I've finally finished it! Dimorphodon macronyx is a dimorphodontid pterosaur from the Early Jurassic of England. Its remains were first found by Mary Anning in 1828 on the coast of Dorset. At first, the animal was classified as a Pterodactylus species, but sir Richard Owen, who described two more specimens, identified a new genus in 1859. Dimorphodon reached a meter in length and had a wingspan of 1.45 m. Its most recognizable feature is a 23 cm long skull with large holes to reduce weight. There were large "fangs" and numerous small teeth in the jaws. Dimorphodon is believed to have fed on small vertebrates and possibly insects. Judging by its relatively short wings and heavy skeleton, it was not a good flyer. This is a secondary feature: earlier, Triassic pterosaurs were good fliers.
Hailing from Late Triassic North America, Caelestiventus hanseni turned what we knew about pterosaurs on its head. Before its description in 2015, it was thought that all of the early pterosaurs of the Late Triassic were small coastal animals, feeding on fish and insects by the shore. But Caelestiventus lived in a desert, 65 million years before other known desert-dwelling pterosaurs. Also, up until its discovery, only some pterodactyloid pterosaurs were known to he desert-dwellers, but Caelestiventus was a dimorphodontid. Dimorphodon itself being found in the Early Jurassic, this puts the origins of the dimorphodontid family much further back than originally thought, and in North America. Caelestiventus is also the oldest known pterosaur from North America.
While most Triassic pterosaurs are very small, Caelestiventus was (comparatively) large with a 17.8 cm (7.0 in) long skull and estimated 1.5 meters (4.9 ft) long wingspan. The only known specimen is a subadult, so it’s possible Caelestiventus could have grown larger. It had three different tooth shapes: long fang-like spikes, large "leaf-shaped" blades, and tiny blades, which it may have used to catch and eat lizards and small insects.
Found in the Nugget Sandstone Formation, Caelestiventus would have of course lived in a large desert full of sandy dunes, dotted by seed plants of the extinct, cycad-like order Bennettitales. No other named fossils are known from this area, though theropod tracks have been found, and indeterminate fragments of theropods, sphenosuchians, drepanosaurids, sphenodontians, and lepidosaurs are known.
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Caelestiventus — рід птерозаврів, що існував у пізньому тріасі (208 млн років тому). Caelestiventus є єдиним прикладом нептеродактилоїдного птерозавра, що мешкав в пустелі, і він на 65 мільйонів років старший за інших відомих птерозаврів, що мешкали у пустелі. Крім того, це показує, що навіть найдавніші птерозаври були морфологічно та екологічно різноманітними і що Dimorphodontidae виникли…
Time and Place: 208 million years ago, in the Norian of the Late Triassic
Caelestiventus is only known from Utah.
Physical Description: Caelestiventus is known from only one specimen, which preserves one of the wing fingers and much of the skull. But the skull is very interesting. It’s deep and narrow, similar to its relative Dimorphodon. The top margin of the skull is mostly convex, but the forehead has a slight dip. As reconstructed in the description, the skull almost looks like that of a skeksis, but that reconstruction probably exaggerates the dip too much. There are two morphs of teeth, with longer, fanglike teeth in front of both jaws. The upper jaw has shorter, wider teeth in the back at the jaw, with two cusps each, and the lower jaw has many tiny triangular teeth in the back. The inner sides of the lower jaws show a groove, which probably supported a pouch. Based on the skull, the wingspan of Caelestiventus is estimated at being a little over 1.5 meters, but the only known specimen appears to be immature, because the skull bones are unfused.
Diet: Caelestiventus was probably a carnivore. Its teeth would have been well-suited for grabbing small prey such as sphenodontians, small pseudosuchians, and other lizardy things.
Behavior: Not much is known about Caelestiventus’s behavior, because not much is known of Caelestiventus. Dimorphodontids were not great at flying; their wings were not particularly large compared to the body, and like modern fowl, flight would have been strenuous but not impossible. Caelestiventus t likely foraged on the ground, and only took to the wing when it needed to, e.g. to escape from predators. The pouch on the throat may have been used to store prey, or for visual or auditory communication.
Ecosystem: Caelestiventus was found in the Nugget Sandstone of Utah - specifically at the Saints and Sinners Quarry, and yes that’s a cool name. The Saints and Sinners environment was a dry, sandy desert, much like the region is today. This makes Caelestiventus the oldest-known desert-dwelling pterosaur. The quarry area is concentrated around what used to be an oasis in the desert; the Saints and Sinners community probably concentrated around the last oasis in a drought-stricken region, and were buried by a massive sandstorm. Other creatures that lived in this desert included bizarre digging drepanosaurs, sphenodonts, two sphenosuchians, and two species of theropod (one coelophysoid and one larger taxon). Over 11,500 bones have been excavated so far, the majority of which belong to the theropods.
Other: I got to hold a 3D-printed cast of Caelestiventus’s skull before it was published!
~ By Henry Thomas
Sources under the cut
Britt, B.B., Chure, D.J., Engelmann, G.F., Shunway, J.D. 2016. Rise of the Erg - Paleontology and Paleoenvironments of the Triassic-Jurassic Transition in Northeastern Utah. Geology of the Intermountain West 3: 1-32.
Britt, B.B., Dalla Vecchia, F.M., Chure, D.J., Engelmann, G.F., Whiting, M.F., Scheetz, R.D. 2018. Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years. Nature Ecology & Evolution 2: 1386-1392
Witton, M.P. 2015. Why Dimorphodon macronyx is one of the coolest pterosaurs. http://markwitton-com.blogspot.com/2015/06/why-dimorphodon-macronyx-is-one-of.html
