DINOSAUR FOOTPRINTS FROM THE UPPER JURASSIC CASTELL N FORMATION "TACURU GROUP", TARIJA DEPARTMENT, BOLIVIA

LIMBER LOVERA CRUZ; RAUL ESPERANTE; PAOLO CITTON; CÉSPEDES-LLAVE ANGEL; MENDEZ TORREZ GUSTAVO; SEBASTIAN APESTEGUIA

Congreso; 3rd Palaeontological Virtual Congress Palaeontology in the virtual era; 2021

Bolivia has an outstanding vertebrate ichnological recordfrom uppermost Cretaceous deposits, and besides, recentlya Triassic locality was reported. To date, there has been norecord of Jurassic dinosaur tracks. We report a site from theEntre R os area (Autonomous Department of Tarija) withinthe Upper Jurassic Castell n Formation, with a surfacepreserving about 350 dinosaur tracks, that extends the recordof ichnological localities in Bolivia through the three periodsof the Mesozoic Era. With the exception of !ve tridactyl tracks,all remaining footprints exhibit sauropod characteristics.Three medium-gauge, quadrupedal trackways composed oflarge pes impressions appear sub-parallel with one orientedin the opposite direction of movement. The best preservedtrackway shows pes impressions of about 95 cm and 75 cmin mean length and width, respectively. The trackmaker wasabout 3.80 m tall at the hip and walked at a speed less than5 km/h. Morphology and purported geologic age points to anon-neosauropod eusauropod trackmaker, even if a memberof Titanosauriformes, like a somphospondyl producer, cannotbe discarded. Some dozens of small-sized sauropod tracks,less than 15 cm in pes length, appear associated with twotrackways. This inherent con!guration constitutes a case studyto test the main clues currently accepted to discriminate herdbehaviour among trackmakers. It likely suggests that otherclues must be considered to strengthen identi!cation ofsynchronism among track formations, that together with thetrackmaker identi!cation, is a conditio sine qua non vertebrateichnologists can con!dently speculate about gregariousness.