathus sp. X XOnychomys leucopus XSpermophilus sp. XGeomys sp. X XSpermophilus franklini XSpermophilus tridecemlineatus X
Woodland/Forest/ Cool/MoistTapirus merriami XUrsus americanus XSynaptomys cooperi X XScalopus aquaticus X XBlarina sp. X XSorex palustris XSorex hoyi XClethrionomys gapperi XZapus princeps XMylohyus sp. XMammut americanum XMarmota monax XSciurus sp. X
Permanent WaterOndatra zibethica X X X XOsteichthyes X XMustela vison X
LR- Lehner Ranch, AZ; AU- Aubrey, TX; LF- Lange Ferguson, SD; KW-Kimmswick, MO• Selected Environmentally Sensitive Taxa from Clovis Sites
(Data derived from Neotoma Database)
Selected Environmentally Sensitive Taxa from Clovis Sites (Data derived from Neotoma Database)
