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Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan

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The Project Gutenberg EBook of Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan, by William A. Clemens This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.net Title: Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan Author: William A. Clemens Release Date: October 20, 2009 [EBook #30297] Language: English Character set encoding: ISO-8859-1 *** START OF THIS PROJECT GUTENBERG EBOOK FOSSIL MAMMAL SINCLAIRELLA *** Produced by Chris Curnow, Joseph Cooper, Diane Monico, and the Online Distributed Proofreading Team at http://www.pgdp.net UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY Volume 14, No. 17, pp. 483-491, 2 figs. March 2, 1964 Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan BY WILLIAM A. CLEMENS, JR. UNIVERSITY OF KANSAS LAWRENCE 1964 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Theodore H. Eaton, Jr. Volume 14, No. 17, pp. 483-491, 2 figs.
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The Project Gutenberg EBook of Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan, by William A. Clemens
This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.net
Title: Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan
Author: William A. Clemens
Release Date: October 20, 2009 [EBook #30297]
Language: English
Character set encoding: ISO-8859-1
*** START OF THIS PROJECT GUTENBERG EBOOK FOSSIL MAMMAL SINCLAIRELLA ***
Produced by Chris Curnow, Joseph Cooper, Diane Monico, and the Online Distributed Proofreading Team at http://www.pgdp.net
UNIVERSITYOFKANSASPUBLICATIONS MUSEUMOFNATURALHISTORY
Volume 14, No. 17, pp. 483-491, 2 figs. March 2, 1964
Records of the Fossil Mammal
Sinclairella, Family Apatemyidae,
From the Chadronian and Orellan
BY
WILLIAM A. CLEMENS, JR.
UNIVERSITYOFKANSAS LAWRENCE 1964
UNIVERSITYOFKANSASPUBLICATIONS, MUSEUMOFNATURALHISTORY
Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Theodore H. Eaton, Jr.
Volume 14, No. 17, pp. 483-491, 2 figs. Published March 2, 1964
UNIVERSITYOFKANSAS Lawrence, Kansas
PRINTED BY HARRY (BUD) TIMBERLAKE, STATE PRINTER TOPEKA, KANSAS 1964
29-8587
Records of the Fossil Mammal Sinclairella, Family Apatemyidae, From the Chadronian and Orellan
BY WILLIAM A. CLEMENS, JR.
Introduction
THEFAMILYAPATEMYIDAEHASALONGGEOCHRONOLOGICALRANGEINNORTHAMERICA, BEGINNINGINTHE TORREJONIANLAND-MAMMALAGE,BUTISREPRESENTEDBYA RELATIVELYSMALLNUMBEROFFOSSILSFOUNDATAFEWLOCALITIES. TWOFOSSILSOF ORELLANAGE,FOUNDINNORTHEASTERNCOLORADOANDDESCRIBEDHERE,DEMONSTRATE THATTHEGEOCHRONOLOGICALRANGEOFTHEAPATEMYIDAEEXTENDSINTOTHE MIDDLE OLIGOCENE. ISOLATEDTEETHOFSinclairella dakotensisJEPSEN,PARTOFASAMPLEOF A CHADRONIANLOCALFAUNACOLLECTEDBYFIELDPARTIESFROMTHE WEBB SCHOOLOF California, are also described.
ITHANKMR. RAYMONDM. ALF, WEBBSCHOOLOFCALIFORNIA, CLAREMONT, CALIFORNIA,AND DR. PETER ROBINSON, UNIVERSITYOF COLORADO MUSEUM, BOULDER, COLORADO,FORPERMITTINGMETODESCRIBETHE FOSSILSTHEYDISCOVERED. ALSODR. ROBINSONMADEAVAILABLETHEDRAFT OFASHORTPAPERHEHADPREPAREDONTHETOOTHFOUNDIN WELD COUNTY, COLORADO;HISWORKWASFACILITATEDBYAGRANTFROMTHE UNIVERSITYOF COLORADO COUNCILON RESEARCHAND CREATIVE WORK. I ALSOGRATEFULLYACKNOWLEDGERECEIPTOFCRITICALDATAANDVALUABLE COMMENTSFROM DRS. EDWING C. ALBREATH, GLENNJ L. EPSEN,AND MALCOLM C. MCKENNAWHOISCURRENTLYREVISINGTHE PALEOCENE APATEMYIDSANDSTUDYINGTHEPHYLOGENETICRELATIONSHIPSOFTHE FAMILY. THEPREFIXESOFCATALOGUENUMBERSUSEDINTHETEXTIDENTIFY fossils in the collections of the following institutions: KU, Museum of NATURAL HISTORY, THE UNIVERSITYOF KANSAS, LAWRENCE; PRINCETON, PRINCETON MUSEUM, PRINCETON, NEW JERSEY; RAM-UCR, RAYMOND ALFMUSEUM, WEBBSCHOOLOFCALIFORNIA, CLAREMONT, CALIFORNIA(THE PERMANENTREPOSITORYFORTHESESPECIMENSWILLBETHEUNIVERSITYOF CALIFORNIA, RIVERSIDE);AND UCM, UNIVERSITYOF COLORADO MUSEUM, BOULDER, COLORADO. THESYSTEMOFNOTATIONSFORTEETHPRESCRIBEDFOR USEHEREISASFOLLOWS:TEETHINTHEUPPERHALFOFTHEDENTITIONARE DESIGNATEDBYACAPITALLETTERANDANUMBER;THUSM2ISTHENOTATION FORTHEUPPERSECONDMOLAR;TEETHINTHELOWERHALFOFTHEDENTITION AREDESIGNATEDBYALOWER-CASELETTERANDANUMBER;THUSP2ISTHE notation for the lower second premolar.
