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Description

This is taken from the 2000 book Walking with Dinosaurs the Evidence, written by Darren Naish and David Martill, a tie-in to 1999’s Walking with Dinosaurs, which explains some of the thought processes behind the (now very dated) portrayals of the animals included in that series. I’ve posted this for the sake of offering some easily accessible information regarding some of the most controversial creative choices taken in the series.

So the “one-ton crocodile” from “Death of a Dynasty” has caused quite a bit of confusion among fans and unsurprisingly so, given the frankly shoddy way it was handled. If you need a memory jog, the episode features an animatronic crocodile head floating about and eyeing the duckbills and “Quetzalcoatlus” menacingly but since they didn’t have the budget to animate a crocodile attack, that’s as much screentime as it gets. But what is that crocodile supposed to be? The crocodiles known from Hell Creek tend to be on the dinky side, like Borealosuchus and Brachychampsa, with the largest one, the basal gavialoid Thoracosaurus reaching about 15 feet (possibly 20-25 feet based on some material) but it was no killer of dinosaurs. Fun fact, both Borealosuchus, and Thoracosaurus made it past the K-Pg extinction, the former even surviving into the Early Eocene, where it reached 15 feet long (B. wilsoni).

So is the crocodile meant to be Thoracosaurus? It does have a somewhat narrow rostrum but it’s not exactly comparable to that of a gharial, and according to the 2000 book, this is actually meant to be the gigantic, infamous killer of dinosaurs; Deinosuchus, the “terrible crocodile” of Laramida, or more accurately alligator, as it’s a basal member of the alligatoroid lineage, which includes today’s Alligator and caimans. What now? Yeah, I was just as confused as you were about this claim but after looking into it some more, I can speculate about the reasons behind the discrepancies. In a nutshell, I think both Crawly Creatures, as well as whoever was writing Kenneth Branagh’s narration screwed up big time. In the latter case, a weight of one ton is something the biggest extant members of Crocodylus can attain, specifically the saltwater and Nile crocodile, if they reach their max length of 20 feet, and obviously, a giant like Deinosuchus would have weighed a lot more, especially if you consider that the longer a croc gets its body mass increases exponentially. At 40 feet, Deinosuchus would have weighed as much as a T. rex (circa 8 tons).

And yes, it’s also odd that Deinosuchus never gets namedropped, especially since Branagh handled more complex names such as Eustreptospondylus. In other such cases in the WW series, this was done to handwave anachronisms/geographical displacements (albeit not consistently, like with Anurognathus), or so they could use cooler terms (like brontothere and gorgonopsid, instead of Embolotherium and Inostrancevia), and while you could argue that this was a case of the former, I have my doubts (more on it later). As for the animatronic head, it seems to have been based on the reconstructed skull for Deinosuchus hatcheri, which has a more bulbous snout tip compared to Deinosuchus riograndensis, but they made the rostrum far too narrow and ended up with a head that looks more like that of Sarcosuchus, while the real-life Deinosuchus had a very broad and robust skull and jaws that allowed it to crush turtles and drag dinosaurs to a watery grave. The novelization for WWD also refers to it as Deinosuchus and gives it an expanded role, while also touting the (very dated) 50-foot max estimates. By contrast, the 2000 book (as you can see) gives it a rather conservative and more reasonable max size of 33 feet (it also gives Quetzalcoatlus a more conservative wingspan of 38 feet), which was pleasantly surprising XD Okay, so we can confidently say that the “Death of a Dynasty” croc was indeed meant to be Deinosuchus but done dirty, but what about anachronism?

As you can see, the book addresses that, saying how the giant croc is only known from older rocks in Montana, which more specifically, is alluding to the Judith River Formation, which preserved some fairly large postcranial remains of Deinosuchus, stemming from individuals in the 35-40 foot range. While we haven’t found anything close to a complete skeleton, remains of Deinosuchus, usually in the form of skulls and jaws (often incomplete), isolated teeth, and isolated postcranial fossils, have been found all across North America, with many hailing from the eastern United States, but we have also found plenty of specimens in the west, mainly in the Texan Aguja Formation, which contains some of the largest specimens to date, comparable to the Judith River remains. The oldest occurrence of Deinosuchus is at the lower Blufftown Formation, dating to the early Campanian (83-80 my), while the youngest fossils date to the late Campanian (74-73 mya), such as fossils from the upper layers of the Black Creek, Demopolis Chalk and (once more) Blufftown Formations, while the Laramidian specimens tend to cluster in the 79-75 mya range, showing us that the genus (or at least a bunch of related large-sized estuarine basal alligatoroids) lasted for some 10 million years. This reflects how ectothermic, more generalized crocodylomorphs have a better chance at longevity than endothermic, more specialized and active dinosaurs and pterosaurs, but Deinosuchus itself eventually faced a massive hurdle. Given that these animals are usually found in estuaries and brackish water environments, it can be presumed that the disappearance of the great inland sea, which happened right before T. rex and its contemporaries arrived on the scene, was the reason behind the great croc’s extinction.

