Tethyshadros (Tethys Bulk, referencing the Tethys Ocean where its island is situated in, and "hadrosaurs", which means "Bulky Lizards") is a genus of non-hadrosaurid hadrosauromorph dinosaur that lived in the portion of the Calcare di Aurisina Formation within Trieste, Italy, 81 - 80 million years ago, during the Campanian stage of the Late Cretaceous Period.
Originally believed to be a hadrosaur shrunken due to living on an island, a discovery made during the making of Prehistoric Planet Season 2 revealed that Tethyshadros was simply small due to being very primitive.[DN 1] In fact, it is too primitive to even be considered a proper hadrosaurid. Even so, Tethyshadros, along with its Maastrichtian relatives Telmatosaurus and Fylax thyrakolasus, is considered one of the latest non-hadrosaurid hadrosauromorphs. It was fairly small, around 4 - 4.6 meters (13 - 15 feet) long (as estimated from a tail around 2.5 meters, or 8 feet, 3 inches, in length)[1], weighing around 338 – 584 kilograms (745 - 1287 pounds).[2][3]
“ With its unique, serrated bill, it can forage among the tough vegetation. ”
Tethyshadros had a unique, serrated beak with a pointed protrusion, believed to serve as a means to shred the plants of its island home, like conifers and gymnosperms.
Prehistoric Planet's Portrayal[]
Prehistoric Planet depicts Tethyshadros with green skin and dark, stout stripes, with a lighter-colored underside to provide countershading to help the animal blend in with its surroundings better.
Paleoecology[]
Paleoenvironment[]
The Liburnia Formation of Trieste, Italy as depicted in Islands
“ The longer an island has been isolated, the more different its animal inhabitants may become. ”
Tethyshadros lived in Trieste, Italy, within what is known as the Calcare di Aurisina Formation (which also streches over to Slovenia). The place was once a tropical carbonate island full of conifers, a few gymnosperms, and several angiospermous pollen types, surrounded by large forests.[4][DN 2][3] While the show was being made, the dinosaur - and by, extension, the area - was believed to be 70 million years ago, dating back to the Maastrichtian age of the Late Cretaceous Period, with the chalkstone lens that contained the fossil once thought to be part of another formation known as the Liburnia Formation. However, in 2021, a study reevaluated the remains of the Tethyshadros fossil and discovered that it lived 81 - 80 million years ago, during the Campanian stage, though all of these discoveries were made too late for the show to adjust, thus, Tethyshadros was depicted living in the wrong time, hunted by the wrong predators. Its habitat on the show, though likely based on the Liburnia Formation rather than the Calcare di Aurisina Formation (as the correction was not yet known by that time), is less affected by these new discoveries, however, as the segment's exact location was never explicitly stated.[3][DN 3]
Paleofauna[]
Hatzegopteryxes fly down to the Liburnia Formation of Trieste, Italy
“ Hunters like T. rex have never reached this little island, so it should be a safe place for a mother to raise her brood... but not necessarily. ”
While this island isolates them from most predators, the area can still be visited by some hunters like giant azhdarchids that are capable of flying to any island within reach. Although Hatzegopteryx could not have actually hunted Tethyshadros (for the former lived 10 - 15 million years after the latter), scenarios similar to the scene portrayed in Prehistoric Planet could have still happened, since Tethyshadros did have Maastrichtian relatives like Fylax thyrakolasus (which lived in Spain around 66 million years ago),[DN 4] and remains of Hatzegopteryx, or, at least, azhdarchids of similar size, have been found all over Europe.[DN 5] At least one pterosaur metacarpal (palm bone) was found in the Calcare di Aurisina Formation, but not much can be assumed regarding it. Furthermore, the Calcare di Aurisina Formation does have traces of dromaeosaurs, troodontids, other coelurosaurs, and other indeterminate theropods that would have served as the island's native predators. The region also had hadrosauroids like Tethyshadros, iguanodontids or rhabdodontids, other ornithopods, crocodylomorphs, fish, bivalves, and other animals.
Social Behavior[]
Juvenile Tethyshadros fleeing to their mother during a Hatzegopteryx attack
Prehistoric Planet depicts Tethyshadros as living in herds with members of all ages, but, according to Dr. Darren Naish, Prehistoric Planet's lead consultant, it is still unclear whether the juveniles actually lived with the adults for long.[DN 6] Having likely experienced constant Hatzegopteryx attacks, the Tethyshadros keep an eye out on the sky, and immediately retreat once the azhdarchids are sighted. To avoid them, they retreat to the forests, seeking refuge behind the trees that are too tightly-packed for the massive hunters to fit through and continue pursuing them.
Parental Habits[]
Even so, some herd members, like juveniles, might not be able to retreat in time due to lesser experience, and thus remained stranded in the open. Their mother, while showing parental concern, has proven not to be all that intelligent, for she called out to her young while the Hatzegopteryxes are still there, notifying the predators that there is still prey out in the open (though they would have likely tried checking the fields for prey that is still present regardless). This ends up resulting in one of the juveniles being eaten, with the surviving youngsters rushing into the forest, nuzzling with their mother.
