Dermodactlyus: America's first Jurassic Pterosaur

Skye McDavid, February 15, 2024

Most of the earliest pterosaur discoveries were in Europe, and focused on the Jurassic Solnhofen Plattenkalk in southern Germany. The first Pterosaur reported from outside of Europe was presented to the Academy of Natural Sciences of Philadelphia by Edward Cope in 1866, from the Triassic of Pennsylvania. (Cope in Anon, 1866) However, this is probably not a pterosaur and very likely a Kuehneosaurid, a gliding reptile convergent with modern Draco lizards. (Witton 2010) 

The next American pterosaur discovery was possibly by Othniel Marsh himself. Marsh had a habit of taking credit for other's work, but often noted who had found fossils he published. In this case, he claims to have found the fossil himself. (Marsh 1871) Whether it was Marsh himself or one of his field crew who found it might be somewhere in Marsh's archives, but that's a deep dive I don't have the time for. All I can confirm for now is that Marsh claimed credit and history is written by those who write stuff down. This find, along with several other finds from the early 1870s were from the Late Cretaceous of Kansas, and would eventually be assigned to the genera Nyctosaurus and Pteranodon. (Witton 2010)

As Marsh pointed out, the toothless Late Cretaceous pterosaurs of Kansas were quite different from the often toothy pterosaurs of Jurassic Europe. (Marsh 1881) 

The first Jurassic Pterosaur to be found in the Americas was found by Samuel Wendell Williston in what Marsh calls the 'Atlantosaurus beds,' now termed the Morrison Formation, at Como Bluff, Wyoming. Among the many giant sauropod bones, a single partial metacarpal only a 3 centimeters long was proof that flying reptiles were present in the same ancient ecosystem. This bone was shipped to Marsh at Yale and was reported in August of 1878. (Marsh 1878) 

Marsh first named the specimen Pterodactylus montanus, and later Dermodactylus montanus. (Marsh 1878, 1881) The name 'skin finger' refers to the membranous patagium supported by the wing finger, while montanus refers to the Rocky Mountains. 

As with many Marsh taxa, Dermodactylus is now treated as a nomen dubium. Colbert interpreted it as a Rhamphorhynchid and compared it to Nesodactylus from Cuba, while Wellnhofer assigned it to Pterodactyloidea incertae sedis. Better pterosaur fossils from the Morrison Formation and other Jurassic rocks have been found since, but Dermodactylus' story is one worth remembering.


Anonymous (1866) October 23d. Proceedings of the Academy of Natural Sciences of Philadelphia 18, 290-291 [view on JSTOR]

Colbert EH (1969) A Jurassic Pterosaur from Cuba. American Museum Novitates 2370, 1-26 [view on BHL]

Marsh OC (1871) Note on a new and gigantic Species of Pterodactyle. American Journal of Science S3-1(6), 472 [view on BHL]

Marsh OC (1878) New Pterodactyl from the Jurassic of the Rocky Mountains. American Journal of Science S3-16(93), 233-234 doi: 10.2475/ajs.s3-16.93.233

Marsh OC (1881) Note on American Pterodactyls. American Journal of Science S3-21(124), 342-343 doi: 10.2475/ajs.s3-21.124.342

Wellnhofer P (1978) Handbuch der Paläoherpetologie, Teil 19: Pterosauria. Gustav Fischer Verlag. [In German; Encyclopedia of Paleoherpetology, Part 19: Pterosauria]

Witton MP (2010) Pteranodon and beyond: the history of giant pterosaurs from 1870 onwards. Geological Society London Special Publications 343, 313-323 doi: 10.1144/SP343.19