Given WWD’s lax attitude towards anachronism, and the fact that back in 1999, wastebasket taxonomy led to many Late Cretaceous archosaurs in North America having fossil ranges spanning from the Campanian to the late Maastrichtian, like Campanian azhdarchid fossils from Two Medicine and Dinosaur Park (the latter now identified as Cryodrakon) being attributed to Quetzalcoatlus, or in the case of fragmentary fossils of deinonychosaurians from Hell Creek (largely isolated teeth) being attributed to the Campanian Saurornitholestes, Dromaeosaurus, and Troodon (now Acheroraptor and Pectinodon), and others like Edmontonia (the Hell Creek species is now referred to as Denversaurus) and Chirostenotes also being treated as overly inclusive wastebasket taxa (with the fossils of Anzu, first discovered in 1998, initially attributed to Chirostenotes), you can see how the WWD crew could have felt justified in putting Deinosuchus as a contemporary of T. rex, since the more sharply defined line between Campanian and Maastrichtian archosaurs in Laramidia today was much blurrier and more ill-defined back in 1999. For context, most genera that did cross the boundary tend to cluster around the late Campanian-early Maastrichtian, while others, like Edmontosaurus, only showed up at the tail-end of the Campanian, 73 mya.

Though there is an interesting tidbit that might have served as additional inspiration (though this is speculative on my part), as some large but fragmentary crocodile fossils (large teeth and vertebrae) from Maastrichtian rocks in New Jersey and Delaware were tentatively attributed to Deinosuchus by some, leading to speculation about the genus having survived into the Maastrichtian. However, modern workers, including David Schwimmer (a foremost authority of Deinosuchus) are skeptical of that, suggesting that they may instead belong to Thoracosaurus (contributing to those controversial upper estimates mentioned earlier) or some other, indeterminate crocodilian. Giant crocodylomorphs pop up rather sporadically in the fossil record of the Mesozoic, and perhaps it’s not impossible that some other giant crocodilian (perhaps even a descendent of Deinosuchus itself that managed to adapt to the Maastrichtian’s challenge) inhabited Maastrichtian North America, but the absence of even a single tooth from Hell Creek (when we have such an extensive record of smaller crocs and various other riparian animals from this flood plain environment) suggests that they weren’t present in the general Hell Creek region specifically.

And as an aside, the entry also brings up how the giant alligator might have preyed on tyrannosaurs, citing a specimen of Albertosaurus that bears tooth marks attributed to a Deinosuchus. This is referencing a tyrannosaur specimen from Demopolis Chalk discovered in 1982, which was tentatively attributed to Albertosaurus by some workers, since it shared some anatomical features of albertosaurines (Albertosaurus and Gorgosaurus), but also since Albertosaurus was something of a wastebasket taxon for Late Cretaceous tyrannosaurs in the past (being the first one to be named, along with Tyrannosaurus, back in 1905). But in 2005, it was properly described as a distinct taxon, Appalachiosaurus montgomeriensis (an immature specimen at that), and later phylogenetic studies suggest that it’s not even a proper tyrannosaurid (the family that contains all the Campanian-Maastrichtian Laramidian genera), and it might represent a wholly different branch of the greater tyrannosaur family tree, unique to Appalachia, which (mind you) was separated from Laramidia for tens of millions of years ago (Deinosuchus venturing into saltwater would explain why it shows up on both sides), as the Western Interior Seaway had split the continent in half around 100 million years ago and didn’t subside until the Maastrichtian, meaning transcontinental migrations for land-bound non-avian dinosaurs in North America was basically impossible for a very long time.