Filming Location Thetford Forest, Norfolk and Suffolk, England[PhP 1]
In the second segment of Islands, by the small islands of southern Europe, a herd of strange, elusive herbivores graze through a field of pine saplings. These creatures, known as Tethyshadros, are just a quarter of their mainland cousins, the adults standing no taller than a human being. For a moment, all is peaceful, with the herd foraging through the tough vegetation with their unique, serrated bills. But as the breeze blows, an air of unease takes hold of the island. One adult, sensing threats around, rears up and finds, to its horror, a flock of Hatzegopteryx coming down from the sky. The entire herd panics as the azhdarchids, numbering around four males and three females, land and gallop after them (with one of the hunters even grabbing a juvenile upon landing). Most of the herd's members rush to the safety of the forest, where the trees are too tightly-packed for their pursuers to come through, thwarting the pterosaurs and causing one male to bellow in frustration. Not all Tethyshadros have escaped to the safety of the woods, however, with three juveniles left hiding in the fields.
“ The youngsters' best hope is to stay completely still... and not to run. ”
From the forest, the mother of the juveniles calls out to her children. Due to this, the predators realized that there are still some hadrosaurs out there that they can still hunt, prompting them to try and scour the clearing to flush out prey that might still be there, with the fearful juvenile hadrosaurs trying to stay completely still. As one male Hatzegopteryx approaches their hiding spot, one baby Tethyshadros panics and tries to run for the forest, with the rest following suit now that their cover is blown. One juvenile is promptly snatched up by the male Hatzegopteryx, while two other juvenile Tethyshadros make it back to their mother during the commotion. A female Hatzegopteryx tries to grab the male's hard-earned catch, only for the male to turn away and swallow the juvenile as the female continues to pester him.
“ These two are lucky to be back with their mother... the island-hopping pterosaurs move on to try their luck elsewhere. The hadrosaurs can return to feeding. ”
After what appears to be a brief conversation via the clacking of beaks, the Hatzegopteryx males agree to leave for another island. One by one, they fly off to hunt elsewhere, with the last of the four males carrying yet another dead juvenile Tethyshadros in his beak. When all the azhdarchids have finally left, the Tethyshadros herd leave their forest sanctuary to continue grazing.
“ Some islands are so small, that they have no large land-living residents. But they may nonetheless get visitors. Hatzegopteryx. This male has arrived carrying a 40-pound Tethyshadros carcass, a prize from a recent hunt. ”
In the sixth and last segment of Islands, an older male Hatzegopteryx, sporting a brightly-colored crest of vibrant yellows and blues, lands on the island with an 18-kilogram (40-pound) juvenile Tethyshadros. However, he hasn't come here to enjoy this meal in peace. Instead, he surrounds his catch with wood picked up from the beach to form a ceremonial nest of sorts, spreading and flapping his massive wings over to entice passing females to mate with him.
“ He has constructed a display to make it clear to any females passing overhead that he is looking for a mate. But he might have a very long wait before he gets a response... at last, a female. She seems interested, but a little more persuasion might be necessary. And he needs to be careful. One well-aimed peck from her beak could quickly bring his mating season to an end. His display must demonstrate that he has the good genes that her young would do well to inherit. ”
When one arrives, he lifts up the dead Tethyshadros to prove that he is a great hunter, and that he is also strong for having flown a great distance to bring the body there. While impressive, simply proving his strength is not enough. To convince her some more, he displays his crest and courts the female with enticing grunts, clacks, and head movements, gestures that the female appears to reciprocate well. Following a synchronized dance where both of them repeatedly clack their beaks against each other softly and stare up at the sky, he seems to have established trust with the female.
“ Another male. He's much younger, but he could still be a rival. ”
Suddenly, a younger male Hatzegopteryx, sporting the usual color scheme, lands down, and slowly approaches the couple. Enraged, the older male bellows and charges at the new arrival, catching the younger male completely off-guard and forcing him to slowly retreat. The older male aggressively snaps at him repeatedly and ends up grabbing his right wing. Grunting in pain, the younger male decides to back out and flies off, the older male bellowing at him to ensure that he doesn't return. In the chaos, the female flew off due to the commotion, with the old male believing that his chance is gone. Fortunately, the female returned, having seen the older male's successful assault as more proof of his eligibility.
“ She's back. Seeing off a potential rival might even be another point in his favor. He continues from where he left off. One last reminder of his strength... and this is his only contribution to fatherhood. It's all over in just a few seconds... but it's the start of the next generation of these giant flying hunters. Islands like this may only be small, but like countless others around the world, they bear witness to crucial moments in the lives of some of the most unusual creatures on the Prehistoric Planet. ”
He nudges the dead Tethyshadros close to the female as one last reminder of his prowess, and they mate. After mating with the female in a relatively short span of time (with this being his only contribution to fatherhood), the female flies off as the male grooms himself and starts the courtship ritual again, ready to attract more females, the dead Tethyshadros left intact in the center of his symbolic nest, ready for the next show.
