A Late Jurassic diverse ichnocenosis from the siliciclastic Iouaridène Formation (Central High Atlas, Morocco)

The Late Ju ras sic IouaridÀne tracksite has been stud ied for de cades and is well-known for the ref er ence trackway of Breviparopus taghbaloutensis. These siliciclastic flood-plain de pos its bear prob a bly more than 1500 tracks, and at least 21 tram pled lev els: they yield tracks of me dium to very large sauro pods, pos si ble stego saurs and theropods. The first ac cu rate de scrip tion of the foot print as so ci a tion made by bi ped trackmakers is pro posed herein. More than six hun dred foot prints and more than a hun dred trackways has been mapped and ana lysed; this led to the def i ni tion of four tridactyl and two tetradactyl morphotypes, mainly pro duced by small to very large theropods, while prob a ble small ornithopod tracks are also pres ent. The bipedal foot print as so ci a tion is dom i nated by me dium-large theropods, which are also the most abun dant type. The tax o nom i cal at tri bu tion of the morphotypes is made dif fi cult by the poor pres er va - tion of many spec i mens. Fur ther more, for the most abun dant theropod tracks, those with “megalosaurian” af fin ity, there is also a com - plex ichnotaxonomical sit u a tion, that makes the at tri bu tions yet more chal leng ing; how ever, it was pos si ble to rec og nize the great af fin ity of the tridactyl spec i mens with the Megalosauripus tracks from the Ibe rian Pen in sula and North Amer ica. Three-di men sional mod els were gen er ated from the moulds of the best-pre served spec i mens to ren der a more de tailed de scrip tion and for eas ier ac cess to the spec i mens.