Family Apatemyidae Matthew, 1909
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Genus Sinclairella Jepsen, 1934 Sinclairella dakotensis Jepsen, 1934
THETYPEOFTHESPECIES, PRINCETONNO. 13585,WASDISCOVEREDIN CHADRONIAN STRATAOFTHEUPPERPARTOFTHE CHADRON FORMATIONCROPPINGOUTIN BIG CORRAL DRAW,APPROXIMATELY 13MILESSOUTH-SOUTHWESTOF SCENIC,INSOUTHWESTERN SOUTH DAKOTA (JEPSEN, 1934,P. 291). DETAILEDDESCRIPTIONSOFTHETYPE SPECIMENAREGIVENINPAPERSBYJEPSEN(1934)ANDSCOTTANDJEPSEN(1936). Isolated teeth of Chadronian age referable toSinclairella dakotensisHAVEBEEN DISCOVEREDSUBSEQUENTLYATALOCALITYIN NEBRASKAANDFOSSILSOF ORELLANAGE, ALSOREFERABLETOS. dakotensis,HAVEBEENCOLLECTEDATTWOLOCALITIESIN Colorado. The sample from each locality is described separately.
Sioux County, northwestern Nebraska
Material.—RAM-UCRNOS. 381,LEFT598, M1; LEFTM2; 1000,RIGHT M1; 1001,RIGHTM2; 1079,RIGHTM2; 1674,RIGHT M2;AND 3013,LEFT m2.
Locality and stratigraphy.—THESE CHADRONIANFOSSILSWERE DISCOVEREDBY RAYMOND ALFANDMEMBERSOFHISFIELDPARTIESIN SEVERALHARVESTERANTMOUNDSBUILTINEXPOSURESOFTHE CHADRON FORMATIONIN SEC. 26, T 33 N, R 53 W, SIOUX COUNTY, NEBRASKA (ALF, 1962,ANDHOUGHANDALF, 1958). THISISUCRLOCALITYV5403. THECOLLECTORSCAREFULLYCONSIDEREDTHEPOSSIBILITYTHATSOMEOFTHE FOSSILSFOUNDINTHEANTMOUNDSWERECOLLECTEDFROMYOUNGERSTRATA BYTHEHARVESTERANTSANDCONCLUDEDTHISWASUNLIKELY(ALF,PERSONAL communication).
Description and comments.—THECUSPSOF RAM-UCRNO. 381,A LEFTM1,ARESHARPANDTHEWEAR-FACETSRESULTINGFROMOCCLUSIONWITH THELOWERDENTITIONARESMALL. THEPARACONULEISALOW,ILL-DEFINED CUSPONTHEANTERIORMARGINOFTHECROWN;AMETACONULEISNOT PRESENT. ASMOOTHSTYLARSHELFISPRESENTLABIALTOTHEMETACONE. THECROWNWASSUPPORTEDBYTHREEROOTS. THEREARENO interradicular crests.
THECROWNOF RAM-UCRNO. 1674,ARIGHT M2,ISHEAVILYABRADED ANDMANYMORPHOLOGICALDETAILSOFTHECUSPSHAVEBEENDESTROYED. LOWINTERRADICULARCRESTSLINKEDTHETHREEROOTSOFTHETOOTHWITHA LOW,CENTRALPROMINENCE. ASWASTHECASEWITHRAM-UCRNO. 381, NOSIGNIFICANTDIFFERENCESCOULDBEFOUNDINCOMPARISONSWITH illustrations of the teeth preserved in Princeton no. 13585.
RAM-UCRNOS. 598, 1001, 1079,AND3013ALLAPPEARTOBEM2'S. THETALONIDSOFTHESETEETHARENOTELONGATED,THEIRTRIGONIDSHAVE QUADRILATERALOUTLINES,ANDTHEPARACONIDSARESMALLBUTPROMINENT, BLADELIKECUSPS. THETRIGONIDOFRAM-UCR 1000ISELONGATEDAND THEPARACONIDISAMINUTECUSP;THETOOTHCLOSELYRESEMBLESTHEM1 of the type ofSinclairella dakotensis.
