Titanosaur

The titanosaur is an unidentified genus of titanosaurian sauropod that lived in China during the Early Cretaceous period.

Portrayal in the series
To be added...

Dinobirds
The titanosaurs are first seen walking to the forest making a lot of noise. Nigel explains that large dinosaurs like these aren't usually found in dense forest. This is then followed by the Microraptors feeding off insects uncovered by bioturbation from the titanosaurs.

Later on, Nigel discovers a nesting site and realizes that the titanosaurs came so far into the forest to lay their eggs. Shortly after Nigel captures four Microraptors, the volcano erupts and one of the titanosaurs panic and stampedes towards a netted Microraptor. Nigel saves it but the titanosaur clipped its wing.

Nigel then sees the herd of titanosaurs going down to the erupting volcano and heads down to save them. He manages to get them through the time portal just before they died of suffocation.

When entering the 21st century, they cause damage to the fences surrounding the time portal, frustrating Bob. The episode then ends with the titanosaurs in their enclosure (for the time being).

Saving the Sabretooth
The titanosaurs are first seen breaking out of their enclosure and shortly after Nigel exclaims when he sees one eating from the trees.

They are last seen at the end of the episode with one eating away at Nigel's Base.

The Bug House
The titanosaurs are first seen when one walks down the path to Bob who is building the Bughouse. Bob says that they can't settle at the other side of the park. He tries to feed it cycad leaves but the titanosaur retaliates by breaking a wall that is being built. It then leaves breaking a wooden plank.

Later on, Bob realizes that the titanosaurs ate stones to grind up plant matter and he feeds the titanosaurs gastroliths to see if it works.

They are last seen when a titanosaur pulls Nigel's jeep out of the mud in the Carboniferous and through the time portal to the 21st century. Bob gives it a wheelbarrow of stones as a reward.

Supercroc
After Nigel rescues a Deinosuchus, Bob drives his jeep along with extra scraps from Nigel's mission that he will clean up. However, a Troodon has secretly snuck into the jeep searching for meat, and it attacks Bob, resulting in him losing control of the vehicle, which proceeds to startle the Titanosaurs. They then rampage through the park breaking enclosures and releasing various animals including the Elasmotherium, Ornithomimus, Terror bird, and Tyrannosaurus. This initiates the event known by many fans as the "mass break out."

Genus identity
Aside from being continually identified as titanosaurian sauropods, the exact genus of the dinosaurs was never revealed in the series. Fan speculation has put forth several identifications for the titanosaurs, namely Borealosaurus, Daxiatitan, Dongbeititan, and Ruyangosaurus. Although Borealosaurus was scientifically described two years before Prehistoric Park premiered, Dongbeititan lived at the right time period and its fossils have been found in Liaoning Province, where Episode 3 was set, but was, coincidentally, scientifically described one year after the series released.

Trivia

 * A titanosaur appears on the Prehistoric Park logo, taking a bite out of the "I" in "Prehistoric Park".
 * Nigel said that there were nine titanosaurs rescued, but only five are ever seen in the park.