Like his masters, the Ancients, Jonathan's name is parody of a part of the Mesozoic Era. His Japanese name, Jurasson, is a parody of the word "Jurassic", the middle age of the Mesozoic Era when dinosaurs grew in diverse numbers.
Throughout Series 1, Jonathan is damaged as not functioning properly, so his personality is quite "on the fritz". He has been seen to be clueless, kind, and prideful, among others. After being repaired, however, he is shown to be fiercely loyal and protective towards Rex and the Ancients, his builders. He serves them unquestioningly, even if he would wish to do otherwise, obeying Dr. Ancient over Rex to separate from the Space Pirates' ship in episode 78, leaving the D-Team's parents behind to keep Spectre from getting the Cosmos Stones.
As shown in the 4-part Series 1 finale, Jonathan possesses superhuman strength and agility, easily being capable of beating Spiny in a fight and hold off as many Super Alpha Droids as Chomp. He also possesses extreme resistance, being capable of taking a direct hits from Fire Scorcher and Volcano Burst and continue functioning for a few seconds.
Jonathan is an android created by Rex Owen's parents, who made him so that he could care for baby Rex. However, he is separated from Rex in the Time Vortex after Dr. Z ejected Rex and his parents from the Backlander.
Later, his head is turned upside down, causing him to lose his memory and take on various odd jobs. He is first seen as an airplane pilot in episode 6, flying Ursula, Zander and Ed over to the Swiss Alps. He later gave the D-Team a book of Dinosaur Cards in episode 10, but the Alpha Gang stole it. He later appeared in episode 18, disguised as a tour guide on Bali and later stating he came there to be a dancer.
He appeared briefly in episode 24, painting Chomp and Anchiceratops. He gave the D-Team an invitation to the Ninja Race in episode 34. He also pretended to be "Johnny Cook" and challenged Helga to a cooking match in episode 39.
In episode 42, Seth found him working on a train as a conductor in Moscow, Russia and went after him to retrieve some data from his memory banks using Tank. He succeeded and left him defenseless. Jonathan then protected Max, Rex, and Zoe from Terry's Volcano Burst which was deflected towards them by Ampelosaurus, becoming damaged and first being realized as a robot, and they brought him to the D-Lab.
In episode 46, Reese repaired him and Chomp spun his head back to its original state, and he started to regain his memory. After seeing Rod and Laura at Dr. Drake's, he was able to recall Seth stealing the data from him, and he stole their jet and went off to the Alpha Gang's Zeta Point to get it back. He even defeated Spiny, but was forced to retreat when Seth summoned Saurophaganax, and he saved Rex from the dinosaur. He then regained more of his memory and told the D-Team what happened in the time warp in episode 47. Seth's Black Tyrannosaurus then appeared.
He later helped the D-Team and Alpha Gang to defeat Seth by distracting the Alpha Droids, rebuilding Helga to bust them out of prison and watching out for Max Taylor in the final episodes 48 and 49. Max then gave him the Secret Dinosaurs and he delivered them to Rex before he was damaged from protecting him from Fire Scorcher. However, Dr. Ancient and Dr. Cretacia repaired him. He flew the Backlander off at the end of Series 1.
Immediately after, he was forced to return to the present by the Space Pirates' attack. He tried to fix the timeship, and began piloting it to take the D-Team through different time periods (Cretaceous Period, Ancient Rome, pirate-age Caribbean, Ancient China, Ancient Japan, Ancient Persia, Reniassance-era France, Jurassic Period, present-day, Stone Age, 3 years before the present, present-day again) while following the Pterosaur to find the Cosmos Stones, but sometimes for other reasons, like crash-landings and quick escapes.
At the end of episode 78, a Gel Jark knocked him out with Seth's lightning rod, and the Backlander crashed. When he was repaired, he piloted the Backlander against the Dark Pterosaur in episode 79 until they docked with the Space Pirates' ship, at which point Seth stole the Backlander to destroy the Dark Pterosaur once and for all. He piloted the Space Pirates' ship on the last time jump it could make to take the Ancients, Alpha Gang, Seth, and all the dinosaurs back to the future at the end of episode 79 as the series ended.
- Jonathan is one of the few major characters not to appear in the TCG (another is Reese Drake).
|p · e · t||Secondary Characters|
|Season 1 Allies:||Aki Taylor · Dr. Owen · Dr. Drake · Mrs. Drake · Newswoman · Monaco Fisherman · Dewey · Michelle · Amy · Mr. Stanley · John · Mary · Patrick · Temple Priest · Captain Mackerel · Meena · Stanley Spinoberg · Shino · Jonathan · Dr. Ancient · Dr. Cretacia|
|Season 1 Enemies:||Doppelgänger Alpha Gang · Ungaro|
|Season 2 Allies:||Sophia · Spartacus · Jim · Sanzo Hoshi · Shogun Tokugawa · Hanzo · Zahrah · Aladdin · Sultan · D'Artangnan · Athos · Porthos · Aramis · Princess Anne · Lady Constance · King Louis · Duke Dumas|
|Season 2 Enemies:||Sulla · Blackbeard · Copper · Kunoichi · Takeda · Zayid · Jon-Jon · Rasheed · Chancellor Richelieu · Royal Mother|