It's common knowledge : kids love dinosaurs. As a result, it was unavoidable that Toei would use dinosaurs in its major tokusatsu franchise, Super Sentai. Dinosaurs and prehistoric animals have appeared as early as Battle Fever J as Monsters of the week. With the appearance of animal mechas in Liveman, it was only a matter of time that a dinosaur themed Super Sentai would be made. And it would be in 1992, with Kyoryu Sentai Zyuranger the first dinosaur themed sentai series. Since then, two other dino-themed series have followed: in 2003, Bakuryuu sentai Abaranger, and in 2013, the current super sentai series, Zyuden Sentai Kyoryuger. Besides, dino-themed mechas have appeared in other series such as Timeranger, Go-onger, Shinkenger, Goseiger and Gokaiger.
I'm gonna focus now on the three main dinosaur sentai series: Zyuranger, Abaranger and Kyoryuger. It can be noticed that the exploration of the dinosaur motif went deeper with each series, with Zyuranger being the beginning, with a few well known animals, Abaranger going more in detail with more species, and Kyoryuger being able to go even further.
Zyuranger came at a time when the animal mechas were just beginning to appear in the sentai franchise, and, at that time, most of the mechas appearing were, first, the individual mechas for each hero, then, a second robot (Zyuranger introduced the first regular sixth ranger) and, at last, a big mecha towards episode 30. The animals in Zyuranger were prehistoric animals, but only about half of them were dinosaurs, and there were even two mammals among them. Each of the main 5 rangers was themed after an animal, and their mechas, weapon and even for three of them, their motorcycle was themed after them. The sixth ranger even had a non prehistoric animal, a dragon, as his theme. Zyuranger was the starting point of the dinosaur theme in the franchise, and at that time, all kind of prehistoric animals were included into the theme, even mammals. Another point: the tyrannosaurus had an upright stance, that was shown to be inaccurate.
Species in Zyuranger
Tyrannosaurus (Red Ranger's animal)
Triceratops (Blue Ranger's animal)
Other prehistoric reptiles
Pteranodon (Pink Ranger's animal)
Mammoth (Black Ranger's animal)
Saber-tooth Tiger (Yellow Ranger's animal)
Dragon (Sixth ranger (green)'s animal)
Abaranger aired eleven years after Zyuranger, in 2003. Between Zyuranger and Abaranger, a lot of series have developed the animal mecha concept, and the number of individual mechas has increased a lot, starting with Kakuranger. Moreover, CGI were used a lot more, and Gaoranger used CGI to great effects and had a huge ranger of animal mechas. As a result, Abaranger was able to show more diverse dinosaurs than its dino predecessor, the designs could be more precise and accurate with paleontological data. An example was the way the Tyrannosaurus stance was changed as a more horizontal, and, as such, more accurate. Abaranger used its dinosaur motif in the mechas and weapons of the heroes. While some of the mechas weren't true dinosaurs, they were all prehistoric reptiles, and, unlike Zyuranger, most of them were true dinosaurs. As much as 16 prehistoric reptimes were mentioned, and while most fo them are "stock dinosaurs" (meaning dinosaurs often mentioned in popular culture)
Let's review Abaranger's animals: I'll show in bold the dinosaurs (and other animals) which had a mecha themed after them; in the other cases, I'll mention how the dinosaur was shown
Brachiosaurus (Black ranger's mecha partner and main weapon)
Tyrannosaurus (Red Ranger's mecha partner and main weapon)
Carnotaurus (movie mecha)
Spinosaurus ( theme of the helmet of the third main robot)
Velociraptor (or Deinonychus) (Road Raptors, a horse-like way of transportation for the four main rangers (Red, Blue, Yellow and Black)
Triceratops (Blue Ranger's mecha partner and main weapon)
Chasmosaurus (Movie mecha)
Styracosaurus (mecha and Red's special weapon)
Pteranodon (Yellow Ranger's mecha partner and main weapon)
Tupuxuara (Additional(White) Ranger's mecha partner and main weapon)
Rhamphorhynchus ( theme of the weapons of the third main robot)
A few fun details: the Abaranger's enemies had some prehistoric animals as themes, with the ammonite being a theme of the evil armor, and Anomalocaris as enemy ships. Last, a supporting character had a crocodile theme, crocodiles being distantly related to dinosaurs (crocodiles are archosaurs)
Ten years after Abaranger, a new dinosaur themed sentai series is airing this year: Zyuden Sentai Kyoryuger. At the time Abaranger was made, Super Sentai had already tried the maximum number of mechas it could use in sentai, and as such, Kyoryuger couldn't go much further than Abaranger in the diversity of dinosaurs as the heroes's mechas. It can be noticed that the mechas and gattai in Kyoryuger are pretty similar to those seen in Abaranger, and, with a few exceptions, pretty use the same species. However, Kyoryuger has found a way to explore more the dinosaur theme by using the concept of the Zyudenchi (the Beast Battery), that would be used with the heroes's weapons and would be able to make special attacks. While the number of mechas in Kyoryuger would be pretty similar to Aba's (10 mechas in regular series (vs 11 in Aba); 1 special movie mecha (vs 2 in Aba)), three additional dinos would be used to make weapons or vehicles, and ten other animals would be used as batteries for the special attacks. Like Abaranger, most of the animals used in Kyoryuger are dinosaurs; however, some mechas and batteries use non dinosaur reptiles, and even the ammonite was used in a battery. While the dinosaurs and other reptiles used for the mechas are pretty "stock dinosaurs", some of the dinosaurs used as batteries are less known.
Kyoryuger also went a little further than Abaranger by highlighting the relationship between dinosaurs and birds, and introducing the concept of feathers in dinos
I'll show in bold the dinosaurs used as mechas, and mention their partner when he (or she) is a main character; when the animal is used in another way than merely a special attack or being a part of Bragigigas's mecha, it will be mentioned.
Tyrannosaurus (Red Ranger's mecha partner and main weapon)
Spinosaurus (movie mecha)
Velociraptor (Green Ranger's mecha partner and main weapon)
Deinonychus (mechas used as bikes by the main heroes)
Stegosaurus (Blue Ranger's mecha partner and main weapon)
Kentrosaurus (Battery used to make the weapon made from the five individual weapon of each main ranger, the Kentrospiker, used in final attacks)
Parasaurolophus (Black ranger's mecha partner and main weapon)
Triceratops (Pink Ranger's mecha partner and main weapon)
Pteranodon (Additional (Gold) Ranger's mecha partner and main weapon)
Tupandactylus ( theme of the weapons of the third main robot)
Deinosuchus (special weapon)
Ammonite (shelled cephalopod)
Fun detail: Torin, the heroes's mentor, has a bird or feathered dinosaur theme ; as such, he's pretty much the way Kyoryuger links dinosaurs and birds
Note: Theropods were classified not according to their phylogenic group, but rather by their size; I did it, because Tyrannosaurus is more closely related to Velociraptor and Deinonychus than to other similar looking dinosaurs like Allosaurus and Carnotaurus, and I wanted to avoid putting the big carnivorous dinosaurs apart.
For the curious ones, here is the phylogenic classification of theropods in each show
Velociraptor (or Deinonychus)