Logan County, northeastern Colorado
Material.—KUNO. 11210 (FIG. 1),AFRAGMENTOFALEFTMAXILLARY containing P4 and M1-2.
Locality and stratigraphy.—THEFOSSILWASFOUNDINTHECENTEROFTHE W-1/2, Sec. 21, T 11 N, R 53 W, Logan County, Colorado, " ... in the BEDBELOWAgnotocastorBED, CEDARCREEKMEMBER...." (RONALDH. PINE, 1958,FIELDNOTESONFILEATTHEUNIVERSITYOFKANSAS). THEBED SODEFINEDISPARTOFUNIT3INTHELOWERDIVISIONOFTHECEDARCREEK MEMBER,ASSUBDIVIDEDBY GALBREATH (1953:25)INSTRATIGRAPHIC section XII. The fauna obtained from unit 3 is of Orellan age.
[Pg 487]
Fig. 1. Sinclairella dakotensis Jepsen, KU no. 11210, fragment of left maxillary with P4 and M1-2; Orellan, Logan County, Colorado; drawings by Mrs. Judith Hood: a, labial view; b, occlusal view; both approximately × 9.
Description and comments.—P4OF KUNO. 11210HASALARGE POSTEROLINGUALCUSPSEPARATEDFROMTHEMAINCUSPBYADISTINCT GROOVE,WHICHDEEPENSPOSTERIORLY. THEPOSTEROLINGUALCUSPIS SUPPORTEDBYTHEBROADPOSTERIORROOT. P4OFTHETYPESPECIMENOF Sinclairella dakotensisISDESCRIBED (JEPSEN, 1934,P. 392)AS HAVINGANOVALOUTLINEATTHEBASEOFTHECROWN,ANDASMALL, POSTEROLINGUALCUSP. ACHIPOFENAMELISMISSINGFROMTHEPOSTERIOR SLOPEOFTHEMAINCUSPOFTHE P4OF KUNO. 11210. THEANTERIOR SLOPEOFTHEMAINCUSPISFLATTENED,POSSIBLYTHERESULTOFWEAR,AND THEREISNOEVIDENCEOFAGROOVELIKETHATPRESENTONTHEP4OFTHE type specimen.
ONLYAFEWDIFFERENCESWEREFOUNDBETWEENTHEMOLARSPRESERVEDIN KUNO. 11210ANDTHEIRCOUNTERPARTSINTHETYPESPECIMEN. ASTYLAR SHELFISPRESENTLABIALTOTHEMETACONEOFM1OFKUNO. 11210,BUT, UNLIKETHETYPE,ITSSURFACEISSMOOTHANDTHEREISNOEVIDENCEOF CUSPS. OFTHETHREESMALLSTYLARCUSPSONTHESTYLARSHELFOFM2THE SMALLESTISINTHEPOSITIONOFAMESOSTYLE. THE M2LACKSACHIPOF ENAMELFROMTHELINGUALSURFACEOFTHEHYPOCONE. UNLIKETHEM2OF PRINCETONNO. 13585,INOCCLUSALVIEWTHEPOSTERIORMARGINOFTHE M2OF KUNO. 11210ISCONVEXPOSTERIORTOTHEMETACONE. THE ANTERIOREDGEOFTHEBASEOFTHEZYGOMATICARCHOF KUNO. 11210 WASDORSALTO M2. THESHALLOWOVALDEPRESSIONINTHEMAXILLARY dorsal to M1 might be the result of post-mortem distortion.
THEMOLARSPRESERVEDINKUNO. 11210ANDTHEIRCOUNTERPARTSINTHE TYPESPECIMENDONOTAPPEARTOBESIGNIFICANTLYDIFFERENTINSIZE (TABLE1)ORMORPHOLOGYOFTHECUSPS. THEONLYDIFFERENCEBETWEEN THETWOSPECIMENSTHATMIGHTBEOFCLASSIFICATORYSIGNIFICANCEISTHE DIFFERENCEINSIZEOFTHEPOSTEROLINGUALCUSPOFA P4. TPRESENTTHE RANGEOFINTRASPECIFICVARIATIONINTHEMORPHOLOGYOF P4HASNOT BEENDOCUMENTEDFORANYSPECIESOFAPATEMYID. THEEVOLUTIONARY TRENDORTRENDSOFTHEAPATEMYIDS MCKENNA, 1960,P. 48FOR
[Pg 488]
PROGRESSIVEREDUCTIONOFFUNCTIONOFP4PROBABLYWEREPARALLELEDBY SIMILARTRENDSINTHEEVOLUTIONOFTHEI P4. FSO,THEINTRASPECIFIC VARIATIONINTHEMORPHOLOGYOF P4COULDBEEXPECTEDTOBE SOMEWHATGREATERTHANTHATOFTHEUPPERMOLARS,FOREXAMPLE. THE MORPHOLOGICALDIFFERENCEBETWEENTHE P4'SOFTHETYPEOF Sinclairella dakotensisANDKUNO. 11210ISNOTEXTREMEANDDOES NOTEXCEEDTHERANGEOFINTRASPECIFICVARIATIONTHATCOULDBE EXPECTEDFORTHISELEMENTOFTHEDENTITION. THECLOSERESEMBLANCES INSIZEANDMORPHOLOGYBETWEENTHEM1-2OFPRINCETONNO. 13585 ANDKUNO. 11210ALSOFAVORIDENTIFICATIONOFTHELATTERASPARTOFA member of an Orellan population ofSinclairella dakotensis.
