Jurassic Dinosaur Tracks and Trackways of the Cleveland Basin, Yorkshire 193
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E-f*u PROCEEDINGSOFTHE YORKSHIREGEOLOGICAL SOCIETY, ^l,' Jurassicdinosaur tracks and trackwaysof the Cleveland Basin,Yorkshire: preservation, diversity and distributio M. Rorr,reNoland M. A.Wuyrr, ' ( Presidentíaladdresses ileliyered at York,4th December1999, and 2nd December,2000) ' Depatunent oÍ Geogruphy Dainton Building, Btookhill, University of Shefield" Shefield 33 7HF (e-mail: m.romano@ shefield. ac. uk; m.o. w hyte@sheffiel d.ac.uk) SUMMARY:Dinosaur tracks are abundantin the Middle Jurassicrocks of Yorkshire and indeed characterizethe non-marine sequencesdeveloped vr'ithin the ClevelandBasin. These tracks and associatedtrackways provide valuableevidence of the possible diversity of the dinosaur communities,their potential makers and behaviour and useful insightsinto the habitats and palaeo- environmentduring the time of deposition.The uneven historical developmentof researchinto Yorkshire dinosaur tracks is reviewedand the Middle Jurassiclithostratigaphy, biostratigraphyand chronostratigraphyof the region is outlined. Next, the probablepalaeoenvironment of the Middle JurassicCleveland Basin, generally regarded as a coastalplain and fluvial complex,is briefly summarized.The terminologyused to descdbethe dominantpreservational types ofdinosaur tracks,such as surface, trans- mitted and underprints,is clearly defined,$,ith examplesfrom the Yorkshire sequences.Thè Yorkshire tracksshow considerable moryhologicaldiversity ard at pr€sent29 different morphotypeshave been recognized,which possiblyrepresent at least 15 ich- notaxa.These morphotypes include both quadrupedaland bipedal forms, as well as a distinctivesuite of raking prints resulting from swimmingactiyity, The distribution and abundanceof the known dinosaurtuacks within the Middle Jurassicrocks of York- shireis described.For the flrst time, a range cha of dinosaurtuacks is presentedthat illustratesthe persistenceof somemorpho- tlpes throughout the RavenscarGroup (Middle Jurassic)of the ClevelandBasin. Track distribution and diversity data allow reconstuuctionof the Yorkshiredinosaur communities that Ìveremade up ofbetween7-10 commontypes, belonging to sauropods, 'megatracksite' stegosaurids,ornithopods and theropods.The area is a of global importance. Dinosaur remainsfrom the Middle Jurassicof Yorkshire are the tacks. These persorlneland their contributions will be very rare (\{illiamson 1837;Fox-Strangways 1904; Benton identifiedbelow. 1996)and reflect the poor global record of the group at this Folìowinga brief historicalreview, an outline of the Middle time, pa icularly in the Aalenian (Romer 1966;Weishampel Jurassiclithostratigraphy, biostratigraphy and chronostratig- et al. 1990;Benton 1993).The singlereported find of bone raphy of the region will be presented;after which the Middle assignedto the sauropodCetiosaurus îrom the marine Scar- Jurassicpalaeoenvironment will be desqibed.Thenfollows an boroughFormation (Williamson 1837;Fox-Strangways 1904) account of the terminology used to describethe dominant still remainsthe only publishedoccurrence of dinosaurskele- preservationaltypes of dinosaurtracks encountered.Finally, tal elementsftom the Middle Jurassicof this area.However, three aspectsof the dinosaurtracks of Yorkshirewill be inves- dinosaurtracks and trackwaysarevery commonand thesecan tigated;track diversity,track distribution and àbundanceand provide valuable evidence of the possible diversity of the possibledinosaur divenity. Although in this review relatively dinosaurcommunities, their potential makersand behaviour, few of the tracks are named,this is not meant to signify an and ùseful ínsìghtsinto the palaeoenvironmentduring the aversionto this practice.Indeed, the naming of tracks allows time of deposition(Thulborn 1990;Lockley 1991r). easyleference tO any previouslynamed ichnite in the litera- Recent work on dinosaurprinls by the authorshas shown ture (McAllister 1989, p. a) and, by using the cu[ently that thereis a v/iderange ofprint morphotypesfrom the York- adopted'binomen' system based on the Linneanclassification, shire Middle Jurassicsuccession, which indicatesthe former may indicate close morphologicalsimilarity or dissimila ty. presenceof varied dinosaurcommunities (Whyte & Romano Howeyer, at this stage of these studies,in particular \ryith 798I,1993,1995,2Co1,2002;Romano & Whyte 1996;Romano referenceto the t dactyl hacks, it is preferential to identify el al 1999).As regular visitorsto the eastcoast over the past different unnamedmorphotypes that may, with more rrork, 15 yearswe,have produced a comprehensivedatabase on the becomethe basisof more formal ichnotaxa.This work on the variety and occurrenceof these ichnites.Extended detailed behaviourpatterns of