I left off discussing how in the current online Tarzan adventure, Tarzan does encounter any other other large dinosaur species other than than the gryf. The Manning strips, which I grew up with, had a much great diversity of dinosaurs and giant mammals.
I believe this is to keep the strip as true to the original as possible, and I doubt there will be any additional dinosaur species (save perhaps if they venture into the swamp region?)
I left off saying that ERB suggested there was a great profusion of unique wildlife in Pal-ul-don, some of the species ancestral forms of African wildlife, others unique strains evolved in islolation. The ja, or spotted lions might have been either. The authors introduce one other such species, a erthystic or red hyena. There might have been beast's like calicotheres and ancient giraffids among others. Who knows? There is actually a profusion of "living fossils" and unique evolved wildlife here. Pal-ul-don would be a paleontologist's dream come true were it real.
However, what appears lacking as creatures as huge and dramatic as the gryf. The other wildlife would be of interest mainly to experts.
The ja, jato, and gryf appear to be the only dangerous creatures inhabiting the land. That seems to rule out the other huge, meat-eating beasts that make travel in Caspak or Pellucidar a moment to moment hazard. Where are the huge flying reptiles that are a constant menace in those other lost lands? They don't appear to be native to Pal-ul-don, in spite of the Manning strips, and even the recent novel. Pterosaurs are flying creatures, by the way, and could easily fly over the barrier swamp (perhaps a layer of thick mist might keep winged reptiles from spreading throughout the rest of Africa?).
There was one other dinosaur and/or prehistoric reptile species in the canonical tale, the unidentified swamp saurian, which I've speculated elsewhere sounds very like s suchamimus or baryonyx. And what might have titantic reptilian monsters glimpsed by Tarzan in the swamp (gryfs, swamp saurians, or something else?). Other creatures like possibly a dwarf brontosaurus, as I've read speculated, could also live on there.
The gryf, however, seems to be the only surviving dinosaur extant on the Pal-ul-don mainland. It is Pal-ul-don's most formidable creature, seeming to rule out similarly spectacular beasts, such as brontosaurus, stegosaurus, and T-rex.
This a relatively small, isolated valley. In this case, Burroughs offers an example of what a real-life lost world might really be like. It is simply not big enough to hold the profusion of giant fauna found in typical lost realms, such as A C Doyle's Maple White Land, or ERB's own Caspak. Even a large island, could not possibly contain Caspak's teeming, Pellucidar like richness. And the primeval fauna that does survive has been altered over the millinea.
Manning's Pal-ul-don strips, of course, certainly do contain Pellucidar-like richness. Even the the stories (which I intend to actually chronicle here when I get the time!) seem more like Pellucidar tales, in that they involve a series of perils and escapes, while Manning's Pellucidar strips seem to be more about political intrigue, which is a bit more similar to Tarzan the Terrible.
Then there are the old Dell comic Tarzans, that took Tarzan back to Pal-ul-don thoughout its long run. This seems a far different take on the lost land, and there are many Pellucidaran elements, including the names "thipdar" and "dyal". Just looking at the Dell version, and taking it as a separate timeline, it is posible that THIS version of Pal-ul-don actually connects with Pellucidar, and perhaps the humanoid inhabitants are Pellucidaran colonists. It is, then a portion of Pellucidaran existing on the surface. After all, they appear to lack tails, even though the Ho-don and A-lur are often shown. This might explain the Pellucidaran terms, and perhaps the similarity of the words "gryf" and "gyor" and "garth" and"zarith."
But back to the canonical ERB "universe."
There is one passage in the novel that suggests cave-painting, depicting what appear to giant saurian-like creatures (correct me if I've wrong about this!).
Perhaps, then, in the distant past, other giant Mesozoic survivors did inhabit the land. I've speculated in "Evolution in Pal-ul-don", that the lost land as depicted by Manning, which is supposed to exist in a sort of time bubble, and might be continent size, perhaps connecting Africa with South America sometime after the Cretaceous, after most of the dinosaurs died.
Perhaps, giant dinosaurs and mammals slowly met final extinction as the land shrank, until only the gryf remained, taking its place as the valley's top predator and herbivore. Becoming omnivorous would most certainly be an advantage, since it was less specialize and able to survive on a wide diet of food.
If large theropods such as the garth existed, they were less adaptable and died out. The Burroughs
Bestiary by David day, however, suggest something more bizarre, however: that the herbivorous ancestors of the gryf might have mated with tyrannosaurs to produce the carnivorous nightmares encountered by Tarzan! It is not feasible, of course, that a ceratopsian could be genetically compatible with a theropod. But, again, this is ERB's universe where stegosaurs can utilize their plates to glide, so who knows? We already know that the jato survived in the same manner by mixing with lions!
There is one other thing that Manning seems to have forgotten in his own stories, which doe not necessarily rule out other giant beasts in Pal-ul-don, but does suggest it. In both the Manning strips and ERB's novel, the Ho-don revere the gryf as almost a creature of supernatural, as it features prominantly in their relgious art. If other similarly spectacular monsters abound, then this seems far less feasible. Perhaps the Ho-don retain ancestral memories of such beasts, but that is long forgotten. If the gryf is the sole surviving mesozoic monster, than the of the Ho-don awe is more feasible, as is the role of the gryf in Ho-don culture.
Then there is the fact that the Ho-don also use the gryfs as war-beasts, while in the novel, they seem astonished that Tarzan is able to ride on one's back! Somehow, they never learned from the Tor-o-don. Perhaps the Ho-don learned to domesticate the gryf following Tarzan's example, but Manning never explains this.
The author of Tarzan's Return to Pal-ul-don suggests that a future sequel might also lead Tarzan to other corners of the lost land, where more giant survivors might lurk. But that will need to wait.
Now on a personal basis, out of the three discussed versions of the lost land, does anyone have a "favorite"?
For me, I'd have to say Manning's, hands down.
The Dell version's relatively poor artwork, and the fact that they borrow from the rest of Tarzan's Africa plus Pellucidar rule it out. Plus, no tails. The tailed inhabitants are what makes Pal-ul-don unique among lost lands. It's just not Pal-ul-don without the monkey men.
And the canonical version, as innovative and realistic as it is, the answer is obvious. You just don't get the diversity of large prehistoric fauna.
Manning gives us the best of both worlds.