Description

This is taken from the 2000 book Walking with Dinosaurs the Evidence, written by Darren Naish and David Martill, a tie-in to 1999’s Walking with Dinosaurs, which explains some of the thought processes behind the (now very dated) portrayals of the animals included in that series. I’ve posted this for the sake of offering some easily accessible information regarding some of the most controversial creative choices taken in the series.

So the “one-ton crocodile” from “Death of a Dynasty” has caused quite a bit of confusion among fans and unsurprisingly so, given the frankly shoddy way it was handled. If you need a memory jog, the episode features an animatronic crocodile head floating about and eyeing the duckbills and “Quetzalcoatlus” menacingly but since they didn’t have the budget to animate a crocodile attack, that’s as much screentime as it gets. But what is that crocodile supposed to be? The crocodiles known from Hell Creek tend to be on the dinky side, like Borealosuchus and Brachychampsa, with the largest one, the basal gavialoid Thoracosaurus reaching about 15 feet (possibly 20-25 feet based on some material) but it was no killer of dinosaurs. Fun fact, both Borealosuchus, and Thoracosaurus made it past the K-Pg extinction, the former even surviving into the Early Eocene, where it reached 15 feet long (B. wilsoni).

So is the crocodile meant to be Thoracosaurus? It does have a somewhat narrow rostrum but it’s not exactly comparable to that of a gharial, and according to the 2000 book, this is actually meant to be the gigantic, infamous killer of dinosaurs; Deinosuchus, the “terrible crocodile” of Laramida, or more accurately alligator, as it’s a basal member of the alligatoroid lineage, which includes today’s Alligator and caimans. What now? Yeah, I was just as confused as you were about this claim but after looking into it some more, I can speculate about the reasons behind the discrepancies. In a nutshell, I think both Crawly Creatures, as well as whoever was writing Kenneth Branagh’s narration screwed up big time. In the latter case, a weight of one ton is something the biggest extant members of Crocodylus can attain, specifically the saltwater and Nile crocodile, if they reach their max length of 20 feet, and obviously, a giant like Deinosuchus would have weighed a lot more, especially if you consider that the longer a croc gets its body mass increases exponentially. At 40 feet, Deinosuchus would have weighed as much as a T. rex (circa 8 tons).

And yes, it’s also odd that Deinosuchus never gets namedropped, especially since Branagh handled more complex names such as Eustreptospondylus. In other such cases in the WW series, this was done to handwave anachronisms/geographical displacements (albeit not consistently, like with Anurognathus), or so they could use cooler terms (like brontothere and gorgonopsid, instead of Embolotherium and Inostrancevia), and while you could argue that this was a case of the former, I have my doubts (more on it later). As for the animatronic head, it seems to have been based on the reconstructed skull for Deinosuchus hatcheri, which has a more bulbous snout tip compared to Deinosuchus riograndensis, but they made the rostrum far too narrow and ended up with a head that looks more like that of Sarcosuchus, while the real-life Deinosuchus had a very broad and robust skull and jaws that allowed it to crush turtles and drag dinosaurs to a watery grave. The novelization for WWD also refers to it as Deinosuchus and gives it an expanded role, while also touting the (very dated) 50-foot max estimates. By contrast, the 2000 book (as you can see) gives it a rather conservative and more reasonable max size of 33 feet (it also gives Quetzalcoatlus a more conservative wingspan of 38 feet), which was pleasantly surprising XD Okay, so we can confidently say that the “Death of a Dynasty” croc was indeed meant to be Deinosuchus but done dirty, but what about anachronism?

As you can see, the book addresses that, saying how the giant croc is only known from older rocks in Montana, which more specifically, is alluding to the Judith River Formation, which preserved some fairly large postcranial remains of Deinosuchus, stemming from individuals in the 35-40 foot range. While we haven’t found anything close to a complete skeleton, remains of Deinosuchus, usually in the form of skulls and jaws (often incomplete), isolated teeth, and isolated postcranial fossils, have been found all across North America, with many hailing from the eastern United States, but we have also found plenty of specimens in the west, mainly in the Texan Aguja Formation, which contains some of the largest specimens to date, comparable to the Judith River remains. The oldest occurrence of Deinosuchus is at the lower Blufftown Formation, dating to the early Campanian (83-80 my), while the youngest fossils date to the late Campanian (74-73 mya), such as fossils from the upper layers of the Black Creek, Demopolis Chalk and (once more) Blufftown Formations, while the Laramidian specimens tend to cluster in the 79-75 mya range, showing us that the genus (or at least a bunch of related large-sized estuarine basal alligatoroids) lasted for some 10 million years. This reflects how ectothermic, more generalized crocodylomorphs have a better chance at longevity than endothermic, more specialized and active dinosaurs and pterosaurs, but Deinosuchus itself eventually faced a massive hurdle. Given that these animals are usually found in estuaries and brackish water environments, it can be presumed that the disappearance of the great inland sea, which happened right before T. rex and its contemporaries arrived on the scene, was the reason behind the great croc’s extinction.

