In this month-long "Retrosaur Challenge" from TyrantisTerror, we will revert back to the olden days of Mesozoic reptile restorations - featuring tail-dragging carnosaurs, featherless raptors, swamp-dwelling sauropods, naked flying pterosaurs, kaiju-like mosasaurs, and many more!

Day 5: Duck-Billed Goliath

    Telmatites ("marsh dweller") was a genus of telmatitid Duck-Billed Goliath that inhabited what is now western North America during the Late Cretaceous, existing between 86 and 68 million years ago. Telmatites was a moderately-sized member of its clade in life, with adult individuals averaging out at around 33 feet (10 meters) in length, 15 feet (4.6 meters) in height, and 5 tons (4.53 tonnes) in mass. It was also one of the most common megafaunal retrosaurs in its environment, as evidenced by the sheer number of fossil specimens pertaining to the genus uncovered from various Late Cretaceous-aged formations and its division into at least four distinct species throughout its existence. A few specimens have even been discovered with well-preserved soft tissues, including those that preserve interdigital webbing and a fleshy dorsal ridge - apparent adaptations toward a semiaquatic lifestyle. Telmatites’ prosperity is likely owed to its more aquatic habits than other Duck-Billed Goliaths and generalistic diet of subaqueous plants, which enabled it to avoid competition with many of its relatives, but its success was not limited to its native range. Two closely-related taxa once considered species of Telmatites, Cassidalator and Shamolophus, have been found in similarly-aged Asian deposits - indicating that these strange Duck-Billed Goliaths were widespread across Laurasia in the Late Cretaceous. 

    Remains of the four valid Telmatites species have been unearthed from many North American locales, ranging from the early Santonian to the mid-Maastrichtian in age. T. selwyni is the oldest species, known from the Santonian-aged Steer Springs Formation in southeast Wyoming - where it coexisted with the carnosaurid Gigantotherus, the Tiny Tyrant Nanotherus, and the agathaumid Clypeocephalus. T. sternbergorum is the second-oldest species, known from the early Campanian-aged Niobrara Chalk in Nebraska, whose rich marine deposits have also yielded several notable Flying Tyrant and Leviathan taxa. T. anatoceps is the type and most well-known species, known from a few Campanian-aged formations ranging from as far north as Montana to as far south as New Mexico, where it lived alongside a whole host of other retrosaur genera - including the dynamosaurid Tyrannogorgon, the Club-Tailed Goliath Apatochelone, the Tiny Tyrant Dryptonychus, and a handful of other Duck-Billed Goliaths. T. edmontonicus is the largest and youngest of the four species, known from Maastrichtian-aged deposits in Montana and Alberta, where it shared its environment with the likes of the notorious True Tyrant Dynamosaurus and the equally-famous Horned Goliath Agathaumas. If the geologic compositions of these formations are anything to go by, it can be assumed that each species inhabited a different type of habitat as well. The sandstone and mudstone makeup of the Steer Springs indicates that T. selwyni preferred swampy or estuarine areas, while the marine chalk and shale that the Niobrara Chalk is composed of suggests that T. sternbergorum resided in and around coastal areas on islands in the Western Interior Seaway. Both T. anatoceps and T. edmontonicus are known from formations whose makeup primarily consists of claystone and mudstone, evincing that these two species occupied riparian and lacustrine habitats further inland. 

