WorksheetCreatedBy:CaliTurnerOceanConnectors2011

www.oceanconnectors.org 

ObservingaSeaTurtlefromtheEasternPacific

Description:Inthistwo‐partactivity,youwillobservealiveseaturtleinordertoidentifythespeciesofthisseaturtle,andcompareittoanancient,extinctmarineturtle.PartA–SeaTurtleSpeciesIdentificationTherearesevenspeciesofseaturtlesintheworld.FiveofthesespeciesarefoundontheEasternsideofthePacificOcean–alongthecoastofMexicoandCalifornia.Todayyouwillobserveoneoftheseturtlesandmakeobservationsaboutitsphysicalappearancebymakinguseofaspecialidentificationroadmapcalleda“dichotomouskey”.Reviewthediagrambelow,andthenusethedatatableprovidedtorecordyourobservations.Afterrecordingyourobservations,usetheprovidedkeytoidentifythespeciesofseaturtle.ExternalAnatomyofaseaturtle(External=outside;Anatomy=partsofthebody)

Aseaturtle’sbottomshelliscalledthe“plastron”.

Top Shell / Carapace Costal

(lateral) scutes

Prefrontal scale Nuchal scute

Vertebral (central)

scutes

Marginal scutes

Front flipper

Rear flipper

Imagesadaptedfrom:Pritchard,P.andMortimerJ.,Taxonomy,externalmorphology,andspeciesidentification,FoundIn: Eckert,K.L.,Bjorndal,K.A.,Abreu‐Grobois,F.A.,Donnelly,M.Eds,ResearchandManagementTechniquesfortheConservationofSeaTurtles.IUCN/SSCMarineTurtleSpecialistGroupPublicationNo.4.235pp.;1999,p.21‐38.

WorksheetCreatedBy:CaliTurnerOceanConnectors2011

www.oceanconnectors.org 

ObservationDataTable

Initialobservationsaboutturtle:(size,carapacecolor,plastroncolor,whatistheturtledoing?othernotes)

ExternalAnatomy Whattolookfor

Recordyourresponsesinthiscolumn,alongwithanyadditionalobservations

Carapace

AppearsHardorSoft?

Coloring?

VertebralScutes Howmany?

CostalScutes Howmanyoneachside?

NuchalScute

Doesittouchthecostalscutes?

MarginalScutes

Howmanyoneachside?

PrefrontalScales Howmany?

UsetheprovidedSeaTurtleIdentificationKeyandyourrecordedobservationstocorrectlyidentifythespeciesofseaturtleandanswerthequestionbelow.Whatspeciesistheturtle?_____________________________ ___________________________ CommonnameScientificnameWhatinformationfromyourSeaTurtleIdentificationKeysupportsthistheory?

WorksheetCreatedBy:CaliTurnerOceanConnectors2011

www.oceanconnectors.org 

PartB–MeetanAncientSeaTurtleSpeciesThesevenspeciesofseaturtlesshownonthedichotomouskeyusedforPartAarecalled“extant”speciesbecausetheyarestillalive.Speciesthatarenolongerlivingarecalled“extinct”.Millionsofyearsago,therewereotherspeciesofseaturtlesswimmingintheworld’soceans.Someoftheseancient,nowextinct,seaturtleswerehuge!LookingatthepicturesbelowofArchelon,recordsimilaritiesanddifferencesbetweenthisextinctturtle,andtoday’sextantturtles,liketheoneyousawrecently.Thentheorizeaboutwhythesechangesmayhaveoccurred.Similaritiesbetweenextinctandextantseaturtles:Differencesbetweenextinctandextantseaturtles:Inwhatwayshaveseaturtleschangedoverthepast100millionyears?Whydoyouthinkseaturtleshaveneededtoadaptovertime?

WorksheetCreatedBy:CaliTurnerOceanConnectors2011

www.oceanconnectors.org 

MeetArchelon,thelargestprehistoricturtlethateverlived;about15ftlongfromheadtotail

Images adapted from Jeffrey A. Seminoff and other sources as noted. © 2005 Encyclopedia Britannica,

Inc. 

Archelon

1st “turtle like” reptile