thesedinosaurs, as deduced ftom track suryeysof th€ coastalexposures with volunteersftom Earth- morphology,configuralion of the trackwaysand habitats,\ryill watch Intemational started in 1996. These, together with be addressedat a later date. numerousgeological field excursionsand individual contri- butions ftom colleaguesand co-workers too numetous to mention, have also added to theserecords. More specifically, 1. HISTORICAL REVIEW OF TR-ÀCK RESEARCH a Dinosaur Track Research Group (DTRG) has been estabishedat the University of Sheffreld,which has overseen It is now nearly 100 yearssince definite dinosaurtracks were a number of PhD projects on field and laboratory stùdiesof first describedftom the Middle Júrassicrocks of Yorkshire (Brodrick 1907), the 'true staúing-point of British Jurassíc O Yorkshire GeologicalSociety, 2003 palaeoichnology'(Sarjeart in Casamiquelaet al. 1987, p. 5).I\ t.-i 186 M. ROMANO& M. A.'WHYIE fact they had probably been observedaround 1895,sinca it is accounts.Certainly dinosaurshad not become significantly reported (Hargeaves 1913, p. 92) that a 'Mr. Rowntree less fashionable,nor Ìvas there any lack of active Ìvork on obtained a lootprinr frcm Cayton Bay [south oî Scaúorcugh], dinosaurtracks elsewhere in the Ìvorld,since this was the tirne which Mr Lamplugh prcnouncedto beprobably crocodílían'. (between1939-1954) that Roland T. Bird publisheda seriesof Despite their early recognitionin this area,thoùgh consider- popular articleson the subsequentlyîamous sauropod track- ably later than the first findsof Triassicprintselselvhere in the way at the PaluxyRiver site in Texas,USA (descriptionsand country (Sarjeant1974), there has not been a consistentflow referencesin Farlow & Lockley 1989;Farlow et al, 7989; of publicationson theseemotive yet enigmatictlace fossils. Lockley & Hunt 1995).So why did British workers not fully Paperspublished on Yorkshire dinosaurtracks over the last exploit the ch pickingsof dinosaurhacks on the eastcoast? 100 years show a strongly bimodal production rate (Fig. 1). Part of the reasonmay havebeen that trackswere regarded as Following an initial rush in the earlypart of the 20th century, rare and,indeed, when the presentauthors started work on the that coincidedlvith H. C. Beasley'sinvestigations in the Tri- Middle Jurassic dinosaur t acks of Yorkshire (Whyte & assicoî Cheshire(Sarjeant 1974), numbers of papersdeclined Romano 1981),there waslittle indication as to the wealth of until the znd World War and did not increaseasain until thc material that vr'ouldcome to light, However, it soon became mid-1970s. apparentto us that dinosaurtracks, far ftom being just scat- tered or relativelylocalized occurrences, actually characterize This dearth of pape$ between1920-1970 on the Yorkshire many of the non-marinerock sequencesof this area. They dinosaurtracks is recognizedin two comprehensiveaccounts occur throughout the Middle Jurassic,often in considerable by Sa{eant (1974)and Delair & Sarjeant(1985) on the history numbersand in a variety of facies.Thus the earlyrecords that of the stùdy of fossil vertebratefootp nts in the British Isles. gavethe impressionthat prints tendedto occu at particular In these\ryorks, Jurassic Yorkshire dinosaurp nts occupy a horizonsor beds,such as the'footprint bed'at Bùmiston combined total of just over four pagesof text and 13 refer- (Hargreaves1914) and the'Unio bed' at Whitby (KendalÌ ences,whereas the TriassicCheshire/lancashire prints merit 1908),are noìv known to be rather biasedviews and do not over 21 pagesof text and in excessof 100referelces (aÌthough, reflectthe true picture. admittedly,Beasley contdbuted 19 of the latter!). It is diff,cult to pinpoint why, following the initial recognitionand subse- Anolher reasonfor their unpopularity(though certainly not quent publications,the interest in theseYorkshire dinosaur peculiarto Yorkshire)may bave beenthat the full potential of tracks was not sustained,at least with regardsto published the trackswas not appreciated.Hence the early paperson the tracks of the east coasL(Brodrick 1907,1908, 1909a, 1909b; Kenda[ 1908; Hargreaves 1913, 1914; Fox-Strang\a,ays& Barrow 1915;Black et at. 1934)dealt mainly with print shape and assignmentto particulardinosaur groups. Yet, apart from possiblyenabling the maker to be identified (though in fact this is probablyrather rare),the tracksalso may provideinfor- mation on the sizeof the animal (hip height,gleno-acetabular 0) distance)and its behaviour(mode oflocomotion, gait,speed). Also tracksmay supplyevidence on abundance,diversity, and ecology (gregariousnature, migratory pathways,prefe[ed o habitat),as well asyielding information on the stateof the sub- strate during footprint fomation. Pioneering work by = _o Alexander (1976,1985) also showed that the speedof loco- l motion could be deducedfrom their trackways.