Weld County, northeastern Colorado
Material.—UCMNO. 20173 (FIG. 2),ISA right M2.
Locality and stratigraphy.—The TOOTHWAS DISCOVEREDATTHE MELLINGERLOCALITY, SEC. 17, T 11 N, R 65 W, WELDCOUNTY, COLORADO. THE MELLINGERLOCALITYIS INTHE CEDAR CREEK MEMBER, WHITE RIVER FORMATION, ANDITSFAUNAIS CONSIDEREDTOBEOF ORELLANAGE (PATTERSONAND MCGREW, 1937,AND Galbreath, 1953). Fig. 2. Sinclairella dakotensis Jepsen, UCM Description and no. 21073, right M2; Orellan, Weld County, comments.—UCM Colorado; drawing by Mrs. Judith Hood: NO. 21073,WHICHIS occlusal view, approximately × 9. MOREHEAVILY ABRADEDTHAN KU no. 11210, shows no evidence of a stylar cusp either anterolabialTO THEMETACONEORINTHEPOSITIONOFAMESOSTYLE. ASMALLSTYLARCUSP ISPRESENTANTEROLABIALTOTHEPARACONE. ANOTCHTHATAPPEARSTO HAVEBEENCUTTHROUGHTHEENAMELOFTHEPOSTEROLABIALCORNEROFTHE CROWNCOULDHAVERECEIVEDTHEPARASTYLARAPEXOF M3. ASIMILAR NOTCHISNOTPRESENTONTHEM2OFKUNO. 11210NORINDICATEDINTHE ILLUSTRATIONSOFTHE M2OF PRINCETONNO. 13585. THECORONAL DIMENSIONSOF UCMNO. 21073 (TABLE 1)DONOTAPPEARTODIFFER SIGNIFICANTLYFROMTHOSEOFTHE M2'SOF KUNO. 11210ANDTHETYPE specimen ofSinclairella dakotensis.
Comments
WITHTHEDISCOVERYOF ORELLANAPATEMYIDSTHEGEOCHRONOLOGICALRANGEOFTHE FAMILYIN NORTHAMERICAISSHOWNTOEXTENDFROMTHE TORREJONIANTHROUGHTHE ORELLANLAND-MAMMALAGES. THEDISCOVERIESREPORTEDHEREENLARGETHE OLIGOCENERECORDOFAPATEMYIDSTOINCLUDENOTONLYTHETYPESPECIMENOF Sinclairella dakotensis,ASKULLANDASSOCIATEDMANDIBLEFROM SOUTH DAKOTA, BUTALSOSEVENISOLATEDTEETH,REPRESENTINGATLEASTTWOINDIVIDUALS,FROMA CHADRONIANFOSSILLOCALITYIN NEBRASKAANDONESPECIMENFROMEACHOFTWO ORELLANFOSSILLOCALITIESINNORTHEASTERN COLORADO. SIMPSON (1944:73,AND 1953:127)PRESENTEDTABULATIONSOFTHEPUBLISHEDRECORDSOF AMERICAN APATEMYIDSANDSUGGESTEDTHEDATAINDICATEDTHEPOPULATIONSOFTHESE MAMMALSWEREOFSMALLSIZETHROUGHOUTTHEHISTORYOFTHEFAMILY. THEFEWPRE-OLIGOCENEOCCURRENCESOFAPATEMYIDSDESCRIBEDSUBSEQUENTLY(NOTEMCKENNA, 1960,FIGS. 3-10,ANDP. 48)ANDOCCURRENCESDESCRIBEDHERETENDTOREINFORCE SIMPSON'SINTERPRETATION. THISINTERPRETATIONMAYHAVETOBEMODIFIEDTOSOME DEGREE,HOWEVER,WHENCURRENTSTUDIESOFCOLLECTIONSOFPRE-OLIGOCENE apatemyids are completed (McKenna, personal communication).
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