    As mentioned before, Telmatites were among the most common megafaunal retrosaurs in their time and environment, residing in small herds within the swampy, riparian, and lacustrine areas that this herbivorous reptile preferred to inhabit. These Duck-Billed Goliaths would have been superb swimmers thanks to their laterally-compressed tails and webbed digits, diving many meters beneath the surface of their watery abodes to feast upon aquatic plants throughout much of the day, intermittently resurfacing to breathe fresh air. As their comparatively-large eye sockets seem to suggest, terrestrial foraging by night was also a possible feeding behavior for these retrosaurs, perhaps being a means to avoid competition with their diurnal relatives and predation from many Paleo Tyrants. Contrary to popular belief, adult Telmatites were more than capable of fighting back against marauding True Tyrants or packs of Tiny Tyrants if they were unable to reach the safety of deep water in time. The sharp claws on their hands could easily lacerate or even puncture enemy hide, while their laterally-compressed tail would have doubled as an effective bludgeoning weapon to topple equally-sized attackers and cripple smaller assailants with well-placed swings. The crest adorning Telmatites’ skull was composed entirely of solid bone, a feature that would have made it useful for shoving matches between rivals of the same species and for battering predators. But even this biological arsenal, along with their semiaquatic lifestyle, could not guarantee these retrosaurs an adequate defense against every threat toward their survival. For instance, a T. anatoceps specimen nicknamed “Broken Betty” was discovered in a rather mangled and dissociated state, with numerous bite marks and shed teeth belonging to a Phobosuchus found amongst its scattered bones - suggesting that it met a rather gruesome fate at the jaws of the enormous crocodilian. In a similar case, several areas of one T. sternbergorum skeleton have preserved bite marks that were inflicted by sharks that had either attacked it while it was swimming out at sea or had scavenged its corpse after it had perished.  

    The most well-known clade of Bipedal Goliaths, the Duck-Billed Goliaths were given such a catch-all term because many of these herbivorous retrosaurs bore skulls and beaks that looked superficially similar to those of modern waterfowl - with the batteries of grinding teeth lining their jaws distinguishing them from their smaller feathered copyists. They were also among the most successful retrosaur clades on the herbivorous side of the family tree, quickly spreading across Laurasia in the late Early Cretaceous following the decline of their ancestral clade, the Iguana-Toothed Goliaths. Though these retrosaurs were generally similar in overall shape, a fair amount of diversity existed within the group. Several species possessed head crests that contained elaborate nasal passages in life, enabling them to produce strange vocalizations for intraspecific communication. The armacristasaurids, on the other hand, developed cranial ornamentation designed for combat against rivals and predators alike - from Securemacrista’s axe-shaped crest to the impressive antler-esque structure seen in male Cuchulhainasaura. Oriental Asia was home to the bizarre dolichohadrids in the Mid-Cretaceous, which seemed to have occupied niches akin to Long-Necked Goliaths elsewhere while the region was isolated from the rest of the world. A few taxa even took the semiaquatic lifestyle of their relatives a step further; Anatohydrum was eerily similar to a hippopotamus with its body plan and aquatic adaptations, while the related mirandanatines almost resembled the birds that gave the clade their nickname in the first place. What greater evolutionary potentials these herbivores could have achieved were sadly rendered unobtainable by the events that terminated the Mesozoic era and the reign of the retrosaurs as a whole. Duck-Billed Goliaths remain one of the most well-studied retrosaur clades to this very day regardless, with insight into certain species’ paleobiology becoming a popular subject of scrutiny amongst paleontologists in recent times...   

Species:

- Telmatites anatoceps ("duck-faced marsh dweller")

- Telmatites edmontonicus (“marsh dweller from Edmonton”)

- Telmatites selwyni (“Alfred Richard Selwyn’s marsh dweller”)

- Telmatites sternbergorum (“marsh dweller of the Sternberg family”)

My main inspiration for this herbivore was, of course, the popular 20th-century paleoart trope of hadrosaurs as swamp-dwelling semiaquatic animals - albiet taking that now-disproven notion a few steps further here. Lambeosaurine hadrosaurs such as Corythosaurus and Hypacrosaurus inspired the general design of the head and crest, while the retrosaur’s fleshy dorsal ridge was modeled off the Lvl 31-40 Diplocaulus from Jurassic World: The Game. Many thanks again to my good friend OviraptorFan for creating a canonified redesign of my original Telmatosetes, which I used as a reference for this updated version!