Given WWD’s lax attitude towards anachronism, and the fact that back in 1999, wastebasket taxonomy led to many Late Cretaceous archosaurs in North America having fossil ranges spanning from the Campanian to the late Maastrichtian, like Campanian azhdarchid fossils from Two Medicine and Dinosaur Park (the latter now identified as Cryodrakon) being attributed to Quetzalcoatlus, or in the case of fragmentary fossils of deinonychosaurians from Hell Creek (largely isolated teeth) being attributed to the Campanian Saurornitholestes, Dromaeosaurus, and Troodon (now Acheroraptor and Pectinodon), and others like Edmontonia (the Hell Creek species is now referred to as Denversaurus) and Chirostenotes also being treated as overly inclusive wastebasket taxa (with the fossils of Anzu, first discovered in 1998, initially attributed to Chirostenotes), you can see how the WWD crew could have felt justified in putting Deinosuchus as a contemporary of T. rex, since the more sharply defined line between Campanian and Maastrichtian archosaurs in Laramidia today was much blurrier and more ill-defined back in 1999. For context, most genera that did cross the boundary tend to cluster around the late Campanian-early Maastrichtian, while others, like Edmontosaurus, only showed up at the tail-end of the Campanian, 73 mya.

Though there is an interesting tidbit that might have served as additional inspiration (though this is speculative on my part), as some large but fragmentary crocodile fossils (large teeth and vertebrae) from Maastrichtian rocks in New Jersey and Delaware were tentatively attributed to Deinosuchus by some, leading to speculation about the genus having survived into the Maastrichtian. However, modern workers, including David Schwimmer (a foremost authority of Deinosuchus) are skeptical of that, suggesting that they may instead belong to Thoracosaurus (contributing to those controversial upper estimates mentioned earlier) or some other, indeterminate crocodilian. Giant crocodylomorphs pop up rather sporadically in the fossil record of the Mesozoic, and perhaps it’s not impossible that some other giant crocodilian (perhaps even a descendent of Deinosuchus itself that managed to adapt to the Maastrichtian’s challenge) inhabited Maastrichtian North America, but the absence of even a single tooth from Hell Creek (when we have such an extensive record of smaller crocs and various other riparian animals from this flood plain environment) suggests that they weren’t present in the general Hell Creek region specifically.

And as an aside, the entry also brings up how the giant alligator might have preyed on tyrannosaurs, citing a specimen of Albertosaurus that bears tooth marks attributed to a Deinosuchus. This is referencing a tyrannosaur specimen from Demopolis Chalk discovered in 1982, which was tentatively attributed to Albertosaurus by some workers, since it shared some anatomical features of albertosaurines (Albertosaurus and Gorgosaurus), but also since Albertosaurus was something of a wastebasket taxon for Late Cretaceous tyrannosaurs in the past (being the first one to be named, along with Tyrannosaurus, back in 1905). But in 2005, it was properly described as a distinct taxon, Appalachiosaurus montgomeriensis (an immature specimen at that), and later phylogenetic studies suggest that it’s not even a proper tyrannosaurid (the family that contains all the Campanian-Maastrichtian Laramidian genera), and it might represent a wholly different branch of the greater tyrannosaur family tree, unique to Appalachia, which (mind you) was separated from Laramidia for tens of millions of years ago (Deinosuchus venturing into saltwater would explain why it shows up on both sides), as the Western Interior Seaway had split the continent in half around 100 million years ago and didn’t subside until the Maastrichtian, meaning transcontinental migrations for land-bound non-avian dinosaurs in North America was basically impossible for a very long time.